A cost effective pressure swing adsorption (PSA) process is under development for post-combustion CO2 capture from coal fired power plants. Several research groups from around the world are showing that PSA is still a viable option, as no separation process has emerged as a clear winner for CO2 capture. PSA is also attractive because it requires only electricity; it does not require any steam from the power plant. This project is being carried out with funding from DOE NETL and four collaborative partners:
The key challenge to the success of this project is two-fold: 1) an attrition resistant and low pressure drop structured adsorbent must be developed based on commercial zeolite that is compatible with the high velocities associated with shorter PSA cycle times, and 2) a PSA cycle configuration must be developed in concert with the structured adsorbent so that the resulting PSA process delivers an exceptional performance at reduced capital and operating costs. Since the rapid PSA concept is conceptually simple but difficult to implement, a select team has been assembled to carry out this ambitious project and demonstrate the feasibility of the PSA concept for CO2 capture at the bench scale. This team includes researchers from USC, W. R. Grace, Catacel, and Battelle.
To date, a key development includes the fabrication of a structured adsorbent that boosts a bed density of ~ 220 kg of adsorbent (including binder) per m3 of column. This coated, metal foil, parallel channel, corrugated structure was designed to fit snugly inside 1.5” ID by 18” long column using three, 6” sections. Prior to these cylindrical sections being inserted inside the SS column, the metal foil was coated with zeolite crystals to a thickness of ~ 50 microns and rolled to form the parallel channel, corrugated structure. The SS column was designed to fit directly into a novel 1-bed PSA system. This 1-bed system is capable of mimicking all the steps of a very sophisticated multi-bed PSA cycle schedule. This 1-bed system is being used to demonstrate the concentration of a 15 vol% CO2 in nitrogen mixture to over 95 vol% CO2 with a recovery exceeding 90%. Results obtained from this 1-bed system using a column filled with commercial zeolite beads will be compared directly with those obtained from the structured adsorbent column. This presentation will present the latest experimental results obtained from this effort.