Zn催化剂对次烟煤及其镜质组富集物催化解聚影响

ZnCl_(2)catalyst on the catalytic depolymerization of sub-bituminouscoal and its vitrinite-rich concentrate

选用一种次烟煤为研究对象,利用格金干馏实验装置、全二维气相色谱-质谱联用仪(GC×GC-MS)、气相色谱仪,通过考察添加不同含量的ZnCl_(2)催化剂对催化解聚产物分布、焦油组成、气体组成及半焦的影响,探讨添加ZnCl_(2)催化剂及催化剂添加量对原煤催化解聚反应的影响规律和可能作用机制。催化解聚产物分布结果表明,添加Zn基催化剂可促进煤热反应程度,降低半焦产率,提高焦油产率。Zn添加量为0.10%时对煤热反应过程的促进程度最高,焦油产率增加也最高,从原煤的12.05%增加至13.83%,其焦油组分分析表明,焦油中多环芳烃类物质的相对含量增加幅度最大。结合气体组分分析,气相中H_(2)体积分数增加明显,而CH_(4)体积分数略有降低,C^(2+)等低碳烃类气体明显减少,CO,CO_(2)体积分数基本不变,表明在Zn基催化剂作用下,较小自由基更倾向于与一些大自由基碎片结合生成大分子焦油,而不是小分子气体。在此基础上,考察了0.10%Zn基催化剂添加对原煤提质分离所得的镜质组富集煤样的催化解聚效果,结果表明,原煤提质可显著提升焦油产率,镜质组富集煤样焦油产率达到16.17%,较原煤增加了4.12%,且Zn基催化剂添加可进一步提升镜质组富集煤样热解聚程度,进一步提升焦油产率至17.87%。

The effects of adding different contents of ZnCl_(2)catalysts into sub-bituminous coal on the catalytic depolymerization products of tar composition,gas phase composition and char were investigated by Gray-King assay,gas chromatography analysis,and comprehensive two-dimensional gas chromatography-mass spectrometry(GC×GC-MS)and its possible catalytic mechanism was discussed.The product distribution results showed that after the addition of the ZnCl_(2)catalyst,the yield of char was reduced and the yield of tar was improved.When the addition amount of Zn was 0.10%,the promotion effect on the pyrolysis catalytic depolymerization was the highest,the tar yield increased to 13.83%compared with 12.05%of the raw coal.According to the results of tar components analysis,the content of polycyclic aromatic hydrocarbons in the tar increased the most.Gas-phase composition analysis showed that the H_(2)content increased significantly,while the CH_(4)content decreased slightly,the C^(2+)and other low-carbon hydrocarbons decreased significantly,and the CO and CO_(2)yields remained basically unchanged.It indicates that with the addition of the Zn-based catalyst,free radicals were more inclined to generate large molecular tar with some large free radical fragments,rather than small molecular gases.Moreover,the catalytic depolymerization effect of the addition of 0.10%Zn-based catalyst on the vitrinite-rich concentrate obtained from the separation of the sub-bituminous coal was investigated.The tar yield obtained from the depolymerization of the vitrinite-rich concentrate reached 16.17%,which was an increase of 4.12%compared to the raw coal.Also the Zn catalyst addition could further increase the thermal depolymerization degree of vitrinite-rich concentrate and further increase the tar yield to 17.87%.