Evolution Mechanism of Carbon Covalent Bond during Coal Activation Using Mixed Atmosphere of H2O and CO2

  • WANG Mingyue ,
  • ZHANG Siyuan ,
  • HAN Shaobo ,
  • ZHANG Chi ,
  • REN Qiangqiang
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  • 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

Online published: 2024-09-09

Supported by

This work was supported by the CAS Project for Young Scientists in Basic Research (YSBR-028).

Copyright

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2024

Abstract

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 H2O to CO2 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. CO2 mainly participates in the cross-linking reaction by intensifying branching, while H2O 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 H2O 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.

Cite this article

WANG Mingyue , ZHANG Siyuan , HAN Shaobo , ZHANG Chi , REN Qiangqiang . Evolution Mechanism of Carbon Covalent Bond during Coal Activation Using Mixed Atmosphere of H2O and CO2[J]. Journal of Thermal Science, 2024 , 33(5) : 1961 -1973 . DOI: 10.1007/s11630-024-2006-0

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