Efficient regeneration of CO2-rich amine solutions by frequency-controlled microwaves

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K19859
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 64:Environmental conservation measure and related fields
• Research Institution: Kyushu University
• Principal Investigator: Tsubaki Shuntaro 九州大学, 農学研究院, 准教授 (90595878)
• Co-Investigator(Kenkyū-buntansha): 山田 秀尚 金沢大学, 先端科学・社会共創推進機構, 准教授 (60446408)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: マイクロ波 / 高周波 / 化学吸収法 / アミン吸収剤

Outline of Final Research Achievements

A large amount of energy is required to desorb CO2 by heating the absorbent solution in chemical absorption methods using amines. This study demonstrated the acceleration of CO2 desorption from amine and polyethyleneimine (PEI) absorbent solutions by molecular selective heating using microwaves. We measured the complex dielectric constants of amine and PEI aqueous solutions and found that the dielectric loss tangent (tan δ) was greatly improved by CO2 absorption. CO2-rich amines showed improved conductivity and increased tan δ due to the formation of carbamate and bicarbonate ions. We also demonstrated rapid temperature increases and accelerated desorption of CO2 by microwave (2.45 GHz) or radio-frequency (200 MHz) irradiation.

Free Research Field

触媒化学

Academic Significance and Societal Importance of the Research Achievements

大気中へのCO2排出抑制による地球温暖化防止のため、CO2分離回収における技術革新と、分離回収コストの飛躍的低減が求められる。アミン吸収液による化学吸収法は大規模実証試験が進み、実用化が進むCO2分離回収技術であるが、CO2を含んだリッチ吸収剤からのCO2の脱離と再生に多大なエネルギーを必要とする。本課題ではアミン吸収液に高選択的に作用するマイクロ波に着目し、吸収剤自身のマイクロ波吸収性の向上により、急速なCO2脱離を実現した。今後、簡便なCO2の回収方法として応用が期待される。