Oxy-CFB燃烧及污染物排放特性

Coal Combustion Characteristics From an Oxy-CFB Combustor With Flue Gas Recycle

在50kW循环流化床试验装置上进行空气燃烧和氧/烟气循环燃烧实验,考察不同燃烧方式下煤燃烧和污染物排放特性。结果表明,氧切换过程中密相区温度由空气燃烧时的880℃降低到了O_2/CO_2燃烧时的810℃,但随着氧气浓度上升,密相区温度迅速恢复到了空气燃烧时的水平。O_2/CO_2燃烧方式下,烟气中CO_2浓度可达到93%(干基);Ca/S摩尔比为4时,脱硫效率是88.5%;氮氧化物的排放量是24 mg/MJ,比空气燃烧时的105 mg/MJ大大减少;CO的排放量比空气燃烧时略低。

A steady oxygen/flue gas recycle operation was carried out on a 50 kWt Oxy-CFB combustor, and the effect of atmosphere on coal combustion and pollutant emission characteristics were investigated. Results show that, for the same heat input, the dense bed temperature dropped from 880℃ to 810℃ after finishing air-oxy transition but increased quickly to the previous level as the oxygen concentration increased. The CO2 concentration can reach 93 vol% on a dry basis. The desulfurization efficiency under oxy-mode operation with Ca/S molar ratio of 4 was 88.5%. Tile NOχ emission was 24 mg/MJ in oxy-mode, which was much less than that in air mode, 105 mg/MJ. The CO emission in oxy-mode was also lower than that in air-mode.