微负压系统中不同粒径煤粉热解半焦特性研究

CHARACTERISTICS STUDY ON SEMICOKE FROM COAL FAST PYROLYSIS WITH DIFFERENT PARTICLE SIZE UNDER MICRO-NEGATIVE PRESSURE

为了研究煤粉粒径对煤快速热解半焦特性的影响,对微负压系统中煤快速热解产生半焦的收率、灰分、挥发分含量和结构等特性进行了分析.结果表明,随着粒径增加,煤粉热解的活化能逐渐增加,低温区大粒径煤粉热解挥发分逸出量高于小粒径煤粉逸出量.热解半焦收率随着煤粉粒径减小逐渐增加,挥发分中焦油收率却随着煤粉粒径的减小而增加.小粒径煤热解生成的半焦结晶程度较低,边缘碳原子和其他缺陷较多,半焦炭层结构较不致密.极小颗粒中矿物质含量较高导致煤粉粒径越小,所得半焦的灰分含量越高,大粒径煤粉由于在低温区间失重速率快,挥发分逸出量大而导致半焦中残余的挥发分含量较低.

In order to investigate the effects of particle size to characteristics of semi-coke from the coal pyrolysis process,the characteristics of semi-coke including yield,ash content,volatile content,and structure were studied.The results shows that the activation energy increased with coal particle size,and the volatile emission from large particle coal pyrolysis was higher than that from little particle coal pyrolysis in low temperature.The semi-coke yield always decreased with the increase of particle size,while the coal tar yield decreased with the increase of particle size.The structure of semi-coke from little particle coal pyrolysis was not fine and close due to low degree of crystallinity.The ash content of semicoke from little particle coal pyrolysis appeared increasing with the decrease of particle size due to more mineral substance in little particles,while the volatile content of semi-coke from large particle coal pyrolysis was lower caused by more volatile emission during pyrolysis process.