Sorption-enhanced gasification of municipal solid waste for hydrogen production: a comparative techno-economic analysis using limestone, dolomite and doped limestone

Sorption-enhanced gasification has been shown as a viable low-carbon alternative to conventional gasification, as it enables simultaneous gasification with in-situ CO2 capture to enhance the production of H-2. CaO-based sorbents have been a preferred choice due to their low cost and wide availability. This work assessed the technical and economic viability of sorption-enhanced gasification using natural limestone, doped limestone with seawater and dolomite. The techno-economic performance of the sorption-enhanced gasification using different sorbents was compared with that of conventional gasification. Regarding the thermodynamic performance, dolomite presented the worst performance (46.0% of H-2 production efficiency), whereas doped limestone presented the highest H-2 production efficiency (50.0%). The use of dolomite also resulted in the highest levelised cost of hydrogen (5.4 euro/kg against 5.0 euro/kg when limestone is used as sorbent), which translates into a CO2 avoided cost ranging between 114.9 euro/tCO(2) (natural limestone) and 130.4 euro/tCO(2) (dolomite). Although doped limestone has shown a CO2 avoided cost of 117.7 euro/tCO(2), this can be reduced if the production cost of doped limestone is lower than 42.6 euro/t. The production costs of new sorbents for CO2 capture and H-2 production need to be similar to that of natural limestone to become an attractive alternative to natural limestone.