Combustion system and combustion method for retarding slagging and contamination of high-alkali coal boiler for combustion

Abstract

The invention provides a combustion system for retarding slagging and contamination of a high-alkali coal boiler for combustion. An outlet of a dry type electric precipitator is connected with a circulating fan through a smoke recycling pipeline, a pipeline behind the circulating fan and a primary air pipeline are both connected with a recycling pipeline, an ash bin is connected with an ash conveyer, one end of a circulating-ash-containing smoke and air mixing pipeline is connected with the recycling pipeline and the ash conveyer, and the other end of the circulating-ash-containing smoke and air mixing pipeline. The invention also provides a combustion method for retarding slagging and contamination of high-alkali coal boiler for combustion, the mixed airflow of low-temperature circulating smoke, part of primary air and flying ash are sent into a hearth in a layered manner from side boiler walls at four corners of the boiler, and a protection gas film of a wall attaching stream is formed nearby the boiler wall, so that the recycling of smoke and flying ash can be realized. According to the system and the method, the adjustment of the combustion condition of coal dust is facilitated, and the adaptability of the boiler to the coals can be enhanced, so that contamination and slagging of the heat exchange surface of the hearth can be inhibited, the heat exchange capability is changed correspondingly, the smoke discharging loss is reduced, and the boiler efficiency is effectively improved.

Description

technical field [0001] The invention relates to the technical field of coal-fired boilers, in particular to a combustion system and method for slowing down slagging and contamination of high-alkali coal-fired boilers. Background technique [0002] Xinjiang is one of the areas with the largest and most concentrated reserves of high-volatility high-quality coal in my country, and is an important energy and power construction base in China. The Zhundong coalfield is also a super-large integrated coalfield that has been discovered in Xinjiang in recent years, with reserves reaching 390 billion tons. Due to Xinjiang's special geographical location and traffic conditions, it is unlikely that Zhundong coal will be transported abroad on a large scale, and the prospect of Zhundong coal being used in power stations for power generation is very broad. Some power plants in Xinjiang have begun to mix Zhundong coal, and some even try to burn Zhundong coal completely, and make correspondi...

AI Technical Summary

Problems solved by technology

After the dust is deposited on the heating surface, due to its low thermal conductivity, it is equivalent to adding an insulating layer between the flue gas and the heating surface, which will eventually lead to an increase in the exhaust gas temperature, reduce the boiler efficiency, and seriously affect the economical operation.

[0006] (2) The temperature of the flue gas at the outlet of the furnace rises, deteriorating the slagging of the superheater in the high temperature area, causing the superheater steam temperature to be high, endangering the superheater, and may lead to tube explosion in the long run

[0007] (3) Cause high temperature corrosion

[0008] (4) The heat transfer resistance increases, and it is difficult for the boiler to maintain full-load operation. Increasing the amount of coal input will cause a further increase in the outlet smoke temperature, and the ash and slag are more likely to dry up on the heating surface, forming a vicious circle

[0009] (5) When the large slag from the upper part of the combustion chamber falls, it falls into the water seal device at the bottom of the furnace. Under the impact of the hot coke slag, the water in the water seal device vaporizes, and a large amount of steam causes the combustion fluctuations in the furnace chamber or even extinguishes the fire, and may also be smashed Water-cooled wall tubes and cold ash hoppers, causing serious consequences of hydrogen explosion in the furnace chamber

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