低变质煤-循环煤气微波共热解研究

Study on Microwave Co-Pyrolysis of Low Rank Coal and Circulating Coal Gas

低变质煤干馏热解生产兰炭、煤焦油、煤气被认为是其清洁高效转化利用的最佳途径。现有主流生产工艺普遍对原煤具有一定的粒度要求,煤焦油产量较低、质量不高,煤气中H_2,CH_4,CO等有效组分含量较低。为进一步提高低变质煤热解时煤焦油收率和质量,提出将微波热解低变质煤产生的煤气循环通入微波热解反应器中,进行低变质煤-循环煤气微波共热解。结合FTIR及GC-MS等对热解产品的分析表征,系统考察了微波功率、热解时间、煤样粒度对热解产品收率及组成的影响。研究结果表明:低变质煤在循环煤气流量为0.4L·min^(-1)、微波功率为800W、热解时间为40min、煤样粒度为5~10mm的工艺条件下热解,所得固体产品兰炭收率达62.2%,液体产品(煤焦油和热解水)收率达26.8%。不同微波功率及热解时间下所得兰炭红外谱线基本重合;不同粒度煤样热解所得兰炭中—OH,C=O,C=C和C—O官能团含量差别较大。提高微波功率、延长热解时间、减小煤样粒度均有利于煤焦油的轻质化。

The pyrolysis of low rank coal to produce bluecoke,coal tar and gas is considered to be the optimal method to realize its clean and efficient utilization.However,the current mainstream pyrolysis production technology generally has a certain particle size requirements for raw coal,resulting in lower yield and poorer quality of coal tar,lower content of effective components in coal gas such as H_2,CH_4,CO,etc.To further improve the yield of coal tar obtained from the pyrolysis of low rank coal and explore systematically the effect of microwave power,pyrolysis time and particle size of coal samples on the yield and composition of microwave pyrolysis products of low rank coal through the analysis and characterization of products with FTIR and GC-MS,introducing microwave pyrolysis of low rank coal into the microwave pyrolysis reactor circularly was suggested to carry out the co-pyrolysis experiment of the low rank coal and coal gas generated by the pyrolysis of low rank coal.The results indicated that the yield of the bluecoke and liquid products were up to 62.2% and 26.8%respectively when the optimal pyrolysis process conditions with the microwave power of 800 W,pyrolysis time of 40 min,coal samples particle size of 5~10mm and circulating coal gas flow rate of 0.4L·min^（-1） were selected.The infrared spectrogram of the bluecoke under different microwave power and pyrolysis time overlapped roughly.The content of functional groups with —OH,C—O,C— C and C—O from the bluecoke through the pyrolysis of particle size coal samples had a larger difference.To improve microwave power,prolonging pyrolysis time and reducing particle size of coal samples were conducive to converting heavy component to light one into coal tar.