Integration of pyrolysis and entrained bed gasification for the production of chemicals from Victorian brown coal process simulation and exergy analysis

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Abstract

This paper introduces a novel process for the integration of pyrolysis and entrained-flow gasification for the as-mined Victorian brown coal containing 65 wt.% moisture. An initial mild pyrolysis of coal is proposed to reduce moisture content, and produce multiple products including char, tar and hydrogen-rich coal gas. Subsequently, the resulting water-free char is subjected to an entrained-flow gasifier, upon the blending of silica additive or high-ash bituminous coal. The resultant syngas passes through a cleaning unit and water gas shift reactor before mixing with the pyrolysis-derived gas to reach a target H2/CO molar ratio of 2.0 that is essential for the synthesis of a number of chemicals. In this paper, process simulation and exergy analysis were conducted to prove the advantages of the proposed process against the conventional drying–gasification combination. The results show that, the proposed pyrolysis–gasification integration process for Victorian brown coal possesses an exergy efficiency 4.5% higher than the drying–gasification process, and 1.5% higher than the drying case for another lignite containing 25 wt.% moisture. A prior removal of 20% of the inherent moisture can further improve the exergy efficiency by 4% for Victorian brown coal. The addition of 20% of black coal is the optimum ratio to improve the ash slagging propensity, as well as improve exergy efficiency compared to the conventional drying–gasification process.
Original languageEnglish
Pages (from-to)21-31
Number of pages11
JournalFuel Processing Technology
Volume155
DOIs
Publication statusPublished - Jan 2017

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