A precise control system and method for boiler natural cooling and automatic cooling

Abstract

The invention provides a precise control system and method for boiler natural cooling and automatic temperature reduction. The system includes a boiler and a chimney. An injection device is provided at the bottom of the chimney. The cut-off valve and pipeline regulating valve are equipped with a pressure transmitter on the boiler, and the pressure transmitter is interlocked with the pipeline regulating valve, so that the opening of the pipeline regulating valve can be adjusted by PID according to the negative pressure of the boiler furnace. In this invention, by setting the injection device at the bottom of the chimney, the system can form a negative pressure at the chimney under the condition of natural ventilation to overcome the flow resistance of the smoke duct, and at the same time, the pipeline regulating valve and the negative pressure of the furnace are interlocked and controlled. According to the cooling curve, the negative pressure at the chimney can be closed-loop adjusted, and then the boiler temperature drop rate can be adjusted, which effectively solves the problem of rapid cooling and cooling of the boiler when the boiler is shut down, and the problem that the cooling rate cannot be accurately controlled by conventional natural ventilation cooling and cooling.

Description

technical field [0001] The invention belongs to the technical field of gas / coal-fired power generation, and in particular relates to a precise control system and method for natural cooling and automatic cooling of a boiler. Background technique [0002] In the field of gas / coal-fired power generation, after combustion, the boiler generates steam through the heat exchange between flue gas and water, and the steam is used to drive the steam turbine to generate electricity. During normal production, there will be planned and unplanned shutdowns of the boiler. , The planned / unplanned shutdown of the boiler and the shutdown and cooling of the boiler are all achieved by ventilation. [0003] Boiler ventilation is divided into two categories, one is called natural ventilation, and the other is called forced ventilation (also called mechanical ventilation). Natural ventilation is to use the self-generated ventilation pressure head generated by the density difference between the flu...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the existing problems of natural ventilation and mechanical ventilation used for cooling boilers, the present invention provides a precise control system for natural cooling and automatic cooling of boilers. By modifying the bottom of the chimney to increase the pressure head and overcome the resistance of dust collectors to meet the requirements of natural ventilation

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