Experimental study on CO₂ capture by MEA/n-butanol/H₂O phase change absorbent

Area of Science:

• Chemical Engineering
• Carbon Capture Technologies
• Separation Processes

Background:

• Traditional Monoethanolamines (MEAs) for CO2 capture require high regeneration energy.
• CO2 Phase Change Absorbents (CPCAs) offer reduced energy consumption by selectively desorbing a CO2-rich phase.
• Existing CPCAs have limitations in absorption capacity, viscosity, and phase volume.

Purpose of the Study:

• To propose and evaluate a novel CPCA, MEA/n-butanol/H2O (MNBH), for efficient CO2 capture.
• To compare the performance of MNBH against conventional MEA-based absorbents.
• To assess the potential of MNBH for reducing regeneration energy and enhancing CO2 absorption.

Main Methods:

• Formulation of a novel CPCA with a specific MEA/n-butanol/H2O composition.
• Experimental determination of CO2 absorption capacity at various conditions.
• Measurement of CO2 desorption efficiency and regeneration energy consumption.
• Evaluation of CO2 recycling capacity and performance in simulated flue gas.

Main Results:

• The MNBH absorbent achieved a maximum CO2 absorption capacity of 2.5227 mol CO2/mol amine at a 3:4:3 mass ratio.
• CO2 desorption efficiency reached 89.96% at 120 °C, with regeneration energy consumption of 2.6 GJ/tCO2 (35% lower than 30 wt% MEA).
• At a 3:6:1 mass ratio, MNBH exhibited a CO2 recycling capacity of 4.1918 mol CO2/L, 76% higher than 30 wt% MEA.
• The MNBH absorbent reduced desorbent volume by approximately 50% and showed good CO2 absorption from flue gas.

Conclusions:

• The novel MNBH CPCA demonstrates superior CO2 absorption capacity and significantly lower regeneration energy requirements.
• MNBH offers advantages over conventional MEA systems, including reduced viscosity, smaller CO2-rich phase volume, and enhanced recycling capacity.
• This developed phase change absorbent presents a promising, energy-efficient solution for CO2 capture from industrial flue gases.