To close the loop in an Environmental Control and Life Support (ECLS) system that includes a Sabatier reactor to convert carbon dioxide to methane and water, a technology to recover hydrogen from the methane is required. Pyrolysis of methane to carbon and hydrogen has been demonstrated at a 4-crew scale, and can be part of a system with theoretical 100% recovery of oxygen. The hydrogen selectivity of the process is 99%. This paper provides an update on the development of a next generation flight-like advanced materials reactor that takes advantage of lightweight, non-metallic materials to convert 1.5 kg/day of methane to hydrogen and carbon with minimized power, densifying a substrate with solid, non-sooty carbon. To support design of the reactor and other system considerations, a reacting diffusion model has been developed using computational fluid dynamics (CFD) simulations of the complex hydrogen generation and carbon deposition reactions in both the gas phase and within the internal substrates. Results from this model are reported here, which predict methane conversion and how the substrate in the reactor will densify with carbon.
Parsons et al. (Sun,) studied this question.