Economic Evaluation of Selexol – Based CO 2 Capture Process for a Cement Plant Using Post – Combustion Technology

Abstract

This research work focuses on the economic evaluation of post-combustion technology to capture CO2 from a based Cement Plant using a physical absorption solvent called Dimethyl Ether Polyethylene Glycol-DEPG (Selexol). The low cost Selexol absorption unit captured 97% of the CO2 with 98% purity by mole of the CO2 through absorption into a 0.37 mole CO2/mole Selexol lean loading of the physical solvent. A detailed cost estimation of the CO2 postcombustion unit of the plant was carried out in order to evaluate the economic performance of the process and cost of CO2 captured, the additional utility costs associated with this technology. The CO2 capture cost per tonne of CO2 captured was found to be $58 (₦9,333). The Total Operating Cost was estimated at $27,542,469 (₦4.5Billion) and the Total Capital cost was estimated at $19,222,886 (₦3.08 Billion). The raw material cost was the highest cost in the CO2 capture process with a value of $19,500,000 (₦3.1 Billion) representing 71% of the total operating cost. Sensitivity analysis cases of the impact of absorber temperature, pressure and absorber inlet gas temperature on liquid and vapour flow, percentage CO2 recovery, energy consumption, annual operating and capital costs and cost of CO2 captured were studied. The overall result of the analysis shows that Selexol has proven to be thermally, chemically stable and commercially justifiable under the operating conditions used.