SU1025730A1 - Method for controlling heating of blast furnace air heater unit - Google Patents

Abstract

THE METHOD FOR CONNECTING THE HEATED AIR HEATER UNIT OF THE DOMAIN FURNACE by heating, including heating and switching devices from the heating mode to the blast and vice versa, controlling the gas flow rate for heating and determining the amount of heat required for heating the air heater according to the expected heat load during the preceding period, differ by that. in order to reduce the loss of heating gas on the candles and improve the stabilization of the pressure in the gas network, when switching one unit of the unit from blowing to heat on another buffer air The heater sets the task to the gas flow controller by the difference between the total amount of heat required for heating the heater and the amount of heat absorbed by the nozzle in the buffer mode, taking into account the O) time remaining until the end of heating, and the gas consumption is controlled, while controlled gas consumption is 0.1-0.9 the total duration of the heating period of the air heater. to: l: Hell

Description

The invention relates to metallurgical production, mainly to blast furnace, and can be used to control the heating of a block of various types of stoves. A known method of controlling a group of stoves of a blast furnace, which allows to determine the amount of heat required for each stove taking into account the heat given off by heaters at the beginning and at the end of the period; closest to the proposed technical essence is the method of controlling the heater of the stoves blast furnace, which includes heating and switching the arparat from the heating mode to the blast and vice versa, controlling the gas flow rate for heating and determining the amount of heat required dimogo stoves for heating of the expected heat load thereafter blowing 2. In a known method determined by the desired gas flow rate in accordance with a change in flow rate and temperature of hot blast which is set and then support it during the entire period of heating stoves, i.e. take into account and compensate for the indignation in the heat work in the heaters through the channel of what is blowing. At the same time, they do not solve the problem of maintaining a balance between the consumption and production of heating gas. The resulting inconsistencies in the consumption and production of heating gas lead to the fact that, when there is excess production, the gas is burned on the candle-burners to burn excess gas, and if there is insufficient production of gas, the pressure drops and, accordingly, the gas consumption of consumers fluctuates. These fluctuations cause undesirable fluctuations in the thermal regime, which reduces the quality of products from heating consumers. gas. The purpose of the invention is to reduce the loss of heating gas on the candles and to improve the stabilization of pressure in. gas network. The goal is achieved according to the method of controlling the heating of the blast furnace heaters unit, which includes heating and switching devices from the heating mode to the blast and vice versa, controlling the gas flow rate for heating and determining the amount of heat required to heat the air heater according to the expected heat load in the subsequent period , when switching off, one unit of the unit with blowing for heating on the other air heater, which was in the buffer mode, sets the reference to the controller gas flow by the difference between the total amount of heat required to heat the heater and the amount of heat absorbed by the nozzle during the buffer mode, taking into account the time remaining until the end of heating, and the gas consumption is regulated, while the duration of the gas consumption is 0 , 1-0.9 the total duration of the heating period of the air heater. Thus, in the first part of the heating period, the gas flow to the heater is not regulated, since the regulator is in a fixed position. In the second part of the heating period, the gas flow is adjusted so as to inform the heater the total amount of heat needed during the heating period. This takes into account the expected heat load in the subsequent cooling period and the amount of heat that the stove has already received in the first part of the heating period. In the second (last) part of the heating period, any law of variation in the flow rate of heating gas per heater can be maintained, but the simplest in terms of implementation is a constant flow rate. The drawing shows graphs of changes in heating gas consumption for a block of three heaters (curve 1), for the first heater (curve 2), for the second heater (curve 3), for the third heater (curve 4). To implement the proposed method, it is necessary that each heater be equipped with a heating gas flow controller, a device that determines the amount of heat absorbed during the past heating time, a device that determines the task for the heating gas flow controller in the last regulated part of the heating period. Digital UVM combines the functions of these devices. At the same time, with the help of UVM, commands are also issued for the transition to the cracking of the flow of heating gas to the given air heater. It is possible to turn on the CCM and in the operator advisor mode. In the absence of UVM at the facility, the proposed method can be implemented using appropriate analogue devices. When controlling with the aid of the CCM in the mode Operator's adviser at the initial moment of time O h, the operator transfers the first air heater ic to blow to heat. The body regulating the gas flow (gas throttle) is placed in the open position where it is fixed by the brake of the actuator. The gas flow rate at the first air heater does not regulate gas flow (curve 2) from 68 thousand m / h at time O to 100 thousand, at time 0.1 h and then after oscillation it drops to 43 thousand, i.e. . varies in accordance with the fluctuation of the gas flow rate per unit (curve 1). The gas flow rate to the third air heater is equal to 62 thousand and is maintained with the help of the heating gas flow controller (curve C). At the moment of time of 1 h, the operator switches the third heater from heating to blowing, the second heater from blowing to heating. In this case, on the first air heater, the operator switches on the heating gas flow rate control and sets the target flow rate, the value of which was calculated and outputted by the booster pump. The task for gas flow is calculated from the heat balance for the operation of the heater, i.e. by the difference between the total amount of heat that must be given to the heating nozzle to blow in the subsequent period, and the amount of heat absorbed by the first heater without regulation. Simplified gas flow is defined as the difference between the total amount of gas needed for the entire heating period and the amount of gas assimilated in the absence of regulation. For the entire period of TiarpeBa, 108 thousand are needed for the first air heater. For the first part of the heating period, the first air inlet, in the absence of regulation, acquired 75 thousand meters of gas, therefore, for the second part of the heating period, a task is given to the heating gas flow controller equal to 33 thousand. If the duration of the second part of the heating period is not equal to one hour, then take into account the time when determining the task for the gas flow rate. On the second air heater, the gas flow rate is not controlled and it oscillates (curve 3) in accordance with the fluctuation of the gas flow rate per unit (curve 1) at the same time. With subsequent switching of the apparatuses (time points 2 hours, 3 hours, etc.), the techniques and operations of the method for controlling the heating of the air heater unit are repeated, but with other air heaters. The ratio between the duration of the regulated gas consumption mode and the total duration of heating depends on the number of heaters in the unit (in the drawing it is 0-, 5). The maximum number of apparatuses in the prospective development unit is Y. Therefore, depending on the number of heaters in the unit, the duration of the regulated mode of gas consumption is 0.1-0.9 of the total duration of the heating period. Analysis of the gas flow to the candles shows that the flow fluctuates significantly due to the periodic connection and disconnection of consumers and generators of heating gas. At the same time, there are several times during the day when gas is produced more than consumed and vice versa. With excessive generation of heating gas, it is burned on candles, which leads to its irretrievable loss of m. Reducing gas losses with. the excess of its production in the proposed method is achieved due to the lack of regulation of the gas flow in the first part of the heating period, i.e. due to the work of the air heater in the buffer mode. The capacity of the stove to accumulate excess heat is determined by the ratio between the average flow rate of heating gas required for heating to blow to a predetermined temperature and the maximum heat output of the stove. Air heaters of a blast furnace with a volume of 5000 m at a known operating mode can accumulate excess heat of 100 thousand meters of blast furnace gas.

The proposed method improves the stabilization of pressure during periods when insufficient gas is produced. The ability of air heaters to maintain pressure, in a gas network with insufficient gas generation, is determined by the difference between the average consumption of heating gas required for heating to blow to this temperature and the minimum thermal power of air heaters.

It has been established that with the known method of controlling the heating of air heaters, the annual losses of blast furnace gas in a blast furnace of 5000 mp average about 250000 thousand meters. The invention allows reducing the losses by 50, while obtaining an additional effect due to improved stabilization pressure from other consumers of blast furnace gas (coke oven batteries, heating furnaces and wells, etc.)

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Claims (1)

METHOD FOR MANAGING HEATING OF A BLOCK OF BLAST FURNACE AIR HEATERS, including heating and switching devices from the heating mode to blast and vice versa, regulating the gas flow to heating and determining the amount of heat required to heat the air heater according to the expected heat load during the subsequent blast period, The fact is that, in order to reduce the loss of heating gas on candles and improve the stabilization of pressure in the gas network, when switching one apparatus of the unit from blast to heating on another buffer air supply the remitter set the task to the gas flow regulator according to the difference between the total amount of heat required to heat the air heater and the amount of heat absorbed by the nozzle in the buffer mode, taking into account the time remaining until the end of heating, and carry out an adjustable gas consumption mode, while the duration of the adjustable gas consumption mode is 0.1-0.9 of the total duration of the heating period of the air heater.