Improving CO2 sorption performance of CaO/Ca3Al2O6 sorbents by thermally pretreated in CO2 atmosphere

摘要

CaO-based CO2 sorbents play a significant role in sorption enhanced methane steam reforming process for hydrogen production and CO2 emission reduction. In this work, pretreatment of CaO/CasAl2O6 sorbents in CO2 atmosphere at different temperatures was investigated for its influence on CO2 sorption capacity and cyclic stability. The sorbents were synthesized to contain a CaO to Al2O3 mass ratios of 9:1, and then subjected to cycling tests with repeated carbonation and calcination process. Results showed that the sorbents pretreated by CO2 at 650 °C obtained a minimum CaO grain size of 40.7 nm and a maximum surface area of 13.1 m~2·g~(-1). This resulted in an increase in CO2 sorption capacity, up to 7.60 mmol CO2·g~(-1) sorbent. After 50 cycles, the CO2 sorption capacity decreased, but still remained 10% above those for the original (no pretreatment) sample. The mechanism about the improved CO2 sorption performance of the pretreated sorbents was also postulated.