A control method for coal-fired units considering the time-space distribution of heat storage

Abstract

The present invention proposes a coal-fired unit control method considering the time-space distribution of heat storage. In the actual operation process, when the load is increased, the temperature of the main steam is relatively low, and the temperature of the reheat steam is relatively high. The reason is that the temperature at the outlet of the economizer changes slowly due to the large amount of heat storage change, and the overshoot of the coal volume causes the problem of uneven heat matching between the main and reheat steam. In order to solve the above problems, the heat storage change of the economizer and the change of the heat transfer of the superheater in the water-cooled wall or the flue on the superheated side caused by the change of the unit reheat steam temperature adjustment are quotiented, and it is calculated with the reheat steam temperature adjustment Add the amount command to get the new value of the reheat steam temperature adjustment amount. The present invention compensates the delayed change heat of the economizer through the temperature adjustment amount of the reheater by the heat absorbed by the superheater in the water wall or the flue on the superheated side, and completes the coupling adjustment of the main and reheat steam temperatures, effectively improving the variable load Improve the quality of the steam temperature in the process and improve the economical operation of the unit.

Description

technical field [0001] The invention belongs to the technical field of thermal control in thermal power plants, and in particular relates to a control method for a coal-fired unit considering the time-space distribution of heat storage. Background technique [0002] Boiler heat storage is the main reason for the slow change of metal wall temperature. Considering the heat storage change distribution in the boiler is of great significance to the precise control of steam temperature. Due to the structural characteristics of the boiler itself, the heat storage of the economizer has a large and slow change, resulting in a slow change in the outlet temperature of the separator, which affects the control of the water-fuel ratio, and then seriously affects the control effect of the main and reheat steam temperature. Therefore, the heat storage change of the economizer is compensated by the heat absorption of the superheater in the water wall / superheating side flue through the adjus...

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Problems solved by technology

[0003] Aiming at the characteristics of uneven heat storage distribution in the boiler, combined with the actual power plant operation problems, the present invention starts from the essential difference between the transient characteristics and static characteristics of the boiler, and aims to find a method to fundamentally improve the quality of unit parameter control

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