A comprehensive multidisciplinary investigation on CO₂ capture from diesel engine

Area of Science:

• Environmental Science
• Chemical Engineering
• Materials Science

Background:

• Diesel engines are significant anthropogenic sources of atmospheric carbon dioxide (CO2), contributing to climate change.
• Effective post-combustion carbon capture (PCC) systems for diesel engines are underdeveloped.
• Minimizing CO2 emissions from diesel engines is crucial for environmental protection.

Purpose of the Study:

• To investigate the efficacy of post-combustion carbon capture (PCC) for diesel engine emissions.
• To evaluate various absorbents, including aqueous ammonia (AQ_NH3), monoethanolamine (MEA), N,N-dimethylethanolamine (DMEA), and an ionic liquid (C2mim BF4), for CO2 capture.
• To analyze the reaction mechanisms of CO2 absorption using computational methods.

Main Methods:

• Experimental testing of CO2 capture on direct injection diesel engine exhaust at five brake power settings.
• Utilizing blends of AQ_NH3, MEA, DMEA, and C2mim BF4 as absorbents.
• Employing first-principles density functional theory (DFT) for geometrical, energetical, MESP, frontier molecular orbitals, and NBO analysis of reaction mechanisms.

Main Results:

• A blend of 67% AQ_NH3 and 33% MEA achieved a maximum CO2 absorption efficiency of approximately 97%.
• The AQ_MEA blend demonstrated 96% CO2 absorption efficiency.
• A blend of AQ_NH3, DMEA, and C2mim BF4 ionic liquid showed 94% CO2 absorption efficiency.

Conclusions:

• Specific blends of aqueous ammonia and amines, along with ionic liquids, are highly effective for post-combustion CO2 capture from diesel engines.
• The developed PCC methods offer a promising solution for reducing CO2 emissions from diesel engine exhaust.
• Computational analysis provides insights into the chemical mechanisms governing CO2 absorption by the tested absorbents.