神木烟煤燃烧时NO_x生成特性的试验研究

NO_x Formation Characteristics During Combustion of Shenmu Bituminous Coal

在一维热态试验炉上,采用双调风旋流燃烧器对神木烟煤进行了燃烧试验,研究了不同因素对NOx生成规律的影响.结果表明:随着一次风率f1的提高,NOx排放浓度先降低后上升,而煤粉燃尽率提高;当外二次当量风旋流强度Ωdl=0.87时,煤粉的燃尽率最高,而当Ωdl=1.08时,NOx排放浓度最低;降低外、内二次风风量比ε有利于煤粉的燃尽,当ε=3时,NOx排放浓度最低;当过量空气系数α=1.3时,煤粉的燃烧状况最好;抑制NOx排放的最佳煤粉粒径为20.77μm,煤粉的燃尽率随粒径的减小而提高.

Factors influencing the law of NOx formation during combustion of Shenmu bituminous coal were studied in a one-dimensional hot-state furnace with a dual-channel swirl burner. Results show that with the rise of primary air flow rate f1, NOx emission concentration reduces at first and then increases, while the burn-out rate of coal rises all along. Highest burn-out rate shall be obtained when the swirling intensity of outer secondary air Ωd1 is 0. 87, while lowest NOx emission concentration gained at Ωd1 = 1.08. The burnout rate can be improved by lowering the volume ratio ε of outer secondary air to inner secondary air, and lowest NOx emission concentration would be obtained at ε= 3. Optimum combustion performance shall be reached for an excess air ratio α= 1.3. For the purpose of reducing NOx emission, the optimum particle size is 20.77μm, and the burn-out rate of coal rises with the reduction of particle sizes.