Experimental and kinetic study of catalytic steam gasification of low rank coal with an environmentally friendly, inexpensive composite K2CO3–eggshell derived CaO catalyst

• Published in: Fuel (Guildford) Vol. 165; pp. 397 - 404
• Main Authors: Fan, ShuMin, Yuan, XiangZhou, Zhao, Liang, Xu, Li-Hua, Kang, Tae-Jin, Kim, Hyung-Taek
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2016
• Subjects: Activation energy; Catalytic coal gasification; Eggshell; K2CO3; Kinetic models; Low rank coal; Catalytic coal gasification; Eggshell; K2CO3; Low rank coal; Activation energy; Kinetic models
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2015.10.084

•The composite catalyst improved the yields of H2-rich syngas.•RPM was the best model to fit the experimental data.•The composite catalyst performed higher catalysis ability at 800 and 900°C.•The composite catalyst reduced the activation energy about 51kJ/mol. The objective of this research was to study effects of composite catalysts (K2CO3 and eggshell derived CaO) on gasification of Indonesian sub-bituminous KPU coal, which was conducted in a fixed bed reactor at atmospheric pressure. The effects of composite catalysts were evaluated from two sections: syngas compositions and reactivity. At 800°C, the H2 yield of 1.34mol/mol-C was obtained and the H2 fraction was 62vol% when using the composite catalyst (15%K+5%ES). Compared with only utilization of pure K2CO3 and no catalyst, the composite catalyst (15%K+5%ES) could increase the yields of H2 by 6% and 123%. In addition, a CO yield of 0.32mol/mol-C was obtained by utilizing composite catalyst (15%K+5%ES), and the CO yield increased by 19% compared with utilization of K2CO3 and increased by 100% compared with no catalyst utilization. Through regression, kinetic parameters were determined from the random pore model (RPM), which provided a basis for design and operation of a realistic system. The RPM could adequately describe the conversion rate. Compared with results of non-catalytic steam gasification, the composite catalyst (15%K+5%ES) was active in increasing the carbon conversion rate constant by more than three times within 700–900°C due to its ability to reduce the activation energy of gasification by about 38%. It can be concluded that the composite catalyst not only enhances the catalytic effect, but also is environmentally friendly and inexpensive.