Combustion Device Design And Combustion Characteristics Research Of Blue-Coal

Blue-coal is a product obtained from low-temperature carbonization of high quality Jurassic non-caking coal or weak-caking coal,which is widely used in metallurgy,chemical industry and other fields.However,due to the poor combustion performance,it is difficult for blue-coal to be used in industrial boilers.Compared with the common fuels of industrial coal-fired boilers,the blue-coal has a significant advantage on price,and the amount of pollutants generated in the combustion process is relatively low.Therefore,exploring the application of blue-coal in industrial boilers will help alleviate the increasingly serious problems of energy shortages and environmental pollution,and meanwhile reduce the operating costs of industrial boilers to some extent.Firstly,the differences of combustion characteristics between Shenmu bituminous coal,Datong bituminous coal,Guizhou anthracite and blue-coal were studied by the method of thermal analysis,and the major reasons leading to these differences were analyzed.Besides,different doses of manganese dioxide or sodium citrate were added into blue-coal samples and the effects of two kinds of combustion adjuvants on combustion characteristics of blue-coal were investigated.When a small amount of MnO₂ is incorporated into blue-coal samples,the combustion performance of blue-coal was significantly improved,while increasing the proportion of MnO₂ would greatly reduce the burning rate,and thus have a very unfavorable effect on combustion process.When using sodium citrate as combustion adjuvant,with the increase of the sodium citrate proportion,the combustion characteristic temperatures and activation energy decrease,and the effect of sodium citrate on combustion characteristics of blue-coal is better than that of MnO₂.The thermal analysis experiments were preformed on blue-coal samples with different particle size ranges,and as the particle size decreases,the ignition temperature of blue-coal decreases,the burning rate increases,and the activation energy decreases,indicating that decreasing the particle size of blue will help to improve its combustion performance.In addition,the effect of heating rate on thermal analysis results was studied.It was found that the faster the temperature rises,the more obvious the thermal hysteresis is,resulting in a greater experimental result error.Thermal analysis experiments at a heating rate of20?/min may give relatively accurate results.A test system based on circulating fluidized bed combustion technology was established under laboratory conditions.The feeding rate of fuel,the temperature and flow rate of primary air can be adjusted by the control system to simulate the combustion environment in industrial boilers.According to the monitoring records of temperatures,pressures and other data in different areas of the test system,the combustion process of the fuels can be analyzed,which is conducive to determine the optimal combustion conditions and operating conditions for the fuel,achieving a higher combustion efficiency and exhaust gas purification rate.