Study of CaO - Based synthetic sorbents for the CO2 capture in the production of high hydrogen content syngas from biomass gasification

Steam biomass gasification by fluidized bed reactor systems is a very promising technology for extracting the renewable energy content of the biomass: coupled with the in situ CO2 sorption, by the way of powder sorbents into the bed, it's possible to achieve a hydrogen content suitable for Fuel Cell feeding (80% hydrogen content with sorption- 40% without sorption). Common and cheap sorbents are naturals CaO based powders (dolomite and limestone), but they present a limited cycling resistance (around 50% decrease of the efficiency after 10 cycles) that limits their use in real conditions. The aim of this work is the realization of synthetic sorbents by means of hydrolysis technique consisting of CaO on Mayenite binder (Ca12Al14O33) to increase the cycling resistance and the CO2 sorption efficiency. The influence of C O precursor; CaO / Ca12Al14O33 weight ratio and CaO grain size distribution has been considered. The 75/25 powder obtained by Ca(CH3COO)2 precursor with fine starting granulometric distribution (d32 =2.6 μm), showed an efficiency around 80% of the theoretical one, almost stable along all the 25 cycles carried out, very important feature for the syngas synthesis process.