Method and system for coupling biomass solid waste to generate power and preparing biomass charcoal foaming agent for steelmaking

Abstract

The invention provides a method and system for coupling biomass solid waste to generate power and preparing a biomass charcoal foaming agent for steelmaking, and relates to the field of solid waste treatment. The method comprises the following steps: gasifying one part of biomass solid waste through a gasification furnace to obtain gasified carbon and biomass gas, and carbonizing the other part of biomass solid waste through a carbonization furnace; the carbonization comprises a low-temperature pyrolysis stage, a high-temperature pyrolysis stage and a slow cooling stage which are carried out in sequence; when the total amount of the pyrolysis gas generated by the carbonization furnace is less than or equal to 15-25Nm < 3 > / h, completing carbonization to obtain pyrolytic carbon; and compounding the gasified carbon and the pyrolytic carbon to obtain the biomass carbon foaming agent for steelmaking. According to the method provided by the invention, the obtained gas is utilized to generate power while the charcoal product suitable for the electric furnace steelmaking foaming agent is prepared, so that the deep utilization of biomass solid wastes is realized.

Description

Technical Field

[0001] The present application relates to the field of solid waste treatment, and particularly to a method and system for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking. Background Art

[0002] Biomass solid waste has characteristics such as large stockpiles and being renewable. However, the disposal of biomass solid waste has problems such as high costs, the value of the resulting products needing to be improved, and a general market prospect.

[0003] As an ideal foaming agent alternative carbon source in the electric arc furnace steelmaking process, biochar has significant advantages in reducing carbon emissions. However, the current production of biochar faces dual challenges: on the one hand, in the pyrolysis process with biochar as the target product, the conversion rate of biomass raw materials is relatively low, about 3 tons of raw materials can produce 1 ton of biochar, resulting in high costs and being unfavorable for industrial applications in electric arc furnace steelmaking; on the other hand, in the gasification process with biomass gas as the target product, although biochar is produced as a by-product, its output is relatively small and it is difficult to meet the large demand for biochar in electric arc furnace steelmaking.

[0004] Therefore, how to solve the problems of the price and output of producing biochar from biomass solid waste, and obtain biochar that can effectively reduce the power consumption in the smelting process of electric arc furnace steelmaking, reduce the consumption of biochar per ton of steel, and significantly shorten the smelting time has become the key to its industrial-scale application in the field of electric arc furnace steelmaking. Summary of the Invention

[0005] The purpose of the present application is to provide a method and system for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking to solve the above problems.

[0006] To achieve the above purpose, the present application adopts the following technical solutions: A method for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking, comprising: Gasifying a part of the biomass solid waste through a gasifier to obtain gasified carbon and biomass gas, and carbonizing another part of the biomass solid waste through a carbonizer; the carbonization includes a low-temperature pyrolysis stage, a high-temperature pyrolysis stage, and a slow cooling stage carried out in sequence; When carrying out the low-temperature pyrolysis stage, part of the biomass gas is input into the combustion chamber of the carbonizer as a carbonization heat source, and the excess biomass gas is purified and sent to a generator set for power generation; all the pyrolysis gas generated by the carbonizer is circulated back to the combustion chamber of the carbonizer as a carbonization heat source; the pyrolysis temperature of the low-temperature pyrolysis stage is 300 - 400 °C; After the low-temperature pyrolysis stage is completed, the amount of the biomass gas input into the carbonization furnace is increased so that the pyrolysis temperature rises to 600-700°C; when the pyrolysis gas can maintain the pyrolysis temperature at 600-700°C, all of the biomass gas is sent to the generator set to generate electricity; When the pyrolysis temperature is higher than 700°C, the high-temperature pyrolysis stage is completed, and the pyrolysis gas of a specific volume flow rate is purified and sent to the generator set for power generation, so that the pyrolysis temperature is gradually reduced; when the total amount of pyrolysis gas generated by the carbonization furnace is less than or equal to the specific volume flow rate, the pyrolysis gas is stopped from being sent to the generator set; The total amount of pyrolysis gas generated by the carbonization furnace is less than or equal to 15-25Nm 3 / h, carbonization is completed and pyrolytic carbon is obtained; The gasification carbon and the pyrolysis carbon are compounded to obtain a biomass carbon foaming agent for steelmaking.

[0007] Preferably, when the biomass solid waste is straw and the amount is less than 1 ton, the specific volume flow rate is 55-70 Nm 3 / h, and for every additional ton of usage, the specific volume flow rate increases by 30-40 Nm 3 / h.

[0008] Preferably, when the biomass solid waste is woody and the amount is less than 1 ton, the specific volume flow rate is 40-50 Nm 3 / h, and for every additional ton of usage, the specific volume flow rate increases by 20-30 Nm 3 / h.

[0009] Preferably, when the biomass solid waste is fruit shells and the amount is less than 1 ton, the specific volume flow rate is 25-40 Nm 3 / h, and for every additional ton of usage, the specific volume flow rate increases by 5-15Nm 3 / h.

[0010] If the actual volume flow rate of pyrolysis gas input to the generator set is lower than the specific volume flow rate range, the temperature of the carbonization furnace will be too high, which will cause the pyrolysis carbon output to decrease, and the heat of the pyrolysis gas will be difficult to use efficiently, increasing the cost of the composite biochar product. If the actual volume flow rate of pyrolysis gas input to the generator set is higher than the specific volume flow rate range, the temperature of the carbonization furnace will be too low, the pyrolysis carbon will not be completely carbonized, and the reactivity will increase significantly, resulting in a decrease in the carbon yield of the composite biochar product during the use of electric furnace steelmaking.

[0011] Therefore, it is particularly important to study the types of biomass raw materials, the corresponding specific volume flow, the usage and the acquisition of pyrolytic carbon, as well as the relationship between the production quality of pyrolytic carbon and the addition amount and carbon yield in the steelmaking process.

[0012] Preferably, the fixed carbon content of the gasified carbon after removing moisture is not less than 80%.

[0013] Preferably, the fixed carbon content of the pyrolytic carbon after removing moisture is not less than 70%.

[0014] Preferably, the biomass carbon foaming agent for steelmaking includes a composite biomass carbon foaming agent for top feeding, a composite biomass carbon foaming agent for lance injection into the furnace wall and / or furnace door, and a composite biomass carbon foaming agent for lance injection into the slag; In the composite biomass carbon foaming agent for top feeding, the content of the gasified carbon is 30-40 wt%, the total volatile content is not higher than 10 wt%, and the particle size of the composite foaming agent is 10-150 mm; In the composite biomass carbon foaming agent for lance injection into the furnace wall and / or furnace door, the content of the gasified carbon is 20-30 wt%, the total volatile content is not higher than 15 wt%, and the particle size of the composite foaming agent is not more than 3 mm; In the composite biomass carbon foaming agent for lance injection into the slag, the content of the gasified carbon is 10-20 wt%, the total volatile content is not higher than 20 wt%, and the particle size of the composite foaming agent is not more than 5 mm.

[0015] Preferably, the moisture content of the biomass carbon foaming agent for steelmaking is not higher than 3 wt%.

[0016] Preferably, the raw material of the biomass carbon foaming agent for steelmaking further includes a binder, and the addition amount of the binder is 0.5%-5% of the total mass of the gasified carbon and the pyrolytic carbon.

[0017] Preferably, the particle size of the biomass solid waste is 50-150 mm, and the moisture content is not higher than 15 wt%.

[0018] This application also provides a system for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking, including: A gasifier for processing biomass solid waste and generating gasified carbon and biomass gas; A carbonization furnace for processing biomass solid waste and generating pyrolytic carbon and pyrolysis gas; A pyrolysis gas recovery device for recovering the pyrolysis gas from the carbonization furnace; A gas purification device for purifying the biomass gas and the pyrolysis gas from the pyrolysis gas recovery device; A power generation unit for generating electricity by using the biomass gas and the pyrolysis gas; The gasifier is connected to the carbonization furnace and the gas purification device. The gas outlet of the carbonization furnace is connected to the inlet of the pyrolysis gas recovery device. The gas outlet of the pyrolysis gas recovery device is connected to the carbonization furnace and the gas purification device. The gas outlet of the gas purification device is connected to the power generation unit.

[0019] Preferably, the carbonization furnace is an intermittent carbonization furnace, and the capacity of a single intermittent carbonization furnace is not less than 4 cubic meters.

[0020] Compared with the prior art, the beneficial effects of the present application include: The method and system for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking provided by the present application use biomass solid waste as a raw material, and perform heat treatment in a gasifier and a carbonization furnace respectively to obtain gasified carbon and pyrolyzed carbon for compounding to obtain a biochar product suitable for an electric furnace steelmaking foaming agent. In this process, pyrolysis gas and biomass gas are used as the heat source of the carbonization furnace, and at the same time, the excess pyrolysis gas and biomass gas are incorporated into the gas purification device and finally transported to the power generation unit, which can improve the utilization value of pyrolysis gas and biomass gas and realize the efficient and low-carbon preparation of biochar. At the same time, this method relies on the existing facilities of a biomass power plant and only needs to supplement a pyrolysis system and a pretreatment system, with low equipment investment, thereby significantly reducing the production cost of biochar. In addition, the biochar product prepared by this method has a higher fixed carbon content compared with traditional pyrolysis biochar, can effectively reduce the power consumption in the smelting process of electric furnace steelmaking, reduce the consumption of biochar per ton of steel, and greatly shorten the smelting time. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope of the present application.

[0022] Figure 1 It is a schematic diagram of a system for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking provided for the embodiment. Detailed Embodiments

[0023] The following will describe the implementation solutions of the present application in detail with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0024] Example 1 As Figure 1As shown in the figure, this embodiment provides a system for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking, which specifically includes: a gasifier, a carbonization furnace, a pyrolysis gas recovery device, a gas purification device, and a generator set; The gasifier is used to process biomass solid waste and generate gasified carbon and biomass gas. The carbonization furnace is used to process biomass solid waste and generate pyrolytic carbon and pyrolysis gas. The pyrolysis gas recovery device is used to recover the pyrolysis gas from the carbonization furnace. The gas purification device is used to purify the biomass gas and the pyrolysis gas from the pyrolysis gas recovery device. The generator set is used to generate electricity using the biomass gas and the pyrolysis gas; The gas outlet of the gasifier is connected to the carbonization furnace and the gas purification device. The gas outlet of the carbonization furnace is connected to the inlet of the pyrolysis gas recovery device. The gas outlet of the pyrolysis gas recovery device is connected to the carbonization furnace and the gas purification device. The gas outlet of the gas purification device is connected to the generator set.

[0025] In an alternative embodiment, the carbonization furnace is an intermittent carbonization furnace, and the capacity of a single intermittent carbonization furnace is not less than 4 cubic meters.

[0026] In other alternative embodiments, multiple carbonization furnaces and gasifiers can be provided.

[0027] Embodiment 2 This embodiment provides a method for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking.

[0028] The biomass solid waste in the gasifier is peach wood, and the biomass solid waste in the carbonization furnace is corn straw. The particle sizes are both 150 mm, and the moisture contents are both 5 wt%. The system provided in Embodiment 1 is used (wherein, there are 2 carbonization furnaces, and the capacity of a single furnace is 5 m 3 , and a single furnace can carbonize 1 t of biomass raw material each time).

[0029] The peach wood is gasified in the gasifier to obtain gasified carbon and biomass gas. The corn straw is carbonized in the carbonization furnace. The carbonization includes the following steps: Low-temperature pyrolysis stage: At the initial stage, since no pyrolysis gas is generated in the carbonization furnace, the biomass gas generated by the gasifier is used as the heat source to maintain the pyrolysis temperature of the carbonization furnace at 350 °C for low-temperature carbonization, so as to reduce the porosity of the biochar product and improve the yield of the biochar product. As the pyrolysis progresses, since the calorific value of the pyrolysis gas generated in this stage is relatively low, all of it is recycled to the combustion chamber of the carbonization furnace to provide heat for pyrolysis. At the same time, the input amount of the biomass gas is reduced to ensure the stability of the pyrolysis temperature. When the pyrolysis gas can maintain the temperature of the carbonization furnace alone, it enters the high-temperature pyrolysis stage.

[0030] High-temperature pyrolysis stage: Increase the flow rate of the biomass gas to ensure that the temperature of the carbonization furnace rises to 600 °C within 8 minutes, so as to improve the graphitization degree of the biochar product, which is beneficial to reducing its reactivity and thus reducing the burning loss rate when using the biochar product in electric arc furnace steelmaking. When the pyrolysis gas can maintain the temperature of the carbonization furnace alone, close the input of the biomass gas, and all the carbonization heat sources are provided by the pyrolysis gas.

[0031] Slow cooling stage: When the temperature of the carbonization furnace exceeds 700 °C, part of the pyrolysis gas is input into the pipeline before the gas purification device at a volume flow rate of 60 Nm 3 The carbonization furnace uses the remaining pyrolysis gas as the heat source. As the pyrolysis process proceeds, the flow rate of the pyrolysis gas gradually decreases, and the carbonization furnace cools down slowly. When the total generated flow rate of the pyrolysis gas is less than the above-mentioned specific volume flow rate of the pyrolysis gas, stop the input of the pyrolysis gas into the gasification system. When the total generated volume flow rate of the pyrolysis gas is less than 20 Nm 3 The pyrolysis process ends.

[0032] The fixed carbon content of the obtained gasified carbon after removing moisture is 85%, and the fixed carbon content of the obtained pyrolyzed carbon after removing moisture is 74%.

[0033] The mixing mass ratio of the gasified carbon and pyrolyzed carbon of the biochar composite foaming agent prepared by this system is 3:7, the total volatile content is 7 wt%, the particle size of the composite foaming agent is 120 mm, and it is used as a foaming agent in the 100 t electric arc furnace scrap steel + 20% hot metal smelting process, and the feeding method is top feeding.

[0034] The production cost of preparing biochar by this method is 800 yuan lower than that of traditional pyrolysis for biochar preparation, and the biochar yield is 3 times higher than that of traditional gasification power generation. In addition, compared with the biochar prepared by the traditional pyrolysis process, the consumption of biochar in electric arc furnace steelmaking can be reduced by 5 kg / ton of steel.

[0035] Example 3 This example provides a method for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking.

[0036] The biomass solid waste in the gasification furnace is coconut shell, and the carbonization furnace contains a mixed material of rice straw and corn straw, with a particle size of 70 mm and a moisture content of 10 wt%. The system provided in Example 1 is used (wherein, there is 1 carbonization furnace with a single capacity of 15 m 3 , and each single furnace can carbonize 3 t of biomass raw materials at a time).

[0037] The coconut shell is gasified in the gasification furnace to obtain gasified carbon and biomass gas. The mixed material of rice straw and corn straw is carbonized in the carbonization furnace. The carbonization includes the following steps: Low-temperature pyrolysis stage: In the initial stage, since no pyrolysis gas is produced in the carbonization furnace, the biogas generated by the gasifier is used as the heat source to maintain the pyrolysis temperature of the carbonization furnace at 400 °C for low-temperature carbonization, so as to reduce the porosity of the biochar product and increase the yield of the biochar product. As the pyrolysis progresses, since the calorific value of the pyrolysis gas generated in this stage is relatively low, it is all recycled to the combustion chamber of the carbonization furnace to provide heat for pyrolysis. At the same time, the input amount of biogas is reduced to ensure the stability of the pyrolysis temperature. When the pyrolysis gas can maintain the temperature of the carbonization furnace alone, it enters the high-temperature pyrolysis stage.

[0038] High-temperature pyrolysis stage: Increase the biogas flow rate to ensure that the temperature of the carbonization furnace rises to 700 °C within 10 minutes, so as to increase the graphitization degree of the biochar product, which is beneficial to reducing its reactivity, thereby reducing the burn-off rate when using the biochar product in electric arc furnace steelmaking. When the pyrolysis gas can maintain the temperature of the carbonization furnace alone, the input of biogas is closed, and all the carbonization heat sources are provided by the pyrolysis gas.

[0039] Slow cooling stage: When the temperature of the carbonization furnace exceeds 700 °C, part of the pyrolysis gas is input into the pipeline before the gas purification device at a volume flow rate of 130 Nm 3 The carbonization furnace uses the remaining pyrolysis gas as the heat source. As the pyrolysis process progresses, the flow rate of the pyrolysis gas gradually decreases, and the carbonization furnace cools slowly until the total generated flow rate of the pyrolysis gas is less than the above-mentioned specific volume flow rate of the pyrolysis gas, and the input of the pyrolysis gas to the gasification system is stopped. When the total generated volume flow rate of the pyrolysis gas is less than 15 Nm 3 , the pyrolysis process ends.

[0040] The fixed carbon content of the obtained gasified carbon after removing moisture is 89%, and the fixed carbon content of the obtained pyrolyzed carbon after removing moisture is 76%.

[0041] The mixing mass ratio of the gasified carbon and pyrolyzed carbon of the biochar composite foaming agent prepared by this system is 1:4, the total volatile content is 12 wt%, the particle size of the composite foaming agent is 2 mm, and it is used as a foaming agent in the 80t electric arc furnace full scrap steel smelting process, and the feeding method is blowing through a carbon lance on the furnace wall.

[0042] The production cost of preparing biochar by this method is 600 yuan lower than that of preparing biochar by traditional pyrolysis, and the biochar output is 3 times higher than that of traditional gasification power generation. In addition, compared with the biochar prepared by the traditional pyrolysis process, the usage amount of biochar in electric arc furnace steelmaking can be reduced by 3 kg / ton of steel.

[0043] Example 4 This example provides a method for coupling biomass solid waste power generation and preparing a biomass carbon foaming agent for steelmaking.

[0044] The biomass solid waste in the gasifier is corn straw, and the material in the carbonization furnace is peach wood. The particle size of both is 80 mm, and the moisture content is 5 wt%. The system provided in Example 1 is used (wherein, there are 3 carbonization furnaces, with a single capacity of 12 m 3 , and each carbonization furnace can carbonize 3 t of biomass raw materials per single operation).

[0045] The peach wood is gasified in the gasifier to obtain gasified carbon and biogas. The corn straw is carbonized in the carbonization furnace. The carbonization includes the following steps: Low-temperature pyrolysis stage: At the initial stage, since there is no pyrolysis gas generated in the carbonization furnace, the biogas generated by the gasifier is used as the heat source to maintain the pyrolysis temperature of the carbonization furnace at 300 °C for low-temperature carbonization, so as to reduce the porosity of the biochar product and increase the yield of the biochar product. As the pyrolysis progresses, since the calorific value of the pyrolysis gas generated in this stage is relatively low, all of it is recycled to the combustion chamber of the carbonization furnace to provide heat for pyrolysis. At the same time, the input amount of biogas is reduced to ensure the stability of the pyrolysis temperature. When the pyrolysis gas can maintain the temperature of the carbonization furnace alone, it enters the high-temperature pyrolysis stage.

[0046] High-temperature pyrolysis stage: Increase the biogas flow rate to ensure that the temperature of the carbonization furnace rises to 600 °C within 5 minutes, so as to increase the graphitization degree of the biochar product, which is beneficial to reducing its reactivity, thereby reducing the burn-off rate when using the biochar product in electric arc furnace steelmaking. When the pyrolysis gas can maintain the temperature of the carbonization furnace alone, close the input of biogas, and all the carbonization heat source is provided by the pyrolysis gas.

[0047] Slow cooling stage: When the temperature of the carbonization furnace exceeds 700 °C, part of the pyrolysis gas is input into the pipeline before the gas purification device at a volume flow rate of 100 Nm 3 . The carbonization furnace uses the remaining pyrolysis gas as the heat source. As the pyrolysis process progresses, the flow rate of the pyrolysis gas gradually decreases, and the carbonization furnace cools down slowly. When the total generated flow rate of the pyrolysis gas is less than the above-mentioned specific volume flow rate of the pyrolysis gas, stop the input of the pyrolysis gas into the gasification system. When the total generated volume flow rate of the pyrolysis gas is less than 25 Nm 3 , the pyrolysis process ends.

[0048] The fixed carbon content of the obtained gasified carbon after removing moisture is 82%, and the fixed carbon content of the obtained pyrolyzed carbon after removing moisture is 78%.

[0049] The mixing mass ratio of the gasified carbon and the pyrolyzed carbon of the biochar composite foaming agent prepared by this system is 1:9, the total volatile content is 15 wt%, the particle size of the composite foaming agent is 5 mm, and it is used as a foaming agent in the 120 t electric arc furnace scrap steel + 30% direct reduced iron smelting process. The feeding method is in-furnace slag injection.

[0050] The production cost of preparing biochar using this method is 650 yuan lower than that of preparing biochar by traditional pyrolysis, and the biochar yield is 4 times higher than that of traditional gasification power generation. In addition, compared with the biochar prepared by traditional pyrolysis process, the usage amount of biochar for electric arc furnace steelmaking can be reduced by 4 kg / ton of steel.

[0051] Comparative Example 1 If the gasification furnace in Example 2 is used for separate gasification power generation, the biomass solid waste in the gasification furnace is peach wood, with a particle size of 150 mm and a moisture content of 5 wt%. The peach wood biochar that can be prepared per hour is 0.35 t, which is 1 / 3 of the composite biochar yield in Example 2. This kind of gasification char is used as a foaming agent in the 100 t electric arc furnace scrap + 20% hot metal smelting process by top feeding, with a particle size of 120 mm. The biochar usage amount per ton of steel is 20.5 kg / ton of steel, which can only reduce the biochar usage amount per ton of steel by 0.5 kg compared with that in Example 2 for electric arc furnace steelmaking. However, due to the low yield, the preparation cost of the composite biochar in Example 2 increases by 500 yuan.

[0052] Comparative Example 2 If 2 carbonization furnaces in Example 2 are used for separate carbonization, the biomass solid waste in the carbonization furnace is corn straw, with a particle size of 150 mm and a moisture content of 5 wt%. The corn straw biochar that can be prepared per hour is 0.7 t, and the preparation cost per ton of biochar is 2000 yuan, which is 800 yuan higher than the preparation cost of the composite biochar in Example 2. This kind of pyrolysis char is used as a foaming agent in the 100 t electric arc furnace scrap + 20% hot metal smelting process by top feeding, with a particle size of 120 mm. The biochar usage amount per ton of steel is 26 kg / ton of steel, which is 5 kg / ton of steel higher than the biochar usage amount per ton of steel in Example 2 for electric arc furnace steelmaking.

[0053] The method and system provided in this application can use the prepared biochar as a foaming agent for electric arc furnace steelmaking with all different charge structures such as 50 - 200 t of all scrap, scrap + hot metal, and scrap + direct reduced iron. The production cost of the biochar is 500 - 1000 yuan lower than that of preparing biochar by traditional pyrolysis, and the biochar yield is 3 - 6 times higher than that of traditional gasification power generation. In addition, the biochar usage amount for electric arc furnace steelmaking is reduced by 3 - 5 kg / ton of steel.

[0054] This application couples the biomass pyrolysis system with biomass gasification power generation, and by improving the utilization value of pyrolysis gas and reducing equipment investment, the production cost of biochar is greatly reduced. In addition, the biochars generated from the pyrolysis system and the gasification system are mixed in a specific ratio to prepare two high - efficiency foaming agents for electric arc furnace steelmaking. This foaming agent can stably and efficiently generate foamed slag during the smelting process, effectively reduce the power consumption during the smelting process, and greatly improve the smelting efficiency.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for coupling biomass solid waste power generation and preparing biomass charcoal foaming agent for steelmaking, characterized in that: include: A portion of the biomass solid waste is gasified by a gasifier to obtain gasified charcoal and biomass gas, and another portion of the biomass solid waste is carbonized by a carbonization furnace; the carbonization includes a low-temperature pyrolysis stage, a high-temperature pyrolysis stage and a slow cooling stage performed in sequence; During the low-temperature pyrolysis stage, part of the biomass gas is input into the combustion chamber of the carbonization furnace as a carbonization heat source, and the excess biomass gas is purified and sent to the generator set for power generation; all the pyrolysis gas generated by the carbonization furnace is circulated back to the combustion chamber of the carbonization furnace as a carbonization heat source; the pyrolysis temperature of the low-temperature pyrolysis stage is 300-400°C; After the low-temperature pyrolysis stage is completed, the amount of the biomass gas input into the carbonization furnace is increased so that the pyrolysis temperature rises to 600-700°C; when the pyrolysis gas can maintain the pyrolysis temperature at 600-700°C, all of the biomass gas is sent to the generator set to generate electricity; When the pyrolysis temperature is higher than 700°C, the high-temperature pyrolysis stage is completed, and the pyrolysis gas of a specific volume flow rate is purified and sent to the generator set for power generation, so that the pyrolysis temperature is gradually reduced; when the total amount of pyrolysis gas generated by the carbonization furnace is less than or equal to the specific volume flow rate, the pyrolysis gas is stopped from being sent to the generator set; The total amount of pyrolysis gas generated by the carbonization furnace is less than or equal to 15-25Nm 3 / h, carbonization is completed and pyrolytic carbon is obtained; The gasification carbon and the pyrolysis carbon are compounded to obtain a biomass carbon foaming agent for steelmaking.

2. The method for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to claim 1, characterized in that: When the biomass solid waste is straw and the amount is less than 1 ton, the specific volume flow rate is 55-70 Nm 3 / h, and for every additional ton of usage, the specific volume flow rate increases by 30-40 Nm 3 / h; When the biomass solid waste is woody and the amount is less than 1 ton, the specific volume flow rate is 40-50 Nm 3 / h, and for every additional ton of usage, the specific volume flow rate increases by 20-30 Nm 3 / h; When the biomass solid waste is fruit shells and the amount is less than 1 ton, the specific volume flow rate is 25-40 Nm 3 / h, and for every additional ton of usage, the specific volume flow rate increases by 5-15Nm 3 / h.

3. The method for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to claim 1, characterized in that: The fixed carbon content of the gasified carbon after removing moisture is not less than 80%.

4. The method for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to claim 1, characterized in that: The fixed carbon content of the pyrolytic carbon after removing moisture is not less than 70%.

5. The method for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to claim 1, characterized in that: The biomass carbon foaming agent for steelmaking includes a composite biomass carbon foaming agent for top feeding, a composite biomass carbon foaming agent for spraying with a furnace wall and / or furnace door spray gun, and a composite biomass carbon foaming agent for spraying in slag; In the composite biomass carbon foaming agent for top feeding, the content of gasified carbon is 30-40wt%, the total content of volatile matter is not higher than 10wt%, and the particle size of the composite foaming agent is 10-150mm; In the composite biomass charcoal foaming agent sprayed by the furnace wall and / or furnace door spray gun, the content of gasified char is 20-30wt%, the total content of volatile matter is not higher than 15wt%, and the particle size of the composite foaming agent is not greater than 3mm; In the composite biomass charcoal foaming agent for slag injection, the content of gasified char is 10-20wt%, the total content of volatile matter is not higher than 20wt%, and the particle size of the composite foaming agent is not greater than 5mm.

6. The method for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to claim 1, characterized in that: The water content of the biomass charcoal foaming agent for steelmaking is not higher than 3wt%.

7. The method for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to claim 1, characterized in that: The raw material of the biomass charcoal foaming agent for steelmaking also includes a binder, and the added amount of the binder is 0.5%-5% of the total mass of the gasification charcoal and the pyrolysis charcoal.

8. The method for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to any one of claims 1 to 7, characterized in that: The particle size of the biomass solid waste is 50-150 mm, and the moisture content is not higher than 15 wt %.

9. A system for coupling biomass solid waste power generation and preparing biomass charcoal foaming agent for steelmaking, characterized in that: include: A gasifier for treating biomass solid waste and producing gasification char and biomass gas; Carbonization furnace, used to process biomass solid waste and produce pyrolytic charcoal and pyrolytic gas; A pyrolysis gas recovery device, used for recovering the pyrolysis gas from the carbonization furnace; A gas purification device, used for purifying the biomass gas and the pyrolysis gas from the pyrolysis gas recovery device; A generator set, used for generating electricity by utilizing the biomass gas and the pyrolysis gas; The gasification furnace is connected to the carbonization furnace and the gas purification device, the gas outlet of the carbonization furnace is connected to the inlet of the pyrolysis gas recovery device, the gas outlet of the pyrolysis gas recovery device is connected to the carbonization furnace and the gas purification device, and the gas outlet of the gas purification device is connected to the generator set.

10. The system for coupling biomass solid waste power generation and preparing biomass carbon foaming agent for steelmaking according to claim 9, characterized in that: The carbonization furnace is an intermittent carbonization furnace, and the capacity of a single intermittent carbonization furnace is not less than 4 cubic meters.

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