CO2 Capture Performance Using Biomass-Templated Cement Supported Limestone Pellets

Synthetic biomass-templated cement-supported CaO-based sorbents were produced by the granulation process for high-temperature postcombustion CO2 capture. Commercial flour was used as the biomass and served as a templating agent. The investigation of porosity showed that the pellets with biomass or cement resulted in an enhancement of porosity. Four types of sorbents containing varying proportions of biomass and cement were subjected to 20 cycles in a thermogravimetric analyzer under different calcination conditions. After the first series of tests calcined below 850 degrees C in 100% N-2 all composite sorbents clearly exhibited higher CO2 capture activity than untreated limestone with the exception of sorbents doped by seawater. The biomass-templated cement-supported pellets exhibited the highest CO2 capture level of 46.5% relative to 20.8% for raw limestone after 20 cycles. However, the enhancement in performance was substantially reduced under 950 degrees C calcination condition. Considering the fact that both sorbents supported by cement exhibited relatively high conversion with a maximum value of 19.5%, cement-promoted sorbents appear to be better at resisting harsh calcination conditions. Although flour as biomass-templated material generated a significant enhancement in CO2 capture capacity, further exploration must be carried out to find ways of maintaining outstanding performance for CaO-based sorbents under severe reaction conditions.