HK1097566B - Treatment of crude oil fractions, fossil fuels, and products thereof - Google Patents

Description

Treatment of crude oil fractions, fossil fuels and products thereof

Technical Field

The present invention relates to the field of chemical processes for treating crude oil fractions and various types of products derived and obtained therefrom. In particular, the present invention relates to reforming processes and double bond saturation as ring opening reactions to improve the quality of fossil fuels and to convert organic products into forms with improved performance and broader utility. The present invention also relates to the removal of sulfur-containing compounds, nitrogen-containing compounds, and other undesirable components from petroleum and petroleum-based fuels.

Background

Fossil fuels are the largest and most widely used energy source in the world, having high efficiency, high performance, and relatively low price. Fossil fuels are of many different types, including petroleum fractions, coal, tar sands, and shale oil, and their uses include consumer self-use, such as automotive engines and home heating, and commercial applications, such as boilers, furnaces, smelting units, and power plants.

Fossil fuels and other crude oil fractions and products derived from natural resources contain a large number of hydrocarbons that vary widely in molecular weight, boiling and melting points, reactivity, and ease of handling. Many industrial processes have been developed to improve these materials by removing, diluting or otherwise converting heavier components or components that are prone to polymerization or solidification, particularly olefins, aromatics and fused ring compounds such as naphthalene, indane and indene, anthracene, phenanthrene. A common method of converting these compounds is to achieve saturation by double bond hydrogenation.

The removal of sulfides is of increasing interest, particularly for fossil fuels. Sulfur in the sulfides causes corrosion of pipelines, pumps and refining equipment, poisons catalysts used in refining and burning fossil fuels, and can also prematurely destroy combustion engines. Sulfur for controlling nitrogen oxides NO in diesel-powered locomotives and buses_xThe exhausted catalytic converter is poisoned. Sulfur also results in increased particulate (soot) emissions from trucks and buses by reducing the effect of the soot trap. The combustion of sulfur-containing fuels produces sulfur dioxide, which enters the atmosphere as acid rain, can damage crops and wildlife, and is harmful to human health.

The clean air act and its amendments in 1964 set sulfur emission standards that were difficult to achieve and expensive to achieve. According to this act, the U.S. environmental protection agency establishes an upper limit for the sulfur content of diesel fuel of 15ppmw, which will be effective in 2006. This criterion is significantly reduced compared to 500ppmw as specified in the 2000 effective. For the reconstituted gasoline, the standard 300ppmw in 2000 has dropped to 30ppmw effective at 1 month 1 in 2004. In 2005, the european union enacted a similar change, namely a mandatory limit to 50ppmw for the sulfur content of gasoline and diesel fuels. The treatment of fuels to reduce sulfur emissions sufficiently low to meet these requirements is difficult and expensive, and the resulting increase in fuel prices will have a significant impact on the world's economy.

In the prior art, the main method of fossil fuel desulfurization is hydrodesulfurization, i.e., the reaction between fossil fuel and hydrogen gas at high temperature and pressure in the presence of a catalyst. This reduces the organic sulfur to gas H₂S, and the H₂S is then oxidized to elemental sulfur according to the Claus process. But still a considerable amount of unreacted H₂S, which can present a health hazard. A further limitation of hydrodesulfurization is that it is not as effective for removing all sulfur-containing compounds. Such as mercaptans, thioethers and disulfides, are easily decomposed and removed by certain processes, whereas aromatic sulfur compounds, cyclic sulfur compounds and condensed polycyclic sulfur compounds do not readily react to such processes. Thiophenes, benzothiophenes, dibenzothiophenes, other fused ring thiophenes, and substituted products of these compounds are difficult to hydrodesulfurize, but these compounds account for as much as 40% of the total sulfur content of middle east crude oil and 70% of the total sulfur content of west texas crude oil.

Due to the drawbacks of the hydrodesulphurization process, some new processes have emerged, the most prominent of which is oxidative desulphuration, which aims at high desulfurization efficiency. Essentially, the process generally involves oxidizing sulfur, if present, using an oxidizing agent, such as a hydroperoxide or peracid, thereby converting the sulfur compound to a sulfone. To promote this oxidation reaction, ultrasound may be applied, as taught in U.S. Pat. No. US 6402939 to Yen et al entitled "oxidative desulfurization of fossil fuels using ultrasound"; also U.S. Pat. No. 6500219 to Gunnerman, entitled "continuous Process for the oxidative desulfurization of fossil fuels and products thereof utilizing ultrasound" the teachings of which are expressly incorporated herein by reference.

Advantageously, oxidative desulfurization can be carried out at mild temperatures and pressures, and generally does not require hydrogen. More advantageously, oxidative desulfurization requires much less capital cost. In this regard, oxidative desulfurization can be selectively used to treat individual fractions of refined petroleum, such as diesel, and is readily integrated into existing refinery facilities as a refining process. Perhaps most advantageously, the oxidative desulfurization can remove substantially all of the sulfur species present in a defined amount of crude oil, thereby allowing for ultra-low sulfur levels, particularly to meet the lower sulfur standards set by various regulations.

Despite these advantages, oxidative desulfurization is not currently effectively used in large scale refinery operations because the currently employed oxidative desulfurization techniques only partially oxidize the sulfur species present to sulfoxides, rather than sulfones. In this regard, existing oxidative desulfurization techniques are too limited to achieve the necessary extensive oxidation necessary for large scale implementation. In addition, sulfur is only partially oxidized (i.e., to sulfoxide), and the final removal of sulfur species is usually accomplished by solvent extraction or absorption, which is based on the difference in polarity of the sulfones, assuming the sulfones are present, and thus, these processes are not conducive to removal of sulfoxides based on their lower polarity degree (as compared to sulfones). Therefore, substantial improvements must be made before the oxidative desulfurization technique can be practically implemented.

In addition to sulfur-containing compounds, nitrogen-containing compounds should also be removed from fossil fuels because these compounds poison the acidic components of hydrocracking catalysts used in refineries. The nitrogen-containing compounds are removed by hydrodenitrogenation, a process that is a hydrotreating process carried out in the presence of a metal sulfide catalyst. Both hydrodesulfurization and hydrodenitrogenation require expensive catalysts and high temperatures (typically 400-Equal to 204-. These processes also require a hydrogen source or an on-site hydrogen production facility, which in turn entails high capital and operating costs. In both processes there is also a risk of hydrogen leaking from the reactor.

Thus, there is a clear need in the art for a system and process that can effectively operate to remove sulfur from refined fossil fuels, that can substantially effectively remove substantially all of the sulfur species present in the fossil fuels, that is extremely cost effective, and that is easily integrated into conventional refinery processes. Also, there is a need in the art for a process for efficiently removing nitrogen-containing compounds that is also cost effective and can substantially efficiently remove substantially all of the nitrogen species present in the fossil fuel. In addition, there is still a need for such a process that can improve the quality of the refined fossil fuels processed and can be used in large or small scale refining operations.

Disclosure of Invention

It has now been found that fossil fuels, crude oil fractions and components derived from these sources can undergo advantageous conversions and be upgraded in various ways by a process that applies heat and an oxidizing agent to the feedstock in a reaction medium, and preferably with sonic energy. The fossil fuel crude oil fraction is preferably combined with water to form an emulsion to facilitate the reaction to achieve the desired fossil fuel purification and quality improvement. Hydrogen is not required but can be utilized as part of a conventional hydrotreating process to facilitate the removal of contaminants, particularly sulfur and nitrogen. In some embodiments of the invention, the treatment is carried out with sonic energy in the presence of a hydroperoxide. In other embodiments, a transition metal catalyst is used. One surprising discovery associated with some embodiments of the present invention is that in some applications, the conversion achieved using the present invention can be achieved without the inclusion of hydroperoxides in the reaction mixture.

Among the conversions achieved by the present invention are the removal of organic sulfur compounds, the removal of organic nitrogen compounds, the saturation of double bonds and aromatic rings, and the opening of fused ring structures. The invention also relates to processes for converting arenes to cycloalkanes and opening one or more rings of fused cyclic structures, such as converting naphthalene to monocyclic arenes, converting anthracene to naphthalene, converting fused heterocycles such as benzothiophenes, dibenzothiophenes, benzofurans, quinolines, indoles, and the like to substituted benzenes, converting acenaphthylene (acenaphthalene) and acenaphthylene to indanes and indenes, and converting monocyclic arenes to acyclic structures. In addition, the present invention relates to a process for converting alkenes to alkanes and to a process for opening carbon-carbon, carbon-sulfur, carbon-metal and carbon-nitrogen bonds.

In addition to the foregoing, API gravity of fossil fuels and crude oil fractions increases (i.e., density decreases) as a result of processing according to the present invention. Thus, fossil fuels and fractions thereof treated in accordance with the present invention can be readily separated into layers by conventional centrifugation processes to produce a light, low sulfur layer and separated from a heavier, high sulfur layer. In this respect, since the process of the present invention facilitates the oxidation of sulfur compared to other compounds, these oxidized sulfides, i.e., sulfones, are precipitated and thus remain in the separated heavier crude oil layer. Alternatively, if the sulfur compounds are not oxidized and/or an oxidizing agent is not used in the process of the present invention, the sulfur may not be retained in the heavier crude layer even under centrifugal force, particularly when these fractions are allowed to produce a heavy bitumen resin layer.

In addition, the present invention increases the cetane index of petroleum fractions and cracked products having boiling points or ranges in the diesel range. The term "diesel range" is used herein in an industrial sense to mean generally at about 200 ℃ (392 mm) after naphtha) To 370 ℃ (698)) A fraction of crude oil distilled off in the temperature range of (a). Also included are fractions and cracked products having a boiling range within this range and fractions having a boiling range largely overlapping this range. Examples of refinery fractions and streams in the diesel range are Fluid Catalytic Cracking (FCC) cycle oil fractions, coker distillate fractions, straight run diesel fractions and blends. The present invention also imparts other beneficial changes such as lowering the boiling point and removing components that are detrimental to fuel performance and affect refinery processes, as well as increasing the cost of fuel production. For example, FCC cycle oils can be treated in accordance with the present invention to significantly reduce their aromatic content.

Other crude oil fractions of particular utility in the present invention are gas oils, which term is used herein in phase with its meaning in the petroleum industryAnd, as used herein, refers to liquid petroleum distillates having a higher boiling point than naphtha. The initial boiling point can be as low as 400(200 ℃ C.), but the preferred boiling point range is about 500 ℃ 1100(about 260 ℃ C. -. 595 ℃ C.). Examples of fractions boiling in this range are FCC slurry oil, light and heavy gas oil (the term is applied because of their different boiling points) and coker gas oil. All terms used herein and before are used with their meaning in the petroleum art.

The conversion by the process of the present invention causes the hydrocarbon stream to undergo changes in its cold flow characteristics, including pour point, cloud point and freeze point. The invention also reduces sulfur compounds, nitrogen compounds and metal-containing compounds, and the application of the process of the invention significantly reduces the burden on conventional processes such as hydrodesulfurization, hydrodenitrogenation and hydrodemetallization, so that these processes can be carried out more efficiently and effectively.

These and other advantages, features, applications and embodiments of the present invention will become apparent from the following description.

Detailed Description

The term "liquid fossil fuel" as used herein refers to carbonaceous liquids derived from petroleum, coal, or any other natural feedstock, as well as processed fuels such as gas oils and products of fluid catalytic crackers, hydrocrackers, thermal crackers, and cokers, which are used to produce energy for a variety of purposes, including industrial, commercial, municipal, and consumer uses. These fuels include automotive fuels such as gasoline, diesel fuel, jet fuel, and rocket fuel, as well as petroleum residual based fuel oils, including bunker fuels and residual fuels. For example, No.6 fuel oil, which is also known as "bunker C" fuel oil, is used in oil-fired power plants as the primary fuel, and also in the shipbuilding industry as the primary propulsion fuel for ships. No.4 fuel oil and No.5 fuel oil are used for heating large buildings, such as schools, apartment buildings, office buildings, and large stationary marine engines. The heaviest fuel oils are vacuum residuum from fractional distillation, commonly referred to as "vacuum residuum," with a boiling point of 565 ℃ or higher, which is used as bitumen and coker feedstock. The invention can be used to treat any of these fuels and fuel oils to reduce the sulfur, nitrogen and aromatics content thereof and to improve performance and extend utility. Some embodiments of the invention include processing diesel range fractions or products including, but not limited to, straight-run diesel fuel, raw shelf diesel fuel (commercially available to consumers at gas stations), light cycle oil, and mixtures of straight-run diesel and light cycle oil in a ratio range of about 10: 90 to 90: 10 (straight-run diesel: light cycle oil).

The term "crude oil fraction" as used herein refers to various refinery products produced from crude oil by atmospheric distillation or vacuum distillation, including fractions that have been hydrocracked, catalytically cracked, thermally cracked, or coked, and fractions that have been desulfurized. Examples are light virgin naphtha, heavy virgin naphtha, light steam cracked naphtha, light thermally cracked naphtha, light catalytically cracked naphtha, heavy thermally cracked naphtha, reformed naphtha, alkylated naphtha, kerosene, hydrogenated kerosene, gasoline and light virgin gasoline, virgin diesel, atmospheric gas oil, light vacuum gas oil, heavy vacuum gas oil, residual oil, vacuum residual oil, light coker gasoline, coker distillate, FCC (fluid catalytic cracker) cycle oil, and FCC slurry oil.

The term "fused ring aromatic compound" as used herein refers to a compound comprising two or more fused rings wherein at least one fused ring is a benzene ring with or without substituents, and includes compounds wherein all fused rings are benzene rings or hydrocarbon rings, and compounds wherein one or more fused rings are heterocyclic rings. Examples include substituted and unsubstituted naphthalene, anthracene, benzothiophene, dibenzothiophene, benzofuran, quinoline, and indole.

The term "olefin" as used herein means a hydrocarbon, primarily a compound containing two or more carbon atoms and one or more double bonds.

Fossil fuels and crude oil fractions treated by the present invention have significantly improved properties relative to the same feedstock prior to treatment, these improvements make the products unique and improve their use as fuels. Specifically, the present invention makes the condensed ring aromatic compound open efficiently by converting it into a saturated compound. The process can likewise convert olefins to saturated compounds, so that at least one or more of the double bonds present are replaced by single bonds.

Another characteristic that is improved by the present invention is API gravity. The term "API gravity" as used herein is well known to those skilled in the art of petroleum and petroleum-derived fuels. In summary, the term is used by the American Petroleum institute as a measurement scale on which the value increases as the value of specific gravity decreases. Thus, a relatively high API gravity indicates a relatively low density. API weight values ranged from-20.0 (equivalent to a specific gravity of 1.2691) to 100.0 (equivalent to a specific gravity of 0.6112).

The process of the present invention can be used with any liquid fossil fuel, preferably a liquid fossil fuel having an API gravity in the range of-10 to 50, and more preferably in the range of 0 to 45. For feedstocks boiling in the diesel range, the process of the invention is preferably carried out in such a way that the feedstock is converted into a product having an API gravity of from 37.5 to 45. The FCC cycle oil is preferably converted to products having an API gravity of 30-50. For liquid fossil fuels in general, it is preferred to practice the process of the present invention to increase the API gravity by 2 to 30 API gravity units, more preferably by 7 to 25 units. That is, the present invention preferably increases the API gravity from below 20 to above 35.

As previously mentioned, fossil feedstocks boiling in the diesel range that are treated in accordance with the present invention experience an increase in the cetane index (also referred to in the art as the "cetane number") after treatment in accordance with the present invention. Diesel fuels of particular interest to the present invention in this regard are fuels having a cetane index in excess of 40, preferably in the range of 45 to 75, most preferably in the range of 50 to 65. The increase in cetane index can also be expressed as an increase in the index relative to the feedstock prior to treatment by the process of the present invention. In some preferred embodiments, the increase is in the range of 1 to 40 cetane index units, more preferably 4 to 20 units. The expression further means that the present invention preferably increases the cetane index from below 47 to about 50. The invention can be used to produce diesel fuel having a cetane index greater than 50.0 or preferably greater than 60.0. From a range point of view, the present invention is capable of producing diesel fuel having a cetane index of from about 50.0 to 80.0, and preferably from about 60.0 to 70.0. The cetane index or value is to be understood as meaning the same in the present description and in the appended claims to those skilled in the art of automotive fuels.

As noted above, in some embodiments of the invention a hydroxide is included in the reaction mixture. The term "hydroperoxide" is used herein to refer to a compound having the following molecular structure: R-O-O-H, wherein R represents a hydrogen atom or an organic or inorganic group. The hydroperoxide in which R is an organic group is a water-soluble hydroperoxide such as methyl hydroperoxide, ethyl hydroperoxide, isopropyl hydroperoxide, n-butyl hydroperoxide, sec-butyl hydroperoxide, tert-butyl hydroperoxide, 2-methoxy-2-propyl hydroperoxide, tert-amyl hydroperoxide and cyclohexyl hydroperoxide. Examples of hydroperoxides in which R is an inorganic group are peroxynitrous acid, peroxyphosphoric acid and peroxysulfuric acid. Preferred hydroperoxides are hydrogen peroxide (where R is a hydrogen atom) and tertiary alkyl peroxides, especially tertiary butyl peroxide.

The aqueous fluid that may optionally be combined with fossil fuels or other liquid organic feedstocks in the process of the present invention may be water or any aqueous solution. The relative amounts of organic and aqueous phases may vary and, although it may affect the efficiency of the process and the ease of handling the fluids, the relative amounts are not critical to the present invention. In this regard, it is believed that the amount of aqueous fluid may be from 0 to 99 wt% of the combined organic and aqueous phases. In most cases, however, best results will be achieved when the volume ratio of the organic phase to the aqueous phase is from about 8: 1 to about 1: 5, preferably from about 5: 1 to about 1: 1, and most preferably from about 4: 1 to about 2: 1.

Although optional, when hydroperoxide is present, the amount of hydroperoxide relative to the organic and aqueous phases can vary, and although conversion and yield may vary somewhat with the proportion of hydroperoxide, the actual proportion is not critical to the invention and any excess will be eliminated by the application of sonic energy. For example, H is calculated as one component of the combined organic and aqueous phases₂O₂In the amount of (2), for most of H₂O₂Is present in an amount of about 0.0003 to 70% by volume (as H) of the combined phases₂O₂In terms of volume), preferably about 1.0 to 20 volume percent, will generally yield favorable results. For removing H₂O₂Other hydroperoxides than these are preferably present in concentrations of comparable amounts.

In some embodiments of the invention, surfactants or other emulsion stabilizers are added to stabilize the emulsion. Some petroleum fractions contain surfactants as the natural components of the fraction, and these agents themselves stabilize the emulsion. In other cases, synthetic or non-natural surfactants may also be added. Any of a variety of materials known to be effective as emulsion stabilizers may also be used. A list of these materials is available in the first roll of McCutcheon: emulsifiers and detergents-1999 North American edition, USA, New Jersey, Glen Rock, McCutcheon division, MC publishing Co., and other published literature. Cationic, anionic and nonionic surfactants can be used. Preferred cationic surfactants are quaternary ammonium salts, quaternary phosphonium saltsSalts and crown ethers. Examples of quaternary ammonium salts are tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, tetrabutylmethylammonium chloride, phenyltrimethylammonium chloride, phenyltriethylammonium chloride, methyltrioctylammonium chloride, dodecyltrimethylammonium bromide, tetraoctylammonium bromide, hexadecyltrimethylammonium chloride and trimethyldecammonium chlorideAn octaalkyl ammonium hydroxide. Quaternary ammonium halides can be used in a variety of systems, with dodecyl trimethyl ammonium bromide and tetraoctyl ammonium bromide being most preferred.

Preferred surfactants are those which promote the formation of an emulsion between the organic and aqueous phases when the fluid is passed through a common mixing pump, but which will spontaneously separate the product mixture into aqueous and organic phases suitable for immediate separation by decantation or other simple phase separation process. One class of surfactants that can accomplish this is aliphatic C₁₅-C₂₀Preferably, the specific gravity of the hydrocarbon(s) and mixtures of such hydrocarbons is at least about 0.82, most preferably at least about 0.85. Examples of hydrocarbon mixtures which meet the above requirements, are particularly suitable for use and are readily available, are mineral oils, preferably heavy or extra heavy mineral oils. The terms "mineral oil", "heavy mineral oil" and "extra heavy mineral oil" are well known in the art and are used herein in the same sense as they are commonly used in the art. Such oils are readily available from industrial chemical suppliers worldwide.

In the practice of the present invention, when an added emulsifier is used, a suitable amount of the agent is any amount that will function as described above. In addition, the amount is not critical and may vary with the choice of agent, and in the case of mineral oil, with the grade of mineral oil. The amount may also vary with the fuel composition, the relative amounts of the aqueous and organic phases, and the operating conditions. Appropriate choices are, for the skilled engineer, only routine choices and adjustments. In the case of mineral oil, the best and most effective results are generally obtained using a volume ratio of mineral oil to organic phase of from about 0.00003 to about 0.003.

In some embodiments of the invention, a metal catalyst may be included in the reaction system to adjust the activity of the hydroxyl groups generated by the hydroperoxide. Examples of such catalysts are transition metal catalysts, preferably metals having atomic numbers 21 to 29, 39 to 47 and 57 to 79. Particularly preferred metals are nickel, sulfur, tungsten (and tungstates), cobalt, molybdenum, and combinations thereof. In some systems within the scope of the present invention, Fenton catalysts (ferrous salts) and metal ion catalysts are generally useful as iron (II), iron (III), copper (I), copper (II), chromium (III), chromium (VI), molybdenum, tungsten, cobalt, and vanadium ions. Among them, iron (II), iron (III), copper (II) and tungsten catalysts are preferable. For some systems, such as crude oil systems, Fenton's catalyst is preferred, while for other systems, such as diesel-containing systems, tungsten or tungstate is preferred. Tungstates include tungstic acid, substituted tungstic acids such as phosphotungstic acid and metal tungstates. In some embodiments of the invention, nickel, silver or tungsten or a combination of these three metals is particularly useful. When present, the metal catalyst will be used in a catalytically effective amount, meaning that any amount that promotes the reaction toward the desired target, particularly oxidation of sulfide to sulfone (i.e., increases the rate of reaction) can be used. The catalyst may be retained in the acoustic energy transmission chamber in the form of metal particles, pellets, flakes, fines or other similar forms by a physical barrier, such as a wire mesh or other restraining means, through which the reaction medium is allowed to pass.

Among the above catalysts, phosphotungstic acid is more preferably included, or a mixture of sodium tungstate and phenylphosphonic acid may be used because they are less expensive and available in large quantities. It is to be understood, however, that the use of these catalysts is optional but is required for the practice of the invention by those skilled in the art.

The temperature of the aqueous and organic phases of the mixture may vary over a wide range, although it is believed that in most cases the temperature may be raised to about 500 ℃, preferably about 200 ℃, and most preferably not more than 125 ℃. If the temperature is not high enough to volatilize the organic liquid, the optimum degree of heating will vary depending on the particular organic liquid being treated and the ratio of aqueous phase to organic phase. For diesel fuel, for example, best results are generally obtained by preheating the fuel to at least about 70 c, preferably about 70-100 c. The aqueous phase may be heated to any temperature up to its boiling point.

Although optional, the sonic energy used in the present invention has a sonic frequency in the range of about 2 to 100kHz, with a preferred range of about 10 to 19 kHz. In a more preferred embodiment, the sonic energy utilized has a frequency in the range of about 17 to 19 kHz.

As will be appreciated by those skilled in the art, these acoustic waves may be obtained from mechanical, electrical, electromagnetic, or other known energy sources. In this regard, various methods of generating and applying sonic energy and suppliers of sonic energy generating equipment are known to those skilled in the art. Such systems that can be used to practice the invention to the extent necessary to achieve the sonic energy disclosed herein include ultrasonic systems produced by the Hielscher system of Teltow, germany and distributed domestically by Hielscher USA, inc.

The intensity of the sonic energy applied is preferably of sufficient magnitude to facilitate oxidation of at least a portion of the sulfur-and nitrogen-containing species present in the fossil fuel being treated while simultaneously opening the fused ring compounds and saturating the olefin compounds that may be present. It is now believed that the amplitude of the applied sonic energy ranges from about 10 to 300 microns and can be adjusted depending on whether the process of the present invention is carried out at elevated temperatures and/or pressures. To the extent that the process of the present invention is carried out at room temperature and pressure, suitable amplitudes may range from about 30 to 120 microns, preferably from about 36 to 60 microns. The power (i.e., power density) that should be delivered per unit volume should preferably be about 0.01 to 100.00 watts per cubic centimeter of liquid to be treated, preferably about 1 to 20 watts per cubic centimeter of liquid to be treated. It should be understood that the higher power densities that may be achieved, provided that existing equipment can produce output powers as high as 16 kilowatts, the higher power outputs may be obtained to facilitate the reactions of the present invention.

The time of exposure of the reaction medium to the acoustic energy is not critical to the practice of the invention or the success of the invention, and the optimum exposure time will vary with the type of fuel being treated. An advantage of the present invention is that effective and useful results can be achieved with relatively short exposure times. Preferred exposure times range from about 1 second to about 30 minutes, more preferably from about 1 second to 1 minute, with excellent results being obtained with exposure times of about 5 seconds and possibly less.

The efficiency and effectiveness of the process can also be increased to a desired degree by recycling or using sonic energy for secondary treatment. For example, fresh water may be added to the treated and separated organic phase to form a fresh emulsion, which is then further treated by continuous or intermittent exposure to sonic energy. The exposure to sonic energy may be repeated multiple times for better results, and better results may be readily achieved in a continuous process using a recycle stream or using a second stage sonic energy treatment and possibly a third stage sonic energy treatment, with fresh water feed added at each stage.

In systems where the reaction induced by the application of sonic energy produces undesirable by-products in the organic phase, these by-products can be removed by extraction, absorption or filtration. For example, when the by-product is a polar compound, the extraction process may be any process that extracts a polar compound from a non-polar liquid medium. Such processes include solid-liquid extraction using absorbents such as silica gel, activated alumina, polymeric resins, and zeolites. Liquid-liquid extraction can also be applied using polar solvents such as dimethylformamide, N-methylpyrrolidone or acetonitrile. A variety of organic solvents that are immiscible or immiscible with fossil fuels, such as toluene and the like, may be used.

Alternatively, any by-products produced in the organic phase which consist of oxidized nitrogen and sulfur containing species such as sulfoxides and sulfones may be treated in a conventional hydrodesulfurization process. In this regard, the oxidation process of the present invention may be incorporated into the processes disclosed in the following patents: pending U.S. patent application No.10/411,796, filed on day 4/11/2003, entitled "sulfone removal process", and U.S. patent application No.10/429,369, filed on day 5/2003, entitled "process for producing and removing sulfoxides from fossil fuels", the teachings of which are incorporated herein by reference.

To facilitate the removal of sulfur-containing compounds, the process of the invention may be further combined with the use of a centrifugation process, which centrifugation processThe fossil fuels treated according to the invention are advantageously classified or stratified in different densities. Specifically, after the ultrasonic and oxidizer treatments are applied to fossil fuels that may contain sulfur as described above, the resulting fossil fuels may then be subjected to a centrifugation step that will produce a light layer with a low sulfur content (i.e., low density) and a heavy layer with a higher sulfur content (i.e., more dense). In this regard, any sulfur-containing compounds present in fossil fuels are oxidized to sulfones, which will precipitate in the heavy layer. Alternatively, if no oxidizing agent is used and/or the sulfur is not oxidized, it is believed that the sulfur will still not precipitate into the denser, heavier layer, particularly when the crude oil fraction is centrifuged, as this centrifugation will produce a heavy pitch resin layer. In this respect, it is believed that the application of centrifugal force is effective not only to facilitate stratification, but also to potentially chemically break down any resin present, thus enabling separation, and potentially reducing the amount of bitumen present in the fossil fuel. Table 1 below shows the results of a crude oil fraction treated by centrifugation, in particular the results of the various components thereof, said fraction having been previously treated in the presence of 2.5% hydrogen peroxide at 60%Next, the mixture was treated with ultrasonic waves at about 19kHz for about 8 minutes. By applying the oxidation process and the centrifugation process, a light layer is produced, which is extracted and compared with a previously centrifuged composition.

TABLE 1

	Before one	Then (in the light layer)
			Sulfur	2.5	0.7

Alkane(s)	52	62
			Aromatic hydrocarbons	30	25
Asphalt	9	5
			100Lower viscosity cs	52	2

The reaction of the process of the present invention may generate heat, and in order to control the reaction, it may be preferred to remove some of the generated heat using some of the feedstock. For example, when treating gasoline in accordance with the present invention, it is preferred to cool the reaction medium when the treatment is carried out using sonic energy. Cooling may be performed using conventional methods, such as using a liquid coolant jacket or circulating a coolant through cooling coils inside the chamber using sonic energy. For these purposes, atmospheric water is an effective coolant. Suitable cooling methods or apparatus will be apparent to those skilled in the art. When dealing with diesel fuel, gas oil and residual oil, cooling is generally not necessary.

The operating conditions generally will vary significantly depending on the organic feedstock being treated and the manner of treatment for practicing the present invention. For example, the pH of the emulsion may be as low as 1 and as high as 10, but it is believed that the best results are achieved in the pH range of 2-7. The pressure of the emulsion may similarly vary when treated with sonic energy, ranging from subatmospheric (as low as 5psia or 0.34 atmospheres) to as high as 3,000psia (214 atmospheres), although preferably less than about 400psia (27 atmospheres), more preferably less than about 50psia (3.4 atmospheres), and most preferably from about atmospheric to about 50 psia.

The operating conditions described in the preceding paragraphs directed to the application of sonic energy, including emulsion stabilizers and catalysts and the usual conditions of temperature and pressure, are used in the present invention regardless of the presence of hydrogen peroxide or any other hydroperoxide in the reaction mixture. A unique and surprising discovery of the present invention is that the levels of sulfur-containing compounds and nitrogen-containing compounds are significantly reduced when sonic energy is applied in the foregoing process, regardless of the presence of hydroperoxides. Additionally, the processes disclosed herein can be carried out in a batch mode or a continuous flow mode of operation. It has also been surprisingly found that the various objects of the present invention (e.g., removal of sulfur and nitrogen, and improvement in fuel performance) can be readily achieved in a very cost effective and efficient manner, even when practicing the present invention without the use of sonic energy, but using only heat, a combination of heat and an oxidizing agent, and/or further using centrifugation and/or hydrodesulfurization.

Other adaptations and modifications of the invention will be apparent to those skilled in the art. Accordingly, the particular combination of parts and steps described herein is illustrative of only some embodiments of the invention and is not intended to limit alternative apparatus and methods within the spirit and scope of the invention.

Claims (14)

1. A method of treating a crude oil fraction to reduce the level of sulfur-containing compounds and nitrogen-containing compounds therein, said method comprising the steps of:

(a) mixing a hydroperoxide with the crude oil fraction to form a first mixture, and heating the mixture, the mixture being heated sufficiently to oxidize a majority of sulfur-containing compounds and a majority of nitrogen-containing compounds present in the crude oil fraction in the absence of an aqueous fluid, and exposing the mixture to sonic energy having a frequency in the range of 2 to 100kHz and an amplitude in the range of 10 to 300 microns; and

(b) separating the oxidized sulfur-containing compounds and oxidized nitrogen-containing compounds produced in step (a) from the crude oil fraction by hydrodesulfurization.

2. The method of claim 1 wherein said sonic energy has a frequency in the range of 2 to 19 kHz.

3. The method of claim 1 or 2, wherein the crude oil fraction is a fraction boiling in the diesel range.

4. The process of claim 3, wherein the crude oil fraction is selected from the group consisting of Fluid Catalytic Cracking (FCC) cycle oil fractions, coker distillate fractions, straight run diesel fractions, and mixtures thereof.

5. The method of claim 1 or 2, wherein the crude oil fraction is a fraction boiling in the gas oil range.

6. The process of claim 5 wherein the crude oil fraction is selected from the group consisting of FCC cycle oil, FCC slurry oil, light gas oil, heavy gas oil, and coker gas oil.

7. The method of claim 1 or 2 wherein the sonic energy is applied at a power density in the range of 0.01 to 100.00 watts per cubic centimeter of liquid to be treated.

8. The method of claim 7 wherein the sonic energy is applied at a power density in the range of 1 to 20 watts per cubic centimeter of liquid to be treated.

9. The method of claim 1 or 2 wherein the crude oil fraction is exposed to the sonic energy in step (a) for 1 second to 1 minute.

10. The process of claim 1 or 2, wherein the mixture is heated in step (a) to a temperature of no greater than 200 ℃.

11. The process of claim 10, wherein the mixture is heated in step (a) to a temperature of no greater than 125 ℃.

12. The process of claim 1 or 2, wherein step (a) is carried out at a pressure of less than 400 psia.

13. The process of claim 12, wherein step (a) is carried out at a pressure of less than 50 psia.

14. The process of claim 13, wherein step (a) is carried out at a pressure in the range of atmospheric pressure to 50 psia.