A Novel Rapid PSA System for Modular Oxygen Production

The capital cost and power requirements for current commercial oxygen separation processes are generally determined by the amount of oxygen required. For large-scale oxygen production, standard cryogenic air separation technologies offer the lowest production cost and energy requirements for oxygen. At oxygen production levels of less 500 tons/day TPD), the capital cost and energy penalty for cryogenic air separation become too high to compete with pressure swing adsorption PSA) or vacuum pressure swing adsorption VPSA) oxygen production systems. For an oxygen production rate of 10-50 TPD, the total cost of oxygen production for commercial PSA plants is about $200/ton with an electric power requirement of 300-500 kWh per ton of oxygen. Much lower capital costs and energy requirements are needed to support DOE’ modular gasification platform for small scale distributed power and chemical production from coal. Susteon Inc. is proposing a rapid cycle pressure swing adsorption process by using novel structured adsorbents to improve oxygen productivity of a conventional PSA system by almost by an order of magnitude. Structured adsorbents allow high gas throughput with low pressure drop and effectively exposes more gas/adsorbent contact resulting in higher mass and heat transfer and adsorbent utilization. We propose to incorporate conventional LiLSX materials into a structured continuous adsorbent structure—as opposed to the discrete nature of a beaded bed—to eliminate issues related to pressure drop, crush strength and dusting and improve adsorption kinetics. One key benefit of structured adsorbents is handling target flow rates within a much smaller footprint, which will reduce capex and opex. In Phase 1 of this project, working with our research institute partner, Georgia Tech, we plan to synthesize and screen a number of fibrous adsorbent structures. Adsorbents structures which exhibit superior performance will be tested in a lab-scale RPSA unit to measure their breakthrough and O2 separation performance to obtain necessary engineering design data. These results will enable a preliminary engineering design and a techno-economic analysis for a prototype pilot system to be designed, built, and tested in Phase 2. Successful demonstration at 50 kg/day scale will pave the way for the design and deployment of a 10-50 ton/day commercial modular system to meet the DOE goal for distributed power production of 1 to 5 MW, in collaboration with our industrial partner, Praxair. The anticipated benefits of the proposed technology will be development of a modular oxygen. Development technology for modular gasification and other applications, including medical oxygen supply, oxygen for ozone production, refining, smelting, water purification, wastewater treatment, etc. Key factors for market acceptance and penetration of this technology will be its compact size, robustness, and low cost of oxygen production.