Abstract
There exists a portfolio of technologies that can be deployed for post-combustion CO2 capture. Each technology performs optimally at specific conditions, which will hardly coincide with exact industrial applications. Hybrid processes combine two (or more) technologies to perform the CO2 separation. The goal is to design processes that allow each technology in the hybrid configuration to operate optimally, resulting in cost-effective CO2 capture solutions. This study explores the feasibility of realizing this potential by mapping the techno-economic potential of selected hybrid processes across a wide spectrum of CO2 concentrations, plant scales and energy system contexts. The four hybrid processes considered are: vacuum pressure swing adsorption (VPSA)-membrane, membrane-VPSA, VPSA-CO2 liquefaction and membrane-CO2 liquefaction. A consistent techno-economic optimization framework is developed to identify the optimal process characteristics and associated minimum cost for each case considered. The performances are compared against those of conventional standalone capture technologies – VPSA, membranes and chemical absorption. Hybrid processes show promising results for medium-to-high CO2 concentrations (≈13–30 % CO2), where costs in the range 40–70 €/tCO2 appear achievable. However, even when different levels of electricity price and emission intensity are considered, chemical absorption and membranes remain the two most cost-efficient processes in most of the cases considered with hybrid processes at least 15 % more expensive. The material properties of membranes and adsorbents proved to have a significant impact on the expected performance. The sensitivity analysis showed how changing material properties assumption within relevant boundaries could modify the relative performance and advance hybrid processes, such as VPSA-membrane, as potentially attractive solutions, with the potential to decrease cost of >10 % at specific industrial conditions.