焦煤地下气化模型试验研究

Study on Model Test of Underground Gasification of Coking Coal

为考察煤炭地下气化技术对焦煤的适用性,通过热解试验和地下气化模型试验,测试了焦煤的热解和气化特性。结果表明,焦煤地下气化时气化剂中氧气的最佳体积分数为60%,此时气化效率最高达80%左右,煤气热值在8.36 MJ/Nm3(2 000 kcal/Nm3)左右。但由于焦煤具有较高的黏结性和膨胀性,使得其在地下气化过程中膨胀,析出的胶质体、熔融的煤灰会附着在气化通道的煤壁上阻碍气化剂与煤体的接触,对气化效果带来一定影响。粗煤气和煤气冷凝水中的H2S、HCN、氨氮、苯类、化学需氧量(COD)、挥发酚等污染物含量均超过国家排放标准允许值的几十甚至数百倍,须经过处理后排放。

In order to examine the applicability of underground coal gasification technology for coking coal, the pyrolysis test and model test of underground gasification were carried out.The results shows in the oxygen-enriched air gasification of coking coal, the optimal oxygen concentration was 60%, the gasification efficiency on this condition was about 80%, the heat value of the coal gas was about 8.36 MJ/Nm3 （2 000 kcal/Nm3） .The adhesion and expansion make the liquid plastic mass and melting ash attach on the coal well in the underground coal gasification process, which inhibit the reaction between gasifying agent and coal body, it was difficult to obtain good gasification effect. The contents of H2S,HCN,ammonia nitrogen,benzenes, COD,volatile phenols in the crude gas and gas condensate are exceed the national emission standards dozens or even hundreds of times, must be treated before discharge.