Iron-making method and system based on coupled blowing of co 2-containing coal gas and biomass

Abstract

The present invention belongs to the technical field of blast furnace smelting and relates to an iron-making method and system based on coupled blowing of CO2-containing coal gas and biomass. The system of the present invention comprises: a material basic data storage and processing module; a material balance and heat balance measurement and calculation module; a biomass addition amount calculation module; a material basic parameter input module; a metallurgical process parameter input module; a smelting parameter constraint interval input module; and a low-carbon smelting parameter output module. A measurement and calculation method according to the present invention is based on the material balance and heat balance. On the premise that CO2-containing coal gas is blown in a blast furnace, the required blowing amount of the biomass and the corresponding coke ratio and coal ratio are calculated on the basis of the heat difference, and low-carbon smelting in the blast furnace is realized. The system and method can guide the blowing of CO2-containing coal gas in the blast furnace and determine the biomass addition amount; in addition, process parameters satisfying low-carbon smelting in the blast furnace can be obtained at any time according to the types and compositions of a fuel, a furnace burden, the CO2-containing coal gas, and the biomass, and compared with original smelting conditions, the purpose of reducing the fuel ratio can be achieved.

Description

Ironmaking method and system coupling CO2-containing gas and biomass injection Technical Field

[0001] The present invention belongs to the technical field of blast furnace smelting, and relates to an ironmaking method and system for coupling injection of CO2-containing coal gas and biomass. Background Art

[0002] As CO2 emissions become a global concern, steel mills, as major carbon emitters, urgently need a series of low-carbon smelting technologies to achieve low-carbon production and reduce CO2 emissions. The energy consumption and carbon emissions of the pre-iron system account for more than 70% of the entire steel production process. Energy conservation and emission reduction in blast furnace ironmaking is an important way to reduce energy consumption and pollutant emissions in steel mills. Generally speaking, for every ton of crude steel produced, about 4.2×10 6 kJ blast furnace gas, 4.1×10 6 kJ coke oven gas, 1.0×10 4 kJ converter gas and other waste gases within the plant are large by-products, but their recovery and utilization rates are low. Gases with high CO2 content, such as blast furnace gas and hot blast furnace exhaust, are treated and utilized even more efficiently. Most processes involve first removing the CO2 and then reusing it. This process is cumbersome, and the lower the CO2 content in the product gas, the higher the treatment cost and the smaller the product gas volume. Therefore, achieving efficient utilization of CO2-containing gas is crucial for reducing carbon emissions and production costs.

[0003] Under high temperature conditions, CO2 reacts with carbon to produce CO. Therefore, injecting CO2-containing gas into the blast furnace not only provides reducing gas for the furnace but also allows for efficient utilization of the CO2-containing gas, reducing carbon emissions. However, since the reaction between CO2 and carbon is endothermic, the addition of CO2 can lead to insufficient heat in the high-temperature zone of the blast furnace. Therefore, measures are needed to compensate for the heat of the blast furnace to meet production requirements. These measures primarily include adjusting process parameters, such as increasing the oxygen enrichment rate and the amount of coal injected, and adding heat-compensating materials, such as biomass and waste plastics. Adjusting process parameters increases the blast furnace's fuel efficiency. Biomass, a green and environmentally friendly energy source, contains low levels of sulfur and nitrogen, has a lower ash content than fossil fuels, and emits fewer pollutants. Therefore, injecting biomass into the blast furnace can provide heat compensation for the CO2-injected blast furnace while reducing the furnace's fuel efficiency, further enabling low-carbon smelting in steel mills.

[0004] Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an ironmaking method and system that couples CO2-containing gas with biomass injection, and comprehensively judges the injection amount of CO2-containing gas and the amount of heat compensation material added to solve the problem of low-carbon smelting in a blast furnace under the condition of injecting CO2-containing gas.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for calculating the amount of biomass added to a blast furnace, comprising the following steps:

[0008] S1 calculates the material balance and heat balance based on the target raw materials and process parameters to obtain the raw coke ratio and coal ratio that meet the requirements for smooth operation of the blast furnace;

[0009] S2 calculates the heat balance based on the amount of CO2-containing gas added, and calculates the initial biomass addition amount a0 based on the unit heat supply of biomass;

[0010] S3 calculates the material balance and heat balance according to the amount of biomass added. If the balance is not satisfied, the amount of biomass added is reduced according to the gradient k1 until the balance is satisfied.

[0011] After S4 satisfies S3, it determines whether the theoretical combustion temperature and gas utilization rate are within the constraint range. If not, the raw coke ratio and coal ratio are reduced according to the gradient k2, the absolute difference in heat balance and the corresponding biomass addition amount are calculated, and then it returns to S3, repeats S3 and S4 until the requirements of both steps are met at the same time, and outputs the smelting parameters.

[0012] Optionally, the judgment basis in step S2 is: |Relative difference between income and expenditure|=|(income-expenditure) / income*100%|<0.50%.

[0013] Optionally, the means of reducing the original coke ratio and coal ratio in step S4 include: fully reducing the coke ratio, fully reducing the coal ratio, and reducing the coke ratio and coal ratio at the same ratio at the same time.

[0014] A method for ironmaking by coupling CO2-containing gas with biomass injection,

[0015] Collect data on the composition, types and reserves of CO2-containing gas and biomass;

[0016] The biomass addition amount is calculated by the above method and the smelting parameters are output;

[0017] According to the smelting parameters, the blast furnace is guided to add biomass and inject CO2-containing gas.

[0018] Optionally, the CO2-containing gas injected into the blast furnace includes decarbonized and denitrified blast furnace gas, coke oven gas and CO2-containing industrial waste gas.

[0019] Optionally, under conditions of different CO2-containing coal gas and biomass types and compositions, the biomass addition amount, coke ratio and coal ratio corresponding to different injection amounts of CO2-containing coal gas are calculated.

[0020] An ironmaking system coupled with CO2-containing gas and biomass injection, including a background analysis system and a front-end use system;

[0021] The background analysis system includes: a material basic data storage and processing module; a material balance and heat balance calculation module; a biomass addition amount calculation module;

[0022] The front-end use system includes: a material basic parameter input module; a metallurgical process parameter input module; a smelting parameter constraint interval input module; and a low-carbon smelting parameter output module.

[0023] The calculation logic of the biomass addition amount calculation module is the method according to any one of claims 1-3.

[0024] Optionally, the material basic data storage and processing module stores the collected composition, reserves and performance index data of CO2-containing gas, biomass and other blast furnace materials, and processes missing values ​​and abnormal values.

[0025] Optionally, the material balance and heat balance calculation module calculates the composition and amount of furnace top gas, pig iron composition, gas amount and composition in the tuyere swirl zone, heat released by combustion in the furnace, and heat absorbed by reduction based on the given raw materials and process parameters, and determines whether the material balance and heat balance are achieved, and whether the parameter indicators of gas utilization rate and theoretical combustion temperature meet the constraints.

[0026] Optionally, the material basic parameter input module: the input parameters include: composition, reserves, calorific value and basic characteristic data of coke, coal powder, iron-containing furnace charge, biomass, and CO2-containing gas.

[0027] Optionally, the smelting process parameter input module: the input parameters include: blast furnace charge structure, blast furnace smelting element distribution rate, slag basicity, injection medium temperature, CO2-containing gas injection amount, direct reduction degree, and oxygen enrichment rate parameter values.

[0028] Optionally, the smelting parameter constraint interval input module is used to input the constraint range of theoretical combustion temperature and gas utilization rate.

[0029] Optionally, the low-carbon smelting parameter output module calculates the heat difference and outputs the coke ratio, coal ratio and corresponding biomass addition amount that meet the requirements of low-carbon smelting to guide the blast furnace to inject CO2-containing gas.

[0030] The beneficial effects of the present invention are:

[0031] Based on material balance and heat balance, the present invention theoretically guides the injection of CO2-containing gas into the blast furnace and determines the amount of heat compensation material (biomass) to be added. Based on the types and compositions of the raw fuel, CO2-containing gas, and heat compensation material, process parameters that meet the requirements for blast furnace low-carbon smelting can be readily obtained, thereby reducing the fuel ratio compared to the original smelting conditions. The required biomass injection amount and the values ​​of other important process parameters are calculated to achieve blast furnace low-carbon smelting.

[0032] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0034] FIG1 is a flow chart of a method for calculating the amount of biomass added to a blast furnace;

[0035] FIG2 is a flow chart of an ironmaking method coupling CO2-containing gas with biomass injection;

[0036] FIG3 is a schematic diagram of an ironmaking system that couples CO2-containing gas with biomass injection. DETAILED DESCRIPTION

[0037] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0038] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0039] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0040] Referring to Figures 1 to 3, the present invention first discloses a method for calculating the amount of biomass added, comprising the following steps:

[0041] S1: Calculate the material balance and heat balance based on the raw fuel composition, charge structure and production process parameters in the target plant to obtain the raw coke ratio and coal ratio of the target blast furnace;

[0042] S2: Based on the amount of CO2-containing gas added, keeping the original coke ratio, coal ratio and other process parameters unchanged, calculate the absolute difference in heat budget Q 差 = heat income - heat expenditure, and then according to the unit biomass heat supply q, the initial biomass addition amount a0 = ︱Q 差 ︱ / q, at this time the amount of biomass added is a=a0;

[0043] S3: Calculate whether the material balance and heat balance are achieved based on the calculated biomass addition amount a. The judgment basis is: ︱Relative difference between income and expenditure︱=︱(income-expenditure) / income*100%︱<0.50%. When the material balance and heat balance are not met, reduce the biomass addition amount according to a certain gradient k1 and then perform the balance calculation. k1 can be adjusted (as small as possible) until the material balance and heat balance are met. The biomass addition amount at this time is a i =a0-ik1 (i represents the number of times the amount of biomass added is reduced). When the material balance and heat balance are met, the next step of judgment and calculation is carried out;

[0044] S4: Determine the amount of biomass added in S3 i Calculate whether the theoretical combustion temperature and gas utilization rate obtained after material balance and heat balance are within the constraint range. When the above conditions are met, output the relevant smelting parameters. When the constraint range is not met, reduce the raw coke ratio and coal ratio according to the needs of the factory, reduce the gradient k2 adjustable (as small as possible), and keep other process parameters unchanged. Then calculate the absolute difference in heat balance and the corresponding biomass b1. The amount of biomass added at this time is a i+1 =a i+b1; The above-mentioned reduction of coke ratio and coal ratio according to plant demand includes: full coke reduction, full coal reduction, and simultaneous reduction of coke ratio and coal ratio in a certain proportion.

[0045] S5: According to the calculated amount of biomass added a i+1 Repeat steps S3 and S4 until the adjusted coke ratio, coal ratio and biomass addition amount satisfy the material balance and heat balance and the theoretical combustion temperature and gas utilization rate are within the constraint range, and output the corresponding smelting parameters.

[0046] The present invention also provides an ironmaking method that couples CO2-containing gas and biomass injection based on the above-mentioned measurement method, collects data such as the composition, type and reserves of CO2-containing gas (decarbonized and denitrified blast furnace gas, coke oven gas, CO2-containing industrial waste gas) and biomass, and processes missing values ​​and outliers in the data; calculates material balance and heat balance based on the target blast furnace raw fuel and process parameters to obtain the raw coke ratio and coal ratio that meet the requirements for smooth operation of the blast furnace; selects available basic data on CO2-containing gas and biomass, inputs the injection amount of CO2-containing gas and the constraint range of related parameters, keeps the other process parameters of the target blast furnace unchanged, and takes meeting the constraint range of gas utilization rate and theoretical combustion temperature as the goal, reduces the coke ratio and coal ratio according to demand, and calculates the amount of biomass added by the heat difference.

[0047] Blast furnace injection of CO2-containing gas, including decarbonized and denitrified blast furnace gas, coke oven gas, and CO2-containing industrial waste gas, reduces the CO2 concentration requirements of the CO2 removal process. Simultaneously, by adding biomass for heat compensation, it also reduces carbon emissions in steel mills. Based on material and heat balances, and within the constraints of smelting parameters, a biomass addition calculation model was constructed. Under conditions of varying CO2-containing gas and biomass types and compositions, the biomass addition amount, coke ratio, and coal ratio corresponding to varying CO2-containing gas injection rates were calculated. This allows for dynamic regulation of injection rates and some process parameters, achieving low-carbon smelting.

[0048] The present invention also provides an ironmaking system coupled with CO2-containing coal gas and biomass injection based on the aforementioned calculation method, comprising a backend analysis system and a frontend user system. The backend analysis system includes a material basic data storage and processing module; a material balance and heat balance calculation module; and a biomass addition calculation module. The frontend user system includes a material basic parameter input module; a metallurgical process parameter input module; a smelting parameter constraint range input module; and a low-carbon smelting parameter output module.

[0049] The function of the material basic data storage and processing module is to store the collected CO2-containing gas (decarbonized and denitrified blast furnace gas, coke oven gas, CO2-containing industrial waste gas), biomass and other blast furnace materials, such as composition, reserves and performance index data, and process missing values ​​and abnormal values, wherein the CO2 content ranges from 1% to 10%. The material balance and heat balance calculation module calculates the top gas composition and gas volume, pig iron composition, tuyere swirl zone gas volume and composition, furnace combustion heat release, reduction heat absorption according to the given raw materials and process parameters, and judges whether the material balance and heat balance, gas utilization rate, theoretical combustion temperature and other parameter indicators meet the actual requirements; the parameters input by the material basic parameter input module include: input of coke, coal powder, iron-containing furnace charge, biomass, CO2-containing gas composition, reserves, calorific value and basic characteristic data; the metallurgical process parameter input module The input parameters include: inputting the parameter values ​​of the target blast furnace charge structure, blast furnace smelting element distribution rate, slag alkalinity, injection medium temperature, CO2-containing gas injection amount, direct reduction degree, and oxygen enrichment rate; the parameters inputted by the smelting parameter constraint interval input module include: based on actual production and theoretical calculation experience, inputting the theoretical combustion temperature and gas utilization rate to meet the constraint range values ​​of blast furnace smelting; the low-carbon smelting parameter output module calculates the heat difference and outputs the coke ratio, coal ratio and corresponding biomass addition amount that meet the requirements of low-carbon smelting to guide the blast furnace injection of CO2-containing gas.

[0050] Example 1

[0051] Step 1: Get 3200m of a steel plant 3 Regarding the material situation of grade blast furnaces, a steel plant currently uses coke A, coal powder B, mixed ore and mixed solvents. In addition, it has decarbonized and denitrified blast furnace gas (containing 2% CO2) and biomass A.

[0052] Step 2: Calculate the initial coke ratio and coal ratio of the target blast furnace, and calculate the material balance and heat balance based on the target blast furnace raw fuel and process parameters. The original process parameters mainly include: the distribution rate of elements into pig iron: η Fe =99.75%, η Mn =60.05%; slag basicity R is 1.25; iron direct reduction degree r d The top gas temperature is 159℃, the oxygen enrichment rate is 0.01, etc. Without injecting CO2-containing gas, the original coke ratio C that meets the requirements of blast furnace operation is obtained. 焦0 and coal ratio C 煤0 , 355kg / t and 160kg / t respectively.

[0053] Step 3: Determine the CO2-containing gas injection volume V 气The range values ​​of parameters such as the biomass addition reduction gradient k1, the coke ratio and coal ratio reduction gradient k2, the gas utilization rate and the theoretical combustion temperature are obtained based on the historical production data collected from the steel plant's blast furnace and theoretical calculations. The range values ​​of important process parameters are: 0.48 ≤ gas utilization rate ≤ 0.49; 2100 ℃ ≤ theoretical combustion temperature ≤ 2250 ℃. According to the plant's demand and reserves, the CO2-containing gas injection rate is 40m 3 / t, the biomass addition reduction gradient value k1 is 0.05kg / t, and the coke ratio and coal ratio reduction gradient values ​​are 1kg / t.

[0054] Step 4: Calculation of the required heat compensation biomass injection amount corresponding to the blast furnace CO2-containing gas injection amount

[0055] S1: The amount of CO2-containing gas added is 40m 3 / t, keeping the original coke ratio, coal ratio and other process parameters unchanged, the absolute difference in heat budget is calculated to be -0.03GJ / t, the unit biomass heat supply is 0.025GJ / kg, and the initial biomass addition amount a0 is calculated to be 0.03 / 0.025=1.20kg / t. At this time, the biomass addition amount is a=a0=1.20kg / t;

[0056] S2: Calculate the material and heat balances based on the calculated biomass addition amount of 1.20 kg / t, the coke ratio and coal ratio of 355 kg / t and 160 kg / t, respectively. It is determined that the material balance and heat balance are satisfied, and the next step of judgment and calculation is carried out.

[0057] S3: The theoretical combustion temperature and gas utilization rate calculated based on S2 are 2192°C and 0.468, respectively. The gas utilization rate does not meet the constraint range. It is reduced according to the ratio of 1:1 between the coke ratio and the coal ratio, with a reduction gradient k2 of 1 kg / t. After the reduction, the gas utilization rate is 354 kg / t and 159 kg / t, respectively. Other process parameters remain unchanged. The absolute difference in heat budget is calculated to be -0.005 GJ / t, and the corresponding biomass b1 is 0.20 kg / t. The biomass addition amount at this time is a1 = a0 + b1 = 1.20 + 0.20 = 1.40 kg / t.

[0058] S4: Repeat steps S2 to S3 based on the calculated biomass addition amount a1. When repeated for the eighth time, the coke ratio and coal ratio are 347 kg / t and 152 kg / t, respectively, and the biomass addition amount is 5 kg / t. The calculation satisfies the material balance and heat balance, and the theoretical combustion temperature and gas utilization rate are 2186°C and 0.481, respectively, which are within the constraint range.

[0059] Step 5: The output coke ratio is 347 kg / t, the coal ratio is 152 kg / t, the biomass addition amount is 5 kg / t, the fuel ratio is reduced by 16 kg / t, and the calculation is completed.

[0060] Example 2

[0061] Step 1: Get 3200m of a steel plant 3 Regarding the material situation of the blast furnace, a steel plant currently uses coke A, coal powder B, mixed ore and mixed solvents. In addition, it has decarbonized and denitrified blast furnace gas (containing 5% CO2) and biomass A.

[0062] Step 2: Calculate the initial coke ratio and coal ratio of the target blast furnace, and calculate the material balance and heat balance based on the target blast furnace raw fuel and process parameters. The original process parameters mainly include: the distribution rate of elements into pig iron: η Fe =99.75%, η Mn =60.05%; slag basicity R is 1.25; iron direct reduction degree r d The top gas temperature is 159℃, the oxygen enrichment rate is 0.01, etc. Without injecting CO2-containing gas, the original coke ratio C that meets the requirements of blast furnace operation is obtained. 焦0 and coal ratio C 煤0 , 355kg / t and 160kg / t respectively.

[0063] Step 3: Determine the CO2-containing gas injection volume V 气 , the biomass addition reduction gradient value k1, the coke ratio and coal ratio reduction gradient value k2, the unit biomass heat supply, gas utilization rate and theoretical combustion temperature and other parameters range values, based on the collected historical production data of the steel plant's blast furnace and theoretical calculations, the range values ​​of important process parameters are obtained: 0.48 ≤ gas utilization rate ≤ 0.49; 2100 ℃ ≤ theoretical combustion temperature ≤ 2250 ℃. According to the plant's demand and reserves, the CO2-containing gas injection volume is 60m 3 / t, the biomass addition reduction gradient value k1 is 0.1kg / t, the unit biomass heat supply q is 0.025GJ / kg, the coke ratio and coal ratio reduction gradient value is 2kg / t, only the coal ratio is reduced.

[0064] Step 4: Calculation of the required heat compensation biomass injection amount corresponding to the blast furnace CO2-containing gas injection amount

[0065] S1: The amount of CO2-containing gas added is 60m 3 / t, keeping the original coke ratio, coal ratio and other process parameters unchanged, calculate the absolute difference in heat budget Q 差 =-0.075GJ / t, calculate the initial biomass addition amount a0=0.075 / 0.025=3.00kg / t, at this time the biomass addition amount is a=a0=3.00kg / t;

[0066] S2: Calculate the material and heat balances based on the calculated biomass addition amount of 3.00 kg / t, the coke ratio and the coal ratio of 355 kg / t and 160 kg / t, respectively. It is determined that the heat balance is not satisfied. The biomass addition amount is reduced to 2.90 kg / t and the material and heat balance calculations are repeated. The above steps are repeated until the biomass addition amount is reduced to 2.60 kg / t, which satisfies the material balance and heat balance. The next step of judgment and calculation is then carried out.

[0067] S3: Based on the theoretical combustion temperature and gas utilization rate calculated when the biomass addition amount is 2.60 kg / t in S2, which is 2140°C and 0.456 respectively, the gas utilization rate does not meet the constraint range. According to the coal reduction method, the coal ratio is reduced to 158 kg / t, and other process parameters remain unchanged. Then calculate the absolute difference in heat budget Q. 差 If the biomass addition rate is 0.002GJ / t, no more biomass is needed, i.e. b1 is 0kg / t. The biomass addition rate is a1=a0+b1=2.60+0=2.60kg / t.

[0068] S4: Repeat steps S2 to S3 based on the calculated biomass addition amount a1. When repeated for the 16th time, the coke ratio and coal ratio are 355 kg / t and 128 kg / t, respectively, and the biomass addition amount is 9.52 kg / t. The calculation satisfies the material balance and heat balance, and the theoretical combustion temperature and gas utilization rate are 2150°C and 0.482, respectively, which are within the constraint range.

[0069] Step 5: The output coke ratio is 355 kg / t, the coal ratio is 128 kg / t, the biomass addition amount is 9.52 kg / t, the fuel ratio is reduced by 32 kg / t, and the calculation is completed.

[0070] Example 3

[0071] Step 1: Get 3200m of a steel plant 3 Regarding the material situation of grade blast furnaces, a steel plant currently uses coke A, coal powder B, mixed ore and mixed solvents. In addition, it has decarbonized and denitrified blast furnace gas (containing 7% CO2) and biomass A.

[0072] Step 2: Calculate the initial coke ratio and coal ratio of the target blast furnace, and calculate the material balance and heat balance based on the target blast furnace raw fuel and process parameters. The original process parameters mainly include: the distribution rate of elements into pig iron: η Fe =99.75%, η Mn =60.05%; slag basicity R is 1.25; iron direct reduction degree r d The top gas temperature is 159℃, the oxygen enrichment rate is 0.01, etc. Without injecting CO2-containing gas, the original coke ratio C that meets the requirements of blast furnace operation is obtained.焦0 and coal ratio C 煤0 , 355kg / t and 160kg / t respectively.

[0073] Step 3: Determine the CO2-containing gas injection volume V 气 , the biomass addition reduction gradient value k1, the coke ratio and coal ratio reduction gradient value k2, the unit biomass heat supply, gas utilization rate and theoretical combustion temperature and other parameters range values. Based on the historical production data collected from the steel plant's blast furnace and theoretical calculations, the range values ​​of important process parameters are obtained: 0.47 ≤ gas utilization rate ≤ 0.49; 2100 ℃ ≤ theoretical combustion temperature ≤ 2250 ℃. According to the plant's demand and reserves, the CO2-containing gas injection volume is 60m 3 / t, the biomass addition reduction gradient value k1 is 0.1kg / t, the unit biomass heat supply q is 0.025GJ / kg, and the coke ratio and coal ratio reduction gradient value is 2kg / t, only the coke is reduced.

[0074] Step 4: Calculation of the required heat compensation biomass injection amount corresponding to the blast furnace CO2-containing gas injection amount

[0075] S1: The amount of CO2-containing gas added is 60m 3 / t, keeping the original coke ratio, coal ratio and other process parameters unchanged, calculate the absolute difference in heat budget Q 差 =-0.094GJ / t, calculate the initial biomass addition amount a0=0.094 / 0.025=3.73kg / t, at this time the biomass addition amount is a=a0=3.73kg / t;

[0076] S2: Calculate the material and heat balances based on the calculated biomass addition amount of 3.73 kg / t, the coke ratio and the coal ratio of 355 kg / t and 160 kg / t, respectively. It is determined that the heat balance is not satisfied. The biomass addition amount is reduced to 3.63 kg / t and the material and heat balance calculations are repeated. The above steps are repeated until the biomass addition amount is reduced to 3.13 kg / t, which satisfies the material balance and heat balance. The next step of judgment and calculation is then carried out.

[0077] S3: Based on the theoretical combustion temperature and gas utilization rate calculated when the biomass addition amount is 3.13 kg / t in S2, which is 2132°C and 0.455 respectively, the gas utilization rate does not meet the constraint range. By reducing the coke ratio, the coke ratio is reduced to 353 kg / t, and other process parameters remain unchanged. Then the absolute difference in heat budget Q is calculated. 差 =-0.0018GJ / t, then the biomass addition amount b1 is 0.07kg / t, and the biomass addition amount at this time is a1=a0+b1=3.13+0.07=3.20kg / t;

[0078] S4: Repeat steps S2 to S3 based on the calculated biomass addition amount a1. When repeated for the 13th time, the coke ratio and coal ratio are 329 kg / t and 160 kg / t, respectively, and the biomass addition amount is 10.10 kg / t. The calculation satisfies the material balance and heat balance, and the theoretical combustion temperature and gas utilization rate are 2100°C and 0.474, respectively, which are within the constraint range.

[0079] Step 5: The output coke ratio is 329 kg / t, the coal ratio is 160 kg / t, the biomass addition amount is 10.10 kg / t, the fuel ratio is reduced by 26 kg / t, and the calculation is completed.

[0080] Note: The biomass addition amount can be limited by the reserve. If the biomass addition amount exceeds the limit during the calculation process, it can be adjusted by reducing the CO2-containing gas injection rate or adjusting parameters such as the direct reduction degree. The calculation method remains unchanged. In addition, by performing multiple calculations under the same conditions, the biomass addition amount plan with the lowest fuel ratio can be obtained.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for calculating the amount of biomass added to a blast furnace, characterized in that: The following steps are involved: S1 calculates the material balance and heat balance based on the target raw materials and process parameters to obtain the raw coke ratio and coal ratio that meet the requirements for smooth operation of the blast furnace; S2 calculates the heat balance according to the amount of CO2-containing gas added, and calculates the initial biomass addition amount a0 according to the unit heat supply of biomass; S3 calculates the material balance and heat balance according to the amount of biomass added. If the balance is not satisfied, the amount of biomass added is reduced according to the gradient k1 until the material balance and heat balance are satisfied. After S4 satisfies S3, it determines whether the theoretical combustion temperature and gas utilization rate are within the constraint range. If not, it reduces the raw coke ratio and coal ratio according to the gradient k2, calculates the absolute difference in heat balance and the corresponding biomass addition amount, and then returns to S3, repeats S3 and S4, until the requirements of both steps are met at the same time, and outputs the smelting parameters.

2. The method for calculating the amount of biomass added to a blast furnace according to claim 1, characterized in that: The judgment basis in step S2 is: |Relative difference between income and expenditure|=|(income-expenditure) / income*100%|<0.50%.

3. The method for calculating the amount of biomass added to a blast furnace according to claim 1, characterized in that: The means for reducing the original coke ratio and coal ratio in step S4 include: reducing the coke ratio completely, reducing the coal ratio completely, and reducing the coke ratio and coal ratio at the same ratio at the same time.

4. An ironmaking method coupling CO2-containing gas and biomass injection, characterized in that: Collect data on the composition, type and reserves of CO2-containing gas and biomass; Calculate the amount of biomass added and output smelting parameters by the method according to any one of claims 1 to 3; According to the smelting parameters, the blast furnace is guided to add biomass and inject CO2-containing gas.

5. The ironmaking method of coupling CO2-containing gas and biomass injection according to claim 4, characterized in that: The CO2-containing gas injected into the blast furnace includes decarbonized and denitrified blast furnace gas, coke oven gas and CO2-containing industrial waste gas.

6. The ironmaking method of coupling CO2-containing gas and biomass injection according to claim 4, characterized in that: Under the conditions of different CO2-containing gas and biomass types and compositions, the biomass addition amount, coke ratio and coal ratio corresponding to different injection amounts of CO2-containing gas were calculated.

7. An ironmaking system coupling CO2-containing gas and biomass injection, characterized in that: Including backend analysis system and frontend usage system; The background analysis system includes: a material basic data storage and processing module; a material balance and heat balance calculation module; a biomass addition amount calculation module; The front-end use system includes: a material basic parameter input module; a metallurgical process parameter input module; a smelting parameter constraint interval input module; and a low-carbon smelting parameter output module; The calculation logic of the biomass addition amount calculation module is the method according to any one of claims 1-3.

8. The ironmaking system of coupling CO2-containing gas and biomass injection according to claim 7 is characterized in that: The material basic data storage and processing module stores the collected composition, reserves and performance index data of CO2-containing gas, biomass and other blast furnace materials, and processes missing values ​​and abnormal values.

9. The ironmaking system of coupling CO2-containing gas and biomass injection according to claim 7 is characterized in that: The material balance and heat balance calculation module calculates the composition and amount of furnace top gas, pig iron composition, gas amount and composition in the tuyere vortex zone, heat release from combustion in the furnace, and heat absorption from reduction according to the given raw materials and process parameters, and determines whether the material balance and heat balance are achieved, and whether the parameter indicators of gas utilization rate and theoretical combustion temperature meet the constraints.

10. The ironmaking system of coupling CO2-containing gas and biomass injection according to claim 7, characterized in that: The material basic parameter input module: the input parameters include: composition, reserves, calorific value and basic characteristic data of coke, coal powder, iron-containing charge, biomass, and CO2-containing gas.

11. The ironmaking system of claim 7, characterized in that: The smelting process parameter input module: the input parameters include: blast furnace charge structure, blast furnace smelting element distribution rate, slag basicity, injection medium temperature, CO2-containing gas injection amount, direct reduction degree, and oxygen enrichment rate parameter values.

12. The ironmaking system of claim 7, characterized in that: The smelting parameter constraint interval input module is used to input the constraint range of theoretical combustion temperature and gas utilization rate.

13. The ironmaking system of claim 7, characterized in that: The low-carbon smelting parameter output module calculates the heat difference, outputs the coke ratio, coal ratio and corresponding biomass addition amount that meet the requirements of low-carbon smelting, and guides the blast furnace to inject CO2-containing gas.

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