Method for optimizing initial gas flow distribution of furnace top gas circulating blast furnace

Abstract

The invention discloses a method for optimizing initial gas flow distribution of a furnace top gas circulation blast furnace. The method comprises the following steps: regarding a rotary area in front of a tuyere as a heat insulation environment; data required for calculating theoretical combustion temperature in front of each tuyere of the blast furnace is acquired by the data acquisition system and stored in a database for the theoretical combustion temperature calculation system and the blast kinetic energy calculation system to use; theoretical combustion temperatures and blast kinetic energy at the front ends of all tuyeres of the blast furnace are obtained through a theoretical combustion temperature calculation system and a blast kinetic energy calculation system respectively, and then the coal quantity and the gas injection quantity of each tuyere branch pipe are optimized and solved through an optimization algorithm on the premise that the total coal injection quantity and the total circulating gas injection quantity are guaranteed; and then the coal quantity and the gas injection quantity of each tuyere branch pipe are controlled through a tuyere coal injection flow automatic regulating valve and a tuyere gas injection flow automatic regulating valve. According to the method, the initial gas flow distribution of the blast furnace can be optimized, and the coal quantity and the gas injection quantity of each tuyere branch pipe can be effectively and automatically controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and in particular relates to a method for optimizing initial gas flow distribution in a blast furnace with top gas circulation. Background Art

[0002] The blast furnace ironmaking process based on traditional carbon metallurgy needs to achieve low-carbon green upgrades from the source to the end of the process. At present, the main technical schools are divided into two directions. The first is how to better improve the energy efficiency of the blast furnace process in order to minimize CO 2 emissions; the second is to adjust the energy structure to optimize the energy structure of the ironmaking process, such as the use of technologies such as hydrogen instead of carbon. From the current research and development progress, although method 2 has the advantages of fast reduction speed, high efficiency and clean reduction products, it is technically difficult and has high consumption. On the contrary, method 1 has relatively small process changes, less investment, and high efficiency, which is more suitable for the current stage. One of the more representative methods is the blast furnace top gas circulation process, which is to decarbonize the top gas and then spray it into the blast furnace again to increase the CO content in the furnace, increase the reduction potential, and improve the indirect reduction capacity of the blast furnace, thereby reducing the blast furnace coke consumption and reducing CO. 2 However, the injection of circulating gas will lead to differences in the theoretical combustion temperature or blast kinetic energy between the tuyere of the blast furnace that injects reducing gas and the tuyere that does not inject reducing gas, thereby affecting the initial gas distribution at the front end of each tuyere, and further making the circumferential gas flow distribution of the blast furnace uneven, affecting the blast furnace production. Therefore, it is an urgent problem to develop a method for optimizing the initial gas flow distribution of the top gas circulation blast furnace. Summary of the invention

[0003] The present invention aims to provide a method for optimizing the initial gas flow distribution of a top gas circulating blast furnace, so as to solve the problems existing in the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A method for optimizing the initial gas flow distribution of a top gas circulation blast furnace comprises the following steps:

[0006] The whirlpool area in front of the tuyere is regarded as an adiabatic environment; the data required for calculating the theoretical combustion temperature in front of each tuyere of the blast furnace is collected through the data acquisition system, and stored in the database for use by the theoretical combustion temperature calculation system and the blast kinetic energy calculation system;

[0007] The theoretical combustion temperature and blast kinetic energy of all tuyere front ends of the blast furnace are obtained respectively by the theoretical combustion temperature calculation system and the blast kinetic energy calculation system. Then, the coal amount and gas injection amount of each tuyere branch are optimized and solved under the premise of ensuring the total coal injection amount and the total circulating gas injection amount through the optimization algorithm. Then, the coal amount and gas injection amount of each tuyere branch are controlled through the tuyere coal injection flow automatic regulating valve and the tuyere gas injection flow automatic regulating valve.

[0008] Furthermore, the data required for calculating the theoretical combustion temperature in front of each tuyere of the blast furnace include but are not limited to the flow rate and temperature of the circulating gas, the cold air flow rate, the hot air temperature, the hot air pressure, the composition of the injected circulating gas, the oxygen enrichment rate and amount of the blast furnace, the coke composition, the composition of the injected coal powder, the coal powder injection amount, the number of blast furnace tuyere and the injection tuyere position and blast humidity of the circulating gas.

[0009] Furthermore, the optimization algorithm is a genetic algorithm.

[0010] Furthermore, the method for controlling the coal amount of each tuyere branch pipe is: under the premise of ensuring the total coal powder injection amount, gradually reduce the injection amount of the circulating gas tuyere, and increase the coal powder injection amount of the non-injected tuyere, until the error between the two is within the specified range.

[0011] Furthermore, the method for controlling the gas injection amount of each air outlet branch pipe is: when the theoretical combustion temperature meets the demand, calculate the blast kinetic energy at the front end of each air outlet, and compare whether the current blast kinetic energy of each air outlet is within the specified threshold range. If not, optimize it by adjusting the size of the air outlet that sprays circulating gas and the air outlet that does not spray circulating gas.

[0012] The method can be used to optimize the initial gas flow distribution of the blast furnace, and effectively and automatically control the coal amount and gas injection amount of each tuyere branch pipe, so that the difference in theoretical combustion temperature at the front end of each tuyere is less than a specified threshold, thereby ensuring the uniformity of the initial gas flow temperature field; at the same time, the difference in blast kinetic energy at the front end of each tuyere is less than a specified threshold, thereby ensuring the energy uniformity of the circumferential gas at the tuyere of the blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a flow chart of optimizing the initial gas flow distribution of a blast furnace with top gas circulation according to the present invention. DETAILED DESCRIPTION

[0014] To further illustrate various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in this field should be able to understand other possible implementations and advantages of the present invention.

[0015] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0016] like Figure 1 As shown, the present invention provides a method for optimizing the initial gas flow distribution of a blast furnace with top gas circulation, and the method involves a data acquisition system, a theoretical combustion temperature calculation system, a blast kinetic energy calculation system, an automatic regulating valve for coal injection flow at the tuyere, and an automatic regulating valve for gas injection flow at the tuyere, etc., which are related to the tuyere tuyere. The data acquisition system generally refers to a collection of sensors for collecting various blast furnace parameters; the theoretical combustion temperature calculation system and the blast kinetic energy calculation system generally refer to a computer system or computer program for performing theoretical combustion temperature calculation and blast kinetic energy calculation.

[0017] The specific steps include:

[0018] The swirling zone in front of the tuyere is regarded as an adiabatic environment, and the data required for calculating the theoretical combustion temperature in front of each tuyere of the blast furnace is collected through the data acquisition system, including but not limited to the flow and temperature of circulating gas, cold air flow, hot air temperature, hot air pressure, composition of injected circulating gas, blast furnace oxygen enrichment rate and oxygen enrichment amount, coke composition, composition of injected coal powder, coal powder injection amount, number of blast furnace tuyere and position of circulating gas injection tuyere, blast humidity. These data are stored in the database for use by the theoretical combustion temperature calculation system and the blast kinetic energy calculation system.

[0019] The theoretical combustion temperature calculation system obtains the theoretical combustion temperature of all tuyere front ends of the blast furnace. At this time, the temperature of the front end of the circulating gas injection will be lower than that of the tuyere without injection, and as the amount of circulating gas injection increases, the gap between the two will further increase. In order to solve this problem, under the premise of ensuring the total coal powder injection amount, the injection amount of the circulating gas injection tuyere is gradually reduced, and the coal powder injection amount of the non-injected tuyere is increased until the error between the two is within the specified range. If the calculated theoretical combustion temperature is lower than the specified threshold at this time, the operator is prompted that the theoretical combustion temperature is too low, and the blast furnace parameters that can increase the theoretical combustion temperature can be appropriately adjusted, such as increasing the oxygen enrichment rate. The calculation results are sent to the tuyere coal injection flow control system, through which the coal powder of each tuyere is accurately and dynamically controlled to achieve the purpose of temperature uniformity at the front ends of all tuyere.

[0020] When the theoretical combustion temperature meets the requirements, the kinetic energy of the blast at the front end of each tuyere is calculated, and the kinetic energy of the blast at each tuyere is compared to see if it is within the specified threshold range. If not, the size of the tuyere for spraying circulating gas and the tuyere for not spraying circulating gas is adjusted to optimize it.

[0021] The specific implementation process is as follows: the theoretical combustion temperature calculation system and the blast kinetic energy calculation system respectively obtain the theoretical combustion temperature and blast kinetic energy of all tuyere front ends of the blast furnace, and then the optimization algorithm is used to optimize the coal quantity and gas injection quantity of each tuyere branch pipe under the premise of ensuring the total coal injection quantity and the total circulating gas injection quantity, and then the coal quantity and gas injection quantity of each tuyere branch pipe are controlled by the tuyere coal injection flow automatic regulating valve and the tuyere gas injection flow automatic regulating valve. The optimization algorithm can be used to perform multi-objective optimization analysis on blast furnace parameters, reduce the frequency of blast furnace parameter adjustment, make the difference in theoretical combustion temperature at the front end of each tuyere less than the specified threshold, and thus ensure the uniformity of the initial gas flow temperature field; at the same time, make the difference in blast kinetic energy at the front end of each tuyere less than the specified threshold, and ensure the energy uniformity of the circumferential gas at the tuyere of the blast furnace.

[0022] In this application, optimization algorithms such as genetic algorithms can be used to perform multi-objective optimization analysis on blast furnace parameters and obtain the Pareto optimal solution.

[0023] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A method for optimizing the initial gas flow distribution of a top gas circulation blast furnace, characterized in that: The following steps are involved: The whirlpool area in front of the tuyere is regarded as an adiabatic environment; the data required for calculating the theoretical combustion temperature in front of each tuyere of the blast furnace is collected through the data acquisition system, and stored in the database for use by the theoretical combustion temperature calculation system and the blast kinetic energy calculation system; The theoretical combustion temperature and blast kinetic energy of all tuyere front ends of the blast furnace are obtained respectively by the theoretical combustion temperature calculation system and the blast kinetic energy calculation system. Then, the coal amount and gas injection amount of each tuyere branch are optimized and solved under the premise of ensuring the total coal injection amount and the total circulating gas injection amount through the optimization algorithm. Then, the coal amount and gas injection amount of each tuyere branch are controlled through the tuyere coal injection flow automatic regulating valve and the tuyere gas injection flow automatic regulating valve.

2. The method for optimizing the initial gas flow distribution of a blast furnace with top gas circulation according to claim 1, characterized in that: The data required for calculating the theoretical combustion temperature in front of each tuyere of the blast furnace include but are not limited to the flow and temperature of the circulating gas, the cold air flow, the hot air temperature, the hot air pressure, the composition of the injected circulating gas, the oxygen enrichment rate and amount of the blast furnace, the coke composition, the composition of the injected coal powder, the coal powder injection amount, the number of blast furnace tuyere and the injection tuyere position and blast humidity of the circulating gas.

3. The method for optimizing the initial gas flow distribution of a top gas circulation blast furnace according to claim 1, characterized in that: The optimization algorithm is a genetic algorithm.

4. The method for optimizing the initial gas flow distribution of a blast furnace with top gas circulation according to claim 1, characterized in that: The method for controlling the coal amount of each tuyere branch pipe is: on the premise of ensuring the total coal powder injection amount, gradually reduce the injection amount of the circulating gas tuyere, and increase the coal powder injection amount of the non-injected tuyere, until the error between the two is within the specified range.

5. The method for optimizing the initial gas flow distribution of a blast furnace with top gas circulation according to claim 1, characterized in that: The method for controlling the gas injection amount of each air outlet branch pipe is: when the theoretical combustion temperature meets the demand, calculate the blast kinetic energy at the front end of each air outlet, and compare whether the current blast kinetic energy of each air outlet is within the specified threshold range. If not, optimize it by adjusting the size of the air outlet that sprays circulating gas and the air outlet that does not spray circulating gas.

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