High pressure solvent/vacuum swing adsorption hybrid capture system for gas turbine power plants

With the increasing awareness towards global carbon dioxide (CO₂) emissions, carbon capture and storage (CCS) has been proposed as part of the solution to reduce the effect of climate change. To help bring about CCS a high-pressure (>30bar) solvent absorption/vacuum swing adsorption (VSA) hybrid capture system has been developed to reduce the energy penalty associated with the post combustion carbon capture of a Natural Gas Combined Cycle (NGCC). The system uses VSA system to create a CO₂ rich stream which is recirculated around to the inlet air to the gas turbine. The compressed gases are then sent to a solvent capture system to recover the CO₂. The CO₂ free gas is used to combust the fuel in the GT combustor and expanded to generate power. The solvent used in this study is a 30wt% K₂CO₃ solvent chosen for its stability at high temperatures. The high pressure gas increases the partial pressure of CO₂ enhancing the driving force for mass transfer. Using multi-objective optimisation, the VSA and solvent capture conditions were optimised at different capture rates. At a capture rate of 75% the VSA/solvent hybrid is able to reduce the energy penalty by 3.6% points from 10.5% for the base case solvent system to 6.9%.