A biomass gasification fuel
By combining hydrothermal carbonization and alkaline metal oxide-modified catalytic carbon materials with a honeycomb ceramic catalytic reforming reactor, the biomass gasification process was optimized, solving the problems of high tar content, low syngas quality, and rapid catalyst deactivation, thus achieving efficient biomass resource conversion and energy utilization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG BAOXI ENERGY SAVING FUEL CO LTD
- Filing Date
- 2026-05-29
- Publication Date
- 2026-06-30
AI Technical Summary
Existing biomass gasification technologies suffer from problems such as high tar content leading to equipment blockage and damage, low syngas quality, rapid catalyst deactivation, improper connection between gasification and reforming sections, and severe energy loss.
In-situ catalytic gasification is achieved by using hydrothermal carbonization and catalytic carbon materials modified with alkaline metal oxides. This is combined with an integrated honeycomb ceramic catalytic reforming reactor and gas recycling to optimize the gasification process, reduce tar content, and improve syngas quality.
It significantly reduces tar content, increases the H2/CO ratio of syngas, extends catalyst life, reduces energy loss, and achieves efficient utilization of biomass resources.
Smart Images
Figure CN122302959A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of biomass energy technology, specifically to a biomass gasification fuel. Background Technology
[0002] Biomass gasification is a technology that converts biomass raw materials such as crop straw, sawdust, and fruit shells into combustible syngas through thermochemical conversion. It is an important pathway to realize the resource utilization of biomass. The syngas produced by biomass gasification can be used for power generation, heating, and in chemical industries such as methanol synthesis and Fischer-Tropsch synthesis.
[0003] However, existing biomass gasification technologies have the following problems: First, it has a high tar content.
[0004] The crude syngas produced by traditional gasification processes typically contains tar content as high as 100–5000 mg / Nm³. Tar condensation in pipelines can cause blockages, damage equipment in internal combustion engines or gas turbines, and increase the burden of wastewater treatment.
[0005] Second, the quality of the syngas is low.
[0006] Syngas obtained from conventional air gasification has a high N2 content (about 40-50%), low calorific value (only 4-7 MJ / Nm), and an uncontrollable N2 / CO ratio (usually between 0.4 and 0.8), making it difficult to meet the needs of downstream chemical synthesis.
[0007] Third, the catalyst deactivates rapidly.
[0008] Catalysts used in existing gasification processes (such as nickel-based catalysts) are prone to rapid deactivation due to carbon buildup and alkali metal poisoning, resulting in short service life and high operating costs.
[0009] Fourth, the gasification and reforming processes are not properly coordinated.
[0010] In traditional processes, the crude syngas produced by gasification needs to be cooled to remove tar before being heated and fed into the reforming reactor. This results in significant energy loss, and the tar polymerizes into polycyclic aromatic hydrocarbons (PAHs), which are more difficult to process, during the cooling process. Summary of the Invention
[0011] To address the above problems, this invention provides a biomass gasification fuel, which is achieved through the following technical solution.
[0012] A biomass gasification fuel, said gasification fuel being prepared by a method comprising the following steps: S1, the biomass raw material is subjected to hydrothermal carbonization to obtain a hydrothermal carbon intermediate; S2, the hydrothermal carbon intermediate is mixed with an alkaline metal oxide precursor solution and dried, and then pyrolyzed and activated at 500-700°C in an inert atmosphere to obtain an alkaline metal oxide modified catalytic carbon material. S3, the catalytic carbon material is fed into the gasification reactor and an in-situ catalytic gasification reaction is carried out in an oxygen-water vapor mixed gasification agent atmosphere to obtain crude syngas; S4, the crude syngas is passed into an integral honeycomb ceramic catalytic reforming reactor for in-situ reforming to obtain reformed gas; S5, the reformed gas is purified by passing it through a high-temperature filter and a desulfurization adsorber in sequence to obtain purified gas;
[0013] S6 recycles part of the purified gas back into the gasification reactor, and outputs the remaining purified gas as biomass gasification fuel.
[0014] As a further aspect of the present invention, in step S1, the hydrothermal carbonization treatment is carried out in a sealed environment at 180–260°C for 0.5–4 hours. The ratio of oxygen atoms to carbon atoms in the hydrothermal carbon intermediate is 0.20–0.40, and the specific surface area of the hydrothermal carbon intermediate is 100–350 m². 2 / g.
[0015] As a further embodiment of the present invention, according to claim 1, a biomass gasification fuel is characterized in that, in step S1, the hydrothermal carbonization treatment is carried out under acidic conditions with a pH value of 2 to 5, wherein the acidic conditions are achieved by adding acetic acid, citric acid or dilute sulfuric acid.
[0016] As a further embodiment of the present invention, in step S2, the alkaline metal oxide precursor is a mixture of K2CO3 and Ca(OH)2 in a mass ratio of 1:0.5 to 1:2.
[0017] As a further embodiment of the present invention, in step S3, the reaction temperature of the in-situ catalytic gasification reaction is 750-850°C, the molar ratio of oxygen molecules to carbon atoms in the catalytic carbon material in the oxygen-water vapor mixed gasifying agent is 0.2-0.4, the molar ratio of water molecules to carbon atoms in the catalytic carbon material is 0.6-1.2, the oxygen volume fraction in the oxygen-water vapor mixed gasifying agent is 25-50%, and the gasifying agent is preheated to 400-600°C before entering the gasification reactor.
[0018] As a further embodiment of the present invention, in step S4, the in-situ reforming temperature is 850–950°C, the pipe length between the gasification reactor and the integral honeycomb ceramic catalytic reforming reactor does not exceed 2 meters, and the inner wall of the pipe is coated with a silicon carbide-based anti-coking coating. The channel density of the integral honeycomb ceramic catalytic reforming reactor is 200–600 cpsi, and the catalyst coating is a NiCeO2ZrO2 / Al2O3 composite coating.
[0019] As a further embodiment of the present invention, in step S5, the high-temperature filter is a metal sintered filter with a filtration accuracy of 0.5 to 5 μm and an operating temperature of 300 to 500 °C.
[0020] As a further aspect of the present invention, in step S6, the proportion of purified gas in the recirculated gasification reactor is 0.1 to 0.3.
[0021] The beneficial effects of this invention are that hydrothermal carbonization pretreatment reduces the formation of tar precursors and regulates the oxygen / carbon atomic ratio of the feedstock. Combined with the in-situ pyrolysis of tar by alkaline metal oxide-modified catalytic carbon materials during the gasification stage and the efficient reforming of residual tar by the integral honeycomb ceramic catalytic reforming reactor, the tar content in the product gas is significantly reduced. The use of an oxygen-water vapor mixed gasifier avoids nitrogen dilution. Combined with the regulation of the oxygen / carbon ratio of the feedstock by hydrothermal carbonization and the enhancement of the water-gas shift reaction by the honeycomb ceramic reforming reactor, the H2 / CO molar ratio of the syngas is kept within a suitable range, allowing for direct... It is used in chemical processes such as methanol synthesis; by recycling part of the purified gas back to the gasification reactor, the carbon conversion rate is significantly improved by utilizing the CO2 and H2O in the recycled gas to react with residual carbon; the gasification reactor and the reforming reactor are directly connected by a short pipe and the inner wall is coated with an anti-coking coating, eliminating the energy loss link of cooling to remove tar and then heating to reform in the traditional process; the integral honeycomb ceramic structure combined with the composite coating effectively inhibits carbon deposition and extends the catalyst life; at the same time, the hydrothermal carbonization pretreatment can process biomass raw materials with high water content without pre-drying, which significantly reduces the energy consumption of raw material pretreatment. Attached Figure Description
[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 A flowchart of a biomass gasification fuel. Detailed Implementation
[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] A biomass gasification fuel, the gasification fuel being prepared by a method comprising the following steps: S1, the biomass raw material is subjected to hydrothermal carbonization to obtain a hydrothermal carbon intermediate.
[0026] Preferably, the hydrothermal carbonization treatment is carried out in a sealed environment at 180–260°C for 0.5–4 hours. The ratio of oxygen atoms to carbon atoms in the hydrothermal carbon intermediate is 0.20–0.40, and the specific surface area of the hydrothermal carbon intermediate is 100–350 m². 2 / g.
[0027] Preferably, the hydrothermal carbonization treatment is carried out under acidic conditions with a pH value of 2 to 5, and the acidic conditions are achieved by adding acetic acid, citric acid or dilute sulfuric acid.
[0028] Specifically, corn stalks are crushed to 2-5 mm, washed to remove mud and sand, and the moisture content is controlled at 70%. The raw material is then loaded into a hydrothermal carbonization reactor, sealed, and heated to 200°C for 2 hours. The pressure inside the reactor is the saturated vapor pressure of water in a sealed environment (approximately 1.6 MPa). After the reaction, the reactor is cooled, subjected to solid-liquid separation, and dried to obtain a hydrothermal carbon intermediate. The oxygen / carbon atom ratio of this intermediate is determined to be 0.28, and its specific surface area is 180 m². 2 / g.
[0029] S2, the hydrothermal carbon intermediate is mixed with an alkaline metal oxide precursor solution and dried, and then pyrolyzed and activated at 500-700℃ in an inert atmosphere to obtain an alkaline metal oxide modified catalytic carbon material.
[0030] Preferably, the alkaline metal oxide precursor is a mixture of K2CO3 and Ca(OH)2 in a mass ratio of 1:0.5 to 1:2.
[0031] Specifically, K₂CO₃ and Ca(OH)₂ were mixed at a mass ratio of 1:1, and water was added to prepare a 10 wt% alkaline metal oxide precursor solution. The hydrothermal carbon intermediate obtained in step S1 was impregnated in the above solution at a solid-liquid ratio of 1:3 (g / mL) and stirred at 80°C for 4 h. After filtration, it was dried at 110°C for 12 h, and then pyrolyzed and activated at 600°C under a nitrogen atmosphere for 1 h to obtain an alkaline metal oxide-modified catalytic carbon material. The total loading of alkaline metal oxides in the catalytic carbon material was determined to be 8.5 wt%.
[0032] S3, the catalytic carbon material is fed into the gasification reactor, and an in-situ catalytic gasification reaction is carried out in an atmosphere of oxygen-water vapor mixed gasifying agent to obtain crude syngas.
[0033] Preferably, the reaction temperature of the in-situ catalytic gasification reaction is 750–850°C, the molar ratio of oxygen molecules to carbon atoms in the catalytic carbon material in the oxygen-water vapor mixed gasifying agent is 0.2–0.4, the molar ratio of water molecules to carbon atoms in the catalytic carbon material is 0.6–1.2, the oxygen volume fraction in the oxygen-water vapor mixed gasifying agent is 25–50%, and the gasifying agent is preheated to 400–600°C before entering the gasification reactor.
[0034] Specifically, the catalytic carbon material obtained in step S2 is continuously fed into a fluidized bed gasification reactor. The gasifying agent is a mixture of oxygen and water vapor, with an oxygen volume fraction of 35%. The molar ratio of oxygen molecules to carbon atoms in the catalytic carbon material is controlled at 0.3, and the molar ratio of water molecules to carbon atoms in the catalytic carbon material is controlled at 0.9. The gasifying agent is preheated to 500°C before entering the reactor. The gasification reaction temperature is 800°C, and the pressure is 0.3 MPa, yielding crude syngas.
[0035] S4. The crude syngas is fed into an integrated honeycomb ceramic catalytic reforming reactor for in-situ reforming to obtain reformed gas.
[0036] Preferably, the in-situ reforming temperature is 850–950°C, the pipe length between the gasification reactor and the integral honeycomb ceramic catalytic reforming reactor does not exceed 2 meters, and the inner wall of the pipe is coated with a silicon carbide-based anti-coking coating. The channel density of the integral honeycomb ceramic catalytic reforming reactor is 200–600 cpsi, and the catalyst coating is a NiCeO2ZrO2 / Al2O3 composite coating.
[0037] Specifically, the crude syngas from the gasification reactor outlet is directly introduced into an integral honeycomb ceramic catalytic reforming reactor through a 1.5-meter-long pipe with an inner wall coated with a silicon carbide-based anti-coking coating. The reforming reactor has a channel density of 400 cpsi, and the catalyst coating is a NiCeO2ZrO2 / Al2O3 composite coating, with a Ni loading of 12 wt%, a CeO2 content of 6 wt%, a ZrO2 content of 5 wt%, and a coating porosity of 45%. The reforming temperature is 900℃, and the radial temperature gradient of the catalyst bed is controlled within 12℃ to obtain reformed gas.
[0038] S5, the reformed gas is sequentially purified by passing it through a high-temperature filter and a desulfurization adsorber to obtain purified gas.
[0039] Preferably, the high-temperature filter is a sintered metal filter with a filtration accuracy of 0.5 to 5 μm and an operating temperature of 300 to 500 °C.
[0040] Specifically, the reformed gas is purified sequentially through a sintered metal filter and a desulfurization adsorber. The sintered metal filter has a filtration accuracy of 2 μm and an operating temperature of 400°C. The desulfurization adsorber contains a ZnO desulfurization bed and an activated carbon adsorption bed, which are used to remove sulfur-containing compounds and residual organic impurities, respectively, to obtain purified gas.
[0041] S6 recycles part of the purified gas back into the gasification reactor, and outputs the remaining purified gas as biomass gasification fuel.
[0042] Preferably, the proportion of purified gas in the recirculating gasification reactor is 0.1 to 0.3.
[0043] Specifically, a portion of the purified gas obtained in step S5 is recycled back to the gasification reactor in step S3 at a recycling ratio of 0.2, and the remaining portion is output as biomass gasification fuel.
[0044] The purified gas circulating back to the gasification reactor contains CO2 and H2O, which can react with incompletely gasified residual carbon to generate CO and H2, thereby improving the carbon conversion rate. Simultaneously, the circulating gas can serve as a temperature control medium, preventing localized overheating and slagging in the gasifier, improving the gasification atmosphere, and adjusting the H2 / CO ratio of the syngas. A circulation ratio below 0.1 has little effect, while a ratio above 0.3 significantly increases energy consumption and dilutes the reactant concentration; in this embodiment, a ratio of 0.2 is selected.
[0045] The performance indicators of the biomass gasification fuel obtained in this embodiment were measured as follows: project numerical values Tar content <![CDATA[3.2mg / Nm 3 ]]> Dust content <![CDATA[0.8mg / Nm 3 ]]> <![CDATA[H2S content]]> 5ppm <![CDATA[NH3 content]]> 15ppm <![CDATA[H2 / CO molar ratio]]> 1.62 High calorific value (dry basis) <![CDATA[13.8MJ / Nm 3 ]]> carbon conversion rate 93.5% The above results show that the biomass gasification fuel prepared using the technical solution of this invention has advantages such as low tar content, low impurity content, suitable H2 / CO ratio, high calorific value, and high carbon conversion rate. It can be directly used for methanol synthesis, Fischer-Tropsch synthesis, or gas turbine power generation without further processing.
[0046] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.
Claims
1. A biomass gasification fuel, characterized in that, The gasified fuel is prepared by a method comprising the following steps: S1, the biomass raw material is subjected to hydrothermal carbonization to obtain a hydrothermal carbon intermediate; S2, the hydrothermal carbon intermediate is mixed with an alkaline metal oxide precursor solution and dried, and then pyrolyzed and activated at 500-700°C in an inert atmosphere to obtain an alkaline metal oxide modified catalytic carbon material. S3, the catalytic carbon material is fed into the gasification reactor and an in-situ catalytic gasification reaction is carried out in an oxygen-water vapor mixed gasification agent atmosphere to obtain crude syngas; S4, the crude syngas is passed into an integral honeycomb ceramic catalytic reforming reactor for in-situ reforming to obtain reformed gas; S5, the reformed gas is purified by passing it through a high-temperature filter and a desulfurization adsorber in sequence to obtain purified gas; S6 recycles part of the purified gas back into the gasification reactor, and outputs the remaining purified gas as biomass gasification fuel.
2. The biomass gasification fuel according to claim 1, characterized in that, In step S1, the hydrothermal carbonization treatment is carried out in a sealed environment at 180–260°C for 0.5–4 hours. The ratio of oxygen atoms to carbon atoms in the hydrothermal carbon intermediate is 0.20–0.40, and the specific surface area of the hydrothermal carbon intermediate is 100–350 m². 2 / g.
3. The biomass gasification fuel according to claim 1, characterized in that, In step S1, the hydrothermal carbonization treatment is carried out under acidic conditions with a pH value of 2 to 5, and the acidic conditions are achieved by adding acetic acid, citric acid or dilute sulfuric acid.
4. The biomass gasification fuel according to claim 1, characterized in that, In step S2, the alkaline metal oxide precursor is a mixture of K2CO3 and Ca(OH)2 in a mass ratio of 1:0.5 to 1:
2.
5. A biomass gasification fuel according to claim 1, characterized in that, In step S3, the reaction temperature of the in-situ catalytic gasification reaction is 750–850°C, the molar ratio of oxygen molecules to carbon atoms in the catalytic carbon material in the oxygen-water vapor mixed gasifying agent is 0.2–0.4, the molar ratio of water molecules to carbon atoms in the catalytic carbon material is 0.6–1.2, the oxygen volume fraction in the oxygen-water vapor mixed gasifying agent is 25–50%, and the gasifying agent is preheated to 400–600°C before entering the gasification reactor.
6. A biomass gasification fuel according to claim 1, characterized in that, In step S4, the in-situ reforming temperature is 850–950°C, the pipe length between the gasification reactor and the integral honeycomb ceramic catalytic reforming reactor does not exceed 2 meters, and the inner wall of the pipe is coated with a silicon carbide-based anti-coking coating. The channel density of the integral honeycomb ceramic catalytic reforming reactor is 200–600 cpsi, and the catalyst coating is a NiCeO2ZrO2 / Al2O3 composite coating.
7. A biomass gasification fuel according to claim 1, characterized in that, In step S5, the high-temperature filter is a sintered metal filter with a filtration accuracy of 0.5–5 μm and an operating temperature of 300–500 °C.
8. A biomass gasification fuel according to claim 1, characterized in that, In step S6, the proportion of purified gas in the recirculated gasification reactor is 0.1 to 0.3.