Process modelling of amine unit for carbon capture in the context of the cement industry

Abstract

The steady build-up of greenhouse gases in the atmosphere is fast becoming one of the major environmental problems of our time. Among these gases, carbon dioxide (CO2) accounts for over three-fourths of the global gas emissions, with power generation and other energy-intensive sectors being largely responsible for its emissions. Cement production is a very relevant industry, accounting for 2.4 Gt of CO2 emissions, representing about 7% of total global emissions of CO2. Monoethanolamine (MEA) has had wide acceptance as a solvent in carbon capture, whereas it requires a large amount of energy for solvent regeneration; therefore, another solvent known as CESAR-1, which is an aqueous solution of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ), has been studied by FP7 CESAR (Framework Programme) project to provide higher uptake of CO2 and low regeneration energy requirement. This study aims to develop a carbon capture model based on the flue gas data obtained from a previous European consortium project CEMCAP. The system, which has not yet undergone commercial validation, is modelled within the process simulation software Aspen PlusTM. The process model was initially developed using the CESAR-1 solvent. Following this, process modifications, including absorber interstage cooling (AIS), were implemented to reduce energy consumption. Subsequently, a comparative assessment was carried out against the benchmark solvent MEA, focusing on solvent consumption, reboiler duty, and utilities requirements for the entire plant. Because of its high CO2 loading capacity, CESAR-1 solvent requires less solvent for the same capture efficiency than MEA, which results in lower regeneration energy and utility demands. Overall, this study shows that CESAR-1 solvent offers better performance with lower energy consumption and utility requirements. This suggests that it is a viable choice for improving the sustainability and efficiency of carbon capture in the cement sector.