HK1187071B - Fuel and process for powering a compression ignition engine - Google Patents

Description

Fuel and method for powering a compression ignition engine

The present invention relates to a fuel and a method for powering a compression ignition internal combustion engine.

The present application claims priority from australian patent applications AU2010905226 and AU 2010905225. The present application also relates to an international application entitled "process for making an expression and identification of an entity and a method for making. The description of the related international application is incorporated herein by reference.

Background

The quest for fuel alternatives to conventional fossil fuels is driven primarily by the need for "clean" emissions fuels, coupled with low production costs and wide availability. Much attention has been given to the environmental impact of fuel emissions. Research on alternative fuels is focused on fuels that will reduce the amount of particulate matter and oxides produced by the combustion of the fuel, as well as on reducing non-combusted fuels and CO₂Is discharged andother combustion products.

The push for environmentally friendly fuel compositions for delivery applications has focused on ethanol. Biological materials such as plant organics can be converted to ethanol, and the ethanol produced by this process has been used as a partial replacement for fuels for spark-ignition engines. While it reduces the dependence on non-renewable resources in terms of fuel, in a general sense, the environmental results produced by using these fuels in engines are not significantly improved, with cleaner combustion being offset by the continued use of such fuels in less efficient spark-ignition engines, and the negative environmental effects associated with the use of energy, arable land, fertilizers, and irrigation water to produce fuel.

Other fuel alternatives for complete or partial replacement of traditional fuels have not been widely used.

One major drawback of the complete replacement of traditional fuels, and in particular fuels for compression ignition engines (diesel fuels), by renewable alternative fuels relates to the perceived problems associated with the low cetane index of these fuels. Such fuels present the problem of achieving ignition in the manner required for efficient engine operation.

The applicant has also recognised that in some remote areas or environments water is a scarce resource and in such areas it may be desirable to generate electricity (for example by diesel engine) plus capture of the water by-product for re-use in the local community. In addition, moving large amounts of energy through liquid pipelines is a long-standing and cost-effective technique in terms of moving large amounts of energy over long distances with minimal visible impact, as compared to overhead transmission lines.

The applicant has also recognised that in some regions there is a need to capture the heat generated in such industrial processes and re-use it in the local community. In some examples, this need is combined with the need to capture water for reuse mentioned above.

In short, there is a continuing need for alternative fuels for internal combustion engines. Of interest are fuels that can reduce emissions, particularly where improved emission characteristics are obtained without a significant adverse impact on fuel efficiency and/or engine performance. There is also a need for a method for powering a compression ignition engine such that such engine operates on a diesel alternative fuel that contains components that have not traditionally been considered suitable for such applications. There is also a need for diesel engine fuels and engine operating methods suitable for use in remote locations or environmentally sensitive environments (e.g., high altitude marine environments, particularly harbour areas in terms of emissions) or other areas (e.g., remote dry and cold inland areas) that can maximize the use of all byproducts of engine operation, including, for example, thermal and water byproducts. Preferably, these objectives are achieved with as little loss (penalty) of fuel efficiency and engine performance as possible.

Disclosure of Invention

According to the present invention there is provided a method of powering a compression ignition engine using a main fuel comprising methanol and water, and comprising:

fumigating an incoming air stream with a fumigant comprising an ignition enhancer;

introducing the fumigated intake air into a combustion chamber of an engine and compressing the intake air;

introducing a primary fuel into the combustion chamber; and

the main fuel/air mixture is ignited to drive the engine.

According to the present invention there is also provided a diesel engine fuel for a compression ignition engine, the fuel being fumigated into the air intake of the engine with a fumigant comprising an ignition enhancer, the fuel comprising methanol, water and one or more additives selected from: ignition improvers, fuel extenders, combustion enhancers, oxygen absorbing oils, lubricity additives, product coloring additives, flame color additives, anti-corrosion additives, biocides, pour point depressants (freezepointdepressants), deposit reducers (deposityreducants), denaturants, pH control agents, and mixtures thereof.

According to the methods described herein, the present invention can result in simplification and lower cost of fuel production and reduced environmental impact by eliminating the need to produce high purity components and by-product components, by accepting blends of such components into the fuel. Cost and environmental benefits may also accrue from using the fuel in cold climates, as the freezing point of the fuel may readily meet any low temperature environment that may be encountered.

The exhaust gas produced by the combustion of the fuel may contain low-grade impurities, making it ideal for subsequent processes. As one example, CO may be converted to CO using an energy source (which may include renewable energy sources, including solar energy)₂Conversion back to methanol for direct reduction of greenhouse gas CO₂Or alternatively, high purity CO may be mixed₂For organic growth (e.g., algae) for many end uses, including methanol production.

In some embodiments, water produced during the combustion of the fuel may be recovered, which is an important advantage for remote areas where water is scarce. In other examples, heat generated during diesel engine operation may be used for local heating needs. Thus, some embodiments provide a power generation system that utilizes the water and/or heat output of the engine in a suitable manner by operation of the diesel engine.

According to one aspect, there is provided a method for supplying fuel to a compression ignition engine, the method comprising:

-supplying a main fuel composition comprising methanol and water to a first vessel in fluid connection with a combustion chamber of a compression ignition engine, and

-supplying a secondary fuel component comprising an ignition enhancer to a second vessel fluidly connected to an air intake of the compression ignition engine.

According to another aspect, there is provided a power generation system comprising:

generating power using the methanol-water fuel to power the compression ignition engine;

preheating an incoming air stream of a compression ignition engine and/or fumigating the incoming air stream with an ignition enhancer;

treating engine exhaust gas to recover heat and/or water exhausted from the engine, an

The heat and/or water is redirected for further use.

According to another aspect, a method of delivering a two part pre-fuel composition comprising methanol and ether is provided, comprising delivering a pre-fuel from a first location to a second location remote from the first location, and separating the ether from the methanol to produce a first fuel part comprising methanol and a second fuel part comprising the ether.

According to yet another aspect, there is also provided a pre-fuel composition comprising methanol and up to 10% by weight of ether.

Drawings

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a flow diagram illustrating a process for powering a compression ignition generator according to one embodiment of the present invention;

figure 2 is a graph plotting the weight% (compared to the weight of the main fuel) of dimethyl ether (DME) as an ignition enhancer to be fumigated into an engine versus the temperature change of the compressed main fuel/fumigant/air mixture for three main fuel compositions (100% methanol, 70% methanol: 30% water and 40% methanol: 60% water). The figure relates to the situation when no other ignition enhancement technique is present.

FIG. 3A is a flow chart illustrating a method for powering a compression ignition engine and treating engine exhaust gas, wherein waste heat is used as a separate heat source via a hot water circuit;

FIG. 3B is a flow chart similar to FIG. 3A, but which does not include the step of fumigating the engine intake.

FIG. 4A is a more detailed illustration of the exhaust treatment of the flow chart of FIGS. 3A and 3B.

Fig. 4B is a similar illustration to fig. 4A, but without the final exhaust air exchange condenser.

Fig. 5A is a flow chart illustrating a method for powering a compression ignition engine to drive a rail vehicle and treat engine exhaust.

FIG. 5B is a flow chart similar to FIG. 5A, but which does not include the step of fumigating the engine intake.

FIG. 6A is a flow chart illustrating a method for powering a compression ignition engine to drive a marine vehicle and treat engine exhaust.

FIG. 6B is a flow chart similar to FIG. 6A, but which does not include the step of fumigating the engine intake.

Fig. 7 is a graph illustrating the braking thermal efficiency of a compression ignition engine fumigated with DME using a main fuel containing varying amounts of water and varying amounts of methanol, DME and DEE in liquid phase.

FIG. 8 is a graph illustrating the braking thermal efficiency of a compression ignition engine using a main fuel containing varying amounts of ether as an ignition enhancer and using DME as a fumigant.

Fig. 9 is a graph illustrating the NO exhaust gas output of a compression ignition engine using a main fuel containing varying amounts of water and using DME as a fumigant.

FIG. 10 is a schematic of the method and test equipment instrumentation used to obtain the results of example 1.

FIG. 11 is a graph illustrating the reduction of NO exhaust output of a compression ignition engine by increasing the amount of water in a methanol-water fuel.

Detailed Description

The fuels and methods described herein are suitable for powering Compression Ignition (CI) engines. In particular, the fuel and method are most suitable for, but not limited to, CI engines operating at low speeds, such as 1000rpm or less. The rotational speed of the engine may even be 800rpm or less, for example 500rpm or less. The speed of the engine may even be 300rpm or less, for example 150rpm or less. Thus, the fuel is suitable for larger diesel engines, such as those operating on ships and trains, and in power plants. The lower speed of larger CI engines allows sufficient time for the selected fuel composition to burn completely and for a sufficiently high percentage of the fuel to evaporate for efficient operation.

However, it should be understood that the fuels and methods described herein can be operated using smaller CI engines operating at higher speeds. In fact, preliminary test work was conducted on small CI engines operating at 2000rpm and 1000rpm, indicating that the fuel is also capable of powering such higher speed engines. In some examples, the adjustments may assist in using the fuel and method on smaller (higher rpm) CI engines, some of which are detailed below.

Fuel composition

The fuel composition forming the primary fuel for the process comprises methanol and water. The fuel is a compression ignition engine fuel, i.e., a diesel engine fuel.

To date, methanol has not found commercial application in compression ignition engines. The low cetane index of methanol, which is 3 to 5, highlights the disadvantage of using methanol as motor fuel (pure or blended). This low cetane index makes methanol difficult to ignite in CI engines. Blending water with methanol further reduces the cetane index of the fuel making combustion of the methanol/water blend fuel even more difficult, and thus, it is considered counterintuitive to use water in combination with methanol in CI engines. One of the roles of water after fuel injection is cooling, as water heats up and evaporates, which further reduces the effective cetane. However, it has been found that methanol-water fuel compositions can be used in compression ignition engines in an efficient manner and with cleaner exhaust emissions, provided that the engine is fumigated with a fumigant comprising an ignition enhancer. Other factors, detailed below, also help to maximize efficient operation of CI engines with this fuel.

Methanol has been previously described for use in fuel compositions, but as a heating or cooking fuel, wherein the fuel is combusted to produce heat. The principles applicable to diesel engine fuels are very different because the fuel must be ignited under compression conditions in a compression ignition engine. Little, if any, methanol may be collected when using methanol and other components in the cooking/heating fuel.

The main fuel may be a homogeneous fuel or a single phase fuel. The fuel is typically not an emulsified fuel comprising separate organic and aqueous phases emulsified together. Thus, the fuel may be free of emulsifiers. The tuning of the additive components in the fuel is aided by the dual solubility characteristics of both methanol and water, which will allow a wider range of materials to be dissolved at a variety of water to methanol ratios and concentrations available.

All amounts mentioned herein refer to weight unless otherwise indicated. When describing the percentage amounts of a component in a main fuel composition, it refers to the percentage by weight of that component to the total main fuel composition.

In a broad sense, the relative amount of water to methanol in the main fuel composition may be from 0.2: 99.8 to 80: 20 by weight. According to some embodiments, the minimum water content level (relative to methanol) is 1: 99, e.g. the lowest ratios are 2: 98, 3: 97, 5: 95, 7: 93, 10: 90, 15: 95, 19: 81, 21: 79. According to some embodiments, the upper limit (relative to methanol) of water in the combination is 80: 20, such as 75: 25, 70: 30, 60: 40, 50: 50, or 40: 60. The relative amount of water in the composition can be considered to be within a "low to medium water content" level range, or a "medium to high water content" level range. The "low to medium water content" level ranges from any of the lowest levels shown above to the highest level of 18: 82, 20: 80, 25: 75, 30: 70, 40: 60, 50: 50 or 60: 40. The "medium to high water content" level ranges cover the range from 20: 80, 21: 79, 25: 75, 30: 70, 40: 60, 50: 50, 56: 44 or 60: 40 to the highest level of one of the upper limits indicated above. Typical low/medium water content levels range from 2: 98 to 50: 50, and typical medium/high water content levels range from 50: 50 to 80: 20. Typical low water levels range from 5: 95 to 35: 65. Typical intermediate water content levels range from 35: 65 to 55: 45. Typical high water levels range from 55: 45 to 80: 20.

The relative amount of water in the main fuel composition may be a minimum of 0.2%, or 0.5%, or 1%, or 3%, or 5%, 10%, 12%, 15%, 20%, or 22% by weight, in view of the percentage by weight of water in the total main fuel composition. The maximum amount of water in the total main fuel composition may be 68%, 60%, 55%, 50%, 40%, 35%, 32%, 30%, 25%, 23%, 20%, 15% or 10% by weight. Any minimum level may be combined with the maximum level without limitation, except that the minimum level is required to be below the maximum water content level.

Based on the test results reported in the examples, the amount of water in the fuel composition is, in some embodiments, from 0.2% to 32% by weight in terms of desired Braking Thermal Efficiency (BTE). The optimum region for the peak in braking thermal efficiency of methanol-water pressure combustion engine fuels is 12% to 23% by weight water in the main fuel composition. The range may be incrementally narrowed from the wider to the narrower of the two ranges. In some embodiments, it is combined with the amount of ignition enhancer in the main fuel composition (no greater than 15% by weight of the main fuel composition). Details of the ignition enhancer are given below.

Based on the other test results reported in the examples, the amount of water in the fuel composition is, in some embodiments, from 22% to 68% by weight, in terms of the maximum reduction in NOx emissions. The optimal zone for maximum reduction of NOx emissions is 30% to 60% by weight of the main fuel composition of water. The range may be incrementally narrowed from the wider to the narrower of the two ranges. Because NO is the primary NOx emission component, NO emissions can be referenced as a greater proportion or indication of the extent of total NOx emissions.

In some embodiments, the main fuel composition comprises from 5% to 40% water, for example from 5% to 25% water, from 5% to 22% water, by weight of the main fuel composition, with respect to the desired balance of fuel properties and emissions. These levels are based on a combination of test results reported in the examples.

For operation of a compression ignition engine using a methanol/water main fuel composition and fumigation without other ignition enhancement techniques (e.g. inlet preheating or air blowing), the water content in the fuel may be low to moderate, preferably low. Where the water content level is at the higher end, the method generally benefits from intake air and/or primary fuel preheating, thereby overcoming the increased cooling effect of the increased water content level in the primary fuel composition. Preheating may be achieved by a variety of techniques, discussed in more detail further below.

The amount of methanol in the total main fuel composition is preferably at least 20% by weight of the main fuel composition. According to some embodiments, the amount of methanol in the fuel composition is at least 30%, at least 40%, at least 50%, at least 60%, or at least 70% of the fuel composition. The amount of water in the total main fuel composition may be at least 0.2%, at least 0.5%, at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, at least 15%, at least 16%, at least 17%, at least 18%, at least 19%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, and at least 70%. As the weight of water in the main fuel composition increases, it is increasingly surprising that fumigating the charge with fumigant overcomes the loss of water in the fuel on ignition, operates smoothly on COV of IMEP, and produces a net power output.

The combined amount of methanol and water in the total main fuel composition may be at least 75%, such as at least 80%, at least 85% or at least 90% by weight of the fuel composition. The main fuel composition may comprise one or more additives in a combined amount of at most 25%, or at most 20%, or at most 15%, or at most 10% by weight of the main fuel composition. In some embodiments, the total level or combined level of additives is no greater than 5% of the main fuel composition.

The methanol used to produce the main fuel composition may be from any source. As an example, the methanol may be produced methanol or waste methanol, or crude methanol or semi-refined methanol or unrefined methanol. Crude or spent or semi-refined methanol may typically comprise primarily methanol, with the balance being water and equivalent amounts of higher alcohols, aldehydes, ketones or other carbon, hydrogen and oxygen molecules produced during normal methanol production. Waste methanol may or may not be suitable depending on the degree and type of contamination. In the above section reference to the ratio of methanol to water or the amount of methanol by weight in the fuel composition refers to the amount of methanol itself in the methanol source. Thus, where the methanol source is crude methanol comprising 90% methanol and other components, the amount of crude methanol in the fuel composition is 50%, and the actual amount of methanol is considered to be 45% methanol. Unless otherwise indicated, the water component of the methanol source is considered when determining the amount of water in the fuel composition, and other impurities are considered additives when evaluating the relative amounts of the components in the product. Higher alcohols, aldehydes and ketones, which may be present in the crude methanol, may serve as soluble fuel extender additives.

According to some embodiments, the primary fuel comprises crude methanol. The term "crude methanol" encompasses low purity methanol sources, such as methanol sources comprising methanol, water, and may be up to 35% non-aqueous impurities. The methanol content of the crude methanol may be 95% or less. The crude methanol can be used directly in the fuel without further purification. Typical non-aqueous impurities include higher alcohols, aldehydes, ketones. The term "crude methanol" includes spent methanol, crude methanol and semi-refined methanol. A particular advantage of this embodiment is that crude methanol containing higher levels of impurities can be used directly in the fuel for CI engines without expensive purification. In such a case, the additive (i.e., crude methanol impurities other than water and other fuel composition additives) level may be up to 60% of the main fuel composition (including impurities in the crude methanol). For main fuel compositions that use higher purity methanol (e.g., 98% or greater purity methanol) as a source, the total additive level can be lower, e.g., no greater than 25%, no greater than 20%, no greater than 15%, or no greater than 10%.

Any suitable mass of water may be used as a source of water for producing the main fuel composition. The source of water may be water comprising a portion of undistilled crude methanol, or recycled water, or crude or contaminated water (e.g., brackish seawater) purified by reverse osmosis, purified by active substances such as activated carbon or other chemical treatment, deionization, distillation or evaporation techniques. The water may be from a combination of these sources. As one example, the source of water may be water recovered from water-rich exhaust of a combustion ignition engine. The water may be recovered by a heat exchanger and spray chamber or other similar operation. Such recovery and reuse techniques allow clean exhaust emissions. In this case, the water is recovered back into the engine with or without any captured unburned fuel, hydrocarbons or particulate matter or other combustion products back into the engine and recovered through a loop combustion step until disposal or otherwise treated by known purification means. In some embodiments, the water may be a brine, such as seawater, which has been purified to remove salts therefrom. This embodiment is suitable for marine applications, such as in marine CI engines, or for operation of CI engines in remote islands.

The quality of the water will corrode and create the deposit characteristics of the engine from the supply chain up to the point of injection into the engine, and in these cases it may be necessary to properly treat the main fuel with anti-corrosion additives or other methods.

The amount of additive included in the base fuel may take into account any downstream dilution caused by the addition of water (for example) to the fuel.

Additives that may be present in the main fuel composition may be selected from one or more of the following categories, but not exclusively:

1. an ignition improver additive. They may also be referred to as ignition enhancers. The ignition improver is a component that promotes the occurrence of combustion. Molecules of this type are inherently unstable, and this instability leads to a "self-starting" reaction that causes combustion of the main fuel component (e.g., methanol). The ignition improver may be selected from materials known in the art to have ignition enhancing properties, such as ethers (including C1-C6 ethers, such as dimethyl ether), alkyl nitro esters, alkyl peroxides, volatile hydrocarbons, oxygenated hydrocarbons, and mixtures thereof.

In addition to typical ignition enhancers, the finely divided carbohydrate particles present in the combustion zone may or may not have the effect of acting as an ignition enhancer after the liquid fuel component evaporates prior to ignition, however, the presence of such species may contribute to more complete and rapid combustion of the overall air/fuel mixture.

While other ignition promoters may be added to the primary fuel, the techniques described herein facilitate ignition through an engine operating range without such addition. Thus, according to some embodiments, the primary fuel is free of an ignition improver additive. In other embodiments, the primary fuel is DME free (although it may contain other ignition promoters). In the case of dimethyl ether as an ignition improver, according to some embodiments less than 20%, less than 15%, less than 10%, less than 5%, less than 3%, less than 1% dimethyl ether is present in the fuel composition or no dimethyl ether is present. In some embodiments, the amount of ether (of any type, such as dimethyl ether or diethyl ether) in the main fuel composition is less than 20%, less than 15%, less than 10%, less than 5%.

In some embodiments, at least 80% of the ignition enhancer present in the main fuel composition is provided by one or at most two specific chemicals, examples being dimethyl ether and diethyl ether. In one embodiment, a single chemical identity (identity) ignition enhancer is present in the main fuel composition. In one embodiment, at least 80% of the ignition enhancer in the main fuel composition is comprised of an ignition enhancer of a single chemical nature. In each case, the single ignition enhancer or > 80% of the ignition enhancer component making up the ignition enhancer may be dimethyl ether. In other embodiments, the ignition enhancer comprises a mixture of three or more ignition enhancers.

In some embodiments, the amount of ignition enhancer in the main fuel composition is no greater than 20%, such as no greater than 10% or no greater than 5% of the fuel composition.

2. A fuel extender. Fuel extenders are materials that provide thermal energy to drive an engine. To the extent that it is included in a fuel composition, the material used as a fuel extender may serve this purpose as the primary purpose, or the additive material may provide this and another function.

Examples of such fuel extenders are:

a) a carbohydrate. Carbohydrates include sugars and starches. Carbohydrates may be included for fuel extender purposes, but may also be used as ignition and/or combustion promoters. Preferably, the carbohydrate is water/methanol soluble, has a higher water content level, has greater sugar solubility, for example in the main fuel. The water-rich (single phase) main fuel composition dissociates carbohydrates (e.g., sugars), but as the liquid solvent (water/methanol) in the fuel composition evaporates in the engine, the carbohydrate solutes can form fine, high surface area suspended particles of the low LEL (lower explosive limit) composition that will decompose/react under engine conditions, increasing the flammability of the main fuel mixture. To achieve an increase in the flammability of the mixture, it is preferred that the amount of carbohydrate additive is at least 1%, preferably at least 1.5% and more preferably at least 5%.

b) A soluble fuel extender additive. The fuel extender additive is a combustible material. These additives may be added as separate components or may be added as part of the undistilled methanol used to produce the main fuel composition. Such additives include C2-C8 alcohols, ethers, ketones, aldehydes, fatty acid esters, and mixtures thereof. Fatty acid esters such as fatty acid methyl esters may have a biofuel origin. These may be obtained by any biofuel source or process. Typical processes for their production involve transesterification of oils of vegetable origin (e.g. rapeseed oil, palm oil or soybean oil, etc.).

There may be an opportunity to economically increase the fuel extender level in the main fuel composition itself for a particular market where such additives may be produced or grown and consumed locally, reducing the need for transportation of the base fuel and/or additives. Under such conditions, amounts or treat rates of up to 30%, or up to 40%, or up to 50% of the main fuel composition are preferred, but in the case where the methanol source is crude methanol, total additives, including such fuel extender additives, at concentrations of up to 60% are specifically contemplated.

3. A combustion enhancer. It may also be referred to as a combustion promoter. One example of a combustion enhancer is a nitrated ammonium compound, such as ammonium nitrate. Ammonium nitrate is decomposed to nitrous oxide at 200 ℃ according to the following reaction:

NH₄NO₃＝N₂O+2H₂O

the nitrous oxide formed reacts with the fuel in the presence of water in a similar manner to oxygen, e.g.

CH₃OH+H₂O＝3H₂+CO₂

H₂+N₂O＝H₂O+N₂

CH₃OH+3N₂O＝3N₂+CO₂+2H₂O。

Other nitrated ammonium compounds that may be used include ethylamine nitrate and triethylamine nitrate as examples, but these nitrates are also considered ignition enhancers (cetane) rather than combustion enhancers because their primary function in fuel is ignition enhancement.

Other combustion promoters may include metal species or ionic species, the latter formed by dissociation in a pre-combustion or post-combustion environment.

4. The oxygen absorbs the oil. The oxygen-absorbing oil is preferably soluble in the water methanol mixture. Oxygen-absorbing oils have a low self-ignition point and also have the ability to directly absorb oxygen prior to combustion in an amount of, for example, 30% by weight of the oil. After evaporation of the surrounding water, rapid condensation of oxygen from the hot gas phase to the oil/solid phase will heat the oil particles more rapidly causing ignition of the surrounding evaporated and superheated methanol. Ideally the oil suitable for this role is linseed oil, at a concentration of about 1% to 5% in the main fuel mixture. If the additive is used in the main fuel composition, the fuel mixture should be stored under an inert gas blanket to minimize decomposition of the oil by oxygen. Linseed oil is a fatty acid containing oil. Instead of or in addition to linseed oil, other fatty acid-containing oils may be used. Preferred oils are those that are soluble in the methanol phase or miscible in methanol to produce a homogeneous, single phase composition. However, in some embodiments, oils that are not water/methanol miscible may be used, particularly if an emulsification additive is also present in the fuel composition.

5. A lubricity additive. Examples of lubricity additives include diethanolamine derivatives, fluorosurfactants, and fatty acid esters, such as biofuels that are soluble to some extent in the water/methanol mixture on which the main fuel composition is based.

6. A product coloring additive. The coloring additive helps to ensure that the fuel composition is not mistaken for a liquid beverage such as water. Any water soluble colorant may be used, such as yellow, red, blue colorants, or combinations of these colorants. The colorant may be a standard accepted industrial liquid colorant.

7. A flame color additive. Non-limiting examples include carbonates or acetates of sodium, lithium, calcium or strontium. The flame color additive may be selected to achieve preferred product color and stability of the final product pH. Engine deposit considerations, if any, may be taken into account when selecting the additives to be used.

8. An anti-corrosion additive. Non-limiting examples of corrosion inhibiting additives include amines and ammonium derivatives.

9. A biocide. Although biocides can be added, these are not generally required because the high alcohol (methanol) content in the main fuel prevents biological growth or biofouling. Thus, according to some embodiments, the main fuel is free of biocide.

10. And (4) a pour point depressant. Although pour point depressants may be added to the main fuel, methanol (and optional additives such as sugars added for other purposes) suppresses the freezing point of water. Thus, according to some embodiments, the main fuel is free of additional dedicated pour point depressants.

11. A deposit reducing agent. Non-limiting examples include polyol ethers and triethanolamine.

12. A denaturant, if desired.

A pH control agent. Agents that raise or lower the pH to a suitable pH may be used, which may be compatible with the fuel.

Additives and in particular those defined in clauses 1 and 2 above may be added to the main fuel as standard industry trade products (i.e. in refined form) or as semi-processed aqueous solutions (i.e. in unrefined, semi-refined or crude form). The latter option potentially reduces the cost of the additive. The use of such crude additive sources is provided that impurities in the crude form of such additives (such as crude sugar solutions or syrups, as one example) do not adversely affect fuel injector or engine performance.

According to some embodiments, the primary fuel comprises at least one additive. According to some embodiments, the main fuel comprises at least two different additives.

Ethers are indicated above as examples of ignition promoters and soluble fuel extender additives. In some embodiments, the ether may be present at a level of less than 20%, less than 15%, less than 10%, less than 5%, less than 3%, or less than 1% of the total fuel composition, regardless of the intended function. The amount may be greater than 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%. The lower and upper limits may be combined without limitation, provided that the lower limit is below the selected upper limit.

In some embodiments, the main fuel composition comprises an ether in an amount of 0.2% to 10% by weight of the main fuel composition. The ether is preferably one ether or a combination of two ethers.

By using ethers as ignition promoters and/or soluble fuel extenders in methanol-based fuels, a complete process for producing, delivering and using fuel compositions has been developed. In this example, the methanol-based fuel may be a non-aqueous fuel or a methanol-water fuel. Which is described in further detail below.

Ignition enhancer as fumigant

The fumigant used in the fumigation dependent method of some embodiments of the present invention comprises an ignition enhancer. In the context of the main fuel, the fumigant may also comprise further components, such as one or more of methanol, water and any of the additives listed above.

As noted above, an ignition enhancer is a material that enhances the ignition of a combustible material. One of the challenges in using methanol as a core fuel component in a main fuel composition for a compression ignition engine is the fact that methanol does not ignite as readily as other fuels. The ignition enhancer is a material that has good ignition characteristics and can be used to produce ignition, followed by combustion of the methanol (and other combustible materials) in the main fuel composition. The ignition characteristics of a potential fuel component are described by the cetane number (or alternatively cetane index) of that component. The cetane number is a measure of the ignition delay of a material, which is the period of time between the start of fuel injection and the start of combustion (i.e., ignition). Suitable ignition enhancers may have a cetane number greater than 40 (e.g., DME having a cetane number of 55 to 57). The cetane number of the ignition enhancer present in the fumigant should be considered in determining the relative amounts of the ignition enhancer and other components in the fumigant, as well as the amount, load and engine speed of the fumigant compared to the main fuel composition. The overall cetane number of the fumigant will be based on a combination of the proportional contribution of the components and the cetane profile, the relationship not necessarily being linear.

Some non-limiting examples of ignition enhancers that may be included in the fumigant include:

ethers, such as lower alkyl (being C1-C6 ethers), especially dimethyl ether and diethyl ether,

-an alkyl nitrate ester of an alcohol,

-an alkyl peroxide,

and mixtures thereof.

Dimethyl ether is a preferred high ignition characteristic ignition enhancer suitable for use in fumigants. Diethyl ether is another example of a suitable ignition enhancer.

The methanol in the main fuel can be catalytically converted to dimethyl ether. Thus, dimethyl ether can be catalytically produced from the main fuel composition stream, which stream is then fumigated separately into the engine to reach the main fuel composition (with the intake air). Alternatively, the fumigant composition comprising dimethyl ether may be provided to the engine owner as a ready-to-use fumigant composition by the fuel supplier. In another embodiment, a pre-fuel composition comprising methanol and up to 15% by weight of an ether ignition enhancer (e.g., dimethyl ether) may be produced in one location and transported (e.g., via a conduit) to another location for fueling a compression ignition engine. In some embodiments, the pre-fuel may also include water. At the end of the conduit, some or all of the ether ignition enhancer component in the pre-fuel can be separated from other components of the pre-fuel composition (particularly methanol, and other components having a boiling point higher than that of the ether). The separated ether component can then be fumigated into the compression ignition engine as a fumigant, separated from the remainder of the pre-fuel composition used as the main fuel composition, applied directly (especially if it contains water) or the composition can be further conditioned (e.g. water content) prior to use. The amount of ether ignition enhancer in the pre-fuel may be up to 10% by weight, or up to 9% by weight. The upper limit will depend on the choice of ether and temperature conditions. More details of CI engine power generation systems are given in the following sections.

The ignition enhancer (e.g. dimethyl ether) suitably comprises at least 5% of the fumigant and at least 10% of the fumigant, for example at least 15%, 20%, 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, 82%, 84%, 86%, 88% or 90% of the fumigant. It is generally preferred that the fumigant has an ignition enhancer content at the upper end of this range, and thus, in some embodiments, the ignition enhancer content is greater than 70% or more. For example, where the pure component is introduced from a warehouse or from a separate ignition enhancer derived from the recovery of the pre-fuel composition, the ignition enhancer may constitute up to 100% of the fumigant. The upper limit of such components will therefore be reduced when converted from the primary fuel by a catalytic reaction of the primary fuel (which contains components other than methanol from which DME is formed), or if impure high ignition quality components are produced or obtained from a silo.

The relative amounts of the components of the fumigant may be kept constant or may be varied over the length of engine operation. Factors that affect the relative amounts of the components in the fumigant include engine speed (rpm), level and variability of load, engine configuration, and the specific characteristics of each component of the fumigant. In other embodiments, the fumigant composition may remain relatively constant during different phases of engine operation, while the relative amount of fumigant (grams/second fumigated into the engine) compared to the main fuel composition (grams/second) injected into the engine is adjusted.

When it is desired to operate a CI engine with different fumigant compositions under different engine operating conditions (speed, load, configuration), the fumigant composition can be adapted (suit) by computer control of the fumigant composition or by any other form of control to vary the fumigant composition. The adjustment may be a floating adjustment (slipping adjustment) based on an algorithm that calculates the desired fumigant composition to match the prevailing engine operating conditions, or may be a step-wise adjustment. For example, under some conditions, a higher overall cetane index fumigant (e.g., 100% DME) may be fumigated into the engine at a high weight% for the operating fuel, and then the fumigant may be switched to a second composition containing a lower percentage of DME and some lower cetane index components. In another embodiment, the composition may be stable and the air/fumigant ratio may be varied.

The target% of the non-aqueous components of the fumigant other than the ignition enhancer is suitably no more than 40%, for example 5% to 40% or 10% to 40% or 20% to 40%, 30% to 40%. These percentages may be adjusted based on the cetane numbers of the other ignition enhancers and combustible components and the particular engine configuration. Additionally, in some embodiments, water may be present in the fumigant, either as a product of a conversion reaction (e.g., methanol to DME) or as a carrier from the aqueous reactor feed or added in a separate stream.

Examples of components that may be present in the fumigant in addition to the ignition enhancer include methanol, water, the additives listed above and alkane gases (typically straight chain alkanes, including lower alkanes such as C1-C6 alkanes, especially methane, ethane, propane or butane and long chain alkanes (C6 and above)).

In some embodiments, the fumigant comprises at least 60% of one component, one example being dimethyl ether. The amount of one major component of the fumigant may be greater than 62%, 65%, 68%, 70%, 72%, 75%, 78% or 80%.

The fumigant or secondary fuel may be obtained in pure form directly from the silo, or may be supplied to the engine as a fumigant in pure form after processing the primary fuel (by catalytic conversion of methanol to DME, followed by purification to produce a fumigant consisting of DME). Alternatively, the fumigant may comprise an ignition enhancer and further components after treatment of the main fuel (i.e. the fumigant is not in pure form) or further components from the warehouse. In such cases, the impurities are still compatible with the desired fumigant results, i.e., the fumigant may also include water and methanol, or may contain other materials (e.g., C1-C8 alcohols) that are compatible with the application.

The main fuel composition and fumigant may be supplied as a two part fuel, or may be delivered as a "cartridge" of two fuel parts. In this case, the fumigant may be described as the "secondary fuel component" of a two-part fuel, and therefore the description of the fumigant above also applies to the second fuel component. The primary fuel composition and the secondary fuel component may be pumped to separate storage vessels associated with the compression ignition engine.

Thus, according to one embodiment, there is provided a two-part fuel for operating a compression ignition engine, the fuel composition comprising:

-a main fuel composition comprising methanol and water, and

-a secondary fuel component comprising an ignition enhancer.

When using the two-part fuel, the main fuel is introduced into the combustion chamber of the compression ignition engine and the secondary fuel is fumigated into the intake of the compression ignition engine.

According to another embodiment, there is provided a method for fueling a compression ignition engine, the method comprising:

-supplying a main fuel composition comprising methanol and water to a first vessel in fluid connection with a combustion chamber of a compression ignition engine, and

-supplying a secondary fuel component comprising an ignition enhancer to a second vessel fluidly connected to an air intake of the compression ignition engine.

As described above, the secondary fuel may be prepared, in whole or in part, in situ by catalytically converting a portion of the primary fuel to an ignition enhancer. This is particularly suitable where the ignition enhancer is dimethyl ether.

The invention also provides the use of a two part fuel in the operation of a combustion ignition engine, wherein the two part fuel comprises:

-a main fuel composition comprising methanol and water, and

-a secondary fuel component comprising an ignition enhancer.

The invention also provides a pre-fuel composition comprising methanol and up to 10% by weight of an ether. The ether may be dimethyl ether. In some embodiments, the pre-fuel may also include water. As described above, the ether component can be separated from the remainder of the pre-fuel composition to be used as a secondary fuel component, and the balance of the pre-fuel composition can be used as a primary fuel composition. The balance may be used directly as the total main fuel composition (particularly if it contains water), or the composition may be adjusted to produce the main fuel composition, for example, by adding water. Thus, in this embodiment, the pre-fuel may not contain water, and water may be added after the ether is removed to produce the main fuel composition. In some embodiments, water may not be required for use in the main fuel composition when the fuel is used in one of the power generation systems described further below.

The present invention also provides a method of transporting a two part fuel composition (a first part comprising methanol and a second part comprising ether) from one location to another, comprising transporting a pre-fuel composition comprising methanol and ether from one location to a second location, separating the ether from the methanol to produce a first fuel part comprising methanol and a second fuel part comprising ether. The delivery may be by way of pumping through a conduit. The first location may be a methanol production plant location and the other location (the second location) is a location remote from the first location. The remote location is typically at least 1 kilometer away, and may be many kilometers away. The remote location may be an area where the compression ignition generator is used to generate electricity, or a cargo port or side rail of a train or any other suitable area where two-part fuel is required.

Details of engine operation

FIG. 1 illustrates a flow chart depicting a method of using a primary fuel 11-methanol/water mixture in a CI engine 10. The method includes fumigating an intake air stream 12 with an ignition enhancer 14, then introducing the fumigated air into a combustion chamber of the engine 10 via an ignition control 30, then introducing a main fuel 11 into the combustion chamber and igniting the main fuel/fumigated air mixture via compression ignition to power the engine.

The intake air 12 is fumigated with a fumigant 17 comprising an ignition enhancer 14. The fumigated intake air 12 is then injected into the combustion chamber before or during the initial stage of the engine compression stroke to compress the air before the main fuel is injected into the combustion chamber. The compression of the air raises the temperature in the combustion chamber to provide favorable ignition conditions for the main fuel as it is injected into the chamber during the final stages of compression.

Fumigating the intake air 12 with the ignition enhancer 14 further increases the temperature of the compressed air, making it more flammable at the point of fuel injection due to pre-combustion of the fumigant material, and the presence of decomposition products that assist in the methanol combustion.

The fumigation as described above causes pre-combustion to occur in the combustion chamber prior to fuel injection. The two-step ignition method (or "firing" operation) relies on the compression stroke of the engine piston to raise the temperature of the fumigated air to the ignition point. This in turn enhances the ignition conditions in the combustion chamber when injected at the end of the compression stroke, providing a sufficiently hot environment for the methanol and water fuel to undergo accelerated ignition at elevated temperature conditions, rapidly vaporizing the methanol and water in the fuel, and producing high thermal efficiency.

The temperature contribution of the fumigant in the steady operation of the engine at low water levels is from 50 ℃ to 100 ℃. For low water level fuels, at the main fuel injection point, this contribution results in a combustion chamber temperature comparable to that in known combustion ignition engines. As the water content level in the fuel increases, the amount of fumigant can be adjusted to counteract the cooling effect of the water. The resulting braking thermal efficiency is comparable to that of diesel fuel, with the net efficiency result depending on factors such as the size of the engine and its configuration.

Efficient and complete combustion of methanol and water fuels in this manner minimizes unburned or modified hydrocarbons and particulates in exhaust emissions, resulting in cleaner emissions. This is particularly evident in larger CI engines with lower speeds where the efficiency of the combustion method is maximized because sufficient time is allowed for two steps of starting and completing in the ignition operation.

The term "fumigant" in relation to intake air refers to the introduction of a material or mixture, in which case a fumigant containing an ignition enhancer is introduced into the intake air stream to form a vapor or gas, with the ignition enhancer being well distributed through the process. In some embodiments, small amounts of material are typically introduced by spraying a fine mist of the material into the incoming gas stream or injecting as a gas.

The ignition operation has the effect of preheating the intake air during the compression stroke. The nature of the water methanol mixture is that less sensible heat is generated in the reaction product after combustion, requiring heat to evaporate the water present. This means that more severe conditions can be accommodated at the injection point than in a diesel engine running on a hydrocarbon fuel, while remaining within the design limits of the engine. These harsher conditions are created by fumigant combustion or elevated air temperatures (by directly heating the air) and/or by using elevated pressures and temperatures through improved engine configurations (e.g., turbocharging or supercharging).

The amount of ignition enhancer may be controlled relative to the mixture of methanol and water contained in the main fuel to obtain conditions in the combustion chamber that produce ignition of the main fuel in a timely manner to deliver the best possible thermal efficiency from the engine. Without control of the ratio of ignition enhancer to fuel mixture, combustion may begin significantly before TDC (e.g., 25 deg.C to 30 deg.C before TDC), and thus, the use of the ignition enhancer may have a neutral effect and contribute little or no to the thermal efficiency of the engine. In preferred operation of the engine, ignition of the fumigant/air mixture is timed to retard combustion of the fuel as late as possible (to avoid unnecessary work of the power stroke of the engine) and to coincide with good combustion of the main fuel after injection. This means that the secondary fuel should be ignited before the injection of the primary fuel is initiated, but not too long before the energy contained in the secondary fuel contributes to the minimum or zero thermal efficiency of the engine.

Ignition of the main fuel may be controlled as close to the ideal time as possible at the ignition control 30 shown in fig. 1 by using one or a combination of the following ratios of ignition control:

1. the amount of fumigant introduced into the air intake relative to the main fuel is controlled.

2. The percentage of the ignition enhancer to other components in the fumigant is controlled (recognizing that water and other components such as methanol may also be present).

3. The above 1 and 2 are controlled according to the engine operating at high load (50% to 100%) or low load (less than 50%) in the rpm operating range of the engine.

While the relative amounts of fumigant and main fuel introduced into the engine (either through the intake or into the combustion chamber respectively) will vary depending on the engine operating conditions applied, it is generally desirable that the amount of ignition enhancer in the fumigant be a lower percentage by weight of the main fuel composition during steady state operation at medium or high load. For fumigants containing 100% ignition enhancer (e.g. DME), it is desirable that the relative amount of fumigant to main fuel by weight is at most 20%, at most 18%, at most 15%, at most 13%, at most 10%, at most 8%, at most 7%, at most 6%, at most 5% by weight. The fumigant level is preferably at least 0.2%, at least 0.5%, at least 1% or at least 2% by weight of the main fuel composition. These figures are all based on weight, assuming that the fumigant contains 100% of the ignition enhancer, and can be scaled to a reduced ignition enhancer content in the fumigant by weight. It may be measured with reference to the amount in grams/second introduced into the engine or any other suitable corresponding measurement method for engine size. An upper limit of about 10% or less (e.g., 8% or 7%) is also advantageous because a pre-fuel composition containing up to the desired ether as an ignition enhancer (e.g., 10%, 8%, or 7% ignition enhancer, respectively) can be delivered to the compression ignition engine, with the ignition enhancer flashed off and recovered in an amount corresponding to that required to run the engine with the same target level of fumigant. In other embodiments, there may be an increase in the level of fumigant (top-up) at the engine (e.g., from a separate storage of an ignition enhancer (e.g., ether)) to a higher level.

The ignition control 30 controls the ratio to control the nature of the intake air entering the engine 10. In particular, referring to fig. 1, the ignition control 30 controls the amount and relative proportions of air 12, fumigant 17, including the concentrations of the ignition enhancer 14 in the fumigant 17 and other components 19 in the fumigant 17.

With respect to fig. 2 above, the target% of non-aqueous components in the total fumigant/air stream other than the ignition enhancer may be no more than 40%, such as 5% to 40% or 10% to 40%, 20% to 40% or 30% to 40%, with the balance being an ignition enhancer, such as DME (which has a cetane number of 55 to 57). These percentages may be adjusted based on the cetane numbers of other ignition enhancers and the particular engine configuration. All percentages are by weight. Water may be present in any amount consistent with smooth operation of the engine, and such water may be produced from the fumigant, for example if produced catalytically from fuel, or as part of the ambient intake air flow into the engine, or may be added by other methods.

Fig. 1 illustrates a portion 13 of the primary fuel 11 being transferred from the engine 11 to the catalytic reactor 20 where catalytic dehydrogenation of methanol to DME occurs in the catalytic reactor 20. The DME produced is used as an ignition enhancer in the fumigant 17 for fumigating the intake air 12. Other embodiments described herein employ other techniques for producing dimethyl ether when used as an ignition enhancer for fumigants. In some such embodiments, DME can be produced at the methanol production and delivered to the engine location as part of the pre-fuel composition.

It is known to those skilled in the art that catalytic reactor 20 operates under standard industry conditions to perform dehydrogenation of methanol in methanol/water fuel. As shown in FIG. 1, the heat source for operating catalytic reactor 20 is exhaust gas 22 from engine 10 that is diverted through a heat exchanger (not shown) to heat the diverted portion of the main fuel in catalytic reactor 20. Exhaust temperatures may range from 200 ℃ to above 500 ℃, and are generally dependent on the load of the engine, i.e., higher engine loads will result in higher exhaust temperatures.

FIG. 1 shows engine exhaust 22 after being cooled after being diverted through a heat exchanger in the catalytic reactor, to be discharged to the atmosphere 28, after the catalytic reactor is powered with heat from the exhaust or other heat source as needed. Alternatively or additionally, as shown in fig. 1, the exhaust gas may be treated with a portion as a recycle fuel 32 (which has been treated by the condenser 25) that is condensed and recycled back to the main fuel, (where any cooling medium may be used), in the embodiment shown comprising a brine/water heat sink 34 (heat exchanger) suitable for use on board a ship. Other exhaust treatment steps using condensate or other means may also be employed to reduce target pollutants in the gas discharged to the atmosphere (28) to low levels. In another embodiment, components (e.g., any unburned fuel) may be adsorbed onto the active surface prior to desorption using standard techniques and included as the main fuel or fumigant component to further reduce contamination. Alternatively, a catalyst may be used to catalytically react any oxidizable material, such as unburned fuel, raise the exhaust temperature and provide other heat sources where applicable.

Additionally, if multiple engines are operating, for example, to generate electricity, the collected exhaust may be treated as a single stream for treatment/condensation with recycled fuel from the exhaust of one or more such engines.

The second fuel storage 38 provides fuel for direct use as a secondary fuel (i.e., the fuel is a fumigant containing an ignition enhancer) or for conversion to a secondary fuel by the catalytic reactor 20. The fuel in the secondary fuel storage 38 may be used as an alternative to obtaining the portion 13 of the primary fuel 11 converted by the catalytic reactor 20, or may be used in combination with the portion 13 of the primary fuel.

The poor cetane number characteristics of the methanol/water fuel (especially those with medium to high water content levels) can also be offset by preheating the main fuel and/or the intake air. Preheating can be achieved by a variety of techniques (including any one or combination of the following):

1. waste heat preheater-uses CI engine exhaust or other waste heat to preheat the intake air and/or the main fuel through heat exchange. A fan may be incorporated to optimize the pressure characteristics of the intake air through the engine cycle.

2. Supercharger/blower-or other air compression device driven by the engine to introduce intake air into the combustion chamber and heat the intake air by increasing air pressure.

3. Turbochargers, or other air compression mechanisms that are driven by engine exhaust or other waste heat to introduce intake air into the combustion chambers and heat the intake air by increasing air pressure.

4. The air is heated using direct methods, such as electrical heating by elements or combustion of fuel to produce the desired temperature increase. Such a method may be used during launch and at low engine loads.

5. Glow plugs (or hot bulbs) -draw heat into the engine cylinder.

Option 1 (without the fan) above will result in lower power output by the engine due to the lower mass flow of air (in 2 and 3, the mass flow of air is not reduced compared to options 2 to 3), but this loss of maximum power can be offset by higher combustion efficiency at hotter fuel injection points and lower demand for excess air compared to petroleum based diesel fuel. The compensating pressure fan can counteract the reduced air mass flow in the event of an increased air temperature.

The temperature required at the point of fuel injection and therefore the level of pre-heating required to ignite the water/methanol mixture depends on the amount of water present. At low to medium water content levels and for particular formulations, this can be achieved by air preheat temperatures of 50 to 150 ℃. However, for water content levels up to high water content levels, e.g., a 50%/50% water/methanol mixture, air preheat at 150 ℃ to 300 ℃ may be used.

In another embodiment, heating the primary fuel according to known techniques may assist the ignition process.

The warm-up option in combination with the medium to high water low methanol fuel changes the engine cycle from a constant volume during ignition and combustion and initial expansion period to a more constant temperature expansion that is directional (where the heat from the methanol largely vaporizes the water) over the time interval best suited to maximize engine performance.

Some adjustments to the above-described fuels and methods may be required to optimize the operation and efficiency of smaller CI engines operating at higher engine speeds (e.g., 1000rpm to 3000rpm, and higher). In addition to fumigating the intake air stream with a fumigant containing an ignition enhancer, the following operational aspects may be used alone or in combination for engines operating at higher rotational speeds:

● preheat intake air as described above, including by direct heating (from an independent heat source), heat exchange with exhaust gas, a supercharger, or a turbocharger.

● the combustion chamber is heated using, for example, glow plugs.

● preheat the main fuel feed.

● to the primary and/or secondary fuel are added additives that promote ignition and combustion of the fuel. Some of these additives are discussed below.

● select an appropriate water content level in the main fuel composition as discussed above. Such as low to medium water content level ranges.

● the water content level in the fumigant is selected to be a suitable level consistent with the engine configuration.

Additionally, these options may be used if desired when the larger CI engine is operating at a lower engine speed (e.g., 1000rpm or less).

CI engine power generation system

Using the methanol/water mixture fuel and associated systems (also referred to as methods) for powering a compression ignition engine described herein, a power generation system and structure may be developed to efficiently generate power at reduced emission levels, and which may also treat engine exhaust gases to capture heat and water from the exhaust gases and subsequently reuse or redirect them. The reuse or recycling of heat and water facilitates increased system efficiency and overall reduced waste and emissions. Heat and water redirection may find use in a range of unrelated applications, including heating and cooling sites/locations and regenerating water for use in communities or as part of other systems.

3A-6B illustrate examples of power generation systems incorporating the methods and fuels described herein for powering a compression ignition engine. It should be understood that the fuel shown in these methods is a methanol-based fuel, which may contain various amounts of water, and may contain water in amounts of 0% to 80%.

Fig. 3A and 3B illustrate a method for producing and supplying methanol fuel to an IC engine 111 (also referred to as a diesel engine) to produce output power, but which also includes reduced emissions engine exhaust treatment that utilizes engine exhaust recirculation water and incorporates Hot Water Loops (HWL)113A, 113B (see fig. 4A and 4B) to provide heat to local communities. The output power produced by the engine may also be used to service the community in which the power plant is located, for example to generate electricity for the community. Fig. 3A differs from fig. 3B in that fig. 3A illustrates a method of fumigating intake air into an engine, while the method illustrated in fig. 3B omits the step of fumigating intake air.

Fig. 3A and 3B illustrate a fuel production plant 101 and the remote supply of this fuel through a supply network 103. The fuel production plant may be a conventional methanol production plant that may use electricity generated from streams produced by conventional boilers in large remote coal yards 102. Such plants produce coal combustion emission characteristics. Alternatively, the power plant 102 may incorporate combustion engines that use the methanol fuel as described herein to generate the electricity needed to produce the methanol fuel. This may provide cleaner alternatives with lower emissions for those produced by coal plants.

Methanol-based fuels are produced in plant 101 and may contain primarily methanol, a methanol-water mixture, or a methanol-ether mixture, or a methanol-water-ether mixture. In one embodiment, the fuel comprises a mixture of "full fuel" methanol and DME blended at 90% to 99.5% methanol and DME, which is available directly to the engine 111 as a non-boiling liquid at atmospheric pressure. In a mixture of methanol and DME, DME is provided in a stable amount suitable for transport as a liquid and avoiding the conversion of ether to the vapor phase. This amount will depend on the pressure and temperature at which the fuel is delivered in the conduit 103, but is typically less than 10% of the total fuel amount and is in the range of 7% to 8%.

Alternatively, a fuel with a higher proportion of DME under pressurised conditions may be supplied. In another alternative, a high methanol content (e.g., chemical grade) fuel containing close to 100% methanol may be delivered for subsequent partial conversion to DME near the desired center (i.e., power plant). This form of pre-fuel composition containing a high percentage of methanol may contain about 0.2% or more of the water component. In another alternative, the fuel or pre-fuel delivered in the conduit may be a methanol-water fuel. The water in the methanol-water fuel may be associated with methanol (e.g., in crude methanol) or may be derived from excess water in a production zone that may be economically well utilized for this purpose. Depending on the materials built into the transport network and used to facilitate engine/process operation, the addition of some additive lubricity and corrosion promoters may be included in the transport fuel. The remote transportation of energy from large volumes of flammable liquids in pipes in area networks is a well established technology. Such infrastructure as pipeline 103 may also be used to deliver methanol fuel safely and economically to remote locations.

After delivery through conduit 103, the fuel reaches the power generation plant, which includes the compression ignition engine 111, the pretreatment platform 104, and the exhaust gas processors 113, 115, 116, 118. The fuel may be used directly as is in the engine 111, or may be subjected to optional pretreatment to operate safely and reliably within the plant operating envelope. For system integrity reasons, a reservoir that starts and shuts down the fuel may also be contemplated, for example, the ether component may be stored.

At the pre-processing stage 104, the fuel may be separated by flashing into two rich phases, a methanol rich fraction 107, and an ether rich fraction 105, such as DME. DME is particularly suitable for this flash evaporation process due to its low boiling point. Low level waste heat from engine exhaust of hot water streams at temperatures of 50 ℃ to 60 ℃ can be used to flash separate low boiling DME from methanol. In some embodiments, the methanol-rich phase may contain a small amount of DME, with most of the DME being flashed off. In other embodiments, a high proportion of DME may remain in the liquid phase, with only sufficient DME to ensure good and complete combustion being vaporised and used as fumigant 105. For example, if the fuel from the production plant contains 7% DME, 5% of it may remain in the liquid phase, with 2% being used as fumigant 105 for addition to the heated combustion gas 110 into the engine 111.

The pretreatment may include conversion options to supplement the supply of DME or other fumigant. Alternatively, the required amount of ignition improver, for example DME, may be obtained from a depot. Other such agents are also possible, such as DEE and other ignition promoters described herein.

The pretreatment platform may also include a processing portion that delivers fuel to not only separate DME to be used as a fumigant, but also to generate excess DME for use as a liquid fuel component for other processes. For example, the remaining DME may benefit the nearby communities by providing the HWL with the remaining heat. Alternatively or additionally, the DME may be integrated with a power plant process. Methanol fuel can also be removed from the power generation system (either before or after processing) and used for local chemical production.

It is also possible to transport it to a crude methanol production plant, saving investment costs and operating costs in upstream production plants. Such a fuel feed for a power generation plant would be suitable for the above options: part of the crude methanol is separated for DME production and the remaining fuel is put into the engine. In terms of energy and investment costs, this option would replace the distillation unit of the production plant 101 in which most of the product is distilled and undergoes "overhead" (at a lower amount) at the power generation plant in much smaller units. This option may also be used in demand centers near the local DME, i.e. near the power generation plant.

The fuel pre-treatment at the pre-treatment platform 104 may also heat the methanol fuel 107 prior to entering the engine, using cold water from the venturi scrubber 115 return line (exiting the pre-treatment stage 104) as the irrigation quality water 106. The cooled irrigation quality water 106 may be mixed with condensate from the condenser 116 and, if necessary, the condenser may be used to ensure an acceptable effluent temperature.

In the example shown for power generation with HWL, 1MW and above of power can be generated using a diesel engine. This does not exclude powers below 1MW, which can be used for smaller users and with low NOX, SOX and particulate results. Diesel engines are particularly suited for post-combustion processing because they provide the driving force for the air pressure required to move the exhaust through the cleaning and heat exchange equipment with only a small expenditure on engine efficiency.

The nature of some of the fuel mixtures described herein means that large diameter pistons are preferred over smaller pistons due to the inherent increased thermal benefits of engine size. The larger piston also reduces the risk of injected fuel affecting the piston wall, ensuring that the fuel burns properly and does not interfere with the lubricant film.

While the experiments further mentioned below show fuels tested in engines operating at greater than 1000rpm, as previously suggested, the fuels can be successfully used in lower speed engines typically operating only below 100rpm up to 1000rpm, a range generally described as a low to mid speed range. This speed range is more commonly described as a low to mid speed range. This range of rotational speeds allows the volatile ignition improver more time to enter the vapor space as a vapor and begin its chemical reaction with the hot pressurized air during the compression stroke. A greater time margin during the combustion period will allow the fuel to burn more completely and reduce the level of unburned fuel and other components in the exhaust gas emitted by the engine. A larger time window will allow more time for the fuel in the cylinder to burn completely through contact of water oxygen molecules, allowing a lower lambda to be used, which increases the concentration of water in the engine exhaust.

The mixture of methanol 107 and water 108 entering the engine 111 may be preheated by mixing it with air 100 to generate power in the engine 111 and, in the example illustrated in fig. 3A and 3B, the mixture is preheated by engine exhaust gas through condenser 116. Suitable preheating temperatures may be from 40 ℃ to 50 ℃. The water in the fuel may originate from a reservoir or from water circulated through the condenser 116 from the exhaust (which is explained in more detail below).

Treatment of the exhaust gas includes passing the engine exhaust through a catalytic converter 112 using a catalyst targeted to CO2 and oxides. This will cause marginal heating of the exhaust gas, which may be used in the HWL or in other methods described further below in connection with fig. 5A, 5B, 6A, and 6B. The catalytic converter 112 also reduces any fuel or combustion products to an appropriate level. Final stage activated carbon or the like may optionally be used for cleaning. In addition, the methanol fuel described herein burns cleanly with low soot, which promotes catalyst performance.

The HWL carries heat through a loop of pumped water to a locally based destination, such as a residential area. Fig. 4A and 4B illustrate the HWL supply line 113a and return line 113B at the HWL heat exchanger 113. The utilized thermal by-products from the power generation process can be used to provide low cost heating for residential and commercial areas. The water pumped through the HWL is heated by the HWL heat exchanger 113 downstream of the catalytic converter 112. The heat exchanger 113 is a standard unit that operates at a temperature of 40 ℃ based on the return of the HWL, and the design schedule temperature (dispatch schedule) to the HWL is 80 ℃. In terms of required surface area, a cooler HWL return temperature and an efficient exchanger design will ensure adequate cooling of the exhaust.

The exhaust gas treatment additive is added at the caustic injector, which injects any caustic chemicals and other suitable acidic neutralizing agents into the exhaust gas for the desired result. For example, to remove acidic compounds from the final exhaust, a low dosage of alkaline liquid (e.g., 50% caustic soda and water) is injected into the exhaust stream for neutralizing trace amounts of acid and controlling the pH of the irrigation water flowing through the plant. The final pH is controlled to a level that best meets local conditions.

A venturi scrubber 115 or other suitable mixing device is shown downstream of the HWL exchanger 113. This unit has several functions, the first of which is to intimately mix the exhaust gas with a circulating water stream, which acts to cool the exhaust gas from 85 ℃ to 90 ℃ exiting the HWL exchanger to 55 ℃ to 60 ℃ exiting the venturi scrubber. Such cooling will produce condensed water from the exhaust gas and collect the particles that can be treated using known methods, or ultimately form part of the final irrigation water that leaves the plant for return to the ground. The de-acidified and cleaned vent gas leaving scrubber 115 produces a higher purity vent gas leaving the final condenser.

Water is pumped between the venturi scrubber 115 and the fin blower heat exchanger 100. A fin fan heat exchanger 100 or other suitable device takes heat from the exhaust gas through a venturi scrubber and blocks (reject) the heat from reaching another air/liquid exchange with the air being driven through the heat exchanger 100 by one or more fans, one advantage of the thermal block of this approach is that the heat is blocked at low temperatures and, therefore, has no major effect on the overall efficiency of the process.

As an alternative to discharging heat into the atmosphere, heated air from the finned fan exhaust may be used directly as heated combustion air 110 to the engine, in which case some pressure may be applied from the fan to counteract the heating effect on the air mass flow. Another alternative to discharging heat to the atmosphere is through a cold water basin or other water system capable of dissipating large amounts of heat in a dependable and environmentally acceptable manner.

Fig. 4A illustrates the final large exhaust/combustion air exchanger, i.e., condenser 116, recovering water in a high water recovery system. In systems where high water recovery is not necessary, the condenser 116 is not included. Fig. 4B illustrates a reclaimed water recovery system similar to that of fig. 4A, but with the condenser 116 omitted.

A final (optional) condenser 116 cools the exhaust from the venturi scrubber 115 from about 50 ℃ to 60 ℃ to an ambient temperature of about 5 ℃ to 20 ℃. When the temperature is decreased by this amount, the produced water recovered from the plant increases significantly. Condensate from condenser 116 may optionally be used in a power generation process, in addition to producing water for irrigation or reuse outside of the power generation plant.

The pretreated fuel may be injected into the condensate to reduce NOx formation and associated acidizing events in downstream equipment (e.g., HWL exchangers). The condensate may also form a source of water to be used for combustion of the particular fuel blend, as an alternative or as stored water. In addition, the higher grade water from the condenser may be further processed into potable water, or may be added to irrigation quality water produced by the venturi scrubber and circulated between the venturi scrubber 115 and the fin fan heat exchanger 100.

The heat from cooling the exhaust gas is not waste heat, but may be exchanged with the intake air entering the engine 111. In addition to the benefits of recycling waste heat and water to the fuel required and emissions produced in the process, the heat recovery of water tends to also stabilize engine operation. Cooler intake air entering the engine allows more heat to be recovered.

Fig. 3B differs from fig. 3A in that it illustrates a method for producing and supplying methanol fuel to engine 111 without fumigating the intake air with an ignition improver. Methanol fuel from the production plant 101 is delivered through the pipeline infrastructure 103 for direct use in the engine 111, where the intake air 110 is preheated. No pretreatment is required to flash separate the ether from the delivered fuel because no fumigant is required. However, pretreatment may still occur to prepare fuels for combustion and/or to separate ethers for separation purposes outside of the power generation plant. It should also be understood that in connection with fig. 3A, the step of preheating the inlet air with the rejected heat is not necessary and may be omitted. However, it is useful to use the exhaust heat and the recycled exhaust particulates to improve engine efficiency and reduce emissions. Alternatively, water from the venturi scrubber to the fin blower may in principle be used for the purpose of heating the intake air.

In the method illustrated in FIG. 3B, the intake air may be preheated by a variety of methods, including using heat transferred from the exhaust gas, such as by the condenser 116 or heat obtained from the exhaust gas early in the post-combustion process (e.g., during the catalytic conversion stage). Alternatively, the intake air is preheated using other techniques described herein, including direct heating with an electric heating element, glow plug, and indirect heating, such as through a supercharger or turbocharger.

Fig. 5A and 5B illustrate how the concept of generating power using the techniques and fuels described herein can be used to power a rail vehicle. Reference numerals in fig. 5A and 5B correspond to the same numbers and entries used in connection with fig. 3A and 3B. Any pre-treatment 104 of the fuel is the same as the use of the fuel by the engine 111. The first heat exchanger 120 uses ambient air to cool the exhaust gas and heat the combustion air 110 after exiting the catalytic converter 112 through the first heat exchanger 120 to cool the exhaust gas.

The treatment of exhaust gases on a rail vehicle is different from the HWL process which separates water from other exhaust materials. The exhaust gas leaving the catalytic converter passes through an active alumina water absorption cycle 121 and an active alumina water evolution cycle 122 to produce clean hot and dry exhaust gas to the atmosphere, while water is recaptured from the exhaust gas by a water condenser 123. The recaptured water may be supplied back to a pre-treatment stage or for non-portable rail vehicle use. The cooler dry exhaust gas exiting the activated alumina cycle may be used by the second heat exchanger 124 to provide heating or cooling on the rail vehicle.

In one embodiment, the production of fuel at the methanol plant 101 can potentially cause two components to be stored in rail vehicles: (1) a water-methanol mixture designed to provide the correct NOX/performance results, and (2) separately stored fumigant components under pressure. The rail weight loss is not significant compared to the shipping weight loss.

Fig. 5B, similar to fig. 3B, illustrates a rail vehicle power generation method that does not use fumigant and relies only on preheating. The same comments made on the advantages of the HWL method without using fumigants apply to the method described in connection with fig. 5B.

Fig. 6A and 6B illustrate the concept of a power generation method for offshore (e.g., on-board) purposes. Similar to the HWL power generation method example, a methanol production plant sized according to the ship may be provided on the ship to supply one or more engines 111 powering the ship with methanol-based fuel. Similar to the above example, fig. 6A illustrates a method of using a fumigant ignition enhancer in intake air, while fig. 6B illustrates a method without a fumigant. Instead, the method may include intake air that is not preheated or intake air that is preheated.

The first heat exchanger 120 on the marine vehicle uses cooler ambient air to cool the exhaust gas. A portion of the exhaust gas may be recycled into the heated combustion air 110. The remaining cooled exhaust gas is then sent to the desalter 125 and other heat exchange equipment to maximize exhaust heat recovery for the needs of the vehicle (e.g., vessel and vehicle heating). The desalter uses seawater readily available for marine vehicles.

When used in the above applications, a general advantage associated with the methods and fuels described herein is that it enables the delivery of several benefits for energy and resource constrained communities and locations. Particular advantages include:

● develop remote resources that may remain unexplored due to inadequacies (e.g., high sulfur).

● provide seamless option for efficient biomass CO-processing for CO reduction₂。

● the earliest co-use of biomass will extend the life of existing resources.

● may also incorporate other renewable resources such as wind and sun.

● provide electrical power to a demanding center based on Combined Heat and Power (CHP) or combined cooling heat and cooling (CCHP).

● is in fact cleared byAll non-CO produced during the generation of electrical energy₂A contaminant.

● capture hydrogen from resources to the greatest extent possible and convert these resources to water for use in demanding centers (1 part hydrogen conversion by weight reacted with oxygen: 9 parts water). Under such an arrangement, fossil fuel resources can also be considered in part as water resources with a potential "free-carry" role, as in any case the fuel delivery mechanism will absorb its own distribution costs. The water is treated with activated alumina or other suitable absorbent material or technology to remove breakthrough through the catalytic converter (which treats hot engine exhaust).

● provide waste heat to local communities by cooling the exhaust air through a Hot Water Loop (HWL) and exchanging this primary source of thermal energy with a local heat demand centre for heating or cooling purposes. The clean exhaust gas obtained by utilizing the techniques described herein allows power generation to approach the market, a feature that is not typically achievable for power generation, particularly for coal combustion.

● efficiently recover water and heat. Alternative heat transfer methods may be used, with increased recovery but higher cost, and optionally the combustion air may also be heated by circulating water, for example, before the fin fan cooler (in the example of fig. 3A and 3B).

● high water recovery rates can be achieved, about 0.7 to 1 tonne of irrigation water per tonne of methanol consumed, or even higher if not objectionable based on economic and engineering background.

● provides pH neutral irrigation water for direct use by the local community.

● provides a water washed effluent in which the acid is neutralized and particulate matter is removed to low levels. Other pollutants in the exhaust gas, such as SOX and hydrocarbons, will also be low.

The techniques described herein with water production, HWL heat integration, and emissions results will be costly in terms of engine efficiency, however, in many cases it is desirable that this aspect can be offset by supply chain benefits and the benefits mentioned above.

Examples

Example 1: experimental project for researching methanol-water fuel composition for compression ignition engine

1.1 general description

The report summarizes the results obtained during the fulfillment project conducted by melbourne university with respect to the performance and engine output emissions of different methanol-based fuels in compression ignition engines.

The fuel tested was a mixture of methanol, water, dimethyl ether (DME) and diethyl ether (DEE). Because dimethyl ether is not a common compression ignition fuel, two ignition improver systems are used. The first ignition improver system consisted of an inlet air preheater. By heating the engine intake air to at most 150 ℃ (safety margin imposed), a higher temperature is reached near the end of the compression stroke, at which point the main fuel charge is injected. In some cases, these temperatures are high enough that compression ignition of the injected fuel occurs.

A second system for facilitating ignition involves the continuous injection (i.e., fumigation) of gaseous dimethyl ether (DME) into the intake of an engine. Because DME has a lower ignition temperature and a higher cetane number, DME auto-ignites as the air/fumigant mixture compresses during the compression stroke, releasing thermal energy that can ignite the primary fuel charge.

The test was performed on a modified 1D81 Hatz-single cylinder diesel engine mounted on a mobile/absorption dynamometer device built indoors. In the unmodified state, the self-igniting air-breathing engine produces at most 10kW of shaft power from a single cylinder of about 667cc volume. It is highly likely that the absolute performance of all fuels tested will be better in larger engines, since it is generally known that engine peak efficiency increases with engine size in the engine zone due to basic physical laws.

Thus, it is believed that in existing test items, engine performance in terms of non-diesel fuel should be viewed relative to the results of filling the engine with diesel fuel. In particular, if comparable or better performance is obtained with a given alternative fuel relative to the diesel of the engine, the relative performance may also be obtained on larger engines. Of course, maximizing the absolute performance of a given fuel on a given engine requires further optimization, and it should improve engine performance.

The general observations of this experimental project were as follows:

1. fumigated engine testing

These results show that under more efficient operating conditions, the fumigated engine produced comparable efficiency, lower NO emissions and much lower particulate emissions compared to diesel engines.

2. Heated air intake test

These results show that engine-out NO emissions are comparable to diesel engines. As the fumigated engine was operated, much lower particulate emissions were again observed compared to diesel engines. In this operating mode, further work is required to improve the efficiency of the engine.

1.2 Experimental methods

The test was conducted on a modified 1D81Hatz diesel engine-mounted mobile/absorption dynamometer apparatus built indoors. Figure 10 shows a method and instrument diagram of the apparatus. Unmodified engine specifications are detailed in table 1 below. These specifications were not changed during engine testing.

The improvement to the engine consists of:

● replace mechanical fuel injectors and fuel pumps with solenoid driven injection systems and separate fuel pumps and injection systems. A common rail diesel injector, electrically commanded, is used to provide fuel to the system. The injector (Bosch, model0445110054-RE) delivers significantly higher volumetric flow on an unmodified engine than the injector, so that the fuel with the highest water content in table 2 can be delivered while achieving the same air/fuel ratio as diesel and pure methanol fuel.

For the engine, the injector is oversized and should therefore result in a significant reduction in engine performance, even when operating on the same diesel fuel as the unmodified engine. Thus, the appropriate references for testing the alternative fuels listed in table 2 are the same, and the improved system is run on diesel, with the results listed in tables 3, 4 and 5. It is expected that further testing (particularly with fuels having lower water content) will result in the use of smaller injectors and thus significantly improve engine performance.

As shown in fig. 10, the fuel is mixed into the pressurized storage vessel so that DME is not converted to the vapor phase prior to injection into the engine. During the test, the container was always 5 to 10 bar. The liquid fuel leaving the tank was then pressurised to 800bar by a Haskel-air driven pump before injection into the engine. A high voltage battery was used to ensure that the fuel line pressure remained constant during the test.

Fuel flow was measured by suspending the pressurized storage vessel above a load cell and measuring the rate of change of the mass of the vessel during each test.

● extension of intake manifold (inletmatic)

The feed gas preheater was connected to the DME fumigation inlet. Both systems were used as ignition promoters for the main fuel charge.

● extend the exhaust manifold to connect all emission analysis systems.

● Kistler piezoelectric transducer.

The cylinder head of the engine is mounted to record the in-cylinder pressure.

● ShellHelixRacing10W60 oil was used for all tests.

It is a synthetic oil.

Exhaust emissions are analyzed using a plurality of independent systems.

● MAHA particulate matter meter

The apparatus provides a weight measurement of particulate matter in the engine exhaust.

● BoschUEGO sensor

This is the generating means that measures the air-fuel ratio. Although the device has been produced for hydrocarbon fuels, it has been shown to function well for all fuels tested, except those with water content greater than 50%, compared to the air-fuel ratio measured by ADS9000 emissions bench (bench) (fig. 4).

● ADS9000 emission stand

The device measures engine emissions of NO. Before sampling, the exhaust gas sample flows through an unheated line and a water trap, and therefore, the water content of the sample gas should be close to saturation at ambient conditions. The ADS9000 is corrected using the calibration gas and gas separator in terms of measured quantities before and during the test project.

● GasmetFTIR emission analyzer

The apparatus was calibrated using appropriate calibration gas and zeroed with high purity nitrogen according to the supplier's instructions.

Each fuel was tested at a steady state speed of 2000rpm and a lambda value of 2 (i.e., 100% air excess). The unmodified engine was operated at a lambda of about 1.5. Because the first test with pure methanol at λ 1.5 resulted in engine seizure (in one example, due to premature injection), lean operation was selected. No further engine seizure was experienced at λ 2.

The overall test engine protocol is as follows.

1. The heated inlet air operates.

The inlet gas was first raised to 150 ℃.

The injection duration is set to a value of 2 and the start of injection is set to top dead center.

The heating controller then reduces the intake air temperature while the engine is running until the forced engine torque (posiveenginetorque) no longer continues. The heater intake controller then sets the inlet temperature to a higher level than when the operation is stopped.

The start of the injection is then synchronized with the dynamometer controller, which maintains a constant engine speed, until the engine torque reaches the so-called "Maximum Braking Torque (MBT)". MBT is the most efficient operating condition for constant engine speed and air/fuel ratio.

The resulting injection time (start and duration) and other measured quantities were recorded for this operating condition.

2. The fumigated inlet air operates.

The engine was set up under smooth running conditions with high DME flow.

The main fuel injection duration is set to a lambda value of 2 and the injection start time is set to top dead center.

The DME flow is reduced while the primary fuel flow is increased to maintain a constant lambda until the engine torque is maximized.

The injection start timing is then started until MBT timing is reached, while main fuel flow continues to be adjusted to maintain lambda, if needed.

The resulting injection timing (start and duration) and other measured quantities are recorded for this operating condition.

3. Diesel fuel operation

The injection start time is brought to MBT while λ is kept at 2 by the injection duration.

The fuel specification is as follows.

● methanol, 99.8% + purity

● deionized water, 99.8% + purity

● dimethyl ether (DME), 98% + purity

● Ether (DEE), 98% + purity

1.3 results

The results of the test work are shown in the table below.

Table 1: description of the unmodified Engine

Table 2: the fuel schedule tested (at 150 ℃ C. those shown in bold do not produce net work output even with induction)

Table 3: diesel fuel performance data

Table 4: diesel ADS9000 emissions data

Table 5: performance data obtained by steaming with DME

Table 6: performance data obtained with heated inlet air

Table 7: MAHA and ADS9000 (calculated wet bleed) emissions from DME fumigation

Table 8: MAHA and ADS9000 (calculated wet exhaust) emissions from heated inlet air

^＊Failure to obtain these entries due to pressure sensor failure during testing

Table 9: combustion analysis data obtained with DME fumigation

Table 10: combustion analysis data obtained with heated intake air

1.5 other test work

Additional testing work was conducted to develop additional fuel and fumigant combinations, and the results of these tests are summarized in tables 11 and 12 below. Note the following:

● Overall, the engine efficiency at 1000rpm is lower than the same or similar fuels at higher engine speeds. This is based on the fact that the unmodified Hatz engine has peak efficiency at about 2000rpm and is desirable. When used in larger engines designed for peak efficiency at lower rpm, the efficiency of using fuel will be improved.

● NO emissions using the ADS9000 device are not shown due to failure of the sensor during this test project.

The fuel injector failed during test number 25. The data recorded for this test still seemed reasonable, since failure occurred late in the test, and is therefore contained in this appendix. Note the comparative performance of runs 25 and 27, which have very similar main fuel compositions, except for the additives.

Table 11: performance data obtained by steaming with DME

Table 11 (next): performance data obtained by steaming with DME

Table 11 (next): performance data obtained by steaming with DME

Table 12: performance data obtained with heated intake air

Table 12 (next): performance data obtained with heated intake air

Table 12 (next): performance data obtained with heated inlet air

1.5 comparative Table of volume% to Mass% of Fuel composition

The tables of test results given in 1.1 to 1.4 above are based on the relative amounts of the components in the main fuel composition measured by volume. Tables 13 and 14 below enable conversion between volume% and weight% of the fuel composition.

Table 13: comparative table of wt% to mass% -Fumigation

Table 14: comparison of% by volume and% by mass Table intake air preheating

1.6 observations of test results reported in sections 1.1 to 1.5

Water and ether plus DME fumigant:

the work reported hereinabove indicates that water has some key properties that make it a useful additive to methanol fuels:

1. if combustible methanol fuel is injected up to a point, the efficiency does not decrease but increases to an optimum point and then decreases as the proportion of water increases continuously. Applicants hypothesize that the increase in efficiency may be due to a combination of factors such as:

a. in the heating (e.g., infrared IR) zone, water has broad spectrum properties such as emission and absorption coefficients superior to methanol, which assists in the absorption of the emitted heat into the droplets of mixed fuel and water as the methanol evaporates from the droplets at an accelerated rate, since methanol will first share this higher heat absorption rate and evaporate.

The emissivity of water reported in the literature is 0.9 to 1.0, i.e. close to infrared-illuminated black body, while methanol is less than half the value close to 0.4.

b. The thermal conductivity of water is greater than that of methanol.

c. The thermal diffusivity of water is greater than that of methanol.

d. The above points b. and c. will cause a greater transfer of heat in the water droplets present, again accelerating the conversion of liquid phase methanol to gas as the methanol concentration decreases with droplet shrinkage.

Taken from Thermochimicaacta492(2009) on pages 95 to 100

2. The work reported hereinabove provides evidence of the availability of water methanol fuel by demonstrating that it promotes smooth operation with the proper amount of ignition in the fumigant, even when operating at high levels. From the data shown in fig. 7, which is from the work reported hereinabove, it is shown that a peak in braking thermal efficiency is obtained when the water content is about 12% to 23% by weight of the main fuel composition. The water content of the elevated BTE zone is 2% to 32% and the optimal zone obtained with DME fumigant is approximately 16% to 18%. This is an unexpected result. It is unexpected that injecting such high water content levels into the combustion chamber will allow the compression ignition engine to operate with acceptable operation in terms of COV for IMEP. (variable coefficient of mean effective pressure shown)

From the experimental data reported above, in most cases the low BET performer (performer) was undiluted methanol, good performance was obtained with a mixture comprising DME in the weight range of 4% to 9%.

As the water content of the fuel containing the aforementioned substantial amount of DME exceeds about 30% by weight, the efficiency drops to a level consistent with the fuel being combusted without the presence of water.

It should be noted that fuel with about 70% water is burned in the engine, even at half the efficiency due to the higher waste water content.

FIG. 8 provides a schematic of the ether content (wt%) of the primary fuel and the resulting BTE of the fuel. Brackets (}) are used to mark points associated with the use of diethyl ether as the ether component in the fuel composition, while the ether used in the other plots is dimethyl ether. FIG. 8 shows that the introduction of 4% DME into the liquid phase at about 16% water content causes an increase in BTE of about 1.5% compared to the case of undiluted methanol. Generally, the results provided by using a certain amount of ether in the box shown by the dashed line provide advantages to the main fuel composition. Increasing the ether content beyond the 10% level (i.e., outside of the box on the right side of the figure) introduces additional cost without corresponding process improvements or advantages.

At low water levels, the benefit of 16% DME is less compared to 4%, with 4% DME being superior to 16% DME at water contents above about 6%.

About 8% by weight of DME has a BTE slightly higher than 4% DME over the entire water content range, with the difference averaging about 0.3% to a maximum of about 36% water in the fuel.

At lower water content ranges, diethyl ether (DEE, bracketed points) in the fuel shows a weaker BET where the performance is similar to neat methanol, but as the water content in the fuel rises to greater than about 25%, about 8% DEE improves its performance to match those of DME.

In terms of braking thermal efficiency, DEE may not be selected before DME in methanol-water fuel unless there are other reasons, such as volatility or vapor pressure dominance (prevailed).

Effect of water and fumigant on NO:

in a fumigated environment where a coolant such as water is applied, it cannot be predicted that a reduction in NO can be obtained, and the extent of NO reduction cannot be predicted. The test work showed that as the water content level increased, NO was greatly reduced, as shown in fig. 9, showing a low pressure of 0.2 g/kw-hr at 36% water by weight.

FIG. 10 provides another illustration of the effect of increasing water content on NOx in the exhaust. The 4% and 8% DME lines show the best response to NOx formation, even at high inlet temperatures. The same trend is seen with fumigation, with NOX reduction with increasing water content levels, 16.5% DME and 8.8% DEE show higher levels of NO compared to the low DME case. Heating operation without water produces higher NO compared to diesel fuel without preheating.

As is apparent from the above data and the figures, an advantageous operating regime involves using a main fuel composition comprising methanol and 20% to 22% by weight water and 4% to 6% by weight DME in the main fuel composition, while fumigating. The fuel will achieve good efficiency and low NO. As detailed in other sections of the present application, the desired fuel operating region can be further expanded with acceptable operation of the CI engine.

In contrast, fuel in the same engine gave 4.9 g/kw-hr at λ 2 and 2000rpm (in these figures, λ and rpm for all fumigated tests).

Fumigant:

the use of fumigants (or fumigants) has not previously been considered for complex fuel compositions, particularly for fuel compositions comprising water and methanol and optionally other additives (e.g. DME). Of course, no layer reports commercial use of such technology. This may be due to the fact that such fuels are not considered likely to work well at all due to the low heating value of methanol, which is further impaired by mixing it with high latent heat diluents such as water. The use of fuels containing large amounts of water components is also counter-intuitive, as water is often used to extinguish fires rather than to aid their combustion.

To investigate this field, a single cylinder engine of similar capacity with a cylinder of 5 litre V8 engine was used, fitted with a larger injector to overcome the low heating value per litre of some of the fuel to be tested.

These larger injectors have the effect of reducing engine efficiency, but as a comparison between fuels, provided that the same conditions (mirrorconditions) apply, engine test experts acknowledge the validity of the comparison.

Oversized injectors were required in the particular operating conditions tested and the engine was run at high rpm due to the small engine size, but further work allowed these factors to be improved with the result that the relative amount of fumigant (ignition enhancer) injected into the engine intake was reduced. The experimental work carried out to support this application was carried out at 2000rpm and 1000rpm, the latter being the lowest operable speed of the Hatz engine for this project.

Example 2: fumigating 30 to 70% of water and methanol fuel

The introduction of a fuel comprising 70% methanol and 30% water into a compression ignition engine is schematically illustrated in figure 1.

Different fumigant compositions can be used for fumigating intake air into the engine at different operating stages of the engine (cranking, steady state at low load, steady state at 50% to 100% full load, idle, etc.).

At start-up and initial idle, a greater weight% of fumigant relative to the main fuel fumigates into the air intake. One suitable fumigant contains 100% DME for this phase of operation.

The% amount of fumigant and/or the% amount of ignition enhancer in the fumigant may be reduced after the engine is running and the load/rpm is increased.

As engine speed and load increase to full load, the wt% of the fumigant composition relative to the main fuel may decrease, for example to 7 to 9% by weight of the main fuel (100% DME in fumigant, or dry basis (db)) (see figure 2).

This allows the engine to run against the presence of water at 30% in the main fuel composition.

Example 3: 5% to 95% water to methanol fuel with fumigant

Example 2 was repeated but using a 95% methanol to 5% water composition. Due to the higher methanol content, the wt% of fumigant or% DME in the fumigant can be reduced compared to example 2, for example to 2% to 3% of the feed at full load (e.g. 100% DME) at different stages of engine operation.

Example 4: 1%: 99% water: methanol fuel with fumigant

Example 2 was repeated but using a 99% methanol to 1% water composition. Due to the higher methanol content, the wt% of fumigant or% DME in the fumigant can be reduced compared to example 2, for example to 2% to 3% of the feed at full load (e.g. 100% DME) at different stages of engine operation.

Example 5: fumigating and heating method using 30%: 70% water and methanol fuel

Example 2 was repeated, but the combustion gas was preheated to 140 ℃ using the method described previously. This change reduced the fumigant by the required 2% to 3% by weight compared to 7% to 9% of example 2.

Example 6: fumigating and heating method using 74%: 26% water and methanol fuel

Example 3 was repeated but using a 26% methanol, 74% water fuel composition. The fuel composition is suitable for use in marine applications-for operating marine CI engines. In this case, seawater may be used as a heat sink if needed to achieve the desired level of condensation from the exhaust gas. Under aquatic conditions, to ensure the safety of the enclosed space by the presence of a spilled amount of a non-flammable gas phase, the water content level in the fuel composition is about 74% (or more), with 26% (or less) of the fuel being methanol. This high water content avoids the risk of ignition causing combustion in the engine compartment.

This fuel is an example of a composition that can be pumped into a main fuel storage vessel for use (i.e., 74% water in methanol composition). Alternatively, a premix having a lower water content level (compared to the composition in use) may be pumped into the storage vessel, the water content level being increased by water dilution of the premix eventually between storage and filling into the engine. The water source may be any water source, and may be, for example, recycled water or desalinated water. This option has advantages with respect to the weight of fuel composition loaded on the container.

By the above method, the combustion of the fuel requires heat. DME vapor or spray is also fumigated into the air intake to provide an adequate means to ignite the fuel.

The amount of water in the exhaust gas may be calculated to be about 10% to 50%. Based on the initial water in the fuel and the water from the combustion of methanol and DME and the water in the intake air. This unexpectedly high result results from the high hydrogen content of methanol (which contains more hydrogen on a volume basis than low temperature liquid hydrogen), and the high content of water in the fuel, water vapor in the intake and water combustion products from the fuel (methanol and DME).

For this combustion reaction, excess water will be produced and there is a portion that is captured for recycling and mixing with the lower water content premix fuel stored in the storage vessel. In some embodiments, it is advantageous to reduce supply chain stream costs associated with the presence of water in the fuel by transporting higher methanol content based fuels, and meet the target engine quality for higher water content levels by capturing water from the engine exhaust.

The heat exchange and spray chamber arrangement using water that may have been purified with optional additives for selected species removed at the end of the period may be configured to ensure that non-CO 2 contamination from methanol combustion is close to zero. In addition, final cleaning of the exhaust gas can be achieved by adsorbing unburned methanol to an active surface for subsequent desorption and recycle to the engine in the process or for incorporation as part of a fumigant or main fuel using known techniques.

In the case of SOX, the exhaust gas may have the following analysis in this case:

SOX＜0.1ppm。

in general, emissions of other polluting agents (e.g. NOX particulates) will be much lower compared to oil-based diesel fuels.

Any small amounts of NOx and SOx formed during the combustion phase and CO in the aqueous phase₂May result in weak acidification of the water returned to mix with the fuel. The return water mixture may require chemical treatment or mechanical conditioning to counteract this weak acidification.

The exhaust resulting from such cleaning has improved emissions compared to diesel fuel in terms of hydrocarbon, particulate, NOX and SOX emissions, which is environmentally advantageous.

CO₂Recovering

The exhaust gas from high water fuel contains almost no impurities, making it ideal for subsequent processing. In particular, the CO may be converted to a CO using an energy source, which may include renewable resources, such as solar energy and the like₂Conversion back to methanol for direct reduction of greenhouse gas CO₂Or is highPurity of CO₂Can be used for organic growth such as algae for a variety of end uses, including methanol production.

By separating or purifying the oxygen level in the air, nitrogen may be reduced or purged from the engine, wherein the reduction or purging of the NOX potential is achieved through the oxidation of nitrogen. Exhaust CO₂The cycle being engine O₂The intake will optimize the oxygen level into the engine and produce mainly pure CO₂And steam venting. The CO is₂Is ideal for further processing into methanol or the above-mentioned applications, if desired.

Example 7: fuel consisting of 10% water 5% DME 85% methanol by weight, with fumigant

Fumigants such as 100% DME required at full load can be reduced to the range of 1% to 2%.

Example 8: fuel composition and fumigant combination

In the table below, examples of methanol/water fuel compositions and corresponding fumigant levels are given, which allow smooth operation of the compression ignition engine. The table has two parts, the main fuel of each numbered row being paired with a suitable fumigant of the same numbered row, but pairing between adjacent fuels and fumigants is also possible. Given the consistency of the fuel extender, lubricant, ignition improver, and other additives, they are selected from the examples provided in the detailed description above. The% amounts of these additives mentioned in the tables refer to the amount of the single additive described or the total amount of the additives described when more than one additive of this class is used in combination. Particular examples employ sugars or fatty acid esters as fuel extenders, fatty acid esters or ethanolamine derivatives as lubricity additives, ethers as ignition enhancers, and product colors and flame color additives as additional additives.

A number of fumigants are shown in the table, some of which have lower ignition characteristics than those classified as higher ignition components. The listed components are not exclusive and other suitable components listed elsewhere in the document and known to the person skilled in the art may also be used.

Δ wt%: with the exception of the 100% water/methanol combination

^＊Total fuel feed by weight.

Claims (42)

1. A method of powering a compression ignition engine using a main fuel comprising methanol and water, and comprising:

fumigating an incoming air stream with a fumigant comprising an ignition enhancer;

introducing the fumigated intake air into a combustion chamber of the engine and compressing the intake air;

introducing the main fuel into the combustion chamber, the main fuel comprising methanol and at least 12 wt% water and 0 wt% to 20 wt% dimethyl ether; and

igniting the main fuel/air mixture to drive the engine.

2. The method of claim 1, comprising fumigating the intake air with the fumigant in an amount of 0.5 to 70% by weight of main fuel.

3. The method of claim 1, comprising fumigating the intake air with the fumigant in an amount of up to 20 wt% of the main fuel.

4. The method of claim 1, comprising fumigating with a fumigant comprising ether as the ignition enhancer.

5. The method of claim 4, comprising fumigating with a fumigant comprising dimethyl ether.

6. The method of claim 1, comprising introducing a main fuel comprising water and methanol in a weight ratio of 12: 88 to 80: 20 into the combustion chamber.

7. The method of claim 1, comprising introducing a main fuel comprising methanol, 12 to 23 wt% water, and no more than 20 wt% additives.

8. The method of claim 1, comprising introducing a main fuel comprising 12 to 40 wt% water, methanol, and no more than 20 wt% additives.

9. The method of claim 1, comprising introducing a main fuel comprising 20 to 22 wt% water, methanol, and no more than 20 wt% additives.

10. The method of claim 9, comprising introducing a main fuel comprising 20 to 22 wt% water, 4 to 6 wt% dimethyl ether and methanol.

11. The method of claim 1, wherein the primary fuel comprises one or more additives selected from the group consisting of: ignition promoters, fuel extenders, combustion enhancers, lubricity additives, product coloring additives, flame color additives, anti-corrosion additives, biocides, pour point depressants, deposit reducers, denaturants, pH control agents, and mixtures thereof.

12. The method of claim 1, wherein the main fuel comprises crude methanol and up to 60 wt.% of non-aqueous additives, or the main fuel comprises refined methanol and up to 25 wt.% of non-aqueous additives.

13. The method of claim 1, comprising preheating the intake air in the combustion chamber prior to feeding the main fuel to the combustion chamber.

14. The method of claim 13, comprising preheating the incoming air to at least 130 ℃.

15. The method of claim 1, comprising producing the ignition enhancer by catalytic conversion of methanol in the main fuel composition stream.

16. The method of claim 1, comprising providing a pre-fuel comprising methanol and an ether as an ignition enhancer, separating the ignition enhancer from the pre-fuel, fumigating the incoming air stream with the ignition enhancer separated from the pre-fuel, and introducing a balance of the pre-fuel into the combustion chamber as the main fuel after separating the ignition enhancer.

17. A process for powering a compression ignition engine using a main fuel comprising water and methanol in a weight ratio of from 12: 88 to 60: 40, and comprising:

fumigating an incoming air stream with a fumigant comprising an ignition enhancer in an amount of 0.5 to 70% by weight of the main fuel;

introducing the fumigated intake air into a combustion chamber of the engine and compressing the intake air;

introducing the main fuel into the combustion chamber, the main fuel comprising methanol and at least 12 wt% water and 0 wt% to 20 wt% dimethyl ether; and

igniting the main fuel/air mixture to drive the engine.

18. The method of claim 17, wherein the ignition enhancer comprises dimethyl ether.

19. A compression ignition engine fuel for use in a compression ignition engine, the fuel being fumigated with a fumigant comprising an ignition enhancer into an air inlet of the engine, the fuel comprising methanol and at least 12 wt% water, and one or more additives selected from: ignition improver, fuel extender, combustion enhancer, lubricity additive, product coloring additive, flame color additive, anti-corrosion additive, biocide, pour point depressant, deposit reducing agent, denaturant, pH control agent, and mixtures thereof, wherein the fuel comprises from 0 wt% to 20 wt% dimethyl ether.

20. The fuel of claim 19, wherein the fuel comprises from 12 wt% to 40 wt% water and from 0 wt% to 20 wt% dimethyl ether.

21. The fuel of claim 19 or 20, wherein the additive comprises of the fuel:

-up to 1% by weight of a product coloring additive, and

-up to 1 wt% of a flame colour additive.

22. Use of a fuel comprising methanol and at least 12 wt% water and 0 wt% to 20 wt% dimethyl ether in a compression ignition engine with fumigation of an air inlet into the compression ignition engine with an ignition enhancer.

23. A two-part fuel for use in operating a compression ignition engine by fumigation of an ignition enhancer into an air inlet of the engine, the fuel composition comprising:

-a main fuel composition comprising methanol and at least 12 wt% water and 0 to 20 wt% dimethyl ether, and

-a secondary fuel component comprising an ignition enhancer.

24. Use of a two part fuel as claimed in claim 23 in a compression ignition engine, wherein the primary fuel is introduced into a combustion chamber of the compression ignition engine and the secondary fuel is fumigated into an air inlet of the compression ignition engine.

25. A method of supplying fuel to a compression ignition engine, the method comprising:

-supplying a main fuel composition comprising methanol and at least 12 wt% water and 0 wt% to 20 wt% dimethyl ether to a first vessel in fluid connection with a combustion chamber of the compression ignition engine, and

-supplying a secondary fuel component comprising an ignition enhancer to a second vessel fluidly connected to an air intake of the compression ignition engine.

26. A power generation system, comprising:

generating power using a methanol-water fuel to power a compression ignition engine, wherein the methanol-water fuel comprises methanol and at least 12 wt% water and 0 wt% to 20 wt% dimethyl ether;

preheating an incoming air stream of the compression ignition engine and/or fumigating the incoming air stream with an ignition enhancer;

treating engine exhaust gas to recover heat and/or water exhausted from the engine, an

The heat and/or water is redirected for other uses.

27. The power generation system claimed in claim 26, comprising recycling the rejected heat and/or water back into the engine.

28. The power generation system claimed in claim 26, comprising exchanging heat from the exhaust gas through a heat exchanger to water in a hot water circuit and transferring heat in the water through the hot water circuit to a local community.

29. The power generation system claimed in claim 26, wherein the system is adapted to power a rail vehicle, which includes treating exhaust gas to remove particulates from the exhaust gas and recovering heat and water for recirculation back into the engine and/or for the rail vehicle.

30. The power generation system of claim 26 wherein the power generation system is adapted to power a marine vehicle comprising processing exhaust gas in a desalter to recover heat and water for recirculation back into the engine and/or redirection for the marine vehicle.

31. The power generation system claimed in claim 26, comprising mixing engine exhaust with water in a mixer to cool the exhaust and recover water from exhaust condensate.

32. The power generation system claimed in claim 31, comprising pumping water containing exhaust gas from the mixer to a liquid/gas heat exchanger to further cool an exhaust gas/water mixture and recover rejected heat and/or water.

33. The power generation system claimed in claim 26, comprising recovering water from the exhaust in the final stage exhaust condenser.

34. The power generation system claimed in claim 26, comprising adding a chemical treatment to the exhaust gas to neutralize any pH or other imbalance.

35. The power generation system claimed in claim 26, comprising treating a pre-fuel composition comprising methanol and ether, and optionally water, in a pre-treater, wherein the pre-treater separates the ether from the methanol and uses the ether as an ignition enhancer when fumigating an incoming air stream.

36. The power generation system claimed in claim 35, wherein the pre-fuel composition includes 7 wt% to 10 wt% ether.

37. The power generation system claimed in claim 26, comprising preheating the incoming air to 150 ℃ to 300 ℃.

38. The power generation system claimed in claim 26, comprising adding water to the methanol-based fuel to power the engine using a methanol-water fuel.

39. The power generation system claimed in claim 26, comprising transporting the fuel from a fuel production plant to the engine.

40. The power generation system claimed in claim 35, comprising transporting the pre-fuel composition from a fuel production plant to the engine.

41. A method of delivering a pre-fuel composition comprising methanol and ether, comprising delivering the pre-fuel from a first location to a second location remote from the first location, and separating the ether from the methanol to produce a first fuel portion comprising methanol and 0 wt% to 20 wt% ether and a second fuel portion comprising ether.

42. The method of claim 41, wherein the ether is dimethyl ether.