RESEARCH ARTICLE

Effect of pressure on gasification reactivity of three Chinese coals with different ranks

  • Chunyu LI 1,2 ,
  • Jiantao ZHAO , 1 ,
  • Yitian FANG , 1 ,
  • Yang WANG 1
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  • 1. Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
  • 2. Graduate School of Chinese Academy of Sciences, Beijing 100039, China

Received date: 02 Nov 2009

Accepted date: 04 Apr 2010

Published date: 05 Dec 2010

Copyright

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg

Abstract

The gasification reactivities of three kinds of different coal ranks (Huolinhe lignite, Shenmu bituminous coal, and Jincheng anthracite) with CO2 and H2O was carried out on a self-made pressurized fixed-bed reactor at increased pressures (up to 1.0 MPa). The physicochemical characteristics of the chars at various levels of carbon conversion were studied via scanning electron microscopy (SEM), X-ray diffraction (XRD), and BET surface area. Results show that the char gasification reactivity increases with increasing partial pressure. The gasification reaction is controlled by pore diffusion, the rate decreases with increasing total system pressure, and under chemical kinetic control there is no pressure dependence. In general, gasification rates decrease for coals of progressively higher rank. The experimental results could be well described by the shrinking core model for three chars during steam and CO2 gasification. The values of reaction order n with steam were 0.49, 0.46, 0.43, respectively. Meanwhile, the values of reaction order n with CO2 were 0.31, 0.28, 0.26, respectively. With the coal rank increasing, the pressure order m is higher, the activation energies increase slightly with steam, and the activation energy with CO2 increases noticeably. As the carbon conversion increases, the degree of graphitization is enhanced. The surface area of the gasified char increases rapidly with the progress of gasification and peaks at about 40% of char gasification.

Cite this article

Chunyu LI , Jiantao ZHAO , Yitian FANG , Yang WANG . Effect of pressure on gasification reactivity of three Chinese coals with different ranks[J]. Frontiers of Chemical Science and Engineering, 2010 , 4(4) : 385 -393 . DOI: 10.1007/s11705-010-0501-1

Acknowledgments

This work was supported by the Major State Basic Research Development Program of China (973 Program, Grant No. 2006JQJ11131) , the National High-Tech R&D program of China (863 program, No.2008AA050302).
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