Title: Simulation and exergy analysis of processes for CO₂ capture and utilisation for methanol production

Authors: Oludare J. Odejobi; Chiazor F. Jisieike; Ambrose N. Anozie

Addresses: Applied Thermodynamics and Process Design Research Laboratory, Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife 220005, Nigeria ' Applied Thermodynamics and Process Design Research Laboratory, Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife 220005, Nigeria ' Applied Thermodynamics and Process Design Research Laboratory, Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife 220005, Nigeria

Abstract: Carbon dioxide (CO₂) capture and methanol production processes were simulated using Aspen RefSYS. Exergy analysis was done with EXCEL spreadsheet. Parametric study was done on the CO₂ process to investigate the effects of absorber and reboiler pressure, absorber stages and amine circulation rate on CO₂ absorption, CO₂ recovery and process exergy efficiency. The result shows that stripper recovered almost 90% by mass of CO₂ in the flue gas. The highest irreversibility in the CO₂ capture plant occurred in the rich/lean heat exchanger (820516.24 MW); this is followed by the lean cooler (481343.23 MW) and the stripper (404273.57 MW). CO₂ emissions reduction was 171,838.1 tonnes CO₂/yr. For the methanol plant, the highest irreversibility occurred in the distillation column (25088.4 MW). The study concluded that onsite utilisation of CO₂ from thermal plant would minimise CO₂ leakage during transportation or storage.

Keywords: CO2; carbon dioxide; carbon capture; methanol production; parametric study; exergy analysis; irreversibility; emissions reduction; simulation.

DOI: 10.1504/IJEX.2015.071560

International Journal of Exergy, 2015 Vol.17 No.4, pp.456 - 474

Received: 30 Apr 2014
Accepted: 25 Jul 2014
Published online: 01 Sep 2015 *

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