煤矸石与半焦富氧混烧特性及污染物排放特性研究

Study on the oxy-fuel co-combustion of coal gangue and semicoke and the pollutants emission characteristics

利用热重分析仪和管式炉实验,研究了煤矸石与半焦的富氧混烧特性,考察了半焦混烧比例、O_(2)含量和反应温度对燃烧特性和污染物排放特性的影响。结果表明,混烧半焦和提高O_(2)含量均可显著改善混合燃料的燃烧性能,当半焦混烧比例为75%时,着火和燃尽指数最高。随半焦混烧比例增大,CO和SO_(2)转化率均逐渐降低。提高反应温度,CO转化率降低,SO_(2)转化率增大,NO转化率呈现先升高然后降低或缓慢增加趋势。反应温度为900℃时,混烧半焦可降低燃烧过程的NO排放量。其余反应温度下,混烧半焦会增大NO转化率。随O_(2)含量升高,混合燃料富氧燃烧过程的CO转化率降低,NO转化率升高,SO_(2)峰值释放量和转化率呈先降低后升高的趋势。当O_(2)体积分数为20%时,SO_(2)转化率最低。

The oxy-fuel co-combustion of coal gangue and semicoke and the pollutants emission characteristics were studied by thermogravimetric analyzer and tube furnace experiments.The effects of semicoke blending ratios,O_(2) concentration and temperature were investigated.The results showed that the combustion performance of blended fuel could be improved with the addition of semicoke and the increase of O_(2) concentration.The maximum ignition and burnout index were obtained when semicoke blending ratio was 75%.The X_(co) and x_(so2) gradually decreased with the increase of semicoke blending ratios.As the increase of temperature,the X_(co) decreased,x_(so2) increased while X_(No) firstly increased then decreased or slowly grew.The NO emission could be reduced with the addition of semicoke when the temperature was 900 ℃.However,it would aggravate NO emision at other temperatures.With the increase of O_(2) concentration,the X_(co) decreased,X_(NO) increased while x_(so2) firstly decreased and then increased.The minimum x_(so2) was obtained when O_(2) concentration was 20%.