车辆选择性催化还原系统固态还原剂分解特性

Decomposition characteristics of solid reductant of vehicle SCR system

通过理论分析、热重实验、平衡压实验,对比了碳酸氢铵、碳酸铵、氨基甲酸铵3种铵盐的氨含量、分解温度、分解速率等特性。得出以下结论:氨基甲酸铵的氨含量最高,碳酸铵次之,碳酸氢铵最小;氨基甲酸铵和碳酸铵在室温下就开始分解,碳酸氢铵加热到100℃时只分解了5.6%;氨基甲酸铵在低于90℃时比碳酸铵分解速率快,在相同时间和温度下,氨基甲酸铵能产生更多的氨气;碳酸铵和氨基甲酸铵的分解平衡压相当,两者都是SCR系统还原剂的优良来源,氨基甲酸铵优势更明显。

The ammonia content,decomposition temperature and decomposition rate of ammonium bicarbonate,ammonium carbonate and ammonium carbamate are investigated by theoretical analysis,Thermogravimetric Analysis（TGA）experiment and equilibrium pressure experiments.Results show that ammonium carbamate has the highest ammonia content,followed by ammonium carbonate,and ammonium bicarbonate has the lowest ammonia content.Ammonium carbonate and ammonium carbamate can decompose from room temperature,but when heated to 100 ℃ ammonium bicarbonate only decomposes 5.6%.When the temperature is below 90 ℃,the decomposition rate of ammonium carbamate is higher than that of ammonium carbonate.Under the same period and same temperature,ammonium carbamate produces more ammonia.The decomposition equilibrium pressures of ammonium carbonate and ammonium carbamate are similar;both are excellent candidates of reductant of Selective Catalytic Reduction（SCR）system,but ammonium carbamate has more obvious advantages.