KR20120130765A - Processes for producing denatured ethanol - Google Patents

Abstract

The present invention relates to a process for the hydrogenation of an acetic acid feed in the presence of a catalyst to produce a crude ethanol product comprising ethanol and at least one denaturant and to separate the crude ethanol product from the at least one separation unit device into a denatured ethanol composition and at least one derivative stream It relates to a method for producing a modified ethanol composition comprising. The modified ethanol composition comprises 0.01 to 40% by weight of the modifier based on the total weight of the modified ethanol composition.

Description

Production method of modified ethanol {PROCESSES FOR PRODUCING DENATURED ETHANOL}

The present invention generally relates to a process for preparing a modified ethanol composition, specifically to a process for preparing a modified ethanol composition through hydrogenation of acetic acid to produce a crude ethanol product and a modifier.

Priority claim

This application is directed to US Patent Provisional Application No. 61 / 300,815, filed February 2, 2010, US Patent Provisional Application No. 61 / 332,727, filed May 7, 2010, and US Patent Provisional Application, filed May 7, 2010. Priority is claimed to US 61 / 332,696, and US patent application Ser. No. 12 / 889,260, filed Sep. 23, 2010, which is incorporated herein by reference.

Ethanol is often prepared for a variety of consumer products, such as beer, wine and spirits, and is used as a component of these products. Typically, ethanol for this use is prepared through fermentation. Many government departments impose high tariffs or taxes on consumer ethanol, thereby raising consumer prices.

However, there are many other uses of ethanol not related to consumption, such as fuels, chemical solvents or medicaments. In an effort to provide inexpensive ethanol for non-consumable applications, the duties or taxes levied on consumable ethanol are typically not required for non-consumable ethanol. In order to ensure that these ethanol compositions are used for non-consumable applications, most countries have laws and regulations requiring these ethanol compositions to include denaturants, which are substantially inadequate for drinking ethanol. It is added to pure ethanol composition. Thus, ethanol compositions that contain a denaturant and are not for consumption are often referred to as "modified ethanol" or "modified alcohol". Typical denaturing agents include methanol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, methyl isobutyl ketone and acetaldehyde.

The processing step of adding a denaturant to the drinkable ethanol composition adds complexity and cost to conventional methods of making modified ethanol. Therefore, there is a need for new and improved methods of producing modified ethanol.

In a first embodiment, the present invention provides hydrogenation of acetic acid in the presence of a catalyst to form a crude ethanol product comprising ethanol and one or more modifiers; A process for preparing a modified ethanol composition comprising separating the crude ethanol product into a modified ethanol composition and one or more derivative streams in one or more separation units, wherein the modified ethanol composition as prepared is 0.01 to 40 wt% denaturant, based on total weight.

In a second embodiment, the present invention provides hydrogenation of acetic acid in the presence of a catalyst to form a crude ethanol product comprising ethanol and a modifier; Separating the crude ethanol product into one or more derivative streams comprising an ethanol stream and separated denaturant; Further purification of the ethanol stream to form a purified ethanol stream; At least a portion of the isolated denaturant is combined with a purified ethanol stream to produce a modified ethanol composition.

The invention is described in detail below with reference to the accompanying drawings in which like numerals refer to like parts.
1A is a schematic diagram of a hydrogenation system according to one embodiment of the present invention.
FIG. 1B is a schematic diagram of the system shown in FIG. 1A returning the distillate of the second column to the reactor zone. FIG.
1C is a schematic diagram of a hydrogenation system according to one embodiment of the present invention.
2 is a graph showing the composition of an exemplary second residue stream at various tray locations in a third column.

Conventional methods for producing denatured ethanol begin with the production of purified ethanol. In these methods, ethanol can be produced and purified by conventional methods. Subsequently, the modified ethanol is added to purified ethanol to produce modified ethanol.

The present invention relates to a method for preparing the modified ethanol composition. In one embodiment, the present invention is directed to a method comprising hydrogenating acetic acid to form a crude ethanol product, for example in the presence of a catalyst. The crude ethanol product comprises one or more, for example two or three or more modifier (s). In one embodiment, the denaturant (s) can be prepared with ethanol. In other embodiments, the denaturant (s) are prepared as byproducts of the hydrogenation reaction. In other words, the denaturant is produced in situ with ethanol. The method of the invention further comprises in one embodiment separating the crude ethanol product into a modified ethanol composition and one or more derivative streams. The separation may be carried out in one or more, such as two or more or three or more separation units, for example in a distillation column. The resulting modified ethanol composition is derived from acetic acid and is 0.01 to 40% by weight, for example 0.01 to 25%, 0.01 to 20% by weight, based on the total weight of the modified ethanol composition or 1 wt% to 15 wt% denaturant, and 50 wt% to 99 wt%, such as 60 wt% to 99 wt% or 70 wt% to 95 wt% ethanol. Thus, by forming the denaturant in situ with ethanol in the hydrogenation step, the process of the present invention can produce more modified ethanol more efficiently and reduce the processing step. In particular, the process of the present invention may eliminate the need to separately produce or obtain the denaturant and then add the denaturant to ethanol.

In another embodiment, the invention relates to a process for the preparation of a modified ethanol composition which forms a denaturant from the hydrogenation of acetone, wherein acetone can be added to the reaction zone or produced as an intermediate in situ as a by-product from hydrogenation of acetic acid. Can be. In one embodiment, for example, the method comprises contacting acetic acid with acetone to produce an acetic acid reaction mixture. The method further comprises hydrogenating the acetic acid reaction mixture in the presence of a catalyst to produce a crude ethanol product comprising ethanol and isopropanol. In one embodiment, acetone is prepared in a supplemental acetone reactor or obtained from an external source. After being prepared or obtained, acetone can be contacted with acetic acid as discussed above. In another embodiment, the catalyst or reaction conditions used in the hydrogenation reaction are selected such that acetone is produced as a byproduct of the acetic acid hydrogenation reaction. After preparation, the acetone intermediate may be hydrogenated to produce isopropanol modifiers. In these embodiments, ethanol is produced with isopropanol modifier. Preferably, ethanol and isopropanol are produced in the same reactor. The method of the invention further comprises in one embodiment separating the crude ethanol product into a modified ethanol composition and one or more derivative streams. The resulting modified ethanol composition is 0.01 to 10% by weight, for example 0.01 to 5% by weight, or 0.01 to 3% by weight of isopropanol modifier based on the total weight of the modified ethanol composition in the state formed And 50% to 99% by weight, such as 60% to 99% or 70% to 95% by weight of ethanol.

The hydrogenation of acetic acid to produce ethanol and water can be represented by the following reaction:

Suitable hydrogenation catalysts optionally include a catalyst comprising a first metal and optionally one or more second metals, third metals or additional metals on the catalyst support. The first metal and optional second and third metals are any of IB, IIB, IIIB, IVB, VB, VIB, VIIB, Group VIII transition metals, lanthanide metals, actinium metals or any of IIIA, IVA, VA and VIA groups. And metal selected from the group. Preferred metal combinations for some exemplary catalyst compositions include platinum / tin, platinum / ruthenium, platinum / renium, palladium / ruthenium, palladium / renium, cobalt / palladium, cobalt / platinum, cobalt / chromium, cobalt / ruthenium, silver / palladium, Copper / palladium, nickel / palladium, gold / palladium, ruthenium / renium and ruthenium / iron. Exemplary catalysts are further described in US Pat. Nos. 7,608,744 and 7,863,489, and US Patent Publication No. 2010/0197485, which are incorporated herein by reference.

In one exemplary embodiment, the catalyst is 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 It includes. Preferably, the first metal is selected from the group consisting of platinum, palladium, cobalt, nickel and ruthenium. More preferably, the first metal is selected from platinum and palladium. If the first metal comprises platinum, it is preferred that the catalyst comprises platinum in an amount of less than 5%, for example less than 3%, or less than 1% by weight because of the high platinum demand.

As indicated above, the catalyst optionally further comprises a second metal, which typically acts as an accelerator. When present, the second metal is preferably selected from the group consisting of 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 the group consisting of 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 the first metal and the second metal, the first metal is optionally from 0.1% to 10% by weight, for example from 0.1% to 5% or from 0.1% to 3% by weight. Present in the catalyst in an amount of%. The second metal is preferably present in an amount of 0.1% to 20% by weight, such as 0.1% to 10% by weight, or 0.1% to 5% by weight. In the case of a catalyst comprising two or more metals, two or more metals may be alloyed with each other, or two or more metals may comprise a non-alloyed metal solution or mixture.

Preferred metal ratios may vary depending on the metal used in the catalyst. In some exemplary embodiments, the molar ratio of the first metal to the second metal is from 10: 1 to 1:10, such as from 4: 1 to 1: 4, from 2: 1 to 1: 2, 1.5, or 1.1: 1 to 1: 1.1.

The catalyst may also comprise a third metal selected from any of the metals listed above in relation to the first metal or the second metal, provided the third metal is different from the first metal and the second metal. In a preferred embodiment, the third metal is selected from the group consisting of cobalt, palladium, ruthenium, copper, zinc, platinum, tin and rhenium. More preferably, the third metal is selected from cobalt, palladium and ruthenium. If present, the total weight of the third metal is preferably 0.05% to 4% by weight, such as 0.1% to 3% by weight, or 0.1% to 2% by weight.

In addition to one or more metals, exemplary catalysts further include a support or modified support, which means a support comprising a support material and a support modifier that modulates the acidity of the support material. The total weight of the support or modified support is from 75 wt% to 99.9 wt%, for example from 78 wt% to 97 wt%, or from 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 from 0.1 wt% to 50 wt%, for example from 0.2 wt% to 25 wt%, from 0.5 wt% to 15 wt%, or 1 based on the total weight of the catalyst. It is present in an amount of from 8% by weight.

Suitable support materials can include, for example, suitable metal oxide-based supports or ceramic-based supports. Preferred supports include silicon-like supports such as silica, silica / alumina, group IIA silicates such as calcium metasilicate, pyrolytic silica, high purity silica and mixtures thereof. Other supports may include, but are not limited to, iron oxide, alumina, titania, zirconia, magnesium oxide, carbon, graphite, graphitized carbon with high surface area, activated carbon, and mixtures thereof.

In the preparation of ethanol, the catalyst support can be modified with a support modifier. Preferably, the support modifier is a basic modifier with low or no volatility. Such basic modifiers include, for example, (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 metasilicate, (vii) group IIIB metal oxide, (viii) group IIIB metal metasilicate, and mixtures thereof. In addition to oxides and metasilicates, other types of modifiers can be used, including nitrates, nitrites, acetates, and lactates. Preferably, the support modifier is selected from the group consisting of oxides and metasilicates of any of sodium, potassium, magnesium, calcium, scandium, yttrium and zinc as well as mixtures of any of the above. Preferably, the support modifier is calcium silicate, more preferably calcium metasilicate (CaSiO ₃ ). If the support modifier comprises calcium metasilicate, it is preferred that at least a portion of the calcium metasilicate is in crystalline form.

Preferred silica support materials are SS61138 high surface area (HSA) silica catalyst carriers from Saint Gobain NorPro. St-Govine Nopro SS61138 Silica contains about 95% by weight high surface area silica and has a surface area of about 250 m ² / g; Median pore diameter of about 12 nm; It has an average pore volume of about 1.0 cm ³ / g and a packing density of about 0.352 g / cm ³ (22 lb / ft ³ ) measured by mercury penetration porosimetry.

Preferred silica / alumina support materials have a nominal diameter of about 5 mm, a density of about 0.562 g / ml, an absorption of about 0.583 g H ₂ O per gram of support, a surface area of about 160 to 175 m ² / g and a pore of about 0.68 ml / g KA-160 (Sud Chemie) silica spheres with volume.

As will be appreciated by those skilled in the art, the support material is chosen such that the catalyst system is suitably active, selective and robust under the process conditions used to produce ethanol.

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

Catalyst compositions suitable for use in the present invention are preferably prepared through metal impregnation of the modified support, but other methods such as chemical vapor deposition can also be used. Such impregnation techniques are described in U.S. Patent Nos. 7,608,744 and 7,863,489, and U.S. Patent Publication No. 2010/0197485, which are incorporated herein by reference.

Some embodiments of the method of hydrogenating acetic acid to produce ethanol in accordance with one embodiment of the present invention may include various configurations using a fixed bed reactor or fluidized bed reactor as those skilled in the art will readily appreciate. In many embodiments of the present invention, a "insulation" reactor can be used, ie, little or no internal piping through the reaction zone is required to add or remove heat. In other embodiments, radial flow reactors or reactors may be used, or a series of reactors may be used with or without heat exchange, quenching or the introduction of additional feed material. Alternatively, a shell and tube reactor provided with a heat transfer medium can be used. In many cases, the reaction zone may be contained in a single vessel or in a series of vessels with heat exchangers therebetween.

In a preferred embodiment, the catalyst is used, for example in a fixed bed reactor in the form of a pipe or tube, in which the reactants, typically in vapor form, pass over or through the catalyst. Other reactors may be used, such as fluidized bed or ebullient bed reactors. In some cases, hydrogenation catalysts may be used in combination with inert materials to adjust the pressure drop of the reactant stream through the catalyst bed and the contact time of the reactant compound with the catalyst particles.

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

Optionally, hydrogenation is carried out at a pressure sufficient to overcome the pressure drop across the catalyst bed in the selected GHSV, but the use of higher pressures is not prohibited, and high space velocities such as 5000 hours ^-1 or 6,500 hours ^-1 It is contemplated that a significant pressure drop through the reactor bed may be encountered.

The reaction consumes 2 moles of hydrogen per mole of acetic acid to produce 1 mole of ethanol, but the actual molar ratio of hydrogen to acetic acid in the feed stream is about 100: 1 to 1: 100, for example 50: 1 to 1:50, 20: 1 to 1: 2, or 12: 1 to 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.

The contact or residence time can also vary widely depending on variables such as the amount of acetic acid, catalyst, reactor, temperature and pressure. Typical contact times range from less than 1 second to several hours or more when catalyst systems other than stationary phases are used, with preferred contact times being at least 0.1 to 100 seconds, such as 0.3 to 80 seconds or 0.4 to 30 seconds for vapor phase reactions. .

The raw materials used in connection with the process of the invention, namely acetic acid and hydrogen, can be derived from any suitable source, including natural gas, petroleum, coal, biomass and the like. As an example, acetic acid can be produced through methanol carbonylation, acetaldehyde oxidation, ethylene oxidation, oxidative fermentation and anaerobic fermentation. As oil and natural gas prices fluctuate (better or cheaper), there has been a growing interest in the production of intermediates such as acetic acid and methanol and carbon monoxide from other carbon sources. In particular, where petroleum is relatively expensive compared to natural gas, it may be advantageous to produce acetic acid from syngas ("syngas") derived from any available carbon source. For example, US Pat. No. 6,232,352, incorporated herein by reference, teaches a method of retrofitting a methanol plant to produce acetic acid. By retrofitting a methanol plant, the large capital costs associated with carbon monoxide generation of the new acetic acid plant are significantly reduced or significantly eliminated. All or part of the synthesis gas is branched from the methanol synthesis loop and fed to a separation unit to recover carbon monoxide and hydrogen, which is again used to produce acetic acid. In addition to acetic acid, this method may also be used to produce hydrogen that may be used in connection with the present invention.

Suitable methanol carbonylation methods for the production of acetic acid 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 carbonyl method.

US Reissue Patent No. 35,377, also incorporated herein by reference, provides a method for producing methanol by conversion of carbonaceous materials such as oil, coal, natural gas and biomass materials. The method involves hydrogenating a solid and / or liquid carbonaceous material to obtain a process gas, which is pyrolyzed with additional natural gas to form a synthesis gas. The synthesis gas can be converted to methanol and carbonylated to produce acetic acid. This method likewise produces hydrogen which can be used in connection with the present invention as indicated above. US Pat. No. 5,821,111 and US Pat. No. 6,685,754, which disclose methods of converting waste biomass to syngas via gasification, are incorporated herein by reference.

In one optional embodiment, the acetic acid feed stream fed to the hydrogenation reaction contains acetic acid and may include other carboxylic acids such as propionic acid, esters and anhydrides as well as acetaldehyde and acetone. In one embodiment, the acetic acid fed to the hydrogenation reaction comprises propionic acid. For example, propionic acid in the acetic acid feed stream is 0.001% to 15% by weight, such as 0.001% to 0.11%, 0.125% to 12.5%, 1.25% to 11.25%, or 3.75% to 8.75% It can reach%. Thus, the acetic acid feed stream may be a more crude acetic acid feed stream, for example a less refined acetic acid feed stream. In these embodiments, propionic acid in the acetic acid feed stream is hydrogenated to form n-propanol, which can act as a modifier. n-propanol is modified ethanol in an amount of 0.001% to 15% by weight, such as 0.001% to 0.11%, 0.13% to 13.2%, 1.3% to 11.9%, or 4% to 9.3% by weight. May be present in the composition.

Alternatively, acetic acid in vapor form can be obtained directly as a crude product from a flash vessel of the methanol carbonylation unit of the class described in US Pat. No. 6,657,078, which is incorporated herein by reference. For example, the crude vapor product can be fed directly into the ethanol synthesis reaction zone of the present invention without the need to condense acetic acid and light ends compounds or remove water, thereby reducing overall processing costs.

In one embodiment, acetone is added to the reactor as reactant in addition to acetic acid and hydrogen. Without being bound by a particular theory, it is believed that adding acetone to the reaction produces isopropanol, which can act as a modifier. In another embodiment, acetone is formed as a byproduct of the hydrogenation of acetic acid. After production, acetone can be hydrogenated to produce isopropanol as a modifier. In some embodiments where isopropanol modifiers are required, separate catalysts are used to obtain higher concentrations of acetone, which results in higher concentrations of isopropanol in the crude ethanol composition in subsequent hydrogenation. For example, a catalyst composition comprising a support such as TiO ₂ , ZrO ₂ , Fe ₂ O _3, or CeO ₂ can be used. Other exemplary catalyst compositions include ruthenium supported by SiO ₂ , iron supported by carbon, or palladium supported by carbon.

In one embodiment, acetone is produced in the auxiliary reaction carried out in the auxiliary acetone reactor. For example, acetic acid can be reacted in a secondary reactor under conditions effective to form acetone (eg, ketoneization). The acetic acid fed to the auxiliary reactor may be withdrawn from the acetic acid feed stream fed to the hydrogenation reactor. The auxiliary reactor may be of the type discussed above. For example, the auxiliary reactor may be a fixed bed reactor in which a catalyst is disposed. Preferably, the auxiliary reactor is in the form of a pipe or tube, where typically a reactant in the form of steam passes over or through a catalyst placed in the pipe or tube. In some embodiments, the auxiliary reactor uses a catalyst which promotes ketoneization and / or is preferred for producing acetone. For example, the catalyst may comprise a basic catalyst such as thorium oxide. In some embodiments, acetone obtained by the auxiliary reactor is sent to the hydrogenation reactor as a reactant in addition to acetic acid and hydrogen.

After evaporating acetic acid at the reaction temperature, the vaporized acetic acid can be fed with hydrogen without dilution, or diluted with a relatively inert carrier gas such as nitrogen, argon, helium, carbon dioxide and the like. For reactions performed in the vapor phase, the temperature must be controlled in the system so that the temperature does not fall below the dew point of acetic acid. In one embodiment, acetic acid may be vaporized at the boiling point of acetic acid at a certain pressure, and then the vaporized acetic acid may be further heated to the reactor inlet temperature. In other embodiments, the acetic acid is changed to a vapor state by passing hydrogen, recycle gas, other suitable gas, or mixtures thereof through acetic acid at a temperature below the boiling point of acetic acid, whereby the carrier gas is wetted with acetic acid vapor and then The mixed steam is heated to the reactor inlet temperature. Preferably, the acetic acid is converted to steam by passing hydrogen and / or recycle gas through acetic acid at a temperature of 125 ° C. or lower, and then the combined gaseous stream is heated to the reactor inlet temperature.

In particular, hydrogenation of acetic acid can achieve the desired conversion of acetic acid and the desired selectivity and yield to ethanol. As used herein, the term "conversion rate" refers to the amount of acetic acid in a feed that is converted to a compound other than acetic acid. The conversion is expressed as mole% based on acetic acid in the feed. The conversion may be at least 10%, for example at least 20%, at least 40%, at least 50%, at least 60%, at least 70% or at least 80%. Catalysts having a high conversion of at least 80% or at least 90% are preferred, but in some embodiments a low conversion at high selectivity to ethanol may be acceptable. Of course, in many cases, conversion can be supplemented by the use of appropriate recycle streams or larger reactors, but it is widely known that it is more difficult to compensate for poor selectivity.

Selectivity is expressed as mole% based on the converted acetic acid. It is to be understood that each compound converted from acetic acid has independent selectivity, and the selectivity is independent of the conversion rate. For example, when 50 mole percent of the converted acetic acid is converted to ethanol, ethanol selectivity is referred to as 50%. Preferably, the catalyst selectivity to ethoxylate is at least 60%, for example at least 70%, or at least 80%. The term "ethoxylate" as used herein specifically refers to 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 the hydrogenation process also have low selectivity to undesirable products such as methane, ethane and carbon dioxide. Selectivity to these undesired moles is preferably less than 4%, for example less than 2% or less than 1%. More preferably, these undesirable products are not detected. The formation of the alkane may be low and ideally less than 2%, less than 1%, or less than 0.5% of the acetic acid passed over the catalyst is converted to an alkane with little value other than fuel.

The term "production rate" as used herein refers to the number of stated products, such as ethanol, produced during hydrogenation, based on 1 kg of catalyst used per hour. Preference is given to a production rate of at least 200 g of ethanol, such as at least 400 g or at least 600 g per kg of catalyst per hour. In the range, the production rate is preferably 200 to 3,000 g of ethanol per kg of catalyst per hour, for example 400 to 2500 g or 600 to 2,000 g.

In various embodiments, the crude ethanol product produced by the hydrogenation process typically comprises unreacted acetic acid, ethanol and water prior to any subsequent processing such as purification and separation. The term "crude ethanol product" as used herein refers to any composition comprising 5% to 70% by weight of ethanol and 5% to 35% by weight of water. In some exemplary embodiments, the crude ethanol product is present in an amount of from 5% to 70% by weight, for example from 10% to 60% by weight or from 15% by weight to 50% by weight, based on the total weight of the crude ethanol product, It includes. Preferably, the crude ethanol product comprises at least 10% ethanol, at least 15% ethanol, or at least 20% ethanol.

The crude ethanol product typically further comprises unreacted acetic acid, for example in an amount of less than 90% by weight, such as less than 80% by weight, or less than 70% by weight, depending on the conversion rate. In the range, unreacted acetic acid is preferably in an amount of 0 to 90% by weight, such as 5% to 80% by weight, 15% to 70% by weight, 20% to 70% by weight or 25% to 65% by weight. Exist. When acetone is included as a reactant, the crude ethanol product is 0.01 to 10 weight percent, for example 0.1 to 10 weight percent, 1 to 9 weight percent, or 3 to 7 weight percent isopropanol It may include. In another embodiment, the crude ethanol product comprises from 0.01 wt% to 20 wt%, such as from 0.1 wt% to 10 wt%, from 1 wt% to 9 wt%, or from 3 wt% to 7 wt% diethyl ether. Since water is produced in the reaction process, the crude ethanol product will typically comprise water in an amount of, for example, 5% to 35% by weight, for example 10% to 30% by weight or 10% to 26% by weight. . Ethyl acetate may also be produced during the hydrogenation of acetic acid or through side reactions. In these embodiments, the crude ethanol product comprises ethyl acetate in an amount of 0 to 20 wt%, such as 0 to 15 wt%, 1 to 12 wt%, or 3 to 10 wt%. It can be produced as acetaldehyde through side reactions. In these embodiments, the crude ethanol product comprises acetaldehyde in an amount of 0 to 10% by weight, for example 0 to 3%, 0.1 to 3%, or 0.2 to 2% by weight. In some embodiments in which propionic acid is included as a reactant, the n-propanol produced through hydrogenation is 0.001% to 15% by weight, for example 0.001% to 0.11%, 0.13% to 13.2%, 1.3% To 11.9% by weight, or 4% to 9.3% by weight in the crude ethanol product.

Thus, the hydrogenation reaction produces a crude ethanol product which may in particular contain a denaturant such as acetic acid, isopropanol, ethyl acetate, diethyl ether, acetaldehyde and / or n-propanol. Each of the compounds produced within these in situ can act alone or together with one another as a modifier in the modified ethanol composition. In some embodiments, all or a portion of the crude ethanol product may be combined with a purified ethanol stream to form a modified ethanol composition. It is within the scope of the present invention to adjust the reaction parameters to achieve the desired crude ethanol product, thus the desired modified ethanol composition. In one embodiment, the amount of reactants fed to the hydrogenation reactor, such as acetic acid, acetone and / or propionic acid, may be adjusted to achieve a specific amount of one or more components of the crude ethanol product, such as denaturant. The resulting denaturant may be combined with a purified ethanol stream to produce a modified ethanol composition. For example, by feeding an acetic acid stream comprising acetic acid and acetone, a denatured ethanol composition comprising about 5 parts of isopropanol relative to 100 parts of ethanol can be produced. As another example, a modified ethanol composition comprising about 5 parts of n-propanol relative to 100 parts of ethanol can be produced by feeding an acetic acid stream comprising acetic acid and propionic acid. It is also within the scope of the present invention to adjust additional hydrogenation reactor parameters to achieve a crude ethanol product comprising the desired amount of a specific modifier or combination of modifiers. For example, to produce a crude ethanol product comprising about 10 parts of diethyl ether, co-pending US patent application Ser. No. 12 / 850,414 filed Aug. 4, 2010, entitled "Diethyl from Acetic Acid." Quot ;, the disclosure of which is incorporated herein by reference in its entirety), which is incorporated herein by reference in its entirety.

In one embodiment, it is difficult to separate isopropanol and ethanol from each other, so that all or some of the isopropanol formed in the hydrogenation reaction can follow the ethanol through a separation scheme.

Since the crude ethanol composition as formed may contain the modifying agent (s) produced in situ, at least a portion of the crude ethanol composition, further separated or not separated, is combined with the purified ethanol stream to prepare a modified ethanol composition. can do. In one embodiment, one or more denaturants formed in situ may be separated from the crude ethanol product and combined with the purified ethanol stream. In other embodiments, at least some, such as aliquots, of the crude ethanol product can be combined with the purified ethanol stream. For example, where the crude ethanol product comprises n-propanol, at least a portion of the n-propanol-containing crude ethanol product can be combined with the purified ethanol stream to produce a modified ethanol composition comprising an n-propanol modifier . In other embodiments, at least some of the n-propanol is separated from the crude ethanol product and combined with the purified ethanol stream to produce an n-propanol modified ethanol composition. As another example, where acetic acid is the desired denaturant, at least a portion of the acetic acid-containing crude ethanol composition may be combined with a purified ethanol stream to produce a modified ethanol composition comprising an acetic acid modifier. In other embodiments, an acetic acid-modified ethanol composition can be prepared by combining at least a portion of acetic acid in the acetic acid feed and / or any acetic acid recycle stream with a purified ethanol stream.

When detectable, other components such as ester, ether, aldehyde, ketone, alkane and carbon dioxide may all be present in an amount of less than 10% by weight, for example less than 6% by weight, or less than 4% by weight. In a range, the crude ethanol composition may comprise other components in an amount of 0.1% to 10% by weight, for example 0.1% to 6% by weight, or 0.1% to 4% by weight. Exemplary embodiments of crude ethanol composition ranges are provided in Table 1.

Crude Ethanol Product Composition ingredient Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) ethanol 5 to 70 10 to 60 15 to 50 25-50 Acetic acid 0 to 90 5 to 80 15 to 70 20 to 70 water 5 to 35 5 to 30 10 to 30 10 to 26 Ethyl acetate 0 to 20 0 to 15 1 to 12 3 to 10 Acetaldehyde 0 to 10 0 to 3 0.1 to 3 0.2 to 2 Etc 0.1 to 10 0.1 to 6 0.1 to 4 -

As described in Table 1, in some embodiments the crude ethanol product may be a modified ethanol composition. For example, the crude ethanol composition may comprise ethanol and one or more denaturing agents such as acetic acid, ethyl acetate or acetaldehyde. In other embodiments, the crude ethanol composition may be a modified ethanol composition comprising one or more of the modifiers discussed above.

1A shows a hydrogenation system 100 suitable for hydrogenating acetic acid and separating ethanol from the crude reaction mixture in accordance with one embodiment of the present invention. System 100 includes a reaction zone 101 and a distillation zone 102. The reaction zone 101 includes a reactor 103, a hydrogen supply line 104 and an acetic acid supply line 105. In another embodiment using acetone as a reactant, reaction zone 101 further comprises an acetone feed line (not shown). In another embodiment using propionic acid as the denaturant, reaction zone 101 further comprises a propionic acid feed line (not shown). Distillation zone 102 includes a flasher 106, a first column 107, a second column 108, and a third column 109. Hydrogen, acetic acid and optionally acetone and / or propionic acid are fed via vaporizer 110 via lines 104 and 105, respectively, to produce a vapor feed stream in line 111 directed to reactor 103. In one embodiment, lines 104 and 105 are combined and fed together to vaporizer 110 (eg, in one stream containing both hydrogen and acetic acid). The temperature of the steam feed stream in line 111 is preferably 100 ° C. to 350 ° C., for example 120 ° C. to 310 ° C., or 150 ° C. to 300 ° C. Any feed that has not been vaporized can be removed from the vaporizer 110 and recycled as shown in FIG. 1A. Also, while FIG. 1A shows line 111 facing the top of reactor 103, line 111 may be directed to the side, top or bottom of reactor 103. Although one reactor and one flasher are shown in FIGS. 1A, 1B and 1C, various optional embodiments of the present invention may include additional reactors and / or components. For example, the hydrogenation system can optionally include a dual reactor, dual flasher, heat exchanger (s) and / or preheater (s).

Reactor 103 contains a catalyst used for the hydrogenation of carboxylic acids, preferably acetic acid. In some embodiments where acetone is the reactant and isopropanol is a co-product of the desired ethanol, the catalyst of reactor 103 is selected such that isopropanol is also produced in addition to ethanol. By way of example, catalyst compositions comprising a support such as TiO ₂ , ZrO ₂ , Fe ₂ O ₃ or CeO ₂ can be used. In some embodiments, these catalysts promote higher acetone production. Other exemplary catalyst compositions include ruthenium supported by SiO ₂ , iron supported by carbon or palladium supported by carbon. In other embodiments, the temperature of reactor 103 can be adjusted to achieve the desired isopropanol concentration. For example, when the reaction temperature is maintained at 200 ° C to 350 ° C, such as 225 ° C to 300 ° C, 0.1 to 10% by weight of isopropanol, for example 1 to 9% or 3 to 7% by weight It is possible to produce an ethanol composition comprising%. In one embodiment, one or more guard beds (not shown) may be used to protect the catalyst from toxins or undesirable impurities contained in the feed stream or return / recycle stream. Such protective layers can be used in the vapor or liquid streams. Suitable protective layer materials are known in the art and include, for example, carbon, silica, alumina, ceramics or resins. In one embodiment, the protective layer medium has a function to capture specific substances such as sulfur or halogens. During the hydrogenation process, the crude ethanol product stream is withdrawn from reactor 103 via line 112, preferably continuously. The crude ethanol product stream is condensed and fed to flasher 106, which in turn provides a vapor stream and a liquid stream. The flasher 106 in one embodiment is preferably operated at a temperature of 50 ° C. to 500 ° C., for example 70 ° C. to 400 ° C., or 100 ° C. to 350 ° C. In one embodiment, the pressure of the flasher 106 is preferably 50 KPa to 2000 KPa, such as 75 KPa to 1500 KPa, or 100 to 1000 KPa. In one preferred embodiment, the temperature and pressure of the flasher 106 are similar to the temperature and pressure of the reactor 103.

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

The liquid from the flasher 106 is recovered and pumped via line 115 to the side of the first column 107 (also called an acid separation column) as the feed composition. The content of line 115 is typically substantially similar to the product obtained directly from the reactor, and may actually be characterized as crude ethanol product. However, the feed composition of line 115 is preferably substantially free of hydrogen, carbon dioxide, methane or ethane removed by flasher 106. Exemplary components of the liquid in line 115 are provided in Table 2. It should be appreciated that liquid line 115 may contain other components not listed, such as those in the feed.

Feed composition Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) ethanol 5 to 70 10 to 60 15 to 50 water 5 to 35 5 to 30 10 to 30 Acetic acid (denaturant) <90 5 to 80 15 to 70 Ethyl acetate (modifier) <20 0.001 to 15 1 to 12 Acetaldehyde (modifier) <10 0.001 to 3 0.1 to 3 Acetal <5 0.001 to 2 0.005 to 1 Acetone <5 0.0005 to 0.05 0.001 to 0.03 Other ester <5 <0.005 <0.001 Other ether <5 <0.005 <0.001 Other alcohol <5 <0.005 <0.001

Amounts less than (<) in the tables throughout this application are preferably not present and may be present in minor amounts or in amounts greater than 0.0001% by weight, when present.

"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 is 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, the feed composition, such as line 115, advantageously has a small amount of propanol, for example isopropanol and / or n-propanol, such as from 0.001% to 0.1%, from 0.001% to 0.05% by weight. Or 0.001% to 0.03% by weight. As a result of the low concentrations of these alcohols, the resulting modified ethanol compositions advantageously contain only minor amounts of these alcohols (see discussion below). These traces are significantly lower than the levels obtained through the process without utilizing the hydrogenation of acetic acid. In other embodiments, the concentration of isopropanol in the feed composition is higher (eg, 0.01-10% by weight). In other embodiments, the concentration of n-propanol in the feed composition is higher (eg, 0.01 to 10 weight percent). In other embodiments, the concentration of diethyl ether in the feed composition is higher (eg, 0.01-20% by weight). It should be appreciated that these other components may be delivered via any of the distillate or residue streams described herein. In addition, as indicated above, some of these other components, such as isopropanol or diethyl ether, may also be used as the modifier.

If the content of acetic acid in line 115 is less than 5% by weight, the acid separation column 107 can be skipped, and line 115 goes directly to the second column 108, also referred to herein as the light fraction column. Can be introduced.

In the embodiment shown in FIG. 1A, line 115 is introduced into the bottom of first column 107, for example, bottom half or bottom third. In the first column 107, unreacted acetic acid, some of the water and, if present, other heavy components are removed from the composition of line 115 and preferably recovered 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 produces overhead distillate, which is recovered in line 117 and condensed, such as 10: 1 to 1:10, for example 3: 1 to 1: 3. Or reflux in a ratio of 1: 2 to 2: 1.

Any column 107, 108 or 109 can include any distillation column that can be separated and / or purified. The column preferably comprises a tray column having 1 to 150 trays, for example 10 to 100 trays, 20 to 95 trays, or 30 to 75 trays. The tray may be a sieve tray, fixed valve tray, moving valve tray, or any other suitable design known in the art. In other embodiments, packed columns can be used. For packed columns, structured packing or random packing can be used. Trays or packings can be arranged in one continuous column or they can be arranged in two or more columns such that vapor from the first zone enters the second zone while liquid from the second zone enters the first zone. have.

The associated condenser and liquid separation vessel that can be used with each distillation column can be of any conventional design and is simplified in FIGS. 1A, 1B and 1C. As shown in FIGS. 1A, 1B, and 1C, heat may be supplied to the bottom of each column or to the bottom stream circulated through a heat exchanger or reboiler. Other types of reboilers, such as internal reboilers, may also be used in some embodiments. The heat provided to the reboiler can be derived from any heat generated during the process of integrating with the reboiler or from an external source such as another exothermic chemical process or boiler. While one reactor and one flasher are shown in FIGS. 1A, 1B and 1C, additional reactors, flashers, condensers, heating elements and other components may be used in embodiments of the present invention. As will be appreciated by those skilled in the art, various condensers, pumps, compressors, reboilers, drums, valves, coupling devices, separation vessels, and the like, commonly used to perform chemical processes, may also be used in combination in the process of the present invention.

The temperature and pressure used in any column may vary. In practice, pressures of 10 KPa to 3000 KPa are typically used in these zones, but in some embodiments pressures below atmospheric pressure as well as pressures above atmospheric pressure may be used. The temperature in the various zones is usually 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 appreciate that the temperature at a given location of the distillation column to be operated depends on the composition of the material at that location and the pressure of the column. In addition, the feed rate may vary depending on the size of the manufacturing process, and may be referred to generically as the feed weight ratio when described.

When column 107 is operated under standard atmospheric pressure, the temperature of the residue exiting line 116 from column 107 is preferably between 95 ° C and 120 ° C, for example between 105 ° C and 117 ° C or between 110 ° C and 115 ° C. to be. The temperature of the distillate exiting line 117 from column 107 is preferably 70 ° C. to 110 ° C., such as 75 ° C. to 95 ° C. or 80 ° C. to 90 ° C. In other embodiments, the pressure of the first column 107 may be 0.1 KPa to 510 KPa, for example 1 KPa to 475 KPa or 1 KPa to 375 KPa. Exemplary components of the distillate and residue composition of the first column 107 are provided in Table 3 below. It should also be appreciated that 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 of other columns may also be referred to with similar numerical modifiers (second, third, etc.) to distinguish from one another, but such modifiers should not be considered to require any particular order of separation.

First column Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) Distillate ethanol 20 to 75 30 to 70 40 to 65 water 10 to 40 15 to 35 20 to 35 Acetic acid <2 0.001 to 0.5 0.01 to 0.2 Ethyl acetate (modifier) <60 5.0 to 40 10 to 30 Acetaldehyde (modifier) <10 0.001 to 5 0.01 to 4 Isopropanol (modifying agent) 0.02 to 7.5 0.3 to 6.5 1.2 to 5 n-propanol (modifier) 0.02 to 7.5 0.3 to 6.5 1.2 to 5 Diethyl ether (modifier) 0.02 to 7.5 0.3 to 6.5 1.2 to 5 Acetal <0.1 <0.1 <0.05 Acetone <0.05 0.001 to 0.03 0.01 to 0.025 Residue Acetic acid 60 to 100 70 to 95 85 to 92 water <30 1 to 20 1 to 15 ethanol <1 <0.9 <0.07

As described in Table 3, distillates and / or residuals are detected when any amount of acetal is detected in the feed introduced into the acid separation column [first column 107] without being bound by a particular theory. It was surprisingly and unexpectedly found that acetal appears to decompose in the column so that little or even no detectable amount is present in the water.

Depending on the reaction conditions, the crude ethanol product exiting reactor 103 in line 112 may include ethanol, acetic acid (unconverted), ethyl acetate and water. After exiting the reactor 103, an unbalanced equilibrium reaction may occur between the components contained in the crude ethanol product until the crude ethanol product is added to the flasher 106 and / or the first column 107. This equilibrium reaction tends to lead the crude ethanol product to an equilibrium between ethanol / acetic acid and ethyl acetate / water as shown below:

If the crude ethanol product is temporarily stored, for example in a holding tank, before heading to the distillation zone 102, longer residence times may be experienced. In general, the longer the residence time between reaction zone 101 and distillation zone 102, the greater the amount of ethyl acetate produced. For example, if the residence time between reaction zone 101 and distillation zone 102 is longer than five days, significantly more ethyl acetate can be produced instead of ethanol. Therefore, it is usually desirable to have a shorter residence time between reaction zone 101 and distillation zone 102 to maximize ethanol production. In one embodiment, a holding tank between the reaction zone 101 and the distillation zone 102 to temporarily store the liquid component from line 115 for up to 5 days, for example up to 1 day or up to 1 hour. Not shown). In a preferred embodiment, no tank is included, and the condensed liquid is fed directly to the first distillation column 107. Also, for example, as the temperature of the crude ethanol product in line 115 increases, the rate at which unpromoted reactions occur may increase. These reaction rates can be particularly problematic at temperatures above 30 ° C, for example above 40 ° C or above 50 ° C. Therefore, in one embodiment, the temperature of the liquid component in line 115 or any holding tank is maintained below 40 ° C, such as below 30 ° C or below 20 ° C. One or more cooling devices may be used to reduce the temperature of the liquid in line 115.

As discussed above, optionally storing the liquid component from line 115 temporarily at about 21 ° C. and correspondingly for example for 1 to 24 hours, respectively, corresponding to 0.01% to 1.0% by weight of ethyl acetate production, respectively. For example, a holding tank (not shown) may be included between the reaction zone 101 and the distillation zone 102. In addition, as the temperature of the crude ethanol product increases, the rate at which unpromoted reactions occur may increase. For example, as the temperature of the crude ethanol product in line 115 increases from 4 ° C. to 21 ° C., the ethyl acetate production rate may increase from about 0.01% by weight to about 0.005% by weight per hour. Therefore, in one embodiment, the temperature of the liquid component in line 115 or any holding tank is maintained at a temperature below 21 ° C., for example below 4 ° C. or below −10 ° C.

In addition, it has recently been found that the equilibrium reaction may also be desirable for ethanol formation in the top region of the first column 107.

Distillates, such as overhead streams, from the first column 107 are optionally condensed and refluxed, as shown in FIGS. 1A-1C, preferably at a reflux ratio of 1: 5 to 10: 1. The distillate of line 117 is ethanol; In situ denaturants such as ethyl acetate and / or acetaldehyde; Water, and other impurities that may be difficult to separate because of the formation of binary azeotrope and ternary azeotrope. The first distillate also contains a significantly reduced amount of acetic acid. As shown in FIG. 1C, in some embodiments, the distillate of the first column (without further processing) is comprised between 0.0001% and 80% by weight, for example between 0.001% and 60% by weight, and 20% by weight of ethanol. To 75% by weight, such as 30% to 70% by weight modified ethanol composition. Preferably, the denaturing agent of these embodiments is ethyl acetate. In another embodiment, the distillate of the first column (without further processing) is comprised between 0.0001% to 10% by weight, such as 0.001% to 5% or 0.01% to 4% by weight, and 20% to 75% ethanol Modified ethanol composition comprising, for example, 30% to 70% by weight. Preferably, the denaturing agent in these embodiments is acetaldehyde.

In other embodiments, at least a portion of the first distillate may be combined with the purified ethanol stream via optional line 117 ′ to produce a modified ethanol composition. Preferably, the denaturant comprises ethyl acetate and / or acetaldehyde. In other embodiments, at least a portion of the first distillate may be fed to additional columns, for example third columns, as discussed below. As a result, the denaturant (s) in the first distillate, such as ethyl acetate and / or acetaldehyde, can be conveyed into the distillate of the third column. As such, the third distillate may be a modified ethanol composition comprising the modifier (s) from the first distillate. In these embodiments, the weight percent of the modifying agent (s) in the modified ethanol composition may be as discussed above. The weight ratio of denaturant-containing stream, such as line 117 and purified ethanol stream, varies widely and can be adjusted to achieve the desired specific concentration of denaturant in the modified ethanol composition. For example, the weight ratio of purified ethanol stream to denaturant-containing stream may be 0.01: 1 to 5: 1, such as 0.05: 1 to 3: 1.

As discussed above, the residue from the first column 107 contains a large amount of unreacted acetic acid. Thus, in another embodiment, at least a portion of the first residue can be combined with the purified ethanol stream to produce the acetic acid-modified ethanol composition.

Advantageously, the modified ethanol compositions are produced without further separation steps using the modifiers produced in situ via a hydrogenation reaction. This eliminates the need for providing an additional external source of denaturant or combining the denaturant with purified ethanol, which eliminates processing steps and simplifies the overall process. Further purification of the first column distillate, such as removal of additional water and / or acetaldehyde, is also within the scope of the present invention. Conventional separation methods can be used to achieve this additional purification.

As shown in Table 3, the first residue contains a significant amount of unreacted acetic acid, which can be recycled back to the reactor 103 as shown in FIGS. 1A, 1B and 1C.

The first distillate of line 117 is introduced into a second column 108, also referred to as a “light column”, preferably in the middle of the column 108, such as the middle half or the middle third. do. The second column 108 can be a tray column or a packed column. In one embodiment, the second column 108 is a tray column having 5 to 70 trays, for example 15 to 50 trays, or 20 to 45 trays.

As an example, if a 25 tray column is used for the column without water extraction, line 117 is introduced into tray 17. If the second column is not an extractive distillation column, it is expected that ethyl acetate in line 117 may be separated into the second residue along with ethanol and water. As a result, in one embodiment, more ethyl acetate can be fed to the third column 109, so that ethyl acetate can be present in the third distillate. In other embodiments, at least a portion of the ethyl acetate-containing second residue can be combined with the purified ethanol stream to produce a modified ethanol composition.

However, in a preferred embodiment, the second column 108 may be an extractive distillation column. In an extractive distillation column, it is expected that ethyl acetate in line 117 may be separated from ethanol and water and passed into the second distillate. In such embodiments, an extractant such as water may optionally be added to the second column 108 via line 127. If the extractant comprises water, it may be obtained from an internal return / recycle line from an external source or from one or more other columns. In a preferred embodiment, water in the third residue of the third column 109 is used as extractant. As shown in FIGS. 1A, 1B and 1C, the third residue may optionally be directed to the second column 108 via line 121 ′.

The temperature and pressure of the second column 108 may vary, but in the case of atmospheric pressure the temperature of the second residue leaving line 118 from the second column 108 is preferably between 60 ° C. and 90 ° C., for example 70-90 degreeC or 80-90 degreeC. The temperature of the second distillate leaving the line 120 from the second column 108 is preferably from 50 ° C. to 90 ° C., for example from 60 ° C. to 80 ° C., or from 60 ° C. to 70 ° C. Column 108 may be operated at atmospheric pressure. In other embodiments, the pressure of the second column 108 may be 0.1 KPa to 510 KPa, for example 1 KPa to 475 KPa or 1 KPa to 375 KPa. Exemplary components of the distillate and residue composition of the second column 108 are provided in Table 4 below. It should be noted that distillates and residues may also contain other components not listed, such as components in the feed.

Second column Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) Distillate Ethyl acetate (modifier) 10 to 90 25 to 90 50 to 90 Acetaldehyde (modifier) 1 to 25 1 to 15 1 to 8 water 1 to 25 1 to 20 4 to 16 ethanol <30 0.001 to 15 0.01 to 5 Acetal <5 0.001 to 2 0.01 to 1 Residue water 30 to 70 30 to 60 30 to 50 ethanol 20 to 75 30 to 70 40 to 70 Ethyl acetate <3 0.001 to 2 0.001 to 0.5 Acetic acid <0.5 0.001 to 0.3 0.001 to 0.2 Isopropanol (modifying agent) 0.01 to 10 0.25 to 8 1.5 to 6.3

The weight ratio of ethanol in the second residue to ethanol in the second distillate is preferably at least 3: 1, for example 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, for example less than 0.2: 1 or less than 0.1: 1. In an embodiment using an extraction column using 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. Therefore, as shown in Table 4, the second distillate of line 120, which is a derivative stream of the crude ethanol product, comprises a significant amount of denaturant separated in situ, and the second residue of line 118 is a substantial amount of ethanol. It includes. In some embodiments, the second distillate comprises diethyl ether. Diethyl ether may be present in an amount of 0.1% to 20% by weight, for example 0.1% to 10%, 1% to 9% or 3% to 7% by weight. In these cases, the second distillate can be a modified ethanol composition with diethyl ether modifier. In one embodiment, the second residue of line 118 further comprises isopropanol. Isopropanol can be derived from acetone through the methods discussed above. Acetone can be prepared, for example, in situ in hydrogenation and / or acetone can be added as a reactant to the hydrogenation reactor. Thus, in embodiments in which a sufficient amount, for example 0.1% to 10%, 1% to 9% or 3% to 7% by weight of isopropanol is present in the second residue, the second residue is It may be a modified ethanol composition having an isopropanol modifier.

In another embodiment of the present invention shown in FIG. 1A, at least a portion of the second distillate is directed to purified ethanol exiting third column 109, such as via line 120. In this case, the modified ethanol composition is produced by adding the denaturant prepared in situ to purified ethanol. Preferably, the ethyl acetate modifier of the second distillate is combined with the purified ethanol obtained from the third column 109. In another embodiment, the acetaldehyde modifier of the second distillate is combined with purified ethanol obtained from the third column 109. In another embodiment, at least a portion of the second distillate is fed to the third column 109. In these cases, at least a portion of the denaturant, such as ethyl acetate and / or acetaldehyde, in the second distillate follows the ethanol through the third column 109. Other impurities of the second distillate may be recovered in the residue of the third column 109. As a result, the third distillate contains ethanol together with the denaturant from the second column distillate. The modified ethanol composition thus formed may have the characteristics and composition of the modified ethanol composition discussed herein. The weight ratio of denaturant-containing stream, such as line 120 and purified ethanol stream, varies widely and can be adjusted to achieve the desired specific concentration of denaturant in the modified ethanol composition. For example, when ethyl acetate is the denaturant, the weight ratio of purified ethanol stream to denaturant-containing stream may be from 100: 1 to 1: 1, for example 25: 1 to 5: 1.

In other embodiments, at least a portion of the second distillate is recycled to reactor 103 (not shown). As a result, a second residue from the bottom of the second column 108, which includes ethanol and water, is fed via line 118 to a third column 109, also referred to as a "product column." More preferably, a second residue of line 118 is introduced into the bottom of third column 109, for example the bottom half or bottom third. The third column 109 recovers ethanol as the distillate of line 119, which is preferably substantially pure except for the azeotropic water content. The distillate of the third column 109 is preferably at a reflux ratio of, for example, 1:10 to 10: 1, for example 1: 3 to 3: 1 or 1: 2 to 2: 1, as shown in FIG. 1A. Reflux. The third residue of line 121, which preferably comprises mainly water, may preferably be removed from system 100 or partially returned to any part of system 100. The third column 109 is preferably a tray column as described above and is preferably operated at atmospheric pressure. The temperature of the third distillate leaving line 119 from the third column 109 is preferably 60 ° C. to 110 ° C., for example 70 ° C. to 100 ° C. or 75 ° C. to 95 ° C. The temperature of the third residue leaving the third column 109 is preferably 70 ° C. to 115 ° C., such as 80 ° C. to 110 ° C. or 85 ° C. to 105 ° C., when the column is operated at atmospheric pressure. Exemplary components of the distillate, residue and optional side flow composition of the third column 109 are provided in Table 5 below. As shown in Table 5, the third distillate may comprise a significant amount of isopropanol modifier. In this case, the third distillate may be a modified ethanol composition. It should be appreciated that distillates and residues may also contain other components not listed, such as components in the feed.

Since separation occurs in the third column, the composition of the stream being separated can vary from tray to tray in the third column. In some embodiments, the composition of the stream in the third column has a boiling point which is lower than the boiling point of an increased concentration of alcohol or accumulated alcohol, for example water, and higher than that of the ethanol / water low boiling azeotropic mixture, depending on the operating conditions. May contain medium-boiling alcohols. Examples of such alcohols include n-propanol (boiling point 97.1 ° C.), isopropanol (boiling point 82.5 ° C.) and 2-butanol (boiling point 99.5 ° C.). Some of these alcohols were produced in situ as a result of hydrogen acetate. Preferably, the medium-boiling alcohols produced in these in situ can be used as denaturant.

One or more side streams 138 withdrawing from the third column 109 may be used to remove the middle-boiling alcohol. Preferably, the side flow 138 is withdrawn from the middle zone or top zone of the third column 109 above the feed point of the second residue. Most preferably, side flow 138 is withdrawn from tray 25, for example from tray 30 or from tray 40. By adjusting the process parameters of the third column 109 and recovering the side flow 138 at the appropriate location, the side flow 138 frees a significant amount of medium-boiling alcohol, such as n-propanol, from the feed of line 118. Remove it. The side flow 138 preferably comprises 0.01 wt% to 10 wt%, such as 0.01 to 5 wt% or 0.01 wt% to 3 wt% n-propanol. By recovering the side stream 138, a significant amount of n-propanol is removed to purify the ethanol of the third distillate in line 119. It is within the scope of the present invention to select an appropriate tray of columns to withdraw a particular side flow based on the column configuration and operating conditions. In addition, the contents of side stream 138 may constitute a modified ethanol composition comprising ethanol and n-propanol. Thus, in this embodiment, the pure ethanol composition can be produced simultaneously with the modified ethanol composition. In other embodiments, the side stream 138 and the third distillate are each modified ethanol compositions independently of each other. For example, side flow 130 may comprise an n-propanol-modified ethanol composition and third distillate 119 may comprise an ethyl acetate-modified ethanol composition. By performing the separation in this way, the resulting third distillate 119 advantageously contains less n-propanol. In another embodiment, at least a portion of the recovered side stream 138 is combined with the third distillate 119 to produce a modified ethanol composition comprising at least a portion of the denaturant prepared in situ from the side stream 130. Can be.

Third column Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) Distillate ethanol 75 to 96 80 to 96 85 to 96 water <12 1 to 9 3 to 8 Acetic acid <1 0.001 to 0.1 0.005 to 0.01 Ethyl acetate <5 0.001 to 4 0.01 to 3 Isopropanol 0.07 to 10 0.8 to 7 2.5 to 7 Residue water 75 to 100 80 to 100 90 to 100 ethanol <0.8 0.001 to 0.5 0.005 to 0.05 Ethyl acetate <1 0.001 to 0.5 0.005 to 0.2 Acetic acid <2 0.001 to 0.5 0.005 to 0.2 Sidestream (optional) ethanol 0.01 to 10 0.01 to 5 0.01 to 3 n-propanol 0.1 to 10 0.25 to 8 1.5 to 6.3

Any compound carried through the distillation process from the feed or crude reaction product is generally in an amount of less than 0.1% by weight, for example less than 0.05% or less than 0.02% by weight, based on the total weight of the third distillate composition. Remains in the third distillate. In one embodiment, one or more side streams may remove impurities from any column 107, 108 and / or 109 of system 100. In one embodiment, one or more side streams may be used to remove impurities from the third column 109. Impurities may be purged and / or retained in the system 100.

Further purification of the third distillate of line 119, for example using one or more additional separation systems such as a distillation column (eg, finishing column) or molecular sieves, results in an anhydrous ethanol product stream, Absolute ethanol ".

Returning to the second column 108, the distillate of line 120 is preferably, for example, 1:10 to 10: 1, for example 1: 5 to 5, as shown in FIGS. 1A, 1B and 1C. It is refluxed at a reflux ratio of 1: 1 or 1: 3 to 3: 1. As indicated above, the second distillate comprises a significant amount of denaturant, for example ethyl acetate and / or acetaldehyde. Thus, all or a portion of the second distillate, shown in line 120, may be directed downstream, and may be combined with, for example, further purified ethanol through third column 109. In addition, at least some of the distillate from the second column 108 may be purged if necessary. In another embodiment, as shown in FIG. 1B, a portion of the second distillate from the second column 108 is recycled via line 120 to the reaction zone 101 to convert ethyl acetate to additional ethanol. You can. For example, it can be recycled to reactor 103 and fed simultaneously with acetic acid feed line 105. In other embodiments, one or more additional columns (not shown) may be used to further purify the second distillate of line 120 to remove other components, such as acetaldehyde. Specification 35 or 35-A of Part 21, Title 27 (hereinafter abbreviated as 27 CFR Part 21) of the US Federal Regulations where the denaturing agent of interest consists essentially of ethyl acetate (for example, incorporated herein by reference) ], Such a configuration can be used. Alternatively, an additional column (not shown) can be used to remove ethyl acetate and leave acetaldehyde, which can be useful in situations where the desired denaturant includes acetaldehyde and no ethyl acetate.

The system 100 of FIG. 1C is similar to the system of FIGS. 1A and 1B, in which the second distillate of line 120 is fed to a fourth column 123, also referred to as an “acetaldehyde removal column”. do. In a 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 to 20: 1, such as 1:10 to 10: 1 or 1: 5 to 5: 1, and at least a portion of the fourth distillate to line 124 As indicated, it may be returned to the reaction zone 101. For example, the fourth distillate can be combined with the acetic acid feed, added to the vaporizer 110, or added directly to the reactor 103. As shown, the fourth distillate is fed to the vaporizer 110 together with the acetic acid of the feed line 105. Without being bound by a particular theory, recycling acetaldehyde-containing streams to the reaction zone increases the yield of ethanol and reduces by-products and waste generation, since acetaldehyde can be hydrogenated to produce ethanol. In another embodiment (not shown), acetaldehyde is collected and used with or without further purification to include n-butanol, 1,3-butanediol and / or crotonaldehyde and derivatives, Useful products can be prepared that are not limited to these. In one preferred embodiment, acetaldehyde is removed from the second distillate of the fourth column 123 such that no detectable amount of acetaldehyde is present in the residue of the column 123.

In a preferred embodiment, the modified ethanol composition is prepared by combining at least a portion of the fourth distillate with a purified ethanol stream (not shown). Preferably, the denaturant comprises acetaldehyde and / or ethyl acetate. In other embodiments, at least a portion of the fourth distillate may be fed to the third column 109. As a result, in these embodiments, the distillate exiting the third column 109 may comprise at least a portion of acetaldehyde and / or ethyl acetate prepared in situ present in the fourth distillate. In these embodiments, the weight percent of acetaldehyde modifier in the modified ethanol composition may be as discussed above. The weight ratio of the purified ethanol stream to the fourth distillate can vary widely and can be adjusted to achieve the desired specific concentration of denaturant in the modified ethanol composition. For example, the weight ratio of purified ethanol stream to fourth distillate can be from 2: 1 to 75: 1, such as 7: 1 to 50: 1.

The fourth residue mainly contains ethyl acetate and ethanol. Preferably, at least a portion of the fourth residue is combined with the purified ethanol stream to produce a modified ethanol composition. Preferably, the denaturant comprises ethyl acetate. In other embodiments, at least a portion of the fourth residue may be fed to the third column 109. As a result, in these embodiments, the distillate leaving the third column 109 may comprise at least a portion of the ethyl acetate prepared in situ that was present in the fourth residue. In these embodiments, the weight percent of ethyl acetate modifier in the modified ethanol composition may be as discussed above. The weight ratio of the purified ethanol stream to the fourth residue can vary widely and can be adjusted to achieve the desired specific concentration of denaturant in the modified ethanol composition. For example, the weight ratio of purified ethanol stream to fourth residue may be 1: 1 to 50: 1, for example 1.75: 1 to 20: 1. In other embodiments, the fourth residue of fourth column 123 may be purged through line 125.

The fourth column 123 is preferably a tray column as described above and is preferably operated at pressures above atmospheric pressure. In one embodiment, the pressure is 120 KPa to 5,000 KPa, for example 200 KPa to 4,500 KPa, or 400 KPa to 3,000 KPa. In a preferred embodiment, the fourth column 123 can be operated at a higher pressure than the pressure of other columns.

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

Fourth column Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) Distillate Acetaldehyde 2 to 80 2 to 50 5 to 40 Ethyl acetate <90 30 to 80 40 to 75 ethanol <30 0.001 to 25 0.01 to 20 water <25 0.001 to 20 0.01 to 15 Residue Ethyl acetate 40 to 100 50 to 100 60 to 100 ethanol <40 0.001 to 30 0.01 to 15 water <25 0.001 to 20 2 to 15 Acetaldehyde <1 0.001 to 0.5 Undetectable Acetal <3 0.001 to 2 0.01 to 1

1C also shows that the third residue of line 121 can be recycled to the second column 108. In one embodiment, recycling of the third residue further reduces the aldehyde component in the second residue and concentrates these aldehyde components in the distillate stream 120 to the fourth column 123, where the fourth In the column 123, the aldehyde can be more easily separated. This embodiment also provides a finished ethanol product, preferably with small amounts of aldehydes and esters.

In some embodiments, the denaturant-containing stream is combined with a purified ethanol stream to produce a modified ethanol composition. In other embodiments, these denaturant-containing streams may be fed to the third column 109 as opposed to combining with the distillate of the third column 109. In these cases, the denaturant supplied to the column 109 can be separated from the distillate of the third column 109 and thus present in purified ethanol. Therefore, the third distillate may comprise a modified ethanol composition.

As indicated above, the modified ethanol composition obtained by the method of the present invention comprises ethanol and one or more, for example two or more or three or more modifier (s). The hydrogenation reaction produces a denaturant in situ, eliminating the need for an external denaturant source. Preferably, the denaturant comprises ethyl acetate, acetaldehyde, diethyl ether, acetic acid, isopropanol and / or mixtures thereof.

The denaturant so produced should be present in an effective amount, for example in an amount sufficient to provide a modified ethanol composition according to appropriate government regulations. As used herein, the term “modified ethanol composition” refers to a composition comprising ethanol and one or more denaturing agents that are not suitable, for example, not suitable for use as beverages or human oral medicines. In other embodiments, the modified ethanol is 27 C.F.R. Part 21, subpart D, may include “specially modified ethanol”, an ethanol composition that is modified according to the specifications applied under subpart D. In addition, the conditions for the modified ethanol are different in different uses, for example fuel use and industrial use. Therefore, some applications may require higher amounts of denaturant, while others may require smaller amounts of denaturant. A list of some of these uses is incorporated by reference in C.F.R. It is provided in Part 21. Table 7 shows some of the denaturing compositions in terms of the amount of denaturing agent added to 100 gallons of ethanol.

27 C.F.R. U.S. modified alcohol standard according to part 21 standard Denaturant Volume (gallons) Specification 3-C Isopropyl Alcohol 5 Specification 13-A Ethyl ether 10 Size 18 ^* Acetic Acid Pharmaceutical 90-Grain Strength (9% Acetic Acid in Water) 100 Size 18 ^* Acetic acid pharmaceutical 60-grain strength (6% acetic acid in water) 150 Specification 29 Acetaldehyde One Specification 29 Alcohol solution containing 20% or more acetaldehyde 5 Specification 29 Ethyl acetate One Specification 32 Ethyl ether 5 Specification 35 Ethyl acetate 29.75 Specification 35 Mixtures of ethyl acetate having an ester content of at least 85% by weight 35 Specification 35-A Ethyl acetate 4.25 Specification 35-A Mixtures of ethyl acetate having an ester content of at least 85% by weight 5 ^* Ethanol is more than 160 degrees proof.

In another embodiment, the modified ethanol composition of the present invention as it is produced corresponds to the modification standard of a country other than the United States. For example, in the UK, one specification for product specific modified alcohols is as follows. Alcohol (strength of alcohol at least 85% by volume) For every 979 parts, at least 20 parts of ethyl acetate and 1 part of isopropyl alcohol are mixed.

Other exemplary British product specific modified alcohol specifications are as follows. Alcohol (strength at least 85% by volume alcohol) Mix at least 50 parts of isopropyl alcohol every 950 parts by volume.

Of course, this list of US and international modified ethanol composition specifications is not exclusive, and other specifications are clearly within the scope of the present invention.

Preferably, the modified ethanol composition comprises 50% to 99% by weight, such as 60% to 99% by weight, or 70% to 95% by weight of ethanol and 0.01% by weight, based on the total weight of the modified ethanol composition. To 40% by weight, for example 0.01% to 25% by weight, 0.01% to 20% by weight, or 1% to 15% by weight of modifier.

In addition to ethanol and denaturant, the modified ethanol composition also contains acetic acid; C ₃ alcohols such as n-propanol and isopropanol; And / or other impurities such as C ₄ -C ₅ alcohols only in trace amounts.

In some embodiments, the modified ethanol composition of the present invention comprises at least a portion of the first column distillate as discussed above. Here, the modified ethanol composition may include ethyl acetate and / or acetaldehyde as the modifying agent. Exemplary weight percent ranges of ethanol and denaturant (as well as other optional ingredients) are provided in Table 3 above. Preferably, the amount of total modifiers (ethyl acetate and acetaldehyde) in these modified ethanol compositions is from 0.01% to 90% by weight, for example from 0.01% to 65% or from 0.01% to 34% by weight.

In another embodiment, the modified ethanol composition is recovered from the separation tower in the separation zone. In these cases, the ethanol composition may include, for example, an isopropanol modifier in an amount of 0.1% to 10% by weight, for example 1% to 9% by weight or 3% to 7% by weight.

In other embodiments, the ethanol composition comprises 0.1 wt% to 20 wt%, such as 0.1 wt% to 10 wt%, 1 wt% to 9 wt%, or 3 wt% of ethyl ether, eg, diethyl ether modifier. In an amount of 7% by weight. In other embodiments, the ethanol composition comprises acetic acid modifier in an amount of 0.1% to 20% by weight, such as 1% to 15% or 2% to 12% by weight. In other embodiments, the ethanol composition comprises from 0.001% to 10% by weight, such as from 0.001% to 0.1%, from 0.1% to 10%, from 1% to 9% or 3% by weight of n-propanol modifier. In an amount of 7% by weight.

In a preferred embodiment, the modified ethanol composition is produced by combining a crude ethanol product derivative stream comprising a denaturant, for example a second distillate, with a purified ethanol stream. Exemplary weight percent ranges of ethanol and modifiers such as ethyl acetate and / or acetaldehyde (and other optional ingredients) are provided in Table 8. In some embodiments, the ethanol composition comprises ethyl acetate modifier in an amount of 0.01 wt% to 40 wt%, for example 0.01 wt% to 15 wt%, 0.01 wt% to 10 wt%, or 0.01 wt% to 9 wt%. do. In other embodiments, the ethanol composition comprises acetaldehyde modifier in an amount of 0.01% to 10% by weight, such as 0.01% to 5%, 0.01% to 2%, or 0.01% to 1% by weight. Preferably, the amount of total modifier in these modified ethanol compositions is from 0.01% to 20% by weight, such as from 0.01% to 12% by weight or from 0.01% to 10% by weight.

Modified Ethanol Composition ingredient Concentration (% by weight) Concentration (% by weight) Concentration (% by weight) ethanol 50 to 99 60 to 99 70 to 95 water 0.0001 to 1 0.001 to 0.1 0.001 to 0.05 Acetic acid 1 to 20 3 to 15 5 to 10.5 Ethyl acetate (modifier) <15 <10 <9 Acetaldehyde (modifier) <10 <5 <3 Isopropanol (modifying agent) 0.05 to 10 0.6 to 9 2 to 6.7 Diethyl ether (modifier) 0.05 to 10 0.6 to 9 2 to 6.7 n-propanol (modifier) 0.05 to 10 0.6 to 9 2 to 6.7 Acetal <0.05 <0.01 <0.005 Acetone <0.05 <0.01 <0.005

Although exemplary weight percent of water in the embodiments of Table 8 is from 0.0001% to 1% by weight, in other embodiments water may be present in the modified ethanol composition in higher amounts. For example, the modified ethanol composition may comprise water in an amount of 0.1 wt% to 8 wt%, such as 0.1 wt% to 5 wt% or 0.1 wt% to 2 wt%.

Modified ethanol compositions of embodiments of the present invention may be suitable for use in a variety of applications, including fuels, solvents, chemical feedstocks, pharmaceutical products, detergents, sanitizers, hydrogenation vehicles, or consumption agents. In fuel applications, the modified ethanol composition can be blended with gasoline for transportation vehicles such as automobiles, boats and small piston engine airplanes. In non-fuel applications, the modified ethanol compositions can be used as toiletry and cosmetic preparations, detergents, disinfectants, coatings, inks and solvents for pharmaceuticals. The modified ethanol composition may also be used as a processing solvent, for example in the manufacture of pharmaceutical products, foodstuffs, dyes, photochemicals and latex processing agents.

The modified ethanol composition can also be used as a chemical feedstock to prepare other chemicals such as acetic acid agent, ethyl acrylate, ethyl acetate, ethylene, glycol ether, ethylamine, aldehyde and higher alcohols, especially butanol. The modified ethanol composition may be suitable for use as feedstock in ester preparation. Preferably, in the production of ethyl acetate, the modified ethanol composition can be esterified with acetic acid or reacted with polyvinyl acetate. The modified ethanol composition may be dehydrated to produce ethylene. Ethanol may be dehydrated using any known dehydration catalyst, such as described in US Patent Publication Nos. 2010/0030001 and 2010/0030002, which are incorporated herein by reference. For example, a zeolite catalyst can be used as the dehydration catalyst. Preferably, the zeolite has a pore diameter of about 0.6 nm or more, and the preferred zeolite includes a dehydration catalyst selected from the group consisting of mordenite, ZSM-5, zeolite X and zeolite Y. Zeolite X is described, for example, in US Pat. No. 2,882,244 and Zeolite Y is disclosed in US Pat. No. 3,130,007, which is incorporated herein by reference.

In order to more effectively understand the invention disclosed herein, some non-limiting examples are provided below. The following examples describe various embodiments of the ethanol compositions of the present invention.

Example

Example  One

A vaporized feed comprising 95.2 wt% acetic acid and 4.6 wt% water was prepared in the presence of a catalyst comprising 1.6 wt% platinum and 1 wt% tin supported on a 1/8 inch calcium silicate modified silica extrudate, Reaction with hydrogen at an average temperature of 291 ° C. and an outlet pressure of 2,063 KPa yielded a crude ethanol product comprising ethanol, acetic acid, water and ethyl acetate. Unreacted hydrogen was recycled back to the reactor inlet so that the total hydrogen / acetic acid molar ratio was 5.8 at a GHSV of 3,893 hours ⁻¹ . Under these conditions, 42.8% of acetic acid was converted, 87.1% for ethanol, 8.4% for ethyl acetate, and 3.5% for acetaldehyde. The crude ethanol mixture was purified using a separation scheme with a distillation column shown in FIG. 1A.

The crude ethanol product was fed to the first column at a feed rate of 20 g / min. The composition of the liquid feed is provided in Table 8. The first column was Oldershaw, 2 inches in diameter with 50 trays. The column was operated at a temperature of 115 ° C. and atmospheric pressure. Unless otherwise indicated, the column operating temperature is the temperature of the liquid in the reboiler and the pressure at the top of the column is atmospheric (about 1 atmosphere). The column differential pressure between the trays in the first column was 7.4 KPa. The first residue was recovered at a flow rate of 12.4 g / min and returned to the hydrogenation reactor.

The first distillate was condensed at the top of the first column and refluxed at a ratio of 1: 1, then a portion of the distillate was introduced into the second column at a feed rate of 7.6 g / min. The second column was an 2 inch diameter Aldershaw design with 25 trays. The second column was operated at 82 ° C. and atmospheric pressure. In this embodiment, no extractant was used. The column differential pressure between the trays in the second column was 2.6 KPa. The second residue was recovered at a flow rate of 5.8 g / min and sent to the third column. The second distillate was refluxed at a ratio of 4.5: 0.5 and the remaining distillate was collected for analysis. The composition of the feeds, distillates and residues is provided in Table 9.

First column Second column ingredient Feed
(weight%) Distillate
(weight%) Residue
(weight%) Distillate
(weight%) Residue
(weight%) water 13.8 24.7 5.6 5.1 30.8 Acetaldehyde - 1.8 - 8.3 - Acetic acid 55.0 0.08 93.8 0.03 0.1 ethanol 23.4 57.6 0.06 12.4 67.6 Ethyl acetate 6.5 15.1 - 76.0 - Acetal 0.7 0.1 - 0.006 0.03 Acetone - 0.01 - 0.03 -

As shown in Table 9, the first column distillate is a modified ethanol composition comprising ethanol and a modifier produced in substantial in situ.

Residues of the second column were collected from several runs and introduced into the third column (2 inch Aldershow containing 60 trays) at 10 g / min (above tray 25). The third column was operated at 103 ° C. and atmospheric pressure. The column differential pressure between the trays in the third column was 6.2 KPa. The third residue was recovered at a flow rate of 2.7 g / min. The third distillate was condensed at the top of the third column and refluxed at a ratio of 3: 1. The composition of the recovered ethanol composition is shown in Table 10. The ethanol composition comprises ethanol and a significant amount of ethyl acetate prepared in situ. This modified ethanol composition was surprisingly and unexpectedly a modified ethanol composition prepared without the addition of an external denaturant. The ethanol composition also contained 10 ppm of n-butyl acetate.

Third column ingredient Feed (% by weight) Distillate (wt%) Residue (% by weight) Acetic acid 0.098 0.001 0.4 ethanol 65.7 93.8 0.004 water 35.5 6.84 98 Ethyl acetate 1.37 1.8 - Acetal 0.02 0.03 - Isopropanol 0.004 0.005 - n-propanol 0.01 0 -

Example  2

A vaporized feed comprising 96.3 wt% acetic acid and 4.3 wt% water was prepared in the presence of a catalyst comprising 1.6 wt% platinum and 1 wt% tin supported on a 1/8 inch calcium silicate modified silica extrudate, Reaction with hydrogen at an average temperature of 290 ° C. and an outlet pressure of 2,049 KPa yielded a crude ethanol product comprising ethanol, acetic acid, water and ethyl acetate. Unreacted hydrogen was recycled back to the reactor inlet so that the total hydrogen / acetic acid molar ratio was 10.2 at a GHSV of 1,997 h ⁻¹ . Under these conditions, 74.5% of acetic acid was converted, with 87.9% selectivity for ethanol, 9.5% selectivity for ethyl acetate, and 1.8% selectivity for acetaldehyde. The crude ethanol mixture was purified using a separation scheme with a distillation column shown in FIG. 1A.

The crude ethanol product was fed to the first column at a feed rate of 20 g / min. The composition of the liquid feed is provided in Table 11. The first column was an alder show of 2 inches in diameter with 50 trays. The column was operated at a temperature of 116 ° C. and atmospheric pressure. The column differential pressure between the trays in the first column was 8.1 KPa. The first residue was recovered at a flow rate of 10.7 g / min and returned to the hydrogenation reactor.

The first distillate was condensed at the top of the first column and refluxed at a ratio of 1: 1, then a portion of the distillate was introduced into the second column at a feed rate of 9.2 g / min. The second column is an 2 inch diameter Aldershow design with 25 trays. The second column was operated at 82 ° C. and atmospheric pressure. The column differential pressure between the trays in the second column was 2.4 KPa. The second residue was recovered at a flow rate of 7.1 g / min and sent to the third column. The second distillate was refluxed at a ratio of 4.5: 0.5 and the remaining distillate was collected for analysis. The compositions of the feeds, distillates and residues are provided in Table 11.

First column Second column ingredient Feed
(weight%) Distillate
(weight%) Residue
(weight%) Distillate
(weight%) Residue
(weight%) water 14.6 27.2 3.7 3.0 36.2 Acetaldehyde - 1.5 - 10.3 - Acetic acid 49.1 0.2 98.2 0.04 0.3 ethanol 27.6 54.5 0.04 13.3 64.4 Ethyl acetate 7.9 15.2 - 75.7 1.8 Acetal 0.7 0.1 - 0.01 0.02 Acetone - 0.01 - 0.03 -

As shown in Table 11, the first column distillate is a modified ethanol composition comprising ethanol and a significant amount of denaturant produced in situ.

Example  3

A vaporized feed comprising 98% by weight acetic acid and 2% by weight acetone, in the presence of a catalyst comprising 1.6% by weight of platinum and 1% by weight of tin supported on a 1/8 inch calcium silicate modified silica extrudate, Reaction with hydrogen at an average temperature of 291 ° C. and an outlet pressure of 1,420 KPa yielded a crude ethanol product comprising ethanol, isopropanol, acetic acid, water and ethyl acetate. The catalyst was diluted to a volume ratio of 1: 1 with 3 mm glass beads. Under these conditions, the acetone conversion was 68% and the resulting ethanol / isopropanol mixture after separation contained 4.3% by weight of isopropanol.

The composition of the resulting crude ethanol composition is provided in Table 12.

ingredient weight% ethanol 30.7 Acetaldehyde 0.3 Acetone 0.6 Isopropanol 1.3 Ethyl acetate 3.4 Acetic acid 50.9 Acetal 0.5

As shown in Table 12, addition of acetone to the acetic acid feed produces isopropanol when the acetic acid feed is hydrogenated. The crude ethanol product prepared from hydrogenation provides a modified ethanol composition comprising ethanol and 4.3% by weight of isopropanol produced in situ.

In another embodiment, a modified ethanol composition is produced by combining a crude ethanol product derivative stream comprising a denaturant with a purified ethanol stream. This combines the denaturant from the derivative stream with the purified ethanol stream.

Example  4

Through acetic acid hydrogenation as discussed above, a crude ethanol product was prepared comprising ethanol, acetic acid, acetaldehyde, water and ethyl acetate. The crude ethanol product was purified using a separation scheme with a distillation column shown in FIG. 1A. The second column was operated as an extractive distillation column using a water extractant.

The composition of the distillate leaving the second column and the distillate leaving the third column is provided in Table 13.

ingredient Second distillate (% by weight) Third distillate (% by weight) ethanol 12.4 93.8 Ethyl acetate 76 1.8 Acetaldehyde 8.3 0 Acetic acid 0.03 0.001 Isopropanol 0 0.005 n-propanol 0 0 Acetone 0.03 0 Acetal 0.006 0.03 water 5.1 6.8

The second and third distillates of Table 13 provide the modified ethanol compositions described in Table 14 when mixed in a weight ratio of 1.6: 1 and 21: 1, respectively.

1.6: 1 weight ratio 21: 1 weight ratio ingredient weight% weight% ethanol 61 88 Ethyl acetate 30 5 Acetaldehyde 3 0.4 Acetic acid 0.01 0.002 Isopropanol 0.003 0.005 n-propanol 0 0 Acetone 0.01 0.001 Acetal 0.02 0.03 water 6 7

Example  5

Through acetic acid hydrogenation as discussed above, a crude ethanol product was prepared comprising ethanol, acetic acid, acetaldehyde, water and ethyl acetate. The crude ethanol product was purified using a separation scheme with a distillation column shown in FIG. 1C.

The composition of the residue leaving the fourth column and the distillate leaving the third column is shown in Table 15.

ingredient 4th residue (% by weight) Third distillate (% by weight) ethanol 14.3 93.8 Ethyl acetate 80.5 1.8 Acetaldehyde - 0 Acetic acid 0.03 0.001 Isopropanol - 0.005 n-propanol - 0 Acetone 0.01 0 Acetal 0.017 0.03 water 4.7 6.8

Combined in a weight ratio of 1.75: 1 and 20: 1, respectively, the third distillate and the fourth residue of Table 15 provide the modified ethanol compositions described in Table 16.

1.75: 1 weight ratio 20: 1 weight ratio ingredient weight% weight% ethanol 64 88 Ethyl acetate 30 5 Acetaldehyde 0 0 Acetic acid 0.01 0.002 Isopropanol 0.003 0.005 n-propanol 0 0 Acetone 0 0.0005 Acetal 0.02 0.03 water 6 7

Example  6

Through acetic acid hydrogenation as discussed above, a crude ethanol product was prepared comprising ethanol, acetic acid, acetaldehyde, water and ethyl acetate. The crude ethanol product was purified using a separation scheme with a distillation column shown in FIG. 1C.

The composition of the distillate leaving the fourth column and the distillate leaving the third column is shown in Table 17.

ingredient Fourth distillate (% by weight) Third distillate (% by weight) ethanol 5.4 93.8 Ethyl acetate 39.8 1.8 Acetaldehyde 61.5 0 Acetic acid 0.02 0.001 Isopropanol - 0.005 n-propanol - 0 Acetone 0.08 0 Acetal 0.001 0.03 water 2.1 6.8

When combined in a weight ratio of 7: 1 and 50: 1, respectively, the third and fourth distillates of Table 17 provide the modified ethanol compositions described in Table 18.

7: 1 weight ratio 50: 1 weight ratio ingredient weight% weight% ethanol 80 90 Ethyl acetate 6 2 Acetaldehyde 7 One Acetic acid 0 0.001 Isopropanol 0.004 0.005 n-propanol 0 0 Acetone 0.01 0.0015 Acetal 0.03 0.03 water 6 7

Example  7

Through acetic acid hydrogenation as discussed above, a crude ethanol product was prepared comprising ethanol, acetic acid, acetaldehyde, water and ethyl acetate. The crude ethanol product was purified using a separation scheme with a distillation column shown in FIG. 1C.

The composition of the distillate leaving the first column and the distillate leaving the third column is shown in Table 19.

ingredient First distillate (% by weight) Third distillate (% by weight) ethanol 57.6 93.8 Ethyl acetate 15.1 1.8 Acetaldehyde 1.8 0 Acetic acid 0.08 0.001 Isopropanol - 0.005 n-propanol - 0 Acetone 0.01 0 Acetal 0.1 0.03 water 24.7 6.8

Combined in a weight ratio of 0.05: 1 and 3: 1, respectively, the third and first distillates of Table 19 provide the modified ethanol compositions described in Table 20.

0.05: 1 weight ratio 3: 1 weight ratio ingredient weight% weight% ethanol 60 83 Ethyl acetate 15 5 Acetaldehyde 2 0 Acetic acid 0.08 0.02 Isopropanol 0 0.004 n-propanol 0 0 Acetone 0.01 0.0025 Acetal 0.1 0.05 water 24 11

Example  8

Through the acetic acid hydrogenation discussed above, a crude ethanol product was prepared comprising ethanol, acetic acid, acetaldehyde, water and ethyl acetate. The first column can be used to purify the crude ethanol product. In this separation scheme, however, the first distillate can be sent directly to the third column to bypass the second and / or fourth column. The third column can provide residue and distillate. The compositions of the first and third distillates are provided in Table 24. The third distillate is a modified ethanol composition which can be advantageously prepared without the need for a second column or fourth column.

ingredient First distillate (% by weight) Third distillate (% by weight) ethanol 57.6 77 Ethyl acetate 15.1 20 Acetaldehyde 1.8 2 Acetic acid 0.08 0 Isopropanol - 0 n-propanol - 0 Acetone 0.01 0.01 Acetal 0.1 0.13 water 24.7 0

Example  9

Through the acetic acid hydrogenation discussed above, a crude ethanol product was prepared comprising ethanol, acetic acid, acetaldehyde, water and ethyl acetate. In particular, the crude ethanol product was purified using a separation scheme having a first distillation column and a second distillation column shown in FIG.

Residue from the second column was collected from several runs and introduced into the third column (2 inch Aldershow with 50 trays) at a rate of 18 g / min. The third column was operated at a temperature of 102 ° C. and atmospheric pressure. The column differential pressure between the trays in the third column was 6.2 KPa. The third residue was recovered at a flow rate of 13 g / min. The third distillate was condensed at the top of the third column and refluxed at a ratio of 3: 2.

The composition of some of the components of the second residue at various tray locations in the third column is shown in FIG. 2. Ethanol is also present in significant amounts in each tray.

As shown in FIG. 2, the side flow can be recovered from the third column. Preferably the recovered side stream comprises ethanol and n-propanol. The side flow recovered from the third column provides a modified ethanol composition comprising ethanol and n-propanol. In some embodiments, the sidestream can be combined with a purified ethanol stream, eg, a third distillate, to form a separate modified ethanol composition. Each of these modified ethanol compositions can be prepared surprisingly and unexpectedly without the addition of external modifications.

In the sample of FIG. 2, the side flow is passed through trays 22-52, such as trays 25-43; Trays 25 to 40; Or from trays 26 to 39. However, the sample of FIG. 2 is illustrative only. It is within the scope of the present invention to obtain the desired sidestream composition by adjusting the point of recovery of the sidestream based on the process parameters.

While the invention has been described in detail, modifications within the spirit and scope of the invention will be apparent to those skilled in the art. In view of the foregoing discussion, the disclosures of related knowledge and references in the art described above in connection with the background and detailed description are all incorporated herein by reference. In addition, it should be understood that various embodiments may be combined or interchanged, in whole or in part, with various embodiments and aspects of the present invention and / or cited below and / or in the appended claims. In the above description of various embodiments, such embodiments representing another embodiment may be combined as appropriate with other embodiments, as will be appreciated by those skilled in the art. In addition, those skilled in the art will understand that the above description is examples only and does not limit the present invention.

Claims (46)

Hydrogenating the acetic acid feed in the presence of a catalyst to produce a crude ethanol product comprising ethanol and one or more modifiers;
Separating the crude ethanol product into a modified ethanol composition and one or more derivative streams in one or more separation units
As a method for producing a modified ethanol composition,
Wherein the modified ethanol composition comprises 0.01 wt% to 40 wt% modifier based on the total weight of the modified ethanol composition. The method of claim 1,
Wherein said at least one denaturing agent is selected from the group consisting of acetaldehyde, acetaldol, ethyl ether and methanol. The method according to claim 1 or 2,
Wherein said at least one denaturing agent comprises ethyl acetate. The method according to any one of claims 1 to 3,
Wherein said at least one denaturing agent comprises acetaldehyde. The method according to any one of claims 1 to 3,
Wherein said at least one denaturing agent comprises isopropanol. The method according to any one of claims 1 to 3,
Wherein said at least one denaturing agent comprises diethyl ether. The method according to any one of claims 1 to 3,
Wherein said at least one denaturing agent comprises acetic acid. The method according to any one of claims 1 to 3,
The modified ethanol composition comprises 50% to 99% by weight of ethanol. The method according to any one of claims 1 to 8,
Wherein the acetic acid feed comprises acetic acid and propionic acid. The method of claim 9,
The propionic acid is hydrogenated to produce n-propanol. 11. The method of claim 10,
This method,
Separating at least a portion of the crude ethanol product in a first column into a first distillate comprising ethanol and n-propanol and a first residue comprising acetic acid;
Separating at least a portion of the first distillate in a second column into a second residue comprising a second distillate and ethanol, at least a portion of n-propanol and water;
Separating at least a portion of the second residue in a third column into a third distillate comprising ethanol and a third residue comprising water
Further comprising, manufacturing method. The method of claim 11,
Wherein the method further comprises recovering a side stream comprising n-propanol from the third column. 13. The method according to any one of claims 1 to 12,
The crude ethanol product comprises 0.01 wt% to 20 wt% ethyl acetate, based on the total weight of the crude ethanol product; 0.01 wt% to 10 wt% acetaldehyde; 0.01 wt% to 10 wt% isopropanol; 0.01 wt% to 20 wt% diethyl ether; Acetic acid 0% to 90%; And 5% to 35% by weight of water. The method according to any one of claims 1 to 13,
Wherein the acetic acid feed comprises acetic acid and acetone and the at least one denaturing agent comprises isopropanol. The method according to any one of claims 1 to 14,
Wherein the method further comprises contacting acetic acid with hydrogen under conditions effective to produce acetone in a secondary reactor. The method according to any one of claims 1 to 14,
Comprising 0.1 to 10% by weight of isopropanol based on the total weight of the modified ethanol composition in the state where the modified ethanol composition is produced, manufacturing method. The method according to any one of claims 1 to 16,
Said separation,
Separating the first portion of the crude ethanol product into an ethanol stream and one or more derivative streams;
Purifying the ethanol stream to produce a purified ethanol stream;
A second portion of the crude ethanol product is combined with the purified ethanol stream to form a modified ethanol composition.
Including, manufacturing method. The method according to any one of claims 1 to 17,
Said separation,
Separating at least a portion of the crude ethanol product into an ethanol stream and one or more derivative streams;
Purifying the ethanol stream to produce a purified ethanol stream;
At least a portion of the acetic acid feed is combined with the purified ethanol stream to produce a modified ethanol composition.
Including, manufacturing method. The method according to any one of claims 1 to 18,
The method further comprises separating, in a first column, at least a portion of the crude ethanol product into a first distillate comprising ethanol, acetaldehyde and ethyl acetate and a first residue comprising acetic acid, Manufacturing method. The method according to any one of claims 1 to 19,
This method,
Separating at least a portion of the first distillate into an ethanol stream and a denaturant stream comprising acetaldehyde and ethyl acetate;
Purifying the ethanol stream to produce a purified ethanol stream;
At least a portion of the denaturant stream is combined with the purified ethanol stream to produce a modified ethanol composition
Further comprising, manufacturing method. The method according to any one of claims 1 to 19,
This method,
Separating at least a portion of the first distillate into an ethanol stream;
Purifying the ethanol stream to produce a purified ethanol stream;
At least a portion of the first residue and the purified ethanol stream are combined to form a modified ethanol composition
Further comprising, manufacturing method. The method according to any one of claims 1 to 19,
This method,
In a second column, separating at least a portion of the first distillate into an ethanol stream and a second distillate comprising ethyl acetate and / or acetaldehyde;
Purifying the ethanol stream to produce a purified ethanol stream;
Combining at least a portion of said second distillate with a purified ethanol stream to produce a modified ethanol composition
Further comprising, manufacturing method. The method of claim 22,
The second column is an extractive distillation column. The method according to any one of claims 1 to 19,
This method,
In a second column, separating at least a portion of the first distillate into an ethanol stream and a second residue comprising ethyl acetate;
Purifying the ethanol stream to produce a purified ethanol stream;
Combining at least a portion of said second residue with a purified ethanol stream to produce a modified ethanol composition
Further comprising, manufacturing method. 25. The method of claim 24,
Wherein said second column is a non-extracted distillation column. The method according to any one of claims 1 to 19,
This method,
In a second column, separating at least a portion of the first distillate into an ethanol stream and a second residue comprising ethyl acetate;
In a third column, separating at least a portion of the second residue into a third distillate comprising ethyl acetate and ethanol
Further comprising, manufacturing method. The method according to any one of claims 1 to 26,
The denaturing agent comprises ethyl acetate,
Wherein the modified ethanol composition further comprises 0.01 wt% to 40 wt% ethyl acetate, 50 wt% to 99 wt% ethanol, and 1 wt% to 35 wt% water, based on the total weight of the crude ethanol product. The method according to any one of claims 1 to 26,
The denaturing agent comprises acetaldehyde,
Wherein the modified ethanol composition further comprises 0.01% to 10% by weight acetaldehyde, 50% to 99% ethanol and 1% to 35% water by weight based on the total weight of the crude ethanol product. The method according to any one of claims 1 to 26,
The denaturing agent comprises isopropanol,
Wherein the modified ethanol composition further comprises 0.1% to 10% by weight isopropanol, 50% to 99% ethanol and 1% to 35% water by weight based on the total weight of the crude ethanol product. The method according to any one of claims 1 to 26,
The denaturing agent comprises diethyl ether,
Wherein the modified ethanol composition further comprises from 0.01% to 20% by weight of diethyl ether, from 50% to 99% by weight of ethanol and from 1% to 35% by weight of water, based on the total weight of the crude ethanol product, Manufacturing method. The method according to any one of claims 1 to 26,
The denaturing agent comprises acetic acid,
Wherein the modified ethanol composition further comprises 0.01% to 20% by weight acetic acid, 50% to 99% ethanol and 1% to 35% water by weight based on the total weight of the crude ethanol product. The method according to any one of claims 1 to 26,
The denaturing agent comprises n-propanol,
Wherein the modified ethanol composition further comprises 0.1% to 10% by weight of n-propanol, 50% to 99% by weight of ethanol and 1% to 35% by weight of water, based on the total weight of the crude ethanol product. . 33. A modified ethanol composition prepared by the method according to any one of claims 1 to 32. A fuel composition comprising the modified ethanol composition of claim 33. A feedstock for preparing an ester comprising the modified ethanol composition according to claim 33. A solvent comprising the modified ethanol composition according to claim 33. Hydrogenating the acetic acid feed in the presence of a catalyst to produce a crude ethanol product comprising ethanol and a denaturant;
Separating the crude ethanol product into one or more derivative streams comprising an ethanol stream and a denaturant;
Further purifying the ethanol stream to produce a purified ethanol stream;
At least a portion of the at least one derivative stream is combined with a purified ethanol stream to produce a modified ethanol composition
A method of producing a modified ethanol composition comprising a. 39. The method of claim 37,
The modified ethanol composition comprises 50 to 99% by weight of ethanol and 0.01 to 40% by weight modifier. 39. The method of claim 37,
The crude ethanol product comprises 5 wt% to 70 wt% of ethanol based on the total weight of the crude ethanol product; 0.01 wt% to 10 wt% acetaldehyde; 0.01 wt% to 10 wt% isopropanol; 0.01 wt% to 20 wt% diethyl ether; 0.01 wt% to 20 wt% ethyl acetate; Acetic acid 0% to 90%; And 5% to 35% by weight of water. 40. The method according to any one of claims 37 to 39,
Wherein said denaturing agent is selected from the group consisting of acetaldehyde, acetaldol, ethyl ether and methanol. 41. The method of any one of claims 37-40.
The modifier is ethyl acetate. 42. The compound of any one of claims 37-41,
This method,
In a first column, separating at least a portion of the crude ethanol product into a first distillate comprising ethanol and a denaturant and a first residue comprising acetic acid;
In a second column, separating at least a portion of the first distillate into a second distillate comprising a denaturant and a second residue comprising an ethanol stream;
In a third column, separating at least a portion of the ethanol stream into a third distillate comprising a purified ethanol stream and a third residue comprising water
Further comprising, manufacturing method. 43. The method of claim 42,
Wherein the method further comprises adding at least a portion of the second distillate to at least a portion of the purified ethanol stream to produce a modified ethanol composition. Hydrogenating the acetic acid feed comprising acetic acid and acetone in the presence of a catalyst to produce a crude ethanol product comprising ethanol and isopropanol;
Separating the crude ethanol product into a modified ethanol composition and one or more derivative streams in one or more separation units
As a method for producing a modified ethanol composition,
Comprising 0.1 to 10% by weight of isopropanol based on the total weight of the ethanol and the modified ethanol composition in the state where the modified ethanol composition is produced. 45. The method of claim 44,
The crude ethanol product comprises 5 wt% to 70 wt% of ethanol based on the total weight of the crude ethanol product; 0.01 wt% to 10 wt% acetaldehyde; 0.01 wt% to 10 wt% isopropanol; 0 wt% to 20 wt% ethyl acetate; And 5% to 35% by weight of water. A modified ethanol composition produced by the method according to any one of claims 37 to 45.

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