Coal structure change by ionic liquid pretreatment for enhancement of fixed-bed gasification with steam and CO2

An innovative pretreatment of Indonesian low-rank coal (ILRC) by 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) ionic liquid (IL) was conducted. The obtained IL pretreated coal had a loose and porous structure. Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis showed that pretreated ILRC had a stronger absorption ability and an increased average pore size (from 23.6 to 51.8 nm). Steam-coal gasification was conducted to explore the effect of coal pretreatment. The result showed that 1.63-times more hydrogen was generated from pretreated coal compared to original (i.e., untreated) coal, and carbon conversion (X c ) increased from 89.03 to 97.25%. During CO2 coal gasification, IL pretreated coal had a greater CO2 consumption potential and generated more CO. The chemical exergy of syngas of the pretreated coal gasification was higher than that of the untreated coal gasification with CO2 at 900 °C. In addition, pretreated coal emitted less CO2 than untreated coal at 900 °C.