Burning Quasi-east High Alkali Coal Critical Boiler Control Technology Research

Xinjiang Xinte Energy Co.,Ltd.self-supplied thermal power plant(hereinafter referred to as self-supplied power plant)2×350MW supercritical direct current boiler power generation coal-fired coal-based coal,mixed with other wells for coal.The coal in the Zhundong tianchi moutmine area is a high-alkali coal,causing severe slagging on the heating surface of the boiler,and frequent defocusing,causing the slag machine to stop,And the boiler's forced shutdown,greatly limiting the development of the coal in coal-electric industry.It is planned to conduct detailed performance tests on coal quality,combustion characteristics,slagging characteristics,and staining characteristics by aligning the east coal sample,and find out the mechanism of high alkali metal coal slag contamination,and seek to weaken,prevent,and treat alkali metals.Effective measures for slagging,reasonable arrangement of boiler heating surface,in order to effectively solve the problem that Xinjiang Zhundong coal can not be widely burn used in power station boilers.This study firstly analyzes the coal quality characteristics of East Coal and the migration law of alkali metals and alkaline earth metals,and conducts laboratory analysis and research through semi-industrial tests and on-site actual furnace tests to explore low-temperature combustion,coal blending methods,and primary air pressure,oxygen,etc.Align the influence law of the combustion characteristics of the Dongmei Boiler.Secondly,there are 17 typical working conditions chosed.Based on different X factors,these 17 working contions are devided into three groups,namely Experiments on the effect of changing the primary air pressure and air distribution mode on the furnace temperature distribution(working conditions 1-6)?the effects of the opening of the damper and the mixing ratio on the temperature distribution of the furnace(working conditions 7-12)? the opening of the variable air door Test of NOx and blending ratio on NOX(working conditions 13-17).All the working conditions were erperimented under full load 350 MW.The results show that:(1)when the secondary air door opening is 50%,the average temperature of the furnace is the lowest,and it is estimated that the slagging amount is the smallest.(2)When the blending ratio is changed,the trend of the furnace temperature distribution is chaotic,and no obvious conclusion can be drawn.(3)When the opening degree of the secondary damper is in the range of 0 ? 50%,NOX decreases as the opening degree of the damper increases.When the opening degree of the damper is greater than 50%,the change trend is not obvious.(4)The NOX concentration increases withthe increase of the proportion of burning.Finally,the effects of the primary air pressure,the amount of operating oxygen,and the primary air rate on the blending ratio of east high alkali coal were examined through experiments.The results showed that:(1)Reducing the primary air pressure can effectively prevent the diffusion of the actual combustion tangent circle.Through a large amount of test data,when 10 k P'a to 11 k P'a is selected,the coal blending ratio of Zhundong Tianchi South Mine can be increased by about 10%.(2)When the oxygen content is 3.9%-4.5%,the temperature of the boiler outlet smoke reaches the lowest level.Below or above this oxygen content,the furnace outlet smoke temperature will rise significantly during the boiler combustion process.This parameter can increase the coal blending ratio of Zhundong Tianchi South Mine by about 10%.(3)The temperature of furnace smoke turn out to be the lowest when the ratio of primary air being about 28%-30%.Then the temperature of furnace smoke increases obviously wih the decreasing of primary air.This parameter can increase the coal blending ratio of Zhundong Tianchi South Mine by about 10%.Through the above control strategy can increase the proportion of Zhundong coal blending by about 90%.