Browsing by Author "Wambolt, Spencer R."
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Item Increased Oxygen Recovery from Sabatier Systems Using Plasma Pyrolysis Technology and Metal Hydride Separation(45th International Conference on Environmental Systems, 2015-07-12) Greenwood, Zachary W.; Abney, Morgan B.; Perry, Jay L.; Miller, Lee A.; Dahl, Roger W.; Hadley, Neal M.; Wambolt, Spencer R.; Wheeler, Richard R.State-of-the-art life support carbon dioxide (CO2) reduction technology is based on the Sabatier reaction where less than 50% of the oxygen required for the crew is recovered from metabolic CO2. The reaction produces water as the primary product and methane as a byproduct. Oxygen recovery is constrained by the limited availability of reactant hydrogen. This is further exacerbated when Sabatier methane (CH4) is vented as a waste product resulting in a continuous loss of reactant hydrogen. Post-processing methane with the Plasma Pyrolysis Assembly (PPA) to recover hydrogen has the potential to dramatically increase oxygen recovery and thus drastically reduce the logistical challenges associated with oxygen resupply. The PPA decomposes methane into predominantly hydrogen and acetylene. Due to the highly unstable nature of acetylene, a separation system is necessary to purify hydrogen before it is recycled back to the Sabatier reactor. Testing and evaluation of a full-scale Third Generation PPA is reported and investigations into metal hydride hydrogen separation technology is discussed.Item Plasma Extraction of Oxygen from Martian Atmosphere(45th International Conference on Environmental Systems, 2015-07-12) Wheeler, Richard R. Jr.; Hadley, Neal M.; Wambolt, Spencer R.; Holtsnider, John T.; Dewberry, Ross; Karr, Laurel J.In support of NASA’s In-Situ Resource Utilization (ISRU) objectives an SBIR Phase 1 effort has demonstrated conceptual feasibility of a novel Plasma Extraction of Oxygen from Martian Atmosphere (PEOMA) technology. Extraction of oxygen from the abundant carbon dioxide present on Mars (96% atmospheric composition) is an important goal in preparation for manned missions to the planet. Oxygen is not only a fundamental reactant with high specific energy chemical fuels such as hydrogen and methane, it, along with water, are clearly two of the most critical resources for life support. Using microwave plasma techniques to decompose CO2 into CO and 1⁄2O2, coupled with subsequent O2 separation, a PEOMA robotic processor located on the Martian surface would allow oxygen to be stockpiled for later use during manned exploration near this location. This investigative work has succeeded at validating effective molecular dissociation in a carbon dioxide plasma, with no solid carbon formation. Using innovative standing wave microwave plasma reactor designs, ubiquitous 2.45 GHz microwave technology was employed to demonstrate up to 86% single pass carbon dioxide decomposition.Item Third Generation Advanced PPA Development(44th International Conference on Environmental Systems, 2014-07-13) Wheeler, Richard R.; Hadley, Neal M.; Wambolt, Spencer R.; Abney, Morgan B.A Phase 3 advanced development project has culminated in the design and fabrication of a third generation Plasma Pyrolysis Assembly (PPA), recovering up to 75% of the hydrogen currently lost as methane in Sabatier reactor effluent. By doing so, the PPA helps to minimize life support resupply costs for extended duration missions. The 3-year development effort, completed as part of NASA’s Atmosphere Revitalization Resource Recovery task, has resulted in a fully functional stand-alone 5-CM (crew member) capacity PPA prototype. This device, recently delivered to NASA-MSFC, embodies the current state of the art in microwave methane plasma pyrolysis. At 90% single pass conversion the third generation PPA shows a ten-fold increase in processing rate capability over the first generation PPA, improves microwave to chemical energy conversion efficiency by three-fold (to 22%), and maintains a low residual carbon production rate at 0.20% of carbon from converted methane. Additional third generation technology advancements include increased process autonomy, incorporation of a regenerative residual carbon trap and in-situ reactor cleaning using CO2 plasma oxidation. Future development work must focus on fully autonomous operation, increased carbon trap capacity, more complete regeneration and improved process energy efficiency.