Screening CaO-Based sorbents for Co2 capture in biomass gasifiers

Coupling biomass gasification with in situ CO2 Capture significantly enhances the yield of hydrogen. For this process, CaO is the most likely CO2 sorbent. However, the development of a sorbent that is resistant to physical deterioration and maintains reactivity through multiple cycles is a limiting step in the scale-up and commercial operation of a continuous process. To this end, we describe an experimental protocol for screening CO2 sorbents and then use this to assess the performance of six targeted CaO-based sorbents: CaO derived from commercially available CaCO3 (d(p) = 25.8 mu m), commercially available Ca(OH)(2) (d(p) = 9.2 mu m), precipitated CaCO3 (d(p) = 3.2 mu m), CaCO3 nanoparticles (d(p) = 509.4 nm), and presintered CaO doped with Li2CO3 and with K2CO3. The protocol allows the measurement of reactivity through multiple CO2 capture-and-release cycles; this is a significant step in determining the overall consumption of sorbent and, hence, the cost of one of the key parts of the process.