(715a) Nano-& Micro-Engineered Adsorption Technology for Rapid CO2 Adsorption/Regeneration

CO2 capture from flue gases presents an un-precedent challenge to the separation technology due to low-cost requirement, high gas flow rate, and low head pressure. Capturing CO2 in a short contact time and regenerating the saturated adsorbent rapidly have direct impact on capital and operation costs. A multi-scale material and process engineering approach will be described in this presentation. First, a self-assembly method is used to prepare nano-sized zeolite crystals and enhance intrinsic adsorption/desorption kinetics of the zeolite adsorbent, since the micro-pore diffusion rate has second order dependence on the crystal size. Second, the parent zeolite is modified by ion exchanges to reduce the heat of adsorption and increase the CO2 adsorption capacity, particularly in the presence of moisture. Third, the nano-sized adsorbent powder is incorporated into a micro-channel adsorption bed for practical adsorption/regeneration operation. The micro-structured bed provides high adsorbent loading (>50 wt.%), very low ?xP for the gas to flow through, little dead or stagnant volume, and fast mass and heat transfer between the channel flow and external surface of the adsorbent particle. Integration of the innovations made in the above three design scales can lead to reduction of the adsorbent bed size by an order of magnitude compared to the conventional packed bed. Scope process design and economics analysis suggests it is possible to reduce the CO2 capture cost by 65% compared to the amine scrubbing process.