A Novel Approach to Post-Combustion Carbon Capture Processes in Natural Gas Plants By Reduction of Solvent Regeneration Time

Abstract

Carbon Capture processes have been utilized in various sectors, but limitations in its large parasitic load have been observed in its use in Natural Gas Process Plants, and that is mostly associated with the energy penalty incurred during its processes. The energy penalty is mainly caused by the solvent regeneration in the stripper column, the CO2 compression process, and the low amount of CO2 levels in the combustion flue gas, which is usually less than 15% (7-14 % for coal-fired and as low as 3% for gas-fired). This research work, therefore, has the objective of solving the challenges of solvent regeneration time in the stripper column, as the packing arrangement, corrugation angle, and crimp height can influence the capture efficiency through the solvent. Aspen HYSYS was adopted for modeling the absorption rate through the stripper column in order to understand the hydrodynamic phenomenon in absorbers using solid absorbents under plug flow and well-mixed flow conditions. The rate fraction was analyzed at various process configurations and staged regeneration simulation processes in a packed column considering enthalpy changes at both gas and liquid phases. The results showed a 20% reduction in the solvent regeneration time, as against existing processes & technologies. It was observed that operating at a lower circulating rate results in a lower utility requirement on the reboiler hence increasing the circulation flow rate, which has little to no effect on the condenser utility. And this additionally led to a reduction in the energy penalty, as low-pressure steam was used as the energy input for the solvent regeneration process, thus posing a significant efficiency penalty. In conclusion, the modeling by the process optimization and modification of the post-combustion carbon capture plant reduced the regeneration energy requirements. Novel/Additive Infirmation: The solvent solution flowrate in the absorber was optimally considered with various lean CO2 solvent loadings in order to achieve higher CO2 capture and removal efficiency.