A BFG Boiler Negative Pressure Optimization Control Method

Abstract

The invention provides a negative pressure optimal control method of a BFG boiler. The negative pressure optimal control method comprises the following steps that a hearth negative pressure setting value is subtracted from a hearth negative pressure measuring value to obtain a hearth negative pressure deviation signal; the hearth negative pressure deviation signal is inputted into a PI controller,the PI controller calculates a PI operation output quantity; an air supply quantity corrected by oxygen amount is multiplied by feedforward gain to obtain an air supply quantity feedforward calculation output quantity; pressure of the blast furnace gas main pipe is multiplied by the feedforward gain to obtain a coal gas quantity feed-forward operation output quantity; the PI operation output quantity is added with the air supply quantity feedforward calculation output quantity and the coal gas quantity feed-forward operation output quantity, and a variable-frequency input quantity of an induced draft fan is obtained; and the output of the induced draft fan is adjusted through the variable-frequency input quantity of the induced draft fan, and then the negative pressure of the hearth is adjusted. According to the negative pressure optimal control method of the BFG boiler, not only can induced wind frequency conversion control be used for carrying out continuous deviation adjustment onthe negative pressure of the hearth in response to an air volume change, also the change of the blast furnace gas quantity can be quickly responded, so that the pressure of the hearth is guaranteed tobe micro-negative pressure, the combustion of the boiler is stabilized, the internal disturbance of the system is inhibited, and the running stability of a generator set is improved.

Description

technical field [0001] The invention belongs to the technical field of thermal automatic control, and in particular relates to a negative pressure optimization control method of a BFG (Blast Furnace Gas) boiler. Background technique [0002] During the steelmaking process of steel mills, a large amount of blast furnace gas is produced, and the supporting BFG boiler fully burns the blast furnace gas and converts it into electrical energy, realizing the secondary utilization of resources. The boiler of this type of power station is different from the conventional coal-fired boiler. It is characterized by using the waste gas of the iron and steel plant as fuel, and there is no fuel pretreatment process. The flue gas after combustion can be directly discharged into the atmosphere without the need for flue gas treatment. . [0003] For conventional coal-fired power plants, the load adjustment is generally based on the electrical load to determine the load of the steam turbine, t...

AI Technical Summary

Problems solved by technology

Since the blast furnace gas produced in the steelmaking process continuously disturbs the combustion of the BFG boiler, the furnace pressure will still fluctuate from -200Pa to 200Pa under the condition of automatic negative pressure input, which is not conducive to the safe and stable operation of the boiler main equipment

There are many unsafe factors in the positive pressure combustion of the furnace; too low negative pressure combustion will cause part of the gas to enter the flue without complete combustion, and at the same time bring heat into the flue (this will accelerate the damage of the induced draft fan and cause heat loss in advance )

In addition, large fluctuations in negative pressure will cause continuous system internal disturbances in the overheated air temperature, resulting in frequent actions of the desuperheating water control valve and shortening the service life of the desuperheating water control valve

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