Browsing by Author "Goberman, Daniel"
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Item Metal Oxide Sorbent Deactivation Study(49th International Conference on Environmental Systems, 2019-07-07) Guerrero, Sandra; Auman, James; Boyle, Robert; Chase, Thomas; Goberman, Daniel; Macias, Brian; Nalette, TimothyThe metal oxide (METOX) CO2 scrubber technology was developed by UTAS in the early 1990s as a replacement for non-regenerable LiOH canisters used in NASA’s Extravehicular Mobility Unit (EMU) system or space suit. METOX has been the main CO2 scrubber since 1998, utilizing a silver oxide sorbent and alkali metal salts to capture metabolically produced CO2 in the form of silver carbonate which is thermally regenerated to silver oxide after each use. In 2015 a performance reduction in one of the Metox canisters was observed and while the system still met the established CO2 removal requirements, the causes leading to the performance reduction have not been clearly justified. However, one of the most likely reasons is suspected to be the deactivation or degradation of the sorbent material within the system. Therefore, United Technologies Aerospace Systems, (UTAS) in collaboration with United Technologies Research Center (UTRC), is conducting a study to investigate the potential sorbent degradation mechanisms. The preliminary testing will focus on the identification of potential contaminants in addition to any changes in crystalline structure, morphology and surface area of sorbent samples extracted from the “as returned from orbit” METOX canisters and comparing the results to a prepared baseline Metox sorbent sample. Additionally, the effect of thermal desorption at a temperature above the nominal regeneration temperature will be evaluated on these sorbent samples while collecting the desorbed gases for further trace contaminant analysis. Potential oxidation of gas phase contaminants and implication on reaction kinetics will also be addressed. Some of the analytical techniques used in the study will include: X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with Electron Dispersive Spectroscopy (EDS), Thermal Desorption with Gas Chromatograph Mass Spectroscopy (GC/MS), and Brunauer-Emmett-Teller (BET) for surface area determination. This paper summarizes the preliminary test results, and discusses potential mechanisms of sorbent degradation.Item Poisoning Evaluation of On-Orbit Sabatier Assembly(2020 International Conference on Environmental Systems, 2020-07-31) Carpenter, Joyce; Yu, Ping; Woods, Julius; Goberman, Daniel; Galvin, Lynda; Garr, John; Ulrich, BettyLynnThe Sabatier Assembly (SA) P/N SV1015510-1 was designed by Collins Aerospace to partially close the life support loop on ISS by reacting two waste gases (carbon dioxide and hydrogen) to form water (and waste methane). Waste CO2 is recovered from cabin air by the Carbon Dioxide Recovery Assembly (CDRA) and waste H2 comes from the Oxygen Generation System (OGS). By recycling these waste gases, this reduces the need to launch excess water, which is costly. The SA was successfully launched in 2010, and was in operation from June 2011 through October 2017. During that period of time, Sabatier produced 1081 liters of water. In 2018, the Sabatier on-orbit unit began to show significant signs of degradation in the reactor. To keep the system operating, this required increasingly involved procedures to restart the reaction after a shutdown. Eventually, the decision was made to shut down the Sabatier Assembly and to return it to Collins Aerospace for TT&E (Test, Teardown and Evaluation) with the goal of providing an upgraded system to support Exploration demonstration hardware on ISS. This paper reports the poisoning evaluation results of the catalyst reactor.