Process for the production of renewable aviation kerosene

Abstract

The present invention relates to a process for the production of renewable aviation kerosene (bioQAV) which involves the conversion of ethanol from a renewable source and optionally methanol, CO2, syngas or mixtures thereof to a stream of hydrocarbons in the range of aviation kerosene. The stream has predominantly alkylaromatics and can be used as a partial component of aviation kerosene, which can be fully or partially hydrogenated to alkylcycloalkanes.

Description

Technical Field

[0001] This invention relates to a method for producing renewable aviation kerosene (bioQAV) from ethanol produced by fermentation of sugar used in the fields of biofuels and renewable energy, which aims to convert ethanol into at least 50% C8+. Background Technology

[0002] Currently, there is a need in this field for biofuels, especially renewable aviation kerosene (bioQAV), to replace fossil fuels.

[0003] The primary route considered in this field for obtaining bioQAV is the hydroprocessing of vegetable oils (HVO) to produce alkanes, which are then hydroisomerized for use as jet fuel (QAV). However, biodiesel production using the same raw materials already exists, limiting its availability. Furthermore, the chain size of alkanes in triglycerides limits the amount of HVO that can be used as bioQAV. Worse still, vegetable oil yields are low for crops such as soybeans, typically less than 500 L / ha. Other crops, such as sugarcane, typically allow 65 to 95 tonnes / ha per year, producing up to 8550 L / ha of ethanol, with potential for further increases. That is, it can produce almost 20 times more ethanol than soybean oil from the same area, and this increases with the potential for cellulosic ethanol and energy sugarcane.

[0004] Ethanol from renewable sources is typically produced by fermenting sucrose using yeasts such as *Saccharomices cerevisiae*. Besides sucrose, other sugars, such as glucose derived from starch and xylose from hemicellulose, can also be fermented. Sucrose is obtained from sugarcane. Cellulose from bagasse can still be converted to glucose, and hemicellulose can still be converted to xylose and other sugars, which are also fermentable. Assuming the fermentation of a 6-carbon glucose molecule, 4 carbons will produce 2 ethanol molecules, and 2 carbons will produce 2 CO2 molecules. In this way, each ethanol molecule obtained also produces an unused CO2 molecule. After fermentation production using 7% to 10% ethanol in an aqueous medium, a large energy demand remains in the distillation step. The energy used for distillation is generated by burning most of the bagasse. Methods utilizing ethanol without the need for water separation would provide more raw materials for ethanol production. Furthermore, methods that can additionally utilize the large amounts of CO2 produced during fermentation have also attracted attention in this field.

[0005] Several pathways allow the conversion of ethanol into intermediate distillates, particularly QAV. These pathways typically involve the dehydration of ethanol to ethylene, followed by oligomerization of olefins.

[0006] Existing technology teaches that the first step in the conversion process is to dehydrate ethanol to ethylene according to the reaction: ethanol → ethylene + H2O.

[0007] Then ethylene oligomers can be made into components with molecular sizes compatible with diesel and QAV.

[0008] Recently, according to EAGAN, NM et al., “Chemistries and processes for the conversion of ethanol into middle-distillate fuels”, Nature Reviews Chemistry, Vol. 3, pp. 223-249, 2019, the Guerbet reaction of alcohol coupling was considered.

[0009] The Guerbert reaction originally involved the reaction: 2 ethanol → 1-butanol + H2O, and can occur continuously.

[0010] Patent US 4134926 teaches the dehydration reaction of ethanol in an acid catalyst (e.g., alumina, silica-alumina, activated clay, and zeolite) at at least 370°C in a fluidized bed to promote its regeneration. Lower temperatures favor the formation of diethyl ether rather than the dehydration reaction to ethylene.

[0011] Patent US 4847223 teaches the dehydration of liquid ethanol without water separation in a superacid catalyst composed of zeolite or silica-alumina and trifluoromethanesulfonic acid (CF3SO3H) at temperatures ranging from 170°C to 225°C. This document emphasizes the importance of processing diluted aqueous solutions of ethanol (those produced during sugar fermentation).

[0012] In the presence of olefins such as ethylene, oligomerization can be carried out to obtain olefins with higher molecular weights, as taught by reference US 8802905.

[0013] One type of ethylene oligomerization process with high conversion rates is carried out via transition metals (typically homogeneous), such as the Ziegler-Natta method taught in patent US 2943125. However, this oligomerization reaction is characterized by low selectivity, with the product distribution being of the Schulz-Flory type. The same distribution is achieved in supported catalysts (e.g., Ni) used for ethylene oligomerization. This necessitates more than one oligomerization step, such as the production of butene or higher olefins, followed by an acid-catalyzed oligomerization step, as taught in US 8957270 and US 9771533. Patent US 9840676 teaches the trimerization of ethylene to hexene, which further undergoes dimerization and trimerization, and is ultimately hydrogenated to yield C12 and C18 alkanes.

[0014] Selective one-step ethylene oligomerization via classical heterogeneous acid catalysis is difficult; preferred methods involve oligomerization to butene or higher olefins, including recycling of products below the distillate range, as taught in documents US7271304, US 9644159, and US 9663415. Even ethanol and / or ethylene can be converted to C3 to C6 olefins for further oligomerization.

[0015] Patent US 8378160 teaches how to obtain isobutanol through fermentation, dehydration to olefins, oligomerization in an acid catalyst, and subsequent hydrogenation. It also teaches the conversion of isobutene into aromatic compounds, and the alkylation of olefins with the resulting aromatic compounds.

[0016] Due to difficulties in obtaining ethanol, removing, converting, separating, purifying, and recycling olefins, methods for the direct conversion of ethanol to hydrocarbons in the distillate range are sought in the art. US 9475999 teaches such a method in which a first reaction is carried out in an ethanol zeolite acid catalyst to primarily yield olefins of 2 to 5 carbons, followed by a more stringent conversion to approximately 30% of the olefins, aromatics, alkanes, and cycloalkanes that have boiling points in the distillate range. Patent US4925996 also teaches a two-step conversion method. These methods are similar to those developed in the 1980s using zeolite catalysis, in which methanol obtained from syngas is converted to gasoline or diesel (Methanol to Diesel, MTD).

[0017] Because the initial oligomerization step may have low selectivity and problems such as catalyst deactivation, alternatives such as the production of longer-chain components from ethanol, such as the Guerbert reaction, have been explored.

[0018] The Guerbert reaction is a coupling reaction of alcohols. In the case of ethanol, it involves dehydrogenation to acetaldehyde, aldol condensation of acetaldehyde, and hydrogenation of the intermediate to butanol. This reaction can occur sequentially, producing C4-C6 alcohols, C6-C8 alcohols, or even C12-C16 alcohols, and can be combined with another acid oligomerization reaction following the dehydration of olefins of different chain sizes.

[0019] According to document US 9528058, the prior art teaches the use of up to 30% ethanol-derived Gelbert alcohol as a direct component of bioQAV, despite the disadvantages of using oxygenated compounds such as fuel stability and minimum calorific value.

[0020] Due to the difficulties involved in ethanol conversion, alternative types of fermentation are sought to obtain products with larger chain sizes and to facilitate oligomerization. One example is the production of isobutanol via fermentation, which is more readily converted into isobutene and oligomers, as taught in US 8975461.

[0021] As taught in US 8907150, some microorganisms produce acetone during fermentation, which is readily converted to mesitylene acid (1,3,5-trimethylbenzene) as a catalyst, along with other aromatic and phenolic alkyl compounds. In QAVs from Fischer-Tropsch, mesitylene can be used at up to 30% to improve some of its properties.

[0022] Acetylbutyl fermentation produces a mixture of butanol, acetone, and ethanol. US Patent 9790444 teaches the production of higher molecular weight branched alkanes via the condensation reaction of alcohols and aldols in the presence of a Guerbert-type catalyst, said catalyst having basic support such as hydrotalcite and hydrogenation / dehydrogenation capabilities (e.g., Pd and Cu). This document also teaches the coupling of acetone with one or more primary alcohols to produce higher molecular weight branched ketones. However, due to the inhibitory effect of water, this patent requires the water content in the reaction charge to be less than 5%.

[0023] Document US 10351487 teaches the direct processing of an aqueous ethanol solution into a functionalized light compound, primarily isobutylene, in a mixed oxide containing at least Zn and Zr. Isobutylene, ethylene, propylene, and acetone (excluding water) are formed as major products, but unfortunately, CO2 accounts for approximately 20% to 25% of the total carbon. In the same patent, they teach different catalyst formulations and conditions that can improve the acetone yield. Phenols with up to eight carbons are shown as byproducts of the synthesis of isobutylene and acetone.

[0024] The conversion of ethanol to acetone is known in the art, as taught by US 1663350. Ethanol and water are treated at a temperature of 250°C to 650°C with a metal oxide (preferably supported, most preferably alkaline earth metal oxide) from Groups 5 to 10 of the periodic table. An example is Fe₂O₃ supported on ZnO-CaO. The stoichiometry of the reaction is: 2ethanol + H₂O → CH₃COCH₃ + CO₂ + 4H₂. For every two ethanol molecules, one acetone molecule is formed, and one carbon atom is lost as CO₂.

[0025] To avoid obtaining intermediates such as acetone or olefins with a greater number of carbon atoms, and to avoid several conversion and processing steps, the art also teaches the direct fermentation of sucrose into products such as farnesene, and its hydrogenation to farnesane, as in US 7399323.

[0026] However, the ethanol pathway has a high sugar fermentation yield, even though for every 6 carbons in a unit of sugar (glucose), 2 carbons are lost as CO2.

[0027] In this sense, the direct conversion of sugars into hydrocarbons is of interest, as taught in US 20160326448. Another sugar conversion pathway involves hydrogenating sucrose or glucose into a polyol, reforming the aqueous phase of the polyol into an intermediate oxygen-containing compound (Pt / Pd in ​​zirconium oxide), and finally producing an alkyl-aromatic compound under acid catalysis with nickel supported on ZSM-5, the product being SAK (synthesized aromatic kerosene), which is used as a component of the QAV. However, for the sake of the aromatic compound's quality, the use of SAK in bioQAV is typically limited to 20% to 25%.

[0028] In addition to the direct use of sugar and other biomass components in the process of converting sugar into fuel, attention will also be paid to the use of CO2 products from fermentation itself and CO2 products potentially generated during bagasse combustion.

[0029] Another possible route is to produce methanol from gasified biomass and then use the MTD (Methanol to Diesel) process to convert that methanol into bioQAV, but this requires several processing, separation, and treatment steps. Furthermore, in the case of sugarcane, a large amount of bagasse is burned to provide energy for distilling diluted ethanol from fermentation, reducing its availability, and the remainder is burned to generate electricity.

[0030] Although bioQAV is used now and in the future, there is no clearly advantageous method for its production due to low agricultural productivity, multiple processing steps, low yield, and the unutilization of carbon available as CO2. Numerous inventions in the art demonstrate that no more advantageous method of obtaining it exists.

[0031] In their study, “Renewable bio-jet fuel production for aviation: A review,” Fuel, Vol. 254, pp. 115599, 2019, they provided an overview of the conversion technologies, economic assessments, environmental impacts, and current status of aviation biofuels. Furthermore, they taught methods for obtaining aviation biofuels, but did not specify the composition and concentration used in each step of each method.

[0032] Therefore, no prior art literature discloses a method for producing renewable aviation kerosene from ethanol, such as the method of this invention.

[0033] To address this problem, this invention was developed, which produces bioQAV by converting ethanol and, alternatively, methanol and / or CO2 or syngas into alkyl aromatic compounds via an alkaline catalytic pathway with hydrogenation / dehydrogenation. Summary of the Invention

[0034] The present invention relates to a method for producing renewable aviation kerosene (bioQAV), characterized in that ethanol, and optionally methanol and / or CO2 and / or syngas and mixtures thereof, are reacted in the presence of hydrogen in a catalyst (preferably heterogeneous) that combines basic and hydrogenation / dehydrogenation functions to produce alkyl aromatic compounds.

[0035] The catalyst and conditions of this invention allow for alcohol-linked Guerbert reactions, in which acetone is produced and coupled with other intermediates to alkyl-aromatic compounds within the QAV distillation range. The alkyl-aromatic compounds preferentially undergo hydrodeoxygenation to convert oxygen-containing compounds and the remaining olefinic unsaturated compounds, and optionally, the alkyl-aromatic compounds are hydrogenated to alkylcycloalkanes.

[0036] In a preferred embodiment of the invention, the hydrogen gas generated in the first step of the alcohol coupling reaction is used to hydrogenate at least a portion of the alkyl aromatic compound to alkylcycloalkanes.

[0037] In another embodiment of the invention, methanol or its precursor may also be combined with ethanol in the coupling reaction. Advantageously, CO2 produced during sugar fermentation into bioethanol may be used itself. Attached Figure Description

[0038] The invention will now be described in more detail with reference to the accompanying drawings, which represent an example of implementation of the invention in an illustrative and non-limiting manner. In the drawings, the following are present:

[0039] - Figure 1This invention illustrates a method for producing ethanol from the fermentation of sugarcane (Saccharum Officinarum). The diagram shows the fermentation steps of sucrose (Ferm.), conversion of sugarcane bagasse (Conv.Bag.) to syngas and / or methanol (MeOH), a coupling step (Gelbert), followed by separation (Sep.), where the organic liquid effluent, along with the generated H2, enters a hydrodeoxygenation reactor (HDO), and finally hydrogenates to alkylcycloalkanes (ALK-NAFT) in a final hydrogenation reactor (HYD). Detailed Implementation

[0040] According to the present invention and in a particular embodiment of the present invention Figure 1 The method for producing renewable aviation kerosene (bioQAV) from ethanol derived from sugar fermentation, as shown, is characterized by the ethanol coupling reaction being catalyzed by a combination of hydrogenation / dehydrogenation and basic functions (as catalysts for the Guerbert reaction). In addition to the Guerbert alcohol coupling reaction, the catalyst of the present invention also promotes cyclization into aromatic compounds. Without limiting the invention to understanding the reaction mechanism, it is considered that the synthesis of acetone or intermediates and their condensation, as well as reactions between alcohols via aldol condensation, occur parallel to the Guerbert reaction.

[0041] The Guerbert reaction involves the reaction of primary alcohols and / or secondary alcohols (or mixtures of alcohols) in the following steps:

[0042] - The dehydrogenation reaction of alcohols (primary alcohols) to aldehydes: 2 ethanol molecules dehydrogenate to acetaldehyde (producing 2 H2); other primary and secondary alcohols also dehydrogenate (methanol dehydrogenates to formaldehyde, butanol dehydrogenates to butyraldehyde);

[0043] - Aldol condensation: Aldol condensation between two molecules (aldehyde or ketone) containing a carbonyl group, followed by the elimination of water; producing an intermediate enone (αβ-unsaturated acetone) (the intermediate molecule coupled with two ethanol molecules can be decarboxylated to produce acetone instead of eliminating water);

[0044] - Hydrogenation reaction: The ketone is hydrogenated with H2 generated from the original hydroxyl group of the alcohol to produce butanol;

[0045] - Synthesis of acetone or intermediates: This occurs prior to decarboxylation of the intermediate from the Guerbert reaction, resulting in:

[0046] 2CH3CH2OH+H2O→CH3COCH3+CO2+4H2

[0047] The acetone synthesis reaction depends on water as a reagent, which originates from the Guerbert condensation reaction and is produced through the formation of ethers (e.g., diethyl ether) or the dehydration and dehydrogenation reactions of cyclic compounds. In addition to the water produced in the reaction, more water can be provided to the feedstock. More preferably, it comes from an ethanol solution from fermentation.

[0048] In the described reaction steps, in addition to ethanol, corresponding intermediates aldehydes and ketones, or even acetone, and other alcohols such as formaldehyde derived from methanol are used. Furthermore, methanol precursors can be used to form methanol in situ, or mixtures of methanol and precursors.

[0049] Acetone is highly reactive and, under basic catalysis, reacts to yield mesitylene oxide, mesitylene, and isophorone, which then react with phenols and aromatic compounds.

[0050] The catalyst and conditions of this invention allow two pathways to occur simultaneously, with aldehydes from both ethanol and its derivatives, and acetone and its derivatives, reacting with each other to undergo aldol condensation. Furthermore, the catalyst can facilitate the coupling reaction of intermediate phenolic compounds with alcohols (including methanol).

[0051] In addition, the catalyst of the present invention catalyzes the CO2 hydrogenation reaction and the water-gas shift reaction and their reverse reaction during the reaction, causing the CO2 formed in the reaction or fed to the reactor to be converted into methanol and formaldehyde, and continue the aldol condensation reaction.

[0052] In a preferred embodiment of the invention, CO2 generated during fermentation for ethanol production is fed into a coupling reactor.

[0053] In another preferred embodiment of the invention, sugarcane bagasse or biomass is sent to gasification to produce methanol, or directly sent to an ethanol coupling reaction.

[0054] Although the present invention uses ethanol from renewable energy sources, and preferably methanol from renewable sources, in order to obtain renewable aviation kerosene, ethanol and methanol (or methanol precursors, such as CO2) from other non-renewable sources may be used in whole or in part, and the renewable content of the so-called renewable aviation kerosene is proportional to the renewable content of the reagent.

[0055] When using methanol, a two-step coupling reaction is preferred to avoid the formation of undesirable C3 oxygen-containing compounds, although this reaction is more time-consuming. Therefore, methanol and formaldehyde react more rapidly with higher molecular weight alcohols and phenols, increasing the product content across the middle distillate range.

[0056] Other parallel reactions are known, but occur at a lower degree, producing dienes and alkenes. These light compounds can be recycled to the reaction or used for the alkylation of aromatic compounds.

[0057] The mixture of alkyl aromatic compounds and oxygen-containing products from the condensation reaction can be hydrodeoxygenated, particularly hydrodeoxygenation (HDO), in a second-step oxygen removal reaction. Preferably, the products of the ethanol coupling reaction pass through HDO, which both provides stability for the stream to be used as a bioQAV and promotes the hydrogenation of the alkyl aromatic compounds to alkylcycloalkanes in the final hydrogenation step.

[0058] Furthermore, it was found that a large amount of hydrogen is generated in coupling reactions (including dehydrogenation reactions in the formation of aromatic compounds), and the generated H2 can facilitate the conversion of CO2 and CO as well as subsequent hydrodeoxygenation and hydrogenation reactions, thereby reducing the demand for external H2.

[0059] Alternatively, the intermediate oxygen compound can be sent back to the first step of the ethanol coupling reaction.

[0060] Oxygen removal can occur through at least two mechanisms. In addition to direct HDO, it can also be catalyzed by a combination of hydrogenation and acidic functions, in which the carbonyl group of an aldehyde is hydrogenated to an alcohol, the alcohol is dehydrated to an alkene, and the resulting alkene is hydrogenated to an isoalkanes or not hydrogenated to an isoalkanes, depending on the catalyst and the conditions of the hydrodeoxygenation reaction.

[0061] In addition to the aforementioned dehydration and hydrogenation mechanisms, direct HDO from alcohols and carbonyl groups can also occur.

[0062] The alcohol coupling step and the alkyl aromatic compound product of HDO can be further hydrogenated completely or partially to alkylcycloalkanes. This reaction favors increased density, utilizes the H2 produced in the reaction itself, and ultimately enables greater utilization for bioQAV, which, as specified in the specification, has the maximum capacity for aromatic compounds.

[0063] The HDO and hydrogenation reaction steps of aromatic compounds can also occur in the same reactor or with the same catalyst.

[0064] Typically, the HDO step is separated from the hydrogenation step of aromatic compounds because some typical HDO catalysts (e.g., Mo or W sulfides, promoted by Co and Ni or not) are almost inactive for the hydrogenation of aromatic compounds.

[0065] The coupling of the alcohol in the first reaction step and the subsequent HDO step can both occur in the same reactor or in different reactors. Preferably, they occur in different reactors, wherein unreacted oxygen-containing compounds from the aldehyde coupling reaction step are recovered and recycled back to the coupling reactor.

[0066] In the ethanol coupling reaction step, MeOH can be used as a packing material, or MeOH can be generated in situ from CO and hydrogen, CO2 and hydrogen, or mixtures thereof. In fact, CO2 is generated by the parallel reaction / intermediate acetone synthesis reaction itself. A mixture of CO, CO2, and H2 gases can still be combined with MeOH in the reactor feed. Formaldehyde can also be fed to the reactor in addition to methanol, as it is a reaction intermediate produced by the methanol dehydrogenation reaction. However, it is preferred to use MeOH and / or a combination with syngas, because formaldehyde can polymerize, hindering access to the catalyst site. Under the conditions of this invention, chemical equilibrium calculations show that the amount of formaldehyde formed is small, and the absence of formaldehyde in product analysis indicates that the reaction is rapid.

[0067] The hydrogenolysis of methanol to CO and H2 is endothermic, while the synthesis of MeOH from CO and H2 is exothermic. To reduce the heat supply requirements in the reaction conditions, the combination of methanol and synthesis gas (CO and H2) in the feed can be advantageous, making the temperature distribution in the reactor close to isothermal, which is conducive to coupling reactions.

[0068] Therefore, the coupling reaction of ethanol can be driven by CO and H2, or a mixture of CO2 and H2, or a mixture thereof, or supplied by MeOH or a gaseous mixture. When the feed contains CO (syngas), the presence of H2 affects the methanol synthesis reaction. If CO2 is used as the reagent, the hydrogenation reaction requires a higher level of H2. Two H2 molecules are needed for the hydrogenation of CO to methanol, and three H2 molecules are needed for the hydrogenation of CO2 to methanol. Coupling reactions with compounds containing one carbon atom (MeOH or H2 with CO or CO2 or even a mixture of formaldehyde) occur only under sufficient conditions to form methanol and subsequently formaldehyde.

[0069] MeOH synthesis can be carried out in separate reactors before being mixed with ethanol, or it can be formed in situ in parallel with a coupling reaction.

[0070] The catalyst used in the coupling reaction step has basic and hydrogenation / dehydrogenation functions. Typical temperatures are above 150°C, preferably above 250°C, and more preferably above 350°C. While temperatures up to 550°C can be used, temperatures above 450°C are unnecessary and lead to increased formation of secondary reactions.

[0071] Higher pressures are thermodynamically favorable for alcohol coupling reactions. Typical pressures are at least 1 bar, usually greater than 5 bar, preferably greater than 10 bar, more preferably greater than 20 bar and less than 60 bar, and even more preferably less than 100 bar. Although pressures up to 200 bar can be used, pressures greater than 60 bar result in a smaller gain and are not preferred conditions. Conditions of 20 to 40 bar are preferred and sufficient for the reaction. Higher pressures may be required when a larger amount of CO2 is fed into the reaction, but are limited to the values ​​described above.

[0072] Since H2 is produced in the reaction, it is of interest to have sufficiently high pressures to use the same gas (after separating CO2 and CO) for the HDO step. Preferably, a portion of the gaseous effluent from the coupling reaction is returned to the coupling reaction itself for use in the synthesis of formaldehyde and its coupling reaction.

[0073] Temperature and pressure are related because higher pressures are unfavorable for dehydrogenation reactions, and higher temperatures are required to maintain the same level of dehydrogenation reaction. However, very low pressures necessitate increased reaction times. The conditions of this invention are ideal for alcohol coupling reactions and the synthesis of alkyl aromatic compounds.

[0074] In this invention, various contact forms between the catalyst and reactants are possible. Batch mixing reactors, continuous mixing reactors (CSTRs), batch or continuous reactors with homogeneous catalysts, reactors with heterogeneous catalysts, fluidized beds, or conveying types (risers) can be used; preferably, continuous reactors with fixed-bed heterogeneous catalysts are used. The use of heterogeneous catalysts facilitates the separation between the products and the catalyst. Since the ratio between the basic function and the hydrogenation function results in minimal catalyst deactivation, the preferred contact form between the reactants and the catalyst is to carry out the reaction continuously with a fixed-bed catalyst and plug flow. Other continuous reactor configurations are possible, such as sludge beds and fluidized beds, but they offer no advantage over the preferred method of continuous reaction with a fixed bed. Furthermore, homogeneous catalysts (basic catalysts) and heterogeneous catalysts (hydrogenation / dehydrogenation catalysts) can be combined.

[0075] For continuous reactions in a fixed bed, the batch volume processed per unit time per unit reactor volume (LHSV) is typically 0.1 hours. -1 Up to 10 hours -1 Preferably, the LHSV (load volume per reactor volume per hour) is 0.2 hours. -1 Up to 5 hours -1 More preferably 0.5 hours -1 Up to 2 hours -1 .

[0076] The addition of water promotes acetone synthesis, accelerates coupling reactions, and inhibits undesirable etherification reactions.

[0077] Alternatively, an ethanol-water solution from the fermentation itself can be used, preferably provided by pre-evaporating the mixture for purification. The use of an ethanol-water solution avoids the high energy requirements of distillation for recovering ethanol from fermentation. When an organic and aqueous phase are formed, the water in the feed, along with the water from the alcohol coupling reaction and HDO, is easily separated from the coupling products or HDO due to polarity differences.

[0078] Hydrogen is not essential for this reaction, as it is produced and consumed in the coupling reaction itself and in the synthesis of acetone. However, the presence of hydrogen is desirable for increasing the activity time and can facilitate the easier hydrogenation and deoxygenation of alcohols compared to aldehydes or ketones.

[0079] It should be understood that the working mechanism of hydrogen is that the presence of hydrogen keeps the catalyst partially reduced, or to the desired degree of reduction for metal hydrogenation / dehydrogenation functions, which is conducive to the evaporation and hydrogenation of reaction intermediates such as ketenes, which may lead to the formation of coke on the catalyst.

[0080] When a mixture of CO and / or CO2 is used in the Goerbert reactor, the H2 required for the synthesis of MeOH is not included in the calculation. When H2 is used additionally, the typical H2 ratio is 0 NL H2 / L ethanol to 500 NL H2 / L ethanol, preferably 0 NL H2 / L ethanol to 100 NL H2 / L ethanol, more preferably 20 NL H2 / L ethanol to 50 NL H2 / L ethanol, where NL refers to standard liters, i.e., the number of liters of gas under standard temperature and pressure conditions. Preferably, H2 is not essential but can be used to heat the reactor bed and for catalyst activation or regeneration.

[0081] The Guerbert reaction produces H₂O as a byproduct, which can react with methanol and CO in the water-gas shift reaction to produce more H₂. Metals with hydrogenation / dehydrogenation capabilities are known to catalyze these reactions. As known to the present art, MeOH can undergo several reactions, the main ones being the conversion of MeOH to DME and formaldehyde, which can further react to give methyl formate, decomposing into CO₂ and methane or CO and H₂.

[0082] Copper is known to be a catalyst for the hydrogenation reaction of CO and CO2 to methanol, the key question being whether ZnO can promote the reaction. Other active metals used in the reaction include Fe, Ni, Pd, Pt, Rh, and Ru.

[0083] When a portion of ethanol and methanol is converted into syngas (CO and H2) and CO2 during the reaction under the conditions of the present invention, a recirculating gas compressor is preferably used to return the gas phase feed to the reactor. A portion of the gas can be purged and fed with H2 to maintain the H2:CO ratio at 2:1 mol / mol. More preferably, a recirculating compressor is provided for recompressing the product gas and returning it to the reaction.

[0084] The methods of gas recompression, inertization, and separation of other byproducts such as methane are known to those skilled in the art and do not constitute an inventive fact.

[0085] Known homogeneous alcohol coupling catalysts include salts, hydroxides, and alkoxides, which may or may not be associated with hydrogenation / dehydrogenation catalysis, and can be homogeneous or heterogeneous. Preferably, a heterogeneous catalyst is used; more preferably, a metal with hydrogenation / dehydrogenation function supported on a basic support or a support containing a basic component is used.

[0086] As a basic carrier or component, oxides, hydroxides, phosphates, carbonates, and carbides of Group IA and Group IIA elements, alkali metals, and / or alkaline earth metals such as K, Na, Ca, Cs, Sr, Ba, and Rb can be used. Only one basic component or a mixture of components, such as mixed oxides, can be used.

[0087] Alternatively, a support such as alumina, silica, or zeolite can be used, which is doped with alkaline components such as K, Ca, or Mg (usually as oxides (K2O, CaO)).

[0088] The support itself can be basic, such as alkaline earth metal oxides (e.g., MgO, CaO, SrO, BaO) and rare earth oxides (e.g., CeO, La2O3, Sm2O3). Besides Al2O3, other oxides provided by the present invention as supports include ZrO2, Y2O3, ZnO, TiO2, MoO3, and ThO2. They can also be binary oxides, such as ZnO-Al2O3 and MgO-TiO2. Generally, the alkali metal ions supported on alumina, silica, and the aforementioned oxides are primarily alkaline earth metal oxides. Ions are mainly used as oxides, but can also be non-oxides, such as KF and KCl supported on alumina, as well as lanthanide imides and nitrides.

[0089] Alkaline zeolites can also be used as the alkaline component in this invention. They can be ion-exchanged to contain alkaline ions such as Na-X, Cs-X, or to contain added bases such as Cs₂O / Cs-X. Zeolite exchange can contain alkaline metals, transition metals already mentioned, rare earth elements, and high-valence oxides.

[0090] Alkaline clays—mineral clays such as limestone, dolomite, magnesite, olivine, sepiolite, peridot, and hydrotalcite are also known.

[0091] Hydrotalcite is a layered double hydroxide in which divalent cations (e.g., Mg, Mn, Fe, Co, Ni, Cu, Zn, Ga) are bonded to trivalent metals (Al, Cr, Mn, Fe, Co, Ni, La), along with compensating anions between the layers. Hydrotalcite can also be doped with other metals. Hydrotalcite can be calcined or uncooked, and depending on the conditions, it produces mixed oxides and spinels.

[0092] Hydroxyapatite is also known in the art as an alkaline catalyst.

[0093] Perovskite, β-alumina, hydroxides, and metal carbonates can also be used. Other supports include nitrides, nitrates, metals, or supported sulfides, sulfates, carbides, phosphates, and fluorides; activated carbon and impregnated carbon; anion exchange resins; organic bases supported on microporous or mesoporous metal oxides; and typically solid or supported alkali metals, alkaline earth metals, or basic organometallic compounds. However, this invention is not limited to the properties of the components that impart basic functionality to the coupling catalyst used; different basic compounds can achieve the same basic function in the reaction.

[0094] The most widely used carrier in industry is alumina, primarily γ-alumina. γ-alumina has an undesirable inherent acidity but possesses good surface area and pore distribution, and can be doped with alkali metals and / or alkaline earth metals, such as K, Na, Ca, Cs, or Rb.

[0095] The hydrogenation / dehydrogenation function in the coupling catalyst can be a single or combined transition metal, specifically from Group VB, Group VIB, Group VIIIB, and Group IB, such as V, Cr, Mo, W, Fe, Ru, Rh, Re, Co, Ni, Cu, Ag, Sn, Pb, Zn, Mn, Pt, and Pd. Preferably, the metal is Cu and / or Ni. The metal may be promoted by other metals (e.g., Zn) or may not be promoted by other metals (e.g., Zn). The metal may exist as an oxide, hydroxide, salt, or reduction. The metal may also exist as a homogeneous catalytic system, which may be supported or unsupported.

[0096] Mixtures of different catalysts, i.e., basic solids and hydrogenation catalysts, can also be used, but preferably, the basic function and hydrogenation function are combined in the same catalyst. Furthermore, the basic function can exist as a homogeneous or heterogeneous catalyst, and similarly, the hydrogenation / dehydrogenation function can exist in a homogeneous or heterogeneous form; it is possible to have a homogeneous basic phase with a supported hydrogenation catalyst, or a heterogeneous basic phase and a homogeneous hydrogenation function. However, the preferred catalyst combines both functions in the same heterogeneous catalyst.

[0097] In a particular embodiment of the invention, the catalyst is Cu deposited on potassium-doped γ-alumina. The prepared catalyst containing the copper substance Cu(I) exhibits higher coupling reaction activity than fully reduced copper. Cu(I) can be prepared using a precursor such as CuCl2, which is reduced to CuCl upon reaction with KOH on the catalyst surface. A preferred method for preparing this catalyst is to deposit CuCl2 on alumina, calcine it, then deposit KOH, followed by a final calcination.

[0098] Another promoter for Cu(I) and Cu(II) is ZnO present on a support. Additionally, ZnO can be combined with K or other basic components. One known support is a mixture of ZnO and Al₂O₃. The use of Cu catalysts in a mixture of ZnO and Al₂O₃ is industrially known, particularly for the hydrogenation of CO (and CO₂) to methanol.

[0099] The Cu content in the catalyst can be at least 1% by weight, preferably greater than 2% by weight and less than 10% by weight, and preferably in the range of 5% by weight. The KOH content in the alumina is at least 5% by weight and less than 30% by weight, preferably greater than 10% by weight and preferably equal to 20% by weight. Amounts greater than 30% by weight lead to pore blockage and a significant reduction in catalyst surface area.

[0100] In addition to Cu, other metals can be used with Cu as promoters for dehydrogenation reactions and methanol activation reactions, such as, but not limited to, Pd, Pt, and Fe.

[0101] Unreacted alcohols and aldehydes can be separated from the products of the ethanol reaction and fed back to the coupling reaction, as well as diethyl ether. The entire effluent can still be partially hydrogenated and deoxidized before separation.

[0102] In addition to alkyl aromatic compounds and other major phenolic compounds, other byproducts may be formed during the reaction, such as diethyl ether (DEE), dimethyl ether (DME), ethoxyethane, esters and other oxygen-containing compounds.

[0103] Some of these byproducts can be reused through hydrolysis. Hydrolysis can be readily carried out by reacting ethers with water on an acid catalyst, such as an acidic ion exchange resin or an acid catalyst known to the present technology. For hydrolysis, water needs to be supplied to the hydrolysis reactor at least in stoichiometric ratios.

[0104] Alternatively, the ether or a mixture of the remaining ether and alcohol can be directly recycled to the main reactor for hydrolysis. In this particular case, it is of interest to feed H2O into the reaction charge. More preferably, water can also be fed into the reactor coupling charge to avoid etherification and dehydration reactions.

[0105] Depending on the amount of water present in the product, the effluent from the coupling step is separated into two phases. In the presence of methanol in the product, some methanol is retained in the aqueous phase, facilitating its separation and reuse in the coupling reaction. Alternatively, a liquid-liquid extraction scheme can be used, preferably with water flowing countercurrently relative to the organic phase, to separate methanol and unconverted ethanol. Preferably, ethanol and methanol are separated for reuse in the coupling reaction.

[0106] Separation methods such as distillation are known at the existing level of technology and do not constitute novelty of the invention.

[0107] Following the alcohol coupling reaction, unreacted aldehydes and ketones are preferentially returned to the reaction. Furthermore, alkenes and light dienes present in the product can be reacted with benzene, toluene, and styrene to produce higher molecular weight compounds in the C8+ range.

[0108] Following the coupling step, there is an HDO and / or hydrogenation reaction step. Without methanol removal after coupling, it can be converted to dimethyl ether in HDO (via acid function in the catalyst) or to methane upon hydrogenation; both reactions also produce water. The same may happen with unreacted ethanol, which is converted to ethane in HDO, leading to unnecessary H2 consumption. Similarly, the gaseous effluents CO and CO2 from the first reaction can also be converted to methane in the HDO step, which is undesirable because it consumes H2 and does not allow for the reuse of carbon in the coupling.

[0109] Preferably, CO and CO2 have been removed from the H2 to be fed to the HDO and hydrogenation reaction steps. The means for removing CO2 and CO are known in the prior art.

[0110] Therefore, preferably, the gas containing H2, CO, and CO2 effluent from the coupling reaction is returned to the coupling reaction, and the H2 is completely or partially removed to maintain the desired molar relationship between MeOH and the MeOH precursor. Additionally, it may be necessary to purge a portion of the gas to avoid the accumulation of inert components (light hydrocarbons, primarily methane) formed during the reaction. The methane and light components formed during the reaction can be fed to the syngas / MeOH production unit.

[0111] Therefore, although two different catalyst beds can be used in the same reactor, one for coupling and the other for HDO, it is preferable to separate the light components and product gases from the coupling step before the HDO step to prevent H2 from being consumed due to the reaction with CO2.

[0112] Typically, under the reaction conditions of the present invention, the conversion rate of ethanol is greater than 75%, more usually greater than 95%, and the remaining ethanol can be separated by means known to the prior art, such as distillation, and returned to the coupling reactor.

[0113] For the subsequent hydrodeoxygenation (HDO) reaction, several heterogeneous catalysts are known and widely used in current technologies.

[0114] Commercially available catalysts are typically used as hydrogenation catalysts: supported on solids such as alumina, silica, silica-alumina, zeolite, hydrotalcite, mixed oxides, spinel, MgO, TiO2, ZnO, CeO2, phosphates, sulfonic acid resins, ZrO2, sulfated Zr, carbon, activated carbon, etc., promoted by Ni or Co, or Mo or W sulfides.

[0115] Ni-promoted Mo sulfides supported on γ-alumina hydrotreating (HDT) catalysts are more common. Typical contents supported on Al₂O₃ are 10% to 20% by weight, typically 15% by weight of Mo, plus 5% Ni (e.g., MoO₃ and NiO). Optionally, W sulfides or mixtures thereof with Mo can be used, and alternatively, Co can be used instead of Ni or as a promoter in addition to Ni. These catalysts are widely commercially available and used in HDT of petroleum fractions. Sulfidation is required before using the catalyst, or a pre-sulfided catalyst (also commercially available) is required. When using sulfide catalysts, continuous or intermittent doping with sulfur compounds may be necessary to maintain the sulfide catalyst.

[0116] Besides sulfide catalysts, fully or partially reduced metals such as Pt, Pd, Ru, Ni, Cu, Mo, W, Co, Ir, Rh, Au, Ce, Fe, Mn, Ga, Pb, and Bi can also be used. These metals are typically supported on the same supports as described above. Other catalysts besides reducing metals include oxides, phosphates, carbides, and nitrides, such as MoO3, NiP, MoC2, and CoN. x It is known.

[0117] Specifically, MoO3 with vacancies due to the presence of H2 has the ability to remove carbonyl oxygen and alcohols, thereby producing α-olefins. Besides MoO3, Mo carbides and nitrides can also induce direct HDO of alcohols and carbonyl groups. The working mechanism of the catalyst is through oxygen vacancies generated by H2, activated by the Mars-Van Krevelen reverse CO bond. The same mechanism occurs in the cases of RuO2, IrO2, PdO, and Rh2O3, in addition to MoO3. Other catalysts with lower activity, besides CuO, Ag2O, and Au2O3, include SnO2, ZnO, VO2, TiO2, and CeO2.

[0118] Some carriers are oxyphilic, having an affinity for oxygen, which can favor HDO, such as carbon, alumina, TiO2, and ZrO2. Acidity is also required for the activation of oxygen-containing compounds (including alcohol dehydration reactions).

[0119] It is also known that acidity affects alcohol dehydration reactions, which can facilitate greater hydrogenation of HDO via dehydration mechanisms, as is the case with alumina-supported catalysts. Furthermore, the acidity of some supports can promote the dispersion of the metal functions of HDO.

[0120] However, the direct mechanism of the hydrodeoxygenation reaction is preferred.

[0121] Typical pressure conditions ranging from 5 bar to 100 bar, preferably 10 bar to 50 bar, and more preferably 20 bar to 40 bar, are sufficient to convert the remaining oxygen-containing compounds (alcohols, phenols, aldehydes, esters) into hydrocarbons without requiring higher pressures. Typical temperatures are in the range of 200°C to 400°C, preferably 200°C to 350°C, and more preferably 250°C to 325°C. Lower temperatures reduce the hydrodeoxygenation reaction, while higher temperatures may lead to deactivation.

[0122] Finally, after the HDO reaction, hydrogenation reactions of alkyl aromatic compounds to alkyl cycloalkanes can be carried out.

[0123] Typical catalysts for the hydrogenation of aromatic compounds can be Ni or noble metals such as Pt, Pd, Ru, Rh, and Re. Supports include alumina, silica-alumina, zeolite, activated carbon, Ti, basic oxides, and clay.

[0124] Typical pressure conditions in the range of 5 to 100 bar, preferably 10 to 50 bar, and more preferably 20 to 40 bar, are sufficient to convert the remaining oxygen-containing compounds (alcohols, phenols, aldehydes, esters) into hydrocarbons without requiring higher pressures. Typical temperatures are in the range of 150°C to 300°C, preferably 150°C to 250°C, and more preferably 200°C to 250°C. Lower temperatures reduce the hydrogenation reaction, while higher temperatures may lead to hydrogenolysis.

[0125] Since the hydrogenation reaction is exothermic, in addition to using liquid or gas quenching at different points in the reactor, it may also be necessary to recycle the alkyl cycloalkanes in the reaction charge.

[0126] Furthermore, the HDO and hydrogenation reaction steps of aromatic compounds can be combined in the same reactor. The reactor can have a catalyst in a separate bed, with the HDO catalyst being the preferred part that first contacts the feed. Alternatively, the HDO and hydrogenation reactions can be mixed.

[0127] Another specific arrangement of the invention is to carry out the HDO and hydrogenation reactions of aromatic compounds in the same catalyst. Therefore, sites with hydrodeoxygenation and / or acid functions can be combined with hydrogenation functions. In a preferred configuration of the invention, the support can have an acid dehydration reaction function plus a metal with a hydrogenation function. Any of the above-mentioned sites and components can be used for combined deoxygenation and hydrogenation reactions, as is known to those skilled in the art. Several options are feasible, and possible catalyst variations for the HDO and hydrogenation steps, or combinations thereof, are provided to process the coupling reaction effluent. The final product is obtained as a mixture of alkyl aromatic compounds and alkyl cycloalkanes, or solely as alkyl cycloalkanes.

[0128] The methods for obtaining reagents, the methods for separating products, the methods for carrying out reactions in reactors, the means for recycling products, and the means for heat exchange are known in the prior art, and the present invention will not be altered by using any other means known in the prior art not listed in this invention.

[0129] However, it is also clear that the properties of coupling catalysts exhibiting basic sites and hydrogenation / dehydrogenation sites are not a limitation of the present invention. Several heterogeneous or homogeneous catalysts or combinations thereof can catalyze the ethanol coupling reaction of the present invention, optionally in the case of CO2 and methanol, to produce an alkyl aromatic compound component and optionally an alkyl cycloalkane component after the hydrogenation reaction.

[0130] Example:

[0131] In the following embodiments, the embodiments are presented to illustrate certain implementations of the invention and should not be construed as limiting the invention.

[0132] Example 1: Testing of catalysts from existing technology

[0133] After activation at 400°C in an H2 atmosphere for 4 hours, the catalyst was tested in a laboratory-scale continuous reactor (10 mL catalyst bed) at 350°C. The feed was ethanol, the pressure was 30 bar, and the LHSV was 1 hour. -1 The H2 / feed ratio is 6 mol H2 / mol ethanol.

[0134] A commercial catalyst consisting of CoO (5 wt%) + MoO3 (15 wt%) in hydrotalcite (30 wt% MgO) showed reactivity for the etherification of ethanol to dimethyl ether and the hydrogenation of ethylene products from dehydration reactions. A Ni catalyst (20 wt%) in MgO showed preferred ability for the hydrogenolysis of ethanol to produce methane.

[0135] Example 2: Copper catalyst in an alkaline support

[0136] Impregnate 1 / 16 of 100 g of extruded alumina with a CuCl2·2H2O solution in ethanol, corresponding to the pore volume of the alumina, to obtain 5 g of Cu. The Cu-containing alumina is then dried for 24 hours and calcined at 420 °C for 4 hours to obtain the intermediate Cu / Al.

[0137] Several catalysts were obtained by adding an alkaline solution to the intermediate. Sodium hydroxide, magnesium hydroxide, calcium hydroxide, and potassium hydroxide were added in ratios of 5 g, 10 g, 20 g, and 30 g of metal per g of alumina, respectively, and the catalysts were then calcined at 420 °C for 4 hours.

[0138] Potassium-containing catalysts, specifically those containing 20 g K / 100 g raw Al₂O₃, exhibited high conversion and selectivity for the Guerbert reaction. Contents greater than 20 g K / 100 g Al₂O₃ decreased the mechanical strength of the catalyst. A 5% Cu content proved sufficient for the dehydrogenation reaction step.

[0139] Using another copper salt (nitrate, Cu(NO3)2) instead of CuCl2 resulted in significantly lower catalyst activity. Without limiting the invention to the working assumptions of the reaction, Cu(I) is considered to be more reactive in dehydrogenation than Cu(O) obtained primarily from nitrates.

[0140] Example 3: Experiment on ethanol coupling reaction in a pilot reactor

[0141] An alumina-supported catalyst was used, wherein 5 g of Cu (from CuCl2) and 20 g of K (from KOH) were added to 100 g of base, as described in Example 2.

[0142] In a downflow pilot reactor, 100 mL of the catalyst from Example 3 was added.

[0143] The catalyst was activated at 400°C and 30 bar H2 pressure for 4 hours.

[0144] The feed has different ethanol contents, ranging from 10% ethanol solution in water to 100% ethanol. The temperature testing range is 360°C to 460°C, the pressure is 30 bar, the H2 / feed ratio is 60 NL / L to 420 NL / L, and the LHSV is 0.5 hours. -1 Up to 6 hours -1 .

[0145] Temperatures of 360°C proved insufficient, resulting in low ethanol conversion, while temperatures of 460°C were too high, increasing the formation of diethyl ether.

[0146] Adding water to the reaction mixture has proven advantageous, resulting in high ethanol conversion and very little diethyl ether (DEE) formation. In the absence of water, it is possible to suppress DEE formation only at lower temperatures and higher LHSVs; however, under these conditions, ethanol conversion is lower.

[0147] Table 1: Results of the coupling experiment

[0148]

[0149] Table 2 presents the chromatographic results for experiments 8, 9, 22, and 23 under the conditions described in Table 1. It was observed that the addition of water in experiments 8 to 9 reduced DEE formation and increased the content of all products. Further increases in water content (experiments 9 to 22), processing feeds with only 10% ethanol resulted in lower light component content; although benzene content increased, it also reduced C7 and C8 and increased C9 to C17. The additional H2 in experiment 23 reduced the total light component and increased the content of intermediates C7 to C9, maintained high yields of C10 to C15, and reduced C17+.

[0150] Typically, the content of C8 to C17 compounds (including aromatic compounds) in the product increases from 47% to 76.25% with the addition of water.

[0151] Analysis of the light fraction still revealed a large amount of olefins and dienes, which can be alkylated by acid-catalyzed reaction with light aromatic compounds (benzene and toluene), thereby increasing the yield of C8 to C17 fractions.

[0152] Example 4: Experiment of ethanol coupling reaction with methanol in a pilot reactor

[0153] To evaluate the presence of methanol in the coupling reaction, loading tests were conducted with ethanol and methanol, as well as with ethanol and methanol plus water.

[0154] Table 3 presents the results of experiments 8, 9, 22 (without methanol) and experiments 25 and 27 (with methanol in the feed).

[0155] The results showed that, compared with the product without methanol in the feed, methanol mainly reacted with ethanol in the presence of methanol in the feed to form a large number of C3 compounds (alcohols and aldehydes), which reduced the production of C8+ aromatic compounds.

[0156] The results also showed that the presence of water was preferred even when the feed contained ethanol and methanol.

[0157] Table 2: Results of Experiments 8, 9, 22 and 23

[0158] test 8 9 22 23 %EtOH 100 50 10 10 <![CDATA[LHSV, hour -1 > 0，5 0，5 0，5 0，5 T，℃ 430 430 430 430 <![CDATA[H2 / Charge, NL / L]]> 60 60 60 420 Product % EtOH 0,80 0，63 0，02 0，07 %DEE 22，20 2，17 0，53 0，38 Light components 15，10 21，32 6，18 7，09 benzene 4，30 5，78 7，88 5，18 C7 7，78 9，86 4，92 6，46 Toluene 2，87 2，25 5，91 6，28 C8 5,16 7,62 4，24 6，19 |Ethylbenzene 2，93 2，91 4，26 5，31 xylene 3,49 2,25 4，55 2,65 styrene 0,41 0,87 0，53 0，45 C9 7,76 10,07 11，84 13，76 C10 9，33 10,58 12,67 12,13 C11 4,81 6,63 6,84 7,08 C12 3，76 4,66 6,40 6,10 C13 3,44 3,96 5，49 5，08 C14 2,66 3，26 6,29 5,34 C15 1，03 1,24 2，62 2,23 C16 1,52 2,26 4,80 3,77 C17+ 0，69 1,59 573 4,39 The sum of C8 to C17+ 46，98 57,91 76,25 74,48

[0159] Example 5: Experiment of methanol coupling reaction in the final step in a pilot reactor

[0160] Since many C3 compounds are formed in the coupling reaction when methanol and ethanol are directly mixed, the possibility of using methanol after the first ethanol conversion step is being evaluated.

[0161] The test product mixture was used prior to ethanol coupling. The resulting product mixture is shown in column 1 of Table 4.

[0162] Add the same volume of methanol to mixture 1 to produce a charge mixture 1 + MeOH.

[0163] Under the same conditions of T, LHSV, and H2 / charge ratio in Experiment 25, the product exhibited a lower C3 compound content due to the reaction with the remaining EtOH from charge mixture 1, wherein a significant amount of methanol was converted into the heavier product. Compared to previous examples, the addition of methanol after the first coupling step resulted in the formation of fewer levels of C3 compounds in the product, indicating that the present invention preferably uses methanol in the final step of the coupling reaction.

[0164] Example 6: Experiment on MeOH precursor gas flow

[0165] Experiments with ethanol plus a synthesis gas stream (2 moles H2: 1 mole CO) and experiments with ethanol plus a constant stream of CO2 and H2 (3 moles H2: 1 mole CO2) showed that the desired reaction occurred similarly to the presence of MeOH in the charge.

[0166] This example demonstrates that the same CO2 and H2 can be used in the coupling reaction.

[0167] Example 7: Analysis of gaseous effluent from ethanol coupling reaction

[0168] Analysis of the gaseous effluent from the reaction showed typical levels of 80% H2, 8% to 14% CO2, less than 5% CO (typically 1% to 2%), and small amounts of methane (about 2%), ethane and ethylene (less than 1%), propane, propylene, and other light components, totaling 100%. The presence of water reduced the CO content from 2% to less than 0.3%.

[0169] In this experiment, the H2 content was high, with a high H2 feed rate of 94% in the charge, which mainly led to a decrease in CO2 content to less than 2.5%.

[0170] Table 3: Results of experiments 8, 9, 22, 25 and 27

[0171] test 8 9 22 25 27 %EtOH 100 50 10 50 33,333 %MeOH 50 33,333 <![CDATA[%H2O]]> 0 33,333 <![CDATA[LHSV, hour -1 > 0,5 0,5 0,5 0,5 0,5 T,℃ 430 430 430 430 430 H2 / Fuel, NL / L 60 60 60 60 60 Product % EtOH 0,80 0,63 0,02 0,80 0,86 Product % MeOH 0,00 0,00 0,00 0,00 0,00 %DEE, DME and meOEt 22,20 2117 0,53 11,52 3,27 Alcohols and aldehydes C3 - - - 19,27 18,41 Light components 15,10 21,32 6,18 8,91 11,14 benzene 4,30 5,78 7,88 1,20 1,82 C7 7,78 9,86 4,92 5,44 6,56 Toluene 2,87 2,25 5,91 3,68 3,49 C8 5,16 7,62 4,24 6,41 7,68 EtBz 2,93 2,91 4,26 1,19 1,83 xylene 3,49 2,25 4,55 5,33 4,36 styrene 0,41 0,87 0,53 0,16 0,38 C9 7,76 10,07 11,84 7,86 9,03 C10 9,33 10,58 12,67 9,70 11,13 C11 4,81 6,63 6,84 7,29 8,07 C12 3,76 4,66 6,40 4,25 4,53 C13 3,44 3,96 5,49 3,06 3,28 C14 2,66 3,26 6,29 1,99 2,20 C15 1,03 1,24 2,62 0,75 0,70 C16 1,52 2,26 4,80 0,94 0,98 C17+ 0,69 1,59 5,73 0,40 0,36 Sum of C8 to C17+: %m 46,98 57,91 76,25 49,32 54,52

[0172] Table 4: Test results of reprocessing feed containing methanol

[0173]

[0174] The mass cumulative flow meter of the gaseous and liquid effluent from the reactor indicates that, typically, every 100 units of ethanol fed into the reactor produces 5 units of H2, 10 units of CO2, and about 1 unit of CO.

[0175] Example 8: Experiment with H2-free reactor feed

[0176] The tests with no H2 in the reactor feed showed similar results to those with H2.

[0177] Example 9: Benchtop reactor test of the hydrodeoxygenation reaction of ethanol coupling reaction products

[0178] The pre-sulfurized commercial NiMo catalyst was activated at 30 bar in an H2 atmosphere.

[0179] The mixture used was from the conversion test of ethanol conversion, and the mixture was from the product of Example 3.

[0180] LHSV is 0.5 hours -1 The temperature was 320°C, the pressure was 30 bar, and the H2 / fill ratio was 200 mL H2 / mL. Table 5 shows the analytical results of the test products. To account for the expected concentration effects caused by the conversion of ethanol to ethylene (detected in the gaseous effluent of the unit) and part of DEE, the comparative fill in the middle column was calculated.

[0181] There is a reduction in light components and benzene, as well as the elimination of oxygen-containing compounds, olefins, and dienes present in the charge, and an increase in the corresponding alkanes. Some characterized oxygen-containing compounds are shown as light components in the table, such as acetaldehyde, acetone, isopropanol, propanol, butanol, butyraldehyde, and 2-butenal, which are lost during the depressurization of the product in the hydrodeoxygenation reaction, resulting in a reduction in light components.

[0182] Because the catalyst has acidity, some alkylation of the more reactive diene with benzene may occur to form a heavier compound.

[0183] Table 5: Results of hydrodeoxygenation experiments using HDT catalyst

[0184]

[0185] Example 10: Hydrogenation reaction of alkyl cycloalkanes

[0186] The product obtained in Example 9 was used as the packing. Tests using a commercial aromatic compound hydrogenation catalyst supported on alumina containing 0.4% Pd and 0.2% Pt showed that at 250°C for 1.0 h… -1 At LHSV, pressure of 45 bar and H2 of 600 NL / L, almost all aromatic compound effluents from the sample were hydrogenated to alkylcycloalkanes.

[0187] It should be noted that although the invention has been illustrated by examples of the conversion of ethanol into alkyl aromatic compounds and alkyl cycloalkanes, those skilled in the art can modify and adapt it according to specific circumstances, provided that it is within the scope of the invention as defined herein.

Claims

1. A method for obtaining renewable aviation kerosene, characterized in that, Includes the following steps: (a) Feeding an aqueous solution of ethanol and carbon dioxide into the coupling step, wherein the concentration of the aqueous solution of ethanol is 10% to 50% ethanol in water. (b) The coupling step is carried out in at least one reactor with a coupling catalyst having an alkaline function in combination with a hydrogenation / dehydrogenation function; (c) At a pressure of 1 bar to 200 bar, a temperature of 150°C to 550°C, and for 0.1 hours -1 Up to 10 hours -1 The coupling step is performed under operating conditions of LHSV and H2 / charge ratio of 0 NL / L to 500 NL / L; (d) The liquid effluent from step (c) is sent to the processing step; (e) A processing step is performed in which a hydrodeoxygenation reaction and a hydrogenation reaction occur, thereby recovering the product having at least 50% C8+.

2. The method according to claim 1, characterized in that, The ethanol is derived from a renewable source.

3. The method according to claim 1, characterized in that, The carbon dioxide comes from sugar fermentation.

4. The method according to claim 1, characterized in that, The carbon dioxide comes from the recycling of the gaseous effluent from the coupling reaction.

5. The method according to claim 1, characterized in that, The feed also includes methanol, carbon dioxide, syngas, or mixtures thereof.

6. The method according to claim 1, characterized in that, The operating conditions for the coupling step are: pressure of 10 to 60 bar, temperature of 250°C to 450°C, and 0.2 hours. -1 Up to 5 hours -1 LHSV and H2 / charge ratio from 0 NL / L to 100 NL / L.

7. The method according to claim 6, characterized in that, The operating conditions for the coupling step are: pressure of 20 to 40 bar, temperature of 350°C to 450°C, and 0.5 hours. -1 Up to 2 hours -1 The LHSV and H2 / charge ratio of 20 NL / L to 50 NL / L.

8. The method according to claim 1, characterized in that, The coupling catalyst with hydrogenation / dehydrogenation function is selected from transition metals of Group VB, Group VIB, Group VIIIB, and Group IB, and exists in the catalyst in the form of oxides, carbonates, halides, phosphates, carbides, nitrides, or as a reducing metal.

9. The method according to claim 1, characterized in that, The coupling catalyst with hydrogenation / dehydrogenation function is selected from Cu, Ni, V, Cr, Mo, W, Fe, Ru, Co, Pt, and Pd, and exists in the catalyst in the form of oxides, carbonates, halides, phosphates, carbides, nitrides, or as a reducing metal.

10. The method according to claim 8 or 9, characterized in that, The coupling catalyst with hydrogenation / dehydrogenation function is copper supported on K-doped Al2O3.

11. The method according to claim 1, characterized in that, The coupling catalyst with basic function is selected from alkali metals and alkaline earth metals of Group IA and Group IIA in the form of oxides, hydroxides, phosphates, and carbonates, and may be supported or unsupported on a heterogeneous support.

12. The method according to claim 1, characterized in that, The coupling catalyst with basic function is selected from basic compounds, supported or unsupported on a heterogeneous support.

13. The method according to claim 11 or 12, characterized in that, The heterogeneous support is alumina, hydrotalcite, zeolite, silica, activated carbon, mixed oxides, spinel, alkaline clay, anion exchange resin, or alkaline organometallic compound.

14. The method according to claim 11 or 12, characterized in that, The heterogeneous support is a metal oxide.

15. The method according to claim 13, characterized in that, The alkaline clay is limestone, dolomite, magnesite, sepiolite, or olivine.

16. The method according to claim 14, characterized in that, The metal oxide is zinc oxide.

17. The method according to claim 11 or 12, characterized in that, The heterogeneous support is silicon dioxide-alumina.

18. The method according to claim 1, characterized in that, The operating conditions for the hydrodeoxygenation reaction step are: a pressure of 10 to 50 bar and a temperature of 200 to 350°C.

19. The method according to claim 18, characterized in that, The processing steps include performing a hydrodeoxygenation reaction under the following operating conditions: a pressure of 20 to 40 bar and a temperature of 250°C to 325°C.

20. The method according to claim 1, characterized in that, The hydrodeoxygenation catalyst for the treatment step is selected from solid-supported, Ni or Co-promoted, Mo or W sulfides.

21. The method according to claim 20, characterized in that, The solid is alumina, silicon dioxide, zeolite, hydrotalcite, mixed oxides, spinel, MgO, TiO2, ZnO, CeO2, phosphate, sulfonic acid resin, ZrO2, sulfated Zr, or carbon.

22. The method according to claim 20, characterized in that, The solid is silicon dioxide-alumina.

23. The method according to claim 20, characterized in that, The solid is activated carbon.

24. The method according to claim 1, characterized in that, The catalyst for the hydrodeoxygenation reaction is selected from single or mixed partial reducing metals supported on a solid.

25. The method according to claim 24, characterized in that, The metal is Pt, Pd, Ru, Ni, Cu, Mo, W, Co, Ir, Rh, Au, Ce, Fe, Mn, Ga, Pb, or Bi.

26. The method according to claim 24, characterized in that, The solid is alumina, silicon dioxide, zeolite, hydrotalcite, mixed oxides, spinel, MgO, TiO2, ZnO, CeO2, phosphate, sulfonic acid resin, ZrO2, sulfated Zr, or carbon.

27. The method according to claim 24, characterized in that, The solid is silicon dioxide-alumina.

28. The method according to claim 24, characterized in that, The solid is activated carbon.

29. The method according to claim 24, characterized in that, The catalyst for the hydrodeoxygenation reaction is a partially reduced metal oxide supported on a porous solid.

30. The method according to claim 29, characterized in that, The metal oxide is MoO3, RuO2, IrO2, PdO, Rh2O3, SnO2, ZnO, VO2, TiO2, CeO2, CuO, Ag2O or Au2O3.

31. The method according to claim 24, characterized in that, The support used for the catalyst in the hydrodeoxygenation reaction is oxyphilic.

32. The method according to claim 31, characterized in that, The support used for the catalyst in the hydrodeoxygenation reaction is alumina, TiO2, or ZrO2.

33. The method according to claim 1, characterized in that, The processing steps include a hydrogenation reaction using a hydrogenation catalyst selected from the following: Ni or a noble metal supported on alumina, silica-alumina, zeolite, activated carbon, Ti, or clay.

34. The method according to claim 1, characterized in that, The processing steps include a hydrogenation reaction using a catalyst selected from the following: Ni or a noble metal supported on an alkaline oxide.

35. The method according to claim 33 or 34, characterized in that, The precious metal is Pt, Pd, Ru, Rh, or Re.

36. The method according to claim 1, characterized in that, The processing steps comprise a single step of hydrodeoxygenation plus hydrogenation, wherein the catalyst used for the hydrodeoxygenation reaction and the catalyst used for the hydrogenation reaction are combined in the same catalyst.

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