Optimal control method for 300MW unit to effectively stabilize temperature of main steam

Abstract

The invention relates to an optimal control method for a 300MW unit to effectively stabilize temperature of main steam. The method includes the steps that firstly, difference value calculation is performed on the temperature of the main steam and a set temperature value of the main steam to obtain a difference value A, and TI-T2=A, wherein T1 is the temperature of the main steam, and T2 is the set temperature value of the main steam; secondly, the function relationship B=F(A) between the difference value A and flow B of desuperheating water is determined, the determining method of the function relationship includes the step that the accumulation amount and the transient time of the flow of the desuperheating water needed by the 300MW unit under certain loads are specifically recorded; thirdly, the relationship between the flow B of the desuperheating water and an opening degree C of an adjusting valve of the desuperheating water is determined; fourthly, the difference value A, the flow B of the desuperheating water, a difference P3 between pressure of the desuperheating water and pressure of superheating steam, and the opening degree C of the adjusting valve correspond to one another one to one so that optimal control over the desuperheating water can be achieved. According to the method, the adjusting quality and the energy utilizing rate are improved, the effect is obvious, and the method can be applied to various desuperheating control technologies and is wide in application market.

Description

technical field [0001] The invention belongs to the technical field of thermal automatic control, in particular to an optimal control method for effectively stabilizing the main steam temperature of a 300MW unit. Background technique [0002] Boiler superheated steam temperature is one of the most important parameters affecting the safety and economy of the boiler production process. Excessive superheated steam temperature will lead to excessive creep expansion of metal temperature, which will reduce the life of the pipeline. Frequent overheating can lead to overheating of the superheater pipeline squib. If the superheated steam temperature is too low, the thermal efficiency of the whole plant will be reduced. Generally, the thermal efficiency of the superheater will decrease by 1% for every 5-10°C reduction in the steam temperature of the superheater. Therefore, it is required to control the superheated steam temperature not to exceed -10~+5℃ of the rated value (given valu...

AI Technical Summary

Problems solved by technology

On the basis of the three necessary conditions, if PID regulation is used, it is easy to produce integral saturation, easy overshoot and other disadvantages. At present, there is a lack of a particularly effective method to control the main steam temperature.

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