Calcium Looping Process: Experimental investigation of limestone performance regenerated under high CO2 partial pressure and validation of a carbonator model

A key aspect of the Calcium Looping process is the implementation of the oxy-fuel combustion for the endothermic sorbent regeneration, which imposes high partial pressure of CO2 (75vol.-% dry). These conditions enhance lime sintering and thus, the decrease of the sorbent's maximum CO2 carbonation conversion (Xmax), which is an important parameter that influences the CO2 capture. This paper presents results from tests performed in presence of high CO2 volumetric concentration in a 10 kWth Dual Fluidized Bed system. High regeneration extents and CO2 capture efficiencies of more than 80% is attained with sorbent residual activity of 8,5%. A carbonator model is validated and active space time is proposed to be the main parameter to be used for up scaling design purposes.