An experimental characterization of Calcium Looping integrated with concentrated solar power

Carbon Capture and Sequestration (CCS) and renewable energy sources are both essential to mitigate the CO2emissions in the near future. Calcium Looping (CaL) is an important post-combustion carbon capture technologythat has reached the maturity of the pilot plant stage. On the other side Concentrated Solar Power (CSP) is a fastgrowingrenewable technology in which solar energy, concentrated up to several MW m−2, can be used toproduce electricity or to drive an endothermic chemical reaction. The integration between a CSP system and aCaL cycle, in order to use a renewable source to supply the energy required by the calciner, would stronglyimprove the performance of the CaL process by overcoming some of its main drawbacks. However, the role thathighly concentrated radiation can have on the sorbent properties in the CaL cycle is still matter of investigation.In this study, the CaL-CSP integrated process is experimentally investigated through the use of a directly irradiatedFluidized Bed (FB) reactor. Simulated concentrated solar radiation featured a peak flux on the FB surfaceof approximately 3 MW m−2 and a total power of about 3 kWth. Several calcination and carbonation tests havebeen performed on samples of a commercial Italian limestone, in order to establish the evolution of the sorbentcapacity of CO2 capture at increasing number of cycles. The properties of the limestone samples were furtherinvestigated by means of microstructural characterization. The comparison between results obtained with andwithout the use of the solar concentrated flux to thermally sustain calcination provides useful information on thepotential of solar driven CaL and on the measure to overcome some of its potential limitations.