Improved process modifications of aqueous ammonia-based CO₂ capture system

¹ Department of Chemical Engineering, Curtin University Malaysia, CDT 250, Miri 98009, Sarawak, Malaysia
² Curtin Malaysia Research Institute (CMRI), Curtin University Malaysia, CDT 250, Miri 98009, Sarawak, Malaysia

Corresponding author: agus.saptoro@curtin.edu.my

Abstract

Extensive research works on CO2 capture process using MEA have been carried out and showed promising results. Nevertheless, it has been acknowledged that the use of MEA is associated with high cost, solvent degradation issues and corrosion. The issues above have motivated researchers to explore and test other potential solvents such as aqueous ammonia (NH₃). As result, NH₃ based CO₂ capture systems have recently attracted much attention as an alternative to MEA based counterparts. Despite their encouraging applications, high volatility of NH₃ raise concerns on the energy requirement related to the solvent recovery. Consequently, energy efficient NH₃ based CO₂ capture systems by modifying the process is desirable. This study, therefore, aims to propose and evaluate three different stand-alone process configurations of absorption-desorption processes in a NH₃-based system and compare them with the traditional absorption-desorption system in respect to total energy consumption. These modifications include Rich Solvent Split (RSS), Lean Vapor Compression (LVC), and Rich Vapor Compression (RVC). Results indicate that among these three proposed process modifications, LVC led to the highest reboiler energy savings of 38.3% and total energy savings of 34.5% compared to NH₃ based conventional configuration. These findings can serve as essential recommendations for further studies on and large-scale implementations of aqueous NH₃ as a better solvent.