Advanced post combustion CO₂ capture process – A systematic approach to minimize thermal energy requirement

The high thermal energy consumption required for solvent regeneration hinders the commercial-scale implementation of the solvent based carbon dioxide capture and storage process. Process modification is an effective method to reduce the energy requirement of the process. In this study we have developed a new systematic approach to modify and reduce the energy consumption of the process by splitting the regeneration energy into different parts to calculate the magnitude of avoidable components. The process is then modified, aiming to reduce the avoidable components of the regeneration energy. The process modification approach is used to design an advanced process with lower regeneration energy. Furthermore, a more realistic approach for retrofitting projects, off-design performance analysis, is used to study the integration of conventional and advanced processes with existing power plant. The power plant is modelled on Ebsilon Professional®, while the carbon dioxide capture process is modelled on Aspen Plus®. The advanced process reduces the reaction heat by 5%, sensible heat by 6.6%, and unproductive heat by 85.4%. The advanced process decreases the total thermal energy requirement by 25.5% compared to that of the conventional process. Off-design performance analysis reveals that integration of the advanced process improves the net power output by 17 MW and reduces the efficiency penalty from 9.2% to 8.1% as compared to conventional capture process. The advanced process reduces the cost of CO₂ avoided by 2.8 USD/tonCO₂ at the expense of a 0.45 USD/tonCO₂ increase in capital cost.