BRPI0611343A2 - processes for catalytic conversion of lignin to liquid biofuels - Google Patents

Abstract

PROCEDURES FOR CATALYTIC CONVERSION OF LIGNIN IN LIQUID BIOFUELS Processes for converting lignin into liquid products such as biofuels and fuel additives are disclosed and described (Figure 1). A process for converting a lignin material to biofuels may include subjecting the lignin material to a base catalyzed (stage 1) depolymerization reaction to produce a partially depolymerized ligfine. Partially depolymerized lignin may then be subjected to a partial hydrodeoxygenation / stabilization reaction (stage II) to form a partially hydrodeoxygenated product. After partial deoxygenation, the partially deoxygenated product can be reacted in a refining step (TS stage) to form a biofuel. Each of these reaction steps can be performed in a single or multiple step, depending on the process design. The production of a partial hydrodeoxygen intermediate product and subsequent reaction thereof can significantly reduce or eliminate reactor blockage and catalyst coking. A variety of useful biofuels such as fuels, fuel additives, and the like can easily be produced from renewable lignin materials in an improved conversion process.

Description

"PROCESSES FOR CATALYTIC CONVERSION OF LIQUID FUELS"

Field of the invention

The present invention relates generally to the conversion of biomass into fuels, fuel additives and other commercially useful products. More particularly, the present invention relates to a multi-step catalytic process for producing hydrocarbon products from lignin.

BACKGROUND OF THE INVENTION

The current market for power and fuel conductors is largely driven by high oil and natural gas prices resulting from depletion of easily accessible deposits, a growing demand caused by the development of new emerging market economies, and mounting environmental concerns. Consequently, these growing energy demands will require significant restructuring and / or replacement of a large part of fossil fuels with renewable energy technologies with biomass-based energy technologies. Mature technologies are available to produce a variety of commodities including transportation fuels and chemical building blocks from wood, agricultural crops, municipal solid waste, landfill gas, etc., which will allow this new energy sector to develop it. This emerging sector serves as a network of bio-refineries (a-petrochemical refinery dialogues) and represents a group of integrated processing facilities, perfect for the environment. In these facilities biomass components are separated and converted into valuable intermediates and end products, including biofuels, bioenergy, and other bio-products.

Cellulose and lignin represent two of the most prominent renewable carbon sources. Lignin, second in relation to cellulose as the most abundant renewable carbon source on Earth, is a phenolic biopolymer rich in amorphous three-dimensional energy that is deposited on all vascular plants and provides rigidity and resistance to their cell walls. The polymeric structure of lignin is mainly composed of three phenylpropanoid building units: p-hydroxy phenyl propane (Structure I), guaiylpropane (Structure II), and syringyl propane (Structure III) interconnected by carbon and etheric bonds with carbon. good. Generally, in unprocessed lignins, two thirds or more of these bonds are ether bonds, while the remaining bonds are carbon-carbon bonds.

<formula> formula see original document page 3 </formula>

Different types of lignin differ significantly in the ratio of these monomers. Inherent in its molecular nature, the lignin biomass component can potentially be converted directly into liquid fuels, for example, high octane alkyl benzene / or aromatic ether gasoline blend components.

Currently, a limited supply of lignin is available as a byproduct of the pulp and paper industry. However, in the near future, large quantities of lignin waste material will be available from biomass-in-ethanol processes and other associated refineries and processes. To date, in typical bio-refinery process projects, lignin appears as a residual material with limited opportunities for use.

Other sources of lignin material may include agricultural and waste products, municipal waste, and the like.

Beneficiation of lignin residue by a catalytic conversion process into high value fuels and fuel additives has been sought to increase the competitiveness of biofineries technologies. Numerous efforts on lignin conversion have included a number of single-stage processing methods including hydrocracking, cracking, hydrogenation, hydrotreating, liquefaction in hydrogen donor solvents, and similar ones. However, to date, these approaches have had limited success for a variety of reasons.

Over the past few years, several studies have been initiated to develop two-stage processes for making liquid fuels and fuel additives from lignin. These studies provided a significant initial basis for identifying commercially useful processes for converting lignin into valuable high deoctana biofuels. Two methods are of specific interest and are described in US Patent Nos. 5,959,167 and 6,172,272, each of which is incorporated herein by reference in its entirety.

One such method is described as a two-stage lignin to gasoline (LTG) process. A first step involves depolymerization of lignin feed base catalyst (BC) into a reaction medium such as an alcohol followed by catalytic hydroprocessing (HPR). At the BCD stage of the process, lignin is partially depolymerized, mainly by solvolysis of etheric bonds, to ether-soluble mono-, bi- and trimeric phenolic moieties, and some hydrocarbons. In the second stage of the procedure, hydroprocessing (HPR), the BCD product undergoes simultaneous hydro-deoxygenation (HDO) and hydrocracking (HCR) to completely remove remaining oxygen and break inter-aromatic C-C bonds. The general procedure for BCD-HPR provides a low sulfur octane elevated hydrocarbon petrol additive consisting of a mixture of C7 -C1 alkyl benzene, and some C6 -Cn mono-, di-, tri and polyalkylated naphthenes and C5 paraffins - Cn (mostly multi-branched).

The second two-stage method is a delignin-in-aromatic ethers (LTE) process and is designed primarily for the production of partially oxygenated gasoline or for the selective production of C7 - Cn methoxy benzene as high octane additives. This process utilizes a similar two-stage procedure as the first process briefly described above. In the first stage, lignin is subjected to a white base catalyst (BCD) depolymerization in supercritical alcohol as a reaction medium. This step is then followed by non-deoxygenating hydrotreating / mild hydrocracking (HT), and a subsequent etherification (ETR) of the intermediate phenolic product to provide a reformulated partially oxygenated gasoline. The resulting agasoline is typically a mixture of (substituted) phenyl methyl ethers (mixture octane number, 124-166; boiling point, 154-195 ° C) and methyl cycloalkyl ethers, C7 -C10 alkyl benzene, C5 paraffins - Cio (mainly multi-branched), and polyalkylated cycloalkanes.

Unfortunately, these two-stage processes may suffer from excessive catalyst coking and formation of polymeric solids that tend to clog the reactors. In addition, alcohol-based solvents tend to alkylate with reagents and oxidize to acetic acid which reduces yields and makes elimination of by-products more difficult.

As a result, research continues to develop processes for converting lignin into more valuable products that are economically viable. Many challenges still remain to provide useful product yields without sacrificing process reliability.

SUMMARY OF THE INVENTION

It has been recognized that it would be advantageous to develop processes which allow the conversion of lignin into more valuable products such as biofuels and fuel additives with improved yields and acceptable processing conditions.

According to one aspect of the present invention, a process for converting a lignin material to biofuels may include subjecting the lignin material to a base catalyzed depolymerization reaction to produce a partially depolymerized lignin. Partially depolymerized lignin may then be subjected to a partial hydrodeoxygenation / stabilization reaction to form a partially hydrodeoxygenated product. Following hydrodeoxygenation, the partially hydrodeoxygenated product may be reacted in a refining step to form a biofuel. Each of these reaction steps can be performed in single or multiple steps, depending on the process design.

In a detailed aspect of the present invention, base-catalyzed depolymerization sandation may include dissolving the lignin material in a base-catalyst in the presence of a polar solvent. The dissolved ligatin material may then be subjected to sufficient reaction conditions to partially depolymerize the lignin material. Partially polymerized phenolic lignin products may be recovered and optionally separated from other products as part of the base catalysed polymerization reaction.

In more detail, the base catalyst may be NaOH, KOH, Ca (OH) 2 / Mg (OH) 2, and mixtures thereof, although other base catalysts may be used. Similarly, several polar solvents may be used; however, water is currently preferred. In addition, in one aspect, the base catalyzed depolymerization reaction may be performed under conditions that are substantially free of alcohols.

In another detailed aspect, the partial hydrodexygenation / stabilization reaction may include exposing the partially depolymerized lignin to a solid catalyst at a temperature below about 300 ° C, for example about 2000 ° C to approximately 300 ° C.

A variety of solid catalysts may be useful for the partial hydrodeoxygenation / stabilization reaction. Typically, the solid catalyst may include a support material and a catalyst material. Preferably, the support material may be a nonacidic material such as activated carbon, silicon dioxide, aluminum oxide, or combinations thereof. The choice of material for the catalyst material portion of the solid catalyst may also be an important consideration. Non-limiting examples of partially suitable catalyst material may include Co-Mo, Rh-Mo7 Ru-Mo, Pt-Mo7 Pd-Mo, and combinations, alloys or composites thereof.

In another detailed aspect of the present invention, partial hydrodeoxygenation / stabilization may occur under conditions sufficient to convert more than about 95%, and preferably more than approximately 98% of methoxy phenols and benzenediols to base products. phenol having a single oxygen fraction.

Still another aspect of the present invention includes performing any number of refining steps designed to obtain a specific biofuel product. For example, the refining step may include a hydro-deoxygenation reaction, a mild hydrocracking reaction, an etherification reaction, a hydrogenation reaction and / or combinations thereof.

The refining step may be a hydro-processing reaction that includes a hydrodeoxygenation step and a subsequent hydrocracking step. Although process conditions may vary, the hydroprocessing reaction may occur at a temperature of approximately 250 ° C to approximately 400 ° C, and in some cases from approximately 320 ° C to approximately 450 ° C.

Alternatively, the refining step may include a mild hydrocracking reaction followed by an etherification reaction.

In yet another alternative embodiment, the partially hydrodeoxygenated product may be fractionated into a first monomer fraction and a second oligomeric fraction (e.g., intensively substituted dimers, trimers, and rings). The first low molecular weight fraction may be treated in an etherification reaction with methanol or e-tanol to form aromatic ethers which are particularly useful as fuel additives. Similarly, the second high molecular weight alkyl phenol moiety can then be treated in a hydroprocessing reaction and an optional hydrogenation reaction to form biofuels such as aromatic gasolines and / or jet fuels.

Additional features and advantages of the invention will be apparent from the detailed description illustrating, by way of example, features of the invention.

BRIEF DESCRIPTION OF DRAWINGS

Aspects of the invention may be better understood with reference to the following drawings.

Figure 1 is a flow diagram of a three stage process for converting lignin to dealkyl benzene gasoline mixing components according to one embodiment of the present invention.

Figure 2 is a flow diagram of a four stage process for converting lignin to aromatic ether gasoline mixing components according to one embodiment of the present invention.

Figure 3 is a flow diagram of an integrated process for converting lignin into liquid-transporting fuels according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT (S)

Before specific embodiments of the present invention are disclosed and described, it should be understood that this invention is not limited to the specific process and materials disclosed herein since they may vary to a certain extent. It is also to be understood that the terminology used herein is used for the purpose of describing specific embodiments only and is not intended to be limiting, since the scope of the present invention will be defined only by the appended and equivalent claims thereto.

In describing and claiming the present invention, the following terminology will be used.

The singular forms "one", "one", and "o, a" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "one step" includes reference to one or more such steps.

As used herein, "reaction" is intended to encompass single and multi-step reactions which may be direct reaction of reactants in products or may include one or more intermediate species which may be stable or transient.

As used herein, "biofuels" refers to any fuel, fuel additive, a-romantic and / or aliphatic compound derived from a biomass particulate material such as lignin.

As used herein, "lignin" and "lignin material" are used interchangeably and refer to a biomass material that is a three-dimensional, amorphous phenolic-rich phenolic biopolymer. Lignin is typically deposited on almost all vascular plants and provides stiffness and resistance to the walls of their cells. As mentioned above, the lignin polymeric structure is composed primarily of three phenyl propanoid building units interconnected by etheric and carbon-carbon bonds. Non-limiting examples of lignin material may include agricultural lignin, wood lignin, municipal waste derived lignin, Kraft lignin, organo-solve lignin, and combinations thereof. Wood lignin is currently a renewable and widely available resource that may be particularly suitable for use in the present invention.

As used herein, "oxygen fraction" refers to any oxygen-containing substituent for an aromatic ring or other major group. Typically, deoxygen fractions present in the compounds of the present invention may include hydroxyl groups, however other groups such as methoxy, alkoxy, carboxy, and the like may also be included. Compounds containing a single oxygen fraction are stabilized, or in other words, are not polymerizable under identified process conditions, for example phenol or other aromatics containing a single oxygen fraction.

In contrast, compounds containing two or more o-oxygen fractions tend to be polymerizable to form undesirable coking, for example, methoxy phenol, benzenediol, and the like.

As used herein, "non-acidic support material" refers to a solid catalyst support that is non-acidic. In terms of a solid, the terms pH and pKa are generally not useful because these terms are fluid condition measurements. As such, the acidity of a solid can be measured as a complex function expressed as a Hammett indicator. Effective Hammett indicator values for catalyst support materials of the present invention are currently unknown. However, in the context of the present invention, non-acidic support materials for SPHDO (partial stabilization / hydrodeoxygenation) are those which are substantially free of sufficient acidic sites to avoid coking poisoning. Conventional catalyst support materials are most often provided as acidic support materials; however, non-acidic support materials may be formed or prepared by adjusting the method of preparation, sub-sequential base treatment or other methods available for re-viewing or neutralizing any acidic sites. For example, alumina support materials may be acidic or nonacidic depending on the method of preparation or subsequent treatment.

As used herein, "substantial" when used with reference to a quantity of a material, or a specific characteristic thereof, refers to an amount that is sufficient to provide an effect that the material or characteristic was intended to provide. The exact degree of allowable deviation may in some cases depend on the specific context. Similarly, "substantially free from" similarity refers to the lack of an identified element or agent in a composition. Particularly, elements that are identified as being "substantially free of" are entirely absent from the composition, or are included only in amounts that are small enough to have no measurable effect on the composition.

As used herein, the terms "partially" or "partially" when used with respect to the phrase "partial stabilization / hydrodeoxygenation" or "SPHDO" refer to the percentage of oxygen fractions eliminated from the final products of the catalyzed depolymerization reaction lignin porbase (BCD). The percentage of total oxygen removed from the BCD end product may range from 30% to 60%, preferably an average around 50%. As such, approximately 95% and preferably more than approximately 99% of polymerizable BCD end products (i.e. products having multiple oxygen fractions) can be converted into stabilized products having single oxygen fractions. "Partial" hydrodeoxygenation occurs when the methoxy and / or hydroxyl groups are removed from the methoxy phenol or benzenediol compound to provide single oxygen-containing phenolic compounds.

As used herein, "refining step (s)" refers to any single reaction or combination of reactions or reaction steps that processes the partially hydrogenated products of the SPHDO reaction into a biofuel. Examples of refining steps include but are not limited to hydroprocessing reactions such as hydro deoxygenation reactions, white hydrocracking reactions, etherification reactions, hydrogenation reactions, and combinations thereof.

As used herein, a plurality of items, structural elements, composition elements, and / or materials may be presented in a common list for convenience. However, these lists must be interpreted as each member of the list being individually identified as a separate and unique element. Thus, no individual element of this list should be interpreted as a de facto equivalent of any other element of the list solely on the basis of its presentation in a common group without any indication to the contrary.

Concentrations, quantities and other numerical data can be presented here in a strip format. It should be understood that such a range format is used simply for convenience and brevity and should be interpreted flexibly as including not only the numerical values explicitly referred to as the range boundaries, but also including all individual or sub-numeric values. ranges covered in that range as if each valornumeric and subband were explicitly quoted. For example, a weight range from approximately 1% to approximately 20% should be interpreted as including not only explicitly cited concentration limits of approximately 1% to approximately 20%, but also including individual concentrations such as 2%, 3 %, 4%, and -sub-ranges like 5% to 15%, 10% to 20%, etc.

In accordance with the present invention, biofuels can be produced using a three step process including base catalyzed depolymerization, partial hydrodeoxygenation / stabilization, and a refining step. Earlier approaches, subsequent steps of both LTG processes (US Patent No. 5,959,167) as well as LTE (US Patent No. 6,172,272), the BCD product was treated in steps of hydroprocessing (HPR) and selective hydrocracking ( HC), respectively with acidic catalysts at temperatures above 350 ° C. This approach may be useful in some circumstances; however, the high temperatures required may result in a reduction in reliability during scaling and extended production strokes. This application is related to US provisional patent application serial number 60 / 677,662, filed May 2, 2005, which is hereby incorporated by reference.

Typically, lignin BCD products are mainly phenolic compounds including mono-, dipolyalkylated phenols, methoxy phenols, benzenediols, and some polyalkylated benzenes (e.g., 2-10%) and dimeric aromatic non-phenolic compounds. and trimeric. Such a product, if used in the LTG process, requires additional beneficiation, for example oxygen removal through a deoxygenation process and simultaneous (using a hybrid catalyst) or consecutive hydrocracking, which results in higher chemical stability and increased H / H ratio. C, heating value, etc. The BCD process tends to produce a relatively high content of very reactive, thermally unstable benzenediols and methoxyphenols. These unstable phenols tend to undergo rapid polycondensation which results in solid buffers in HDO reactors during high temperature (> 300 ° C) HDO process. In addition, a relatively strong interaction of such typical HDO catalyst support acid composites (emalumin and other acidic supports) results in significant catalyst coking. Additionally, the presence of a strongly acidic hydrocracking (HCR) cocatalyst component results in rapid catalyst coking and subsequent deactivation of the HCR catalyst. Similar conditions were observed in the MH step of the LTE process.

In accordance with the present invention, a low temperature partial stabilization / hydrodeoxygenation (SPHDO) treatment may be considered prior to the HPR process for alleviating the catalyst deactivation and polymerization problem. Typically, the treatment of SPHDO may be performed in a low temperature range (e.g., 200 ° C - 400 ° C, and often less than approximately 300 ° C, depending on the catalyst); however, other temperature ranges may be appropriate depending on the associated reaction kinetic catalyst. The process of treating SPDO may result in the conversion of methoxy phenols to benzene nodiols and methane, and then subsequently eliminating an OH group from benzene diols to produce phenols. In addition, the elimination and / or reduction of surface acid sites from an SPHDO catalyst support can prevent undesirable coke buildup. As an illustration in Equation I, a reaction scheme for partial stabilization / hydrodesoxygenation of guaiacol (2-methoxy phenol) is shown.

<formula> formula see original document page 17 </formula>

(Equation 1)

The bond dissociation energy of the aromatic carbons-deoxygen atom in phenols and ethers is approximately 84.4 kJ / mol greater than that of an aliphatic carbons-deoxygen atom. This may at least partially explain why removing a methylate group from a methoxy group is easier than removing whole methoxy groups. Methane production is very low and is predominantly CO2, with some H2 and hydrocarbons. This product can be useful as a fuel source and can be burned on site as an additional heating source. The partial stabilization / hydrodeoxygenation reactions of the present invention may proceed to remove polymerizable fractions in order to reduce or prevent the formation of undesirable polycondensation products.

The resulting phenolic SPHDO products can then be subjected to a variety of hydroprocessing (HPR) refining steps without formation of substantial condensation products. Thus, the SPHDO step can allow for reduced catalyst coking, reduced reaction temperatures and reduced costs, as well as allowing subsequent high temperature (> 300 ° C) hydroprocessing (HPR), ie substantially complete hydrodesoxygenation (HDO). ) and hydrocracking (HCR) to break interaromatic DC connections. HDO and HRC reactions can be performed separately or in a single processing step. Careful selection of HCR and HDO catalysts and process conditions is desirable for selective conversion of BCD-SPHDO product to a mainly aromatic monomer product. As a general matter, HDO catalysts can be chosen based on low hydrogenation activity and HCR catalysts based on low acidity optimization and low hydrogenation activity. Aromatic hydrogenation during these reactions should be minimized by careful choice of catalyst and associated temperatures.

In accordance with the present invention, specific attention may be given to the preparation of e-fused SPHDO catalysts which have high activity and resistance to deactivating effects. In one aspect, an SPHDO catalyst may be prepared by altering typical HDO catalysts. For example, an acidic alumina support may be substituted with alternative nonacidic supports such as nonacidic alumina (neutralized with NaOH, KOH, etc.), carbonative, silica, and composites thereof. Alternatively, or in addition to the above, noble metals may be incorporated into the catalyst step. In yet another alternative, SPHDO catalysts such as supported or unsupported transition metal carbides may be useful. Non-mitigating examples of suitable SPHDO catalysts may include but are not limited to supported or unsupported transition metal nitrides, supported or unsupported transition metal carbides, or combinations thereof. Examples of transition metal nitrides include, but are not limited to, NV; Mo2N, TiN, and combinations thereof. Examples of transition metal carbides include but are not limited to WC, Mo2C, VC, and combinations thereof. As a catalyst for the SPHDO step, acidity can be an important factor in determining efficacy. In particular, SPHDO catalyst support materials may be nonacidic such that the reaction kinetics of catalytic stabilization reactions are controlling for non-catalytic coking and repolymerization reactions. As temperatures rise, non-catalytic coking reactions tend to become controlling. For example, CoMoM2O3 non-acidic SPHDO catalysts typically have a maximum operating temperature of approximately 300 ° C before non-catalytic coking reactions become controlling, which leads to catalyst poisoning. Other SPHDO catalysts and temperature conditions may vary.

However, at least some minor repolymerization reactions may be desirable since such species in smaller amounts may act as catalytic promoters for desirable SPHDO oxygen group elimination reactions.

Noble metal containing catalysts are generally more active and selective for SPHDO than standard HDO catalysts. Another important advantage of these catalysts is their ability to perform selective direct elimination of entire methoxy groups resulting in only one oxygen atom (phenols) as a major product. In addition, such catalysts may be less active for undesirable reactions, for example, coking and aromatic ring hydrogenation. Higher active catalysts can perform acceptably well at a lower temperature range where coking reactions proceed more slowly. In addition, application of active carbon or SiO2 as a SPHDO catalyst support can provide reduced coking. As a general guideline, the SPHDO catalyst and support material may be non-acidic and substantially free of sufficient acidic sites to avoid coking poisoning at specified operating temperatures.

Several examples of specific applications of the present invention are described in detail below with respect to an increased catalytic lignin conversion process as an increased lignin to gasoline (ELTG) process; an increased aromatic ether lignin process (ELTE); and an integrated liquid fuel lignin process (ILTF). Each of these processes includes the same basic lignin conversion stages, for example, BCD andSPHDO. Specific operating conditions and additional stages as refining steps may depend on the desired product.

Increased Gasoline Lignin (ELTG) Process

A flow diagram of the increased delignin conversion process for producing aromatic egasoline gasoline additives in a three stage procedure is shown in Figure 1. In the first stage of the process, a lignin feed is subjected to base catalyzed depolymerization (BCD) of a partially stripped product. In the second stage, the partially depolymerized BCD product may be subjected to a low temperature partial stabilization / hydrodeoxygenation (SPHDO) process. During the third stage of the process, the SPHDO product may be hydroprocessed to obtain a biofuel product including aromatic rich gasoline and a higher molecular weight fraction. The specific fuel biofuel composition may depend heavily on the HPR processing conditions. The last mentioned fraction may optionally be subjected to aromatic ring e-exhaustive hydrogenation to obtain valuable naphthenic kerosene (NK). Each of these three steps is discussed in more detail below.

In the first stage of the process a delignin material can be dissolved in an aqueous base catalyst solution. Although specific process conditions may vary, typical reaction temperatures may range from about 230 ° C to about 350 ° C. Similarly, autogenic pressure from approximately 1000 to approximately 161.71 kgf / cm2 may be useful. The BCD reaction can be generically operated at a feed rate of delignin material at net hourly space velocity (LHSV) from about -0.5 to about 6.0 h-1. Alkali metal and alkaline earth metal hydroxides can Non-limiting examples of suitable base catalysts may include NaOH, pure KOH, Ca (OH) 2 / Mg (OH) 2, and mixtures thereof In one aspect, the preferred liquid medium is: It is water, however methanol and / or ethanol may also be used as well as combinations of water, methanol, and / or ethanol.

Preferably, a continuous stirred tank reactor (CSTR) may be used with respect to the BCD process. However, any reactor that reduces or eliminates precipitated buildup may be used, for example, any stirred reactor, and the like. Precipitates may appear with respect to the reduction in base catalyst concentration during the BCD process and may also cause reactor clogging.

The primary solid / liquid portion of the BCD derivation product may be precipitated by acidification with CO2e and / or other acidic species such as, but not limited to, hydrochloric acid, sulfuric acid, phosphoric acid, and the like. As an added benefit, phosphoric acid washing may also result in a fertilizer byproduct. The precipitated BCD product can then be washed and dried. The remaining non-precipitated BCD water-soluble product (mainly benzenopolyols such as benzenediol) can be extracted from the water solution with diethyl ether and added to the acid-precipitated primary water-insoluble portion of the product. Alternatively, the extracted water-soluble BCD product can be used as a source of valuable biochemicals as it is. The dry BCD product can be diluted in a temperature fixed from about 100 ° C to about 150 ° C with any number of liquid vehicles as selected self-produced fractions of SPHDO and / or HPR products. Insoluble high molecular weight components may be separated by filtration or centrifugation and desalted. These insoluble components can be used as feed in the SPHDO process. A suitable desalination treatment similar to those applied in crude oil treatment may be useful to prevent corrosion and poisoning effects of sodium and calcium salts absorbed in the solid BCD product. In still an alternative, low-weight-fraction fraction extracted with diluted ether from the BCD product may be used as feed in the SPHDO process.

During the early period of the previous studies of delignin partial base catalyzed depolymerization (BCD) the catalyst examined in the process was NaOH (KOH eCsOH were also tested), while methanol or supercritical ethanols were used as solvents and reaction media. Batch reactor experiments with alcoholic solvents showed a high degree of ligin depolymerization (up to 98% by weight of an ether soluble product). However, during the BCD process, extensive ring methylation (e-tylation), and partial conversion of methanol and ethanol to formic and acetic acids, respectively, occurred. These reactions resulted in the formation of undesirable (> C9) higher molecular weight phenols, and loss of an alcoholic solvent due to neutralization of the base catalyst with the emergent acids. This resulted in a relatively high decatalyst / lignin ratio to obtain a high level of lignin depolymerization. To eliminate these problems and improve process economics, alcoholic solvents were replaced with water as an inert, non-alkylating, and cheaper solvent.

Using a packaged flow reactor system, water as solvent, and NaOH as catalyst, lignin can be converted up to 60 - 80% by weight of ether soluble product at moderate temperature and short reaction times. . Experiments using a NaOH-Ca (OH) 2 (low NaOH) system in a batch micro-reactor showed significant resistance to NaOH catalyst neutralization. In addition, Ca (OH) 2 contributes mainly to the BCD reaction as CO2 and weak organic acid purifier.

Hydrolysis of etheric bonds in the delignin structure in the BCD process results in the formation of significant amounts of monomeric phenols and benzenediols and alkoxyphenols which are also valuable co-chemicals.

The partially depolymerized lignin BCD product or its ether layer, after being diluted with a part of the fraction of the self-produced phenolic product and / or high boiling aromatic alkyl, may be subjected to a process. stabilization / hydrodesoxygenation (SPHDO) at low temperature. Such a process may include the conversion of unstable methoxy phenols and benzenediols to a stable phenolic product in the catalysts as discussed herein as catalytic CoMo supported catalysts and active carbon. Such catalysts may also be used in the basic form as well as those modified by neutralizing support surface acidity (alumina) and / or introducing additional noble metal promoters such as Pt, Pd, Ru and Rh.

Currently preferred catalysts of this type are sulfur-based noble metal promoted MMo / C systems, where M-Rh, Ru and Pt. Sulfation of catalysts can be accomplished by treatment with a mixture of hydrogen and hydrogen sulfide. These noble metal-containing catalysts demonstrate high HDO activity and higher selectivity than phenols. An important element of carbon-supported catalyst is the low cost of carbon support and the ability to recover precious metals from catalysts simply by burning carbon rather than more expensive recovery or refining processes.

Currently preferred processing conditions for the SPHDO reaction are a temperature of approximately 200 ° C to approximately 300 ° C, a residence time of approximately 5 to approximately 15 minutes, H2 pressure of approximately 500 to approximately 140.62kgf / cm2. Although not required, the entire volume of the SPHDO product is typically subjected to the hydroprocessing (HPR) refining step.

HPR reaction courses with BCD-SPHDO as a feed may be performed in a single step procedure, or as a sequence of HDO and HCR reactions separated to obtain an aromatic rich product consisting mainly of C7 - Cn alkyl benzene. HDO (C0M0 / AI2O3) and HCR (CoMo / Al203-Si02 which can be amorphous or crystallized, ie, zeolite) catalysts are preferred because of their high activity and selectivity in terms of obtaining oxygen-free final HPR product. monomeric, desirable. Other useful catalysts may include but are certainly not limited to, ΜΜο / γ-Α1203 (HDO) and MMo / Al203-Si02 (HCR) where M = Ru, Re, Cr, or Fe (and combinations with Co) as well as carbides and nitrides thereof. This process requires careful selection of optimal reaction conditions and catalysts to minimize aromatic ring hydrogenation reactions in order to maximize monomeric aromatic compounds that are desirable as a final biofuel product of the process of the present invention. The undesirable ring hydrogenation of C7 -C10 alkyl benzene in corresponding naphthenes is easily controllable by processing conditions and can be minimized or even substantially eliminated.

Careful selection of HDO and HCR catalysts and process conditions is desirable for selectively converting BCD-SPHDO product to a primarily aromatic, monomeric product. As a general matter, HDO catalysts may be chosen based on low hydrogenation activity and HCR catalysts based on acidity optimization and low hydrogenation activity.

Aromatic ring hydrogenation during these reactions should be minimized by careful choice of catalyst and associated temperatures. For example, the use of Ni in an HDO catalyst is highly active but also tends to result in high yields of cyclohexane and other hydrogenated products. Generally, HDO caps can be neutral, slightly acidic or even slightly basic with substantially neutral send preference. Specifically, HDO catalysts may be chosen to allow for exhaustive hydrodeoxygenation without coking poisoning. In contrast, materials supporting HCR (or MH) catalysts are generally acidic or strongly acidic enough to provide cracking without also causing excessive coking.

Higher molecular weight fraction components such as alkylated naphthalenes, alkylated tetralines, alkylated damages, alkylated biphenyls and polyalkylated benzenes of the BCD-SPHDO-HPR product (boiling point: 205 ° C) may optionally be subjected to exhaustive hydrogenation, providing high value naphthenic kerosene as shown in Stage III of Figure 1.

Enhanced Lignin Process in Aromatic Ethers (ELTE)

Referring now to Figure 2, the BCD eSPGDO stages of the ELTE process may be almost the same as that presented for the ELTG process of Figure 1. The BC-SPHDO product may be subjected to subsequent mild hydrocracking and methanol etherification.

As previously noted, the Iiginine BCD-SPHDO results in a high yield but incomplete depolymerization of the polymeric structure of the feed. For example, in addition to the main product consisting of monocyclic phenols, there are significant amounts of intermediate phenolic oligomers. To increase the amount of the monomer product, a mild hydrocracking procedure for the crude BCD product (designated as a ΜΗ procedure) in the presence of solid superacid catalysts is shown in Figure 2 as Stage III. Such an additional MH treatment can effectively depolymerize lignin by selective C-C cleavage of residual intermediate oligomers to produce the desired monomeric phenols. Although processing conditions for the treatment of MH may vary, currently preferred processing conditions are a reaction temperature of from about 200 ° C to about 400 ° C, a residence time of about 5 to about 30 minutes, and a pressure (H2) from approximately 70.31 to approximately 126.55 kgf / cm2. Non-limiting examples of strongly acidic catalysts suitable for MH treatment step may include Pt / WO42 VZrO2, heteropoly acids and their salts (supported and unsupported), FeCl3. 6H20, and the like.

As shown in Figure 2 in Stage IV, a mixture of light monomeric phenols in the BCD-SPHDO product may be etherified with methanol. Preferably, etherification aeration may be performed at a reactor temperature of from about 200 ° C to about 400 ° C and an autogenous pressure of from about 100 to about 140.62 kgf / cm2.

Any suitable catalyst may be used in the etherification reaction. Suitable catalysts podemincluir, but are not limited to, heteropolyacids assumed tados or salts thereof, potassium benzoate, Cs-P / Si02, SO42 "/ MnOxMl2O3, SO42VMoOxMl2O3, SO42VWOxMl2O3, SO42VCrOxMl2O3, SO42VCeOxMl2O3 and the like. Typically methanol can will be used as the Any flow-reactor system that allows for continuous drying of the recycled spillage mixture can be used.The ELTG process of the present invention provides several benefits over the previously available processes.The largest portion of oxygen present in the BCD product. -SPHDO can be preserved which eliminates the need for expensive, additional dehydrogenation steps.Also, oxygen remains incorporated into a larger portion of the final high octane benzene alkoxy gasoline components, so there is substantially no external oxygen-containing additives as recommended by the Clean Air In addition, the final total ELTG product, including hydrocarbons, is expected to have octane numbers of approximately 130. As a result, these products can be conveniently used as a blending additive (for example, in oil-derived gasolines having lower octane numbers. ) to generate Premium reformulated gas-solines that have improved combustion characteristics.

Liquid Lignin Integrated Fuel Process (ILTF)

In another aspect of the present invention, the ELTG and ELTE processes may be integrated into a single process. The final ILTF products derived from such an integrated process may include the products of each of the ELTG and ELTE processes as alkyl benzene gasoline. , naphthenic kerosene and aromatic ether gasoline additives.

As discussed above with reference to Figures 1 and 2, a base catalyzed depolymerization reaction may be used to produce a partially demerged lignin product. Preferably, the base catalyzed depolymerization reaction may be carried out substantially only with water as the solvent and reaction medium. After BCD sandblasting, a low temperature stabilization / hydrodeoxygenation (SPHDO) and fractionation (optional) process of C6 - C9 alkyl phenols from the SPHDO product can be performed. High temperature hydroprocessing (HPR) reactions of the SPHDO product can provide rich emaromatic gasoline as a primary product. In addition, exhaustive hydrogenation of the higher molecular weight fraction of the HPR product containing alkylated naphthalenes, alkylated tetralines, alkylated indans, alkylated and benzenospolyalkylated biphenyls, providing high value naphthenic kerosene. Etherification of Cg - Cg alkyl phenols from the SPHDO product may be carried out to produce aromatic ethers (alkylated benzoyl alkoxy). Each of these steps was previously discussed with respect to figures 1 and / or 2.

A flow diagram of the integrated delignin conversion process (ILTF) for the production of aromatic gasoline, jet / rocket propellant and aromatic ethers in a multistage procedure is shown in Figure 3. In the first stage of the process, lignin material may be subjected to base catalyzed depolymerization (BCD) with water, optionally methanol or ethanol, as a solvent and reaction medium. The total partially depolymerized lignin product or its ether extract, after being diluted with part of the SPHDO product and / or the elevated boiling fraction of the alkyl aromatic product, may be subjected to a partial stabilization / hydrodeoxygenation process (SPHDO). ) low temperature. This SPHDO process involves converting unstable methoxy phenols and benzenediols into a more stable phenolic product. During a third stage of the process, the partially hydrodeoxygenated SPHDO product may be subjected to hydroprocessing (HPR) reactions to obtain aromatic rich gasoline. Higher molecular weight compounds, for example alkylated naphthalenes, alkylated tetralines, alkylated indanes, alkylated biphenyls and polyalkylated benzenes are produced as a hydroprocessing product. Yields and product types can be controlled to some extent by the HPR process.

The hydroprocessing products may then optionally be subjected to exhaustive catalytic hydrogenation. This hydrogenation step may provide naphthenic kerosene containing a mixture of alkylated decalines, alkylated bicyclohexyls, alkylated hydrindanes, and cyclohexanospolyalkylated. In an optional separate processing approach, C6 -C9 alkyl phenols fractionated from the SPHDO product may be used as feedstock for the methanol etherification process leading to alkoxy phenols.

The integrated ILTF process can lead to the production of at least three valuable fuel products, provides the opportunity to perform the overall delignin conversion process in a feasible manner, and can improve the overall process economics as well as the overall economics of engineered biorefineries.

It should be understood that the above arrangements are illustrative of application to the principles of the present invention. Numerous alternative modifications and arrangements can be envisioned without departing from the spirit and scope of the invention while the present invention has been shown in the drawings and described above with respect to exemplary embodiments of the invention. It will be apparent to those of ordinary skill in the art that numerous modifications may be made without departing from the principles and concepts of the invention as set forth in the claims.

Claims (20)

A process for converting a lignin material into biofuels, characterized in that it comprises: a) subjecting the lignin material to a base catalyzed de-polymerization reaction to produce a partially depolymerized liginine; partial hydrodeoxygenation / stabilization reaction to form a partially hydrodeoxygenated product; and c) reacting the partially hydrodeoxygenated product in a refining step to form a biofuel. Process according to Claim 1, characterized in that the base catalyzed depolymerization reaction includes dissolving the lignin material in an aqueous-based catalyst in the presence of a polar solvent, subjecting dissolved lignin material to sufficient reaction conditions to depolymerize. partially lignin material, and recover partially de-limerized lignin. Process according to Claim 2, characterized in that the base catalyst is an element selected from the group consisting of NaOH, KOH, Ca (OH) 2, Mg (OH) 2 and mixtures thereof. Process according to Claim 2, characterized in that the polar solvent is water. Process according to Claim 1, characterized in that the base catalyzed depolymerisation reaction takes place from approximately 230 ° C to approximately 350 ° C. Process according to Claim 1, characterized in that the partial hydrodeoxygenation / stabilization reaction takes place from approximately 200 ° C to 300 ° C. Process according to Claim 1, characterized in that the partial hydrodeoxygenation / stabilization reaction takes place at a pressure of 35.15kgf / cm2 to approximately 140.62kgf / cm2. Process according to Claim 1, characterized in that the partial hydrodeoxygenation / stabilization reaction includes exposing the partially depolymerized lignin to a solid catalyst at a temperature below approximately 300 ° C. Process according to Claim 8, characterized in that the solid catalyst includes non-acidic support material and a catalyst material. Process according to Claim 9, characterized in that the non-acidic support material is selected from the group consisting of an activated carbon, silicon dioxide, aluminum oxide, or combinations of the same. same. Process according to Claim 8, characterized in that the catalyst material is selected from the group consisting of Co-Mo, Rh-Mo, Ru-Mo, Pt-Mo, Pd-Mo and combinations of the same. same. Process according to claim 8, characterized in that the catalyst is either supported or unsupported transition metal nitrides or transition demetal carbides. Process according to claim 12, characterized in that the supported or unsupported transition metal nitride is selected from the group consisting of VN, Mo2N, TiN, and combinations thereof. Process according to claim 12, characterized in that the supported or unsupported transition metal carbide is selected from the group consisting of WC, MoC, VC and combinations thereof. A process according to claim 8, characterized in that the partial hydrodeoxygenation / stabilization reaction takes place under conditions sufficient to convert more than approximately 95% of methoxy phenolysis benzene diols into phenol-based products having a single fraction of oxygen. A process according to claim 1, characterized in that the refining step includes a reaction selected from the group consisting of a dehydrogenation reaction, a mild hydrocracking reaction, an etherification reaction, a hydrogenation reaction and a combination thereof. Process according to Claim 1, characterized in that the refining step is a hydroprocessing reaction including a hydrodesoxygenation step and a subsequent hydrocracking step. Process according to claim 17, characterized in that the hydroprocessing reaction takes place at a temperature of from about 3200 ° C to about 450 ° C. Process according to Claim 16, characterized in that the refining step is a mild hydrocracking reaction, followed by an etherification reaction. Process according to claim 16, characterized in that it further comprises fractionating the partially dehydrated oxygen product into a first monomeric fraction and a second oligomeric fraction.