Early-warning system for preventing cold ash hopper area of power station boiler from detonation, and adjustment method

Abstract

The invention discloses an early-warning system for preventing a cold ash hopper area of a power station boiler from detonation, and an adjustment method, and belongs to the field of large power station boiler safety. The early-warning system for preventing the cold ash hopper area of the power station boiler from detonation comprises a main flue gas pipe, CO concentration probes, a CO concentration field treatment device, a DCS control device and a flue gas fan, wherein the CO concentration probes are arranged on the four walls of a cold ash hopper in the lower part of a boiler hearth and measure a CO concentration in the boiler; the CO concentration field treatment device collects the concentration signals of the CO concentration probes, and directly controls the opening degree of a fluegas adjustment valve through the DCS control device and according to a feedback signal after analysis for a concentration field; the flue gas fan increases the pressure of flue gas in a tail flue, and then inputs the flue gas into flue gas nozzles; and the flue gas nozzles are arranged in the cold ash hopper area in the form of a quadrilateral-wall contact circle, and the flue gas forms a contactcircle flow field in the cold ash hopper area via the flue gas nozzles. According to the early-warning system for preventing the cold ash hopper area of the power station boiler from detonation, andthe adjustment method, a dilution medium adopted is the flue gas, has an extremely low oxygen content, and is higher in inertia compared with air, so that the risk of CO explosion can be further lowered.

Description

technical field [0001] The invention belongs to the safety field of large-scale power station boilers, and in particular relates to an early warning system and an adjustment method for preventing deflagration in a cold ash hopper area of ​​a power station boiler. Background technique [0002] According to incomplete statistics, among the "non-stop" accidents of large-scale power plant boilers in China, cases caused by furnace deflagration account for about 20%. How to prevent furnace deflagration has become a topic of concern in the power industry in recent years, but due to various reasons Still no better solution. At present, the main difficulties are mainly reflected in: (1) At the present stage, the sources of coal types used by power plants are relatively wide, and the types of coal types change frequently, and even seriously deviate from the range of designed coal types and checked coal types, resulting in boilers remaining at the same level for a long time. (2) In or...

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Problems solved by technology

[0003] A large number of experimental studies and theoretical analysis show that the concentration of CO (strongly combustible reducing gas) in the local area of ​​the boiler furnace (mainly the cold ash hopper area at the lower part of the furnace) can reach more than 3000 μL / L under severe conditions, which already belongs to the explosion zone. When coke or sparks fall, it will cause an explosion, causing serious safety accidents

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