Process Simulation of a Dual Fluidized Bed Ca‑Looping Biomass Gasifer with CuO/CaO for Enhanced Hydrogen Production

In this study, H2 production through Calcium-Looping (Ca-Looping) gasification process using biomass feedstocks, including wood waste (WW), cow manure (CM), and biocrude (BC), was investigated. This novel system employed a dual fluidized bed system, comprising a gasifier reactor with a mixture of CuO and CaO fluidized by steam, and a regenerative air reactor. Hydrogen production was investigated as a function of variations in key operating parameters, including gasification temperature (Tg), equivalence ratio (E/R), steam mass flow rate (Msteam), and CaO circulation rate (CCaO). Enhancement in hydrogen production was not observed at temperatures above 700 °C for all feedstocks, which was confirmed to be due to the deactivation of the carbonation reaction. An increasing CO2 volume fraction and decreasing H2 volume fraction in the synthesis gas were observed as the E/R ratio increased. Additionally, H2 production increased continuously with higher steam flow rate. CO2 capturing capacity, through carbonation of CaO increased with CaO circulation rates, reaching a plateau as the circulation rate reach above 100 kg/hr. These findings highlight the potential of the biomass Ca-Looping gasification process to produce high-purity H2 while significantly reducing CO2 emissions, positioning it as a promising pathway for sustainable energy production.