A Hybrid Carbon Capture System of Indirect Calcination and Amine Absorption for a Cement Plant

Abstract

AbstractHere we present the process integration of the indirect calcination process existing in the literature [1] into a cement plant. The indirect calcination process is composed of a circulating fluidized bed combustor and a fluidized bed calciner where hot solid particles are circulated between those reactors for heat transfer. It allows separation of CO2 from limestone calcination in a concentrated form. The process integration proposed in this study minimizes the total thermal energy requirement by using excess energy from high temperature flue gases for cement raw meal preheating as in the conventional cement manufacturing process. It also suggests a new hybrid carbon capture system where an additional CO2 capture unit is combined with the indirect calcination process, since the standalone indirect calcination application can only provide a moderate level of CO2 avoidance. The amine process is added to increase CO2 avoidance rate further. Full process flowsheets have been developed and analyzed using the commercial software UniSim Design R400 from Honeywell. The hybrid system can achieve more than 90% carbon capture rate thanks to the supplementary amine process while the indirect calcination can capture only 56% without the amine process. With the support of a simple and transparent economic analysis, the capture cost involved in the hybrid system was estimated to be higher than that of the indirect calcination only but significantly lower than that of the standalone amine process on a basis of unit CO2 avoided