Research And Application Of Decoking Additive For Burning Xingjiang Zhundong High Alkali Coal Boiler

Xinjiang Xinte Energy Co.,Ltd.is located in the edge of Junggar basin,Xinjiang.Most of the coal we used in the existing thermal power plant of the company comes from "Zhundong coal" produced by the South Mine of Xinjiang Tianchi energy company,a subsidiary company of TBEA.It is a kind of high alkali coal with coking characteristics.In actual operation,the power plant has the problem that the boiler is forced to stop due to coking and pipeline corrosion It is important to study the basic mechanism of slagging,fouling and ash deposition of Zhundong coal,developing anti coking additives that can prevent boiler coking,mix them into raw coal to prevent boiler coking in the process of combustion.By developing the decoking agent,the original coking boiler can quickly decoking,and ensure long-term stable operation of boiler through prevention and post treatment.It’s theoretically significant and practically valueable.In this dissertation,the quality of Zhundong coal is analyzed and compared with the common coal types in China,the relevant characteristics of Zhundong high alkali coal are mastered.Through the ternary phase diagram analysis,the three substances with high content of silica,calcium oxide and aluminum oxide in Zhundong high alkali coal are analyzed.Using equilibrium module of factsage,the liquid phase temperature of coal ash is calculated.Based on the analysis of the performance of coal ash at different temperatures,the relationship between the ash melting point and the element content and chemical composition of the ash samples at different ash making temperatures,as well as the ash deposition characteristics in different particle size range are obtained.The factors influencing the physical properties and coking index of ash components,the effects of water,basic oxide,acid oxide and sulfur oxide on the coking of each section of flue gas were studied,which provided basic research basis for the selection of high-efficiency additives.Quadrant method was used to screen various elements,and the formula of powder additive was finally determined.Coking and smoke corrosion tests were carried out on the national combustion test platform of Harbin boiler plant for 30 consecutive days.In addition,tests were carried out in 350 MW Power Plant Boiler of Xinte Energy Co.,Ltd.to verify the application effect of the developed anti coking additive.At the same time,the anti coking agent was extended to the150 MW power plant boiler of Xinjiang Zhonghe Co.,Ltd.,a subsidiary of TBEA group,for trial use.Through the test,the anti coking additive can effectively inhibit the coking phenomenon in the combustion process of Zhundong high alkali coal.Basedon the previous research,the current decoking agent was analyzed and optimized,and different proportion of micro explosive high-efficiency decoking agent was mixed.The test was carried out on the power plant boiler to select the best proportion for trial use.At the same time,the development and use of micro explosive high-efficiency decoking agent was realized in combination with the decoking agent addition scheme.