Gas fired power plants provide about 46% of current electricity in the UK and are responsible for 35% of CO2 emissions. With this regard, Carbon Capture and Storage retrofit represent an attractive option for Combined Cycle Gas Turbine (CCGT) plants. The key challenge in post combustion capture from gas fired power plants is due to the low CO2 concentration in the flue gas, approximately 3 to 7% by volume. This means that conventional amine processes will results in a relatively high energy penalty while novel adsorbents and adsorption processes have the potential to improve the efficiency of separation. Due to the low CO2 concentration pressure swing adsorption processes cannot be considered as a valid option for rapid regeneration of the adsorbents. This means also that the characteristics of the adsorbents must be very different from the materials selected for the equivalent separation process from coal fired power plants. High selectivity will be necessary to achieve relatively high CO2 uptake at low partial pressures, which means that the separation process should be based on either very strong physisorption or chemisorption with thermal regeneration. From the process point of view the key challenge is to develop a process able to achieve rapid thermal swings of the order of a few minutes, which is over an order of magnitude faster than traditional Thermal Swing Adsorption (TSA) fixed bed processes.
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