Energy Efficient Plasma-Assisted Catalytic Oxidation of Carbon Monoxide

Some isolated or poorly ventilated spaces within the U.S. fleet submarines can benefit from local removal of carbon monoxide (CO), which is a very toxic and flammable gas. This SBIR topic seeks to develop an energy-efficient, compact, portable, stable, and stand-alone system to prevent the build-up of CO in such isolated and poorly ventilated spaces. Requirements formulated for such a system are very stringent: the proposed portable system will continually monitor its local space and activate when necessary (i.e., greater than 50 ppm CO) to continuously remove the CO until a local concentration of 5 ppm is attained. The airflow through the CO removal system must be at least 100 cubic feet per minute (cfm). The system must achieve a 95% removal rate over a temperature range of 15°C to 25°C and relative humidity in the range of 50%-80%. The confined spaces do not have access to cooling water but will have access to electrical power (115 VAC, 100 Watt maximum) for running a fan, operating a CO sensor, and all other system equipment. The system must operate for 10,000 hours without requiring maintenance when 115 VAC power is available. Battery backup must be included to allow the system to remove CO for one hour if 115 VAC electrical power is not available. The final target maximum system weight and volume are 50 pounds (lbs.) and 2 cubic feet, respectively. Continuous oxidation of 50 ppm CO admixture in airflow of at least 100 cfm with a 95% removal rate at room temperature using less than 100 Watt is a challenging task. This task will be resolved using a combination of a catalyst based on gold nano-particles (GNPC) and nano-second pulsed non-thermal plasma (NTP). GNPC by itself loses oxidation efficiency relatively quickly: by 20% in about 10 minutes time on stream (TOS) and by 50% in about 8 hours TOS. It was demonstrated that nano-second pulsed NTP can regenerate GNPC in 5 min. after 70 min. TOS. The novelty of the proposed approach is the use of un-interrupting catalyst regeneration during TOS with the help of nano-second pulsed NTP. R&D efforts during Phase I will allow determining the optimal conditions for CO oxidation by GNPC and for un-interrupting catalyst regeneration. These conditions will then be used during a week-long operational test of the experimental system. The results of this test will be proof of concept for a new method of catalyst performance stabilization, which will be a foundation for the prototype development during Phase II. The Phase I Option will provide additional proof of concept by a two-months-long test of the performance of the developed experimental plasma-catalytic system. Additionally, the Phase I Option will provide time and funding for the initial design of a system prototype, which includes a more powerful pulsed power supply, and for developing a detailed plan of how to construct the prototype in Phase II taking into account special DoN requirements.