Supercritical Water Oxidation And A Preliminary Concept For Lunar Application

Author

Sheldon Cameron Scott, Prairie View A&M University

Date of Award

5-2025

Document Type

Thesis

Degree Name

Master of Science

Degree Discipline

Mechanical Engineering

Abstract

As the reach of space exploration extends further from Earth, the cost, time, and energy requirements necessary for life support of crewed expeditions exponentially increases. This makes the reclamation of resources paramount to the viability of such missions and will eventually become a major constraint for future destinations due to the expensive delivery of materials. Thusly, Supercritical Water Oxidation (SCWO) has been proposed to meet the requirements for the recovery of potable water needed for the drinking, hygiene, laundry, and irrigation performed by astronauts. This technique utilizes supercritical water’s properties above 374°C and 22.1 MPa alongside oxidants to convert organic hydrocarbons into products of pure water and carbon dioxide: generating higher yields of recovery without the waste by-products present within alternative waste treatment methods. The purpose of this research was to validate the effectiveness of SCWO for continuous operation, improve upon previous reactor designs with the addition of a mixing nozzle, perform a preliminary single-species analysis of waste constituents, and to develop a conceptual SCWO reactor for an early lunar base.

For this work, a tubular reactor designed at NASA Glenn Research Center was used to perform SCWO methodologies on waste streams that include ersatz wastewater (EWW)—a simulant representative of waste found on the International Space Station, urea, acetic acid, and ethanol diluted with deionized water to varying concentrations. Peak reaction temperatures ranged between 588˚C to 690˚C with operation pressures ranging from 26 MPa to 28 MPa. Samples from each experiment were analyzed through measurements of Total Organic Carbon (TOC), pH, turbidity, conductivity, and Raman spectroscopy. On average, the ersatz-based solutions displayed a >99% reduction in TOC. For the results of the urea-based solutions, the Raman characterizations showed greater development of intermittent species at lower throughputs suggesting an inverse trend with residence time and intermittent species generation. The opposite trend is present within the acetic acid Raman spectra that portray evidence of lesser intermittent species development at lower throughputs, or higher residence times. Finally, a lunar SCWO model was generated to perform a preliminary cost analysis for comparison with other water reclamation technologies proposed for ASA Artemis.

Index Terms: Raman spectroscopy, supercritical water, supercritical water oxidation (SCWO), Total Organic Carbon (TOC), water reclamation.

Committee Chair/Advisor

Ziaul Huque

Committee Member

Paul O. Biney

Committee Member

Jianren Zhou

Committee Member

Michael C. Hicks

Committee Member

Yuhao Xu

Publisher

Prairie View A&M University

Rights

Date of Digitization

5/13/2025

Contributing Institution

J. B . Coleman Library

City of Publication

Prairie View

MIME Type

Application/PDF

Recommended Citation

Scott, S. C. (2025). Supercritical Water Oxidation And A Preliminary Concept For Lunar Application. Retrieved from https://digitalcommons.pvamu.edu/pvamu-theses/1546