聚丙烯酰胺热分解与脱硝性能研究

Study on thermal decomposition and denitration performance of polyacrylamide

选择三种不同类型聚丙烯酰胺作为高分子脱硝剂,通过热重分析、程序升温-质谱分析了三种不同类型的聚丙烯酰胺升温分解过程,同时考察其高温烟气脱硝性能。结果表明,三种不同的聚丙烯酰胺最终失重率大小为:阳离子型CPAM>非离子型NPAM>阴离子型APAM。通过程序升温-质谱检测显示,三种聚丙烯酰胺在升温分解过程中均首先发生端基酰胺基分解产生氨气,然后发生主链断裂。三种聚丙烯酰胺的热分解生成氨的表观活化能分别为CPAM 169.72 kJ/mol,APAM 246.58 kJ/mol和NPAM 210.18 kJ/mol。三种聚丙烯酰胺脱硝性能为NPAM>CPAM>APAM。脱硝活性与PAM分解产氨的速率和产氨量有关,产氨速率较慢、产氨量较高的NPAM脱硝活性较高,产氨量较低的APAM活性较差。优良的高分子脱硝剂需要较好的热稳定性以及更多分解氨的量。

Three different types of polyacrylamides were selected as polymer denitration agents,and the pyrolysis process of PAM was analyzed by thermogravimetric analysis(TG)and temperature-programmed mass spectrometry(TP-MS).And the denitration performance of polymer denitration agents was also evaluated at high-temperature.The results showed that the final weight loss rate of three kinds of polyacrylamide was:CPAM>NPAM>APAM.Through TP-MS detection,it was found that all three types of polyacrylamides undergo terminal amide group decomposition to produce ammonia gas during the temperature rise decomposition process,firstly,and then the main chain was broken.The apparent activation energy of ammonia generated by thermal decomposition of three types of polyacrylamides are CPAM 169.72 kJ/mol,APAM 246.58 kJ/mol and NPAM 210.18 kJ/mol,respectively.The denitrification performance of three types of polyacrylamides is NPAM>CPAM>APAM.The denitrification activity is related to the rate and amount of ammonia produced by PAM decomposition.NPAM with slower ammonia production rate and higher ammonia production exhibits higher denitrification activity,while APAM with lower ammonia production has poorer activity.Excellent polymer denitration agents require good thermal stability and a greater amount of ammonia decomposition.