Biomass CO2 gasification with CaO looping for syngas production in a fixed-bed reactor

Abstract

The most important challenge in solid feedstock thermal conversion methods is minimising $CO_{2}$ emissions. In this work, the gasification of pine sawdust in a mixture of $N_{2}$ and $CO_{2}$ was investigated for the reduction of $CO_{2}$ by a calcium oxide loop. The experiments were conducted at 600, 700, and 800 °C in a fixed-bed reactor. The biomass was mixed with the calcium oxide at a ratio of 1:1. The chemical composition of the syngas was analysed using gas chromatography. Moreover, the high heating values of the received gas samples were calculated, and thermogravimetric analysis and Fourier-transform infrared spectroscopy analysis were performed to investigate the absorption of $CO_{2}$ by $CaO$. The results of the gasification process showed that the syngas contained $CO$, $CH_{4}$, $CO_{2}$, $H_{2}$, $N_{2}$, and other low hydrocarbons. The most significant results were obtained for a 2:1 ratio of $N_{2}$ to $CO_{2}$ at 700 °C, and a $CO_{2}$ reduction of 25% was observed. Moreover, the catalytic properties of $CaO$ increased the concentration of $H_{2}$ in the produced syngas by up to 10%. A temperature of 800 °C was too high for the carbonation reaction of $CaO$. This study presents a possible solution for achieving negative carbon emissions.