Elucidation of syngas composition from catalytic steam gasification of lignin, cellulose, actual and simulated biomasses

Abstract

This work presents research into the gasification of cellulose, lignin, simulated and two actual biomasses which are rich in cellulose and lignin contents, in order to evaluate and compare their gas products and also understand their gasification processes in presence of CaO by varying the CaO to biomass feed ratio from 0 to 1.5 at 700 °C. Biomass components at the optimum CaO loading were gasified at different temperatures ranging from 600 to 800 °C, and then actual and simulated biomasses were gasified at optimum observed temperature. It was observed that increasing the CaO/cellulose ratio from 0 to 1.5 enhanced the H2 improvement. In contrast, the hydrogen yield in lignin gasification slightly reduced when CaO/lignin mass ratio was more than 1; this could be the due to (i) lower content of sodium (Na) in the gasified sample at CaO/lignin ratio 1.5 and (ii) interaction of Ca(OH)2 with H2 molecules with increasing the Ca atoms. Maximum H2 concentration was achieved with their corresponding CaO loading ratio at 650 °C in both the components. The selected biomass components not only have an effect on product gases but also have a significant influence on the catalyst activity. The gas evolution trend from actual and simulated biomasses results was similar to those selected biomass components. Thus, the higher cellulose content of the biomass, the higher would be the CO yield. Correspondingly, the higher the lignin percentage of the biomass, the higher could be the CH4, CO2, and H2 yields.