Performance Evaluation of Staged Bosch Process for CO2 Reduction to Produce Life Support Consumables

Abstract

Utilizing carbon dioxide to produce water and hence oxygen is critical for sustained manned missions in space, and to support both NASA's cabin Atmosphere Revitalization System (ARS) and In-Situ Resource Utilization (ISRU) concepts. For long term missions beyond low Earth orbit, where resupply is significantly more difficult and costly, open loop ARS, like Sabatier, consume inputs such as hydrogen. The Bosch process, on the other hand, has the potential to achieve complete loop closure and is hence a preferred choice. However, current single stage Bosch reactor designs suffer from a large recycle penalty due to slow reaction rates and the inherent limitation in approaching thermodynamic equilibrium. Developmental efforts are seeking to improve upon the efficiency (hence reducing the recycle penalty) of current single stage Bosch reactors which employ traditional steel wool catalysts. Precision Combustion, Inc. (PCI), with support from NASA, has investigated the potential for utilizing catalysts supported over short-contact time Microlith substrates for the Bosch reaction to achieve faster reaction rates, higher conversions, and a reduced recycle flows. Proof-of-concept testing was accomplished for a staged Bosch process by splitting the chemistry in two separate reactors, first being the reverse water-gas-shift (RWGS) and the second being the carbon formation reactor (CFR) via hydrogenation and/or Boudouard. This paper presents the results from this feasibility study at various operating conditions. Additionally, results from two 70 hour durability tests for the RWGS reactor are discussed. Nomenclature °C= degree Celsius cm = centimeter d = diameter ft = foot g-cat = gram of metal catalyst GSA = geometric surface area hr = hour in = inch kJ = kilojoules L = liter m = meter ml = milliliter

Perspective—Solid Oxide Cell Technology for Space Exploration

“…25 Furthermore, since the operating voltage for electrolysis is lower in solid oxide cells than that in the PEM cells due to improved electrode kinetics and higher operating temperature, the round-trip efficiency for unitized regenerative solid oxide cells is significantly higher. 26 Future Needs and Prospects Significant progress has recently been made for terrestrial applications regarding H 2 O electrolysis for hydrogen production, CO 2 electrolysis for CO production and co-electrolysis of H 2 O and CO 2 for syngas production, as well as solid oxide fuel cells for power generation. This terrestrial-focused effort has made substantial progress in improvements in the cathode, anode, and electrolyte materials and processes along with the overall SOFC/SOEC cell architecture.…”

The Potential for Electrons to Molecules Using Solar Energy

“…Packed bed membrane reactors have been investigated as the removal of produced water shifts the equilibrium to the right and removes the need for downstream water separation units (Samimi, Hamedi, and Rahimpour 2019;Dzuryk and Rezaei 2020). Also, NASA has investigated Precision Combustion Inc's RWGS reactor prototype based on patented Microlith technology to address issues such as reactor size and heat transfer associated with conventional RWGS reactors (Vilekar et al 2012;Abney et al 2016). There is also interest in reverse water gas-shift chemical looping, which is a high-temperature redox cycle comprised of the reduction of a metal oxide by hydrogen and the subsequent oxidation by CO2 to yield CO.…”

Estudio de optimización de los ciclos de calcinación carbonatación para la captura de CO2 en Centrales Térmicas de Carbón

“…Las altas eficiencias de los actuales tratamientos de desulfuración en las Centrales El ahorro de combustible previsto en la producción conjunta de CaO y H2 respecto de la producción separada de ambos en sus respectivos procesos de calcinación y reformado de vapor/CH4 en plantas modernas existente está en torno a un 70%. [52,55] Otra posibilidad de aprovechar las sinergias existentes en la calcinación es metanizar parte de los productos de la calcinación, CO o CO2 y el H2 generado en la oxidación parcial conjunta con el reformado de CH4 [58]. Tendrían lugar las reacciones Para ello se establecen los siguientes objetivos:…”