麦秆和煤热解过程中N-S-Cl的释放特性

Release characteristics of N/S/Cl species during pyrolysis of biomass and coal

利用TG-MS联用技术研究麦秆和烟煤在线性升温热解过程中含N,S和Cl的气相产物的析出过程,得出麦秆和煤热解过程中N-S-Cl组分的释放规律,并对不同温度下的残余焦样进行XRD分析,以验证气相组分的析出规律。试验结果表明:麦秆和煤中含N组分、含S组分和含Cl组分分别从200℃和350℃以上开始析出,分别在350,475℃析出速率最大。麦秆和煤热解过程中的含N组分主要是NH3和HNCO,麦秆释放的含N产物中的NH3量最大,其次为HNCO;麦秆热解过程中含S组分仅检测到微量的COS,而烟煤热解则仅检测到H2S和SO2,其中H2S的生成温度为500～600℃,SO2的释放则分为3个阶段(300～500,500～600,1 200～1 450℃)。麦秆和煤热解过程中的主要含Cl组分为HCl和微量的Cl2,同时在800℃以上时麦秆中的KCl全部析出。

The combined TG-MS techniques were used to analyze the emission of gaseous species containing nitrogen,sulfur and chlorine during the pyrolysis process of straw and bituminous coal.The residual chars obtained at different heating temperature in the fixed bed were investigated with XRD to provide supplementary information of emission of gaseous species.The results show that the release of the gaseous species containing nitrogen,sulfur and chlorine,started from about 200 ℃ from straw and 350 ℃ from coal,with a peak mass loss at about 325 ℃ and 450 ℃ respectively.NH3 and HNCO are the primary nitrogen species for both straw and coal.For the pyrolysis of straw,the content of NH3 is much higher than that of coal pyrolysis.COS is the major sulfur species during the pyrolysis of straw.During coal pyrolysis the sulfur species were only H2S and SO2.H2S is mainly formed between 500 ℃ and 600 ℃ and SO2 is released from coal pyrolysis in three stages（300-500,500-600 and 1 200-1 450 ℃）.The chloric species from the pyrolysis of both straw and coal are HCl and little Cl2.There is a temperature of around 800 ℃,for chlorine to be able to remain in the biomass.