溴添加对燃煤烟气汞形态转化的影响

在一维管式沉降炉燃烧试验装置上,以汞的氧化率为评价指标,进行了溴化物种类、添加浓度、添加方式等因素对燃煤烟气汞形态转化影响的实验研究.结果表明:溴对汞的氧化起促进作用,汞氧化率在一定的范围快速增加,超过此范围缓慢增加.不同的煤质,不同的溴添加物,这个范围是不同的;综合考虑添加成本,操作难易程度以及汞的氧化率,添加同浓度的溴化物时,汞的氧化率由低到高的排列顺序依次是:HBr炉后HBr炉前Ca Br2Na Br.在本实验条件下,汞的氧化效果最佳的条件是,褐煤中添加200mg/kg溴化钠,汞的氧化率约72%;亚烟煤添加1000mg/kg溴化钠,汞的氧化率约83%.

Impacts of bromine addition on mercury transformation in coal-fired flue gas

Impacts of bromide type, concentration, and addition mode on mercury oxidation in coal-fired flue gas from a drop-tube furnace was investigated. The experimental results indicated that bromine promoted mercury oxidation in coal-fired flue gas. The oxidation rate increased rapidly in a specific bromine concentration range and slowed when the concentration exceeded the range. This optimal range varied by coal quality and bromide type. Regarding the cost, operability and effectiveness of the bromine addition mode, the effectiveness followed the sequence post-combustion HBr injection < pre-combustion HBr injection < CaBr2 addition to coal < NaBr addition to coal. The highest mercury oxidation rate for lignite (72%) was obtained by adding NaBr at 200mg/kg, and the highest rate for sub- bituminous coal (83%) was obtained by adding NaBr at 1000mg/kg.