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.