响应曲面法评价与优化混煤富氧燃烧特性

Evaluation and Optimization of Oxygen Enriched Combustion Characteristics of Blended Coals by Response Surface Methodology

研究了小龙潭褐煤、富源烟煤和昭通褐煤混煤的燃烧特性,对比了不同氧气浓度、不同升温速率下煤样的热解及燃烧特性,采用响应曲面法优化软件对氧气浓度、升温速率及煤粉配比进行优化.结果表明,富氧燃烧时,煤样着火温度和燃尽温度降低,燃烧时间缩短;氧气浓度高于30%(?)后,煤粉燃烧特性参数变化趋于平缓,实际应用中氧气浓度应控制在30%左右;煤粉燃烧后段活化能较高,煤样活化能、指前因子随氧气浓度增大而增大;升温速率增大,煤样的着火温度和燃尽温度升高,煤粉燃烧时间延长,稳定性、燃烧性变差.氧气浓度越高,煤样燃烧性能越好,设置可燃性指数和燃烧特性指数最大,燃尽温度和投资成本最小,小龙潭褐煤:昭通褐煤:富源烟煤质量比为100:55.07:1时优化的4个评价指标最好,可燃性指数为43.56×10-7,燃烧特性指数为4.27×10-10,燃尽温度为680.01℃,成本为252.49$/t.

The essay studies on the combustion of blended samples of Xiaolongtan lignite（X）, Fuyuan bituminous coal（F） of and Zhaotong lignite（Z） and their combustion characteristics were analyzed by comparing the results of thermogravimetric experiments with different oxygen concentrations and heating rates. The oxygen concentration, heating rate and mass ratio of mixture coal were optimized by applying the optimization software of response surface Design-Expert 8.0.6. The results showed that the temperature of coal ignition and burnout decreased and the combustion time was shorted when oxygen was enriched. When the concentration of oxygen reached the point of 30%（？） the variation of combustion characteristic parameters was minim, so the oxygen concentration in practical application should be controlled around 30%. The activation energy was higher at the later period of pulverized coal combustion, and the activation energy and the pre-exponential factor was increased with the increase of oxygen concentration. Besides, when heating rate grew, the temperature of coal ignition and burnout temperature increased, the burning time was prolonged, while the stability and combustibility was worse. It showed that the coal combustibility improved with the increase of oxygen concentration. The value range of each factor was designed in Criteria of Design-Expert 8.0.6. Set the combustible index and the combustion characteristic index the maximum value and set burnout temperature and investment cost the minimum value, when the mass ratio of Xiaolongtan lignite：Zhaotong lignite：Fuyuan bituminous coal was 100：55.07：1, the four evaluating indicators were relatively optimum, combustibility index was 43.56×10-7, combustion characteristic index was 4.27×10-10, burnout temperature was 680.01 ℃, cost was 252.49￥/t.