The Research On Coal Adaptability Analysis Of 660MW Supercritical Opposed Firing Boiler When Burning

According to the energy situation at home and abroad in recent years, the fact that coals will be the main body of the energy supplies in our country will not change in the future for a long time. Currently,many boilers got series problem when burning like combustion instability, low combustion efficiency, slagging etc.,due to their burning coals were non-designed coals. Therefore, a research on large capacity supercritical boiler’s safety and economy, broaden it’s adaptability to coals when burning non-designed coals, has become an important research topic in the electric power industry.One power plant which is located in the suburb of Shaoyang, Hunan province,mainly burning coals of inferior anthracite coals blended with local bituminous coals, or blended with other provinces’bituminous coals. It’s hard to ensure that the boiler burning designed coal while running. In order to broaden the adaptability of the power plant’s boiler when burning non-design coals,20 single coals and 15 kinds of blended coals were selected based on the 660MW supercritical opposed firing boiler’s burning coals in the power plant. First of all, a series of routine experiments were taken on 35 selected coals included proximate,ultimate,heating value text and thermal analysis,to figure out coal properties and combustion characteristics of the coals,provide basic information for the further heat transfer calculation model. After that, a mathematical model of heat transfer calculation was established based on the design size and structure characteristics of the 660MW supercritical power plant boiler’s furnace.After made improvement and refinement for the former Soviet Union boiler thermal calculation standard,the furnace was set in reasonable partition and series of heat transfer calculation were made lined to the improved mathematical model. Through this new heat transfer calculation,we’ve figured out in the load conditions of 100%,75%,50% when burns different coals, the changes of gas temperature, and average heat intensity along with height in furnace.Combined with the coals’ properties and combustion characteristics, come to the conclusion that the optimal coals for the boiler under different loads.According to the results of the analysis above,9 coals which got a better adaptability were set to thermal test.Through the field test,verified the accuracy of the mathematical model, then combining the factors of measured combustion emissions and ash combustible content, made a comprehensive judgment of the coals’adaptability to the boiler when burning.Finally, the best coal schemes were obtained:the most suitable coals for boiler combustion were Wugang long Ping coal which calorific value is higher than18.5MJ/kg,9%<Vdaf≤ 19%,blended coal SS64 and Shaoyang Qilishan coal which calorific value are higher than21.0MJ/kg in the load conditions of 660MW,500MW and 330MW respectively.