An intelligent system and method for preventing combustible gas deflagration at the furnace bottom

Abstract

The invention discloses an intelligent system for preventing boiler bottom combustible gas from detonating and a method. The system comprises a hot air conveying and distributing subsystem, a boiler bottom atmosphere measuring subsystem and a control system; the hot air conveying and distributing subsystem conveys hot air taken from a primary hot air mother tube and a secondary hot air tank to spray ports in slopes of a dry bottom hopper at the boiler bottom; the boiler bottom atmosphere measuring subsystem is arranged at the boiler bottom and is used for sampling boiler ash and smoke and measuring the accumulation concentration of the boiler bottom combustible gas; the control system is used for controlling all hot air control baffles of the hot air conveying and distributing subsystem according to the combustible gas concentration measured by a measuring device and the boiler operation state and eliminating the accumulated combustible gas until the combustible gas concentration of each measuring point is lower than a set value, and the boiler bottom combustible gas is prevented from detonating. With the system and the method, accumulation of the boiler bottom combustible gas is eliminated in a fixed-point manner, the boiler bottom combustible gas is effectively prevented from detonating, and no negative effects are caused to the combustion condition in the boiler and the economic efficiency of boiler operation.

Description

technical field [0001] The invention relates to an intelligent system and method for preventing combustible gas deflagration at the furnace bottom. Background technique [0002] In my country's thermal power plants, pulverized coal boilers are widely used due to their high combustion efficiency and low operation and maintenance costs. At the same time, with the long-term emission standards of thermal power generation, in order to reduce the emission of nitrogen oxides, The most effective method for pulverized coal boilers is to use low-nitrogen combustion. At present, most power plants use air staged combustion and low-oxygen combustion to achieve low-nitrogen combustion. However, this combustion method leads to oxygen-deficient combustion in the main combustion area. For boilers adopting wet slagging method, this combustion method makes the accumulation of combustible gas in the bottom of the boiler, that is, the area of ​​the cold ash hopper more serious (for boilers adoptin...

AI Technical Summary

Problems solved by technology

However, this patent does not clarify whether the injected air is hot air or cold air. If it is cold air, it will cause the center of the boiler flame to move upward, the amount of desuperheating water in the superheater and reheater will increase, and even the temperature of the tube wall will exceed the temperature. The rise of the smoke temperature will have a great negative impact on the economy and safety of the boiler; even if the injected air is hot air, it is calculated as 7% of the required air. For a boiler with a 300MW unit, the total air volume is 1200 tons It is estimated that the amount of injected air is 84 tons, and the amount of injected air is relatively large, which will obviously affect the distribution of air volume in the main burner area and the burnout area, and will have an impact on the NOx generation of the boiler and fly ash combustibles. The result may be The carbon content of the slag is reduced, but the carbon content of the fly ash and the NOx concentration are increased, and the comprehensive evaluation of its economy may not be worth the candle

This patent does not explain how to control the amount of air injected into the furnace, and does not realize automatic control. Another point is that the accumulation of combustible gas at the bottom of the furnace is mostly local accumulation. When all the nozzles are sprayed with air, the actual effect will be reduced. Gas accumulation, but too much air injected will affect the combustion and economy of the furnace

[0005] Through the above analysis, it can be seen that the accumulation and deflagration of combustible gas at the bottom of the boiler is unpredictable, and there is no effective operation method to prevent it, which has seriously affected the safety and stability of the boiler. method of gas accumulation

Images