CN104903425B - Recyclable buffers for hydrothermal hydrocatalytic treatment of biomass - Google Patents

Abstract

A method for hydrothermal hydrocatalytic treatment of biomass is provided. Lignocellulosic biomass solids are provided to a hydrothermal digestion unit in the presence of a digestion solvent, at least one of ammonia or a source of ammonia, and a supported hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a suitable support. Heating the lignocellulosic biomass solids and the digestion solvent in the presence of hydrogen, the supported hydrogenolysis catalyst and at least one of ammonia or a source of ammonia to form a product solution containing a plurality of oxygenated hydrocarbons and ammonia. At least a portion of the ammonia is separated and recycled to the hydrothermal digestion unit.

Description

Recyclable buffers for hydrothermal hydrocatalytic treatment of biomass

This application claims the benefit of co-pending US Provisional Patent Application Serial No. 61/739,354, filed December 19, 2012.

technical field

The present invention relates to the hydrothermal hydrocatalytic treatment of biomass in the preparation from biomass of higher hydrocarbons suitable for transportation fuels and industrial chemicals.

Background technique

There is widespread interest in developing new technologies to provide energy from non-fossil fuel sources. Biomass is a resource that shows promise as an alternative to fossil fuels. Unlike fossil fuels, biomass is also renewable.

Biomass can be used as a renewable fuel source. One type of biomass is plant biomass. Plant biomass is the most abundant source of carbohydrates in the world due to the lignocellulosic material that makes up the cell walls in higher plants. The plant cell wall is divided into two parts, the primary cell wall and the secondary cell wall. The primary cell wall provides the structure for expanding the cell and is composed of three major polysaccharides (cellulose, pectin and hemicellulose) and a class of glycoproteins. The secondary cell wall formed after the cells stop growing also contains polysaccharides and is reinforced by polymerized lignin covalently cross-linked to hemicellulose. Hemicellulose and pectin are usually present in abundance, but cellulose is the major polysaccharide and the richest source of carbohydrates. However, producing fuels from cellulose presents difficult technical problems. Some factors in this difficulty are the physical density of lignocellulose (such as wood), which can make it difficult to penetrate the biomass structure of lignocellulose with chemicals; and the chemical complexity of lignocellulose, which This makes it difficult to break down the long-chain polymeric structure of cellulose into carbohydrates that can be used to make fuels. Another factor in this difficulty is the nitrogen and sulfur compounds contained in the biomass. Nitrogen and sulfur compounds contained in the biomass may poison the catalysts used in the subsequent treatment.

Most transportation vehicles require high power density provided by internal combustion and/or propulsion engines. These engines require clean fuel, usually in liquid form or at least in compressed gas form. Due to their high energy density and their pumpability, liquid fuels are more portable, making handling simpler.

Currently, bio-based feedstocks such as biomass provide the only renewable alternative to liquid transportation fuels. Unfortunately, progress in developing new technologies for producing liquid biofuels has been slow in developing liquid fuel products, especially ones that fit within the current infrastructure. Although large quantities of fuels such as ethanol, methanol and vegetable oils, and gaseous fuels such as hydrogen and methane can be produced from biomass resources, these fuels require new distribution and/or combustion technologies adapted to their characteristics. Some of these fuels also tend to be expensive to produce and have problems with their net carbon savings. There is a need to process biomass directly into liquid fuels.

Biomass handling as feedstock is challenging due to the need for a direct combination of biomass hydrolysis to release sugars and catalytic hydrogenation/hydrogenolysis/hydrodeoxygenation of sugars to prevent breakdown into heavy fractions (caramel or tar) . In addition, nitrogen and sulfur compounds from biomass feedstocks can poison hydrogenation/hydrogenolysis/hydrodeoxygenation catalysts (such as Pt/Re catalysts) and reduce the activity of the catalysts.

Contents of the invention

It was found to be advantageous to carry out the catalytic hydrogenation/hydrogenolysis/hydrodeoxygenation of biomass using a catalyst system that tolerates nitrogen and sulfur during the reaction and yet remains active with minimal loss of active metals.

In one embodiment, a method comprises: providing lignocellulosic biomass solids to a hydrothermal digestion unit in the presence of at least one of a digestion solvent, ammonia or a source of ammonia, and a supported hydrogenolysis catalyst, the The supported hydrogenolysis catalyst contains (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixtures thereof incorporated into a suitable support; in the presence of hydrogen, the supported hydrogenolysis catalyst and ammonia or a source of ammonia heating the lignocellulosic biomass solids and the digestion solvent in the presence of at least one of, thereby forming a product solution comprising the plurality of oxygenated hydrocarbons and ammonia; and recycling at least a portion of the ammonia to the hydrothermal digestion unit.

In one embodiment, the method comprises: (i) providing lignocellulosic biomass; (ii) contacting the biomass with a digestion solvent to form pretreated biomass containing soluble carbohydrates; (iii) at contacting the pretreated biomass with hydrogen in a reaction mixture in the presence of ammonia or at least one of a source of ammonia and a supported hydrogenolysis catalyst at a temperature ranging from 150°C to less than 300°C to form Product solutions of various oxygenated hydrocarbons and ammonia, said supported hydrogenolysis catalyst comprising (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixtures thereof incorporated into a suitable support; and (iv) recycling at least a portion of the ammonia to the reaction mixture or pretreated biomass.

In another embodiment, a composition comprises:

(i) lignocellulosic biomass;

(ii) a hydrogenolysis catalyst comprising (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixtures thereof incorporated into a suitable support;

(iii) water; and

(iv) At least one of ammonia or a source of ammonia.

The features and advantages of the invention will be apparent to those skilled in the art. Numerous modifications can be made by those skilled in the art, which fall within the spirit of the invention.

Description of drawings

The drawings illustrate certain aspects of some embodiments of the invention and are not intended to limit or define the invention.

Figure 1 is a block flow diagram of a schematic illustration of one embodiment of a process 100 of the present invention.

FIG. 2 is a block flow diagram of a schematic illustration of another embodiment of a process 200 of the present invention.

detailed description

The present invention relates to the hydrothermal hydrocatalytic treatment of biomass using a catalyst system that tolerates nitrogen and sulfur during the reaction and also remains active for a long time in the presence of ammonia or a source of ammonia as a pH buffer, And the loss of active metals (such as cobalt or other non-noble metals) in the catalyst is minimal. Ammonia or a source of ammonia can be recycled as ammonia to form an ammonium salt buffer in the hydrothermal hydrocatalytic processing reaction mixture. Ammonia or a source of ammonia has been found to be an effective buffer for hydrothermal hydrocatalytic treatment of biomass that can be recycled as ammonia.

Oxygenated hydrocarbons produced by the process can be used to produce higher hydrocarbons from biomass suitable for transportation fuels and industrial chemicals. The higher hydrocarbons produced are used to form transportation fuels, such as synthetic gasoline, diesel, and jet fuel, as well as industrial chemicals. As used herein, the term "higher hydrocarbon" means a hydrocarbon having an oxygen/carbon ratio that is less than that of at least one component of the biomass feedstock. As used herein, the term "hydrocarbon" means an organic compound comprising primarily hydrogen and carbon atoms, which is also an unsubstituted hydrocarbon. In certain embodiments, the hydrocarbons of the present invention also contain heteroatoms (ie, oxygen, sulfur, phosphorus, or nitrogen), and thus the term "hydrocarbon" may also encompass substituted hydrocarbons. The term "soluble carbohydrates" refers to oligosaccharides and monosaccharides (such as pentoses and hexoses) that are soluble in the digestion solvent and can be used as starting materials for hydrogenolysis reactions.

Biomass handling as feedstock is challenging due to the need for a direct combination of biomass hydrolysis to release sugars and catalytic hydrogenation/hydrogenolysis/hydrodeoxygenation of sugars to prevent breakdown into heavy fractions (caramel or tar) . Nitrogen and sulfur compounds from biomass feed can poison hydrogenation/hydrogenolysis/hydrodeoxygenation catalysts (such as Pt/Re catalysts) and reduce the activity of the catalysts. Reduced or partially reduced nitrogen or sulfur compounds, such as those found in proteins and amino acids present in biomass feedstocks, are possible poisons for transition metal catalysts used to activate molecular hydrogen for reduction reactions. Oxidized forms of nitrogen or sulfur in the form of nitrate or sulfate can not poison many catalysts used in hydrogen activation and reduction reactions. Biomass hydrolysis starts at 120°C and continues through 200°C. Sulfur and nitrogen compounds can be removed by ion exchange resins (acidic) stable to 120°C such as those described in US publication no.US2012/0152836, but basic resins required for complete N,S removal cannot Use above (weak base) or above 60°C (for strong base resin). Temperature cycling from ion exchange at 60°C to reaction temperatures between 120-275°C exhibits a significant energy yield loss. The use of poisoning tolerant catalysts in the process to be able to directly combine biomass hydrolysis and catalytic hydrogenation/hydrogenolysis/hydrodeoxygenation of the resulting sugars would be advantageous for biomass feed processes. The methods and systems of the present invention have the advantage of using poisoning resistant catalysts for direct combined biomass hydrolysis and catalytic hydrogenation/hydrogenolysis/hydrodeoxygenation of the resulting sugars and other derived intermediates with minimal loss of active metals over time.

In some embodiments, at least a portion of the oxygenated hydrocarbons produced in the hydrogenolysis reaction are recycled within the process and system to at least partially form the in situ generated solvent used in the biomass digestion process. This recycling saves costs in providing solvents that can be used to extract nitrogen compounds, sulfur compounds and optionally phosphorus compounds from the biomass feedstock. In addition, the hydrogenation reaction can be performed together with the hydrogenolysis reaction at a temperature of 150°C to 300°C by controlling the degradation of carbohydrates during hydrogenolysis. Thus, a separate hydrogenation reaction section can optionally be avoided and the fuel formation potential of the biomass feedstock fed to the process can be increased. The process and reaction scheme described herein also results in capital cost savings and process operating cost savings. Advantages of specific embodiments are described in more detail below.

In one embodiment, a method comprises: providing lignocellulosic biomass solids to a hydrothermal digestion unit in the presence of at least one of a digestion solvent, ammonia or a source of ammonia, and a supported hydrogenolysis catalyst, the The supported hydrogenolysis catalyst contains (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixtures thereof incorporated into a suitable support; in the presence of hydrogen, the supported hydrogenolysis catalyst and ammonia or a source of ammonia heating the lignocellulosic biomass solids and the digestion solvent in the presence of at least one of, thereby forming a product solution comprising the plurality of oxygenated hydrocarbons and ammonia; and separating and recycling at least a portion of the ammonia to the hydrothermal digestion unit.

In some embodiments, the present invention provides methods comprising: providing a biomass feedstock; contacting the biomass feedstock with a digestion solvent in a digestion system to form an intermediate stream comprising soluble carbohydrates; contacting the intermediate stream with hydrogen in the presence of a catalyst and at least one of ammonia or a source of ammonia to form a plurality of oxygenated hydrocarbons (or oxygenated intermediates) and ammonia, the supported hydrogenolysis catalyst comprising (a ) sulfur and (b) Mo or W and (c) Co and/or Ni, wherein a first portion of the oxygenated hydrocarbons is recycled to form a solvent, and ammonia is recycled to the reaction mixture or digestion system; and the A second portion of the oxygenated hydrocarbons is contacted with a catalyst to form a liquid fuel.

In another embodiment, a method comprises: (i) providing biomass comprising cellulose, hemicellulose, lignin, nitrogen compounds, and sulfur compounds; (ii) contacting the biomass with a digestion solvent to forming pretreated biomass comprising carbohydrates; (iii) combining said pretreated biomass with hydrogen in a reaction mixture in the presence of ammonia or at least one of a source of ammonia and a supported hydrogenolysis catalyst In direct contact to form various oxygenated hydrocarbons, the supported hydrogenolysis catalyst contains (a) sulfur and (b) Mo or W and (c) Co and/or Ni incorporated into a suitable support.

Ammonia or a source of ammonia can be continuously or semi-continuously or periodically or initially added to or generated in the reaction system (or reaction mixture) to minimize active metal leaching and maintain catalyst activity. Suitable sources of ammonia may be, for example, ammonium carbonate, ammonium propionate, ammonium glycolate, ammonium levulinate, ammonium acetate, ammonium formate, ammonium butyrate, ammonium chloride and ammonium sulfate. It is desirable to introduce ammonia or a source of ammonia into the reaction mixture (or via pretreated biomass) in an amount sufficient to maintain the pH of the reaction mixture at the desired pH. In some reaction conditions, the desired pH may be in the range of 3-10, preferably 4-8, more preferably 5-7. In other embodiments, it may be desirable to run the reaction system under more basic conditions. The amount of ammonia or ammonia source can be adjusted accordingly.

The source of ammonia can be an ammonium salt of a weak acid such as ammonium acetate or a strong acid such as ammonium sulfate. Ammonia can be produced by adding a strong base such as KOH or NaOH to an ammonium salt of a strong acid. Such ammonia derivatives (ammonia sources) are bases derivatizable from ammonia.

Ammonia (or a source of ammonia) in water as solvent neutralizes the acetic acid under pressure.

NH ₃ +HOAc → NH ₄ ⁺ +OAc ^- in water as solvent

The reaction is reversed when heated or when the pressure is lowered. NH ₃ gas is the most volatile component, so it drives the equilibrium back to the left, providing NH ₃ gas as recirculated base.

In some embodiments, the lignocellulosic biomass that is added to the hydrothermal digestion unit continuously or semi-continuously may be added to the hydrothermal digestion unit prior to addition to the hydrothermal digestion unit, particularly when the hydrothermal digestion unit is pressurized. (solid) to pressurize. Pressurizing the cellulosic biomass solids from atmospheric pressure to a pressurized state prior to adding the cellulosic biomass solids to the hydrothermal digestion unit may be performed in one or more pressurization zones. Suitable pressurization zones that may be used to pressurize lignocellulosic biomass and introduce it into a pressurized hydrothermal digestion unit are described in more detail in commonly owned US Patent Application Publications 20130152457 and 20130152458. Suitable pressurized zones as described herein may include, for example, pressure vessels, pressurized screw feeders, and the like. In some embodiments, multiple pressurization zones can be connected in series to increase the pressure of the cellulosic biomass solids in a stepwise fashion.

Referring to Figure 1, in one embodiment of the process 100 of the present invention, biomass 2 is provided to a digestion unit 6, which may have one or more units, containing a supported hydrogenolysis catalyst, a digestion solvent 10( may be recycled from the process), and at least one of ammonia or an ammonia precursor thereby producing oxygenated hydrocarbons when heated with molecular hydrogen 21, the supported hydrogenolysis catalyst containing (a) sulfur and (b) Mo or W and (c) Co and/or Ni or mixtures thereof. The effluent product stream from digestion unit 28 contains oxygenated hydrocarbons, and at least one of ammonia or an ammonia precursor. Ammonia recycled to digestion unit 6 may be separated from product stream 30 by separation, which may be facilitated by heating or reducing pressure in separation unit 36 (eg, as overhead stream 25 ). In one embodiment, the digester-reactor may be configured as disclosed in co-pending US application no. 61/720757, filed October 31, 2012, which is incorporated herein by reference.

Referring to FIG. 2 , in one embodiment of a process 200 of the present invention, biomass 102 is provided to a digestion zone 106 , which may have one or more digesters, thereby contacting the biomass with a digestion solvent 110 . The treated biomass slurry 120 contains soluble carbohydrates and other intermediates containing sulfur and nitrogen compounds from the biomass. The sulfur and nitrogen content may vary depending on the biomass source 102 . At least a portion of the treated biomass 120 is in hydrothermal hydrocatalytic treatment zone 126 in the presence of a supported hydrogenolysis catalyst and at least one of an ammonia source or ammonia supplied through a stream containing an ammonium hydroxide precursor. Hydrogen 121 catalyzes the reaction to produce a product stream 128 containing various oxygenated hydrocarbons and ammonia and/or a source of ammonia, the supported hydrogenolysis catalyst containing (a) sulfur and (b) Mo or W and (c) Co and / or Ni; separation of ammonia from product stream (which may be ammonia containing overhead 125 ) and product stream 130 . At least a portion of the ammonia-containing stream is recycled to the reaction mixture in 126 (as in FIG. 2 ), or to the pretreated biomass via stream 120 (not shown). At least a portion of the oxidation intermediates can be further processed to produce higher hydrocarbons to form liquid fuels. The digestion zone 106 and the hydrothermal hydrocatalytic treatment zone 126 can be performed in the same reactor or in separate reactors. Treated biomass 120 may optionally be washed prior to contacting in hydrogenolysis zone (or hydrothermal hydrocatalytic treatment zone) 126 . If washing, water is most commonly used as the washing solvent.

In another embodiment (not shown), ammonium hydroxide or ammonium hydroxide precursor can be introduced together with the digestion solvent, biomass, catalyst or separately as long as the ammonium hydroxide or ammonium hydroxide precursor and the supported hydrogen The catalyst is present together in the hydrogenolysis zone.

Any suitable (eg, inexpensive and/or readily available) type of lignocellulosic biomass can be used. Suitable lignocellulosic biomass may for example be selected from, but not limited to, forestry residues, agricultural residues, herbaceous material, municipal solid waste, waste and recycled paper, pulp and paper mill residues, and combinations thereof. Thus, in some embodiments, biomass may include, for example, corn stover, rice straw, bagasse, miscanthus, sorghum bagasse, switchgrass, bamboo, water hyacinth, hardwood, hardwood chips, hardwood pulp, cork, softwood chips, softwood pulp, and/or or a combination of these ingredients. Biomass can be selected based on considerations such as, but not limited to, cellulose and/or hemicellulose content, lignin content, growing time/season, growing location/transportation cost, growing cost, harvesting cost, etc.

Prior to treatment with a digestion solvent, untreated biomass may be washed and/or reduced in size (e.g., chopped, crushed, or peeled) to aid in mobilizing the biomass or mixed and impregnated with chemicals from the digestion solvent The convenient size and certain quality. Thus, in some embodiments, providing biomass can include harvesting lignocellulose-containing plants, such as hardwood trees or softwood trees. The tree can be subjected to stripping, shredding into chips of desired thickness, and washing to remove any residual soil, dirt, etc.

It is recognized that it is desirable to wash with water prior to treatment with a digestion solvent to rinse and remove simple salts such as nitrates, sulfates and phosphates which would otherwise be present and lead to the destruction of nitrogen, sulfur and phosphorus compounds present. Measure the concentration. This washing is done at a temperature of less than 60 degrees Celsius, and wherein hydrolysis reactions, including digestion, do not occur to a significant extent. Other nitrogen, sulfur and phosphorus compounds are bound to the biomass and are more difficult to remove and require digestion and reaction of the biomass to achieve removal. These compounds can be derived from proteins, amino acids, phospholipids, and other structures within biomass, and can be potent catalyst poisons. The poisoning resistant catalysts described herein allow some of these to be more difficult to remove nitrogen and sulfur compounds present in subsequent processing.

In the digestion zone, the size-reduced biomass is contacted with a digestion solvent in which the digestion reaction takes place. The digestion solvent must effectively digest lignin.

In one aspect of said embodiment, the digestion solvent may be a Kraft-type digestion solvent comprising: (i) at least 0.5 wt%, preferably at least 4 wt% up to 20 wt%, more preferably up to 10 wt%, based on the digestion solvent, selected from At least one base of sodium hydroxide, sodium carbonate, sodium sulfide, potassium hydroxide, potassium carbonate, ammonium hydroxide and mixtures thereof, (ii) optionally 0 to 3% anthraquinone, sodium borate and and/or polysulfides; and (iii) water (as the remainder of the digestion solvent). In some embodiments, the digestion solvent may have between 0.5% and 25%, more preferably between 10 and 20%, active base. The term "active base" (AA) as used herein is the percentage of combined base compounds expressed as sodium oxide by weight of low water content biomass (dry solid biomass). Digestion is usually carried out at a cooking liquor/biomass ratio ranging from 2 to 6, preferably 3 to 5. The digestion reaction is carried out at a temperature ranging from 60°C, preferably from 100°C to 270°C, and a residence time of 0.25h to 24h. The reaction is carried out under conditions effective to provide a stream of pretreated biomass and a stream of chemical liquid, said pretreated biomass stream comprising pretreated biomass having A lignin content of less than 20% of the amount in the untreated biomass feed, the chemical liquid stream contains alkali compounds and dissolved lignin and hemicellulosic material.

Digestion may be performed in a suitable vessel such as a carbon steel or stainless steel or similar alloy pressure vessel. The digestion zone can be performed in the same vessel or in separate vessels. Cooking can be done in continuous or batch mode. Suitable pressure vessels include but are not limited to "PANDIA ^TM Digester" (Voest-Alpine Industrienlagenbau GmbH, Linz, Austria), "DEFIBRATOR Digester" (Sunds Defibrator AB Corporation, Stockholm, Sweden), M&D (Messing & Durkee) digester (Bauer Brothers Company, Springfield, Ohio, USA) and KAMYR Digester (Andritz Inc., Glens Falls, New York, USA). Depending on the concentration of active base AA, the digestion solvent has a pH of 10 to 14, preferably about 12 to 13. The contents may be maintained for a period of time at a temperature in the range of 100°C to 230°C, more preferably in the range of 130°C to 180°C. The time may range from 0.25 to 24.0 hours, preferably from 0.5 to 2 hours, after which the pretreated contents of the digester are discharged. For adequate penetration, a sufficient amount of liquid is required to ensure that all biomass surfaces are wetted. Sufficient liquid is supplied to provide the specified digestion solvent/biomass ratio. The effect of greater dilution is to reduce the concentration of active chemical species and thus the rate of reaction.

In systems using digestion solvents similar to those used in Kraft pulp and paper making processes, such as Kraft-type digestion solvents, the chemical liquid can be regenerated in a similar manner to the Kraft pulp and paper chemical regeneration process.

In another embodiment, at least partially water-miscible organic solvents having partial water solubility, preferably greater than 2% by weight in water, can be used as digestion solvents to aid in the digestion of lignin, nitrogen compounds and sulfur compounds. In one such embodiment, the digestion solvent is an aqueous-organic solvent mixture with an optional mineral acid promoter such as HCl or sulfuric acid. Oxygenated solvents exhibiting complete or partial water solubility are preferred digestion solvents. In such a process, the organic digestion solvent mixture may be, for example, methanol, ethanol, acetone, ethylene glycol, propylene glycol, triethylene glycol, and tetrahydrofurfuryl alcohol. In at least partially miscible organic solvent processes, organic acids such as acetic acid, oxalic acid, acetylsalicylic acid, and salicylic acid can also be used as catalysts (as acid promoters). The temperature used for digestion may be 130 to 270°C, preferably 140 to 220°C, and the contact time is 0.25 to 24 hours, preferably 1 to 4 hours. Preferably, a pressure of 2 to 100 bar, most typically 5 to 50 bar, is maintained in the system to avoid boiling or flashing off of the solvent.

Optionally, depending on the embodiment, the pretreated biomass stream may be washed prior to the hydrogenolysis zone. In the scrubbing system, the pretreated biomass stream can be scrubbed to remove one or more of non-fibrous cellulosic material and non-cellulosic material prior to hydrogenolysis. The pretreated biomass stream is optionally washed with an aqueous stream under conditions to remove at least a portion of the lignin, hemicellulosic material and salts in the pretreated biomass stream. For example, a pretreated biomass stream can be washed with water to remove dissolved substances, including degraded but non-treatable cellulose compounds, dissolved lignin, and/or for cooking or produced during cooking (or pretreatment) any residual alkaline chemicals (such as sodium compounds). The washed pretreated biomass stream can contain a higher solids content through further treatment as described below, such as mechanical dewatering.

In a preferred embodiment, the pretreated biomass stream is countercurrent washed. Washing can be performed at least partially within the digester and/or externally using a separate scrubber. In one embodiment of the process of the invention, the washing system comprises more than one washing step, e.g. a first wash, a second wash, a third wash, etc., which produce washed pretreated Biomass streams, washed pretreated biomass streams from the second wash, etc., which are operated counter-currently with water and then sent to subsequent processes as washed pretreated biomass streams . Water is recycled through the first recycle wash stream, the second recycle wash stream, and then to the third recycle wash stream. Water recovered from the chemical liquid stream by the concentration system can be recycled to the scrubbing system as wash water. It should be understood that the washing step may be performed in any number of steps to obtain the desired washed pretreated biomass stream. Additionally, washing can adjust the pH for subsequent steps to the desired pH for hydrothermal hydrocatalytic treatment. Ammonium hydroxide or ammonium hydroxide precursors may optionally be added at this step to adjust the pH to the desired pH for hydrothermal hydrocatalytic treatment.

In one embodiment of the process of the present invention, biomass 102 is provided to digestion zone 106, which may have one or more digestion zones and/or digestion vessels, whereby the biomass is contacted with a digestion solvent. Optionally, at least a portion of the digestion solvent is recycled from the hydrogenolysis reaction as a recycle stream. The hydrogenolysis recycle stream may contain a number of components, including in situ generated solvent, which may be at least partially or fully used as the digestion solvent. The term "in situ" as used herein refers to components produced throughout the process; it is not limited to a particular reactor used for preparation or use and is therefore synonymous with components produced in the process. The solvent generated in situ may contain oxidation intermediates. The digestion process to remove nitrogen and sulfur compounds can be varied within the reaction medium such that a temperature gradient exists within the reaction medium, allowing nitrogen and sulfur compounds to be extracted at a lower temperature than for extraction of cellulose. For example, the reaction sequence may include an increasing temperature gradient from the biomass feedstock 102 . Non-extractable solids can be removed from the reaction as an outlet stream. Treated biomass stream 120 is an intermediate stream that may comprise treated biomass at least in part in the form of carbohydrates. The composition of treated biomass stream 120 can vary and can contain a number of different compounds. Preferably, the carbohydrates included have 2 to 12 carbon atoms, even more preferably 2 to 6 carbon atoms. Carbohydrates may also have an oxygen/carbon ratio of 0.5:1 to 1:1.2. Oligomeric carbohydrates containing more than 12 carbon atoms may also be present. In one embodiment, in the presence of at least one of ammonia or a source of ammonia in the presence of (a) sulfur and (b) molybdenum and/or tungsten and (c) cobalt and/or nickel supported hydrogenolysis catalyst At least a portion of the digested slurry is contacted with hydrogen in the presence to produce a plurality of oxygenated hydrocarbons. In another embodiment, in the presence of at least one of ammonia or a source of ammonia in the presence of at least one of ammonia or a source of ammonia in the digestion solvent and containing (a) sulfur and (b) molybdenum and/or tungsten and (c) cobalt and/or nickel Lignocellulosic biomass is contacted with hydrogen in the presence of a hydrogenolysis catalyst to produce various oxygenated hydrocarbons. Ammonia or a source of ammonia and oxygenated hydrocarbons present in the product stream may be separated in a separation zone or unit 136 or 36 to produce an oxygenated hydrocarbon stream and ammonia (or an oxygenated intermediate stream) which may be recycled to 126 or 6 . A first portion of the oxygenated hydrocarbons (or oxygenated intermediate stream) from product stream 130 or 30 may be recycled to digestion zone 106 or hydrothermal digestion unit 6, respectively. A second portion of the oxygenated hydrocarbons (or oxygenated intermediate stream) is processed to produce higher hydrocarbons to form liquid fuels.

The use of separate processing zones for steps (ii) and (iii) allows for the optimization of conversion of oxidation intermediates to monoxides independently of Conditions for digestion and hydrogenation or hydrogenolysis of the digested biomass components are optimized. The lower reaction temperature in step (iii) can be advantageous to minimize the formation of heavy fraction by-products by initially carrying out the hydrogenation and hydrogenolysis steps at low temperature. This has been observed to produce an intermediate stream rich in diols and polyols but substantially free of unhydrogenated monosaccharides that would otherwise serve as heavy fraction precursors. Subsequent conversion of mostly dissolved intermediates can be efficiently carried out at higher temperatures where residence times are minimized to avoid undesired continuous reaction of monoxides to form alkane or alkene by-products. In this way, the overall yield of the desired monoxide can be improved by carrying out the conversion in two or more stages.

Dissolution and hydrolysis assisted by organic acids (such as carboxylic acids) formed by partial degradation of carbohydrate components become complete at a temperature of about 210°C. Some lignins can dissolve before hemicellulose, while others can tolerate higher temperatures. Organic in situ generated solvents, which may contain a portion of oxidized intermediates, including but not limited to light alcohols and polyols, can assist in the solubilization and extraction of lignin and other components.

At temperatures above 120 °C, carbohydrates can degrade through a series of complex self-condensation reactions to form caramel, which is considered a degradation product that is difficult to convert into fuel products. In general, some degradation reactions can be expected under aqueous reaction conditions when temperature is applied, provided that the oligomerization and polymerization reactions are not completely inhibited by water.

In certain embodiments, the hydrolysis reaction may be performed at a temperature between 20°C and 270°C and a pressure between 1 atm and 100 atm. Enzymes can be used for hydrolysis at low temperature and pressure. In embodiments comprising strong acid and enzymatic hydrolysis, the hydrolysis reaction may be carried out at a temperature as low as ambient temperature and a pressure between 1 bar (100 kPa) and 100 bar (10, 100 kPa). In some embodiments, the hydrolysis reaction may comprise a hydrolysis catalyst (eg, metal or acid catalyst) to assist the hydrolysis reaction. The catalyst can be any catalyst capable of affecting the hydrolysis reaction. For example, suitable catalysts may include, but are not limited to, acid catalysts, base catalysts, metal catalysts, and any combination thereof. Acid catalysts may include organic acids such as acetic acid, formic acid, levulinic acid, and any combination thereof. In one embodiment, an acid catalyst may be produced in the hydrogenolysis reaction and constitute a component of the oxidation intermediate stream.

In some embodiments, the digestion solvent may contain solvent generated in situ. The in situ generated solvent typically comprises at least one alcohol, ketone or polyol capable of dissolving some of the sulfur and nitrogen compounds of the biomass feedstock. For example, alcohols can be used to dissolve nitrogen compounds, sulfur compounds, and optionally phosphorus compounds, and to dissolve lignin from the biomass feedstock used in the process. The in situ generated solvent may also include one or more organic acids. In some embodiments, the organic acid can act as a catalyst in the removal of nitrogen and sulfur compounds by some hydrolysis of the biomass feedstock. Each in situ generated solvent component can be supplied by an external source, generated in-process, and recycled to the hydrolysis zone, or any combination thereof. For example, a portion of the oxidized intermediates produced in the hydrogenolysis reaction can be separated in a separator stage to be used as a solvent produced in situ in the hydrolysis reaction. In one embodiment, the solvent generated in situ can be separated, stored and selectively injected into the recycle stream to maintain a desired concentration in the recycle stream.

Each reactor vessel preferably includes an inlet and an outlet suitable for removing a product stream from the vessel or reactor. In some embodiments, the vessel in which at least some digestion occurs may include additional outlets to allow removal of portions of the reactant stream. In some embodiments, the vessel in which at least some digestion occurs may include additional inlets to provide additional solvent or additives.

Digestion can take place in any contactor suitable for solid-liquid contact. Digestion can be performed, for example, in single or multiple vessels, where the biomass solids are fully immersed in a liquid digestion solvent or contacted with the solvent in a spray bed or heap digestion mode. As another example, the digestion step can be performed in a continuous multi-zone contactor as described in US Patent No. 7,285,179 (Snekkenes et al., "Continuous Digester for Cellulose Pulp including Method and Recirculation System for such Digester"). Alternatively, digestion can occur in a fluidized bed or stirred contactor with suspended solids. Digestion can be performed batchwise in the same vessel used for pre-wash, post-wash and/or subsequent reaction steps.

The relative composition of the various carbohydrate components in the treated biomass stream affects the formation of undesirable by-products such as tars or heavy ends in the hydrogenolysis reaction. In particular, the presence of carbohydrates in the treated biomass stream as reducing sugars or at low concentrations containing free aldehyde groups can minimize the formation of undesired by-products. In a preferred embodiment, it is desirable to have carbohydrate or heavy fraction precursors in the form of readily degradable monomers in the treated biomass at a concentration of not more than 5% by weight, based on total liquid, by using a digestion zone in combination with a catalytic reaction zone. (which convert dissolved carbohydrates to oxidized intermediates) or rapid liquid recirculation, thereby keeping the concentration of total organic intermediates, which may include oxidized intermediates derived from carbohydrates, as high as possible entities (such as monoxides, diols and/or polyols).

For either of the configurations, solvent from the digestion step was used to remove most of the lignin. In one configuration, remaining lignin, if present, can be removed upon cooling or upon partial separation of oxides from the hydrogenolysis product stream, thereby constituting the precipitated solids stream. Optionally, a precipitated solids stream containing lignin may be formed by cooling the digested solids stream prior to the hydrogenolysis reaction. In another configuration, the lignin not removed using the digestion solvent enters step (iv), where during processing to produce a higher hydrocarbon stream, the lignin may precipitate upon evaporation or separation of the hydrogenolysis product stream.

Treated biomass stream 120 may contain C5 and C6 carbohydrates that may react in a hydrogenolysis reaction. For embodiments involving hydrogenolysis, oxygenated intermediates (eg, sugar alcohols, polysaccharide alcohols, carboxylic acids, ketones, and/or furans) can be converted to fuels in further processing reactions. The hydrogenolysis reaction contains hydrogen and a hydrogenolysis catalyst to assist the reaction. Various reactions may result in the formation of one or more oxygenated hydrocarbons (or oxygenated intermediate streams) 130 .

One suitable method for carrying out the hydrogenolysis of carbohydrate-containing biomass comprises combining a carbohydrate or stable hydroxyl intermediate with a hydrogenolysis reaction under conditions effective to form a reaction product comprising smaller molecules or polyols. Hydrogen or hydrogen in a suitable gas mixture and a hydrogenolysis catalyst. Most typically, the hydrogen is dissolved in a liquid mixture of carbohydrates that is contacted with the catalyst under conditions that provide a catalytic reaction. At least a portion of the carbohydrate feed is in direct contact with hydrogen in the presence of a hydrogenolysis catalyst. By the term "directly", the reaction is carried out on at least a portion of the carbohydrate without stepwise first converting all of the carbohydrate to a stable hydroxyl intermediate. The term "smaller molecule or polyol" as used herein includes any molecule of lower molecular weight which may include a lower number of carbon or oxygen atoms than the starting carbohydrate. In one embodiment, the reaction product comprises smaller molecules including polyols and alcohols. This aspect of hydrogenolysis requires the breaking of carbon-carbon bonds, where hydrogen is supplied to meet the bonding requirements of the resulting smaller molecules, as shown for the following examples:

RC(H) ₂ -C(H) ₂ R'+H ₂ →RCH ₃ +H ₃ CR'

where R and R' are any organic moieties.

In one embodiment, carbohydrates (e.g., 5 and/or 6 carbon carbohydrate molecules) can be converted to stable hydroxyl intermediates comprising propylene glycol, ethylene glycol, and glycerol using a hydrogenolysis reaction in the presence of a hydrogenolysis catalyst. body.

The hydrogenolysis catalyst may comprise a support material into which has been incorporated or loaded with a metal component which is a metal compound active for the catalytic hydrogenolysis of soluble carbohydrates or convertible to the catalytic hydrogenolysis of soluble carbohydrates active metal compounds. The support material may comprise any suitable inorganic oxide material commonly used to support catalytically active metal components. Examples of potentially usable inorganic oxide materials include alumina, silica, silica-alumina, magnesia, zirconia, boria, titania, and mixtures of any two or more of such inorganic oxides . Preferred inorganic oxides for forming the support material are alumina, silica, silica-alumina, and mixtures thereof. However, alumina is most preferred.

In the preparation of hydrogenolysis catalysts, the metal component of the catalyst composition may be incorporated into the support material by any suitable method or device which provides a support material loaded with an active metal precursor, whereby the composition comprises Carrier materials and metal components. One method of incorporating the metal component into the support material includes, for example, co-milling the support material with the active metal or metal precursor to produce a co-milled mixture of the two components. Alternatively, another method includes co-precipitating the support material and the metal component to form a co-precipitated mixture of the support material and the metal component. Alternatively, in a preferred method, the support material is impregnated with the metal component using any of the known impregnation methods such as incipient wetness to incorporate the metal component into the support material.

When the impregnation method is used to incorporate the metal component into the support material, it is preferred that the support material is shaped into shaped particles comprising an inorganic oxide material, before being loaded with the active metal, preferably by impregnating said shaped particles with an aqueous solution of a metal salt. body to provide a support material containing the metal of the metal salt solution. To form shaped particles, the inorganic oxide material, preferably in powder form, is mixed with water and, if desired or required, a peptizer and/or binder to form a mixture which can be shaped into agglomerates. The mixture is desirably in the form of an extrudable paste suitable for extrusion into extrudate particles which may have various shapes such as cylinders, trilobes, etc. and such as 1/16", 1/2" 8", 3/16", etc. The carrier material of the composition of the present invention is therefore preferably a shaped particle comprising an inorganic oxide material.

The calcined shaped particles may have a surface area in the range of 1 m ² /g to 500 m ² /g (determined by the BET method using N ₂ , ASTM test method D 3037).

In one embodiment, the calcined shaped particles are impregnated with the metal component in one or more impregnation steps using one or more aqueous solutions containing at least one metal salt, wherein the metal compound of the metal salt solution is an active metal or active metal precursors. The metal elements are (a) molybdenum (Mo) and (b) cobalt (Co) and/or nickel (Ni). Phosphorus (P) may also be a desired component. For Co and Ni, metal salts include metal acetates, metal formates, metal citrates, metal oxides, metal hydroxides, metal carbonates, metal nitrates, metal sulfates, and both of them. species or more. Preferred metal salts are metal nitrates, such as nickel or cobalt nitrates, or both. For Mo, metal salts include metal oxides or metal sulfides. Salts containing Mo and ammonium ions are preferred, such as ammonium heptamolybdate and ammonium dimolybdate.

Phosphorus is an additive that can be incorporated into these catalysts. Phosphorus may be added to increase the solubility of the molybdenum and allow the formation of a stable solution of cobalt and/or nickel and molybdenum for impregnation. Without wishing to be bound by theory, it is believed that phosphorus can also promote hydrogenation and hydrodenitrogenation (HDN). The ability to promote HDN is an important one since nitrogen compounds are known inhibitors of the HDS response. The addition of phosphorus to these catalysts increases HDN activity, which increases HDS activity due to the removal of nitrogen inhibitors from the reaction medium. The ability of phosphorus to also promote hydrogenation is also beneficial to HDS, as some of the difficult sterically hindered sulfur molecules are desulfurized primarily via an indirect mechanistic pathway that undergoes initial hydrogenation of the aromatic rings in these molecules. The hydrogenation activity of these catalysts promoted by phosphorus increases the desulfurization of these types of sulfur-containing molecules. The phosphorus content of the final catalyst is generally in the range of 0.1 to 5.0 wt%.

The concentration of the metal compound in the impregnation solution is chosen to provide the desired metal content in the final composition of the hydrogenolysis catalyst, taking into account the pore volume of the support material to be impregnated by the aqueous solution. Typically, the concentration of the metal compound in the impregnation solution is in the range of 0.01 to 100 mol/liter.

Cobalt, nickel or combinations thereof may be present in the support material having the metal component incorporated therein in an amount ranging from 0.5 wt% to 20 wt%, preferably from 1 wt% to 15 wt%, most preferably from 1 wt% to 12 wt%, to Based on the metal components (b) and (c) in the form of metal oxides; Among the support materials of the metal components therein, the metal components (b) and (c) are in the form of metal oxides. The above weight percentages of the metal component are based on the dry support material and the metal component as an element (change "element" to "metal oxide form"), regardless of the actual form of the metal component.

The metal loaded catalyst can be sulfided for use as a hydrogenolysis catalyst before it is loaded into a reactor vessel or system, or it can be sulfided in situ in a gas phase or liquid phase activation procedure. In one embodiment, the liquid soluble carbohydrate feedstock may be contacted with a sulfur-containing compound, which may be hydrogen sulfide or a compound that decomposes to hydrogen sulfide, under the contacting conditions of the present invention. Examples of such decomposable _compounds include mercaptans, CS2, thiophenes, dimethyl sulfide (DMS), dimethyl sulfoxide (DMSO), sodium hydrosulfide, and dimethyl disulfide (DMDS). Also, preferably, by contacting the hydrogen-treated composition with a suitable feed source containing a concentration of sulfur compounds under suitable sulfidation treatment conditions. The sulfur compound of the hydrocarbon feedstock may be an organosulfur compound, particularly an organosulfur compound derived from a biomass feedstock or other sulfur-containing amino acids such as cysteine.

Suitable sulfidation treatment conditions are those that provide conversion of the active metal components of the precursor hydrogenolysis catalyst to their sulfided forms. Typically, the sulfidation temperature of the precursor hydrogenolysis catalyst in contact with the sulfur compound is in the range of 150°C to 450°C, preferably 175°C to 425°C, most preferably 200°C to 400°C.

When using a soluble carbohydrate feedstock to be treated with a catalyst for sulfidation, the sulfidation conditions may be the same as the process conditions for hydrogenolysis. The vulcanization pressure may generally range from 1 bar to 70 bar, preferably from 1.5 bar to 55 bar, most preferably from 2 bar to 35 bar. The resulting active catalyst generally has a sulfur content incorporated therein in an amount ranging from 0.1 wt% to 40 wt%, preferably from 1 wt% to 30 wt%, most preferably from 3 wt% to 24 wt%, as the metal component (b) in the form of a metal oxide and (c) count.

The conditions under which the hydrogenolysis reaction is carried out will vary based on the type of biomass starting material and the desired product (eg, gasoline or diesel). Those skilled in the art having the benefit of this disclosure will know appropriate conditions for carrying out the reactions. Typically, the hydrogenolysis reaction may be carried out at a temperature ranging from 110°C to 300°C, preferably from 170°C to less than 300°C, most preferably from 180°C to 290°C.

It has been found that supplying a buffer to the hydrogenolysis reaction mixture during the reaction can prolong catalyst life.

In one embodiment, the hydrogenolysis reaction is in the range of 0.2 to 200 bar (20 to 20,000 kPa), preferably in the range of 20 to 140 bar (2000 kPa to 14000 kPa), even more preferably in the range of 50 to 110 bar (5000 to 11000 kPa) under internal pressure.

The hydrogen used in the hydrogenolysis reaction of the present invention may include external hydrogen, recycled hydrogen, in situ generated hydrogen, and any combination thereof.

In one embodiment, less carbon dioxide and a greater amount of polyol can be produced using a hydrogenolysis reaction than a reaction that results in reforming of the reactants. For example, reforming can be represented by the formation of isopropanol (i.e., IPA or 2-propanol) from sorbitol:

C ₆ H ₁₄ O ₆ +H ₂ O → 4H ₂ +3CO ₂ +C ₃ H ₈ O; dHR=-40J/g-mol (equation 1)

Alternatively, polyols and monoxides such as IPA can be formed by hydrogenolysis in the presence of hydrogen, where hydrogen is consumed rather than produced:

C ₆ H ₁₄ O ₆ + 3H ₂ → 2H ₂ O + 2C ₃ H ₈ O ₂ ; dHR = +81 J/gmol (equation 2)

C ₆ H ₁₄ O ₆ + 5H ₂ → 4H ₂ O + 2C ₃ H ₈ O; dHR = -339 J/gmol (equation 3)

Due to differences in reaction conditions (eg, the presence of hydrogen), the product of the hydrogenolysis reaction may contain greater than 25 mole percent, or greater than 30 mole percent polyol, which may result in greater conversion in subsequent work-up reactions. Additionally, reactions using hydrogenolysis rather than reforming conditions may result in less than 20 mole percent, or less than 30 mole percent carbon dioxide production. "Oxidation intermediate" as used herein generally refers to hydrocarbon compounds (referred to herein as C1+O1-3 hydrocarbons) having one or more carbon atoms and between 1 and 3 oxygen atoms, such as polyols and Smaller molecules (such as one or more polyols, alcohols, ketones, or any other hydrocarbon having at least one oxygen atom).

In one embodiment, the hydrogenolysis is carried out under neutral or acidic conditions as desired to accelerate the hydrolysis reaction in addition to the hydrogenolysis. Hydrolysis of oligomeric carbohydrates can be combined with hydrogenation to produce sugar alcohols which can undergo hydrogenolysis.

The second aspect of hydrogenolysis requires the breaking of -OH bonds, as in:

RC(H) ₂ -OH+H ₂ →RCH ₃ +H ₂ O

This reaction is also known as "hydrodeoxygenation" and can be carried out simultaneously with C-C bond breaking hydrogenolysis. Glycols can be converted to monoxides via this reaction. As the severity of the reaction is increased by increasing the temperature or contact time with the catalyst, the concentration of polyols and diols relative to monoxides decreases due to the reaction. The selectivity for hydrogenolysis of C-C versus C-OH bonds will vary with catalyst type and formulation. Complete deoxygenation to alkanes can also occur, but is generally undesirable if the aim is to produce monoxides or diols and polyols that can be condensed or oligomerized to higher molecular weight fuels in subsequent processing steps . In general, it is desirable to send only monoxides or diols to subsequent processing steps, as higher polyols may cause excessive coke formation on the condensation or oligomerization catalysts, while alkanes are essentially unreactive and cannot be incorporated to Produce higher molecular weight fuels.

Thus, in the reaction zone, the reaction mixture may contain:

(i) lignocellulosic biomass;

(ii) a hydrogenolysis catalyst comprising (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixtures thereof incorporated into a suitable support;

(iii) water; and

(iv) At least one of ammonia or a source of ammonia.

In some embodiments, the composition may further comprise (v) digested organic solvents. In another embodiment, the catalyst may also comprise (d) phosphorus.

In one embodiment of the present invention, in addition to an optional hydrogenation reaction such as that described in co-pending patent application publication nos. Conversion to stable hydroxyl intermediates comprising the corresponding alcohol derivatives is carried out by hydrogenolysis in a suitable reaction vessel.

Oxidation intermediate stream 130 may then be sent from the hydrogenolysis system to further processing stages. In some embodiments, the optional separation stage includes elements that allow separation of the oxygenated hydrocarbons into different components. In some embodiments of the invention, the separation stage may receive the oxygenated intermediate stream 130 from the hydrogenolysis reaction and separate the various components into two or more streams. For example, suitable separators may include, but are not limited to, phase separators, strippers, extractors, filters, or distillation columns. In some embodiments, a separator is installed prior to working up the reaction to facilitate the production of higher hydrocarbons by separating higher polyols from oxidation intermediates. In such an embodiment, higher polyols can be recycled back to the hydrogenolysis reaction, while other oxidized intermediates are sent to the work-up reaction. Additionally, when recycled to digester 106, the outlet stream from the separation stage containing a portion of the oxidized intermediates may serve as an in situ generated digestion solvent. In one embodiment, a separation stage may also be used to remove some or all of the lignin from the oxidation intermediate stream. The lignin can leave the separation stage as a separated stream, for example as an outlet stream.

In one embodiment, the processing reaction may include a condensation reaction to produce a fuel blend. In one embodiment, higher hydrocarbons may be part of a fuel blend used as a transportation fuel. In this embodiment, the condensation of the oxidation intermediate is carried out in the presence of a catalyst capable of forming higher hydrocarbons. While not intending to be bound by theory, it is believed that the production of higher hydrocarbons proceeds by stepwise addition reactions involving carbon-carbon bond formation. The resulting reaction products include any number of compounds, as described in more detail below.

Referring to FIG. 1 , in some embodiments, outlet stream 130 comprising at least a portion of the oxidation intermediates can be sent to one or more processing reactions. Suitable processing reactions may include various catalysts for condensing one or more oxygenated intermediates to higher hydrocarbons, defined as hydrocarbons containing more carbon than the oxygenated intermediate precursors. Higher hydrocarbons may constitute fuel products. The fuel product produced by the process reaction represents the product stream from the overall process at the higher hydrocarbon stream. In one embodiment, the higher hydrocarbons produced by the treatment reaction have an oxygen/carbon ratio of less than 0.5, or less than 0.4, or preferably less than 0.3.

The oxidation intermediate can be processed in one or more processing reactions to produce a fuel blend. In one embodiment, the condensation reaction may be used along with other reactions to produce the fuel blend, and the condensation reaction may be catalyzed by a catalyst comprising acidic functional sites or basic functional sites, or both. In general, without being bound by any particular theory, it is believed that basic condensation reactions generally consist of a series of steps comprising: (1) an optional dehydrogenation reaction; (2) an optional dehydration reaction which may be catalyzed by an acid; (3) an aldol condensation reaction; (4) an optional ketoylation reaction; (5) an optional furan ring-opening reaction; (6) hydrogenation of the resulting condensation product to form a C4+ hydrocarbon; and (7) any of them combination. Acid-catalyzed condensations may similarly require optional hydrogenation or dehydrogenation reactions, dehydration and oligomerization reactions. Additional polishing reactions may also be used to conform the product to specific fuel standards, including reactions performed in the presence of hydrogen and a hydrogenation catalyst to remove functional groups from the final fuel product. The condensation reaction can be carried out using a catalyst comprising basic functional sites, both acidic and basic functional sites, and optionally metallic functionality.

In one embodiment, an aldol condensation reaction may be used to produce a fuel blend that meets the requirements of diesel fuel or jet fuel. In one embodiment of the invention, the fuel yield of the current process may be greater than other bio-based feedstock conversion processes. Without wishing to be bound by theory, it is believed that the presence of ammonium hydroxide or ammonium hydroxide precursors and nitrogen or sulfur tolerant catalysts used in the process prolongs the life of such catalysts by preventing leaching of active metals such as cobalt.

In order to facilitate a better understanding of the present invention, the following examples of certain aspects of some embodiments are provided. The following examples should not be read as limiting or defining the full scope of the invention.

Example

Example 1: Ammonia Buffer

A 75 ml Parr 5000 reactor was charged with 30.21 grams of 50 wt% glycerol in deionized water, 0.202 grams of ammonium carbonate buffer, and 0.304 grams of catalyst (DC-2534 containing 1-10% cobalt oxide on alumina and molybdenum trioxide (up to 30 wt%), and less than 2% nickel), the catalyst was obtained from Criterion Catalyst & Technologies L.P. and sulfided by the method described in Example 5 of US2010/0236988.

The reactor was pressurized to 53 bar with hydrogen, and the reactor was heated to 250° C. for 5 hours. A final pH of 5.6 was obtained, indicating effective buffering of acetic acid and other acids formed as reaction by-products.

The reactor product was analyzed by gas chromatography using a 60mx0.32mm ID DB-5 column with 1 μm thickness, 50:1 split ratio, 2 mL/min helium flow, and column oven held at 40° C. for 8 minutes, Afterwards, it was raised to 285°C at 10°C/min, and the holding time was 53.5 minutes. The injector temperature was set at 250°C and the detector temperature was set at 300°C. GC analysis indicated a 26% conversion of glycerol, forming 1,2-propanediol as the main product, and a few weight percents of ethanol and propanol.

Example 2: Distillation with ammonia buffer

The reactor contents from Example 1 were short path distilled at atmospheric pressure under a nitrogen blanket. Distillation was continued at a bottoms temperature of 142.5 to 245°C to produce an overhead product of 50.1% of the initial charge. The pH of the distillate averaged 7.5, while a final distillate sample comprising 8% of the initial charge obtained a pH of 8.6. The pH of the remaining bottom fraction was 6.6.

This example illustrates the ability to distill an ammonia buffer overhead as a base that can be recycled to neutralize acidity in subsequent reaction cycles.

Examples 3 and 4: Buffer recirculation

Two 75 ml Parr 5000 reactors were loaded with 10 grams of deionized water as solvent, 0.25 grams of DC-2534 catalyst from Example 1, and 2.7 grams of southern pine flakes (39% moisture). 10 grams of the combined overheads from Example 2 (pH 8.6) were added to the reactor in Example 3. For Example 4, 10 grams of deionized water was added.

Both reactors were pressurized to 52 bar with hydrogen and heated to 190°C for 1 hour and then to 250°C for 4 hours with stirring. After digestion and reaction, both reactors were cooled and depressurized, then opened and the reactor contents filtered through Whatman GF/F filter paper to assess the percentage of digested wood solids. For both reactors, digestion was almost complete. However, the pH of Example 3 with added overhead was 3.5 at the end of the reaction, compared to a pH of 2.8 when deionized water was added instead of distillate.

GC analysis indicated twice the concentration of the target monoxide and glycol intermediates of Example 3 with added distillate compared to Example 4.

This result demonstrates that the biomass digester reactor can be buffered to achieve higher pH via recycle of overheads from Examples 1 and 2 (where ammonium carbonate was used as buffer) followed by distillation.

Claims (14)

1. A hydrothermal hydrocatalytic treatment method of biomass, comprising: (i) dissolving lignocellulosic biomass solids in the presence of at least one of a digestion solvent, ammonia or an ammonia source and a supported hydrogenolysis catalyst Provided into a hydrothermal digestion unit, the supported hydrogenolysis catalyst contains (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixtures thereof incorporated into a suitable support; (ii) Heating the lignocellulosic biomass solids and the digestion solvent in the presence of hydrogen, a supported hydrogenolysis catalyst, and at least one of ammonia or a source of ammonia, thereby forming a product solution comprising the plurality of oxygenated hydrocarbons and ammonia; and (iii ) recycle at least a portion of the ammonia to the hydrothermal digestion unit. 2. A method for the hydrothermal hydrocatalytic treatment of biomass comprising: (i) providing lignocellulosic biomass; (ii) contacting the biomass with a digestion solvent to form pre-treated biomass containing soluble carbohydrates Treated biomass; (iii) allowing said pretreated biomass in a reaction mixture at a temperature ranging from 150°C to less than 300°C in the presence of at least one of ammonia or a source of ammonia and a supported hydrogenolysis catalyst Biomass is contacted with hydrogen to form a product solution containing various oxygenated hydrocarbons and ammonia, the supported hydrogenolysis catalyst contains (a) sulfur, (b) Mo or W incorporated into a suitable support, and (c ) Co, Ni, or mixtures thereof; and (iv) recycling at least a portion of the ammonia to the reaction mixture or pretreated biomass. 3. The method of claim 1 or 2, wherein the source of ammonia is an ammonium salt. 4. The method according to claim 3, wherein the ammonium salt is selected from the group consisting of ammonium carbonate, ammonium propionate, ammonium glycolate, ammonium levulinate, ammonium acetate, ammonium formate, ammonium butyrate, ammonium chloride and ammonium sulfate . 5. The method according to claim 1 or 2, wherein ammonia is provided to the reaction mixture. 6. The method of claim 1 or 2, wherein ammonia is generated externally to the reaction mixture. 7. The method of claim 1 or 2, wherein the source of ammonia is provided by adding a strong base to an ammonium salt of a strong acid. 8. The method according to claim 7, wherein the strong base is KOH or NaOH, and the ammonium salt is ammonium sulfate. 9. The method according to claim 1 or 2, wherein a first portion of the oxygenated hydrocarbons is recycled to partially form the digestion solvent. 10. The method of claim 2, wherein a first portion of the oxygenated hydrocarbons is recycled to partially form the solvent in step (ii). 11. A method according to claim 2 or 10, wherein ammonia is recycled with the first portion of the oxygenated hydrocarbons. 12. The method according to claim 2 or 10, wherein ammonia is recycled separately to the reaction mixture or the pretreated biomass as an ammonia stream. 13. The process according to claim 1 or 2, wherein the catalyst has a sulfur content in the range of 0.1 wt% to 40 wt%, based on components (b) and (c) as metal oxides. 14. The process according to claim 1 or 2, wherein the catalyst has a Co and/or Ni content in the range of 0.5 wt% to 20 wt% as components (b) and (c) in the form of metal oxides count.