Decarburization and hydrogen production method for complementary gasification of biomass and coal

Abstract

The invention provides a biomass and coal complementary gasification decarburization and hydrogen production method and system.The method comprises the steps that biomass is dried to generate dry biomass, one part of the dry biomass enters a combustor, the other part of the dry biomass and pretreated coal form pyrolysis fuel, and the pyrolysis fuel enters a pyrolysis furnace; the dry biomass and the hot air are combusted in the combustor to generate heat and first flue gas; the heat and the first flue gas are adopted to supply heat to a gasification furnace, coke from a pyrolyzing furnace is gasified, and synthesis gas is generated; second flue gas is discharged after the first flue gas supplies heat to the gasification furnace, the second flue gas supplies heat to the pyrolysis furnace, pyrolysis fuel is pyrolyzed, coke is generated, pyrolysis gas is fed back to the gasification furnace, and the coke is fed back to the pyrolysis furnace; the synthesis gas and the pyrolysis gas form a first mixed gas, tar is removed through tar separation, and a pure mixed gas is generated; and after the pure mixed gas is subjected to water vapor shift reaction and carbon capture, hydrogen with relatively high purity is obtained. According to the invention, carbon-hydrogen component complementation of coal and biomass is realized, the yield of gaseous products is increased, and the overall carbon emission is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of energy and power technology, and in particular to a decarbonization and hydrogen production method and system for complementary gasification of biomass and coal. Background Art

[0002] As my country's economic development level continues to improve, my country's energy consumption continues to increase. In recent years, my country's energy consumption structure has shown two main characteristics: first, the proportion of fossil energy has declined, but it still occupies a dominant position in my country's energy consumption structure; second, the proportion of new energy (such as wind power and photovoltaics) consumption has increased. In addition, coal, as the main body of fossil energy consumption, will also cause a large amount of carbon dioxide emissions. my country is rich in biomass resources, mainly including agricultural waste and forestry waste. Rational use of 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 the sustainable development of energy.

[0003] Pyrolysis technology is a thermochemical process that decomposes fuels such as coal and biomass into gas, liquid and solid products under high temperature. Usually, the pyrolysis process is carried out in the absence of oxygen or under an inert gas atmosphere, and the temperature range of the pyrolysis process is between several hundred degrees Celsius and several thousand degrees Celsius. The properties of the pyrolysis products are mainly affected by factors such as temperature, reaction time, type of raw materials and reactor type.

[0004] Gasification technology is a process that converts carbon-based fuels into synthesis gas under high temperature and gasifying agent atmosphere. The gasification process is usually carried out under high temperature conditions, usually in the temperature range of 600-1500°C, and the gasifying agent is usually oxygen, water vapor and carbon dioxide. The main components of synthesis gas are carbon monoxide, hydrogen, carbon dioxide and methane, etc. The proportion of these gas components depends on the fuel and reaction conditions. Traditional gasification technology usually uses part of the synthesis gas combustion to provide heat or externally supplied coal combustion to provide heat for the gasification process. These heating methods will cause large carbon dioxide emissions.

[0005] At present, the mainstream hydrogen production methods in my country are mainly divided into fossil energy hydrogen production, industrial by-product hydrogen and water electrolysis hydrogen production. Among them, fossil energy hydrogen production relies on abundant resources and mature technology level, and the scale of hydrogen production is large. The second is industrial by-product hydrogen. Water electrolysis hydrogen production has a relatively small scale due to its high cost and weak technical foundation. In addition, fossil energy hydrogen production also has serious pollution and other problems.

[0006] It can be seen that the existing gasification and hydrogen production solutions all have serious pollution problems. It is an urgent issue to achieve efficient and clean utilization of coal and reduce carbon dioxide emissions from hydrogen production from fossil energy. Summary of the invention

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

[0008] In order to solve the above technical problems, the present invention is implemented as follows.

[0009] A method for decarbonization and hydrogen production by complementary gasification of biomass and coal, comprising:

[0010] Step 1, the biomass is dried to generate dry biomass, a part of the dry biomass enters the burner, and the other part and the pretreated coal form pyrolysis fuel and enter the pyrolysis furnace; the biomass ratio 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, using the heat and the first flue gas to heat the gasifier, gasifying the coke from the pyrolysis furnace to generate synthesis gas; the flue gas discharged after the first flue gas heats the gasifier is called the second flue gas;

[0013] Step 4: using the second flue gas to heat the pyrolysis furnace, pyrolyzing the pyrolysis fuel to generate coke and pyrolysis gas, and feeding the coke back to the gasification furnace;

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

[0015] Step 6: The pure mixed gas enters the shift reactor to undergo a water vapor shift reaction to generate a conversion 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 exhausted 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 entering the burner.

[0018] Preferably, the first mixed gas produced in step 5 is utilized in two stages and then tar is separated;

[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 high-temperature gasifying agent for the gasification reaction in the gasifier; the first mixed gas is heat exchanged to form the second mixed gas;

[0021] The second mixed gas enters the dryer to dry the biomass, generating the dried biomass required for step 1; the second mixed gas undergoes a second heat exchange to form a third mixed gas;

[0022] The third mixed gas then enters the tar separation device for tar separation;

[0023] The temperatures of the first mixed gas, the second mixed gas, and the third mixed gas decrease gradually.

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

[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 a water washing method or an adsorption method.

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

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

[0029] An air preheater, used to heat air to generate hot air, which is provided to the burner;

[0030] A dryer, used for heating biomass to generate dry biomass, providing it to the burner as combustion fuel, and separating part of the dry biomass from the dry biomass according to the required biomass ratio of the pyrolysis furnace fuel and providing it to the pyrolysis furnace as pyrolysis fuel; the biomass ratio in the pyrolysis fuel is greater than or equal to 0;

[0031] A burner, used for burning the dry biomass and hot air to generate heat and first flue gas to provide heat for the gasifier;

[0032] a gasifier, for heating the coke and the gasifying agent from the pyrolysis furnace by using the heat and the first flue gas, so that the coke is gasified to generate synthesis gas; the flue gas discharged after the first flue gas provides heat to the gasifier is called the second flue gas;

[0033] The coal pretreatment unit pulverizes the coal to generate coal for pyrolysis and provides the pyrolysis furnace with the coal and the part of the dried biomass from the dryer to form pyrolysis fuel;

[0034] The pyrolysis furnace is used to utilize the heat of the second flue gas to pyrolyze the pyrolysis fuel to generate pyrolysis gas and coke; the coke is fed back to the gasification furnace;

[0035] The mixed gas heat utilization component is used to collect the synthesis gas and the pyrolysis gas to form a mixed gas, and output it to the tar separation device after heat exchange;

[0036] Tar separation device, used to separate tar from mixed gas to generate pure mixed gas;

[0037] The water vapor converter converts the carbon monoxide in the pure mixed gas into carbon dioxide and hydrogen through the water vapor conversion reaction to obtain a conversion gas mainly composed of carbon dioxide and hydrogen;

[0038] The carbon capture unit is used to capture carbon dioxide in the conversion gas and generate higher purity hydrogen.

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

[0040] Preferably, the mixed gas heat utilization component uses a heat exchanger to heat the mixed gas composed of the synthesis gas and the pyrolysis gas to preheat the gasifying agent to form a high-temperature gasifying agent, which is provided 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 temperature of the mixed gas, the second mixed gas and the third mixed gas decreases gradually.

[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 greatly different fuel properties. The content of hydrogen and oxygen in biomass is higher than that in coal. The addition of biomass can provide more hydrogen and oxygen elements for pyrolysis. The co-pyrolysis of biomass and coal realizes the complementarity of the carbon and hydrogen components of coal and biomass, thereby increasing the yield of gaseous products.

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

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

[0046] (4) The carbon capture unit can effectively capture carbon dioxide in the conversion gas and reduce overall carbon emissions;

[0047] (5) The high-temperature flue gas generated by biomass combustion can be used to heat the gasifier, pyrolysis furnace and air preheater in turn. In addition, the heat from pyrolysis gas and synthesis gas is also used to heat the gasifier and dry the biomass. The utilization of this heat realizes the cascade utilization of heat.

[0048] Therefore, the present invention has good social benefits and industrial application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of a method for decarbonization and hydrogen production by complementary gasification of biomass and coal in an embodiment of the present invention;

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

[0051] In the above-mentioned Figure 2 In the figure, the components and their corresponding marks are: 1-air preheater; 2-coal pretreatment unit; 3-pyrolysis furnace; 4-gasification furnace; 5-burner; 6-heat exchanger; 7-dryer; 8-tar separation device; 9-water gas conversion reactor; 10-carbon capture unit; 11-air; 12-hot air; 13-coal; 14-coal for pyrolysis; 15-third flue gas; 16-low temperature flue gas; 17-pyrolysis gas; 18-coke; 19 -second flue gas; 20-synthesis gas; 21-gasifying agent; 22-high-temperature gasifying agent; 23-dried biomass, 26-partially dried biomass, provided 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-conversion gas; 33-carbon dioxide; 34-higher-purity hydrogen. DETAILED DESCRIPTION

[0052] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0053] The present invention provides a decarbonization and hydrogen production scheme of biomass and coal complementary gasification, the core features of which are mainly the following:

[0054] Biomass and coal have different fuel properties. Generally, the hydrogen-to-carbon ratio of biomass is higher than that of coal, and the alkali metal content is higher than that of coal. The present invention can achieve the complementarity of carbon-hydrogen components of coal and biomass through complementary gasification, and it is easy to obtain a higher yield of gaseous products; the content of alkali metals such as K and Na in biomass is higher than that in coal, which will have a certain catalytic effect on the pyrolysis and gasification process, reduce the activation energy of the pyrolysis and gasification reactions and increase the reaction rate.

[0055] Secondly, the present invention uses biomass external combustion to heat the gasifier, and uses the high-temperature flue gas generated by 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 and improves the energy quality matching degree.

[0056] Moreover, compared with traditional hydrogen production using fossil energy, the present invention also captures the carbon dioxide generated during the hydrogen production process, thereby reducing carbon dioxide emissions.

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

[0058] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings.

[0059] Figure 1 A flow chart of a method for decarbonization and hydrogen production by complementary gasification of biomass and coal in a preferred embodiment of the present invention is shown. As shown in the figure, the method comprises the following steps:

[0060] Step S1, biomass enters the dryer to generate dry biomass, a part of the dry biomass enters the burner, and the other part and the pretreated coal form pyrolysis fuel and enter the pyrolysis furnace.

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

[0062] Preferably, the heat required for the biomass drying process comes from the medium-temperature mixed gas generated by heat exchange between pyrolysis gas and synthesis gas, that is, 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: using the heat and the first flue gas to heat the gasifier to gasify the coke to generate synthesis gas.

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

[0067] Step S4: using the second flue gas to supply heat to the pyrolysis furnace to pyrolyze the fuel to generate coke and pyrolysis gas.

[0068] After the first flue gas in step S3 heats the gasifier, it still has a certain amount of heat, which is called the second flue gas. The second flue gas provides the required heat for the pyrolysis furnace. In practice, the second flue gas can also be discharged into the environment. However, this embodiment uses the second flue gas to heat 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 to coal is not limited, and the biomass ratio can be 0.

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

[0071] After the second flue gas in step S4 provides heat to the pyrolysis furnace, it still has a certain amount of heat, which is called the third flue gas. The third flue gas provides the required heat for the air preheater.

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

[0073] Step S6: Synthesis gas and pyrolysis gas form a high-temperature mixed gas that enters a heat exchanger to preheat the gasifying agent, and the heated high-temperature gasifying agent enters a gasifier. The high-temperature gasifying agent is heat-utilized by the heat exchanger to obtain a medium-temperature mixed gas.

[0074] This process utilizes the heat of the pyrolysis gas produced in step S4 and the synthesis gas produced in step S3 to heat the gasifying agent to generate a high-temperature gasifying agent.

[0075] Step S7, the medium-temperature mixed gas enters the dryer for drying the biomass, and obtains a low-temperature mixed gas after heat exchange, namely, the third mixed gas; the low-temperature mixed gas enters the tar separation device to remove the tar and generate a pure mixed gas.

[0076] This process utilizes the medium-temperature mixed gas generated in step S6 to provide heat for the biomass drying process, and removes 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 a water washing method or an adsorption method.

[0078] Step S8: The pure mixed gas enters the shift reactor to undergo a water vapor shift reaction to generate a conversion gas.

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

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

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

[0082] The above process can produce high-purity hydrogen and carbon dioxide.

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

[0084] The operating temperature range of the gasifier in step S3 is 900-1500°C.

[0085] The operating temperature range of the pyrolysis furnace in step S4 is 200-1000°C.

[0086] The gasifying agent in step S6 may be water vapor, oxygen and carbon dioxide.

[0087] The temperature range of the water gas shift reaction in step S8 is 200-500°C.

[0088] It can be seen that in the low-carbon hydrogen production method proposed in the present invention, the carbon and hydrogen components of coal and biomass are complemented, and the output of gaseous products is improved. Biomass rich in alkali metal elements can reduce the activation energy of pyrolysis and gasification reactions and increase the reaction rate. The gasifier is heated by external combustion of biomass, and the high-temperature flue gas generated by biomass combustion is used to heat the pyrolysis furnace. Compared with the traditional heating method, it reduces carbon dioxide emissions and improves the degree of energy grade matching. Compared with traditional fossil energy hydrogen production, the present invention captures the carbon dioxide generated in the hydrogen production process and reduces carbon dioxide emissions. In addition, the high-temperature flue gas generated by biomass combustion in the present invention can be used to heat the gasifier, pyrolysis furnace and air preheater in turn, and the medium-temperature mixed gas can be used to dry biomass, realizing the cascade utilization of heat.

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

[0090] The air preheater 1 can implement the above step S5, and is used to heat the air 11 to generate hot air 12, which is provided to the burner 5. In a preferred embodiment, the heat of the third flue gas 15 discharged from the pyrolysis furnace 3 can be used to preheat the air 11 to generate high-temperature air 12, and the generated low-temperature flue gas 16 is discharged into the environment.

[0091] The coal pretreatment unit 2 can implement the above step S1, crush the coal 13 to generate coal 14 for pyrolysis, and provide it to the pyrolysis furnace 3. The coal 14 and the dry biomass 26 from the dryer are mixed to form pyrolysis fuel.

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

[0093] The gasifier 4 can implement the above step S3, and is used to heat the coke 18 and the high-temperature gasifying agent 22 using the heat 25 and the heat of the first flue gas 24, so as to gasify the coke to generate a high-temperature synthesis gas 20.

[0094] The burner 5 can implement the above step S2, and is used to burn the dry biomass 23 and the hot air 12 to generate heat 25 and the first flue gas 24. The first flue gas 24 provides heat to the gasifier, the pyrolysis furnace and the air preheater in turn, following the principle of temperature gradient utilization. The gasifier discharges the second flue gas 19, and the pyrolysis furnace discharges the third flue gas 15; the temperatures of the first flue gas 24, the second flue gas 19, and the third flue gas 15 decrease in turn.

[0095] The heat exchanger 6 can implement the above step S6 , and serves as a mixed gas heat utilization component for utilizing the heat of the mixed gas formed by the pyrolysis gas 17 and the synthesis gas 20 to heat the gasifying agent 21 to generate a high-temperature gasifying agent 22 .

[0096] The dryer 7 can implement the above step S1, and is used to dry the biomass 29 to generate the dry biomass 23, which is provided to the burner 5; and extract part of the dry biomass 26 from the dry biomass 23, which is provided to the pyrolysis furnace 3. The amount of the part of the dry biomass 26 can be determined according to the blending ratio of the biomass in the pyrolysis fuel.

[0097] Preferably, the dryer 7 can utilize the heat of 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) generated enters the tar separation unit 8.

[0098] The tar separation device 8 is used to separate the tar 30 in the low-temperature mixed gas 28 to generate a pure mixed gas 31.

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

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

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

[0102] Examples

[0103] In order to further illustrate the feasibility of the present invention, one typical operating condition was selected to simulate the decarbonization and hydrogen production system. In the selected operating condition, coal and biomass are used as fuels for the complementary gasification process, and the mass blending ratio of biomass in the mixed fuel is 0.25. Biomass is used as the fuel for the burner. Table 1 shows the basic operating parameters of the embodiment.

[0104] In order to illustrate that the present invention can produce high-purity hydrogen, Table 2 shows the main components of pyrolysis gas in the simulation calculation results, Table 3 shows the main components of synthesis gas in the simulation calculation results, and Table 4 shows the main components of the produced gas in the simulation calculation results.

[0105] Table 5 shows the system energy analysis results of the embodiment. From the perspective of energy input, the coal energy used for pyrolysis in the embodiment accounts for 58.95% of the total input energy, the biomass energy used for pyrolysis accounts for 11.92% of the total input energy, the biomass energy used for external 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 synthesis gas

[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 examples

[0116]

[0117] The above specific embodiments only describe the design principle of the present invention. The shapes and names of the components in the description may be different and are not limited. Therefore, those skilled in the art in the field of the present invention may modify or replace the technical solutions recorded in the above embodiments; and these modifications and replacements do not deviate from the creative purpose 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 by complementary gasification of biomass and coal, characterized in that: include: Step 1, the biomass is dried to generate dry biomass, a part of the dry biomass enters the burner, and the other part and the pretreated coal form pyrolysis fuel and enter the pyrolysis furnace; the biomass ratio in the pyrolysis fuel is greater than or equal to 0; Step 2: Dry biomass and hot air are burned in a burner to generate heat and first flue gas; Step 3, using the heat and the first flue gas to heat the gasifier, gasifying the coke from the pyrolysis furnace to generate synthesis gas; the flue gas discharged after the first flue gas heats the gasifier is called the second flue gas; Step 4: using the second flue gas to heat the pyrolysis furnace, pyrolyzing the pyrolysis fuel to generate coke and pyrolysis gas, and feeding the coke back to the gasification furnace; Step 5: The synthesis gas and the pyrolysis gas form a first mixed gas, and the tar is removed through tar separation to generate a pure mixed gas; Step 6: The pure mixed gas enters the shift reactor to undergo a water vapor shift reaction to generate a conversion gas; Step 7: Use a carbon capture unit to separate carbon dioxide from the conversion gas to obtain hydrogen with higher purity.

2. The method according to claim 1, characterized in that The second flue gas in step 4 is the flue gas exhausted after the pyrolysis furnace is heated, and 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 entering the burner.

3. The method according to claim 1, characterized in that The first mixed gas produced in step 5 is utilized in two stages and then tar is separated; The two-stage cascade utilization includes: The first mixed gas enters the heat exchanger to preheat the gasifying agent, and the heated gasifying agent enters the gasifier to provide high-temperature gasifying agent for the gasification reaction in the gasifier; the first mixed gas is heat exchanged to form the second mixed gas; The second mixed gas enters the dryer to dry the biomass, thereby generating the dry biomass required in step 1; The second mixed gas forms a third mixed gas after the second heat exchange; The third mixed gas then enters the tar separation device for tar separation; The temperatures of the first mixed gas, the second mixed gas, and the third mixed gas decrease gradually.

4. The method according to claim 1, characterized in that The biomass drying temperature in step 1 is in the range of 100-150°C; the operating temperature range of the gasifier in step 3 is 900-1500°C; the operating temperature range of the pyrolysis furnace in step 4 is 200-1000°C; the temperature range of the water vapor shift reaction in step 6 is 200-500°C.

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

6. The method according to claim 1, characterized in that The tar separation method in step 5 is a water washing method or an adsorption method.

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

8. A decarbonization and hydrogen production system for complementary gasification of biomass and coal, characterized in that: The system includes: An air preheater (1) is used to heat air (11) to generate hot air (12) and provide it to a burner (5); A dryer (7) is used to heat the biomass (29) to generate dry biomass (23), which is provided to the burner (5) as a combustion fuel, and according to the required biomass ratio of the fuel of the pyrolysis furnace (3), a portion of the dry biomass (26) is separated from the dry biomass (23) and provided to the pyrolysis furnace (3) as a pyrolysis fuel; the biomass ratio in the pyrolysis fuel is greater than or equal to 0; A burner (5) for burning the dry biomass (23) and the hot air (12) to generate heat (25) and a first flue gas (24) to provide heat for the gasifier (4); a gasifier (4) for heating the coke (18) and the gasifying agent from the pyrolysis furnace (3) by using the heat (25) and the first flue gas (24) so ​​as to gasify the coke (18) and generate synthesis gas (20); the flue gas discharged after the first flue gas provides heat for the gasifier is called the second flue gas (19); The coal pretreatment unit (2) pulverizes the coal (13) to generate coal (14) for pyrolysis, and provides the coal (14) to the pyrolysis furnace (3); the coal (14) and the partially dried biomass (26) from the dryer are mixed to form pyrolysis fuel; The pyrolysis furnace (3) is used to utilize the heat of the second flue gas (19) to pyrolyze the pyrolysis fuel to generate pyrolysis gas (17) and coke (18); the coke (18) is fed back to the gasification furnace (4); A mixed gas heat utilization component is used to collect the synthesis gas (20) and the pyrolysis gas (17) to form a mixed gas, and output it to the tar separation device (8) after heat exchange; A tar separation device (8) for separating tar (30) from the mixed gas to generate a pure mixed gas (31); A water vapor converter (9) converts carbon monoxide in the pure mixed gas (31) into carbon dioxide and hydrogen through a water vapor conversion reaction to obtain a conversion 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 hydrogen (34) with higher purity.

9. The decarbonization and hydrogen production system of biomass and coal complementary gasification as claimed in claim 8, characterized in that: The second flue gas is the flue gas exhausted after the pyrolysis furnace (3) provides heat, and is called the third flue gas (15); the third flue gas (15) is provided with heat by the air preheater (1) and is used to preheat the air.

10. The decarbonization and hydrogen production system of biomass and coal complementary gasification as claimed in claim 8, characterized in that: The mixed gas heat utilization component uses a heat exchanger (6) to perform heat exchange on the mixed gas composed of the synthesis gas (20) and the pyrolysis gas (17) to preheat the gasifying agent (21) to form a high-temperature gasifying agent (22) and provide it to the gasifier (4); After heat exchange, the mixed gas forms a second mixed gas (27), which enters the dryer (7) to provide heat for heating the biomass (29); after heat exchange in the dryer (7), the second mixed gas forms a third mixed gas (28), which enters the tar separation device (8) for tar separation; the temperatures of the mixed gas, the second mixed gas (27) and the third mixed gas (28) decrease gradually.

Images