CO_2气氛中低变质煤微波热解研究

Study on microwave pyrolysis of low rank coal under CO_2 atmosphere

煤-循环煤气微波共热解是煤清洁高效转化利用的一种新技术。为深入剖析其作用机理,主要研究了二氧化碳气氛中低变质煤的微波热解过程,系统考察了微波功率、热解时间、气体流量和煤样粒度等因素对热解产品收率、组成及煤气成分的影响。结果表明:CO2加剧了低变质煤的微波裂解程度,使原煤中挥发分析出较多,有机质分解加快,兰炭中矿物质有效富集。在微波功率960 W、热解时间40 min、CO2流量0.56 L/min、低变质煤样粒度5~10 mm的优化工艺条件下热解,兰炭收率最高可达60.8%,液体产品(煤焦油和热解水)收率最高可达21.8%,煤气中有价成分(CO+CH4+H2)体积分数达54.03%。所得兰炭中固定碳含量达84.89%,满足FC-4级兰炭标准;挥发分含量为4.86%,满足V-1级兰炭标准。所得煤焦油中烷烃类化合物含量高达35.5%。

Microwave co-pyrolysis of coal and circulating gas is a new technology to convert and utilize coal cleanly and effectively.In order to further understand the action mechanism of each single component in circulating gas,the effect of microwave power,pyrolysis time,gas flow rate and particle size of coal samples on the yield and composition of microwave pyrolysis products of low rank coal were studied by the microwave co-pyrolysis experiment under carbon dioxide atmosphere.The results indicate that carbon dioxide promotes the microwave pyrolysis of low rank coal to accelerate the decomposition of organic matters and generate much more volatile of raw coal,thus make the effective enrichment of minerals in blue-coke.The yields of the blue-coke and liquid products( coal tar and pyrolysis water) from microwave pyrolysis products are up to 60.8% and 21.8% respectively,and the valuable components content of gas( CO +CH4+ H2) is up to 54.03% when the optimal process conditions with the microwave power of 960 W,pyrolysis time of40 min,carbon dioxide flow rate of 0.56 L / min and coal samples particle size of 5-10 mm are selected.The content offixed carbon is up to 84.89% to meet Blue-coke Standard FC-4 Grade,volatile content is up to 4.86% to meet Bluecoke Standard V-1 Grade.The content of alkane compounds is up to 35.5%.