Ultrasound intensify CO2 desorption from pressurized loaded monoethanolamine solutions. II. Optimization and cost estimation

Optimization and cost estimation were performed for the use of ultrasound for intensifying CO2 reboiler stripping from lean monoethanolamine (MEA) aqueous solutions at 1.0 barg. This work was based on typical industrial reboiler operation conditions. Experiments were run by intermittently applying ultrasound for CO2 stripping. A multi-variable data analysis was employed to explain the results and find the optimum for ultrasound operation. The results show that the CO2 stripping rate by ultrasound is more than 3 times than heat only in the reboiler. A normalized specific energy consumption was defined based on the classic industrial case (4.2 kJ/kg CO2), and the normalized specific energy consumption 3.6 MJ/kg CO2 was deduced, showing 14% energy saving. Cost estimations have been conducted using Aspen Plus V9.0 and Aspen In-plant Cost Estimator for the industrial cases with/without the assistance of ultrasound. Total capture cost is 60.2 EUR/t CO2 and cost saving is 19% when the CO2 loading of the lean MEA solution can be further decreased to 0.20 mol/mol from 0.44 mol/mol assisted by ultrasound.