WO2018015610A1

WO2018015610A1 - Simple process for converting lignocellulosic materials

Info

Publication number: WO2018015610A1
Application number: PCT/FI2016/050530
Authority: WO
Inventors: Marcelo DOMINE; Marvin CHÁVEZ-SIFONTES; Andrea Gutierrez; Kati VILONEN; Timo STRENGELL; Pekka Jokela; Isto Eilos
Original assignee: UPM Kymmene Oy
Current assignee: UPM Kymmene Oy
Priority date: 2016-07-19
Filing date: 2016-07-19
Publication date: 2018-01-25
Anticipated expiration: 2019-01-19

Abstract

The present invention relates to a process for converting feedstock comprising lignocellulosic material, said process comprising the steps of hydrotreating the feedstock catalytically with hydrogen in the presence of an alkali and a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia, whereby an effluent is obtained, and separating the effluent, where an aqueous phase, light gaseous phase and a liquid organic phase are obtained.

Description

SIMPLE PROCESS FOR CONVERTING LIGNOCELLULOSIC MATERIALS

TECHNICAL FIELD

The invention relates to converting of lignocellulosic materials and more particularly to a simple process for converting lignocellulosic materials to aromatic compounds, hydrocarbons and other chemicals.

BACKGROUND

Lignin is one of the most abundant biopolymers in the nature and it is produced in large amounts in the paper industry. Global commercial yearly production of lignin is around 1.1 million metric tons and lignin is used in a wide range of low volume niche applications where typically the form but not the quality of lignin is important. Lignin functions as a support through strengthening of wood (xylem cells). Lignin is an unusual biopolymer because of its heterogeneity and lack of defined primary structure. The building blocks of lignin are aromatic compounds and thus it is a valuable renewable source of aromatic compounds, useful for chemical and fuel production. The chemical structures of lignin and lignin precursors (coumaryl alcohol, coniferyl alcohol and sinapyl alcohol) are shown below.

In the conversion of lignin it may be subjected to depolymerization carried out in homogeneous or heterogeneous phases where the depolymerization may be performed in the presence of catalysts. After the depolymerization the obtained depolymerized product may be hydrotreated, followed by separation of the product obtained from hydrotreating into different fractions which may further be processed into hydrocarbons or other chemicals. Conversion of lignin may also be realized by hydrotreating without depolymerization. It is necessary to depolymerize lignin to smaller oligomers and monomers, which are suitable for further processing by hydrotreating etc.

Despite the ongoing research and development of processes for the conversion of lignocellulosic materials, there is still a need to provide an improved and simple process for the conversion of lignocellulosic materials.

SUMMARY OF THE INVENTION

Disclosed herein is a process for converting feedstock comprising lignocellulosic material, wherein the process comprises the steps of hydrotreating the feedstock catalytically with hydrogen in the presence of an alkali and a catalyst composition comprising ruthenium (Ru) supported on zirconia (ZrC ), where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia, whereby an effluent is obtained, and separating from the effluent at least one of the following : an aqueous phase, light gaseous phase, liquid organic phase and residual lignin phase.

Disclosed herein are also aromatic compounds and linear and branched hydrocarbons and chemicals obtainable by the process.

Disclosed herein is also the use of said aromatic compounds and linear and branched hydrocarbons and chemicals obtainable by the process, as transportation fuels, components in transportation fuels and as industrial chemicals.

Characteristic features of said process, use of said process and products obtained by said process are presented in the appended claims.

DEFINITIONS

The term "catalytic conversion of lignocellulosic material" refers here to treating lignocellulosic material in the presence of at least one catalytic material to effect change in the structure of the lignocellulosic material, at least to reduce the molecular size and change the functionality. The term "Mgnocellulosic material" refers here to lignin or derivatives thereof and combinations thereof. The lignin or derivatives thereof may be derived from any wood or plant based material, such as wood based raw material, woody biomass, lignin containing biomass such as agricultural residues, bagasse and corn stover, woody perennials, vascular plants, recycled brown board, deinking pulp and their combinations. The term also refers to lignin or derivatives thereof obtained from Kraft black liquor (Kraft lignin), alkaline pulping process, soda process, organosolv pulping and any combination thereof, such as lignosulfonates. The weight average molecular weight of lignin isolated from the above is Mw = 500-10 000 Da, and the number average molecular weight Mn= 700-2000 Da and polydispersity is 2-4.5. The degree of polymerization of this kind of lignin is 10- 25. Lignin separated from pure biomass is sulphur-free and thus valuable in further processing.

The term "lignin" refers here to a class of complex organic polymers that form important structural materials in the support tissues of vascular plants and some algae. Chemically, lignin is a very irregular, randomly cross-linked polymer with a weight average molecular weight of 500 Daltons or higher. Said polymer is the result of an enzyme-mediated dehydrogenative polymerization of three phenyl propanoid monomer precursors, i.e. coniferyl, synapyl and coumaryl alcohols. Coniferyl alcohol is the dominant monomer in conifers (softwoods). Deciduous (hardwood) species contain up to 40% syringyl alcohol units while grasses and agricultural crops may also contain coumaryl alcohol units.

The term "zirconia" refers to zirconium oxide with the chemical formula Zr02. The crystal structure of Zr02 exists in three polymorphic phases i.e. Zr02 has three different polymorphic forms: monoclinic, tetragonal and cubic. The cubic phase is formed at very high temperatures (>2370°C), at intermediates temperatures (1150-2370°C) the oxide has a tetragonal structure, and from room temperature to 1150°C the material is stable as monoclinic structure. Each of these polymorphic phases differ structurally significantly from each other and they exhibit different acid/base properties and surface hydroxyl group concentrations.

A phase diagram for Zr02 is shown in Figure 1. (www. materia Idesiqn.com/svstem/f iles/..JZr02 phase transitrion.pdf). As can be realized from the Figure, the structures cubic, tetragonal or monoclinic are different. The chemical bond is the same Zr-0 but how they organized in the space is different. The term "monoclinic phase of zirconia" or "monoclinic zirconia" or "monoclinic ZrCh" refers here to a specific crystal structure of zirconia having characteristic X-ray diffraction patterns, i.e. 2Θ reflections at 24.3, 28.3, 31.5 and 34.5 in the X-ray diffractogram (Joint Committee on Powder Diffraction Standards Card Numbers (JCPDS), card no. 37-1484). The X-ray diffractogram of monoclinic phase of zirconia is shown in Figure 2.

The term "tetragonal phase of zirconia" or "tetragonal zirconia" or "tetragonal ZrCh"" refers here to specific crystal structure of zirconia having characteristic X-ray diffraction patterns, i.e. 2Θ reflections at 30.4 and 35.2 in the X-ray diffractogram (JCPDS card no. 17-0923). The X-ray diffractogram of tetragonal phase zirconia is shown in Figure 2.

The term "single stage" method refers here to a method or process, which is carried out in one reaction stage and where several chemical reactions happen successively and/or in parallel. The reactions may happen in one reaction vessel (reactor) or in several reaction vessels without any removal of products and/or byproducts in between the vessels. The advantage of this configuration is that the number of procedures and intermediate purification steps are reduced. Several catalytic reactions can be combined in the same one reaction stage and even in the same reaction vessel. The term "depolymerization/ hydrotreating" or "depolymerization and hydrotreating" or "hydrotreatment" or "hydrotreating" refers to catalytic conversion of lignocellulosic materials in the presence of an alkali, where depolymerization and hydrotreating of the material is carried out in one reaction stage. The depolymerization and hydrotreatong reactions, comprising any combination/combinations of the reactions of depolymerization, hydrogenation and hydrodeoxygenation, hydroisomerization, hydrodenitrification, hydrodesulfurization, hydrocracking, and coke/carbon/char gasification, coke reforming, WGS (water-gas-shift) reactions and Bouduard reactions, take place simultaneously and/or in parallel, in any order. All weight percentages regarding the catalyst composition are calculated from the total weight of the catalyst composition.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a phase diagram of ZrCh.

Figure 2 illustrates X-ray diffraction patterns of monoclinic ZrCh and tetragonal ZrCh. Figure 3 shows an embodiment of the process where lignocellulosic material is depolymerized and hydrotreated catalytically in the presence of an alkali and the catalyst composition comprising ruthenium (Ru) supported on zirconia (ZrCh). Figure 4 shows another embodiment of the process where lignocellulosic materia l is pretreated and then depolymerized and hydrotreated catalytica lly in the presence of an alkali and the catalyst composition comprising ruthenium (Ru) supported on zirconia (Zr0₂) . Figure 5 presents results of the single stage lignin depolymerization and hydrotreating using Ru supported materials as catalysts.

Figure 6 presents GPC analysis of organic phase vs residual lignin fractions obtained from Kraft lignin in a single stage depolymerization and hydrotreating catalyzed by catalyst composition comprising ruthenium (Ru) supported on zirconia (ZrCh) monoclinic material .

Figure 7 presents GPC analysis of organic phase vs residual lignin fractions obtained from Kraft lignin in a single stage depolymerization and hydrotreating catalyzed by Ru/ZrCh tetragonal material .

DETAILED DESCRIPTION

It should be understood that although an illustrative implementation of one or more embodiments a re provided below, the disclosed compositions and methods can be implemented using any number of techniques.

The disclosure should in no way be limited to the illustrative implementation, drawings, or techniques illustrated below, including the exemplary designs describe herein, but can be modified within the scope of the appended claims along with their full scope of equivalents.

It was surprisingly found that several advantageous effects may be achieved when a catalyst composition comprising ruthenium (Ru) supported on zirconia comprising 60- 100 wt% of monoclinic phase of zirconia is used in single stage catalytic conversion of lignocellulosic materials, where depolymerization and hydrotreaing are carried out simultaneously and/or in parallel, in any order. Said catalyst composition is particula rly useful as a catalyst for conversion of lignocellulosic materials to aromatic compounds, linear and branched hydrocarbons and other chemicals. It may be used in processing of lignocellulosic materials to effect one or more of the following depolymerization, hydrogenation, hydrodeoxygenation (HDO), hydroisomerization (HI), hydrodenitrification (HDN), hydrodesulfurization (HDS), hydrocracking (HC), coke reforming, coke/carbon/char gasification, WGS (water-gas-shift) reactions and Bouduard reactions, also under mild conditions.

Disclosed herein is a process for converting feedstock comprising lignocellulosic material, wherein the process comprises the steps of hydrotreating the feedstock catalytically with hydrogen in the presence of an alkali and a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia, whereby an effluent is obtained, and separating from the effluent at least one of the following : an aqueous phase, light gaseous phase, a liquid organic phase and residual lignin phase.

The residual lignin phase refers here to a phase or fraction separated from the effluent and comprising unreacted lignin.

In an embodiment the hydrotreating is accomplished in a single stage.

In Figure 3 an embodiment is presented where feedstock comprising lignocellulosic material is depolymerized and hydrotreated catalytically with hydrogen in the presence of an alkali and a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia. Feedstock comprising lignocellulosic material 10, an aqueous solution formed of alkali 11 and a mixture 13 of water and ethanol, and hydrogen 12 are directed to hydrotreating 200 in the presence of a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia, whereby an effluent 21 is obtained. The effluent 21 is directed to separation 300, where residual lignin phase 34 is separated and recycled to feedstock comprising lignocellulosic material 10, and an aqueous phase 31, light gaseous phase 32 and a liquid organic phase 33 are obtained. Optionally the liquid organic phase 33 is directed to further processing 700, which may comprise hydrotreating, isomerization, cracking, fractionation etc. and combinations thereof, to obtain one or more product streams 71.

In Figure 4 another embodiment is presented where feedstock comprising lignocellulosic material is first pretreated and then depolymerized and hydrotreated catalytically with hydrogen in the presence of an alkali and a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia. Feedstock comprising lignocellulosic material 10, an aqueous solution formed of alkali 11 and a mixture 13 of water and ethanol are directed to pretreatment 100, whereby pretreated mixture 14 is obtained, the pretreated mixture 14 comprising pretreated feedstock, water, ethanol and alkali is directed to hydrotreating 200 in the presence of hydrogen 12 and a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia, whereby an effluent 21 is obtained. Optionally alkali may be added to the hydrotreating 200 (not shown in the Figure). The effluent 21 is directed to separation 300, where residual lignin phase 34 is separated and recycled to feedstock comprising lignocellulosic material 10, and an aqueous phase 31, light gaseous phase 32 and a liquid organic phase 33 are obtained. In an embodiment the feedstock comprises lignocellulosic material selected from lignin, derivatives thereof and mixtures thereof.

Examples of lignocellulosic materials are Kraft lignin, native lignin, lignosulfonate, lignin obtained from biorefinery processes such as enzymatic, alkaline or acid hydrolysis or steam explosion, and any combinations thereof.

Lignin may be wood based, wood biomass based, corn based, bagasse based, agricultural waste based, woody perennials based, vascular plants based, recycled brown board based, deinking pulp based or nutshell based. The weight average molecular weight of lignin used as feedstock is 500-10 000 Da, preferably 600-9000 Da and most preferably 700-8000 Da.

Suitably the lignocellulosic material, such as lignin may be supplied from a feed source such as the pulp and/or paper industry or ethanol production facility or any other source.

In an embodiment the feedstock comprises 60-100 wt% of lignocellulosic material. In another embodiment the feedstock comprises 80-100 wt% of lignocellulosic material.

In another embodiment the feedstock may comprise co-feed selected from benzene ring containing polymers, such as PVC, polystyrene, PET, polyamide and the like, oil refinery vacuum distillation column bottoms, black liquor, pyrolysis oil, and combinations thereof. The feedstock may comprise co-feed not more than 50 wt%, preferably not more than 20 wt%.

In an embodiment the alkali is selected from alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, such as Na2C03, and alkaline earth metal carbonates. Preferably NaOH, KOH, CsOH, Ca(OH)₂, Sr(OH)₂ or Ba(OH)₂ is used. In an embodiment, NaOH is used as alkali.

The alkali acts as a homogeneous depolymerization catalyst in the process.

In an embodiment the molar ratio of lignocellulosic material to the alkali in the process is from 0.2 : 1 to 20 : 1, respectively.

In an embodiment the feedstock comprising lignocellulosic material is mixed in an aqueous solution to obtain a mixture comprising the feedstock comprising lignocellulosic material and the aqueous solution comprising water and the alkali.

The aqueous solution comprises water and the alkali. In an embodiment the aqueous solution comprises 1- 10 wt%, suitably 2-5 wt% of the alkali.

In an embodiment the aqueous solution may comprise a co-solvent selected from lower (C1-C5) alkyl alcohols, lower (C1-C6) alkyl ethers and lower (C1-C6) alkyl esters. Preferably the lower (C1-C5) alkyl alcohol is selected from methanol, ethanol, 1-propanol, iso-propanol, 1-butanol and sec-butanol.

In another embodiment the aqueous solution may comprise a co-solvent selected from ethyl acetate, methyl tert-butyl ether, furan, methyl furan, dimethyl furan, tetrahydrofuran, methyl-tetrahydrofuran, dimethyl-tetrahydrofuran and furfuryl alcohol.

In an embodiment the co-solvent is ethanol.

In an embodiment, in the aqueous solution, the volumetric ratio of water to the co-solvent may be from 0.5 : 1 to 10 : 1, respectively, preferably from 1 : 1 to 5 : 1, particularly preferably from 2 : 1 to 3 : 1. In an embodiment, in the aqueous solution, the volumetric ratio of water to ethanol is from 1 : 1 to 5 : 1, preferably from 1 : 1 to 3 : 1, respectively.

In an embodiment the ratio of the lignocellulosic material to Ru is from 0.25 : 1 to 30 : 1, respectively.

In an embodiment the catalyst composition comprises ruthenium supported on zirconia, where said zirconia comprises 80-100 wt% of monoclinic phase of zirconia. In an embodiment the zirconia comprises 85-100 wt% of monoclinic phase of zirconia.

In an embodiment the zirconia comprises 90-100 wt% of monoclinic phase of zirconia.

In another embodiment the zirconia comprises 95-100 wt% of monoclinic phase of zirconia.

In another embodiment the zirconia comprises 98-100 wt% of monoclinic phase of zirconia. The remaining part of zirconia may exist as tetragonal phase or another crystal form.

In an embodiment the catalyst composition comprises 0.2 - 5 wt% of Ru. In another embodiment the catalyst composition comprises 0.3 - 3 wt% of Ru. In still another embodiment the catalyst composition comprises 0.5 - 2.5 wt% of Ru.

In an embodiment the catalyst composition comprises metallic Ru particles having small average particle size, in the range from 0.1 to 30 nm. In another embodiment the catalyst composition comprises metallic Ru particles having average particle size in the range from 0.5 to 20 nm. In still another embodiment the catalyst composition comprises metallic particles having average particle size in the range from 1 to 15 nm. The particle size determination may suitably be carried out by methods based on SEM (Scanning Electron Microscope) or HR-TEM (High Resolution Transmission Electron Microscope).

In an embodiment, in the catalyst composition, the Ru metallic particles are highly dispersed onto the support. In an embodiment the metal dispersion of Ru, measured by CO chemisorption method, is in the range from 15 to 45%, where the specific surface area (BET) of zirconia is not more than 100m²/g and the Ru loading is not more than 2 wt% in the catalyst composition. In another embodiment the catalyst composition may additionally comprise at least one dopant selected from Pd, Pt, Vn, Ni, Sn, La, Ga, Co and combinations thereof. The amount of the dopant in the catalyst composition is not more than 2 wt%. The total amount of Ru and the dopant is not more than 5 wt%.

Zr02 comprising 60-100 wt% of monoclinic phase of zirconia interacts strongly with the active phase (Ru), it inhibits sintering of supported oxides in the presence of water and high temperatures, it possesses high thermal stability and good chemical stability, and it is more inert than the classical supported oxides. Further, Zr02 comprising 60-100 wt% of monoclinic phase of zirconia possesses acidity, basicity as well as reducing and oxidizing ability.

In an embodiment the catalyst composition comprises Zr02 comprising 60-100 wt% of monoclinic phase of zirconia as the only support.

In another embodiment the catalyst composition may comprise as an additional support an oxide selected from Ce02, T1O2, MgO, ZnO, S1O2 AI2O3 and combinations thereof. Examples of suitable mixtures are ZrCh-SiCh, ZrC -AkOs, ZrCh-TiCh, ZrC -ZnO, Zr02- Ce02 and ZrC -MgO, where Zr02 refers to Zr02 comprising 60-100 wt% of monoclinic phase of zirconia.

In an embodiment the support may comprise the Zr02 comprising 60-100 wt% of monoclinic phase of zirconia and less than 50 wt% of an additional support. In another embodiment the support may comprise Zr02 comprising 60-100 wt% of monoclinic phase of zirconia and less than 40 wt% of the additional support, suitably less than 30 wt% of the additional support, and even more suitably less than 20 wt% of the additional support. In still another embodiment the support may comprise Zr02 comprising 60-100 wt% of monoclinic phase of zirconia and less than 10 wt% of the additional support, suitably less than 5 wt% of the additional support, and even more suitably less than 2 wt% of the additional support. In an embodiment the hydrotreating is carried out at the temperature from 180 to 420°C. In another embodiment the hydrotreating is carried out at the temperature from 200 to 350°C. In another embodiment the hydrotreating is carried out at the temperature from 220 to 280°C.

In an embodiment the hydrotreating is carried out under the pressure from 5 to 140 bar. In another embodiment the hydrotreating is carried out under the pressure from 5 to 110 bar. In another embodiment the hydrotreating is carried out under a pressure from 10 to 70 bar.

In an embodiment the hydrotreating is carried out under the initial pressure from 5 to 80 bar H2 in batch wise operation, where the reactor is packed at room temperature, with the reaction mixture comprising feedstock, alkali in an aqueous solution and the catalyst. Then the reactor is heated until the reaction temperature and reaction pressure are reached. Reaction time in batch wise operation may be from 20 min to 24 hours. In an embodiment the hydrotreating is carried out under the pressure from 10 to 110 bar in continuous operation.

WHSV in the hydrotreating may be 0.1- 10 h ¹. In another embodiment WHSV in the hydrotreating may be 0.5-5 h ^_1.

In an embodiment the catalytic hydrotreating is carried out in the presence of water, originating from the aqueous solution. The catalyst composition comprising Ru supported zirconia comprising monoclinic phase of zirconia tolerates water. Thus it is capable of carrying out hydrotreating reactions in an environment where water (or aqueous solution) forms a part of the material to be treated.

In an embodiment the hydrotreating is carried out in a single stage in one reaction vessel.

The hydrotreating is carried out in the presence of hydrogen. The hydrotreating comprises depolymerization reactions and any combination of the reactions of hydrogenation, hydrodeoxygenation, hydroisomerization, hydrodenitrification, hydrodesulfurization, hydrocracking, coke/carbon/char gasification and coke reforming reactions, water-gas- shift reactions and Bouduard reactions, the reactions taking place simultaneously, and/or in parallel, in any order. In an embodiment the feedstock comprising lignocellulosic material is pretreated prior to subjecting to the hydrotreating to obtain a pretreated mixture. The pretreatment softens the lignocellulosic material and effects at least partly depolymerization of lignin. In an embodiment, in the pretreatment, the mixture comprising the feedstock comprising lignocellulosic material and the aqueous solution comprising the alkali is mixed at a temperature from 30 to 110°C under a pressure from 0.5 to 1.5 bar, whereby a pretreated mixture is obtained. In an embodiment the mixing is carried out at a temperature from 50 to 80°C. Suitably the mixing is carried out for 15 min to 12 hours, preferably for 0.5 to 6 hours. In an embodiment the mixing is carried out at a temperature from 40 to 80°C. In an embodiment the mixing is carried out under a pressure from 0.5 to 1.5 bar. Preferably atmospheric pressure is used.

The pretreated mixture comprises pretreated feedstock and an aqueous solution comprising the alkali. It may also comprise unreacted feedstock.

The pretreated mixture may be directed as such to the hydrotreating.

The alkali used in the pretreatment acts as homogeneous catalyst in the hydrotreating and depolymerization, whereby it may not be necessary to add alkali to the hydrotreating. Same alkali may be used in the hydrotreating and in the pretreatment.

In an embodiment the effluent obtained from the process, comprising aromatic compounds, alcohols, ethers, esters, gases and some residual lignin may be subjected separation, whereby light gaseous components, residual lignin and an aqueous phase are separated from a liquid organic phase. The liquid organic phase may be further fractionated and/or subjected to further processing, such as hydrotreating, isomerizing, cracking etc. for obtaining components suitable as biofuels, biofuel components and other chemicals. The residual lignin may be recycled to the feedstock.

The light gaseous phase comprises light gaseous components, which are mainly gases, such as unreacted (excess) hydrogen (H2), CO and CO2, methane, ethane, ethene, propane, propene, butanes and butenes that can be used in the production of H2 after optional separation of excess hydrogen (H2). This H2 produced or separated excess H2 can be recycled to the hydrotreating step. The optional separation of excess H2 may be carried out by membrane or pressure swing absorption technique. The aqueous phase typically comprises sugars, acids, some aromatic compounds (phenols) and inorganic impurities. The aromatic compounds may be separated and used as chemicals. Low molecular weight acids in the water phase may be condensed for example via ketonization and consecutive aldol condensation reactions to produce hydrocarbon mixtures for further applications. The aqueous water phase may also be used in H2 production, particularly in steam reforming.

The liquid organic phase comprises aromatic compounds, alcohols, ethers, esters and hydrocarbons.

The liquid organic phase may be fractionated and/or subjected to further processing, such as further hydrotreating to provide chemical compounds and hydrocarbon boiling in the liquid fuel range, particularly the gasoline and diesel range. The process may be carried out in any reactor or reactor system comprising one or more reactors suitable for the purpose, such as a slurry reactor CSRT (Continuous Stirred Tank) reactor, a continuous flow fixed-bed reactor, fixed bed (trickle or gas phase), loop reactor, tubular reactor (plug-flow reactor PFR and packed-bed reactor) or ebullated bed reactor.

In the single stage hydrotreating and depolymerization in the presence of the alkali and the catalyst composition comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia, a high degree of depolymerization of the lignocellulosic materials takes place.

The catalyst composition comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia may be obtained by a method comprising the steps, where in the first step an aqueous solution of Ru precursor is mixed with Zr02 comprising 60- 100 wt% of monoclinic phase of zirconia, at a temperature from 5 to 85°C to obtain a mixture,

in the second step the pH of the mixture is adjusted to 7.5 - 10 with an alkali and mixing is continued for 30 min to 30 hours,

in the third step solid material is recovered from the mixture obtained in the second step, in the fourth step the solid material is dried at a temperature from 50 to 200°C and a catalyst composition comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia is obtained. ΖΓΟ2 comprising 60-100 w% of monoclinic phase of zirconia may be obtained using hydrothermal synthesis methods or other methods known in the art.

Incorporation of Ru onto Zr02 comprising 60-100 w% of monoclinic phase may be performed by means of the above described co-precipitation method .

The Ru precursor may be selected from salts a nd organometallic complexes of Ru . The Ru precursor may be selected from [Rus(CO)i2], Ru(NH₃)4Cl2, [((Cy)RuCl2)2], [(Cp)Ru(PPh₃)₂CI)], [((pMeCp)RuCI2)2], RuCl3-3H₂0 and Ru(N0₃)₂. In a preferable embodiment the Ru precursor is selected from [Ru3(CO)i2], Ru(NH3)4Cl2, RuCl3-3H20 and

In an embodiment RuCl3-3H20 is used as Ru precursor and 0.0065 - 0.1424 grams of this precursor are diluted in an aqueous solution (20 - 30 ml) to attain 0.2 - 5.0 wt% of Ru in the final solid . In an embodiment the aqueous solution of the Ru precursor is mixed with 1 gram of the Zr02 comprising 60-100 w% of monoclinic phase of zirconia . In a n embodiment the concentration of the Ru precursor in the aqueous solution is 0.01 -1 wt%. The mixing in the first step is carried at a temperature from 5°C to 85°C, preferably from 15°C to 70°C, and most preferably from 20°C to 50°C.

In an embodiment the Zr02 comprising 60-100 w% of monoclinic phase is pretreated at 150-300 °C, suitably in air, to eliminate humidity a nd other organic impurities from the solid .

In an embodiment, the mixture is stirred in the first step for 10 min to 10 hours.

In an embodiment in the second step the alkali is selected from alkali metal hydroxides and alkaline earth metal hydroxides, preferably KOH or NaOH is used . Preferably an aqueous solution of NaOH, having concentration ranging from 0.1M to 2.0M is used .

In an embodiment, in the second step, the mixture is stirred at the temperature from 5 to 35°C. In an embodiment the mixture is stirred for 0.5-30 hours, preferably form 1 to 24 hours. In an embodiment, in the third step, the solid material is recovered by filtration, centrifuging, spray drying or the like. The solid material is suitably washed with water until pH is in the range of 6.5 - 7.5. In an embodiment in the fourth step the solid materia l is dried (under air, atmospheric pressure) at 50-200°C. Suitably the drying temperature is 60 - 140°C.

The Ru content in the thus obtained catalyst composition may be determined by ICP (inductively coupled plasma mass spectrometry) measurements.

In an embodiment the dried final solid material (the catalyst composition) is thermally activated (reduced) at 80-350°C, suitably under H2, in situ or separately, prior to its use in catalytic processing . In another embodiment the dried solid material is thermally activated at 100-300°C, suitably at 200-300°C.

The liquid orga nic phase obtained by the process may be fractionated using methods well known in the art to one or several fractions comprising aromatics, hydrocarbons boiling in the liquid fuel range and other chemicals. The aromatics, hyd rocarbons and chemicals may be used as fuels and fuel components and as starting materials in industrial processes. The liquid organic phase may also be processed further by hydrotreating, cracking, isomerizing, etc. and combinations thereof.

Disclosed herein are also a romatic compounds and linear and branched hydrocarbons obta inable by the process. The aromatics comprise benzene, toluene, ortho- and para- xylenes, ethyl-benzene, propyl-benzene, iso-propyl-benzene, di- and tri-alkyl substituted benzenes, where alkyl substituents are selected from methyl-, ethyl-, propyl- or iso- propyl .

The linear and branched hydroca rbons comprise C4-C12 linear and branched hydrocarbons selected from C4-C12 n-alkanes; and C4-C12 mono-alkyl-substituted alkanes, where alkyl substituents are selected from methyl-, ethyl, propyl-, and iso- propyl ; and also C4-C10 di- and tri- alkyl substituted alkane, where alkyl groups a re selected from methyl-, ethyl-, propyl-, and iso-propyl; a nd additionally C4-C9 alkyl substituted cycloalkanes, where alkyl groups a re selected from methyl-, ethyl-, propyl, and iso-propyl. The process for converting lignocellulosic materials to aromatic compounds, linear and branched hydrocarbons and other chemicals has several advantageous effects. It was surprising that low temperatures and pressures can be used, whereby there is no need for equipment designed for high temperature/pressure processing. Further, less side- reactions and less cracking occur, whereby less light compounds and less char, coke and gases are formed. Thus high conversion and high organic yields, and products of high quality and with low oxygen content are achieved. The "single stage" approach is very easy to operate, efficient and cost effective. Varying lignocellulosic materials may be used as feedstock, such as lignin obtained from Kraft pulping and native lignin and mixture of these.

Particularly the catalyst composition comprising Ru supported on Zr02 comprising 60- 100 w% of monoclinic phase is very efficient in conversion of lignocellulosic materials to aromatic monomers and other hydrocarbonaceous components, particularly to effect one or more of the following : depolymerization, hydrogenation, hydrodeoxygenation, hydroisomerization, hydrodenitrification, hydrodesulfurization, hydrocracking, coke/carbon/char gasification and coke reforming reractions, WGS (water-gas-shift) reactions and Bouduard reactions, simultaneously and/or in parallel, in any order.

The catalyst composition comprising Ru supported on Zr02 is very stable and resistant at conversion reaction conditions and it is more tolerant than commercial sulfided hydrotreating catalysts under the harsh conditions. Further it is active and effective even at low temperatures and pressures.

Moreover, less residual lignin and less gases are obtained in converting lignocellulosic materials, and further, the oxygen content of the products is lower.

The metal loading of the catalyst may be low, still maintaining the desired activity, whereby the need for expensive ruthenium is reduced.

Examples

The following examples are illustrative embodiments of the present invention, as described above, and they are not meant to limit the invention in any way. The invention is illustrated also with reference to the figures. Example 1.

Single stage depolymerisation and hydrotreating of lignin to hydrocarbons

Lignin was mixed in a reactor with an aqueous solution comprising NaOH (homogeneous depolymerisation catalyst) and water-ethanol mixture, and the heterogeneous hydrotreating catalyst, Ru/C (commercial as comparative catalyst) or Ru/monoclinic Zr02 comprising 90 W% of monoclinic phase of zirconia was added. H2 was introduced in the reactor at room temperature and then the temperature was increased to 250°C. At this temperature the reaction pressure was 50 bar. The conditions were maintained for 6 h before the reactor was cooled down and the resulting effluent was analyzed. The results obtained (compositions of the hydrotreated and depolymerized effluents) are presented in the Table 1 below.

Table 1 : Compositions of the hydrotreated and depolymerized effluents

Composition of EtOH + water 1 : 3 / NaOH EtOH + water 1 : 3 / NaOH

hydrotreated and Depolymerization and Depolymerization and

depolymerized hydrotreating : 5% Ru/C hydrotreating : 2% Ru/monoclinic effluent (%) 250°C, H₂= 50 bar Zr0₂, 250°C, H₂= 50 bar

Organic phase 56.51 70.44

Gas 12.66 15.95

Residual lignin 16.89 10

Tar 13.68 3.45

Ethylacetate 1.83 1.08

Alcohols 10.24 3.2

Ethers 0.15 0,09

Esters 0 0

Hydrocarbon C7 0.23 0.05

Phenol 0.14 0.04

Guaiacol 1.72 2.53

4-methylguaiacol 0.05 0.03

4-ethylguaiacol 0.59 0.31

Trimethoxy benzene 0.46 0.27

Syringol 0.26 0.17

vanillin 0.42 0.37

Iso-eugenol 0.07 0.07

Acetovanillone 0.54 0.56

Syringaldehyde 0 0 Acetosyringone 0.05 0.04

Oligomers 83.2 91.2

Oxygen content in 24.2 28.3

organic phase (%)

Processing lignin in single stage using Ru supported on monoclinic Zr02 catalyst yielded a larger organic phase than when the commercial catalyst was used. Furthermore, with the Ru supported on monoclinic Zr02 catalyst the amounts of tar and residual lignin formed were significantly lower than with the commercial catalyst. The Ru supported on monoclinic Zr02 supported catalyst converts lignin into oligomers. These molecules can be process further, for example in hydrotreating and hydrocracking to chemicals and drop-in fuels. Example 2

Single stage depolymerization and hydrotreating of lignin, with pretreatment of lignin

The process was carried out as example 1, with additional pretreatment of lignin prior to the single stage processing. Ru/Zr02 (monoclinic) and Ru/C (commercial as comparative catalyst) were used as catalysts.

The lignin feed was first pretreated for 3 h at 70°C in an aqueous solution comprising NaOH and a mixture of ethanol and water. The pretreated mixture comprising pretreated lignin, NaOH, ethanol and water was depolymerized and hydrotreated in single stage.

Compositions of the depolymerized and hydrotreated products (effluents) are provided in table 2 below.

Table 2: Compositions of the depolymerized and hydrotreated effluents

Composition of Pretreatment: EtOH + water Pretreatment: EtOH + water 1 : 3 ; depolymerized and 1 : 3; NaOH (70°C, 3h) NaOH (70 °C, 3h)

hydrotreated Depolymerization and Depolymerization and

effluent (%) hydrotreating : 5% Ru/C hydrotreating : 2% Ru/ monoclinic

(250°C, 50 bar) Zr02, (250°C, 50 bar)

Organic 73.50 79.73

Gas 20. 81 14.91

Residual lignin 11.26 10.70

Coke/ tar 6.44 4.66 Ethylacetate 1.74 0.77

Alcohols 11.39 4.16

ethers 2.30 0.28

Hydroca rbon C7 0.21 0.04

Toluene 0.01 -

Phenol 0.05 -

Guaiacol 2.23 3.73

4-methylguaiacol 0.08 0.07

4-ethylguaiacol 0.11 0.27

trimethoxy benzene 0.46 0.16

Syringol 0.27 0.43

vanillin 0.65 0.97

iso-eugenol 0.16 0.05

acetovanillone 0.44 0.77

syringa ldehyde 0.01 0.01

acetosyringone 0.06 0.09

Oligomers 65.58 88.92

When compa ring the results presented in tables 1 and 2 it can be seem that larger organic phase yields are achieved when the pretreatment is performed . Thus, it can be concluded that the pretreatment has a beneficial effect on the conversion of lignin as it seems to brea k some of the lignin structure already at the mild conditions used .

Example 3

Single stage depolymerization and hydrotreating of lignin

Kraft lignin was pretreated in an aqueous solution comprising NaOH and a mixture of EtOH and water ( 1/3 mass ratio), at 70°C/atmospheric pressure to obtain pretreated lignin mixture comprising NaOH, ethanol and water, followed by depolymerization and hydrotreating of the pretreated mixture, where NaOH in the pretreated mixture acted as the homogeneous catalyst and Ru ( 1.9 wt%) supported on Zr02 comprising 90- 100 wt% of monoclinic phase of zirconia was used as a hydrotreating /depolymerization catalyst. This hydrotreating took place under H2 atmosphere (initial pressure ~ 22 bar) and at 250°C. The procedure was repeated, with Ru/Zr02 (tetragonal) and 5 wt% Ru/C (commercial) catalysts in the depolymerization/ hydrotreating . Results are summarized in Table 3, respectively, showing the catalytic activity of Ru supported catalysts in the single stage lignin depolymerization a nd hydrotreating . Additionally, the results obtained by means of GPC analysis of the final product (organic fraction) and residual lignin for Ru/ZrC (monoclinic), Ru/ZrC (tetragonal), and Ru/C materials are given in Figures 5 to 7. Table 3 : Catalytic activity of Ru supported catalysts in the single stage lignin depolymerization and hydrotreating

Pretreatment T (°C)/P(bar) 70/atmospheric 70/atmospheric 70/atmospheric

Catalyst NaOH NaOH NaOH

Depolymerization and 250/<50 250/<50 250/<50 h hydrotreating T(°C)/P(bar)

Homogeneous catalyst and NaOH and NaOH and NaOH and hydrotreating catalyst 5%Ru/C 1.9%Ru/Zr0₂ 1.5%Ru/Zr0₂

(commercial (monoclinic) (tetragonal) catalyst)

EtOH/water ratio in pretreatment 1/3 1/3 1/3 and in hydrotreating /

depolymerization

Yields:

Organic phase % 66.51 69.04 58.31

Gas % 5.67 5.04 6.01

Residual lignin % 19.65 24.52 31.90

Total identified products (%) 22.00 15.00 14.73

Oligomeric products (%) 78.00 85.00 85.27

Alcohols (%) 9.54 2.56 1.56

Other lights (%) 1.07 0.79 0.59

Aromatics (%) 8.31 8.57 8.31

Oxygen content of the organic 23.8 26.7 28.0 phase (%)

The yield of the organic phase, i.e. the desired phase, was highest with the Ru catalyst supported on monoclinic Zr02. Even though the amount of ruthenium, the active metal, was highest for the commercial catalyst this did not improve the yield of organic phase. Having a low metal loading makes the catalyst more attractive because less of valuable Ru is needed.

Based on the results presented above, the catalyst using tetragonal Zr02 as support is the least suitable due to the low yields of organic phase achieved and its activity towards gasification reactions (highest gas yield achieved with this catalyst).

Molecular weight distribution of organic phase and residual lignin fractions (after hydrotreating and depolymerization) were determined by liquid chromatography gel permeation (GPC) technique. Analyses were carried out on a Shimadzu Nexera XR liquid chromatograph equipped with two detectors: UV-visible (PDA) and refractive index (RI), using an Agilent Technologies PLgel 5 μιη MIXED-D (300 x 7.5 mm) packed column, and polystyrene commercial samples for molecular weight calibration. Tetrahydrofuran (THF) was used as mobile phase at a flow rate of 1.0 ml/min-1 (Total time of analysis = 15 min). Samples (3-5 mg) were dissolved in 1.0 ml of THF, and then filtered with a syringe filter (0.45 μιη PTFE). Detailed results obtained from GPC analysis of the different fractions attained after the catalytic depolymerization + hydrotreating "single stage" experiments are provided in the figures 5-7. Figure 5 shows the yields achieved for organic phase, residual lignin, gas phase and coke/char fraction obtained with Ru/Zr02 (monoclinic), Ru/Zr02 (tetragonal), and Ru/C catalysts.

Figure 6 presents GPC analysis of organic phase vs residual lignin fractions obtained from Kraft lignin depolymerization and hydrotreating in "single stage" catalyzed by Ru/Zr02 Monoclinic catalyst.

Figure 7 presents GPC analysis of organic phase vs residual lignin fractions obtained from Kraft lignin depolymerization and hydrotreating in "single stage" catalyzed by Ru/Zr02 tetragonal catalyst.

Claims

1. A process for converting feedstock comprising lignocellulosic material, wherein the process comprises the steps of

hydrotreating the feedstock catalytically with hydrogen in the presence of an alkali and a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia, whereby an effluent is obtained, and

separating from the effluent to at least one of the following : an aqueous phase, light gaseous phase, liquid organic phase and residual lignin phase.

2. The process according to claim 1, wherein the hydrotreating is accomplished in a single stage.

3. The process according to claim 1 or 2, wherein the hydrotreating comprises depolymerization reactions and any combination of the reactions of hydrogenation, hydrodeoxygenation, hydroisomerization, hydrodenitrification, hydrodesulfurization, hydrocracking, coke/carbon/char gasification and coke reforming reactions, water- gas-shift reactions and Bouduard reactions, the reactions taking place simultaneously, and/or in parallel, in any order.

4. The process according to any one of claims 1-3, wherein the feedstock comprising lignocellulosic material is mixed in an aqueous solution comprising water and the alkali to obtain a mixture comprising the feedstock comprising lignocellulosic material and an aqueous solution.

5. The process according to claim 4, wherein the aqueous solution comprises 1-10 wt%, preferably 2-5 wt% of the alkali.

6. The process according to any one of claims 1-5, wherein the alkali is selected from alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, and alkaline earth metal carbonates, preferably the alkali is NaOH, KOH, CsOH, Ca(OH) 2, Sr(OH)₂ or Ba(OH)₂.

7. The process according to any one of claims 4-6, wherein the aqueous solution comprises a co-solvent selected from C1-C5 alkyl alcohols, C1-C6 alkyl ethers and C1-C6 alkyl esters, preferably the co-solvent is selected from ethyl acetate, methyl tert-butyl ether, furan, methyl furan, dimethyl furan, tetrahydrofuran, methyl- tetrahydrofuran, dimethyl-tetrahydrofuran, furfuryl alcohol, methanol, ethanol, 1- propanol, iso-propanol, 1-butanol and sec-butanol, particularly preferably the co- solvent is ethanol.

8. The process according to any one of claims 1-7, wherein the lignocellulosic material is selected from lignin, derivatives of lignin and mixtures thereof.

9. The process according to any one of claims 1-8, wherein the hydrotreating is carried out at a temperature from 180 to 420°C, preferably from 200 to 350°C and more preferably from 220 to 280°C.

10. The process according to any one of claims 1-9, wherein the hydrotreating is carried out under a pressure from 5 to 140 bar, preferably from 5 to 110 bar.

11. The process according to any one of claims 1-10, wherein in the hydrotreating the WHSV is 0.1-10 h ¹.

12. The process according to any one of claims 1-11, wherein process comprises a pretreatment prior to the hydrotreating, wherein the feedstock is pretreated in the presence of the alkali to obtain a pretreated mixture.

13. The process according to claim 12, wherein the mixture comprising the feedstock comprising lignocellulosic material and the aqueous solution comprising the alkali is mixed at a temperature from 30 to 110°C under a pressure from 0.5 to 1.5 bar, whereby a pretreated mixture is obtained.

14. The process according to claim 13, wherein the mixture comprising the feedstock comprising lignocellulosic material and the aqueous solution comprising the alkali is mixed at a temperature from 40 to 80°C.

15. The process according to claim 13 or 14, wherein the mixture comprising the feedstock comprising lignocellulosic material and the aqueous solution comprising the alkali is mixed under atmospheric pressure.

16. The process according to any one of claims 13 - 15, wherein the pretreated mixture comprises pretreated feedstock and an aqueous solution comprising the alkali.

17. The process according to any one of claims 1 - 16, wherein the catalyst composition comprises 0.2-5 wt% of Ru, preferably 0.3-3 wt% of Ru, more preferably 0.5 - 2.5 wt% of Ru.

18. The process according to any one of claims 1 - 17, wherein dispersion of Ru in the catalyst composition is in the range from 15 to 45 %, where the specific surface area of zirconia is not more than 100 m²/g and the Ru loading is not more than 2 wt%.

19. The process according to any one of claims 1 - 18, wherein the catalyst composition comprises Ru particles having average particle size in the range from 0.1 to 30 nm, preferably 0.5 to 20 nm, and more preferably 1 to 15 nm.

20. The process according to any one of claims 1 - 19, wherein the zirconia comprises 80- 100 wt% of monoclinic phase of zirconia, preferably 85-100 wt% of monoclinic phase of zirconia .

21. The process according to any one of claims 1 - 20, wherein the zirconia comprises 90- 100 wt% of monoclinic phase of zirconia, preferably 95-100 wt% of monoclinic phase of zirconia .

22. The process according to any one of claims 1 - 21, wherein the catalyst composition comprising ruthenium supported on zirconia comprises at least one dopant selected from Pd, Pt, Vn, Ni, Sn, La, Ga, Co and combinations thereof.

23. The process according to claim 22, wherein the amount of the dopant in the catalyst composition comprising ruthenium supported on zirconia is not more than 2 wt% and the total amount of Ru and the dopant is not more than 5 wt%.

24. The process according to any one of claims 1 - 23, wherein the catalyst composition comprising ruthenium supported on zirconia comprises an oxide selected from Ce02, T1O2, MgO, ZnO, S1O2, AI2O3 and combinations thereof.

25. The process according to any one of claims 1 - 24, wherein the residual lignin phase is recycled to the feedstock.

26. The process according to any one of claims 1 - 25, wherein the liquid organic phase is fractionated to fractions comprising aromatic compounds and linear and branched hydrocarbons boiling in the liquid fuel range.

27. The process according to any one of claims 1 - 26, wherein the liquid organic phase is processed further by one or several of hydrotreating, cracking or isomerizing.