梁丽彤, 张乾, 黄伟, 等. 低阶煤催化解聚半焦的孔结构特点与CO2气化反应性[J]. 煤炭学报, 2020, 45(10): 3573-3579. DOI: 10.13225/j.cnki.jccs.2019.1194
引用本文: 梁丽彤, 张乾, 黄伟, 等. 低阶煤催化解聚半焦的孔结构特点与CO2气化反应性[J]. 煤炭学报, 2020, 45(10): 3573-3579. DOI: 10.13225/j.cnki.jccs.2019.1194
LIANG Litong, ZHANG Qian, HUANG Wei, et al. Pore structure characteristics and gasification reactivity under CO2 of char from catalytic depolymerization of low-rank coal[J]. Journal of China Coal Society, 2020, 45(10): 3573-3579. DOI: 10.13225/j.cnki.jccs.2019.1194
Citation: LIANG Litong, ZHANG Qian, HUANG Wei, et al. Pore structure characteristics and gasification reactivity under CO2 of char from catalytic depolymerization of low-rank coal[J]. Journal of China Coal Society, 2020, 45(10): 3573-3579. DOI: 10.13225/j.cnki.jccs.2019.1194

低阶煤催化解聚半焦的孔结构特点与CO2气化反应性

Pore structure characteristics and gasification reactivity under CO2 of char from catalytic depolymerization of low-rank coal

  • 摘要: 低阶煤催化解聚技术旨在通过催化剂的作用,促进煤大分子结构在低温下解聚形成更多的焦油成分。前期研究发现催化剂在使煤热解焦油收率增加、焦油品质轻质化的同时,也使半焦的聚合度降低。本研究旨在探讨催化剂作用下聚合度降低的半焦其相应的孔结构及气化反应性发生的变化。应用N2吸附与TG分析仪考察了铁基催化剂与钼基催化剂对中温催化解聚半焦的孔结构特点与CO2气化反应性的影响。认为催化剂促进了煤中含氧基团的断裂,使半焦中氧含量降低,表面性质发生了变化,从而使内蒙煤在催化剂作用下解聚半焦的吸附等温线由原煤热解半焦的Ⅰ型变为Ⅴ型,新疆煤焦的吸附等温线由原煤热解半焦的Ⅱ型变为加钼后的Ⅳ型和加铁后的Ⅴ型。在催化解聚过程中,催化剂通过对热解半焦碎片的加氢,抑制了半焦的缩聚,使半焦的介孔数量增多,比表面积和孔容增大,其中钼催化剂的增孔作用更为显著,内蒙煤加钼半焦孔容为原煤半焦的2.14倍,新疆煤加钼半焦孔容为原煤半焦的16.5倍。催化剂本身对半焦的气化反应没有明显影响,而是通过干预煤的热解过程使半焦形成更多介孔,增大半焦的比表面积及孔容而使半焦的气化反应性能得到明显提高。半焦等温吸附线的变化及孔容的增加,也为拓展催化解聚半焦的利用途径提供了可能,作为多孔材料,可进一步考察煤解聚催化剂对半焦吸附性能的影响,探讨其在污水处理、气体净化等方面的应用。

     

    Abstract: The catalytic depolymerization technology of low rank coal aims to obtain more tar through the promotion of depolymerization coal macromolecular structure at low temperatures. The addition of catalyst in the catalytic depolymer- ization process can not only increase the yield and quality of tar,but also reduce the polymerization degree of char. This study is mainly to investigate the gasification performance of the chars with the variation of pore structure. The effect of Fe based catalyst and Mo based catalyst on the pore structure and CO2 gasification reactivity of the respective chars were investigated by TG analyzer and N2 adsorption. The results showed that the catalyst promoted the bond breaking of the oxygen-containing groups in coal,reduced the oxygen content in char,and changed the surface proper- ties,and finally caused the change of adsorption isotherm of Inner Mongolia char with catalyst from type I of raw coal pyrolysis semi-coke to type V,and the change of adsorption isotherm of Xinjiang char of raw coal pyrolysis from type II to type IV after Mo based catalyst addition and to type V after Fe based catalyst addition. The catalyst inhibited the polycondensation of char in the process of catalytic depolymerization,which increased the number of mesopores,sur- face area and pore volume of char,especially for the Mo catalyst addition. The pore volume of Inner Mongolia char with Mo catalyst was 2. 14 times of that of raw coal char,and the pore volume of Xinjiang coal with Mo catalyst was 16. 5 times of that of raw coal char. The catalyst addition had no obvious effect on the gasification reactivity of the char, while with intervening the pyrolysis process of coal,the char formed more mesopores,and the specific surface area and pore volume of char increased,thus the gasification performance of char improved significantly. The change of isotherm ad-sorption line and the increase of pore volume of char also provided the possibility to expand the utilization of the obtained char. As a porous material,the influence of coal depolymerization catalyst on the adsorption perfor-mance of the char could be further investigated,which has an application possibility in sewage treatment and gas purification.

     

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