A method and system for producing synthesis gas from biomass

Abstract

The present invention discloses a method and system for preparing synthesis gas from biomass, comprising the following steps: (1) uniformly mixing a first catalyst, wood vinegar and water to obtain a pretreatment solution; (2) adding a biomass raw material to the pretreatment solution for impregnation and drying to obtain a pretreated biomass raw material; (3) the pretreated biomass raw material enters a carbonization reactor for carbonization reaction; (4) the solid material obtained after the carbonization reaction is uniformly mixed with a second catalyst and then enters a gasification reactor for gasification reaction to obtain synthesis gas. The present invention uses biomass as a raw material to prepare a synthesis gas product through a carbonization-gasification combined process, and has the advantages of simple process, high synthesis gas yield and high energy utilization.

Description

Technical Field

[0001] The present invention belongs to the technical field of renewable energy, and in particular relates to a method and system for preparing synthesis gas using biomass as raw material. Background Art

[0002] Faced with the current situation that my country is vigorously developing renewable energy and gradually reducing its dependence on traditional fossil energy, obtaining high-quality liquid fuels and chemicals from biomass agricultural and forestry wastes has gradually become a development trend. Biomass gasification synthesis of liquid fuel technology is a complete set of integrated technologies that uses thermochemical methods to gasify biomass to produce raw gas, then purifies the gas and adjusts its components to obtain high-quality synthesis gas, and then uses catalytic technology to synthesize liquid fuels and chemicals after pressurization. The main products include hydrocarbon fuels (such as gasoline, diesel, etc.) and oxygen-containing compound liquid fuels (such as low-carbon mixed alcohols and dimethyl ether, etc.). Because this technology has wide raw material adaptability, high product purity and cleanliness, and no SO after combustion, it is very suitable for the production of high-quality synthetic gas. X and NO X Due to its emission advantages, there is a huge market demand for engine fuel and civilian fuel, and the prospects are very promising.

[0003] The preparation of synthesis gas by direct steam gasification of biomass has very strict requirements on the gasifier. At the same time, the crude synthesis gas produced has a high tar content and requires a very complex gas purification process. Patent CN110205162A provides a biomass synthesis gas production method and device. The biomass gasification temperature is as high as 900°C, and the energy consumption is very high. Compared with the direct biomass gasification technology, the pyrolysis process of biomass and the gasification process of coke are connected in series. The composition of the gas product can be more accurately controlled according to the characteristics of the product. Patent CN 109181781 A adopts a pyrolysis-gasification mode to gasify seaweed and agricultural and forestry biomass together, and then uses the potassium, calcium and sodium rich in seaweed coke as a biocoke gasification catalyst. The temperature of the seaweed in the pyrolysis and coke gasification reaction sections is very high, and the purity of the synthesis gas product is relatively low. Patent CN111378510A provides a method and system for preparing synthesis gas using biomass, including biomass cracking process, tar cracking, low carbon hydrocarbon reforming, biocoke gasification and other processes. The process is lengthy, the energy consumption of the entire process is high, and the synthesis gas content of the product is relatively low.

[0004] The prospects for the use of biomass-based liquid fuels and chemicals ultimately depend on cost competitiveness, so reducing costs has become a key link in their economics. Therefore, the development of new biomass thermochemical conversion processes to produce syngas, cheap catalysts, and the reduction of process energy consumption have become the focus and difficulty of research. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the purpose of the present invention is to provide a method and system for producing synthesis gas from biomass, which uses biomass as raw material to prepare synthesis gas products through a carbonization-gasification combined process, and has the advantages of simple process, high synthesis gas yield and high energy utilization rate.

[0006] The first aspect of the present invention provides a method for producing synthesis gas from biomass according to a first embodiment, comprising the following steps:

[0007] (1) mixing the first catalyst, wood vinegar and water to obtain a pretreatment solution after mixing evenly;

[0008] (2) adding the biomass raw material to the pretreatment solution obtained in step (1), impregnating and drying the biomass raw material to obtain the pretreated biomass raw material;

[0009] (3) the pretreated biomass raw material from step (2) enters the carbonization reactor for carbonization reaction;

[0010] (4) The solid material obtained after the carbonization reaction is mixed with the second catalyst, and after being evenly mixed, it enters the gasification reactor and is activated. After the activation is completed, it contacts with water vapor for gasification reaction to obtain synthesis gas.

[0011] The second aspect of the present invention provides a method for producing synthesis gas from biomass according to a second embodiment, comprising the following steps:

[0012] (1) mixing the first catalyst, wood vinegar and water to obtain a pretreatment solution after mixing evenly;

[0013] (2) adding the biomass raw material to the pretreatment solution obtained in step (1), impregnating and drying the biomass raw material to obtain the pretreated biomass raw material;

[0014] (3) The pretreated biomass raw material from step (2) is mixed with the activated carbon, and after being evenly mixed, enters into a carbonization reactor for carbonization reaction;

[0015] (4) The solid material obtained after the carbonization reaction is mixed with the second catalyst, and after being evenly mixed, it enters the gasification reactor and is activated. After the activation is completed, it contacts with water vapor for gasification reaction to obtain synthesis gas.

[0016] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, in step (1), the first catalyst is a transition metal compound, and the transition metal compound can be a transition metal inorganic salt and / or a transition metal organic salt, and further can be one or more of transition metal nitrates, transition metal hydrochlorides, transition metal sulfates, and transition metal acetates, and further can be selected from one or more of nickel nitrate, ferric nitrate, cobalt nitrate, copper nitrate, zinc nitrate, ferric chloride, ferrous chloride, nickel chloride, cobalt chloride, cupric chloride, zinc chloride, ferric sulfate, ferrous sulfate, nickel sulfate, cobalt sulfate, copper sulfate, zinc sulfate, nickel acetate, cobalt acetate, copper acetate, and zinc acetate, and is preferably one or more of nickel nitrate, ferric nitrate, cobalt nitrate, copper nitrate, ferrous chloride, nickel chloride, cobalt chloride, ferrous sulfate, nickel sulfate, cobalt sulfate, nickel acetate, and cobalt acetate.

[0017] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the wood vinegar in step (1) is the supernatant obtained by standing and separating the crude wood vinegar produced during the dry distillation or pyrolysis of the biomass raw material, and has a density of 0.9 to 1.1 g / cm 3 , pH value is 2.5~4.5, and the organic matter content is 1wt%~20wt%.

[0018] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the weight ratio of the wood vinegar in step (1) to the biomass raw material in step (2) is 1:3 to 5:1, preferably 1:3 to 3:1.

[0019] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the mass ratio of the water in step (1) to the biomass raw material in step (2) is 3:1 to 1:10.

[0020] Furthermore, in the above-mentioned method for producing synthesis gas by biomass carbonization-gasification, the weight ratio of the biomass raw material to the petroleum coke-based activated carbon is 1:0.3 to 1:2, preferably 1:0.3 to 1:1.5.

[0021] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the biomass raw material in step (2) is any biomass containing lignocellulose, such as forestry residues or agricultural residues, and can be one or more of straw, rice husk, wheat straw, wood block, leaves, and branches. The shape of the biomass raw material can be any shape such as flake, round, cylindrical, conical, square, irregular, etc., and the largest dimension of the raw material does not exceed 30 mm, preferably 1 to 25 mm.

[0022] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the weight ratio of the biomass raw material in step (2) to the first catalyst in step (1) is 60:1 to 10:1.

[0023] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the drying temperature in step (2) is 40 to 100° C., and the drying is preferably carried out under vacuum conditions.

[0024] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the pretreated biomass raw material in step (3) is subjected to pyrolysis and carbonization reaction in a carbonization reactor. Furthermore, the reaction conditions of the carbonization reactor are as follows: the reaction temperature is 200 to 550°C, preferably 200 to 500°C; the reaction time is 0.2 to 2h, preferably 0.2 to 1h.

[0025] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the activated carbon in step (3) is one or more of biomass-based activated carbon, asphalt-based activated carbon, and petroleum coke-based activated carbon, preferably asphalt-based activated carbon and / or petroleum coke-based activated carbon with a dense structure. Petroleum coke-based activated carbon refers to activated carbon with a rich pore structure obtained by physical and / or chemical activation process using petroleum coke as raw material. Further preferably, the petroleum coke-based activated carbon is an activated carbon product obtained by activating petroleum coke produced in a coking process, and has a specific surface area of ​​1200 to 3000 m 2 / g, the pore size is generally 0.5-8nm, and the mesoporosity is 10%-30%. For those skilled in the art, the petroleum coke physics and / or activation process is well known and can be selected from existing methods as needed.

[0026] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the solid material obtained after the carbonization reaction in step (4) generally includes biochar, ash, transition metal elements, transition metal oxides, and transition metal compounds.

[0027] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the second catalyst in step (4) is an alkali metal sulfate, and the alkali metal sulfate can be selected from one or more of lithium sulfate, sodium sulfate, potassium sulfate, rubidium sulfate, cesium sulfate, and francium sulfate, preferably sodium sulfate and / or potassium sulfate.

[0028] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the weight ratio of the second catalyst in step (4) to the biomass raw material in step (2) is 1:50 to 1:10.

[0029] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the solid material obtained after the carbonization reaction in step (4) can be mixed with the second catalyst by dry mixing; the dry mixing method can specifically be that the solid material obtained after the carbonization reaction is pushed and turned up and down in a screw propeller before entering the gasification reactor to achieve uniform mixing with the second catalyst, and the two are used as feed to the gasification reactor.

[0030] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the solid material obtained after the carbonization reaction in step (4) is mixed evenly with the second catalyst and then added to the gasification reactor, and first activated at a temperature of 600 to 900° C., preferably 650 to 850° C.; the activation is carried out under a reducing atmosphere, and the reducing atmosphere is any one or more of hydrogen, a hydrogen-helium mixed gas, a hydrogen-nitrogen mixed gas, and a hydrogen-water vapor mixed gas, and the volume proportion of hydrogen in the mixed gas can generally be 5% to 30%.

[0031] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the gasification reaction temperature in step (4) is 700-950°C, preferably 750-900°C; and the reaction time is 20-90 min, preferably 20-75 min.

[0032] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the mass ratio of water vapor to biochar in step (4) is 0.1 to 10, preferably 0.2 to 8.

[0033] Further, in the above-mentioned method for preparing synthesis gas from biomass, the reactions occurring in the carbonization reactor are mainly biomass carbonization reaction and biomass pyrolysis reaction, and the transition metal compound is thermally decomposed to generate transition metal oxides during the reaction, or the transition metal oxides react with the generated carbon, hydrogen and other reducing substances to generate in-situ active transition metal single substances highly dispersed on the surface of biochar, so the solid matter at the outlet of the carbonization reactor may contain transition metal salts, transition metal oxides, and transition metal single substances in different proportions. The petroleum coke-based activated carbon basically does not participate in the reaction during the pyrolysis and carbonization of biomass. The rich pore structure and large pore volume of the petroleum coke-based activated carbon can realize the in-situ capture of the tar components produced by pyrolysis, especially the heavy tar components rich in polycyclic aromatic hydrocarbons, which not only reduces the tar content in the pyrolysis gas, but also provides sufficient condensation reaction space for the heavy tar components, and deposits amorphous coke on the inner surface of the petroleum coke-based activated carbon to increase the carbonization yield.

[0034] Furthermore, in the above-mentioned method of producing synthesis gas from biomass, in the gasification reactor, during the activation process of the second catalyst, the solid material from the carbonization reactor containing transition metal salts, transition metal oxides, and transition metal elements in different proportions is fully reduced by the reducing gas or the hot biochar with strong reducing properties at a higher reaction temperature to generate active elemental transition metals under the reaction conditions. The appearance of active elemental transition metals can significantly promote the process of reducing alkali metal sulfates to generate alkali metal sulfides, promote the appearance of low-melting point eutectics at a lower temperature, and reduce the gasification reaction temperature. In the gasification reactor, the petroleum coke-based activated carbon itself will react in small amounts, but it has no effect on the properties of the synthesis gas product. The biochar gasification stage provides sufficient space for the amorphous biochar on the inner surface of the activated carbon to react with water vapor, thereby improving the gasification reaction conversion rate of the biochar and the synthesis gas yield.

[0035] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, in the gasification reactor, during the activation process of the second catalyst, the melting point of the alkali metal sulfate in an inert atmosphere is relatively high. In a reducing atmosphere, the alkali metal sulfate is heated to a certain temperature, and is reduced to an alkali metal sulfide by hydrogen. The alkali metal sulfide and the alkali metal sulfate will form a low-melting point eutectic in the atmosphere of biochar water vapor gasification. The low-melting point eutectic has stronger fluidity than pure alkali metal sulfate or pure transition metal salt at the reaction temperature. Therefore, the wettability and adhesion of the catalyst to the surface of the carbon particles are significantly enhanced, the contact between the catalyst and the carbon microcrystals is more sufficient, the gasification conversion rate of the biochar is greatly improved, and the water vapor gasification performance is improved. In addition to having a significant promoting effect on the gasification reaction activity of the biochar, the low-melting point eutectic mixture of the alkali metal sulfate and the alkali metal sulfide also plays a good role in the fixation of the alkali metal, greatly reducing the volatilization of the alkali metal.

[0036] Furthermore, in the above-mentioned method for producing synthesis gas from biomass, the gaseous material obtained after the carbonization reaction is a volatile gas, which mainly includes combustible gases generated during biomass pyrolysis and carbonization, volatile tar components, and other gases escaping from the carbonization reactor in gaseous form.

[0037] Furthermore, in the above-mentioned method of producing synthesis gas from biomass, the gaseous material from the carbonization reactor can enter the burner for full combustion (the full combustion generally means that the combustion products are only carbon dioxide and water), and the heat generated by the combustion of the volatile gas is supplied to the steam generator, the carbonization reactor, and the gasification reactor, with priority given to the steam generator, and the excess heat is used to assist the carbonization reactor and the gasification reactor.

[0038] A third aspect of the present invention provides a system for producing synthesis gas from biomass, the system comprising

[0039] a pretreatment reactor for receiving and mixing the first catalyst, wood vinegar, water and biomass feedstock;

[0040] A dryer, which is used to receive and dry the mixed material from the pretreatment reactor to obtain a pretreated biomass raw material;

[0041] A carbonization reactor is used to receive the pretreated biomass raw material and the optional activated carbon from the dryer. The pretreated biomass raw material and the activated carbon are evenly mixed and then enter the carbonization reactor for carbonization reaction to obtain a solid material after the reaction;

[0042] The gasification reactor is used to receive the solid material and the second catalyst obtained from the carbonization reactor. The solid material and the second catalyst enter the gasification reactor for activation. After the activation is completed, they are in contact with water vapor for gasification reaction to obtain synthesis gas.

[0043] Furthermore, in the above-mentioned biomass-to-syngas system, the pretreatment reactor may adopt any one or more of the existing mechanical agitators, immersion agitators, propeller agitators, vertical agitators, etc. in the art.

[0044] Furthermore, in the above-mentioned biomass-to-syngas system, the dryer may be any one of the existing devices in the art that can achieve a drying function, specifically any one or more of a forced air drying oven, a vacuum drying oven, a hot air circulation oven, and the like.

[0045] Furthermore, in the above-mentioned biomass-to-syngas system, the carbonization reactor can adopt the existing biomass microwave vertical fixed bed reactor, biomass spiral propulsion carbonization reactor, and biomass rotary furnace carbonization reactor in the art.

[0046] Furthermore, in the above-mentioned biomass-to-syngas system, the gasification reactor can be any one of a microwave vertical fixed bed gasification reactor, a microwave fluidized bed gasification reactor, an electric heating vertical fixed bed reactor, and the like.

[0047] Furthermore, in the above-mentioned biomass-to-syngas system, the solid material obtained after the carbonization reaction is evenly mixed with the second catalyst by being pushed and flipped up and down in a screw propeller before entering the gasification reactor, and the solid material is used as feed for the gasification reactor.

[0048] Furthermore, the above-mentioned system for producing synthesis gas from biomass includes a steam generator for generating steam.

[0049] Furthermore, the above-mentioned biomass-to-syngas system includes a burner, and the gas material from the carbonization reactor enters the burner for full combustion (the full combustion generally refers to the combustion products being only carbon dioxide and water), and the heat generated by the gas combustion can be supplied to the steam generator, the carbonization reactor and the gasification reactor. It is preferred to supply the steam generator first, and the excess heat is used to assist the carbonization reactor and the gasification reactor.

[0050] Compared with the prior art, the method and system for producing synthesis gas from biomass of the present invention has the following advantages:

[0051] (1) In the method for producing synthesis gas from biomass of the present invention, a combined carbonization-gasification process is adopted. During the biomass carbonization process, the first catalyst forms a mixture of transition metal salts, transition metal oxides, and transition metal elements while catalyzing the pyrolysis and carbonization of biomass. The mixture can undergo a secondary reaction with the second catalyst used in the gasification reaction, thereby achieving effective coupling of the catalysts used in the two-stage process and greatly improving the reaction activity of the second catalyst.

[0052] (2) In the method for producing synthesis gas from biomass of the present invention, the plant organic composite substances such as acids, alcohols, ketones, aldehydes, etc. in the wood vinegar contain a certain amount of organic functional groups. On the one hand, the cellulose, hemicellulose and lignin in the biomass can be swelled by water through the impregnation and mixing process, thereby achieving complete infiltration of the aqueous substances; on the other hand, they can form certain complexes with transition metal ions in the pretreatment solution, thereby bringing the transition metal ions into the deep tissue of the biomass raw material during the infiltration process, achieving uniform distribution of the first catalyst on the surface and inside of the biomass raw material, improving the catalytic efficiency, and reducing the amount of the catalyst used.

[0053] (3) In the method for producing synthesis gas from biomass of the present invention, by adjusting the carbonization temperature and the residence time of the biomass in the carbonization furnace, the tar components produced by pyrolysis, especially the heavy tar components rich in polycyclic aromatic hydrocarbons, are captured in situ by utilizing the rich pore structure and large pore volume of the petroleum coke-based activated carbon. This not only reduces the tar content in the pyrolysis gas, but also allows the heavy tar components to be deposited and condensed into amorphous coke on the inner surface of the petroleum coke-based activated carbon, thereby maximizing the yield of biocoke. At the same time, the amorphous biocoke on the inner surface of the activated carbon is more likely to react with water vapor under gasification conditions, which is beneficial to further improve the gasification reaction conversion rate of biocoke and the synthesis gas yield.

[0054] (4) In the method of producing synthesis gas from biomass of the present invention, the volatile components generated in the carbonization reactor are sent to the burner in a high-temperature state for combustion, and the tar components are burned together with the combustible gas in a gaseous state to avoid environmental pollution caused by tar emissions and gas purification, prevent the problem of pipeline blockage caused by tar condensation, and solve the problem of oil and gas separation, greatly simplifying the reaction steps. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the carbonization reactor, and the gasification reactor for use, providing heat and reaction temperature for the synthesis gas preparation reaction, assisting the energy supply of the entire process, and ensuring the smooth operation of the reaction.

[0055] (5) In the method of producing synthesis gas from biomass of the present invention, the catalytic materials of the first catalyst and the second catalyst used are widely available and can be obtained from natural ores and seawater. They are inexpensive and greatly reduce the catalytic cost of steam gasification of biochar. They can be recycled and reused through a water-soluble method and can also be used as disposable catalysts.

[0056] (6) The present invention uses biomass raw materials to prepare synthesis gas, which broadens the application scope of biomass. The biomass is converted into synthesis gas products through a carbonization-gasification combined process, which has the advantages of simple process, high synthesis gas yield and high energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The figure is a schematic flow chart of the method for producing synthesis gas from biomass according to the present invention. DETAILED DESCRIPTION

[0058] The present invention is described in detail below with reference to the embodiments, but the protection scope of the present invention is not limited by the embodiments.

[0059] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0060] In this document, for the convenience of description, spatial relative terms such as "below", "below", "down", "above", "above", "upper", etc. may be used to describe the relationship between one element or feature and another element or feature in the accompanying drawings. It should be understood that the spatial relative terms are intended to include different directions of objects in use or operation in addition to the directions drawn in the drawings. For example, if the object in the figure is turned over, the elements described as being "below" or "below" other elements or features will be oriented "above" the elements or features. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used in this document should be interpreted accordingly.

[0061] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable.

[0062]

[0043] All numerical values ​​for parameters (eg, amounts or conditions) herein are to be understood as being modified in all instances by the term "about", whether or not "about" actually appears before the numerical value.

[0063] In the embodiments and comparative examples of the present invention, the wood vinegar used is from the pyrolysis process of bamboo willow. The upper layer of clear reddish-brown liquid obtained after the crude wood vinegar is left to stand has a density of 1.0258 g / cm 3 The pH value is 3.59. The main component is water (94.5wt%). The organic matter includes phenols (23.29wt%), organic acids (33.04wt%), ketones (25.60wt%), esters (5.12wt%), and aldehydes (4.29wt%). Some substances in the organic matter cannot be accurately classified and are recorded in the remainder.

[0064] In the embodiments and comparative examples of the present invention, the activated carbon used is petroleum coke-based activated carbon, and the preparation method is as follows: 100 g of petroleum coke (Jinling Petrochemical Refinery) is weighed, the petroleum coke is evenly mixed with 280 g of potassium hydroxide, and then activated at 800° C. for 40 min in a nitrogen atmosphere, cooled to room temperature, and the product is washed with dilute hydrochloric acid (concentration of 2 wt%) and deionized water in turn until neutral, and dried at 105° C. in a blast drying oven for 10 h to obtain petroleum coke-based activated carbon, and the specific surface area is 1896 m 2 / g, mesoporosity 18%, pore size range 0.5~8nm.

[0065] In this paper, the specific surface area and pore size distribution curves of the samples were obtained by nitrogen adsorption-desorption curves on a Micromeritics ASAP 2020 adsorption instrument. The operating temperature was -196 °C (liquid nitrogen temperature). The samples were pretreated with dehydration at 300 °C under nitrogen protection before testing. The specific surface area and pore size distribution were calculated by the BET method and the DFT method, respectively.

[0066] Example 1

[0067] Weigh 1.63 g of ferric nitrate (Fe(NO3)3·9H2O), add 93.9 g of wood vinegar and 3.13 g of water, stir to completely dissolve the ferric nitrate, add 31.3 g of chondrus crispus crushed material, stir to mix, soak for 12 h, and dry at 60 °C in vacuum for 8 h to obtain a biomass raw material loaded with ferric nitrate.

[0068] The biomass raw material loaded with iron nitrate is added to the carbonization reactor for reaction at a reaction temperature of 350°C. The biochar generated by the reaction is evenly mixed with 1.28g potassium sulfate in a screw feeder and enters the gasification reactor for water vapor gasification reaction. The reaction conditions are: reaction temperature 800°C, normal pressure, water vapor flux 0.3mL / min, syngas accounts for 95.2% of the gas at the outlet of the gasification reactor, and the syngas yield of the entire process is 527g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, carbonization reactor, and gasification reactor, providing guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the smooth operation of the reaction.

[0069] Example 2

[0070] Weigh 0.94 g of nickel acetate (Ni(CH3COO)2·4H2O), add 11.7 g of wood vinegar and 94.2 g of ultrapure water, stir to completely dissolve the nickel acetate, add 35.2 g of larch crushed material, stir and mix, soak for 12 h, and dry at 80 °C in vacuum for 5 h to obtain a biomass raw material loaded with nickel acetate.

[0071] The biomass raw material loaded with nickel nitrate is added to the carbonization reactor for reaction at a reaction temperature of 500°C. The biochar generated by the reaction is evenly mixed with 1.03g of sodium sulfate in a screw feeder and enters the gasification reactor for water vapor gasification reaction. The reaction conditions are: temperature 750°C, normal pressure, water vapor flux of 0.4mL / min, syngas accounts for 94.5% of the gas at the outlet of the gasification reactor, and the syngas yield of the entire process is 511g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, carbonization reactor, and gasification reactor, providing guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the smooth operation of the reaction.

[0072] Example 3

[0073] Weigh 0.98 g of cobalt nitrate (Co(NO3)2·6H2O), add 13.1 g of wood vinegar and 117.6 g of ultrapure water, stir to completely dissolve the cobalt nitrate, add 39.2 g of bamboo willow crushed material, stir to mix, soak for 12 h, and dry at 70 °C in vacuum for 6 h to obtain a biomass raw material loaded with cobalt nitrate.

[0074] The biomass raw material loaded with cobalt nitrate is added to the carbonization reactor for reaction at a reaction temperature of 550°C. The biochar generated by the reaction is evenly mixed with 1.41g potassium sulfate in a screw feeder and enters the gasification reactor for water vapor gasification reaction. The reaction conditions are: temperature 850°C, normal pressure, water vapor flux of 0.45mL / min, syngas accounts for 97.7% of the gas at the outlet of the gasification reactor, and the syngas yield of the entire process is 561g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, carbonization reactor, and gasification reactor, providing guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the smooth operation of the reaction.

[0075] Example 4

[0076] Weigh 1.37 g zinc nitrate (Zn(NO3)2·6H2O), add 78.4 g wood vinegar and 39.2 g ultrapure water, stir to completely dissolve the zinc nitrate, add 39.2 g walnut shell crushed material, stir and mix, soak for 12 h, and dry at 70 ° C in vacuum for 6 h to obtain a biomass raw material loaded with zinc nitrate.

[0077] The biomass raw material loaded with zinc nitrate is added to the carbonization reactor for reaction at a reaction temperature of 300°C. The biochar generated by the reaction is evenly mixed with 1.53g potassium sulfate in a screw feeder and enters the gasification reactor for water vapor gasification reaction. The reaction conditions are: temperature 950°C, normal pressure, water vapor flux of 0.55mL / min, and the proportion of syngas in the gas at the outlet of the gasification reactor is 96.7%. The syngas yield of the entire process is 553g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the carbonization reactor, and the gasification reactor, providing guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the smooth operation of the reaction.

[0078] Example 5

[0079] Weigh 0.88 g of ferrous sulfate (FeSO4·7H2O), add 60.7 g of wood vinegar and 50.4 g of ultrapure water, stir to completely dissolve the ferrous sulfate, add 36.6 g of hazelwood crushed material, stir to mix, soak for 12 h, and dry at 65 °C in vacuum for 7 h to obtain a biomass raw material loaded with ferrous sulfate.

[0080] The biomass raw material loaded with ferrous sulfate and 10.98g of petroleum coke-based activated carbon were added to the carbonization reactor for reaction at a reaction temperature of 400°C. The biocoke generated by the reaction was evenly mixed with 1.65g of potassium sulfate in a screw feeder and entered the gasification reactor for water vapor gasification reaction. The reaction conditions were: temperature 900°C, normal pressure, water vapor flux of 0.5mL / min, and the proportion of syngas in the gas at the outlet of the gasification reactor was 97.8%. The syngas yield of the entire process was 604g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor were sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components was supplied to the steam generator, the carbonization reactor, and the gasification reactor, providing a guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating was required to ensure the smooth operation of the reaction.

[0081] Example 6

[0082] Weigh 0.76 g of ferrous chloride (FeCl2·4H2O), add 40.2 g of wood vinegar and 70.9 g of ultrapure water, stir to completely dissolve the ferrous sulfate, add 32.5 g of one-year-old bamboo willow crushed material, stir to mix, soak for 12 h, and dry at 65 °C in vacuum for 7 h to obtain a biomass raw material loaded with ferrous chloride.

[0083] The biomass raw material loaded with ferrous chloride and 19.5g petroleum coke-based activated carbon were added to the carbonization reactor for reaction at a reaction temperature of 400°C. The biochar generated by the reaction was mixed evenly with 1.43g potassium sulfate in a screw feeder and entered the gasification reactor for water vapor gasification reaction. The reaction conditions were: temperature 900°C, normal pressure, water vapor flux of 0.45mL / min, syngas accounted for 98.7% of the gas at the outlet of the gasification reactor, and the syngas yield of the entire process was 639g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor were sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components was supplied to the steam generator, the carbonization reactor, and the gasification reactor, providing a guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating was required to ensure the smooth operation of the reaction.

[0084] Comparative Example 1

[0085] Weigh 1.63 g of ferric nitrate (Fe(NO3)3·9H2O), add 97.03 g of water, stir to completely dissolve the ferric nitrate, add 31.3 g of chopped spruce, stir to mix, soak for 12 h, and dry at 60 °C in vacuum for 8 h to obtain a biomass raw material loaded with ferric nitrate.

[0086] The biomass raw material loaded with ferric nitrate is added to the carbonization reactor for reaction at a reaction temperature of 350°C. The biochar generated by the reaction is mixed evenly with 1.28g potassium sulfate in a screw feeder and enters the gasification reactor for water vapor gasification reaction. The reaction conditions are: reaction temperature 800°C, normal pressure, water vapor flux 0.3mL / min, syngas accounts for 86.9% of the gas at the outlet of the gasification reactor, and the syngas yield of the entire process is 353g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, carbonization reactor, and gasification reactor, providing guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the smooth operation of the reaction.

[0087] Comparative Example 2

[0088] Weigh 35.2 g of larch crushed material, add 11.7 g of wood vinegar and 94.2 g of ultrapure water, stir and mix, soak for 12 h, and dry at 80° C. in vacuum for 5 h to obtain a biomass raw material.

[0089] The pretreated biomass raw materials are added to the carbonization reactor for reaction at a reaction temperature of 500°C. The biochar generated by the reaction is evenly mixed with 1.03g of sodium sulfate in a screw feeder and enters the gasification reactor for water vapor gasification reaction. The reaction conditions are: temperature 750°C, normal pressure, water vapor flux of 0.4mL / min, and the proportion of syngas in the gas at the outlet of the gasification reactor is 91.2%. The syngas yield of the entire process is 391g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner at a high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the carbonization reactor, and the gasification reactor, providing a guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the smooth operation of the reaction.

[0090] Comparative Example 3

[0091] Weigh 0.98 g of cobalt nitrate (Co(NO3)2·6H2O), add 13.1 g of wood vinegar and 117.6 g of ultrapure water, stir to completely dissolve the cobalt nitrate, add 39.2 g of bamboo willow crushed material, stir to mix, soak for 12 h, and dry at 70 °C in vacuum for 6 h to obtain a biomass raw material loaded with cobalt nitrate.

[0092] The biomass raw material loaded with cobalt nitrate is added to the carbonization reactor for reaction at a reaction temperature of 550°C. The biochar generated by the reaction enters the gasification reactor for water vapor gasification reaction. The reaction conditions are: temperature 850°C, normal pressure, water vapor flux of 0.45mL / min, and the proportion of syngas in the gas at the outlet of the gasification reactor is 77.6%. The syngas yield of the entire process is 221g syngas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner at high temperature for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the water vapor generator, carbonization reactor, and gasification reactor, providing guarantee for the energy supply of the entire process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the smooth operation of the reaction.

[0093] Comparative Example 4

[0094] Weigh 0.76 g of ferrous chloride (FeCl2·4H2O), add 40.2 g of wood vinegar and 70.9 g of ultrapure water, stir to completely dissolve the ferrous sulfate, add 32.5 g of one-year-old bamboo willow crushed material, stir to mix, soak for 12 h, and dry at 65 °C in vacuum for 7 h to obtain a biomass raw material loaded with ferrous chloride.

[0095] The biomass raw material loaded with ferrous chloride and 19.5 g of petroleum coke-based activated carbon (specific surface area 1163 m 2 / g, mesoporous rate 3%, pore size is mainly micropores below 1nm) is added to the carbonization reactor for reaction, the reaction temperature is 400℃, the biochar generated by the reaction is mixed evenly with 1.43g potassium sulfate in the screw feeder, and enters the gasification reactor for water vapor gasification reaction, the reaction conditions are: temperature 900℃, normal pressure, water vapor flux 0.45mL / min, synthesis gas accounts for 98.7% of the gas at the outlet of the gasification reactor, and the synthesis gas yield of the whole process is 593g synthesis gas / kg biomass. At the same time, the volatile components generated in the carbonization reactor are sent to the burner in a high temperature state for combustion. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, carbonization reactor, and gasification reactor, which provides guarantee for the energy supply of the whole process, greatly reduces the energy consumption of the process itself, and only a small amount of auxiliary heating is needed to ensure the smooth operation of the reaction.

[0096] It can be seen from the examples that after the biomass in the present invention is completely infiltrated with wood vinegar and water, cellulose, hemicellulose and lignin swell and deform to a certain extent, which is more conducive to the reaction. At the same time, the first catalyst is evenly distributed inside and outside the biomass raw material by the interaction between the transition metal salt and the wood vinegar. In the biomass carbonization process, by adjusting the temperature and the residence time of the biomass in the carbonization furnace, as much heavy tar as possible undergoes polycondensation reaction to ensure the maximum yield of biocoke. The biocoke gasification process uses two low-cost catalyst raw materials, transition metal salt and alkali metal sulfate, and catalyzes the biomass carbonization reaction through the transition metal salt. The transition metal oxides, transition metal single substances and other substances generated in the carbonization reaction continue to interact with the alkali metal sulfate during the biocoke gasification process, greatly improving the biocoke water vapor gasification activity of the alkali metal sulfate, not only overcoming the problem of low catalytic activity of cheap alkali metal halide catalytic materials, but also greatly reducing the cost of the reaction.

[0097] In the present invention, the volatile components generated in the carbonization reactor are sent to the burner in a high-temperature state for combustion, and the tar components are burned together with the combustible gas in a gaseous state to avoid environmental pollution caused by tar emissions and gas purification, prevent the problem of pipeline blockage caused by tar condensation, and avoid the complicated solution of oil and gas separation problems, greatly simplifying the reaction steps. Through the regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the carbonization reactor, and the gasification reactor to provide heat and reaction temperature for the hydrogen production reaction, provide most of the energy supply for the entire process, ensure the smooth operation of the reaction, and greatly reduce the energy consumption of the reaction. Therefore, the method for preparing synthesis gas from biomass disclosed in the present invention has the advantages of simple process, high synthesis gas yield, and high energy utilization rate, and has broad promotion value.

Claims

1. A method for producing synthesis gas from biomass, comprising the following steps: (1) mixing a first catalyst, wood vinegar and water to obtain a pretreatment solution after uniform mixing, wherein the first catalyst is a transition metal compound; the wood vinegar is a supernatant obtained by standing and separating crude wood vinegar produced during pyrolysis of biomass raw materials; (2) adding the biomass raw material to the pretreatment solution obtained in step (1), impregnating and drying the biomass raw material to obtain the pretreated biomass raw material; (3) the pretreated biomass raw material from step (2) enters the carbonization reactor for carbonization reaction; (4) The solid material obtained after the carbonization reaction is mixed with a second catalyst, and after being evenly mixed, it enters a gasification reactor and is activated. After the activation is completed, it is contacted with water vapor for a gasification reaction to obtain synthesis gas, and the second catalyst is an alkali metal sulfate.

2. A method for producing synthesis gas from biomass, comprising the following steps: (1) mixing a first catalyst, wood vinegar and water to obtain a pretreatment solution after uniform mixing, wherein the first catalyst is a transition metal compound; the wood vinegar is a supernatant obtained by standing and separating crude wood vinegar produced during pyrolysis of biomass raw materials; (2) adding the biomass raw material to the pretreatment solution obtained in step (1), impregnating and drying the biomass raw material to obtain the pretreated biomass raw material; (3) The pretreated biomass raw material from step (2) is mixed with activated carbon, and after being evenly mixed, enters into a carbonization reactor for carbonization reaction; (4) The solid material obtained after the carbonization reaction is mixed with a second catalyst, and after being evenly mixed, it enters a gasification reactor and is activated. After the activation is completed, it is contacted with water vapor for a gasification reaction to obtain synthesis gas, and the second catalyst is an alkali metal sulfate.

3. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The transition metal compound in step (1) is a transition metal inorganic salt and / or a transition metal organic salt.

4. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The transition metal compound in step (1) is one or more of transition metal nitrates, transition metal hydrochlorides, transition metal sulfates, and transition metal acetates.

5. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The transition metal compound in step (1) is selected from one or more of nickel nitrate, ferric nitrate, cobalt nitrate, copper nitrate, zinc nitrate, ferric chloride, ferrous chloride, nickel chloride, cobalt chloride, cupric chloride, zinc chloride, ferric sulfate, ferrous sulfate, nickel sulfate, cobalt sulfate, cupric sulfate, zinc sulfate, nickel acetate, cobalt acetate, cupric acetate, and zinc acetate.

6. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The transition metal compound in step (1) is selected from one or more of nickel nitrate, ferric nitrate, cobalt nitrate, copper nitrate, ferrous chloride, nickel chloride, cobalt chloride, ferrous sulfate, nickel sulfate, cobalt sulfate, nickel acetate and cobalt acetate.

7. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The density of the wood vinegar in step (1) is 0.9-1.1 g / cm 3 , pH value is 2.5~4.5, and organic matter content is 1wt%~20wt%.

8. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The weight ratio of the wood vinegar in step (1) to the biomass raw material in step (2) is 1:3 to 5:

1.

9. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The weight ratio of the wood vinegar in step (1) to the biomass raw material in step (2) is 1:3 to 3:

1.

10. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The mass ratio of water in step (1) to the biomass raw material in step (2) is 3:1 to 1:

10.

11. The method for producing synthesis gas from biomass according to claim 2, wherein: The activated carbon is petroleum coke-based activated carbon, and the weight ratio of the biomass raw material to the petroleum coke-based activated carbon is 1:0.3 to 1:

2.

12. The method for producing synthesis gas from biomass according to claim 2, wherein: The activated carbon is petroleum coke-based activated carbon, and the weight ratio of the biomass raw material to the petroleum coke-based activated carbon is 1:0.3 to 1:1.

5.

13. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The biomass raw material in step (2) is any biomass containing lignocellulose.

14. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The weight ratio of the biomass raw material in step (2) to the first catalyst in step (1) is 60:1 to 10:

1.

15. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The drying temperature in step (2) is 40 to 100°C.

16. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The drying in step (2) is carried out under vacuum conditions.

17. The method for producing synthesis gas from biomass according to claim 2, wherein: The activated carbon in step (3) is one or more of biomass-based activated carbon and asphalt-based activated carbon.

18. The method for producing synthesis gas from biomass according to claim 11, wherein: Petroleum coke-based activated carbon is an activated carbon product obtained by activating petroleum coke produced in the coking process. Its specific surface area is 1200-3000m 2 / g, pore size is 0.5~8nm, and mesoporosity is 10%~30%.

19. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: In step (4), the alkali metal sulfate is selected from one or more of lithium sulfate, sodium sulfate, potassium sulfate, rubidium sulfate, cesium sulfate and francium sulfate.

20. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: In step (4), the alkali metal sulfate is sodium sulfate and / or potassium sulfate.

21. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The weight ratio of the second catalyst in step (4) to the biomass raw material in step (2) is 1:50 to 1:

10.

22. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The solid material obtained after the carbonization reaction in step (4) is mixed evenly with the second catalyst and then added to the gasification reactor, and first activated at a temperature of 600 to 900° C. The activation is carried out under a reducing atmosphere, and the reducing atmosphere is any one or more of hydrogen, a hydrogen-helium mixed gas, a hydrogen-nitrogen mixed gas, and a hydrogen-water vapor mixed gas, and the volume proportion of hydrogen in the mixed gas is 5% to 30%.

23. The method for producing synthesis gas from biomass according to claim 22, wherein: The activation temperature is 650-850°C.

24. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: In step (4), the gasification reaction temperature is 700-950° C. and the reaction time is 20-90 min.

25. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: In step (4), the gasification reaction temperature is 750-900° C. and the reaction time is 20-75 min.

26. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: In step (4), the mass ratio of water vapor to biochar is 0.1 to 10.

27. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: In step (4), the mass ratio of water vapor to biochar is 0.2 to 8.

28. The method for producing synthesis gas from biomass according to claim 1 or 2, wherein: The gas material from the carbonization reactor enters the burner for full combustion, and the heat generated by the gas combustion is supplied to the steam generator, the carbonization reactor, and the gasification reactor.

29. A system for producing synthesis gas from biomass, the system comprising a pretreatment reactor for receiving and mixing the first catalyst, wood vinegar, water and biomass feedstock; A dryer is used to receive and dry the mixed material from the pretreatment reactor to obtain the pretreated biomass raw material; the wood vinegar is the supernatant obtained by standing and separating the crude wood vinegar produced during the pyrolysis of the biomass raw material; A carbonization reactor is used to receive the pretreated biomass raw materials from the dryer. The pretreated biomass raw materials enter the carbonization reactor for carbonization reaction to obtain solid materials after the reaction. The gasification reactor is used to receive the solid material and the second catalyst obtained from the carbonization reactor after the reaction. The solid material and the second catalyst enter the gasification reactor for activation. After the activation is completed, they are contacted with water vapor for gasification reaction to obtain synthesis gas.

30. A system for producing synthesis gas from biomass, the system comprising a pretreatment reactor for receiving and mixing the first catalyst, wood vinegar, water and biomass feedstock; A dryer is used to receive and dry the mixed material from the pretreatment reactor to obtain the pretreated biomass raw material; the wood vinegar is the supernatant obtained by standing and separating the crude wood vinegar produced during the pyrolysis of the biomass raw material; A carbonization reactor is used to receive the pretreated biomass raw materials and activated carbon from the dryer. After the pretreated biomass raw materials and activated carbon are evenly mixed, they enter the carbonization reactor for carbonization reaction to obtain solid materials after the reaction; The gasification reactor is used to receive the solid material and the second catalyst obtained from the carbonization reactor after the reaction. The solid material and the second catalyst enter the gasification reactor for activation. After the activation is completed, they are contacted with water vapor for gasification reaction to obtain synthesis gas.

31. The system for producing synthesis gas from biomass according to claim 29 or 30, wherein: A water steam generator is included for generating water steam.

32. The system for producing synthesis gas from biomass according to claim 29 or 30, wherein: The invention comprises a burner. The gas material from the carbonization reactor enters the burner for full combustion. The heat generated by the gas combustion is supplied to the steam generator, the carbonization reactor and the gasification reactor.

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