(343d) Amine-Blends Screening and Characterization for CO2 Post-Combustion Capture

The post combustion technology of carbon capture and storage (CCS) is gaining attention for reducing the CO₂ released from combustion processes into the atmosphere. Alkanolamines have been extensively studied for this purpose and the outcomes of previous works has divided alkanolamines into different types. Though the second order reaction rate constants, k₂ (m3.molâ??1.sâ??1) shows that MEA, 2MAE, 2DMAE, 2EAE have good kinetic properties, some others possess high CO₂ loading e.g. DAP, 3DMAPA, TMDAP, HMD all having CO₂ loading greater than 1. However, some other alkanolamines such as MDEA, 3DMA1P, TMPAD, have low heat of absorption below -60 kJ/mole.

This work studied the performance of novel amine blends in order to find a blend of alkanolamines which will possess all the required properties for efficient CO₂ capture. Following a previous experimental work which shows 2BAE as a suitable amine for carbon capture as it has a CO₂ loading of 0.69 mole CO₂/mole amine and a heat of absorption of -74.38kJ/mol of CO₂, 2BAE is selected alongside three tertiary amines (2DMAE, TMDAP, MDEA) and blends of changing percentages were prepared. The different blends were tested at 40°C for a total concentration of 30% weight amines and characterized using the solvents screening setup (S.S.S.) and Phosphoric acid titration (PAT) for CO₂ absorption experiment, Micro Reaction Calorimeter (URC) for heat of absorption measurements and the stopped-flow technique for the kinetic properties. For a total of 30% weight of aqueous amines, the 2BAE is varied as 0%, 5%, 10%, 15% and 30% while the respective tertiary amine makes the remaining part to make a total of 30%.

The results of this blends reveals that for all concentrations, the 2BAE + TMDPA blend has the highest CO₂ loading with 2BAE 5wt% / TMDPA 25wt, 2BAE 10wt% / TMDPA 20wt%, 2BAE 15wt% / TMDPA 15wt% having 1.21, 1.12 and 0.97 respectively while 2BAE 30wt% / TMDPA 0wt% is 0.69 mole CO₂/mole amine. On the other hand, the 2BAE + MDEA blend has the lowest CO₂ loading with 2BAE 5wt% / MDEA 25wt, 2BAE 10wt% / MDEA 20wt%, 2BAE 15wt% / MDEA 15wt% having 0.52, 0.54 and 0.57 respectively while 2BAE 0wt% / MDEA 30wt% and 2BAE 30wt% / MDEA 0wt% is 0.69 mole CO₂/mole amine. The heat of absorption of the 2BAE + MDEA is relatively high and increases as the concentration of 2BAE increases in the blend with a range from 66.58-91.60kJ/mole of CO₂.