Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO₂ capture

Abstract

Abstract Over the last few decades, research on the abatement of carbon dioxide (CO 2 ) gas has gained momentum, due to its increasing atmospheric levels. This study investigated high‐temperature steam‐only gasification of woody biomass for the production of high‐purity hydrogen integrated with CO 2 capture in a moving‐bed gasifier. Extensive process modelling and simulation were performed using the superior solid handling features of the Aspen Plus process simulator software. After validating the model with experimental data from a demonstration plant available in the open literature, a reversible carbonation‐calcination reaction of calcium oxide (CaO) with CO 2 was added to the system. Sensitivity analyses were conducted to verify the predictive accuracy of the model. The effects of steam‐to‐carbon (S/C) ratio on the resulting gas composition were thoroughly studied to delineate the complex process of gasification. Beyond the mitigation of CO 2 emissions, the introduction of a CaO‐based sorbent in the process simulation significantly enhanced hydrogen production by simultaneously promoting the forward water‐gas shift reaction and reducing tars through increased tar‐cracking reactions. The results show that hydrogen of a higher purity was produced with the inclusion of dry‐sorption CO 2 capture in the gasification process. Moreover, the addition of the sorbent increased the higher heating values (HHV) by 3 times and improved the cold gas efficiency by 34 %.