Demonstration of Plasma Assisted Waste Conversion to Gas

The 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.