CN103038202B - Ethanol/fuel blends for use as motor fuels - Google Patents

Abstract

Ethanol/fuel blending compositions. The ethanol/fuel blending composition comprises: an ethanol composition comprising at least 92 wt.% ethanol and 95 wppm to 1,000 wppm isopropanol, and a fuel.

Description

Ethanol/fuel blends for use as motor fuel

Cross References to Related Applications

This application is a continuation-in-part of U.S. Application No. 12/852,290, filed August 6, 2010, which claims U.S. Provisional Application No. 61/300,815, filed February 2, 2010, and U.S. Provisional Application No. 61/332,696 filed on May 7, 2010; U.S. Provisional Application No. 61/332,699 filed on May 7, 2010; Priority to U.S. Provisional Application No. 61/346,344 filed on 19, and is a continuation-in-part of U.S. Application No. 12/903,756 filed on October 13, 2010, which claims Priority to US Provisional Application No. 61/332,726 and US Provisional Application No. 61/300,815, filed February 2, 2010, the entire contents and disclosure of which are hereby incorporated by reference.

field of invention

The present invention generally relates to methods of producing and/or purifying ethanol for use in fuel blends, particularly ethanol fuel blend compositions.

Background of the invention

Ethanol is conventionally produced from petrochemical feedstocks such as oil, natural gas or coal, from feedstock intermediates such as synthesis gas, or from starchy or cellulosic materials such as corn or sugar cane. Conventional methods for the production of ethanol from petrochemical feedstocks as well as from cellulosic materials include acid-catalyzed hydration of ethylene, homologation of methanol, direct alcohol synthesis, and Fischer-Tropsch synthesis. Instability in petrochemical feedstock prices contributes to fluctuations in the cost of conventionally produced ethanol, which makes the need for alternative sources of ethanol production greater than ever when feedstock prices rise. The starchy material as well as the cellulosic material is converted to ethanol by fermentation. However, fermentation is commonly used for the consumer production of ethanol for fuel or consumption. Furthermore, fermentation of starchy or cellulosic materials competes with food sources and imposes limits on the amount of ethanol that can be produced for fuel use.

With regard to the use of ethanol produced by fermentation, the International Monetary Fund observed in 2008 that while such fuels accounted for 1.5 percent of the global liquid fuel supply that year, they represented nearly half of the increase in food crop consumption, largely due to It is caused by the use of corn-based ethanol in the United States. In 2011, 40 percent of the US corn crop will go into motor fuel. Furthermore, this fact is considered to have played a role in the rise in food prices.

Anhydrous or substantially anhydrous ethanol is often preferred for fuel applications. However, anhydrous ethanol or substantially anhydrous ethanol is generally difficult to obtain by conventional hydrogenation and separation methods. For example, ethanol and water produced in conventional hydrogenation reactions can form binary azeotropes. The azeotrope contains about 95% ethanol and about 5% water. Because the boiling point of this azeotrope (78°C) is just slightly lower than that of pure ethanol (78.4°C), it is difficult to obtain anhydrous or substantially anhydrous ethanol compositions from crude ethanol compositions by simple, conventional distillation.

Conventional ethanol compositions formed by the methods described above contain impurities that must be removed. For example, U.S. Patent No. 5,488,185 utilizes petrochemical feedstocks and relates to either an ethylene stream containing ethane as an impurity or a propylene stream containing propane as an impurity that is hydrated with water vapor, respectively, in the presence of a hydration catalyst to produce ethanol or isopropanol. The gaseous product stream is subjected to adsorption after the alcohol is removed, producing either an ethylene-rich stream or a propylene-rich stream. The ethylene-rich stream or the propylene-rich stream is recycled to the hydration reactor.

US Patent Nos. 5,185,481 and 5,284,983 relate to conventional fermentation processes for the production of ethanol. The ethanol composition produced contains impurities such as methanol, acetaldehyde, n-propanol, n-butanol, ethyl acetate, 3-methylbutanol, diethyl ether, acetone, sec-butanol, and crotonaldehyde. These references also disclose the separation process of treating aqueous crude ethanol with an extraction solvent comprising liquid carbon dioxide or supercritical carbon dioxide.

US Patent Nos. 5,445,716; 5,800,681 and 5,415,741 relate to methods of separating mixtures of ethanol and isopropanol. It is difficult to separate ethanol from isopropanol by conventional distillation or rectification because of their close boiling points. Ethanol can be easily separated from isopropanol by extractive distillation. Effective extractants are dipentene, anisole and ethylbenzene. The mixtures in these references contain significant amounts of isopropanol, for example at least 21.5 wt.% isopropanol.

In addition, US Patent No. 5,858,031 relates to a method of enhancing the visibility of flames produced by aqueous alcohol-based fuel compositions during free combustion in air. The fuel comprises about 10%-30% by volume water, and about 70%-90% by volume alcohol mixture (including ethanol and isopropanol), wherein ethanol comprises about 24%-83% by volume of the fuel composition. The method includes providing a fuel composition having an amount of isopropanol of about 7% to 60% by volume, wherein the volume ratio of isopropanol to ethanol in the fuel is not more than 2:1.

While conventional methods can produce and/or purify ethanol compositions, these methods rely on petrochemical feedstocks or fermentation techniques to produce ethanol compositions.

Therefore, there is a need for an ethanol production process that can be used to produce ethanol/fuel blend compositions that does not rely on petrochemical feedstocks and that does not use fermentation techniques.

Summary of the invention

In one embodiment, the present invention is directed to an ethanol/fuel blend composition comprising an ethanol composition and a fuel. The ethanol composition comprises ethanol and isopropanol. Preferably, the ethanol composition comprises at least 92 wt.% ethanol, and 95 wppm to 1,000 wppm isopropanol. The ethanol composition is of high purity and may also contain less than 1 wt.% of one or more organic impurities. These organic impurities may include, for example, acetaldehyde, acetic acid, diethylacetal, ethyl acetate, n-propanol, butanol, 2-butanol, isobutanol, and mixtures thereof. For example, the ethanol composition may contain less than 10 wppm acetaldehyde, less than 10 wppm diethyl acetal, and/or less than 300 wppm _C4 - _C5 alcohol. In other embodiments, the ethanol composition is substantially free of benzene, methanol, and/or _C5 alcohols. In other embodiments, the ethanol composition comprises less than 1 vol.% water.

In another embodiment, the present invention is directed to an ethanol/fuel blend composition comprising an ethanol composition comprising ethanol, isopropanol, n-propanol, and at least 1.96 vol. % fuel denaturant, and unleaded gasoline. The ethanol composition comprises at least 95 wt.% ethanol and at least 95 wppm isopropanol. In another embodiment, isopropanol is present in an amount less than 1000 wppm. Preferably, the weight ratio of isopropanol to n-propanol is 1:1-1:2. Isopropanol may be present in an amount of less than 1000 wppm and/or n-propanol may be present in an amount of less than 270 wppm. In other embodiments, the ethanol/fuel blending composition comprises less than 1 vol.% water.

In yet another embodiment, the present invention is directed to an ethanol/fuel blend composition comprising an ethanol composition comprising ethanol, isopropanol, n-propanol, and at least 1.96 vol.% fuel denaturant, and ultra-low sulfur diesel fuel. The ethanol composition comprises at least 95 wt.% ethanol and at least 95 wppm isopropanol. In another embodiment, isopropanol is present in an amount less than 1000 wppm. Preferably, the weight ratio of isopropanol to n-propanol is 1:1-1:2. Isopropanol may be present in an amount of less than 1000 wppm and/or n-propanol may be present in an amount of less than 270 wppm. In other embodiments, the ethanol/fuel blending composition comprises less than 1 vol.% water.

Description of drawings

The present invention is described in detail below with reference to the accompanying drawings, in which like numerals designate like parts.

Figure 1 is a schematic diagram of a hydrogenation system according to one embodiment of the present invention.

Figure 2 is a schematic diagram of a reaction zone according to one embodiment of the present invention.

Figure 3 is a graph showing the isopropanol content of several conventional ethanol compositions.

Figure 4A is a schematic diagram of a hydrogenation system having a fourth column according to one embodiment of the invention.

Figure 4B is a schematic diagram of a hydrogenation system having a molecular sieve unit according to one embodiment of the present invention.

Detailed description of the invention

definition

As permitted by ASTM D4806, "permitted denaturants" are natural gasoline, gasoline blends, and unleaded gasoline.

"Diesel fuel" means a mixture of C ₉ -C ₂₄ hydrocarbons comprising about 50% to about 95 vol.% aliphatic hydrocarbons (of which about 0 vol.% to about 50 vol.% are naphthenes), about 0 vol.% - about 5 vol.% olefins, and about 5 vol.% to about 50 vol.% aromatics, and have a boiling point of about 280°F (138°C) to 750°F (399°C).

"Denaturant" means one or more substances added to ethanol in accordance with a regulatory agency-approved recipe to render it unfit for consumption and thereby prevent the imposition of taxes on beverage alcohol.

"Natural gasoline" means a natural gas liquid having a vapor pressure between natural gas condensate and liquefied petroleum gas and a boiling point in the gasoline range. Natural gasoline is liquid at ambient pressure and temperature, can be used to denature ethanol and is an acceptable denaturant for denatured fuel ethanol.

"Fischer-Tropsch derived fuel" means a fuel comprising about 90 vol.% to 100 vol.% aliphatic hydrocarbons, about 0 vol.% to about 1 vol.% olefins, and about 0 vol.% to 10 vol.% aromatics.

"Fuel" means, but is not limited to, gasoline, diesel fuel, ULSD, kerosene, jet fuel, biofuel blends (such as biodiesel), Fischer-Tropsch derived fuels, other fuels derived from petroleum or non-petroleum feedstocks, and any of the foregoing composition or concoction.

"Fuel additive" means one or more substances added to a fuel or fuel blend to improve performance or to meet governmental or established regulations. Examples of additives that may be included in minor amounts include, but are not limited to, oxygenates, detergents, dispersants, lubricants, cetane number improvers, cold flow improvers, metal deactivators, demulsifiers, defoamers, dyes , corrosion inhibitors, etc.

"Jet fuel" means a fuel comprising from about 0 vol.% to about 25 vol.% aromatic moieties, from about 0 vol.% to about 25 vol.% naphthenic moieties, and from about 0 vol.% to about 5 vol.% olefinic moieties.

"Gasoline" means a mixture of hydrocarbons boiling at atmospheric pressure from about 77°F (25°C) to about 437°F (225°C). And contains a mixture of paraffins, naphthenes, olefins and aromatics in major amounts, and additives in minor or minor amounts, including oxygenates, detergents, dyes, corrosion inhibitors, etc.

"Gasoline blend" means a blend commonly available in petroleum refineries. Such blendstocks include, but are not limited to, alkylate streams, catalytically cracked gasoline streams (such as cracked naphtha); aromatic saturated gasoline streams, light straight-run gasoline streams, heavy straight-run gasoline streams, degassed Hexanizer bottoms stream, dehexanizer overhead stream, hydrocracker topped light naphtha, reformate, toluene and butane streams. The alkylate stream is typically obtained by polymerizing isobutane with lower olefinic compounds such as butenes and propylene over acidic catalysts such as sulfuric acid, hydrofluoric acid or aluminum chloride. Catalytically cracked gasoline streams are typically produced by fluid catalytic crackers (FCC) or thermal catalytic crackers (TCC). Light and heavy straight-run gasoline streams are typically obtained by atmospheric distillation of crude oil. Reformate streams are typically produced by catalytic reforming to convert naphtha (typically of low octane) into high octane liquid products.

"Kerosene" means a fuel comprising from about 5 vol.% to about 50 vol.% aromatic fractions, from about 0 vol.% to about 50 vol.% naphthenic fractions, and from about 0 vol.% to about 5 vol.% olefinic fractions.

"Ultra Low Sulfur Diesel" (ULSD) refers to diesel fuel having a maximum sulfur content of 15 ppm.

"Unleaded gasoline" is gasoline suitable for use as a fuel in spark-ignition internal combustion engines that has not been treated with lead compounds (see ASTM D4814).

The present invention relates to methods of recovering finished ethanol compositions produced by hydrogenation processes to form ethanol/fuel blending compositions, and to ethanol/fuel blending compositions. The hydrogenation method comprises hydrogenating acetic acid in the presence of a catalyst. The hydrogenation process produces a caide ethanol product that differs from the composition of caide ethanol produced by other ethanol production processes. For example, the crude ethanol composition produced by the fermentation process has a low ethanol content. The caide ethanol composition produced from petrochemical feedstocks contains other alcohols, particularly methanol, n-propanol, and higher alcohols. The caide ethanol product produced by the hydrogenation of acetic acid is preferably separated to remove impurities and recover the finished ethanol composition.

The ethanol composition of the present invention, in one embodiment, comprises a major portion of ethanol and a minor portion of isopropanol. The ethanol composition is mainly ethanol, containing 92 wt.%-96 wt.%, such as 93 wt.%-96 wt.% or 95 wt.%-96 wt.% ethanol. Preferably, the ethanol composition contains at least 92 wt.% ethanol, such as at least 93 wt.% or at least 95 wt.%. It is possible to obtain higher amounts of ethanol, such as absolute ethanol, by further removing water from the ethanol composition. Isopropanol may be present in an amount from 95 wppm to 1,000 wppm, eg, from 110 wppm to 800 wppm or from 110 wppm to 400 wppm. In terms of lower limits, in one embodiment the ethanol composition comprises at least 95 wppm, eg at least 110 wppm or at least 150 wppm isopropanol. In terms of upper limits, in one embodiment the ethanol composition comprises less than 1,000 wppm, eg, less than 800 wppm or less than 400 wppm isopropanol. In contrast, Figure 3 shows the isopropanol levels for 176 conventional ethanol compositions. These ethanol compositions are obtained from various conventional sources and techniques such as sugar cane fermentation, molasses fermentation and Fischer-Tropsch synthesis. As shown in Figure 3, each of these conventional ethanol compositions had very low concentrations of isopropanol, and none contained isopropanol in amounts greater than 94 wppm.

In one embodiment, the ethanol composition further comprises water, eg, water in an amount of less than 8 wt.%, less than 5 wt.%, or less than 2 wt.%. In another embodiment, the weight ratio of isopropanol to water in the ethanol composition is 1:80-1:800, such as 1:100-1:500. In one embodiment, the ethanol composition is substantially free of other detectable compounds such as methanol, benzene and/or higher alcohols such as C4 ₊ alcohols. In some embodiments, the ethanol composition may include minor amounts of other impurities, such as those described in Table 7 below.

In another embodiment, the present invention is directed to an ethanol composition comprising ethanol and at least two other alcohols. The at least two other alcohols may be selected from n-propanol, isopropanol, butanol, 2-butanol and isobutanol. Preferably, one of said at least two other alcohols is isopropanol. In these embodiments, isopropanol is present in an amount of at least 95 wppm, such as at least 110 wppm or at least 150 wppm. In a preferred embodiment, the at least two other alcohols are present in total in an amount of less than 1 wt.% when the weight percentages of the at least two other alcohols are added together.

While not being bound by theory, it is believed that isopropanol is formed during the hydrogenation of acetic acid. For example, isopropanol can be formed by hydrogenation of acetone. Acetone can be produced by ketation of acetic acid. n-Propanol, if present in the ethanol composition, is believed to be formed from impurities in the acetic acid feed. The ethanol composition of the present invention preferably comprises n-propanol in an amount of less than 0.5 wt.%, eg less than 0.1 wt.% or less than 0.05 wt.% n-propanol. Optionally, the ethanol compositions of the present invention may preferably have less n-propanol than isopropanol. Ethanol compositions formed by the methods of the present invention contain higher amounts of in situ formed isopropanol than conventional ethanol compositions. Preferably, in the ethanol composition of the present invention, the amount of n-propanol is less than the amount of isopropanol, for example 10% less than the amount of isopropanol or 50% less than the amount of isopropanol. In addition, in one embodiment, the weight ratio of isopropanol to n-propanol in the ethanol composition of the present invention may be 0.1:1-10:1, such as 0.5:1-10:1, 1:1-5:1 Or 1:1-2:1. As a limit, the weight ratio of isopropanol to n-propanol may be at least 0.5:1, such as at least 1:1, at least 1.5:1, at least 2:1, at least 5:1 or at least 10:1. In conventional ethanol production processes, isopropanol is typically not present in the above amounts. Thus, the weight ratio of isopropanol or n-propanol favors more n-propanol, for example greater than 10:1.

In one embodiment of the invention, isopropanol is preferably not added to the finished ethanol composition after ethanol separation and recovery. The isopropanol formed during the hydrogenation of acetic acid can be carried along with the ethanol during the separation.

Furthermore, conventional hydrogenation reactions often form higher amounts of acetaldehyde compared to isopropanol. The ethanol compositions of the present invention contain low amounts of acetaldehyde, as well as other acetal compounds. Preferably, the amount of acetaldehyde is less than the amount of isopropanol in the ethanol composition of the present invention. For example, the amount of acetaldehyde may be less than 50% of the amount of isopropanol, such as less than 10% of the amount of isopropanol or less than 5% of the amount of isopropanol. A further weight ratio of isopropanol to acetaldehyde in the ethanol composition of the present invention may be 1:100-1:1000, for example 1:100-1:500.

In one embodiment, the ethanol composition of the present invention comprises a minor amount of organic impurities. These organic impurities may include acetaldehyde, acetic acid, diethyl acetal, ethyl acetate, n-propanol, methanol, butanol, 2-butanol, isobutanol, isoamyl alcohol, pentanol, benzene and/or their mixture. Advantageously, in one embodiment the ethanol composition comprises less than 1 wt.%, eg less than 0.75 wt.% or less than 0.5 wt.% of organic impurities. Depending on the amount of these organic impurities, the impurities may have detrimental effects on the ethanol composition. For example, other alcohols in the caide ethanol composition can be esterified with acetic acid to form other esters. In addition, isobutanol, isoamyl alcohol, and 2-methyl-1-butanol ("pentanol") were found to contribute to residual odor in ethanol and ethyl acetate compositions.

In preferred embodiments, the ethanol composition is substantially free of methanol and may contain less than 10 wppm, such as less than 1 wppm, methanol. Furthermore, in preferred embodiments, the ethanol composition is substantially free of _C5 alcohols and may comprise less than 10 wppm, such as less than 1 wppm, _C5 alcohols.

Benzene, dioxane and cyanide are known to present toxicity problems in ethanol compositions. Typically, cyanide is produced from fermentation processes using cassava as a feedstock. The ethanol compositions of the present invention contain low amounts of these components. Preferably, the ethanol composition contains undetectable amounts of benzene, dioxane and cyanide.

Hydrogenation process

Turning now to the production of crude ethanol compositions, typically, acetic acid is hydrogenated to form ethanol and water as shown in the following reaction:

As noted in Table 1 below, in addition to water and ethanol, other compounds may be formed during the hydrogenation of acetic acid.

Suitable hydrogenation catalysts include catalysts that optionally include a first metal and optionally include one or more of a second metal, a third metal, or an additional metal on a catalyst support. The first and optional second and third metals may be selected from: IB, IB, IIIB, IVB, VB, VIB, VIIB, VIII transition metals, lanthanides, actinides or from IIIA, IVA, VA and metals of any group in group VIA. Preferred metal combinations for some exemplary catalyst compositions include platinum/tin, platinum/ruthenium, platinum/rhenium, palladium/ruthenium, palladium/rhenium, cobalt/palladium, cobalt/platinum, cobalt/chromium, cobalt/ruthenium, Silver/palladium, copper/palladium, nickel/palladium, gold/palladium, ruthenium/rhenium and ruthenium/iron. Exemplary catalysts are also described in US Patent No. 7,608,744 and US Publication No. 2010/0029995, which are hereby incorporated by reference in their entireties. Additional catalysts are described in U.S. Application No. 12/698,968, entitled "Catalysts for Making Ethanol from Acetic Acid," filed February 2, 2010, which is incorporated herein by reference in its entirety.

In an exemplary embodiment, the catalyst comprises a first metal selected from the group consisting of copper, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, titanium, zinc, chromium, rhenium, molybdenum, and tungsten. Preferably, the first metal is selected from platinum, palladium, cobalt, nickel and ruthenium. More preferably, the first metal is selected from platinum and palladium. When the first metal comprises platinum, the catalyst preferably comprises platinum in an amount of less than 5 wt.%, such as less than 3 wt.% or less than 1 wt.%, due to the high demand for platinum.

As indicated above, the catalyst optionally also includes a second metal, which can generally function as a promoter. If present, the second metal is preferably selected from copper, molybdenum, tin, chromium, iron, cobalt, vanadium, tungsten, palladium, platinum, lanthanum, cerium, manganese, ruthenium, rhenium, gold and nickel. More preferably, the second metal is selected from copper, tin, cobalt, rhenium and nickel. More preferably, the second metal is selected from tin and rhenium.

If the catalyst comprises two or more metals, such as a first metal and a second metal, the first metal is optionally present in the catalyst in an amount of 0.1-10 wt.%, such as 0.1-5 wt.% or 0.1-3 wt.%. exist. The second metal is preferably present in an amount of 0.1-20 wt.%, eg 0.1-10 wt.% or 0.1-5 wt.%. For catalysts comprising two or more metals, the two or more metals may be alloyed with each other or may comprise non-alloyed metal solid solutions or mixtures.

The preferred metal ratios can vary depending on the metals used in the catalyst. In some exemplary embodiments, the molar ratio of the first metal to the second metal is preferably 10:1-1:10, such as 4:1-1:4, 2:1-1:2, 1.5:1-1 :1.5 or 1.1:1-1:1.1.

The catalyst may also comprise a third metal selected from any of the metals listed above with respect to the first or second metal, so long as the third metal is different from the first and second metals. In preferred aspects, the third metal is selected from cobalt, palladium, ruthenium, copper, zinc, platinum, tin and rhenium. More preferably, the third metal is selected from cobalt, palladium and ruthenium. When present, the total weight of the third metal is preferably 0.05-4 wt.%, such as 0.1-3 wt.% or 0.1-2 wt.%.

Exemplary catalysts include, in addition to one or more metals, a support or a modified support, which refers to a support that includes a support material and a support modifier that adjusts the acidity of the support material. The total weight of the support or modified support is preferably 75 wt.% to 99.9 wt.%, such as 78 wt.% to 97 wt.% or 80 wt.% to 95 wt.%, based on the total weight of the catalyst. In a preferred embodiment using a modified support, the support modifier is based on the total weight of the catalyst at 0.1wt.%-50wt.%, such as 0.2wt.%-25wt.%, 0.5wt.%-15wt.% or 1wt .%-8wt.% is present.

Suitable support materials may include, for example, stable metal oxide-based supports or ceramic-based supports. Preferred supports include siliceous supports such as silica, silica/alumina, Group IIA silicates such as calcium metasilicate, fumed silica, high purity silica, and mixtures thereof. Other supports may include, but are not limited to, iron oxide, alumina, titania, zirconia, magnesia, carbon, graphite, high surface area graphitized carbon, activated carbon, and mixtures thereof.

In the production of ethanol, catalyst supports can be modified with support modifiers. Preferably, the support modifier is a basic modifier with low or no volatility. Such basic modifiers may for example be selected from: (i) alkaline earth metal oxides, (ii) alkali metal oxides, (iii) alkaline earth metal metasilicates, (iv) alkali metal metasilicates, (v ) Group IIB metal oxides, (vi) Group IIB metal metasilicates, (vii) Group IIIB metal oxides, (viii) Group IIIB metal metasilicates, and mixtures thereof. In addition to oxides and metasilicates, other types of modifiers including nitrates, nitrites, acetates and lactates may be used. Preferably, the support modifier is selected from oxides and metasilicates of any element in sodium, potassium, magnesium, calcium, scandium, yttrium and zinc, and any mixture of the foregoing. Preferably, the support modifier is calcium silicate, and more preferably calcium metasilicate (CaSiO ₃ ). If the support modifier comprises calcium metasilicate, at least a portion of the calcium metasilicate is preferably in crystalline form.

A preferred silica support material is SS61138 high surface area (HSA) silica catalyst support from Saint-Gobain NorPro. Saint-Gobain NorProSS61138 silica contains about 95 wt.% high surface area silica; surface area about 250 m ² /g; median pore diameter about 12 nm; average of about 1.0 cm ³ /g as measured by mercury intrusion porosimetry Pore volume and bulk density of about 0.352 g/cm ³ (22 lb/ft ³ ).

A preferred silica/alumina support material is KA-160 (Sud Chemie) silica spheres having a nominal diameter of about 5 mm, a density of about 0.562 g/ml, an absorption of about 0.583 g _H2O /g support rate, a surface area of about 160-175 m ² /g and a pore volume of about 0.68 ml/g.

Those skilled in the art will appreciate that the support material is selected such that the catalyst system has suitable activity, selectivity, and robustness under the process conditions used to produce ethanol.

The metal of the catalyst can be dispersed throughout the support, coated on the outer surface of the support (eggshell) or decorated on the support surface.

Catalyst compositions suitable for use in the present invention are preferably formed by metal impregnation of the modified support, although other methods such as chemical vapor deposition may also be used. Such impregnation techniques are described in the above-mentioned US Patent No. 7,608,744, US Publication No. 2010/0029995, and US Application No. 12/698,968, which are hereby incorporated by reference in their entirety.

As will be readily appreciated by those skilled in the art, some embodiments of the method of hydrogenating acetic acid to form ethanol according to an embodiment of the present invention may include various configurations using fixed bed reactors or fluidized bed reactors. In many embodiments of the invention, "adiabatic" reactors may be used; that is, with little or no internal plumbing through the reaction zone to add or remove heat. In other embodiments, one reactor or multiple reactors with radial flow may be used, or a series of reactors with or without heat exchange, cooling, or introduction of additional feeds may be used. Alternatively, a shell and tube reactor equipped with a heat transfer medium can be used. In many cases, the reaction zone can be housed in a single vessel or in a series of vessels with heat exchangers in between.

In a preferred embodiment, the catalyst is used in a fixed bed reactor, eg in the shape of a tube or conduit, through which the reactants, typically in vapor form, are passed or passed. Other reactors may be used, such as fluidized bed or ebullating bed reactors. In some cases, hydrogenation catalysts may be used in conjunction with inert materials to regulate the pressure drop of the reactant stream through the catalyst bed and the contact time of the reactant compounds with the catalyst particles.

The hydrogenation reaction can be carried out in liquid or gas phase. Preferably, the reaction is carried out in the gas phase under the following conditions. The reaction temperature may be 125°C-350°C, such as 200°C-325°C, 225°C-300°C or 250°C-300°C. The pressure may be 10KPa-3000KPa (about 1.5-435psi), such as 50KPa-2300KPa or 100KPa-1500KPa. The reactants may be fed to the reactor at a gas hourly space velocity (GHSV) greater than 500 hr ⁻¹ , such as greater than 1000 hr ⁻¹ , greater than 2500 hr ⁻¹ , or even greater than 5000 hr ⁻¹ . In terms of ranges, the GHSV can be from 50 hr ⁻¹ to 50,000 hr ⁻¹ , such as 500 hr ^{−1 to} 30,000 hr ⁻¹ , 1000 hr ⁻¹ to 10,000 hr ⁻¹ , or 1000 hr ⁻¹ to 6500 hr ⁻¹ .

The hydrogenation is optionally carried out at the selected GHSV at a pressure just sufficient to overcome the pressure drop across the catalytic bed, although not limited to the use of higher pressures, it is understood that at high space velocities such as 5000 ^hr or 6,500 hr ^-1 may experience a considerable pressure drop across the reactor bed.

Although the reaction consumes 2 moles of hydrogen per mole of acetic acid to produce 1 mole of ethanol, the actual molar ratio of hydrogen to acetic acid in the feed stream can range from about 100:1 to 1:100, such as 50:1 to 1:50, 20:1 1-1:2 or 12:1-1:1. Most preferably, the molar ratio of hydrogen to acetic acid is greater than 2:1, such as greater than 4:1 or greater than 8:1.

Contact or residence times can also vary widely, depending on variables such as the amount of acetic acid, catalyst, reactor, temperature and pressure. When using catalyst systems other than fixed beds, typical contact times range from fractions of a second to greater than several hours, at least for gas phase reactions, preferred contact times being 0.1-100 seconds, such as 0.3-80 seconds or 0.4-30 seconds Second.

The feedstocks, acetic acid and hydrogen used in connection with the methods of the present invention may be derived from any suitable source, including natural gas, petroleum, coal, biomass, and the like. As examples, acetic acid can be produced by methanol carbonylation, acetaldehyde oxidation, ethylene oxidation, oxidative fermentation, and anaerobic fermentation. As oil and gas prices fluctuate and become more or less expensive, methods for producing acetic acid and intermediates such as methanol and carbon monoxide from alternative carbon sources have gradually attracted attention. In particular, the production of acetic acid from synthetic gas ("syngas") derived from any available carbon source may become advantageous when petroleum is relatively expensive compared to natural gas. For example, US Patent No. 6,232,352, the disclosure of which is incorporated herein by reference, teaches a method of retrofitting a methanol plant to produce acetic acid. By retrofitting the methanol plant, the substantial capital costs associated with CO generation are significantly reduced or largely eliminated for new acetic acid plants. All or part of the synthesis gas is diverted from the methanol synthesis loop and fed to a separator unit to recover CO and hydrogen, which are then used to produce acetic acid. In addition to acetic acid, this method can also be used to produce hydrogen which can be utilized in connection with the present invention.

Methanol carbonylation processes suitable for acetic acid production are described in U.S. Patent Nos. 7,208,624, 7,115,772, 7,005,541, 6,657,078, 6,627,770, 6,143,930, 5,599,976, 5,144,068, 5,026,908, 5,001,259, and 4,994,608, the disclosures of which are incorporated herein by reference. Optionally, ethanol production can be integrated with this methanol carbonylation process.

US Patent No. RE35,377 (also incorporated herein by reference) provides a method for producing methanol by converting carbonaceous materials such as oil, coal, natural gas, and biomass materials. The process includes hydrogasifying solid and/or liquid carbonaceous materials to obtain a process gas that is steam pyrolyzed with additional natural gas to form synthesis gas. This synthesis gas is converted to methanol which can be carbonylated to acetic acid. This process also produces hydrogen which can be used as described above in relation to the present invention. US Patent No. 5,821,111 and US Patent No. 6,685,754 disclose a method of converting waste biomass to syngas by gasification, the disclosures of which are incorporated herein by reference.

In an optional embodiment, the acetic acid fed to the hydrogenation reaction may also contain other carboxylic acids and anhydrides, as well as acetaldehyde and acetone. Preferably, a suitable acetic acid feed stream comprises one or more compounds selected from the group consisting of acetic acid, acetic anhydride, acetaldehyde, and mixtures thereof. These other compounds may also be hydrogenated in the process of the invention. In some embodiments, the presence of a carboxylic acid, such as propionic acid or its anhydride, may be beneficial in propanol production.

Alternatively, acetic acid in vapor form may be withdrawn directly as a crude product from the flasher of a methanol carbonylation unit of the type described in US Patent No. 6,657,078, which is hereby incorporated by reference in its entirety. For example, the crude vapor product can be fed directly to the ethanol synthesis reaction zone of the present invention without the need to condense acetic acid and light ends or remove water, thereby saving overall process costs.

Acetic acid can be vaporized at the reaction temperature, and the vaporized acetic acid can then be fed with hydrogen either undiluted or diluted with a relatively inert carrier gas such as nitrogen, argon, helium, carbon dioxide, and the like. To run the reaction in the gas phase, the temperature in the system should be controlled so that it does not drop below the dew point of the acetic acid. In one embodiment, acetic acid can be vaporized at a specific pressure at the boiling point of acetic acid, and then the vaporized acetic acid can be further heated to the reactor inlet temperature. In another embodiment, the acetic acid vapor is wetted by passing hydrogen, cycle gas, another suitable gas, or a mixture thereof through the acetic acid at a temperature below the boiling point of the acetic acid to convert the acetic acid to a vapor state. The carrier gas, followed by heating the mixed vapors up to the reactor inlet temperature. Preferably, the acetic acid is converted to vapor by passing hydrogen and/or recycle gas through the acetic acid at a temperature of or below 125°C, followed by heating the combined gaseous streams to the reactor inlet temperature.

In particular, hydrogenation of acetic acid can achieve favorable conversion of acetic acid and favorable selectivity and yield to ethanol. For the purposes of the present invention, the term "conversion" refers to the amount of acetic acid in the feed that is converted to compounds other than acetic acid. Conversions are expressed in mole percent based on acetic acid in the feed. The conversion may be at least 10%, such as at least 20%, at least 40%, at least 50%, at least 60%, at least 70%, or at least 80%. While catalysts with high conversions, eg, at least 80% or at least 90%, are desirable, low conversions may be acceptable in some embodiments where ethanol selectivity is high. Of course, it is well understood that in many cases conversions can be made up by appropriate recycle streams or by using larger reactors, but poor selectivities are more difficult to make up for.

Selectivities are expressed in mole percent based on converted acetic acid. It is understood that each compound converted from acetic acid has an independent selectivity and that selectivity is independent of conversion. For example, if 50 mole percent of the converted acetic acid is converted to ethanol, then the ethanol selectivity is 50%. Preferably, the selectivity of the catalyst to ethoxylates is at least 60%, such as at least 70% or at least 80%. As used herein, the term "ethoxylate" specifically refers to the compounds ethanol, acetaldehyde and ethyl acetate. Preferably, the selectivity to ethanol is at least 80%, such as at least 85% or at least 88%. Preferred embodiments of this hydrogenation process also have low selectivity to undesired products such as methane, ethane and carbon dioxide. The selectivity to these undesired products is preferably less than 4%, such as less than 2% or less than 1%. More preferably, these undesired products are not detectable. The formation of alkanes can be low, ideally less than 2%, less than 1% or less than 0.5% of the acetic acid passing through the catalyst is converted to alkanes which have little value other than as fuel.

The term "productivity" as used herein refers to the grams of a defined product, such as ethanol, formed per hour during hydrogenation based on kilograms of catalyst used. A preferred production rate is at least 200 grams of ethanol per kilogram of catalyst per hour, for example at least 400 grams of ethanol per kilogram of catalyst per hour or at least 600 grams of ethanol per kilogram of catalyst per hour. In terms of ranges, the production rate is preferably 200-3,000 grams of ethanol per kilogram of catalyst per hour, such as 400-2,500 grams of ethanol per kilogram of catalyst per hour or 600-2,000 grams of ethanol per kilogram of catalyst per hour.

In various embodiments, the crude ethanol product produced by the hydrogenation process will typically contain unreacted acetic acid, ethanol, and water prior to any subsequent processing, such as purification and isolation. As used herein, the term "caide ethanol product" refers to any composition comprising 5-70 wt.% ethanol and 5-35 wt.% water. In some exemplary embodiments, the caide ethanol product comprises ethanol in an amount of 5 wt.% to 70 wt.%, such as 10 wt.% to 60 wt.%, or 15 wt.% to 50 wt.%, based on the total weight of the caide ethanol product. Preferably, the crude ethanol product contains at least 10 wt.% ethanol, at least 15 wt.% ethanol, or at least 20 wt.% ethanol.

Depending on conversion, the caide ethanol product will typically also contain unreacted acetic acid, eg in an amount less than 90 wt.%, eg less than 80 wt.% or less than 70 wt.%. In terms of range, unreacted acetic acid is preferably 0-90 wt.%, such as 5-80 wt.%, 15-70 wt.%, 20-70 wt.%, or 25-65 wt.%. Since water is formed during the reaction, water will typically be present in the caide ethanol product, eg, in an amount of 5-35 wt.%, such as 10-30 wt.% or 10-26 wt.%. Ethyl acetate may also be produced during the hydrogenation of acetic acid or by side reactions, and it may be present, for example, in an amount of 0-20 wt.%, such as 0-15 wt.%, 1-12 wt.%, or 3-10 wt.%. Acetaldehyde may also be produced by side reactions and may be present eg in an amount of 0-10 wt.%, such as 0-3 wt.%, 0.1-3 wt.% or 0.2-2 wt.%.

Other components such as esters, ethers, aldehydes, ketones, alkanes and carbon dioxide, if detectable, may together be present in an amount of less than 10 wt.%, such as less than 6 wt.% or less than 4 wt.%. In terms of ranges, the other components may be present in an amount of 0.1-10 wt.%, such as 0.1-6 wt.% or 0.1-4 wt.%. Exemplary embodiments of crude ethanol composition ranges are provided in Table 1.

purification

Figure 1 shows a hydrogenation system 100 suitable for hydrogenation of acetic acid and separation of ethanol from a crude reaction mixture, according to one embodiment of the present invention. System 100 includes reaction zone 101 and distillation zone 102 . Reaction zone 101 comprises a reactor 103 , a hydrogen feed line 104 and an acetic acid feed line 105 . Distillation zone 102 includes flasher 106 , first column 107 , second column 108 , third column 109 and fourth column 123 . Hydrogen and acetic acid are fed to vaporizer 110 via lines 104 and 105, respectively, to generate a vapor feed stream in line 111 leading to reactor 103. In one embodiment, lines 104 and 105 can be combined and co-fed to vaporizer 110, for example, in one stream containing both hydrogen and acetic acid. The temperature of the vapor feed stream in line 111 is preferably from 100°C to 350°C, eg, from 120°C to 310°C or from 150°C to 300°C. As shown in Figure 1, any feed that is not vaporized is removed from vaporizer 110 and may be recycled thereto. Additionally, while FIG. 1 shows line 111 leading to the top of reactor 103 , line 111 may lead to the side, top, or bottom of reactor 103 . Other modifications and additional components of reaction zone 101 are described in Figure 2 below.

Reactor 103 contains a catalyst for hydrogenating a carboxylic acid, preferably acetic acid. In one embodiment, one or more guard beds (not shown) may be used to protect the catalyst from toxics or undesired impurities contained in the feed or return/recycle streams. Such guard beds can be used in vapor or liquid streams. Suitable guard bed materials are known in the art and include, for example, carbon, silica, alumina, ceramics or resins. In one aspect, the guard bed media is functionalized to trap specific species such as sulfur or halogens. A caide ethanol product is preferably withdrawn from reactor 103 via line 112 continuously during the hydrogenation process. The crude ethanol product may be condensed and fed to flasher 106, which in turn provides a vapor stream and a liquid stream. In one embodiment, flasher 106 preferably operates at a temperature of 50°C to 500°C, eg, 70°C to 400°C or 100°C to 350°C. In one embodiment, the pressure of the flasher 106 is preferably 50KPa-2000KPa, such as 75KPa-1500KPa or 100-1000KPa. In a preferred embodiment, the temperature and pressure of the flasher are similar to those of reactor 103.

The vapor stream exiting flasher 106 may contain hydrogen and hydrocarbons, which may be purged and/or returned to reaction zone 101 via line 113 . As shown in FIG. 1 , the return portion of the vapor stream passes through compressor 114 and is combined with the hydrogen feed, co-fed to vaporizer 110 .

Liquid from flasher 106 is withdrawn and pumped as a feed composition via line 115 to the side of first column 107 (also referred to as an acid separation column). The contents of line 115 will typically be substantially similar to the product obtained directly from the reactor, and indeed may also be referred to as the caide ethanol product. However, the feed composition in line 115 is preferably substantially free of hydrogen, carbon dioxide, methane or ethane, which are removed via flasher 106 . Exemplary compositions of the liquid in line 115 are provided in Table 2. It should be understood that liquid line 115 may contain other components (not listed) such as those in the feed.

Amounts less than (<) indicated in tables throughout this application are preferably absent and if present may be present in trace amounts or in amounts greater than 0.0001 wt.%.

"Other esters" in Table 2 may include, but are not limited to, ethyl propionate, methyl acetate, isopropyl acetate, n-propyl acetate, n-butyl acetate, or mixtures thereof. "Other ethers" in Table 2 may include, but not limited to, diethyl ether, methyl ethyl ether, isobutyl ethyl ether, or mixtures thereof. "Other alcohols" in Table 2 may include, but are not limited to, methanol, isopropanol, n-propanol, n-butanol, or mixtures thereof. In one embodiment, a feed composition such as line 115 may comprise propanol such as isopropanol and/or n-propanol in an amount of 0.001-0.1 wt.%, 0.001-0.05 wt.%, or 0.001-0.03 wt.%. . It is understood that these other components may be carried in any of the distillate or residue streams described herein, and unless otherwise stated, will not be further described herein.

When the content of acetic acid in line 115 is less than 5 wt.%, acid separation column 107 can be skipped and line 115 can be introduced directly to second column 108 (also referred to herein as light ends column).

In the embodiment shown in FIG. 1 , line 115 is introduced into the lower portion of first column 107, such as the lower half or third. In first column 107, unreacted acetic acid, some of the water and other heavies, if present, are removed from the composition in line 115 and preferably continuously as a residue. Some or all of the residue may be returned and/or recycled back to reaction zone 101 via line 116 . The first column 107 also forms an overhead, which is withdrawn in line 117 and which can be distributed, for example, at 10:1-1:10, such as 3:1-1:3 or 1:2-2: 1 ratio condensation and reflux.

Any of columns 107, 108, 109 or 123 may comprise any distillation column capable of separation and/or purification. The column preferably comprises a tray column having 1-150 trays, eg 10-100 trays, 20-95 trays or 30-75 trays. The trays may be sieve trays, fixed valve trays, moving valve trays, or any other suitable design known in the art. In other embodiments, packed columns may be used. For packed columns, structured packing or random packing can be used. The columns or packing can be arranged as a continuous column or they can be arranged as two or more columns such that the vapor from the first stage enters the second stage while the liquid from the second stage enters the second stage. For a while, wait.

The associated condensers and liquid separation vessels that can be used with each distillation column can be of any conventional design and are simplified in Figure 1 . As shown in Figure 1, heat can be supplied to the bottom of each column or to a circulating bottoms stream via a heat exchanger or reboiler. In some embodiments, other types of reboilers, such as internal reboilers, may also be used. The heat provided to the reboiler may be derived from any heat generated during a process integrated with the reboiler or from an external source such as another heat-generating chemical process or a boiler. Although one reactor and one flasher are shown in Figure 1, additional reactors, flashers, condensers, heating elements and other components may be used in embodiments of the present invention. As can be appreciated by those skilled in the art, it is also possible to combine various condensers, pumps, compressors, reboilers, drums, valves, connectors, separation vessels, etc. that are commonly used in carrying out chemical processes and use in the method of the present invention.

The temperatures and pressures used in any column can vary. As a practical matter, pressures from 10 KPa to 3000 KPa may generally be used in these regions, although in some embodiments subatmospheric pressures as well as superatmospheric pressures may be used. The temperature in each zone will generally be in the range between the boiling point of the composition removed as distillate and the composition removed as residue. Those skilled in the art will recognize that the temperature at a given location in an operating distillation column depends on the composition of the feed at that location and the pressure of the column. Furthermore, feed rates may vary depending on the scale of the production process and, if described, may generally refer to feed weight ratios.

When column 107 is operated at normal atmospheric pressure, the temperature of the residue exiting column 107 in line 116 is preferably from 95°C to 120°C, eg 105°C to 117°C or 110°C to 115°C. The temperature of the distillate exiting column 107 in line 117 is preferably from 70°C to 110°C, eg, from 75°C to 95°C or from 80°C to 90°C. In other embodiments, the pressure of the first column 107 may be 0.1KPa-510KPa, such as 1KPa-475KPa or 1KPa-375KPa. Exemplary components of the distillate and residue compositions of first column 107 are provided in Table 3 below. It should also be understood that the distillates and residues may also contain other components not listed, such as components in the feed. For convenience, the distillate and residue of the first column may also be referred to as "first distillate" or "first residue". Distillates or residues from other columns may also be referred to with similar numerical modifiers (second, third, etc.) to distinguish them from each other, but such modifiers should not be construed as requiring any particular order of separation .

As shown in Table 3, while not being bound by theory, it has been surprisingly and unexpectedly discovered that when any amount of acetal is detected in the feed to the acid separation column (first column 107), the acetal appears to be present in the The decomposition in this column is such that little or even no detectable amount is present in the distillate and/or residue.

Depending on the reaction conditions, the caide ethanol product exiting reactor 103 in line 112 may comprise ethanol, acetic acid (unconverted), ethyl acetate, and water. After exiting reactor 103, the caide ethanol product may undergo a non-catalyzed equilibrium reaction between the components contained therein before being fed to flasher 106 and/or first column 107. As shown below, this equilibrium reaction tends to drive the crude ethanol product to an equilibrium between ethanol/acetic acid and ethyl acetate/water.

Extended residence times may be encountered where the crude ethanol product is temporarily stored, eg, in storage tanks, before being directed to distillation zone 102 . In general, the longer the residence time between reaction zone 101 and distillation zone 102, the more ethyl acetate is formed. For example, when the residence time between reaction zone 101 and distillation zone 102 is greater than 5 days, significantly more ethyl acetate may be formed at the loss of ethanol. Accordingly, shorter residence times between reaction zone 101 and distillation zone 102 are generally preferred to maximize the amount of ethanol formed. In one embodiment, a storage tank (not shown) is included between reaction zone 101 and distillation zone 102 for temporary storage of liquid components from line 115 for up to 5 days, eg up to 1 day or up to 1 hour. In a preferred embodiment, a tank is not included and the condensed liquid is fed directly to the first distillation column 107 . Additionally, the rate at which non-catalyzed reactions occur can increase as the temperature of the caide ethanol product in line 115 increases, for example. These reaction rates can be particularly problematic at temperatures above 30°C, such as above 40°C or above 50°C. Thus, in one embodiment, the temperature of the liquid component in line 115 or in an optional storage tank is maintained at a temperature of less than 40°C, eg, less than 30°C or less than 20°C. One or more cooling devices may be used to reduce the temperature of the liquid in line 115.

As discussed above, a storage tank (not shown) may be included between reaction zone 101 and distillation zone 102 for temporary storage of the liquid component from line 115, for example, for 1-24 hours, optionally at a temperature of about 21°C, and correspond to the formation of 0.01 wt.%-1.0 wt.% ethyl acetate, respectively. Additionally, the rate at which non-catalyzed reactions occur can increase as the temperature of the caide ethanol product increases. For example, as the temperature of the caide ethanol product in line 115 increases from 4°C to 21°C, the rate of ethyl acetate formation can increase from about 0.01 wt.%/hour to about 0.005 wt.%/hour. Thus, in one embodiment, the temperature of the liquid component in line 115 or in an optional storage tank is maintained at a temperature of less than 21°C, eg, less than 4°C or less than -10°C.

Furthermore, it has been found that the above-mentioned equilibrium reactions may also favor the formation of ethanol in the top region of the first column 107 .

As shown in Figure 1, the distillate from column 107, such as the overhead stream, is optionally condensed and refluxed, preferably at a reflux ratio of 1:5-10:1. The distillate in line 117 preferably contains ethanol, ethyl acetate, and water as well as other impurities, which can be difficult to separate due to the formation of binary and ternary azeotropes.

The first distillate in line 117 is introduced to second column 108 (also referred to as "light ends column"), preferably in the middle portion of column 108, such as the middle half or middle third. As an example, when using a 25-tray column in a column without water extraction, line 117 is introduced at tray 17. In one embodiment, second column 108 may be an extractive distillation column. In such an embodiment, an extractant such as water may be added to the second column 108 . If the extractant comprises water, it can be obtained from an external source or from an internal return/recycle line from one or more other columns.

The second column 108 may be a tray column or a packed column. In one embodiment, the second column 108 is a tray column having 5-70 trays, such as 15-50 trays or 20-45 trays.

Although the temperature and pressure of the second column 108 can vary, the temperature of the second residue exiting the second column 108 in line 118 is preferably from 60°C to 90°C, such as 70°C to 90°C or 80°C when at atmospheric pressure. ℃-90℃. The temperature of the second distillate exiting second column 108 in line 120 is preferably from 50°C to 90°C, eg, from 60°C to 80°C or from 60°C to 70°C. Column 108 can operate at atmospheric pressure. In other embodiments, the pressure of the second column 108 may be 0.1KPa-510KPa, such as 1KPa-475KPa or 1KPa-375KPa. Exemplary components of the distillate and residue compositions of second column 108 are provided in Table 4 below. It is understood that the distillates and residues may also contain other components not listed, such as components in the feed.

The weight ratio of ethanol in the second residue to ethanol in the second distillate is preferably at least 3:1, such as at least 6:1, at least 8:1, at least 10:1 or at least 15:1. The weight ratio of ethyl acetate in the second residue to ethyl acetate in the second distillate is preferably less than 0.4:1, such as less than 0.2:1 or less than 0.1:1. In embodiments using an extraction column with water as the extractant as the second column 108, the weight ratio of ethyl acetate in the second residue to ethyl acetate in the second distillate is close to zero.

As shown, the second residue from the bottom of second column 108 , which comprises ethanol and water, is fed via line 118 to third column 109 (also referred to as the "product column"). More preferably, the second residue in line 118 is introduced into the lower portion of third column 109, such as the lower half or third. Third column 109 recovers ethanol (preferably substantially pure except for azeotropic water content) as a distillate in line 119. The distillate from the third column 109 is preferably refluxed as shown in FIG. 1 , for example, at a reflux ratio of 1:10-10:1 such as 1:3-3:1 or 1:2-2:1. The third residue in line 121 , which preferably consists primarily of water, is preferably removed from system 100 or may be partially returned to any part of system 100 . The third column 109 is preferably a tray column as described above and preferably operates at atmospheric pressure. The temperature of the third distillate exiting third column 109 in line 119 is preferably from 60°C to 110°C, for example from 70°C to 100°C or from 75°C to 95°C. When the column is operated at atmospheric pressure, the temperature of the third residue exiting the third column 109 is preferably from 70°C to 115°C, eg 80°C to 110°C or 85°C to 105°C. Exemplary components of the distillate and residue compositions of third column 109 are provided in Table 5 below. It is to be understood that the distillate and residue may also contain other components not listed, such as components in the feed

The ethanol composition may contain the impurities described above. In some embodiments, the ethanol composition may also include other compounds resulting from the reaction process or the isolation process. These compounds, which may be carried over from the feed or crude reaction product during the distillation, may generally remain in the third distillate in small amounts. For example, the other compounds may be present in an amount of less than 0.1 wt.%, such as less than 0.05 wt.% or less than 0.02 wt.%, based on the total weight of the third distillate composition. In one embodiment, one or more side streams may remove impurities from any of columns 107 , 108 , and/or 109 within system 100 . Impurities are preferably removed from third column 109 using at least one side stream. Impurities may be purged and/or retained within the system 100 .

As described in more detail below, the third distillate in line 119 can be further purified using one or more additional separation systems, such as distillation columns (e.g., finishing columns) or molecular sieves to form an anhydrous ethanol product stream, i.e., " Finished absolute ethanol".

Returning to the second column 108, the second distillate is preferably as shown in Figure 1, for example with a reflux ratio of 1:10-10:1, such as 1:5-5:1 or 1:3-3:1 Perform reflow. The second distillate can be fed via line 120 to a fourth column 123, also referred to as the "acetaldehyde removal column". In fourth column 123 , the second distillate is separated into a fourth distillate comprising acetaldehyde in line 124 and a fourth residue comprising ethyl acetate in line 125 . The fourth distillate is preferably refluxed at a reflux ratio of 1:20-20:1, such as 1:15-15:1 or 1:10-10:1, with a portion of the fourth distillate being returned via line 124 as shown to reaction zone 101. For example, the fourth distillate can be combined with the acetic acid feed, added to evaporator 110 , or added directly to reactor 103 . As shown, the fourth distillate is co-fed to evaporator 110 with acetic acid in feed line 105 . Without being bound by theory, since acetaldehyde can be hydrogenated to form ethanol, recycling the acetaldehyde-containing stream to the reaction zone increases the yield of ethanol and reduces by-product and waste generation. In another embodiment (not shown in the figure), acetaldehyde can be collected and utilized with or without further purification to produce compounds including but not limited to n-butanol, 1,3-butanediol and and/or useful products of crotonaldehyde and derivatives.

The fourth residue of fourth column 123 may be purged via line 125 . The fourth residue mainly contains ethyl acetate and ethanol, which may be suitable as solvent mixtures or in ester production. In a preferred embodiment, acetaldehyde is distilled from the second distillate in the fourth column 123

The material is removed such that there is no detectable amount of acetaldehyde in the residue of column 123.

The fourth column 123 is preferably a tray column as described above and preferably operates at superatmospheric pressure. In one embodiment, the pressure is 120KPa-5000KPa, such as 200KPa-4,500KPa or 400KPa-3000KPa. In a preferred embodiment, fourth column 123 may operate at a higher pressure than the other columns.

The temperature of the fourth distillate exiting fourth column 123 in line 124 is preferably from 60°C to 110°C, eg, from 70°C to 100°C or from 75°C to 95°C. The temperature of the residue exiting the fourth column 125 is preferably from 70°C to 115°C, eg 80°C to 110°C or 85°C to 110°C. Exemplary components of the distillate and residue compositions of fourth column 123 are provided in Table 6 below. It is understood that the distillates and residues may also contain other components not listed, such as components in the feed.

Although one reactor and one flasher are shown in Figure 1 , additional reactors and/or components may be included in various optional embodiments of the invention. Figure 2 shows a hydrogenation system 100' comprising dual reactors 103, 103', dual flashers 106, 106', heat exchanger 130 and preheater 131. In this embodiment, acetic acid in line 105 is heated in heat exchanger 130 with recycled acetic acid in line 116 and recycled acetaldehyde from line 124 and sent to vaporizer 110 via line 132 . The temperature of the contents of line 132 is preferably from 30°C to 150°C, eg, from 50°C to 130°C or from 75°C to 120°C. Hydrogen is fed to vaporizer 110 via line 104 , which forms vaporized stream 111 . The evaporated stream 111 passes through a preheater 131 which further heats the stream 111 to a temperature of preferably 200°C to 300°C, eg 210°C to 275°C or 220°C to 260°C. The heated stream is then fed to the first reactor 103 . To control the reaction exotherm, the crude reaction mixture is removed from the first reactor 103 via line 133 and cooled before being fed to the second reactor 103' such that the temperature of the reactants and products in contact with the catalyst is maintained at or Below 310°C to minimize the formation of undesirable by-products including methane, ethane, carbon dioxide and/or carbon monoxide. Additionally, above about 320°C, corrosion can become so severe that special and expensive alloy materials must be used. The temperature of the content in line 133 after cooling is preferably 200°C-300°C, for example 210°C-275°C or 220°C-260°C. Reactors 103 and 103' may be of the same size and configuration or they may be of different sizes and configurations. Each reactor preferably contains the same type of catalyst, although additional and/or different catalysts may be used for each reactor. As an example, the catalysts described above can be utilized. Additionally, catalysts, catalyst mixtures, mixtures with inert materials, and/or catalysts with different active metal concentrations may be utilized. For example, a catalyst may include metals of the same type in varying ratios. The crude ethanol product is preferably withdrawn continuously from reactor 103&apos; Thus, the heat from the caide ethanol product may be advantageously used to preheat the acetic acid feed prior to its introduction into the evaporator 110 . Conversely, the caide ethanol product may be cooled using the acetic acid feed as a cooling medium before it is introduced into the first flasher 106 . The vapor stream exiting the first flasher, comprising hydrogen and hydrocarbons, may be purged and/or returned to reaction zone 101 via line 113 . As shown in FIG. 2 , at least a portion of the recycle vapor stream is passed through compressor 114 and co-fed (or combined with hydrogen and then co-fed) with hydrogen to evaporator 110 .

The remaining liquid in flasher 106 is withdrawn via line 134 and fed to second flasher 106' to remove any residual vapor dissolved in the liquid. The second flasher 106 ′ may operate at a lower temperature and/or pressure than the first flasher 106 . In one embodiment, the temperature of the second flasher 106' is preferably 20°C-100°C, such as 30°C-85°C or 40°C _- 70°C. In one embodiment, the temperature of the second flasher 106' is preferably less than The first flasher 106 is at least 50°C lower, such as at least 75°C lower or at least 100°C lower. The pressure of the second flasher 106' is preferably 0.1KPa-1000KPa, such as 0.1KPa-500KPa or 0.1KPa-100KPa. In one embodiment, the pressure of the second flasher 106 ′ is preferably at least 50 KPa lower than that of the first flasher 106 , such as at least 100 KPa lower or at least 200 KPa lower. The vapor stream 135 exiting the second flasher may contain hydrogen and hydrocarbons, which may be purged and/or returned to the reaction zone in a similar manner to the first flasher 106 . As described, for example, with respect to Figure 1, the remaining liquid in flasher 106' is withdrawn and pumped via line 115 to the side of the first column (not shown in Figure 2) and further purified to form an ethanol product stream, namely " Finished Ethanol".

Finished Ethanol Composition

The finished ethanol composition obtained by the process of the invention preferably comprises ethanol, water and a minor amount of isopropanol. As indicated above, preferably the ethanol composition is predominantly ethanol, containing 92 wt.% to 96 wt.%, eg 93 wt.% to 96 wt.% or 95 wt.% to 96 wt.% ethanol. In addition, the amount of isopropanol in the ethanol composition is 95-1,000 wppm, such as 110-800 wppm or 110-400 wppm.

In another embodiment, the ethanol composition comprises less than 270 wppm, eg, less than 200 wppm total of n-propanol and isopropanol. In terms of ranges, the ethanol composition comprises 95 wppm to 270 wppm, eg, 100 wppm to 250 wppm or 120 wppm to 200 wppm total of n-propanol and isopropanol. In a preferred embodiment, the total amount of isopropanol and n-propanol in the ethanol composition is less than 1,000 wppm, typically such as less than 400 wppm or less than 200 wppm.

In another embodiment, the ethanol composition comprises ethanol, isopropanol, and low amounts of alcohols other than ethanol and isopropanol, such as methanol, n-propanol, and C4 ₊ alcohols. In one embodiment, the ethanol composition comprises less than 350 wppm, eg, less than 300 wppm or less than 275 wppm, alcohol other than ethanol and isopropanol. In terms of ranges, the composition may comprise an alcohol other than ethanol and isopropanol in an amount of 1 wppm to 350 wppm, for example 100 wppm to 325 wppm.

In addition, ethanol compositions may contain small amounts of various organic impurities. Examples of such impurities include acetaldehyde, acetic acid, diethyl acetal, ethyl acetate, n-propanol, methanol, butanol, 2-butanol, isobutanol, isoamyl alcohol, pentanol, benzene, and mixtures thereof. In preferred embodiments, the ethanol compositions of the present invention comprise low amounts of organic impurities, eg, less than 1 wt.%, less than 0.75 wt.%, or less than 0.5 wt.% organic impurities. In another embodiment, the ethanol compositions of the present invention comprise low, if any, amounts of _C5 alcohols. For example, the ethanol composition may comprise less than 0.005 wt.%, such as less than 0.001 wt.% or less than 0.0005 wt.% _C alcohols. In one embodiment, the ethanol composition comprises 50 wppm to 1 wt.%, such as 100 wppm to 1 wt.%, or 400 wppm to 1 wt.% branched chain alcohol. In one embodiment, the branched alcohols are branched alcohols other than isopropanol. Exemplary weight percentages for each component are given in Table 7.

In one embodiment, the ethanol composition may comprise acetone in an amount of less than 500 wppm, less than 100 wppm, or less than 50 wppm. In terms of ranges, the ethanol composition may comprise 10 wppm to 500 wppm acetone, eg, 30 wppm to 400 wppm acetone or 50 wppm to 300 wppm acetone. The ethanol composition of the present invention may comprise acetaldehyde in an amount of less than 18 wppm, less than 10 wppm, or less than 5 wppm.

In other embodiments, the ethanol composition comprises very low amounts of metals, if any, eg, the ethanol compositions of the present invention comprise substantially no metals. For example, in one embodiment, the ethanol composition of the present invention comprises less than 10 wppm copper, eg, less than 1 wppm, less than 0.1 wppm, or less than 0.05 wppm copper. In one embodiment, the ethanol composition is substantially free of copper, preferably the ethanol composition is copper free. In one embodiment, the ethanol composition of the present invention is substantially free of heavy metals.

In one embodiment, the ethanol composition contains very low amounts of inorganics. For example, the ethanol composition may comprise less than 20 mg/L, such as less than 10 mg/L, less than 8 mg/L, or less than 5 mg/L chlorine/chloride. In terms of parts per million, the ethanol composition may comprise less than 40 wppm chlorine/chloride, eg, less than 20 wppm or less than 10 wppm. In one embodiment, the ethanol composition contains substantially no chlorine, preferably the ethanol composition contains no chlorine.

In one embodiment, the ethanol composition comprises less than 50 wppm sulfur, eg, less than 30 wppm, less than 10 wppm, less than 7 wppm, less than 5 wppm, or less than 3 wppm. In one embodiment, the ethanol composition comprises substantially no sulfur, preferably the ethanol composition comprises no sulfur. In one embodiment, the ethanol composition may comprise less than 10 wppm, eg, less than 4 wppm, less than 3 wppm, less than 2 wppm, or less than 1 wppm sulfate. In one embodiment, the ethanol composition is substantially free of sulphate, preferably the ethanol composition is free of sulphate.

In one embodiment, the ethanol composition comprises less than 2 mg/L, such as less than 1 mg/L, less than 0.5 mg/L, less than 0.3 mg/L, less than 0.2 mg/L or less than 0.1 mg/L phosphorus. In one embodiment, the ethanol composition comprises substantially no phosphorus, preferably the ethanol composition comprises no phosphorus.

In one embodiment, the ethanol composition has a pHe of 6.0-9.5, such as 6.5-9.0. In one embodiment, the ethanol composition has a total acidity (calculated as acetic acid) of less than 0.01 wppm, such as less than 0.007 wppm. In one embodiment, the ethanol composition has a total acidity (calculated as acetic acid) of less than 65 mg/L, such as less than 56 mg/L or less than 30 mg/L.

In another embodiment, the ethanol composition comprises at least one in situ denaturant, eg, a denaturant co-produced with the ethanol. In these cases, the ethanol composition may be considered a "denatured ethanol composition". Preferably, the denatured ethanol composition does not contain denaturants not prepared in situ by hydrogenation reactions. In one embodiment, the denatured ethanol composition comprises substantially no ex situ denaturants. Because the denaturant is provided by the synthesis reaction, the denatured ethanol composition advantageously does not require an additional (external) denaturant to form the denatured ethanol composition upon synthesis. As a result, the denatured ethanol composition is suitable for commercial use when synthesized, eg, suitable for delivery as a denatured ethanol composition without other additions or treatments.

Any components, percentages or physical/chemical properties discussed herein apply to any contemplated ethanol composition embodied herein.

The finished ethanol compositions disclosed herein are suitable for use in a variety of applications, including fuels. In one embodiment, the ethanol composition can be present in the ethanol/fuel blend in an amount from about 2 vol.% to about 98 vol.%, and the fuel can be present in an amount from about 2 vol.% to about 98 vol.%. In another embodiment, the ethanol composition may be present in the ethanol/fuel blend in an amount from about 5 vol.% to about 95 vol.%, and the fuel may be present in an amount from about 5 vol.% to about 95 vol.%. In yet another embodiment, the ethanol composition can be present in the ethanol/fuel blend in an amount from about 10 vol.% to about 90 vol.%, and the fuel can be present in an amount from about 10 vol.% to about 90 vol.%. In yet another embodiment, the ethanol composition can be present in the ethanol/fuel blend in an amount from about 15 vol.% to about 85 vol.%, and the fuel can be present in an amount from about 15 vol.% to about 85 vol.%.

Fuels for the ethanol/fuel blends disclosed herein include, but are not limited to, gasoline, diesel fuel, ULSD, kerosene, jet fuel, biofuel blends, Fischer-Tropsch derived fuels, other fuels derived from petroleum or non-petroleum feedstocks, and their concoction.

In ethanol/fuel applications, the finished ethanol composition is blended with an acceptable denaturant to form a denatured fuel ethanol composition. The denatured fuel ethanol composition thus produced can then be blended with gasoline, for example at a terminal loading rack, for use in motor vehicles such as automobiles, boats and small piston engine aircraft. Permissible denaturants may be present in the denatured fuel ethanol composition in an amount of at least 1.96 vol.%. Permitted fuel denaturants include natural gasoline, gasoline blends, and unleaded gasoline.

In one embodiment, the ethanol/fuel blend includes one or more compounds selected from the group consisting of oxygenates, detergents, dispersants, lubricants, cetane number improvers, cold flow improvers, metal deactivators, Fuel additives for emulsions, defoamers, dyes, corrosion inhibitors and their blends.

As discussed above, the ethanol composition of the present invention may be a component of a fuel composition. In one embodiment, a fuel composition may comprise a fuel component and an ethanol composition of the present invention, which may comprise isopropanol in the amounts discussed herein, such as isopropanol formed in situ. In these cases, the denaturant is formed from the reactions that form the ethanol composition. In some embodiments, the fuel composition includes alcohol that is formed ex situ, eg, by adding an exogenous alcohol to the fuel composition. In one embodiment, the fuel composition comprises both in situ formed isopropanol and ex situ formed isopropanol, eg, exotic isopropanol. Conventional ethanol compositions do not contain in situ formed isopropanol in the amounts disclosed herein.

In one embodiment, the fuel comprises gasoline present in an amount of about 90 vol.%, or 85 vol.%, or 15 vol.%.

In one embodiment, the fuel comprises diesel fuel, which may be present in an amount of about 95 vol.%, or 90 vol.%, or 85 vol.%.

In the United States, to comply with current regulations, finished ethanol compositions are blended with at least 1.96 vol.% of allowed denaturants. The maximum acceptable amount of fuel denaturant is currently 5 vol.%. As indicated above, allowed denaturants per ASTM D4806 are limited to natural gasoline, gasoline blending stock, and unleaded gasoline. Suitable blend stocks include, but are not limited to, alkylate streams, catalytically cracked gasoline streams (such as cracked naphtha); aromatic saturated gasoline streams, light straight-run gasoline streams, heavy straight-run gasoline streams, degassed Hexanizer bottoms stream, dehexanizer overhead stream, hydrocracker topped light naphtha, reformate, toluene and butane streams.

Production of absolute ethanol

Reference is now made to Figures 4A and 4B. If it should be required to meet performance specifications, such as those of ASTM 4806-11, or other local requirements, the third distillate in line 119 can be further treated to substantially remove water therefrom. This further processing results in the formation of an anhydrous ethanol product stream, such as an anhydrous ethanol composition. In one embodiment, this further processing uses one or more separation units, such as dehydrators. Examples of suitable dehydrators include extractive distillation column 122 (shown in Figure 4A); molecular sieve unit 124 (shown in Figure 4B); and/or desiccant (not shown). For example, useful dehydration methods and/or units include those discussed in US Patent Nos. 4,465,875; 4,559,109; 4,654,123; and 6,375,807. These patents are hereby incorporated by reference in their entirety.

Typically, the water and ethanol in the third distillate form a water/ethanol azeotrope. In one embodiment, the dehydrator of the present invention removes water from the water/ethanol azeotrope in the third distillate. For example, dehydration can remove at least 50 wt.%, such as at least 75 wt.%, at least 90 wt.%, at least 95 wt.%, or at least 99 wt.% of water from the third distillate. In terms of range, dehydration removes 50wt.%-100wt.% from the third distillate, such as 75wt.%-99.9999wt.%, 90wt.%-99.999wt.%, 90wt.%-99.99wt.%, 90wt.%-99.9wt.% or 90wt.%-99.5wt.% of water. Removal of this water from the third distillate results in the formation of an anhydrous ethanol composition.

Aqueous stream 128 leaving the dehydrator comprises primarily water, such as at least 50 wt.%, such as at least 75 wt.%, at least 90 wt.%, at least 95 wt.%, or at least 99 wt.% water, and is preferably removed from system 100. remove. In one embodiment, the fourth residue 128 portion may be returned to any part of the system 100 . In a preferred embodiment, water may be used as the extractant in any of the columns, such as the second column 108 .

In FIG. 4A , the distillate from third column 109 comprising the ethanol/water azeotrope can be fed, for example, via line 119 , to fourth column 122 (also referred to as the "finishing column"). Fourth column 122 further separates, eg distills, water from the water/ethanol azeotrope in the third distillate. As a result, fourth column 122 recovers ethanol that has been further dehydrated as a fourth distillate in line 126 .

Preferably, fourth column 122 is an extractive distillation column using an extractant and preferably operating at atmospheric pressure. Extractive distillation is a gas-liquid separation process that uses additional components to increase the relative volatility of the components to be separated. In extractive distillation, selective high boiling point solvents are used to alter the activity coefficient and thus increase the separation factor of the components. Additional components may be liquid solvents, ionic liquids, dissolved salts, mixtures of volatile liquid solvents and dissolved salts, or hyperbranched polymers.

The fourth column 122 preferably comprises 1-150 trays, such as 10-100 or 20-70 trays. As indicated above, the trays may be sieve trays, fixed valve trays, moving valve trays, or any other suitable design known in the art. Exemplary extractants may include, but are not limited to, ethylene glycol, glycerin, gasoline, and hexane. The third distillate in line 119 can be introduced to fourth column 122 at any level. Preferably, line 119 is introduced into fourth column 122 in a middle portion of fourth column 122 , such as the middle half or middle third.

In one embodiment, as shown in Figure 4B, the distillate from the third column 109 is fed to a molecular sieve unit 124 comprising molecular sieves. In these embodiments, molecular sieves separate additional water from the third distillate in line 119. In some embodiments, molecular sieve unit 124 may be used in place of or in conjunction with a finishing column. Generally, the molecular sieves can be disposed in a molecular sieve bed (not shown). In one embodiment, the molecular sieve is selected to remove one or more impurities that may be present in the third distillate. Selection criteria may include, for example, pore size and volumetric properties. In one embodiment, the molecular sieve material is selected to remove water, acetic acid, and/or ethyl acetate from the third distillate to form an anhydrous ethanol composition. Suitable molecular sieves include, for example, zeolites and molecular sieves 3A, 4A and 5A (commercially available from Aldrich). In another embodiment, inorganic sorbents such as lithium chloride, silica gel, activated alumina, and/or biobased sorbents such as corn grit can be used. In a preferred embodiment, molecular sieve unit 124 removes water in the amounts described above from the third distillate.

In addition, other separation units, such as dehydration units such as desiccant systems and/or membrane systems, can be used instead of or in combination with the above-mentioned refining tower and/or molecular sieve unit. If multiple dewatering units are used, the same or different types of dewatering units may be used in any configuration. Preferably, extractive distillation columns and membrane systems are used together with each other. Optionally, molecular sieves are used in the refining column, for example as a bed in the upper part thereof.

Other exemplary dehydration methods include azeotropic distillation and membrane separation. In azeotropic distillation, a volatile component, often called an entrainer, is added to the components to be separated. The addition of an entrainer forms an azeotrope with the components, thus changing their relative volatility. As a result, the separation factor (activity coefficient) of the components is improved. In one embodiment, the azeotropic distillation system comprises one or more distillation columns, such as two or more or three or more distillation columns.

Membrane separations such as membrane pervaporation can also be an efficient and energy efficient method for separating azeotropic mixtures. In general, pervaporation is based on a solution diffusion mechanism that relies on a gradient in chemical potential between the feed and the permeate side of the membrane. In one embodiment, the membrane can be hydrophilic or hydrophobic. Preferably, the membrane is hydrophilic or water permselective due to the smaller molecular size of water. In other embodiments, the membrane is hydrophobic or selectively permeable to ethanol. Typically, three types of membranes can be used, namely inorganic membranes, polymer membranes and composite membranes.

Absolute ethanol composition

The absolute ethanol composition advantageously comprises ethanol preferably formed by the acetic acid hydrogenation and separation steps of the present invention and, if any, a small amount of water. In one embodiment, the term "absolute ethanol composition" as used herein refers to a substantially anhydrous ethanol composition. For example, the substantially anhydrous ethanol composition may have less than 1 wt.%, such as less than 0.5 wt.%, less than 0.1 wt.%, less than 0.01 wt.%, less than 0.001 wt.%, based on the total weight of the substantially anhydrous ethanol composition. Water content of wt.% or less than 0.0001 wt.% water. Table 8 provides exemplary ranges for water concentrations in absolute ethanol compositions. Anhydrous ethanol compositions can be completely anhydrous, eg, contain no detectable water, although Table 8 shows that in other embodiments water is preferably present in small amounts. In these cases, the water content or absence can be measured using conventional water detection methods used in the industry. Preferably, the absolute ethanol composition comprises at least 95 wt.%, such as at least 95 wt.%, at least 99 wt.%, at least 99.9 wt.% or at least 99.99 wt.% ethanol. Table 6 provides exemplary ranges of ethanol concentrations in absolute ethanol compositions.

In addition to ethanol and, if any, small amounts of water, absolute ethanol compositions may also contain only trace amounts of other impurities such as acetic acid; _C3 alcohols such as n-propanol; and/or _C4 - _C5 alcohols. Exemplary compositional ranges for ethanol, water, and various impurities that may be present in minor, if any, amounts are provided in Table 8 below.

In other embodiments, the ethanol composition comprises very low amounts of metals, if any, eg, the ethanol compositions of the present invention comprise substantially no metals. For example, in one embodiment, the ethanol composition of the present invention comprises less than 10 wppm copper, eg, less than 1 wppm, less than 0.1 wppm, or less than 0.05 wppm copper. In one embodiment, the ethanol composition of the present invention is substantially free of heavy metals.

In one embodiment, the ethanol composition contains very low amounts of inorganics. For example, the ethanol composition may comprise less than 10 mg/L, such as less than 8 mg/L or less than 5 mg/L chlorine/chloride. In terms of parts per million, the ethanol composition may comprise less than 40 wppm chlorine/chloride, eg, less than 20 wppm or less than 10 wppm. In one embodiment, the ethanol composition comprises less than 30 wppm sulfur, eg, less than 10 wppm, less than 7 wppm, less than 5 wppm, or less than 3 wppm. For example, the ethanol composition may comprise less than 4 wppm, such as less than 3 wppm, less than 2 wppm, or less than 1 wppm sulfate. In one embodiment, the ethanol composition comprises less than 0.5 mg/L, such as less than 0.3 mg/L, less than 0.2 mg/L or less than 0.1 mg/L phosphorus.

The anhydrous ethanol compositions of the present invention preferably contain very low amounts, eg, less than 0.5 wt.%, of other alcohols, such as methanol, butanol, isobutanol, isoamyl alcohol, and other _C4 - _C20 alcohols.

The anhydrous ethanol compositions disclosed herein are suitable for use in various applications including fuels. In one embodiment, the ethanol composition can be present in the ethanol/fuel blend in an amount from about 2 vol.% to about 98 vol.%, and the fuel can be present in an amount from about 2 vol.% to about 98 vol.%. In another embodiment, the ethanol composition may be present in the ethanol/fuel blend in an amount from about 5 vol.% to about 95 vol.%, and the fuel may be present in an amount from about 5 vol.% to about 95 vol.%. In yet another embodiment, the ethanol composition can be present in the ethanol/fuel blend in an amount from about 10 vol.% to about 90 vol.%, and the fuel can be present in an amount from about 10 vol.% to about 90 vol.%. In yet another embodiment, the ethanol composition can be present in the ethanol/fuel blend in an amount from about 15 vol.% to about 85 vol.%, and the fuel can be present in an amount from about 15 vol.% to about 85 vol.%.

Fuels for the ethanol/fuel blends disclosed herein include, but are not limited to, gasoline, diesel fuel, ULSD, kerosene, jet fuel, biofuel blends, Fischer-Tropsch derived fuels, other fuels derived from petroleum or non-petroleum feedstocks, and their concoction.

In ethanol/gasoline applications, the absolute ethanol composition is blended with an acceptable denaturant to form a denatured fuel ethanol composition. The denatured fuel ethanol composition thus produced can then be blended with gasoline fuel, for example at a terminal loading rack, for use in motor vehicles such as automobiles, boats and small piston engine aircraft. Permissible denaturants may be present in the denatured fuel ethanol composition in an amount of at least 1.96 vol.%. Permitted fuel denaturants include natural gasoline, gasoline blends, and unleaded gasoline.

In one embodiment, the ethanol/fuel blend includes one or more compounds selected from the group consisting of oxygenates, detergents, dispersants, lubricants, cetane number improvers, cold flow improvers, metal deactivators, Fuel additives for emulsions, defoamers, dyes, corrosion inhibitors and their blends.

In one embodiment, the fuel comprises gasoline present in an amount of about 90 vol.%, or 85 vol.%, or 15 vol.%.

In one embodiment, the fuel comprises diesel fuel, which may be present in an amount of about 95 vol.%, or 90 vol.%, or 85 vol.%.

In the United States, to comply with current regulations, anhydrous ethanol compositions are blended with at least 1.96 vol.% of allowed denaturants. The maximum conforming amount of allowed fuel denaturant is currently 5 vol.%. As indicated above, allowed denaturants per ASTM D4806 are limited to natural gasoline, gasoline blending stock, and unleaded gasoline. Suitable blend stocks include, but are not limited to, alkylate streams, catalytically cracked gasoline streams (such as cracked naphtha); aromatic saturated gasoline streams, light straight-run gasoline streams, heavy straight-run gasoline streams, degassed Hexanizer bottoms stream, dehexanizer overhead stream, hydrocracker topped light naphtha, reformate, toluene and butane streams.

In one embodiment, the fuel blended ethanol composition contains very low amounts of metals, if any, eg, the fuel blended ethanol composition contains substantially no metals. In another embodiment, the fuel blended ethanol composition contains substantially no heavy metals. For example, in one embodiment, the fuel blend ethanol composition is substantially lead-free, comprising less than 20 mg/1, such as less than 15 mg/1, less than 10 mg/1, or less than 5 mg/1 lead. In one embodiment, the fuel blend ethanol composition is substantially free of manganese. For example, the fuel blend ethanol composition comprises less than 10 mg/1 manganese, such as less than 6 mg/1, less than 3 mg/1, less than 1 mg/1 manganese. In one embodiment, the fuel blend ethanol composition is substantially free of copper. For example, the fuel blend ethanol composition comprises less than 0.5 mg/kg copper, or less than 0.3 mg/kg copper, or less than 0.1 mg/kg copper. In one embodiment, the fuel blend ethanol composition is substantially free of sodium and potassium combinations. For example, the fuel blended ethanol composition comprises less than 10 mg/kg, such as less than 8 mg/kg, less than 5 mg/kg, or less than 2 mg/kg of sodium and potassium combined. In one embodiment, the fuel blend ethanol composition is substantially free of calcium and magnesium in combination. For example, the fuel blend ethanol composition comprises less than 15 mg/kg, such as less than 10 mg/kg, less than 5 mg/kg, or less than 2 mg/kg of calcium and magnesium combined. In another embodiment, the fuel blended ethanol composition is substantially free of aluminum and silicon. For example, the fuel blended ethanol composition comprises less than 60 mg/kg, such as less than 50 mg/kg, less than 25 mg/kg, less than 10 mg/kg, or less than 5 mg/kg of aluminum and silicon combined. In another embodiment, the fuel blended ethanol composition is substantially free of sodium. For example, the fuel blended ethanol composition comprises less than 150 mg/kg, such as less than 100 mg/kg, less than 50 mg/kg, or less than 10 mg/kg of sodium. In one embodiment, the fuel blended ethanol composition is substantially free of vanadium. For example, the fuel-blend ethanol composition comprises less than 400 mg/kg, such as less than 350 mg/kg, less than 200 mg/kg, or less than 150 mg/kg of vanadium. In another embodiment, the fuel blended ethanol composition is substantially free of calcium. For example, the fuel blend ethanol composition comprises less than 50 mg/kg, such as less than 30 mg/kg, less than 15 mg/kg or less than 10 mg/kg calcium. In another embodiment, the fuel blended ethanol composition is substantially free of zinc. For example, the fuel blend ethanol composition comprises less than 25 mg/kg zinc, such as less than 15 mg/kg zinc, or less than 10 mg/kg zinc.

The denatured fuel ethanol compositions used in the ethanol/fuel blends disclosed herein are capable of meeting standard specifications for denatured fuel ethanol.

In order that the invention disclosed herein may be more effectively understood, the following non-limiting examples are provided. The following examples describe various embodiments of the ethanol compositions of the present invention.

Example

Example 1

Using the hydrogenation method and separation method described above, several ethanol compositions were prepared. At an average temperature of 291 °C and an outlet pressure of 2,063 KPa, a gasification feed containing 95.2 wt.% acetic acid and 4.6 wt.% water was reacted with hydrogen in the presence of a catalyst to produce The crude ethanol product of esters, the catalyst comprising 1.6 wt.% platinum and 1 wt.% tin supported on a 1/8 foot calcium silicate modified silica extrudate. Recycling of unreacted hydrogen back to the reactor inlet resulted in an overall H ₂ /acetic acid molar ratio of 5.8 at a GHSV of 3,893 hr ⁻¹ . The crude ethanol product was purified using a separation scheme with a distillation column as shown in Figure 1 .

Table 10 shows the compositional data for these ethanol compositions. The term "C2 ₊ alcohol" as used herein relates to alcohols having more than 2 carbon atoms

Comparative example A

Table 11 shows data for comparative ethanol compositions produced by fermentation of sugarcane.

Comparative Example B

Table 12 shows data for comparative ethanol compositions prepared by fermentation of molasses.

Comparative Example C

Table 13 shows data for comparative ethanol compositions prepared by Fischer-Tropsch synthesis.

Surprisingly and unexpectedly, the amount of isopropanol is higher in Example 1 than in Comparative Examples A-C. Furthermore, the amount of methanol in Example 1 is advantageously undetectable. In contrast, the amount of methanol in Comparative Examples A-C was significantly higher, eg, 42 wppm-51 wppm.

Example 2

A sample of the crude ethanol product was prepared by hydrogenation of acetic acid as discussed above. The sample contained ethanol, acetic acid, acetaldehyde, water and ethyl acetate.

Each crude ethanol product sample was purified using the first column, second column, and third column as shown in Figure 1A. In each case, analysis was performed on the third distillate obtained from the respective crude ethanol product samples. In Table 14 the average composition values for the third distillate are provided.

The third distillate, when dehydrated as discussed above, provided an anhydrous ethanol composition having the average composition values provided in Table 15. As shown in Table 15, anhydrous ethanol compositions that may be formed by the acetic acid hydrogenation and separation steps of the present invention comprise ethanol and, if present, a small amount of water.

Having described the invention in detail, various modifications within the spirit and scope of the invention will become apparent to those skilled in the art. In view of the foregoing discussion, the relevant knowledge in the art and references discussed above in relation to the Background and Detailed Description, the disclosures of which are hereby incorporated by reference in their entireties. Furthermore, it is to be understood that aspects of the invention, as well as various embodiments and portions of features recited below and/or in the appended claims may be combined or interchanged in part or in whole. In the foregoing descriptions of the respective embodiments, those embodiments referring to another embodiment may be appropriately combined with other embodiments as would be recognized by those skilled in the art. Furthermore, those skilled in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.

Claims (92)

1. ethanol/fuel mediation composition, the method preparation of described mediation composition by comprising the following steps:

Make acetic acid feed hydrogenation to form the crude ethanol product comprising ethanol, Virahol and one or more organic impuritys in the presence of a catalyst;

Be separated to small part crude ethanol product with the ethanol composition removing one or more impurity and reclaim containing at least 92wt.% ethanol, 95wppm-850wppm Virahol and n-propyl alcohol, wherein the weight ratio of Virahol and n-propyl alcohol is at least 0.5:1; And

Ethanol composition and fuel are in harmonious proportion and are in harmonious proportion composition to form ethanol/fuel.

2. the composition of claim 1, wherein said ethanol composition is present in ethanol/fuel with the amount of 2vol.%-98vol.% and is in harmonious proportion in composition and described fuel exists with the amount of 2vol.%-98vol.%.

3. the composition of claim 2, wherein said fuel is selected from gasoline, diesel oil fuel, ULSD, kerosene, rocket engine fuel, biofuel temper, fischer-tropsch derived fuel, derived from other fuel and their temper of oil or non-petroleum feedstocks.

4. the composition of claim 3, wherein said fuel package is containing gasoline.

5. the composition of claim 4, wherein said ethanol composition also comprises the fuel denaturing agent of at least 1.96vol.%.

6. the composition of claim 5, wherein said fuel denaturing agent is selected from natural gasoline, gasoline blending stock and white gasoline.

7. the composition of claim 6, wherein said gasoline exists with the amount of 90vol.%.

8. the composition of claim 6, wherein said gasoline exists with the amount of 85vol.%.

9. the composition of claim 6, wherein said gasoline exists with the amount of 15vol.%.

10. the composition of claim 1, described composition also comprises the fuel dope that one or more are selected from oxygenatedchemicals, purification agent, dispersion agent, lubricant, cetane number improver, cold flow improver, metal passivator, emulsion splitter, defoamer, dyestuff, corrosion inhibitor and their temper.

The composition of 11. claims 1, wherein said fuel package is containing diesel oil fuel.

The composition of 12. claims 11, wherein said diesel oil fuel exists with the amount of 90vol.%.

The composition of 13. claims 1, wherein said ethanol composition also comprises the organic impurity that one or more are selected from acetaldehyde, acetic acid, diethyl acetal, ethyl acetate, n-propyl alcohol, butanols, 2-butanols, isopropylcarbinol and their mixture.

The composition of 14. claims 13, wherein said ethanol composition comprises one or more organic impuritys being less than 1wt.%.

The composition of 15. claims 1, wherein said ethanol composition also comprises the acetaldehyde being less than 18wppm.

The composition of 16. claims 1, wherein said ethanol composition also comprises the diethyl acetal being less than 10wppm.

The composition of 17. claims 1, wherein said ethanol composition also comprises the C being less than 300wppm ₄-C ₅alcohol.

The composition of 18. claims 1, wherein said ethanol composition also comprises the n-propyl alcohol of 95wppm-270wppm.

The composition of 19. claims 1, wherein said ethanol composition is not obtained by fermentation.

The composition of 20. claims 1, wherein said ethanol composition does not comprise methyl alcohol substantially.

The composition of 21. claims 1, wherein said ethanol composition does not comprise methyl alcohol.

The composition of 22. claims 1, wherein said ethanol composition does not comprise chlorine substantially.

The composition of 23. claims 1, wherein said ethanol composition does not comprise chlorine.

The composition of 24. claims 1, wherein said ethanol composition comprises the chlorine being less than 40wppm.

The composition of 25. claims 1, wherein said ethanol composition does not comprise copper substantially.

The composition of 26. claims 1, wherein said ethanol composition does not comprise copper.

The composition of 27. claims 1, wherein said ethanol composition comprises the copper being less than 10wppm.

The composition of 28. claims 1, wherein said ethanol composition does not comprise sulphur substantially.

The composition of 29. claims 1, wherein said ethanol composition does not comprise sulphur.

The composition of 30. claims 1, wherein said ethanol composition comprises the sulphur being less than 50wppm.

The composition of 31. claims 1, wherein said ethanol composition does not comprise vitriol substantially.

The composition of 32. claims 1, wherein said ethanol composition does not comprise vitriol.

The composition of 33. claims 1, wherein said ethanol composition comprises the vitriol being less than 10wppm.

The composition of 34. claims 1, wherein said ethanol composition does not comprise phosphorus substantially.

The composition of 35. claims 1, wherein said ethanol composition does not comprise phosphorus.

The composition of 36. claims 1, wherein said ethanol composition comprises the phosphorus being less than 2 mg/litre.

The composition of 37. claims 1, wherein said ethanol composition has the pHe of 6-9.5.

The composition of 38. claims 1, wherein said ethanol composition has the total acidity being less than 0.01wppm with acetometer.

The composition of 39. claims 1, wherein said ethanol composition comprises the branched-chain alcoho of 50wppm-1wt.%.

The composition of 40. claims 1, wherein said ethanol composition comprises the alcohol except ethanol being less than 350wppm.

The composition of 41. claims 1, described composition also comprises the C being less than 22wppm ₄-C ₅alcohol.

The composition of 42. claims 1, wherein said ethanol composition is substantially free of C ₆₊alcohol.

The composition of 43. claims 1, wherein said ethanol composition is derived from acetic acid hydrogenation.

The composition of 44. claims 43, wherein said Virahol is that original position is formed.

The composition of 45. claims 43, wherein said acetic acid is formed by methyl alcohol and carbon monoxide, wherein methyl alcohol, carbon monoxide and for the hydrogen of hydrogenation step separately derived from synthetic gas, and the wherein said syngas-derived carbon source from being selected from Sweet natural gas, oil, oil, coal, biomass and their combination.

The composition of 46. claims 1, wherein said composition is substantially free of lead.

The composition of 47. claims 1, described composition also comprises the lead being less than 15mg/l.

The composition of 48. claims 1, described composition also comprises the lead being less than 5mg/l.

The composition of 49. claims 1, described composition also comprises the manganese being less than 10mg/l.

The composition of 50. claims 1, described composition also comprises the manganese being less than 1mg/l.

The composition of 51. claims 1, wherein said composition is substantially free of heavy metal.

The composition of 52. claims 1, described composition also comprises the copper being less than 0.5mg/kg.

The composition of 53. claims 1, described composition also comprises the copper being less than 0.1mg/kg.

The composition of 54. claims 1, described composition also comprises and is less than the sodium of 8mg/kg and the combination of potassium.

The composition of 55. claims 1, described composition also comprises and is less than the sodium of 5mg/kg and the combination of potassium.

The composition of 56. claims 1, described composition also comprises and is less than the calcium of 10mg/kg and the combination of magnesium.

The composition of 57. claims 1, described composition also comprises and is less than the calcium of 5mg/kg and the combination of magnesium.

The composition of 58. claims 1, described composition also comprises and is less than the aluminium of 60mg/kg and the combination of silicon.

The composition of 59. claims 1, described composition also comprises and is less than the aluminium of 25mg/kg and the combination of silicon.

The composition of 60. claims 1, described composition also comprises the sodium being less than 150mg/kg.

The composition of 61. claims 1, described composition also comprises the sodium being less than 100mg/kg.

The composition of 62. claims 1, described composition also comprises the vanadium being less than 400mg/kg.

The composition of 63. claims 1, described composition also comprises the vanadium being less than 350mg/kg.

The composition of 64. claims 1, described composition also comprises the calcium being less than 50mg/kg.

The composition of 65. claims 1, described composition also comprises the calcium being less than 30mg/kg.

The composition of 66. claims 1, described composition also comprises the zinc being less than 25mg/kg.

The composition of 67. claims 1, described composition also comprises the zinc being less than 15mg/kg.

The composition of 68. claims 1, wherein ethanol/fuel mediation composition comprises:

Containing at least 95wt.% ethanol, 95wppm-850wppm Virahol, n-propyl alcohol, and the ethanol composition of at least 1.96vol.% fuel denaturing agent; And

White gasoline.

The composition of 69. claims 68, wherein said fuel denaturing agent is selected from natural gasoline, gasoline blending stock and white gasoline.

The composition of 70. claims 68, wherein said gasoline exists with the amount of 90vol.%.

The composition of 71. claims 68, wherein said gasoline exists with the amount of 85vol.%.

The composition of 72. claims 68, wherein said gasoline exists with the amount of 15vol.%.

The composition of 73. claims 68, described composition also comprises the fuel dope that one or more are selected from oxygenatedchemicals, purification agent, dispersion agent, metal passivator, emulsion splitter, defoamer, dyestuff, corrosion inhibitor and their temper.

The composition of 74. claims 68, the Virahol existed in wherein said ethanol composition and the weight ratio of n-propyl alcohol are at least 1:1.

The composition of 75. claims 68, the amount of the Virahol existed in wherein said ethanol composition is less than 850wppm.

The composition of 76. claims 68, the amount of the n-propyl alcohol existed in wherein said ethanol composition is less than 270wppm.

The composition of 77. claims 68, described composition also comprises the water being less than 1vol.%.

The composition of 78. claims 68, wherein said ethanol composition is derived from acetic acid hydrogenation.

The composition of 79. claims 68, wherein said Virahol is that original position is formed.

The composition of 80. claims 1, wherein ethanol/fuel mediation composition comprises:

Comprise at least 95wt.% ethanol, 95wppm-850wppm Virahol, n-propyl alcohol, and the ethanol composition of at least 1.96vol.% fuel denaturing agent; And

Ultra low sulfur diesel fuel.

The composition of 81. claims 80, wherein said fuel denaturing agent is selected from natural gasoline, gasoline blending stock and white gasoline.

The composition of 82. claims 80, wherein said ultra low sulfur diesel fuel exists with the amount of 95vol.%.

The composition of 83. claims 80, wherein said ultra low sulfur diesel fuel exists with the amount of 90vol.%.

The composition of 84. claims 80, wherein said ultra low sulfur diesel fuel exists with the amount of 85vol.%.

The composition of 85. claims 80, wherein said ethanol composition does not comprise sulphur substantially.

The composition of 86. claims 80, wherein said ethanol composition does not comprise sulphur.

The composition of 87. claims 80, wherein said ethanol composition comprises the sulphur being less than 30wppm.

The composition of 88. claims 80, wherein said ethanol composition is derived from acetic acid hydrogenation.

The composition of 89. claims 80, wherein said Virahol is that original position is formed.

90. 1 kinds of ethanol/fuel mediation compositions, described mediation composition comprises:

Contain the ethanol composition of at least 85wt.% ethanol, 50wppm-500wppm acetone, 95wppm-850wppm Virahol and n-propyl alcohol; With

White gasoline;

Wherein the weight ratio of Virahol and n-propyl alcohol is at least 0.5:1.

91. 1 kinds of ethanol/fuel mediation compositions, described mediation composition comprises:

Containing at least 85wt.% ethanol, the C being less than 10wppm ₆₊alcohol, the acetaldehyde being altogether less than 29wppm and C ₅the ethanol composition of alcohol, 95wppm-850wppm Virahol and n-propyl alcohol; And

White gasoline;

Wherein the weight ratio of Virahol and n-propyl alcohol is at least 0.5:1.

92. 1 kinds of ethanol/fuel mediation compositions, this mediation composition comprises:

Contain at least 85wt.% ethanol, the acetaldehyde being altogether less than 9wppm and C ₅the ethanol composition of alcohol, 95wppm-850wppm Virahol and n-propyl alcohol; And

White gasoline;

Wherein the weight ratio of Virahol and n-propyl alcohol is at least 0.5:1.