Economic Evaluation of Selexol – Based CO2 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 post-combustion 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.