Hybrid hydrate processes for CO2/H2 mixture purification: A techno-economic analysis

In this work, hydrate based separation technique was combined with membrane separation and amine-absorption separation technologies to design hybrid processes for separation of CO2/H-2 mixture. Hybrid processes are designed in the presence of different types of hydrate promoters. The conceptual processes have been developed using Aspen HYSYS. Proposed processes were simulated at different flow rates for the feed stream. A comprehensive cost model was developed for economic analysis of novel processes proposed in this study. Based on the results from process simulation and equipment sizing, the amount of total energy consumption, fixed cost, variable cost, and total cost were calculated per unit weight of captured CO2 for various flow rates of feed stream and in the presence of different hydrate promoters. Results showed that combination of hydrate formation separation technique with membrane separation technology results in a CO2 capture process with lowest energy consumption and total cost per unit weight of captured CO2. As split fraction and heat of hydrate formation increases, the share of hydrate formation section in total energy consumption increases. When TBAB is applied as hydrate promoter, due to its higher hydrate separation efficiency, more amount of CO2 is captured in hydrate formation section and consequently the total cost for process decreases considerably. Hybrid hydrate-membrane process in the presence of TBAB as hydrate promoter with 29.47 US$/ton CO2 total cost is the best scheme for hybrid hydrate CO2 capture process. Total cost for this process is lower than total cost for single MDEA-based absorption process as the mature technology for CO2 capture. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, a hybrid process combining hydrate based separation, membrane separation, and amine-absorption separation technologies was designed for CO2/H-2 mixture separation. The results showed that the combination of hydrate formation separation technique with membrane separation technology resulted in a CO2 capture process with the lowest energy consumption and total cost per unit weight of captured CO2. The best scheme for hybrid hydrate CO2 capture process was the hybrid hydrate-membrane process in the presence of TBAB as hydrate promoter, with a total cost of 29.47 US$/ton CO2.