Selection of Mixed Amines in the CO2 Capture Process

Abstract

In order to select the best mixed amines in the CO2 capture process, the absorption of CO2 in mixed amines was explored at the required concentrations by using monoethanolamine (MEA) as a basic solvent, mixed with diisopropanolamine (DIPA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ). Here, a bubble column was used as the scrubber, and a continuous operation was adopted. The Taguchi method was used for the experimental design. The conditional factors included the type of mixed amine (A), the ratio of the mixed amines (B), the liquid feed flow (C), the gas-flow rate (D), and the concentration of mixed amines (E). There were four levels, respectively, and a total of 16 experiments. The absorption efficiency (EF), absorption rate (RA), overall mass transfer coefficient (KGa), and scrubbing factor (<i>ϕ</i>) were used as indicators and were determined in a steady-state by the mass balance and two-film models. According to the Taguchi analysis, the importance of the parameters and the optimum conditions were obtained. In terms of the absorption efficiency (EF), the absorption rate (absorption factor) (RA/<i>ϕ</i>), and the overall mass transfer coefficient (KGa), the order of importance is D > E > A > B > C, D > E > C > B > A, and D > E > C > A > B, respectively, and the optimum conditions are A1B4C4D3E3, A1B3C4D4E2, A4B2C3D4E4, and A1B1C1D4E1. The optimum condition validation results showed that the optimal values of EF, RA, and KGa are 100%, 30.69 × 10−4 mol/s·L, 1.540 l/s, and 0.269, respectively. With regard to the selection of mixed amine, it was found that the mixed amine (MEA + AMP) performed the best in the CO2 capture process.

Integrated CO2capture and electrochemical upgradation: the underpinning mechanism and techno-chemical analysis

“…Based upon the attachment of amine groups within the molecule, it can be classified into five categories. 156 It is verified that different categories of amine have distinct advantages and drawbacks; (a) the primary amines like MEA have the advantages of a higher absorption rate for CO 2 and lower viscosity. However, they suffer from retarded absorption capacity for CO 2 (by stoichiometry 0.5 mole of CO 2 per mole of MEA) and higher heat capacity, vapor pressure, and solvent regeneration cost.…”

“…Chen et al have studied CO 2 absorption in mixed amines using the Taguchi method where MEA was used as a basic solvent and mixed with diisopropanolamine (DIPA), TEA, AMP, and PZ. 156 They used 16 sets of experiments and determined the conditional factors for CO 2 absorption; the type of mixed amines, the ratio of mixed amines, liquid feed flow, the gas flow rate, and the concentration of mixed amines. Based upon the outcomes from their designed experiment, it was concluded that the optimization condition is determined by the four different parameters; absorption efficiency, absorption rate, mass transfer coefficient and scrubbing factor.…”

A Review on CO2 Absorption using Chemical Solvents at Low and High CO2 Partial Pressure Conditions in a Packed Column

“…The reactivity of alkanolamines reduces as the number of hydrogen atoms decreases in the amine structures while the absorption capacity increases. Based on stoichiometry, the CO 2 loading capacity of primary amines is 0.5 mol of CO 2 /mol of amine [22]. It requires high energy for regeneration and is more corrosive compared to other groups of amines.…”

Flue-to-Fuel: Biomediated carbon capture and utilization of dilute CO2 gas streams to biomethane

“…The absorption is then followed by an energy-intensive regeneration of the amine by stripping at higher than 100 °C, where a pure CO2 gas can be released and collected. For the progress of optimizing amine scrubbing for post-combustion carbon capture, many different types of amines have been extensively screened for criteria like energy consumption for solvent regeneration, absorption performance, solvent resistance to degradation, solvent toxicity and volatility 8,9 . Among these, solvent regeneration and absorption efficiencies are considered the key criteria for assessing the performance of the amines due to the extensive energy penalty during the regeneration process of amine absorbents 9 .…”

“…The primary and secondary amines generally react rapidly to form stable carbamates that limit the CO2 loading to 0.5 moles of CO2 per mole of amine whereas tertiary and hindered amines exhibit slower kinetics and thus form ammonium bicarbonate via base-catalyzed hydration (Reaction 1). The utilization of tertiary and hindered amines, therefore, increases the CO2 loading capacity to one mole of CO2 per mole of amine 8 .…”