Browsing by Author "Shah, Malay"
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Item Demonstration of Plasma Assisted Waste Conversion to Gas(49th International Conference on Environmental Systems, 2019-07-07) Meier, Anne; Shah, Malay; Quinn, Katerina; Engeling, KennethThe NASA Science Technology Mission Directorate Center Innovation Project at Kennedy Space Center funded a one year investigation for the development of a DC plasma torch to test the conversion of solid and liquid mission waste to gas. The volume reduction of mission waste is needed to advance waste processing for vent gases on board space vehicles and space habitats for long duration missions. The selected plasma torch operated with an input voltage of 120 VAC and a plasma pilot arc power of approximately 400 W using air as a baseline carrier gas. To date, the team has demonstrated early concepts of plasma assisted waste conversion of the following materials: cotton hygiene material, astronaut clothing, plastics (i.e. polyethylene and nylon), astronaut food packaging, paper, fecal waste simulant, and degrading plant matter (i.e. inedible biomass waste). The reactions took place in a quartz cylindrical test cell, where waste was loaded into a quartz crucible and monitored with optical video. The initial reactions included a multi-stage process that was primarily plasma combustion. The reaction product gas was qualitatively and quantitatively analyzed with a gas chromatograph and Fourier transform infrared spectroscopy instrument. The initial results of the system show the volume reduction from solid to gas in the form of useful products such as carbon monoxide, carbon dioxide, methane and light hydrocarbons. This paper will discuss the project development and results regarding waste conversion, power performance and volume reduction for a plasma space waste processing system.Item Development of a Micro-Scale Plasma Arc Gasification System for Long Duration Space Mission Waste Processing(47th International Conference on Environmental Systems, 2017-07-16) Meier, Anne; Thakrar, Prital; Shah, Malay; Johnson, Thad; Bayliss, Jon; Hintze, Paul; Gibson, Tracy; Captain, JamesThe NASA Space Technology Mission Directorate Center Innovation Fund at Kennedy Space Center (KSC) funded a one year investigation for the development of a micro-scale plasma arc gasification system for waste repurposing on long duration space missions. The reuse of discarded materials on a long duration or planetary mission is a critical component in reducing overall mission mass and creating useful commodities like fuel, water and repurposed construction materials. Plasma arc gasification converts the majority of organic waste into a synthesis gas (syngas), consisting primarily of hydrogen, carbon monoxide and carbon dioxide, and inorganic waste into a solid slag material that can be used as a construction aggregate. Plasma arc gasification had not been previously investigated for space applications, and potentially provides a cleaner product than other waste processing methods. The micro-scale plasma arc gasification system was designed, fabricated, and tested at KSC with a commercial plasma torch. This paper will discuss the project development and results regarding the use of plasma at low power and the challenges of plasma arc gasification for small scale waste conversion. Designing the power supply was the main challenge in this project. Although this plasma torch was successfully operated for short periods of time, the power supplies did not allow for low power operations over long periods of time.Item Investigating Waste Preparation Methods for Trash-to-Gas Technologies(51st International Conference on Environmental Systems, 7/10/2022) Shah, Malay; Pitts, Ray; Benson, Morgan; Gleeson, JonathanTrash-to-gas technologies show promise in addressing the need for a sustainable waste management system onboard long-duration space habitats. However, a clear understanding on how the initial preparation and transport of waste into the reaction zone can affect the overall conversion efficiency must be realized. Factors such as the waste size, moisture content, and packing density can have significant impacts on the reactor performance. The goal of this study was to leverage current state-of-the-art preparation and delivery mechanisms to develop a concept for a full-scale, microgravity compatible system that can prepare and deliver waste that enhances the overall solid-to-gas conversion of existing trash-to-gas technologies. An extensive literature review was conducted to select potential candidates for such a system. High-performing candidates were tested in the laboratory environment using a mixed waste stream (organics and inorganics) to determine how these methods affect the total syngas production in a combustion reactor. This work will help lay the framework for implementation in a full-scale trash-to-gas system on exploration class space missions.Item Low-Pressure Plasma Assisted Waste Conversion(50th International Conference on Environmental Systems, 7/12/2021) Engeling, Kenneth; Shah, Malay; Tessema, MisleThe commercialization of space and advancement of modern technologies have led to expected human presence beyond Low Earth Orbit. With this, alternative technologies for the reusability of human-generated waste streams becomes necessary. An interesting such technology is the conversion of waste to gas via the employment of plasma and plasma technology. Low power plasma-assisted waste conversion technology has not been greatly explored under space-like conditions. Presented in this report is a DC plasma discharge operating under one kilowatt without any feedstock gas flow and in rough vacuum conditions. Materials of interest used in the study are typical of astronaut waste streams such as cloth, food packaging, plastics, and cleaning materials. The removal of a feedstock gas explores gasification percentages without the use of a consumable in the previously explored plasma torch setup. The average solid to gas conversion in the highly exploratory setup was around 36%. This number is expected to be greatly increased with electrode position optimization and waste stream pre-processing. The by-product gases were captured and analyzed using gas chromatography which showed generation of H2, CO2, CO, C2H4, CH4, H2O, and other hydrocarbons. This text reports on the plasma gasification percentages, temperature and pressure profiles, liquid condensate analysis, reaction mechanisms, and viability of a low pressure, low power plasma for waste conversion without a feedstock gas.Item Mars Atmospheric Conversion to Methane and Water: An Engineering Model of the Sabatier Reactor with Characterization of Ru/Al2O3 for Long Duration Use on Mars(47th International Conference on Environmental Systems, 2017-07-16) Meier, Anne; Shah, Malay; Hintze, Paul; Petersen, Elspeth; Muscatello, AnthonyThe Atmospheric Processing Module (APM) is a Mars In-Situ Resource Utilization (ISRU) technology designed to demonstrate conversion of the Martian atmosphere into methane and water. The Martian atmosphere consists of approximately 95% carbon dioxide (CO2) and residual argon and nitrogen. APM utilizes cryocoolers for CO2 acquisition from a simulated Martian atmosphere and pressure. The captured CO2 is sublimated and pressurized as a feedstock into the Sabatier reactor, which converts CO2 and hydrogen to methane and water. The Sabatier reaction occurs over a packed bed reactor filled with Ru/Al2O3 pellets. The long duration use of the APM system and catalyst was investigated for future scaling and failure limits. Failure of the catalyst was detected by gas chromatography and temperature sensors on the system. Following this, characterization and experimentation with the catalyst was carried out with analysis including x-ray photoelectron spectroscopy and scanning electron microscopy with elemental dispersive spectroscopy. This paper will discuss results of the catalyst performance, the overall APM Sabatier approach, as well as intrinsic catalyst considerations of the Sabatier reactor performance incorporated into a chemical model.Item Microgravity Experimentation of Long Duration Space Mission Waste Conversion(49th International Conference on Environmental Systems, 2019-07-07) Shah, Malay; Meier, Anne; Toro Medina, JaimeThe NASA Orbital Syngas / Commodity Augmentation Reactor (OSCAR) project is a 2 year project that aims to reduce risk of a space waste conversion system by demonstrating a microgravity reactor to advance NASA’s Trash-to-Gas efforts for mission waste reduction and conversion. On long duration deep space missions, humanity will be required to increase sustainability and efficiency on missions, which can be done by effectively managing logistical waste. The reuse of discarded materials on a long duration, deep space mission will reduce overall mission mass, increase usable spacecraft and habitat volume and improve mission reliability and robustness. On a 1 year mission, a four person crew will produce approximately 2,500 kg of waste materials consisting of food packaging, used clothing, hygiene items, human waste, life support system supplies, and other crew supplies. Repurposed waste can be safely vented off of a spacecraft in the form of an inert gas or useful material can be recovered such as fuel, air, water, and even feedstocks for spacecraft construction and repair. This paper will discuss the project development and results regarding the demonstration of a test article that will undergo microgravity tests at NASA’s 2.2-second Drop Tower, the Zero Gravity Research Facility, and on a several-minute commercial suborbital flight. Waste processing reactors will behave differently in reduced gravity with regards to the thermochemical process (ex: combustion), gas mixing, drying, solid entrainment behavior, and ash formation. The behavior of these situations in microgravity will be observed with OSCAR and results will be used to decide the appropriate method to model the system and to help guide the design of how air – or other oxidant – should be introduced into the hearth zone for optimum material conversion.Item Sabatier System Design Study for a Mars ISRU Propellant Production Plant(48th International Conference on Environmental Systems, 2018-07-08) Hintze, Paul; Meier, Anne; Shah, MalayAs NASA looks towards human missions to Mars, an effort has started to advance the technology of a Mars ISRU Propellant Production Plant for a flight demonstration. This paper will present a design study of the Sabatier subsystem. The Sabatier subsystem receives CO2 and H2 and converts them to CH4 and H2O. The subsystem includes the Sabatier reactor, condenser, thermal management, and recycling system if required. This design study will look at how the choice of reactor thermal management and recycling system affect the performance of the overall Sabatier system. Different schemes from the literature involving single or cascading reactors will be investigated to see if any provide distinct advantages for a Mars propellant production plant.Item Space Mission Waste Conversion Experiments at the Zero Gravity Facility(2020 International Conference on Environmental Systems, 2020-07-31) Meier, Anne; Shah, Malay; Toro Medina, Jaime; Rinderknecht, David; Pitts, RayHumans are required to increase sustainability and efficiency on missions, which can be done in part by effectively managing logistical waste. Repurposed waste can be safely vented in the form of an inert gas off of a spacecraft, or useful material can be recovered, such as syngas (propellant), air, water, raw material for construction and repair feedstocks or replacement parts. The NASA Orbital Syngas / Commodity Augmentation Reactor (OSCAR) project has completed a 2 and 5 second microgravity test campaign at the Glenn Research Center Drop Tower and Zero Gravity Facility to demonstrate combustion and steam reforming for waste to gas technologies. The project continues to investigate thermochemical conversion of logistical space mission trash to a gas for venting or reuse. This paper discusses the project advancements since the 2 second Drop Tower testing in 2018 and provides updated results from the 5 second Zero Gravity Facility experimentation in 2019. Trash injection, inlet reaction gas flow direction, heat transfer, ignition, combustion and mixed waste streams in a microgravity environment are investigated. Benchtop tests were performed to highlight the behavioral discrepancies of OSCAR within gravity and microgravity environments, which was the primary purpose of this work. Overall results are used to decide the appropriate method to model the system, help guide the design of how air, or other oxidant, should be introduced into the hearth zone for optimum material conversion, and assist in the next design phase for a suborbital flight demonstration. The work in this report presents the 5 second microgravity test campaign data with gravity data for space mission trash items, reactor design iterations, preheat temperature and trash ignition conditions.Item Suborbital Testing of the OSCAR Trash-to-Gas System(51st International Conference on Environmental Systems, 7/10/2022) Pitts, Ray; Meier, Anne; Olson, Joel; Shah, Malay; Rinderknecht, David; Toro Medina, JaimeWith the sustained human exploration of nearby celestial bodies on the horizon, a renewed outlook on waste management must be realized. Current waste management strategies aboard the International Space Station become impractical as we venture further away from low Earth orbit and the resources that can be extracted from waste streams are substantial. One method of combatting this issue is by thermally degrading solid and liquid crew waste items into a chemically inert, ventable gas stream, a process known as Trash-to-Gas. The Orbital Syngas/Commodity Augmentation Reactor (OSCAR) is the state-of-the-art Trash-to-Gas system which has been designed to explore microgravity Trash-to-Gas concepts for improved mass/volume reduction and resource recovery from waste. OSCAR is a subscale testbed design that supports the NASA Logistics Reduction (LR) project under the Advanced Exploration System (AES) Program and Space Technology Mission Directorate (STMD) Flight Opportunities Program to determine the feasibility of Trash-to-Gas technology for use on future long duration space missions. OSCAR has flown on two suborbital flight demonstrations aboard Blue Origin�s New Shepard launch vehicle. This paper presents an overarching comparative analysis of these microgravity test campaigns with 1g laboratory experimentation. Percent gasification, product gas composition, soot and water production, reactor temperature and pressure, trash injection methodology, and system automation are compared to highlight the operational discrepancies within the microgravity environment for future optimization. The OSCAR system design progression and up-to-date lessons learned are also discussed for consideration into follow-on human spaceflight mission architectures.Item Visible-Light-Responsive Photocatalysis: Ag-Doped TiO2 Catalyst Development and Reactor Design Testing(46th International Conference on Environmental Systems, 2016-07-10) Coutts, Janelle; Hintze, Paul; Meier, Anne; Devor, Robert; Surma, Jan; Maloney, Phillip; Bauer, Brint; Shah, Malay; Mazyck, DavidIn recent years, the alteration of titanium dioxide to become visible-light-responsive (VLR) has been a major focus in the field of photocatalysis. Currently, bare titanium dioxide requires ultraviolet light for activation due to its band gap energy of 3.2 eV. Hg-vapor fluorescent light sources are used in photocatalytic oxidation (PCO) reactors to provide adequate levels of ultraviolet light for catalyst activation; these mercury-containing lamps, however, hinder the use of this PCO technology in a spaceflight environment due to concerns over crew Hg exposure. VLR-TiO2 would allow for use of ambient visible solar radiation or highly efficient visible wavelength LEDs, both of which would make PCO approaches more efficient, flexible, economical, and safe. Over the past three years, Kennedy Space Center has developed a VLR Ag-doped TiO2 catalyst with a band gap of 2.72 eV and promising photocatalytic activity. Catalyst immobilization techniques, including incorporation of the catalyst into a sorbent material, were examined. Extensive modeling of a reactor test bed mimicking air duct work with throughput similar to that seen on the International Space Station was completed to determine optimal reactor design. A bench-scale reactor with the novel catalyst and high-efficiency blue LEDs was challenged with several common volatile organic compounds (VOCs) found in ISS cabin air to evaluate the system’s ability to perform high-throughput trace contaminant removal. The ultimate goal for this testing was to determine if the unit would be useful pre-heat exchanger operations to lessen condensed VOCs in recovered water and lowering the burden of VOC removal for water purification systems.