Evolution Mechanism of Carbon Covalent Bond during Coal Activation Using Mixed Atmosphere of H_(2)O and CO_(2)  

作　　者：WANG Mingyue ZHANG Siyuan HAN Shaobo ZHANG Chi REN Qiangqiang 

机构地区：[1]Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]State Key Laboratory of Coal Conversion,Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Journal of Thermal Science》2024年第5期1961-1973,共13页热科学学报（英文版）

基　　金：supported by the CAS Project for Young Scientists in Basic Research(YSBR-028)。

摘　　要：Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants.In this research,activation reactions of Shenmu coal powder were carried out in a vertical tube furnace.The study investigated the evolution mechanism of carbon covalent bonds during the activation process by altering the ratio of H_(2)O to CO_(2)in the activation atmosphere.The theoretical validation was conducted through density functional calculations.The two gas molecules follow different pathways to increase the reactivity of char.CO_(2)mainly participates in the cross-linking reaction by intensifying branching,while H_(2)O and char have lower adsorption energy barriers and are more likely to generate oxygen-containing functional groups.Gas molecules partially compete for active sites in a mixed gas atmosphere,but there is a synergism between the two effects.The synergism can be attributed to two possibilities.The inclusion of H_(2)O mitigates the generation of five-membered rings to a limited extent,while concurrently enhances the development of oxygen-containing functional groups.Introducing oxygen-containing functional groups can effectively diminish the adsorption energy barrier associated with the interaction between gas molecules and char,consequently leading to a reduction in the energy demand for subsequent bond cleavage.

关 键 词：activation reaction carbon structure CHAR CO_(2)/H_(2)O atmosphere density functional theory 

分 类 号：TK16[动力工程及工程热物理—热能工程]