城市下水污泥和煤/LPG在循环流化床上的混烧试验研究

在高6000 mm、直径300mm的循环流化床上进行了含水率为79％的湿污泥与煤／石油液化气(LPG)的混烧试验。试验结果表明:无论用煤还是LPG作为辅助燃料,试验都能在设定的工况条件下稳定运行;向炉内加入石灰石的量达到钙硫摩尔比为3．4∶1时,二氧化硫和氯化氢的排放达标,脱硫效率和脱氯效率分别为75％和94％;在试验中, 烟气中NOx排放、烟气中汞含量和二恶英类排放都不超标;试验产生的飞灰含碳量低,飞灰中痕量元素的浸出毒性不超标;计算表明,如果利用余热干燥污泥和预热空气可有效地减少辅助燃料的消耗量。

CO-COMBUSTION OF WET SEWAGE SLUDGE AND COAL/LPG IN A PILOT SCALE CIRCULATING FLUIDIZED BED

Experiments on co-combustion of wet sewage sludge with moisture content of as high as 79% and coal/liquefied petroleum gas (LPG) were investigated in a pilot scale circulating fluidized bed combustor of 300 mm in diameter and 6000 mm in height. The results showed that the experiments were smooth whether the auxiliary fuel was coal or LPG. Although nitrogen content in sewage sludge was high, the NOx emissions in all cases met Chinese current environmental regulation. In the desulfurization test with limestone at the molar ratio of Ca/S of 3.4, SO2 and HC1 emissions were below the limitation and the efficiencies of desulfurization and dechlorination were 75% and 94%, respectively. Hg and dioxins emissions do not exceed the regulation limitation. The carbon contents in fly ash were low and the leached concentrations of the trace elements of the fly ash were below the regulation limitation. The ratio of auxiliary fuel can be decreased by drying sludge and preheating air through recovering the heat of exhaust gas.