چكيده به لاتين
Deep eutectic solvents (DESs) are a new generation of green solvents that are considered as a promising CO2-capturing candidate owing to their desirable properties, good stability, and environmental-friendly features. Here, we developed novel hybrid solvents based on DESs for CO2 separation from a simulated flue gas flow. Deep eutectic solvents: Choline Cloride-Monoethanolamine (ChCl-MEA), Glyceline, and piperazine activated Glyceline (Glyceline/Pz) were added to the Diethanolamine (DEA) solution in the concentration range of 10-30 wt%. The CO2 absorption performance of the DES-DEA hybrid solvents was studied from the solubility and mass transfer point of view. Hydrodynamic studies revealed that the addition of DES results in a smaller bubble Sauter mean diameter. Moreover, partially replacing water with ChCl-MEA or Glyceline/Pz increased the CO2 capture capacity, effective time, empirical enhancement factor, and overall mass transfer coefficient. On the contrary, with increasing Glyceline concentration, the enhancement factor and overall mass transfer coefficient decreased under the studied operating conditions, although the CO2 solubility did not change. Moreover, 13C Nuclear Magnetic Resonance (NMR) analysis was used to characterize carbon-based species in DES-DEA systems before and after CO2 absorption. Finally, the results of Thermogravimetric Analysis (TGA) measurements demonstrate that the addition of glycerol-based DESs makes more stable hybrid solvents which could be regenerated feasibly.
Energy-efficient solvents with favorable thermodynamic properties that offer significantly low regeneration energy to the state – of – the – art CO2 capture technologies are typically limited by slow reactivity with CO2. To compensate for low absorption rates, Herein, we report that the nonporous hypercrosslinked polymeric networks (HCPs) as rate promoters are capable of drastically accelerating CO2 absorption in N-methyldiethanolamine (MDEA) and DEA – Glycerol sorbents. It is a new topic toward the application of hypercrosslinked polymeric networks. Four hypercrosslinked polymers were synthesized from monomers: benzene (HCP-B), polystyrene (HCP-S), benzyl chloride (HCP-BC), and carbazole (HCP-C), and then the novel slurry solvents were prepared by suspending HCPs in amine-based solutions.
Benefiting from the inherent properties, HCP-S and HCP-B increased the overall rates of CO2 absorption in MDEA solution by 253 and 130%, respectively, compared to the blank MDEA. The effect of temperature and amine concentration on the promoting performance of HCP-B was investigated. HCP-B promotes CO2 sorption in the whole temperature range from 25 to 80 ℃, and at MDEA concentrations of 2 to 4 molar. Moreover, 13C NMR analysis was used to confirm the promoting effect of the network on CO2 sorption, and a possible mechanism was surveyed. Moreover, the slurry solvents DEA – Glycerol – HCP have been investigated as the efficient sorbents for post-combustion CO2 capture. HCP-B, HCP-S, HCP-BC, and HCP-C were added to the semi-aqueous DEA – Glycerol solvents to increase the CO2 absorption rate under the low partial pressures of CO2. Among the studied networks, HCP-C showed the best performance toward the rate enhancement. The results revealed that with increasing the Glycerol and DEA concentration and the gas flow rate, the rate enhancements in the presence of HCP-C increases.