A biomass viscosity-enhancing modification and tar hydrogenation utilization process

Abstract

The present invention belongs to the technical field of biomass utilization, and specifically relates to a biomass thickening modification and a hydrogenation utilization process of its tar, which specifically comprises: selecting biomass, crushing, screening, preparing skeleton materials and carbon-forming main materials, pyrolysis, hydrogenation, desulfurization and deoxygenation, mixing the obtained solids to prepare a binder, and preparing carbon-forming through the binder. The present invention does not use hydrogen as a raw material, but utilizes a super / subcritical system to hydrolyze and transform the biomass to make it have a binder function, and participate in the subsequent preparation of biomass carbon-forming. The hydrogenation thickening of waste biomass solids and the hydrogenation deoxygenation and desulfurization process of biomass tar are realized, and the green and low-carbon circular development of biomass is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass utilization, and in particular relates to a biomass viscosity-increasing modification and a tar hydrogenation utilization process. Background Art

[0002] The annual output of straw in rural my country exceeds 700 million tons. The high storage and transportation costs and low product added value in the resource utilization process have seriously restricted its industrialization process. The waste residue of Chinese medicinal materials in my country is a high-humidity solid waste material with a moisture content of more than 80%, which is not conducive to storage or reprocessing. Biomass represented by straw and Chinese medicinal residue is itself a high-water organic matter, which requires dehydration and pyrolysis to obtain biomass oil. The biomass oil produced in the biomass pyrolysis process has a high oxygen content, and some oxygen needs to be removed to be converted into high-quality oils. However, biomass oil needs to undergo complex and harsh hydrogenation and deoxygenation treatment before it can produce second-generation alkane biofuels, and the production cost is too high.

[0003] Bio-oil contains a large number of oxygen-containing functional groups such as carbonyl and carboxyl. These oxygen-containing functional groups are the root cause of the high acidity, poor stability and low calorific value of bio-oil. Hydrodeoxygenation can effectively remove oxygen-containing groups in bio-oil, reduce the oxygen content and improve the quality of bio-oil. When preparing advanced fuels from biomass oil, the oil hydrogenation process usually includes the following two steps: the first step is to convert unsaturated fatty acids and triglycerides into saturated fatty acids through catalytic hydrogenation, and the saturated fatty acids are converted into straight-chain alkanes through hydrodeoxygenation, in which the oxygen atoms are removed in the form of H2O or carbon oxides; the second step is to hydrocracking and hydroisomerizing the straight-chain alkanes obtained in the first step under the action of a catalyst to generate isoalkanes, so as to achieve the purpose of lowering the freezing point, improving low-temperature fluidity, etc., and improving the quality of oil products.

[0004] Traditional biomass catalytic pyrolysis experiments are generally carried out in a fixed bed reactor or fluidized bed under nitrogen flow. The catalysts include HZSM-5, ZSM-5, A1-SBA-15, etc. When HZSM-5 or HZSM-5 / AL2O3 is used as a catalyst, catalytic pyrolysis can make the aromatic content in the bio-oil higher. This type of catalyst has a good deoxygenation effect and is the main method for biomass oil hydrogenation modification. The reaction temperature of catalytic hydrogenation of bio-oil based on pyrolysis tar is usually within 400°C. It is a bio-oil upgrading technology that is carried out under high pressure conditions and in the presence of hydrogen or hydrogen-donating solvents, and the bio-oil is subjected to a catalyst to undergo a hydrogenation reaction, and the original oxygen element is removed in the form of water or carbon oxides. The process is usually accompanied by chemical reactions such as hydrodesulfurization, hydrodenitrogenation, and hydrogenation saturation of unsaturated hydrocarbons.

[0005] Research has found that water is an excellent solvent for hydrocarbons near its critical point (340°C, 22.1MPa) or in a supercritical state. It has high solubility, is conducive to the dissolution of small molecular components in biomass, and provides a suitable reaction environment for biomass oil hydrogenation. Taking advantage of the high water content of biomass, using water as raw material, and in the presence of CO atmosphere, the hydrogen (active hydrogen, not hydrogen) produced by the water-CO supercritical reaction is highly active, making it easy for certain bonds of oxygen-containing functional groups in biomass oil to break through hydrogenolysis to generate small molecular compounds. At the same time, the water-CO supercritical system can consume the water produced by biomass and reduce the discharge of water.

[0006] Patent CN200710017449.9 proposes a method for treating coal tar with supercritical solvent hydrogenation, wherein a coal tar raw material is added into a reactor, and a solvent A having a volume ratio of 1:1-1:3 to the coal tar raw material and a catalyst B having an amount of 1wt%-18wt% of the coal tar raw material are added, and a lightening reaction is carried out in the presence of hydrogen; the liquid product coming out of the reactor is distilled to cut out water, solvent, heavy oil and light oil fractions. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies in the prior art and provide a process for the thickening and modification of biomass and the hydrogenation utilization of its tar, which solves the problems of insufficient biomass carbon adhesion, biomass water utilization and biomass tar deoxygenation and hydrogenation process. The present invention provides a process for the thickening and modification of biomass and the hydrogenation utilization of its tar.

[0008] The technical solution adopted by the present invention is:

[0009] A biomass viscosity modification and tar hydrogenation process comprises the following steps:

[0010] In the first step, a certain mass fraction of biomass is selected, and the biomass is crushed and sieved to obtain a solid mixture A;

[0011] In the second step, the solid mixture A obtained in the first step is divided into three parts according to a certain ratio, the first part of the solid mixture A is subjected to hydrolysis and fermentation treatment for a certain period of time, and a solid mixture B and a liquid C are obtained by filtration;

[0012] The third step is to heat the second solid mixture A prepared in the second step to 650° C. for pyrolysis, and collect the solid mixture D, tar E and pyrolysis gas F after pyrolysis.

[0013] The fourth step is to mix the liquid C prepared in the second step, the solid mixture D obtained in the third step, and the tar E prepared in the third step, and put them into a CO2-water supercritical reactor to complete the CO2-water supercritical hydrogenation reaction of the tar, and finally obtain the hydrogenated biomass solid part G and the tar H that has completed the hydrodeoxygenation and desulfurization process;

[0014] The fifth step is to mix the solid mixture B obtained in the second step with the biomass solid part G obtained in the fourth step to form a binder J;

[0015] Step 6: The third solid mixture A prepared in the second step and the binder J obtained in the fifth step are mixed evenly in a certain proportion, hot melt press molding is completed, and the residual tar H is squeezed out under a certain pressure to obtain the biomass carbon K;

[0016] In the seventh step, the biomass carbon J is heated to 650° C. at a certain heating rate, and the biomass carbon K, tar L and pyrolysis gas M after pyrolysis are collected.

[0017] Furthermore, in the first step, the biomass comprises any one of straw and Chinese medicinal residue or any combination of the two in any proportion, the moisture content of the solid mixture A exceeds 20wt%, the mass fraction is 100 parts, and the particle size of the solid mixture A after crushing and screening is 1-20mm.

[0018] Furthermore, the solid mixture A in the second step is divided into three parts according to a ratio, and the mass ratio of the first part to the second part is 0.2:0.2-0.4:0.6-0.4; the first part of the solid mixture A is used to make the skeleton material of the biomass char binder; the second part is used to dehydrate to obtain the water source for the subsequent CO-water supercritical process; the third part is used to prepare the main material of the carbon; the hydrolysis process in the second step is to add KOH hydrolyzing agent and ammonia water, and the first part of the solid mixture A is mixed with KOH, ammonia water and water in a mass ratio of 1:0.1-0.3:0.05-0.1:1-10, and after mixing evenly, a hydrolysis and fermentation process is carried out for 3-10 days.

[0019] Furthermore, the heating rate of the pyrolysis in the third step is 3-5°C / min, and the residence time after heating to the final temperature of 650°C is 1-3h.

[0020] Furthermore, in the fourth step, the mass ratio of the liquid C, the solid mixture D and the tar E is 5:1:1-5.

[0021] Furthermore, the tar L in the seventh step can be used as the tar E in the fourth step to enter the CO-water supercritical hydrogenation reaction, and finally the tar H in the hydrodeoxygenation and desulfurization process is collected.

[0022] Furthermore, the process of the CO-water supercritical hydrogenation reaction in the fourth step is: CO gas is initially introduced under normal temperature and oxygen-free conditions to make the pressure in the reactor reach 5MPa; when the temperature starts to rise, CO is introduced and the pressure is adjusted to 5-10MPa, and CO is supplemented before 250°C, and the space velocity of CO is 10-500h -1 The CO-water critical reactor is heated at a heating rate of 3-5°C / min, and finally reaches the critical temperature of 340±10°C of the CO-water system, and stays at the critical temperature and critical pressure of 10-20MPa for 1-5h.

[0023] Furthermore, in the fifth step, the mixing ratio of the solid mixture B and the biomass solid part G is 1:1-2.

[0024] Furthermore, in the sixth step, the mixing ratio of the solid mixture A to the binder J is 1:5-10; in the hot melt pressure molding, the extrusion pressure of 100-1000KN mainly squeezes out the liquid part of the tar H, and at the same time makes the biomass form block-shaped carbon.

[0025] Furthermore, during the seventh step of pyrolysis, the tar L includes the tar E remaining in the solid part G in the fifth step; the heating rate of pyrolysis is 3-5°C / min, and the residence time after heating to the final temperature of 650°C is 1-3h.

[0026] The beneficial effects of the present invention are as follows:

[0027] The present invention does not use hydrogen as a raw material, but uses active hydrogen generated by the reaction of CO and water to complete the hydrogenation process of super / subcritical biomass and biomass tar at 340°C.

[0028] In the process of preparing clean carbon from biomass, a binder is required. The present invention utilizes a super / subcritical system to hydrolyze and transform the biomass so that it has a binder function and participates in the subsequent preparation of biomass carbon. Biomass oil is prepared by pyrolysis of biomass such as straw and Chinese medicine residue, and the biomass oil is subjected to a deoxygenation and hydrogenation process to reduce the oxygen-containing functional groups and hydrogenate some sulfur compounds. The strength of the obtained biomass carbon must meet the requirements of >550N / piece, and the porosity must be ≥20%. The process of preparing biomass oil and clean carbon by pyrolysis of biomass such as straw and Chinese medicine residue is used to realize the hydrogenation and thickening of waste biomass solids and the hydrogenation, deoxygenation and desulfurization of biomass tar, thereby realizing the green and low-carbon circular development of biomass. DETAILED DESCRIPTION

[0029] Example 1

[0030] In the first step, biomass including any one or any combination of straw and Chinese medicine residue in any proportion is selected, and it is crushed and screened to obtain a solid mixture A with a particle size of 1-10 mm after crushing and screening, and the water content of the solid mixture A exceeds 20wt%, and the mass fraction is 100 parts.

[0031] In the second step, the solid mixture A obtained in the first step is divided into three parts according to the proportion, and the mass ratio of the first, second and third parts is 0.2:0.2:0.6. The first part of solid mixture A is used to make the skeleton material of biomass type char binder. The hydrolysis process is to add KOH hydrolyzing agent and ammonia water. The first part of solid mixture A is mixed with KOH, ammonia water and water in a mass ratio of 1:0.1:0.05:5. After mixing evenly, a hydrolysis and fermentation process is carried out for 3 days, and solid mixture B and liquid C are obtained by filtration; the second part of solid mixture A is used to dehydrate to obtain the water source for the subsequent CO-water supercritical process; the third part of solid mixture A is used to prepare the main material of type carbon.

[0032] In the third step, the second solid mixture A prepared in the second step is heated to 650°C at a heating rate of 3°C / min for pyrolysis. The residence time after reaching the final temperature of 650°C is 3h. The solid mixture D, tar E and pyrolysis gas F after the pyrolysis are collected.

[0033] In the fourth step, the liquid C prepared in the second step, the solid mixture D obtained in the third step, and the tar E prepared in the third step are mixed and placed in a CO-water supercritical reactor. The mass ratio of liquid C, solid mixture D and tar E is 5:1:1, and the CO-water supercritical hydrogenation reaction of tar is completed. The process of CO-water supercritical hydrogenation reaction is: CO gas is initially introduced under normal temperature and oxygen-free conditions to make the pressure in the reactor reach 5MPa. When the temperature starts to rise, CO gas is introduced and the pressure is adjusted to 5MPa. CO is supplemented before 250°C, and the CO space velocity is 500h -1 The CO-water critical reactor is heated at a heating rate of 3°C / min, and finally reaches the critical temperature of 340°C of the CO-water system, and stays at the critical temperature and 20MPa critical pressure for 1 h. In the seventh step, the tar L can be used as the tar E in the fourth step to enter the CO-water supercritical hydrogenation reaction, and finally obtain the hydrogenated biomass solid part G and the tar H that completes the hydrodeoxygenation and desulfurization process.

[0034] In the fifth step, the solid mixture B obtained in the second step and the biomass solid part G obtained in the fourth step are mixed evenly in a ratio of 1:1 to form a binder J.

[0035] In the sixth step, the third solid mixture A prepared in the second step and the binder J obtained in the fifth step are uniformly mixed in a ratio of 1:5, hot melt pressure molding is completed, and the residual tar H is extruded at an extrusion pressure of 1000KN to obtain the biomass block carbon K.

[0036] In the seventh step, the biomass carbon J is heated to 650°C at a heating rate of 3°C / min and kept for 1-3 hours to collect the biomass carbon K, tar L and pyrolysis gas M after pyrolysis. Among them, the tar L includes the tar E remaining in the solid part G in the fifth step.

[0037] Example 2

[0038] In the first step, biomass including any one or any combination of straw and Chinese medicine residue in any proportion is selected, and it is crushed and screened to obtain a solid mixture A with a particle size of 10-20 mm after crushing and screening, and the water content of the solid mixture A exceeds 20wt%, and the mass fraction is 100 parts.

[0039] In the second step, the solid mixture A obtained in the first step is divided into three parts according to the proportion, and the mass ratio of the first and second parts is 0.2: 0.4: 0.4. The first part of solid mixture A is used to make the skeleton material of biomass type char binder. The hydrolysis process is to add KOH hydrolyzing agent and ammonia water. The first part of solid mixture A is mixed with KOH, ammonia water and water in a mass ratio of 1: 0.3: 0.1: 10. After mixing evenly, a hydrolysis and fermentation process is carried out for 3-10 days, and a solid mixture B and liquid C are obtained by filtration; the second part of solid mixture A is used to dehydrate to obtain the water source for the subsequent CO-water supercritical process; the third part of solid mixture A is used to prepare the main material of type carbon.

[0040] In the third step, the second solid mixture A prepared in the second step is heated to 650°C at a heating rate of 5°C / min for pyrolysis. The residence time after reaching the final temperature of 650°C is 3h. The solid mixture D, tar E and pyrolysis gas F after the pyrolysis are collected.

[0041] In the fourth step, the liquid C prepared in the second step, the solid mixture D obtained in the third step, and the tar E prepared in the third step are mixed and placed in a CO-water supercritical reactor. The mass ratio of liquid C, solid mixture D and tar E is 5:1:3, and the CO-water supercritical hydrogenation reaction of tar is completed. The process of CO-water supercritical hydrogenation reaction is: CO gas is initially introduced under normal temperature and oxygen-free conditions to make the pressure in the reactor reach 5MPa. When the temperature starts to rise, CO is introduced and the pressure is adjusted to 5-10MPa. CO is supplemented before 250°C, and the CO space velocity is 10-500h -1The CO-water critical reactor is heated at a heating rate of 3-5°C / min, and finally reaches the critical temperature of 340±10°C of the CO-water system, and stays at the critical temperature and 20MPa critical pressure for 5h. In the seventh step, the tar L can be used as the tar E in the fourth step to enter the CO-water supercritical hydrogenation reaction, and finally obtain the hydrogenated biomass solid part G and the tar H that completes the hydrodeoxygenation and desulfurization process.

[0042] In the fifth step, the solid mixture B obtained in the second step and the biomass solid part G obtained in the fourth step are mixed evenly in a ratio of 1:1.5 to form a binder J.

[0043] In the sixth step, the third solid mixture A prepared in the second step and the binder J obtained in the fifth step are evenly mixed in a ratio of 1:10, hot melt pressure molding is completed, and the residual tar H is extruded at an extrusion pressure of 500KN to obtain the biomass block carbon K.

[0044] In the seventh step, the biomass carbon J is heated to 650°C at a heating rate of 3-5°C / min and kept for 1 hour to collect the biomass carbon K, tar L and pyrolysis gas M after pyrolysis. Among them, the tar L includes the tar E remaining in the solid part G in the fifth step.

[0045] Example 3

[0046] In the first step, biomass including any one or any combination of straw and Chinese medicine residue in any proportion is selected, and it is crushed and screened to obtain a solid mixture A with a particle size of 10-20 mm after crushing and screening, and the water content of the solid mixture A exceeds 20wt%, and the mass fraction is 100 parts.

[0047] In the second step, the solid mixture A obtained in the first step is divided into three parts according to the proportion, and the mass ratio of the first and second parts is 0.2:0.3:0.5. The first part of solid mixture A is used to make the skeleton material of biomass type char binder. The hydrolysis process is to add KOH hydrolyzing agent and ammonia water. The first part of solid mixture A is mixed with KOH, ammonia water and water in a mass ratio of 1:0.2:0.075:1. After mixing evenly, a hydrolysis and fermentation process is carried out for 3-10 days, and a solid mixture B and liquid C are obtained by filtration; the second part of solid mixture A is used to dehydrate to obtain the water source for the subsequent CO-water supercritical process; the third part of solid mixture A is used to prepare the main material of type carbon.

[0048] In the third step, the second solid mixture A prepared in the second step is heated to 650°C at a heating rate of 3-5°C / min for pyrolysis. The residence time after reaching the final temperature of 650°C is 1-3h. The solid mixture D, tar E and pyrolysis gas F after the pyrolysis are collected.

[0049] In the fourth step, the liquid C prepared in the second step, the solid mixture D obtained in the third step, and the tar E prepared in the third step are mixed and placed in a CO-water supercritical reactor. The mass ratio of liquid C, solid mixture D and tar E is 5:1:4, and the CO-water supercritical hydrogenation reaction of tar is completed. The process of CO-water supercritical hydrogenation reaction is: CO gas is initially introduced under normal temperature and oxygen-free conditions to make the pressure in the reactor reach 5MPa. When the temperature starts to rise, CO is introduced and the pressure is adjusted to 7.5 MPa. CO is supplemented before 250°C, and the space velocity of CO is 10h -1 The CO-water critical reactor is heated at a heating rate of 4°C / min, and finally reaches the critical temperature of 340±10°C of the CO-water system, and stays at the critical temperature and 15MPa critical pressure for 3h. In the seventh step, the tar L can be used as the tar E in the fourth step to enter the CO-water supercritical hydrogenation reaction, and finally obtain the hydrogenated biomass solid part G and the tar H that completes the hydrodeoxygenation and desulfurization process.

[0050] In the fifth step, the solid mixture B obtained in the second step and the biomass solid part G obtained in the fourth step are mixed evenly in a ratio of 1:2 to form a binder J.

[0051] In the sixth step, the third solid mixture A prepared in the second step and the binder J obtained in the fifth step are uniformly mixed in a ratio of 1:7.5, and hot melt pressure molding is completed. The residual tar H is extruded at an extrusion pressure of 100KN to obtain the biomass block carbon K.

[0052] In the seventh step, the biomass carbon J is heated to 650°C at a heating rate of 4°C / min and kept for 2 hours to collect the biomass carbon K, tar L and pyrolysis gas M after pyrolysis. Among them, the tar L includes the tar E remaining in the solid part G in the fifth step.

Claims

1. A biomass viscosity modification and tar hydrogenation process, characterized in that: The steps include: In the first step, the biomass is crushed and screened to obtain a solid mixture A; In the second step, the solid mixture A obtained in the first step is divided into three parts according to a ratio, the first part of the solid mixture A is subjected to hydrolysis and fermentation treatment, and a solid mixture B and a liquid C are obtained by filtration; The third step is to heat the second solid mixture A prepared in the second step to 650° C. for pyrolysis, and collect the solid mixture D, tar E and pyrolysis gas F after pyrolysis. The fourth step is to mix the liquid C prepared in the second step, the solid mixture D obtained in the third step, and the tar E prepared in the third step, and put them into a CO2-water supercritical reactor to complete the CO2-water supercritical hydrogenation reaction of the tar, and finally obtain the hydrogenated biomass solid part G and the tar H that has completed the hydrodeoxygenation and desulfurization process; The fifth step is to mix the solid mixture B obtained in the second step with the biomass solid part G obtained in the fourth step to form a binder J; Step 6: Evenly mix the third solid mixture A prepared in the second step with the binder J obtained in the fifth step, complete hot melt press molding, and squeeze out the residual tar H to obtain biomass carbon K; In the seventh step, the biomass carbon J is heated to 650° C., and the biomass carbon K, tar L and pyrolysis gas M after pyrolysis are collected.

2. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: In the first step, the biomass comprises any one of straw and Chinese medicinal residue or any combination of the two in any proportion, the moisture content of the solid mixture A exceeds 20wt%, the mass fraction is 100 parts, and the particle size of the solid mixture A after crushing and screening is 1-20mm.

3. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: The solid mixture A in the second step is divided into three parts according to a ratio, and the mass ratio of the first part to the second part is 0.2:0.2-0.4:0.6-0.4; the first part of the solid mixture A is used to make the skeleton material of the biomass char binder; the second part is used to dehydrate to obtain the water source for the subsequent CO-water supercritical process; the third part is used to prepare the carbon material; the hydrolysis process in the second step is to add KOH hydrolyzing agent and ammonia water, and the first solid mixture A is mixed with KOH, ammonia water and water in a mass ratio of 1:0.1-0.3:0.05-0.1:1-10, and after mixing evenly, a hydrolysis and fermentation process is carried out for 3-10 days.

4. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: The heating rate of the pyrolysis in the third step is 3-5°C / min, and the residence time after heating to the final temperature of 650°C is 1-3h.

5. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: The mass ratio of the liquid C, the solid mixture D and the tar E in the fourth step is 5:1:1-5.

6. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: In the seventh step, tar L enters the CO-water supercritical hydrogenation reaction as tar E in the fourth step, and finally tar H from the hydrodeoxygenation and desulfurization process is collected.

7. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: The process of the CO-water supercritical hydrogenation reaction in the fourth step is: CO gas is initially introduced under normal temperature and oxygen-free conditions to make the pressure in the reactor reach 5MPa; when the temperature starts to rise, CO is introduced and the pressure is adjusted to 5-10MPa, and CO is supplemented before 250°C, and the space velocity of CO is 10-500h -1 The CO-water critical reactor is heated at a heating rate of 3-5°C / min, and finally reaches the critical temperature of 340±10°C of the CO-water system, and stays at the critical temperature and critical pressure of 10-20MPa for 1-5h.

8. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: In the fifth step, the mixing ratio of the solid mixture B and the biomass solid part G is 1:1-2.

9. The process for thickening and modifying biomass and hydrogenating and utilizing its tar according to claim 1, characterized in that: In the sixth step, the mixing ratio of the solid mixture A to the binder J is 1:5-10; in the hot melt pressure molding, the liquid part of the tar H is squeezed out with an extrusion pressure of 100-1000KN, and the biomass is formed into block-shaped carbon.

10. The biomass viscosity-enhancing modification and tar hydrogenation process according to claim 1, characterized in that: During the seventh step of pyrolysis, the tar L includes the tar E remaining in the solid part G in the fifth step; the heating rate of pyrolysis is 3-5°C / min, and the residence time after heating to the final temperature of 650°C is 1-3h.