Mass transfer coefficient of new amines

https://doi.org/10.1039/C7RA01352C

“Naami, et al.⁵⁹ have studied experimentally K_GCO2a_V for CO₂ absorption using a DEAB solution. They also investigated absorption using MEA, MDEA, DEAB, and blended solutions included MDEA–MEA and DEAB–MEA. The authors performed their experiments on an absorber column packed with DX-type structured packing (height 2.15 m; diameter 0.0275 m). It was concluded that the presence of MEA in the DEAB solution increased the K_GCO2a_V values. The authors also investigated the effect of the liquid flow rate on the K_GCO2a_V values, and found that by increasing it in a narrow range, K_GCO2a_V values increased rapidly. Nevertheless, the K_GCO2a_V values were unaffected by the gas flow rate for the above-mentioned amines. The absorption capacity and cyclic capacity between DEAB and MDEA were also compared in the study, and it was found that the new amine, DEAB, has a higher CO₂ absorption and cyclic capacity than MDEA, which causes a reduction in the amine circulation rate and energy consumption for amine regeneration. Fu, et al.⁶¹ have determined experimentally K_GCO2a_V for CO₂ absorption into a DETA solution. They performed the experiment on a random absorber column (packing height 1.14 m; column diameter 0.024 m) packed with Dixon rings which have a specific surface area of around 2400 m² m⁻³. Their results showed that the K_GCO2a_V values for DETA were higher compared with MEA, and the K_GCO2a_V values increased as the DETA flow rate, DETA concentration, and inlet temperature increased. However, the K_GCO2a_V values decreased when the CO₂ loading of DETA increased. Fu, et al.⁷⁶ have investigated the K_GCO2a_V parameter using a DETA solution. They performed the experiment on a structured absorber column (packing height 1.7 m; column diameter 0.028 m) packed with a DX packing which has a specific surface area of around 900 m² m⁻³. They compared the K_GCO2a_V values between DETA–CO₂ and MEA–CO₂ systems, and found that the K_GCO2a_V values of DETA were higher compared with MEA. In addition, they showed that by increasing the DETA flow rate, concentration, and inlet temperature, the K_GCO2a_V values increased. Nevertheless, the K_GCO2a_V values decreased as the CO₂ loading of DETA increased. Liang, et al.⁴⁴ have investigated the mass transfer performance of CO₂ absorption by a 1DMA2P solution. They obtained K_GCO2a_V for a structured absorber column (packing height 1.4 m; column diameter 0.028 m) packed with DX packing. The authors compared the K_GCO2a_V values for 1DMA2P–CO₂ with those for MEA–CO₂ and MDEA–CO₂ systems, and found that the K_GCO2a_V values of the MEA solution were higher compared with 1DMA2P and MDEA solutions. They ranked them as MEA > 1DMA2P > MDEA. In addition, they showed that by increasing the CO₂ loading for the three mentioned systems, the K_GCO2a_V values decreased. Following the study of Liang, et al.,⁴⁴ Wen, et al.⁷⁷ obtained the K_GCO2a_V values in an absorber column packed with Dixon rings for 1DMA2P–CO₂ system. They compared the K_GCO2a_V values for 1DMA2P–CO₂ with those for the MDEA–CO₂ system, and found that the K_GCO2a_V values of the new amine solution were higher compared with the MDEA solution. In addition, the effects of the gas flow rate, amine concentration, amine flow rate, CO₂ loading, and amine temperature on the K_GCO2a_V values were investigated and the results indicated that the K_GCO2a_V values increased with increasing amine concentrations and amine flow rates, but decreased with increasing CO₂ loading. The inert gas flow rate had little effect on the K_GCO2a_V values. For the amine temperature, the K_GCO2a_V values increased up to 323 K in temperature range of 303–333 K, and decreased as amine temperature went above 323 K. Xu, et al.³³ have conducted experiments for CO₂ absorption in a DEEA solution. The experiments were carried out for both random and structured packing columns, namely DX and Dixon rings. The authors obtained the K_GCO2a_V values in an absorber column with a 1.7 m packing height and a 0.028 m diameter. The effects of important process parameters on the K_GCO2a_V values were investigated. The results showed that the DEEA concentration, CO₂ loading, and liquid flow rate had the most pronounced effect on K_GCO2a_V, whilst the gas flow rate had a negligible effect. The authors compared the K_GCO2a_V values between MDEA–CO₂ and DEEA–CO₂ systems, and showed that the K_GCO2a_V values for DEEA were higher compared with the MDEA solution. They also showed that the DX-type structured packing enhanced the K_GCO2a_V values and cyclic capacity compared with the Dixon rings packing. Chen, et al.⁷⁸ have used the experimental design method including the Taguchi method to select blended amines (MEA–DEAE, MEA–MDEA, MEA–DIPA, and MEA + AMP) as promising solvents for CO₂ capture in a packed column (packing height 1.2 m; column diameter 0.05 m). The optimum points and effects of three key process parameters including the liquid flow rate, gas flow rate and amine concentration on the absorption rate and K_GCO2a_V were studied. Sixteen runs were carried out by the Taguchi method at four levels for four factors to obtain the response values (absorption efficiency, absorption rate, scrubbing factor, and K_GCO2a_V). In case of K_GCO2a_V, the values were obtained using a two-film model. The results of the study indicated that the gas flow rate and amine flow rate are significant parameters, while the type of amine and amine concentration showed little effect on the K_GCO2a_V values.”