钙及其赋存形态对煤热解过程中氮转化的影响

燃煤NO_x生成与煤中含氮物质的种类及其在热解、燃烧中的转化特性密切相关。利用酸洗—物理混合/溶液浸渍添加方法制备获得含不同赋存形态Ca的煤粉,在水平管式炉上研究了不同赋存形态Ca对煤热解过程中氮转化特性的影响。结果表明,无机形式存在的Ca会使热解后的焦氮含量升高,而有机形式存在的Ca倾向于降低热解后的焦氮含量。添加以Ca(OH)2为模型物质的无机含钙矿物会抑制煤热解过程中NH_3的生成。添加以醋酸钙为模型物质的外在或内在有机含钙矿物后,NH_3均降低而HCN生成量升高,表明有机含钙矿物会促进煤中氮向HCN的转化。与以外在矿物形式添加的醋酸钙相比,以内在矿物形式添加的醋酸钙对热解中氮转化行为的影响较小。 NOx roles as one of those important atmospheric pollutants and the formation of NOx during coal combustion is related to the occurrence of N in coal and their behavior in the pyrolysis and combustion process.Coal powder with Ca in different occurrence forms was prepared by physical mixing and impregnation,and effect of Ca in different occurrence forms on nitrogen conversion characteristics was researched during pyrolysis on a tube furnace.Results show that Ca in inorganic form can increase coke nitrogen content during pyrolysis,while Ca in organic form tends to decrease coke nitrogen content.The excluded type mineral Ca(OH)2 reduces the formaction of NH3.Adding calcium acetate,both in excluded and included type,reduce the formation of NH3 while improves the yield of HCN,which indicates that organic Ca would promote the partitioning of nitrogen in coal into HCN.What's more,the effects of calcium acetate in the excluded type is more remarkable than that in included the type