Activation and mechanism of chars from partial gasification of lignite at different steam concentrations

SHEN Tian; WANG Yong-gang; CHENG Xiang-long; LIN Xiong-chao

Volume 45 Issue 5

May 2017

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Article Navigation > Journal of Fuel Chemistry and Technology > 2017 > 45(5): 513-522

SHEN Tian, WANG Yong-gang, CHENG Xiang-long, LIN Xiong-chao. Activation and mechanism of chars from partial gasification of lignite at different steam concentrations[J]. Journal of Fuel Chemistry and Technology, 2017, 45(5): 513-522.

Citation:

SHEN Tian, WANG Yong-gang, CHENG Xiang-long, LIN Xiong-chao. Activation and mechanism of chars from partial gasification of lignite at different steam concentrations[J]. Journal of Fuel Chemistry and Technology, 2017, 45(5): 513-522.

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Activation and mechanism of chars from partial gasification of lignite at different steam concentrations

School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083

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The project was supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China 2012BAA04B02

Received Date: 2016-12-26
Rev Recd Date: 2017-03-03

Available Online: 2021-01-23

Publish Date: 2017-05-10

Abstract

Abstract

The char samples were prepared from the partial gasification of Shengli lignite in a fluidised-bed/fixed-bed reactor, and characterised by BET, Raman, FT-IR, microwave digestion ICP-AES, and TGA. The results indicate that at 800 ℃ and steam atmosphere the decomposition of ether group is made by the inherent char activation, leading to the decrease in the content of short chain or amorphous carbon between aromatic rings to prevent the graphitizing and the enhancement in the degree of defective aromatic structure. With the increasing of steam concentration (10%-25%) the char reactivity is reduced, which is attributed to the weakening of the regeneration of active sites by forming more ether group via the reaction "Ar, R-CO-Ar, R+2H₂O→Ar, R-O-Ar, R+2H₂+CO₂". However, with the continual increasing of steam concentration (25%-40%) the char reactivity is slightly promoted because the content of defective aromatic structure (3-5 rings) is increased due to the enhancement of the reaction (Ar, R-CH=CH₂+H₂O→Ar, R-CO-CH₃+H₂) and the reaction (Ar, R-+H-→Ar, R-H).
- lignite,
- fluidized-bed,
- active site,
- char structure

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References(23)

References

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