Production of hydrogen-rich syngas from absorption-enhanced steam gasification of biomass with conch shell-based absorbents

In this study, steam gasification of pine sawdust is conducted in a fixed-bed reactor in the temperature range 650-700 degrees C with calcined conch shell (CS) serving as a starting absorbent. The CS is further subjected to hydration (HCS) and calcination (CHCS) to prepare a modified absorbent. It is found that the hydration-calcination treatment of CS causes smaller CaO crystal grains with a larger BET surface area and more porous surface. As a consequence, CHCS exhibits higher catalytic activity for tar reforming, faster reaction rate for CO2 absorption and better performance for H-2 selectivity than CS. Elevating the temperature contributes to tar reduction but results in lower H-2 content and higher CO2 content, while an increase in Ca/C leads to higher H-2 content. And the H-2 content can reach approximately 76% with the use of CHCS when temperature and Ca/C ratio are 650 degrees C and 2, respectively. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.