In addition to carbon capture and storage, efforts are also being focussed on using captured CO2, both directly as a working fluid and in chemical conversion processes, as a key strategy for mitigating climate change and achieving resource efficiency. These processes require large amounts of energy, which should come from sustainable and, ideally, renewable sources. A strong value chain is required to support the production of valuable products from CO2. A value chain is a network of technologies and infrastructures (such as conversion, transportation, storage) along with its associated activities (such as sourcing raw materials, processing, logistics, inventory management, waste management) required to convert low-value resources to high-value products and energy services, and deliver them to customers. A CO2 value chain involves production of CO2 (involving capture and purification), technologies that convert CO2 and other materials into valuable products, sourcing of low-carbon energy to drive all of the transformation processes required to convert CO2 to products (including production of hydrogen, syngas, methane etc.), transport of energy and materials to where they are needed, managing inventory levels of resources, and delivering the products to customers, all in order to create value (economic, environmental, social etc.). Technologies underpinning future CO2 value chains were examined. CO2 conversion technologies, such as urea production, Sabatier synthesis, Fischer-Tropsch synthesis, hydrogenation to methanol, dry reforming, hydrogenation to formic acid and electrochemical reduction, were assessed and compared based on key performance indicators such as: CAPEX, OPEX, electricity consumption, TRL, product price, net CO2 consumption etc. Technologies for transport and storage of key resources are also discussed. This work lays the foundation for a comprehensive whole-system value chain analysis, modelling and optimisation.

Technologies and infrastructures underpinning future CO2 value chains: A comprehensive review and comparative analysis

Biomass-derived aviation fuels: Challenges and perspective

Efficient CO2 methanation over Ni/Al2O3 coated structured catalysts

Liquid fuel processing for hydrogen production: A review

Converting CO 2 -rich waste streams such as raw biogas, landfill gas and power plant flue gas into synthetic fuels and chemicals will reduce greenhouse gas emissions, providing revenue at the same time. One option is to convert CO 2 into CH 4 by hydrogenation via Sabatier reaction. This synthetic methane will be renewable if the H 2 required for the reaction is generated via water electrolysis using solar and wind energy or hydroelectricity. However, to realize the potential of this approach, a number of technological challenges related to the Sabatier reactor design have to be resolved, including thermal management. The high exothermicity of the Sabatier reaction can lead to reactor overheating. High temperatures are unfavorable to the exothermic and reversible methanation process, resulting in low CO 2 conversions. A simulation-based study of a Sabatier reactor was performed in order to optimize the removal of heat, while maximizing CO 2 conversion and CH 4 production. The heat-exchanger type packed bed reactor with internal cooling by a molten salt was simulated using a transient, pseudo-homogeneous mathematical model. Reactor performance was evaluated in terms of CO 2 conversion and CH 4 yield. The simulation results show that feed temperature, feed flow rate, and molten salt flow rate are the crucial parameters affecting the reactor performance. For the optimized operating conditions, the model predicts CO 2 conversions and CH 4 yields above 90% at high reactor throughputs, with space velocities up to 10,000 h −1 . A preliminary techno-economic evaluation is provided: opportunities and challenges are outlined.

Thermal management of a Sabatier reactor for CO2 conversion into CH4: Simulation-based analysis

The utilization of CO2 to produce life support consumables, such as O2 and H2O, via the Sabatier reaction is an important aspect of NASA s cabin Atmosphere Revitalization System and In-Situ Resource Utilization architectures for both low-earth orbit and long-term manned space missions. In the current International Space Station (ISS) and other low orbit missions, metabolically-generated CO2 is removed from the cabin air and vented into space, resulting in a net loss of O2. This requires a continuous resupply of O2 via water electrolysis, and thus highlights the need for large water storage capacity. For long-duration space missions, the amount of life support consumables is limited and resupply options are practically nonexistent, thus atmosphere resource management and recycle becomes crucial to significantly reduce necessary O2 and H2O storage. Additionally, the potential use of the Martian CO2-rich atmosphere and Lunar regolith to generate life support consumables and propellant fuels is of interest to NASA. Precision Combustion, Inc. (PCI) has developed a compact, lightweight Microlith(Registered TradeMark)-based Sabatier (CO2 methanation) reactor which demonstrates the capability of achieving high CO2 conversion and near 100% CH4 selectivity at space velocities of 30,000-60,000 hr-1. The combination of the Microlith(Registered TradeMark) substrates and durable, novel catalyst coating permitted efficient Sabatier reactor operation that favors high reactant conversion, high selectivity, and long-term durability. This paper presents the reactor development and performance results at various operating conditions. Additionally, results from 100-hr durability tests and mechanical vibration tests are discussed.

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Compact and Lightweight Sabatier Reactor for Carbon Dioxide Reduction

Development of integrated reformer systems for syngas production

An apparatus and process for thermally-linked adsorption-desorption. The process involves (a) at least one pair of adjacent sorbent beds, referenced herein as first and second sorbent beds, each pair of adjacent beds being thermally-linked one to the other through a thermally conductive wall; wherein each sorbent bed comprises a heat conductive foam, such as a reticulated metallic foam or sponge, having a sorbent coated thereon; then (b) alternating a flowstream between the beds such that at least one bed operates in adsorption cycle to remove target compound(s) from the flowstream with generation of heat of adsorption, which is conductively transferred away from the first bed towards the second bed, while operating the second bed in desorption cycle to remove the adsorbed target compound(s).

Adsorption-desorption apparatus and process

In NASA s Vision for Space Exploration, humans will once again travel beyond the confines of earth s gravity, this time to remain there for extended periods. These forays will place unprecedented demands on launch systems. They must not only blast out of earth s gravity well as during the Apollo moon missions, but also launch the supplies needed to sustain a larger crew over much longer periods. Thus all spacecraft systems, including those for the separation of metabolic carbon dioxide and water from a crewed vehicle, must be minimized with respect to mass, power, and volume. Emphasis is also placed on system robustness both to minimize replacement parts and ensure crew safety when a quick return to earth is not possible. This paper describes efforts to improve on typical packed beds of sorbent pellets by making use of structured sorbents and alternate bed configurations to improve system efficiency and reliability. The development efforts described offer a complimentary approach combining testing of subscale systems and multiphysics computer simulations to characterize the regenerative heating substrates and evaluation of engineered structured sorbent geometries. Mass transfer, heat transfer, and fluid dynamics are included in the transient simulations.

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Engineered Structured Sorbents for the Adsorption of Carbon Dioxide and Water Vapor from Manned Spacecraft Atmospheres: Applications and Testing 2008/2009

The utilization of CO2 to produce life support consumables, such as O2 and H2O, via the Sabatier reaction is an important aspect of NASA's cabin Atmosphere Revitalization System (ARS) and In-Situ Resource Utilization (ISRU) architectures for both low-earth orbit and long-term manned space missions. Carbon dioxide can be reacted with H2, obtained from the electrolysis of water, via Sabatier reaction to produce methane and H2O. Methane can be stored and utilized as propellant while H2O can be either stored or electrolyzed to produce oxygen and regain the hydrogen atoms. Depending on the application, O2 can be used to replenish the atmosphere in human-crewed missions or as an oxidant for robotic and return missions. Precision Combustion, Inc. (PCI), with support from NASA, has previously developed an efficient and compact Sabatier reactor based on its Microlith® catalytic technology and demonstrated the capability to achieve high CO2 conversion and CH4 selectivity (i.e., ≥90% of the thermodynamic equilibrium values) at high space velocities and low operating temperatures. This was made possible through the use of high-heat-transfer and high-surface-area Microlith catalytic substrates. Using this Sabatier reactor, PCI designed, developed, and demonstrated a stand-alone CO2 Reduction Assembly (CRA) test system for ground demonstration and performance validation. The Sabatier reactor was integrated with the necessary balance-of-plant components and controls system, allowing an automated, single "push-button" start-up and shutdown. Additionally, the versatility of the test system prototype was demonstrated by operating it under H2-rich (H2/CO2 of >4), stoichiometric (ratio of 4), and CO2-rich conditions (ratio of <4) without affecting its performance and meeting the equilibrium-predicted water recovery rates. In this paper, the development of the CRA test system for ground demonstration will be discussed. Additionally, the performance results from testing the system at various operating conditions and the results from durability testing will be presented.

/pdf/co2-reduction-assembly-prototype-using-microlith-based-5zn8uju0ah.pdf

Christian Junaedi

Papers

Compact and Lightweight Sabatier Reactor for Carbon Dioxide Reduction

Development of integrated reformer systems for syngas production

Adsorption-desorption apparatus and process

Engineered Structured Sorbents for the Adsorption of Carbon Dioxide and Water Vapor from Manned Spacecraft Atmospheres: Applications and Testing 2008/2009

CO2 Reduction Assembly Prototype Using Microlith-Based Sabatier Reactor for Ground Demonstration