氢氩等离子体热解煤焦油制乙炔结焦机理分析

Coking mechanism during thermal plasma pyrolysis of coal tar to acetylene

氢氩等离子体热解煤焦油在反应过程中产生的结焦物,主要是由气态碳气相沉积和煤焦油缩聚反应产生的。分析表明,结焦物在不同的操作条件下性质具有较大差异,结焦物中的各元素含量和平均粒径也会随着反应条件的变化而出现差异,碳纳米纤维状的结焦物主要在低氢气浓度和低输入比焓条件下产生;片状和球状结焦物主要在高氢气浓度和高输入比焓下产生;结焦物的石墨化程度随着反应气氛中氢气浓度增加而减弱。煤焦油反应过程中的转化程度越高结焦越严重,控制反应温度和提高气相反应中的氢浓度越可以控制反应过程中的结焦。

The coking products are generated by vapor deposition of gaseous carbon and coal tar condensation reactions during the reaction process of thermal plasma pyrolysis of coal tar to a- cetylene. The analysis results indicated that coking products generated at different conditions which showed various characteristics, structures and average particle size, such as coking materi- als of carbon nanofibers were generated at low hydrogen concentration and low coal tar specific enthalpyl plate-shaped and globular-shaped particles were generated at high hydrogen concentra- tion and high coal tar specific enthalpy. The graphitization degree of coking materials decreased at high hydrogen concentration in the plasma working gas. The higher coal tar conversion results in the higher coking degrees. The higher coal tar conversion resulted in the higher coking degrees. The cokes could be reduced by adjusting suitable reaction temperature and increasing hydrogen concentration.