Start-up and stop control method of wet desulfurization system without bypass

Abstract

A start-stop control method of a bypass-free wet desulphurization system belongs to the technical field of wet desulfurization desulfurization system. An absorption tower slurry and original ash are preloaded for a startup process; a startup sequence is as below: successively putting an induced draft fan, a blower, an electrostatic precipitator, a demister flushing water pump and an oxidation air blower into operation; then igniting a boiler; and then starting an absorption tower slurry circulating pump, a desulfurization auxiliary system and SO2 removal rate adjustment. A stop process is as below: after flameout of the boiler, first stopping an absorption tower limestone slurry feed system, the blower and the induced draft fan; then releasing an absorption tower entrance accident spray system interlocking; and then stopping the absorption tower slurry circulating pump, a demister flushing system and the electrostatic precipitator. The startup and stop alternative control method for the desulfurization system and the boiler can reduce the dust and dirt entering into an absorption tower slurry pool, avoid influence of high temperature flue gas on the absorption tower, reduce discharge of the absorption tower slurry or waste amount to save the follow-up treatment costs, while effectively guaranteeing normal start and stop of the bypass-free wet desulfurization system.

Description

technical field [0001] The invention belongs to the technical field of wet desulfurization systems in thermal power plants, and in particular relates to a start-up and stop control method for a bypass-free wet desulfurization system suitable for the start-up and shutdown control of a thermal power plant. Background technique [0002] my country is a big coal-burning country, and coal accounts for 75% of the total primary energy consumption. In the near future, electricity will still be dominated by the construction of coal-fired power plants. With the continuous growth of coal consumption, the sulfur dioxide emitted by coal combustion is also increasing. The country with the largest sulfur dioxide emissions in the world, among which the sulfur dioxide emissions from coal-fired power plants have reached more than 50% of the total emissions. [0003] For a long time, under the guidance of the government's environmental protection policy, the thermal power industry has actively ...

AI Technical Summary

Problems solved by technology

[0005] At present, the desulfurization system without flue gas bypass that is gradually put into use is characterized by the fact that when the unit is started, normal operation and accident conditions, all the boiler flue gas is discharged into the chimney after passing through the desulfurization system, and there is a traditional start-stop control of the bypass desulfurization system The method is not suitable for the start-stop control requirements of the flue gas bypass desulfurization system; when the wet desulfurization system without bypass is started or shut down, if the control is not proper, it will lead to start-up failure or even send a safety accident, such as boiler flue gas temperature Or when the dust concentration exceeds the design value, accidents such as burning damage to the internal parts of the absorption tower and poisoning of the absorption slurry may occur. When the desulfurization system fails and needs to be shut down, there is no bypass to go, and the host must be shut down synchronously

Therefore, the operation status of the desulfurization system without bypass will have a great impact on the operation of the boiler, and the connection between the two will be closer. During the start-up and shutdown process, the boiler and the desulfurization system need to be closely connected with each other to ensure safe production and prevent environmental pollution. Accidents, the difficulty of start-stop control of the bypass-free desulfurization system also hinders the application and promotion of the bypass-free desulfurization system to a certain extent