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

Abstract The objective of this research was to study effects of composite catalysts (K 2 CO 3 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 H 2 yield of 1.34 mol/mol-C was obtained and the H 2 fraction was 62 vol% when using the composite catalyst (15%K + 5%ES). Compared with only utilization of pure K 2 CO 3 and no catalyst, the composite catalyst (15%K + 5%ES) could increase the yields of H 2 by 6% and 123%. In addition, a CO yield of 0.32 mol/mol-C was obtained by utilizing composite catalyst (15%K + 5%ES), and the CO yield increased by 19% compared with utilization of K 2 CO 3 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.