SATPC0033026 Tab 04 4 SOW..pdf

The NASA NextSTEP-2 ISRU program (Contract 80HQTR19C0006) resulted in development of an integrated mission-scale Solid Oxide Electrolysis (SOXE) stack coupled with a methanation reactor system capable of producing high purity O2 and CH4 from H2O and CO2. The SOXE stack operating voltage is limited when CO2 is present to avoid the formation of solid carbon by electrolysis of produced CO when compared to SOXE operation with steam alone. The SOXE operation penalty for operating with CO2 is nearly 50% compared to steam electrolysis alone. A NASA SBIR program funded the development of an improved cathode material with the goal of producing a redox tolerant material. Initial testing of the new cathode material has demonstrated some resistance to coke formation as well. This advanced electrode has the potential to enable operation at higher cell voltage without the risk of carbon deposition. An alternative to co-electrolysis within a single SOXE stack would be the thermal and process integration of a Reverse Water Gas Shift (RWGS) reactor with a SOXE stack run in steam electrolysis mode.

Steam would be fed to the stack, then mixed with CO2 and passed over a RWGS catalyst at SOXE operating temperature to produce synthesis gas.

A study is proposed to optimize the NextSTEP-2 ISRU system for: 1) overall feed conversion to product O2 and CH4,

2) comparing theoretical performance of SOXE co-electrolysis vs SOXE steam electrolysis paired with a RWGS reactor for synthesis gas production, and 3) evaluating thermal management in both the RWGS and methanation reactors for performance and scaling considerations.

These study objectives would be accomplished by the following tasks:

Task 1: Conversion Mapping of integrated SOXE/ methanation reactor system--generate a predicted conversion map using OxEon’s proprietary SOXE stack calculation tool and Chemstation’s process simulation software, for the demonstration as currently designed. The conversion map will evaluate the impact of SOXE stack feed composition (ratio of H2O to CO2) and stack operating voltage on total O2 and CH4 production. Stack voltages will be evaluated for both nominal co-electrolysis operation as well as steam electrolysis operation while considering risk of carbon formation with heritage and advanced SOXE cathodes.

Task 2: Performance comparison between SOXE co-electrolysis vs integrated SOXE/ RWGS system—generate simulation models using OxEon’s proprietary SOXE stack calculation tool and Chemstation’s process simulation software, for SOXE co-electrolysis and an alternate SOXE/ RWGS for synthesis gas production. Performance comparisons will evaluate both the energy and mass required for each system for a target O2 and CH4 production rate.

Task 3: Thermal modeling of methanation reactor—coordinate with the Digital Engineering Design Center (DEDC) team at JSC to obtain the STAR-CCM+ model of the demonstration system methanation reactor. A graduate student will use the model/mesh to model the methanation reactor evaporative cooling jacket performance and scalability. Evaluation of heat generation in the catalyst bed and subsequent movement to the cooling jacket via OxEon’s novel thermal fin insert, will be done to identify scaling feasibility, both in reactor length and diameter.

The same model will be applied to the RWGS reactor to evaluate scalability and synthesis gas processing capabilities.