Dynamic Adsorptive Carbon Capture in Power-to-Gas Plants

Energy transition can be addressed in the very near future with low investment costs by utilizing already-available technologies and infrastructures. In this regard, among innovative energy carriers, green synthetic methane can tackle the issue by taking advantage of natural gas facilities. Power-to-gas systems enable methane synthesis by combining electrolytic hydrogen and captured carbon dioxide. This work investigates the adsorptive carbon capture in the context of a power-togas system. Carbon dioxide is trapped onto the porous surface of a packed bed by adsorption and is then released during bed regeneration. The alternating process operation is analyzed by means of a dynamic model capable of reproducing both adsorption and desorption. The other system components are dynamically modeled as well to simulate their interaction during the cyclic operation. The whole cycle is analyzed. Bed regeneration by means of a hydrogen purge flow is evaluated considering the possibility of utilizing the mixture of hydrogen and desorbed carbon dioxide as reactants in a subsequent catalytic methanation process. The boundary limits for the pressure of the hydrogen purge source are identified in order to obtain the desired reactants proportion. Regarding adsorption, different post-combustion flue gases are evaluated as carbon dioxide sources from a plant-management perspective.