A method for decarbonization and hydrogen production through complementary gasification of biomass and coal

Abstract

This disclosure provides a method and system for decarbonization and hydrogen production through complementary gasification of biomass and coal. In this method, biomass is dried to produce dry biomass, a portion of which enters a burner, while the other portion is combined with pretreated coal to form pyrolysis fuel, which enters a pyrolysis furnace. The dry biomass and hot air are burned in the burner to generate heat and a first flue gas. This heat and the first flue gas are used to heat a gasifier, gasifying coke from the pyrolysis furnace to generate syngas. After the first flue gas heats the gasifier, a second flue gas is discharged, which heats the pyrolysis furnace to pyrolyze the pyrolysis fuel, generating coke and pyrolysis gas. The coke is fed back to the gasifier. The syngas and pyrolysis gas form a first mixed gas, which undergoes tar separation to remove tar, generating a pure mixed gas. The pure mixed gas undergoes a water-gas shift reaction and carbon capture to obtain high-purity hydrogen. This invention achieves complementary carbon and hydrogen components between coal and biomass, increases the yield of gaseous products, and effectively reduces overall carbon emissions.

Description

Technical Field

[0001] This invention relates to the field of energy and power technology, specifically to a method and system for decarbonization and hydrogen production through complementary gasification of biomass and coal. Background Technology

[0002] As my country's economic development level continues to improve, its energy consumption is also rising. In recent years, my country's energy consumption structure has shown two main characteristics: first, the proportion of fossil fuels has decreased, but it still dominates the overall energy consumption structure; second, the proportion of new energy sources (such as wind power and photovoltaics) has increased. Furthermore, coal, as the main fossil fuel consumer, also contributes significantly to carbon dioxide emissions. my country is rich in biomass resources, mainly including agricultural and forestry waste. The rational utilization of these abundant biomass resources can not only reduce carbon dioxide emissions but also adjust and optimize my country's energy structure, providing a strong guarantee for sustainable energy development.

[0003] Pyrolysis is a thermochemical process that decomposes fuels such as coal and biomass into gaseous, liquid, and solid products at high temperatures. Typically, pyrolysis occurs in the absence of oxygen or under an inert gas atmosphere, with temperatures ranging from several hundred to several thousand degrees Celsius. The properties of the pyrolysis products are mainly influenced by factors such as temperature, reaction time, type of raw materials, and reactor type.

[0004] Gasification is a process that converts carbon-based fuels into syngas at high temperatures and in a gasifying agent atmosphere. The gasification process typically takes place under high-temperature conditions, usually ranging from 600 to 1500°C, and the gasifying agent is typically oxygen, water vapor, and carbon dioxide. Syngas mainly consists of carbon monoxide, hydrogen, carbon dioxide, and methane, the proportions of which depend on the fuel and reaction conditions. Traditional gasification technologies often use partial combustion of syngas for heating or externally supplied coal combustion for heating the gasification process. These heating methods result in significant carbon dioxide emissions.

[0005] Currently, the main methods of hydrogen production in my country are divided into three categories: hydrogen production from fossil fuels, hydrogen produced as a byproduct of industry, and hydrogen production through water electrolysis. Among these, hydrogen production from fossil fuels relies on abundant resources and mature technology, resulting in large-scale production. Hydrogen production from industrial byproducts is the next largest method, while hydrogen production through water electrolysis is smaller in scale due to higher costs and a weaker technological foundation. Furthermore, hydrogen production from fossil fuels also suffers from serious pollution problems.

[0006] It is evident that existing gasification and hydrogen production methods all suffer from severe pollution problems. Achieving efficient and clean utilization of coal and reducing carbon dioxide emissions from fossil fuel-based hydrogen production are urgent issues that need to be addressed. Summary of the Invention

[0007] In view of this, the present invention provides a method and system for decarbonization and hydrogen production through complementary gasification of biomass and coal, which realizes the complementarity of carbon and hydrogen components of coal and biomass, increases the yield of gaseous products, and effectively reduces the overall carbon emissions.

[0008] To solve the above-mentioned technical problems, the present invention is implemented as follows.

[0009] A method for decarbonization and hydrogen production through complementary gasification of biomass and coal includes:

[0010] Step 1: Biomass is dried to produce dry biomass. Part of the dry biomass enters the burner, and the other part is combined with pretreated coal to form pyrolysis fuel, which enters the pyrolysis furnace. The proportion of biomass in the pyrolysis fuel is greater than or equal to 0.

[0011] Step 2: Dry biomass and hot air are burned in a burner to generate heat and first flue gas;

[0012] Step 3: Use the heat and the first flue gas to heat the gasifier, gasify the coke from the pyrolysis furnace to generate syngas; the flue gas discharged after the first flue gas heats the gasifier is called the second flue gas.

[0013] Step 4: Use the second flue gas to heat the pyrolysis furnace, pyrolyze the pyrolysis fuel to generate coke and pyrolysis gas, and feed the coke back to the gasifier.

[0014] Step 5: Syngas and pyrolysis gas form the first mixed gas, and tar is removed by tar separation to generate a pure mixed gas;

[0015] Step 6: The pure mixed gas enters the shift reactor and undergoes a water-gas shift reaction to generate converted gas;

[0016] Step 7: Use a carbon capture unit to separate carbon dioxide from the conversion gas to obtain hydrogen with higher purity.

[0017] Preferably, the second flue gas in step 4 is the flue gas discharged after the pyrolysis furnace is heated, which is called the third flue gas; the third flue gas is used to heat the air preheater to preheat the air and obtain hot air to enter the burner.

[0018] Preferably, the first mixed gas generated in step 5 is used in two stages before tar separation.

[0019] The two-stage cascade utilization includes:

[0020] The first mixed gas enters the heat exchanger to preheat the gasifying agent, and the heated gasifying agent enters the gasifier to provide a high-temperature gasifying agent for the gasification reaction in the gasifier; the first mixed gas forms a second mixed gas after heat exchange.

[0021] The second mixed gas enters the dryer to dry the biomass, generating the dried biomass required in step 1; the second mixed gas is then heat-exchanged a second time to form the third mixed gas.

[0022] The third mixture then enters the tar separation unit for tar separation;

[0023] The temperatures of the first, second, and third mixtures decrease sequentially.

[0024] Preferably, the biomass drying temperature in step 1 is in the range of 100-150℃; the operating temperature range of the gasification furnace in step 3 is 900-1500℃; the operating temperature range of the pyrolysis furnace in step 4 is 200-1000℃; and the temperature range of the water-gas shift reaction in step 6 is 200-500℃.

[0025] Preferably, the gasifying agent introduced into the gasifier in step 3 is water vapor, oxygen, or carbon dioxide.

[0026] Preferably, the tar separation method in step 5 is either water washing or adsorption.

[0027] Preferably, the carbon dioxide capture method of the carbon capture unit in step 7 is chemical absorption, physical absorption, or adsorption.

[0028] This invention also provides a decarbonization and hydrogen production system for biomass and coal complementary gasification, the system comprising:

[0029] An air preheater is used to heat air to generate hot air, which is then supplied to the burner.

[0030] A dryer is used to heat biomass to generate dry biomass, which is then supplied to a burner as combustion fuel. A portion of the dry biomass is also separated from the pyrolysis fuel and supplied to the pyrolysis furnace as pyrolysis fuel, according to the required biomass ratio for the pyrolysis furnace fuel; the biomass ratio in the pyrolysis fuel is greater than or equal to 0.

[0031] The burner is used to burn dry biomass and hot air to generate heat and first flue gas to heat the gasifier.

[0032] A gasifier is used to heat coke and gasifying agent from a pyrolysis furnace using the heat and the first flue gas, so that the coke is gasified to generate syngas; the flue gas discharged after the first flue gas is used to heat the gasifier is called the second flue gas.

[0033] The coal pretreatment unit crushes coal to produce coal for pyrolysis and provides it to the pyrolysis furnace; the coal and the partially dried biomass from the dryer are blended to form pyrolysis fuel.

[0034] A pyrolysis furnace is used to pyrolyze the pyrolysis fuel using the heat of the second flue gas to produce pyrolysis gas and coke; the coke is fed back to the gasifier.

[0035] The mixed gas heat utilization component is used to collect the mixed gas composed of syngas and pyrolysis gas, and output it to the tar separation unit after heat exchange;

[0036] Tar separation unit is used to separate tar from gas mixture to produce pure gas mixture;

[0037] A water vapor converter converts carbon monoxide in a pure gas mixture into carbon dioxide and hydrogen through a water vapor conversion reaction, resulting in a converted gas mainly composed of carbon dioxide and hydrogen.

[0038] The carbon capture unit is used to capture carbon dioxide from the conversion gas and generate hydrogen gas with high purity.

[0039] Preferably, the second flue gas is the flue gas discharged after heating the pyrolysis furnace, which is called the third flue gas; the third flue gas is heated by the air preheater and used to preheat the air.

[0040] Preferably, the mixed gas heat utilization component uses a heat exchanger to exchange heat with the mixed gas composed of syngas and pyrolysis gas to preheat the gasifying agent, forming a high-temperature gasifying agent, which is then supplied to the gasifier.

[0041] After heat exchange, the mixed gas forms a second mixed gas, which enters the dryer to provide heat for biomass heating; after heat exchange in the dryer, the second mixed gas forms a third mixed gas, which enters the tar separation device for tar separation; the temperatures of the mixed gas, the second mixed gas, and the third mixed gas decrease in that order.

[0042] Beneficial effects:

[0043] (1) The coke produced by the pyrolysis furnace of the present invention is provided to the gasification furnace, and the heat and flue gas generated by the gasification furnace are provided to the pyrolysis furnace. Compared with coal, biomass has a large difference in fuel characteristics. The hydrogen and oxygen content in biomass is higher than that in coal. The addition of biomass can provide more hydrogen and oxygen for pyrolysis. The co-pyrolysis of biomass and coal realizes the complementarity of carbon and hydrogen components between coal and biomass, and increases the yield of gaseous products.

[0044] (2) Using the heat generated by biomass combustion and the high-temperature flue gas to heat the pyrolysis and gasification process can effectively reduce carbon emissions during the heating process.

[0045] (3) In a preferred embodiment, the biomass is rich in alkali metal elements and the pyrolysis fuel contains biomass, which can reduce the activation energy of the pyrolysis and gasification reaction and increase the reaction rate.

[0046] (4) The carbon capture unit can effectively capture carbon dioxide in the converted gas, reducing overall carbon emissions;

[0047] (5) The high-temperature flue gas generated from biomass combustion can successively heat the gasifier, pyrolysis furnace and air preheater. In addition, the heat from the pyrolysis gas and syngas is also used for heating the gasifying agent and drying the biomass. The utilization of this heat realizes the cascade utilization of heat.

[0048] Therefore, this invention has good social benefits and industrial application scenarios. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the decarbonization and hydrogen production method of biomass and coal complementary gasification in an embodiment of the present invention.

[0050] Figure 2 This is a flowchart illustrating the decarbonization and hydrogen production system of the biomass and coal complementary gasification system in an embodiment of the present invention.

[0051] In the above appendix Figure 2 The components and their corresponding markings are as follows: 1-Air preheater; 2-Coal pretreatment unit; 3-Pyrolysis furnace; 4-Gasifier; 5-Burner; 6-Heat exchanger; 7-Dryer; 8-Tar separation device; 9-Water-steam conversion reactor; 10-Carbon capture unit; 11-Air; 12-Hot air; 13-Coal; 14-Coal used for pyrolysis; 15-Third flue gas; 16-Low temperature flue gas; 17-Pyrolysis gas; 18-Coke; 19-... - Second flue gas; 20- Syngas; 21- Gasifying agent; 22- High-temperature gasifying agent; 23- Dried biomass; 26- Partially dried biomass, supplied to the pyrolysis furnace; 24- First flue gas; 25- Heat; 27- Medium-temperature mixed gas (second mixed gas); 28- Low-temperature mixed gas (third mixed gas); 29- Biomass; 30- Tar; 31- Pure mixed gas; 32- Converted gas; 33- Carbon dioxide; 34- High-purity hydrogen. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0053] This invention provides a decarbonization and hydrogen production scheme for biomass and coal complementary gasification, the core features of which are as follows:

[0054] Biomass and coal have different fuel characteristics. Generally, biomass has a higher hydrogen-to-carbon ratio and a higher alkali metal content than coal. This invention achieves carbon-hydrogen composition complementarity between coal and biomass through complementary gasification, making it easier to obtain higher gaseous product yields. The higher content of alkali metals such as K and Na in biomass compared to coal will have a certain catalytic effect on the pyrolysis and gasification processes, reducing the activation energy of the pyrolysis and gasification reactions and increasing the reaction rate.

[0055] Secondly, this invention uses external combustion of biomass to heat the gasifier and utilizes the high-temperature flue gas generated from biomass combustion to heat the pyrolysis furnace. Since biomass is a carbon-neutral fuel, the main advantage of this method is that it achieves zero carbon dioxide emissions during the heating process, thus improving the energy quality matching.

[0056] Moreover, compared with traditional fossil fuel-based hydrogen production, this invention also captures the carbon dioxide produced during the hydrogen production process, reducing carbon dioxide emissions.

[0057] Furthermore, the high-temperature flue gas generated by biomass combustion in this invention can sequentially heat the gasifier, pyrolysis furnace, and air preheater, while the medium-temperature mixed gas can be used to dry biomass, thus realizing the cascade utilization of heat.

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings.

[0059] Figure 1 A flowchart of a preferred embodiment of the decarbonization and hydrogen production method of biomass and coal complementary gasification according to the present invention is shown in the figure. The method includes the following steps:

[0060] Step S1: Biomass enters the dryer to generate dried biomass. Part of the dried biomass enters the burner, and the other part is combined with pretreated coal to form pyrolysis fuel, which then enters the pyrolysis furnace.

[0061] This process can be considered a fuel pretreatment process, which can dry biomass. The types of biomass and coal are not limited.

[0062] Preferably, the heat required for the drying process of biomass comes from the intermediate-temperature mixed gas generated by heat exchange between pyrolysis gas and syngas, namely the second mixed gas.

[0063] Step S2: Dry biomass and hot air are burned to generate heat and first flue gas.

[0064] The process uses the dry biomass produced in step S1 and the hot air produced in step S5 to burn in a burner to generate heat and first flue gas.

[0065] Step S3: Heat is used to heat the gasifier with heat and the first flue gas to gasify the coke into syngas.

[0066] This process uses the heat generated by the burner in step S2 and the first flue gas to heat the gasifier, heating the coke and high-temperature gasifying agent to generate syngas. The main components of the syngas are hydrogen, carbon monoxide, carbon dioxide, and methane. The coke used in the gasifier comes from the pyrolysis furnace. The gasifier can fully utilize the heat generated by biomass combustion and the heat released by the first flue gas to gasify the coke into syngas.

[0067] Step S4: Use the second flue gas to heat the pyrolysis furnace, and pyrolyze the fuel to produce coke and pyrolysis gas.

[0068] The first flue gas in step S3, after being used to heat the gasifier, still retains a certain amount of heat and is referred to as the second flue gas. This second flue gas provides the necessary heat to the pyrolysis furnace. In practice, the second flue gas can also be released into the environment. However, this embodiment utilizes the second flue gas to heat both the gasifier and the pyrolysis furnace, making full use of the heat generated by the system.

[0069] The pyrolysis fuel in this step can be coal, biomass, or a mixture of coal and biomass. The blending ratio of biomass and coal is not limited, and the biomass ratio can be 0.

[0070] Step S5: Use the third flue gas to heat the air preheater to preheat the air, and the hot air enters the burner.

[0071] The second flue gas in step S4, after being heated by the pyrolysis furnace, still retains a certain amount of heat and is called the third flue gas. The third flue gas provides the required heat to the air preheater.

[0072] The first flue gas provides heat to the gasifier, pyrolysis furnace, and air preheater in sequence, following the principle of temperature gradient utilization. The temperatures of the first, second, and third flue gases decrease sequentially.

[0073] Step S6: The syngas and pyrolysis gas combine to form a high-temperature mixed gas, which enters a heat exchanger to preheat the gasifying agent. The heated high-temperature gasifying agent then enters the gasification furnace. The heat from the high-temperature gasifying agent is utilized by the heat exchanger to obtain a medium-temperature mixed gas.

[0074] The process utilizes the heat from the pyrolysis gas generated in step S4 and the syngas generated in step S3 to heat the gasifying agent, thereby generating a high-temperature gasifying agent.

[0075] Step S7: The medium-temperature mixed gas enters the dryer to dry the biomass. After heat exchange, a low-temperature mixed gas, namely the third mixed gas, is obtained. The low-temperature mixed gas enters the tar separation device to remove tar and generate a pure mixed gas.

[0076] The process utilizes the medium-temperature mixed gas generated in step S6 to provide heat for the biomass drying process, and removes the tar in the low-temperature mixed gas through a tar separation device to generate a pure mixed gas.

[0077] In this step, the tar removal method can be either water washing or adsorption.

[0078] Step S8: The pure mixed gas enters the shift reactor and undergoes a water-gas shift reaction to generate shift gas.

[0079] This process utilizes a water-vapor shift reaction to convert carbon monoxide in the pure mixed gas in step S7 into carbon dioxide and hydrogen, producing a shifted gas mainly composed of carbon dioxide and hydrogen.

[0080] Step S9: Separate carbon dioxide from the conversion gas through the carbon capture unit to obtain hydrogen gas with higher purity.

[0081] The converted gas generated in step S8 is passed into a carbon capture unit to separate carbon dioxide and pure hydrogen. The separated carbon dioxide is stored. Here, the carbon dioxide capture method can be chemical absorption, physical absorption (e.g., Selexol technology), adsorption, etc.

[0082] The above process can yield hydrogen and carbon dioxide with relatively high purity.

[0083] In a preferred embodiment, the biomass drying temperature in step S1 is in the range of 100-150°C.

[0084] In step S3, the operating temperature range of the gasifier is 900-1500℃.

[0085] In step S4, the operating temperature range of the pyrolysis furnace is 200-1000℃.

[0086] In step S6, the vaporizing agent can be water vapor, oxygen, or carbon dioxide.

[0087] The temperature range for the water-vapor shift reaction in step S8 is 200-500℃.

[0088] As can be seen, the low-carbon hydrogen production method proposed in this invention achieves carbon-hydrogen component complementarity between coal and biomass, increasing the yield of gaseous products. Biomass, rich in alkali metals, can lower the activation energy of pyrolysis and gasification reactions and increase the reaction rate. Using external combustion of biomass to heat the gasifier and utilizing the high-temperature flue gas generated from biomass combustion to heat the pyrolysis furnace reduces carbon dioxide emissions and improves energy quality matching compared to traditional heating methods. Compared to traditional fossil fuel-based hydrogen production, this invention captures the carbon dioxide generated during hydrogen production, reducing carbon dioxide emissions. Furthermore, the high-temperature flue gas generated from biomass combustion in this invention can sequentially heat the gasifier, pyrolysis furnace, and air preheater, while the medium-temperature mixed gas can be used to dry biomass, achieving cascade utilization of heat.

[0089] To better illustrate the method proposed in this invention, this invention also provides a decarbonization and hydrogen production system for biomass and coal complementary gasification. For example... Figure 2 As shown, the system includes an air preheater 1, a coal pretreatment unit 2, a pyrolysis furnace 3, a gasifier 4, a burner 5, a heat exchanger 6, a dryer 7, a tar separation device 8, a water-steam conversion reactor 9, and a carbon capture unit 10. Among them:

[0090] Air preheater 1 can perform the above step S5, heating air 11 to generate hot air 12, which is then supplied to burner 5. In a preferred embodiment, the heat from the third flue gas 15 discharged from pyrolysis furnace 3 can be used to preheat air 11, generating high-temperature air 12, while the resulting low-temperature flue gas 16 is discharged into the environment.

[0091] The coal pretreatment unit 2 can perform the above step S1, crushing coal 13 into coal 14 for pyrolysis and supplying it to the pyrolysis furnace 3. The coal 14 and dried biomass 26 from the dryer are blended to form pyrolysis fuel.

[0092] The pyrolysis furnace 3 can perform the above step S4, using the heat from the second flue gas 19 discharged from the gasifier 4 to pyrolyze the coal 14 and dry biomass 26, generating pyrolysis gas 17 and coke 18. The coke 18 is fed back to the gasifier 4.

[0093] Gasifier 4 can perform the above step S3, and is used to heat coke 18 and high-temperature gasifying agent 22 by using heat 25 and the heat of first flue gas 24, so that coke is gasified to generate high-temperature syngas 20.

[0094] Burner 5 performs step S2 above, burning dry biomass 23 and hot air 12 to generate heat 25 and first flue gas 24. The first flue gas 24 sequentially provides heat to the gasifier, pyrolysis furnace, and air preheater, following the principle of temperature gradient utilization. The gasifier discharges second flue gas 19, and the pyrolysis furnace discharges third flue gas 15; the temperatures of the first flue gas 24, second flue gas 19, and third flue gas 15 decrease sequentially.

[0095] Heat exchanger 6 can realize the above step S6. As a mixed gas heat utilization component, it is used to heat the gasifying agent 21 by utilizing the heat of the mixed gas formed by pyrolysis gas 17 and synthesis gas 20 to generate high-temperature gasifying agent 22.

[0096] Dryer 7 can perform the above step S1, drying biomass 29 to generate dried biomass 23, which is then supplied to burner 5; a portion of dried biomass 26 is extracted from the dried biomass 23 and supplied to pyrolysis furnace 3. The amount of dried biomass 26 can be determined according to the blending ratio of biomass in the pyrolysis fuel.

[0097] Preferably, the dryer 7 can use the heat from the medium-temperature mixed gas 27 (i.e., the second mixed gas) generated by the heat exchanger to dry the biomass. After heat exchange in the dryer 7, the low-temperature mixed gas 28 (i.e., the third mixed gas) enters the tar separation unit 8.

[0098] Tar separation device 8 is used to separate tar 30 from low-temperature mixed gas 28 to generate pure mixed gas 31.

[0099] The water-steam conversion reactor 9 can achieve the above step S8, converting carbon monoxide in the pure mixed gas 31 into carbon dioxide and hydrogen through the water-steam conversion reaction, and obtaining the conversion gas 32 mainly composed of carbon dioxide and hydrogen.

[0100] The carbon capture unit 10 can perform the above step S9 to capture carbon dioxide 33 in the conversion gas 32 and produce hydrogen 34 with high purity.

[0101] Among them, the dryer 7 can be an airflow dryer, and the pyrolysis furnace 3 and the gasification furnace 4 can refer to existing processes.

[0102] Example

[0103] To further illustrate the feasibility of the present invention, a typical operating condition was selected, and simulation calculations were performed on the decarbonization and hydrogen production system. In the selected operating condition, coal and biomass were used as fuels in the complementary gasification process, with a biomass mass blending ratio of 0.25 in the mixed fuel. Biomass was used as fuel for the burner. Table 1 shows the basic operating parameters of the embodiment.

[0104] To demonstrate that the present invention can produce hydrogen with high purity, Table 2 shows the main components of the pyrolysis gas in the simulation calculation results, Table 3 shows the main components of the synthesis gas in the simulation calculation results, and Table 4 shows the main components of the gas produced in the simulation calculation results.

[0105] Table 5 presents the system energy analysis results of the embodiment. From the perspective of energy input, in the embodiment, the energy of coal used for pyrolysis accounts for 58.95% of the total input energy, the energy of biomass used for pyrolysis accounts for 11.92% of the total input energy, the energy of biomass used for external combustion heating accounts for 25.74% of the total input energy, the energy consumption for carbon capture accounts for 2.25% of the total input energy, and the energy consumption for the compressor accounts for 1.14% of the total input energy. From the perspective of energy efficiency, the cold gas efficiency of the embodiment is 87.97%, and the hydrogen production efficiency of the embodiment is 80.34%, which is higher than the hydrogen production efficiency (50-60%) of the traditional coal-to-hydrogen system.

[0106] Table 1 Basic parameters of the embodiment

[0107]

[0108]

[0109] Table 2 Main components of pyrolysis gas

[0110] Main ingredients Volume fraction <![CDATA[H2]]> 33.40％ CO 28.12％ <![CDATA[CO2]]> 19.70％ <![CDATA[CH4]]> 14.28％ <![CDATA[C2H4]]> 1.53％ <![CDATA[C2H6]]> 0.42％ tar 2.55％ total 100.00％

[0111] Table 3. Main components of syngas

[0112] Main ingredients Volume fraction <![CDATA[N2]]> 0.32％ <![CDATA[H2]]> 51.81％ CO 40.31％ <![CDATA[CO2]]> 1.75％ <![CDATA[CH4]]> 1.13％ <![CDATA[H2O]]> 4.59％ <![CDATA[H2S]]> 0.09％ total 100.00％

[0113] Table 4 Main components of the produced gas

[0114] Main ingredients Volume fraction <![CDATA[H2]]> 90.96％ <![CDATA[N2]]> 0.28％ CO 1.79％ <![CDATA[CO2]]> 2.25％ <![CDATA[CH4]]> 4.27％ <![CDATA[C2H4]]> 0.35％ <![CDATA[C2H6]]> 0.10％ total 100.00％

[0115] Table 5 Energy analysis results of the embodiments

[0116]

[0117] The specific embodiments described above only illustrate the design principles of the present invention. The shapes and names of the components in this description may differ and are not limited. Therefore, those skilled in the art can modify or make equivalent substitutions to the technical solutions described in the foregoing embodiments; and these modifications and substitutions do not depart from the inventive spirit and technical solutions of the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A method for decarbonization and hydrogen production through complementary gasification of biomass and coal, characterized in that, include: Step 1: Biomass is dried to produce dry biomass. Part of the dry biomass enters the burner, and the other part is combined with pretreated coal to form pyrolysis fuel, which enters the pyrolysis furnace; the proportion of biomass in the pyrolysis fuel is greater than 0. Step 2: Dry biomass and hot air are burned in a burner to generate heat and first flue gas; Step 3: Use the heat and the first flue gas to heat the gasifier, and gasify the coke from the pyrolysis furnace to generate syngas; the flue gas discharged after the first flue gas is used to heat the gasifier is called the second flue gas; Step 4: Use the second flue gas to heat the pyrolysis furnace, pyrolyze the pyrolysis fuel to generate coke and pyrolysis gas, and feed the coke back to the gasifier; Step 5: The syngas from the gasifier and the pyrolysis gas form a first mixed gas, and the tar is removed by tar separation to generate a pure mixed gas; Step 6: The pure mixed gas enters the shift reactor to undergo a water-gas shift reaction to generate converted gas; Step 7: Use a carbon capture unit to separate carbon dioxide from the converted gas to obtain purified hydrogen.

2. The method as described in claim 1, characterized in that, The second flue gas in step 4 is the flue gas discharged after heating the pyrolysis furnace, which is called the third flue gas. The third flue gas is used to heat the air preheater to preheat the air and obtain hot air to enter the burner.

3. The method as described in claim 1, characterized in that, The first mixed gas generated in step 5 is then subjected to tar separation after being utilized in two stages. The two-stage cascade utilization includes: The first mixed gas enters a heat exchanger to preheat the gasifying agent, and the heated gasifying agent enters the gasifier to provide a high-temperature gasifying agent for the gasification reaction in the gasifier; the first mixed gas is transformed into a second mixed gas after heat exchange. The second mixed gas enters the dryer to dry the biomass, generating the dried biomass required in step 1; the second mixed gas forms the third mixed gas after a second heat exchange. The third mixed gas then enters the tar separation device for tar separation; The temperatures of the first mixture, the second mixture, and the third mixture decrease sequentially.

4. The method as described in claim 1, characterized in that, The biomass drying temperature in step 1 is in the range of 100-150℃; the operating temperature range of the gasification furnace in step 3 is 900-1500℃; the operating temperature range of the pyrolysis furnace in step 4 is 200-1000℃; and the temperature range of the water-gas shift reaction in step 6 is 200-500℃.

5. The method as described in claim 1, characterized in that, In step 3, the gasifying agent introduced into the gasifier is water vapor, oxygen, or carbon dioxide.

6. The method as described in claim 1, characterized in that, The tar separation method in step 5 is either water washing or adsorption.

7. The method as described in claim 1, characterized in that, In step 7, the carbon dioxide capture method of the carbon capture unit is chemical absorption, physical absorption, or adsorption.

8. A decarbonization and hydrogen production system for biomass and coal complementary gasification, characterized in that, The system includes: An air preheater (1) is used to heat air (11) to generate hot air (12), which is then supplied to the burner (5). The dryer (7) is used to heat biomass (29) to generate dried biomass (23), which is supplied to the burner (5) as combustion fuel. According to the required biomass ratio of the fuel in the pyrolysis furnace (3), a portion of dried biomass (26) is separated from the dried biomass (23) and supplied to the pyrolysis furnace (3) as pyrolysis fuel; the biomass ratio in the pyrolysis fuel is greater than 0. The burner (5) is used to burn the dry biomass (23) and the hot air (12) to generate heat (25) and first flue gas (24) to heat the gasifier (4); A gasifier (4) is used to heat coke (18) and gasifying agent from a pyrolysis furnace (3) using the heat (25) and the first flue gas (24), so that the coke (18) is gasified to generate syngas (20); the first flue gas is the flue gas discharged after heating the gasifier, which is called the second flue gas (19). The coal pretreatment unit (2) crushes coal (13) to generate coal (14) for pyrolysis and provides it to the pyrolysis furnace (3); the coal (14) for pyrolysis and the partially dried biomass (26) from the dryer (7) are blended to form pyrolysis fuel. The pyrolysis furnace (3) is used to pyrolyze the pyrolysis fuel using the heat of the second flue gas (19) to produce pyrolysis gas (17) and coke (18); the coke (18) is fed back to the gasifier (4). The mixed gas heat utilization component is used to collect the syngas (20) and the pyrolysis gas (17) to form a mixed gas, which is then output to the tar separation device (8) after heat exchange. Tar separation device (8) is used to separate tar (30) from the gas mixture to generate pure gas mixture (31); The water vapor converter (9) converts carbon monoxide in the pure mixed gas (31) into carbon dioxide and hydrogen through a water vapor conversion reaction, resulting in a converted gas (32) mainly composed of carbon dioxide and hydrogen. A carbon capture unit (10) is used to capture carbon dioxide (33) in the conversion gas (32) and generate purified hydrogen (34).

9. The biomass and coal complementary gasification decarbonization and hydrogen production system as described in claim 8, characterized in that, The second flue gas is the flue gas discharged after being heated by the pyrolysis furnace (3), which is called the third flue gas (15); the third flue gas (15) is used to heat the air preheater (1) and is used to preheat the air.

10. The biomass and coal complementary gasification decarbonization and hydrogen production system as described in claim 8, characterized in that, The mixed gas heat utilization component uses a heat exchanger (6) to exchange heat with the mixed gas composed of the synthesis gas (20) and the pyrolysis gas (17) to preheat the gasifying agent (21) and form a high-temperature gasifying agent (22), which is then supplied to the gasifier (4). The mixed gas is heat exchanged to form a second mixed gas (27), which enters the dryer (7) to provide heat for heating the biomass (29); the second mixed gas is heat exchanged through the dryer (7) to form a third mixed gas (28), which enters the tar separation device (8) for tar separation; the temperature of the mixed gas, the second mixed gas (27) and the third mixed gas (28) decreases.

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