Accurate control system for natural cooling and automatic cooling of boiler and method

Abstract

The invention provides an accurate control system for natural cooling and automatic cooling of a boiler and a method. The system comprises the boiler and a chimney; the bottom part of the chimney is provided with an ejector device; the ejector device is externally connected with compressed air through a compressed air pipeline; the compressed air pipeline is provided with a pipeline shut-off valveand a pipeline regulating valve; the boiler is equipped with a pressure transmitter; and the pressure transmitter is interlocked with the pipeline regulating valve, so that proportion integration differentiation (PID) regulating is performed on the opening of the pipeline regulating valve according to furnace negative pressure of the boiler. According to the system, the bottom part of the chimneyis provided with the ejector device, so that the system forms negative pressure at the position of the chimney under the condition of natural ventilation to overcome flow resistance of a flue duct; meanwhile, interlocking control is performed on the pipeline regulating valve and the furnace negative pressure, and closed-loop regulation can be performed on the negative pressure at the position ofthe chimney according to a cooling curve, and then, the temperature drop rate of the boiler is regulated, and thus, the problem that the cooling rate cannot be accurately controlled during rapid cooling of the boiler when the boiler is shut down, and during conventional natural ventilation cooling is effectively solved.

Description

Technical field [0001] The invention belongs to the technical field of gas / coal-fired power generation, and specifically relates to a natural cooling automatic cooling accurate control system and method for a boiler. Background technique [0002] In the field of gas / coal-fired power generation, after the boiler is burned, steam is generated by heat exchange between flue gas and water, and steam is used to drive the steam turbine to generate electricity. The boiler will undergo planned and unplanned shutdowns during normal production. Generally, , The boiler's planned / unplanned shutdown and cooling of the boiler are all realized 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 uses the self-generated ventilation head generated by the density difference between the flue gas in the chimney and the outside cold air to overco...

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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