Journal: Journal of CO2 Utilization

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Elsevier

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2212-9820
2212-9839

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2020 - 20257
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Publications 1 - 7 of 7
  • Combining brine or CO2 geothermal preheating with low-temperature waste heat: A higher-efficiency hybrid geothermal power system
    Item type: Journal Article
    Garapati, Nagasree; Adams, Benjamin; Fleming, Mark R.; et al. (2020)
    Journal of CO2 Utilization
    Hybrid geothermal power plants operate by using geothermal fluid to preheat the working fluid of a higher-temperature power cycle for electricity generation. This has been shown to yield higher electricity generation than the combination of a stand-alone geothermal power plant and the higher-temperature power cycle. Here, we test both a direct CO2 hybrid geothermal system and an indirect brine hybrid geothermal system. The direct CO2 hybrid geothermal system is a CO2 Plume Geothermal (CPG) system, which uses CO2 as the subsurface working fluid, but with auxiliary heat addition to the geologically produced CO2 at the surface. The indirect brine geothermal system uses the hot geologically produced brine to preheat the secondary working fluid (CO2) within a secondary power cycle. We find that the direct CPG-hybrid system and the indirect brine-hybrid system both can generate 20 % more electric power than the summed power of individual geothermal and auxiliary systems in some cases. Each hybrid system has an optimum turbine inlet temperature which maximizes the electric power generated, and is typically between 100 °C and 200 °C in the systems examined. The optimum turbine inlet temperature tends to occur where the geothermal heat contribution is between 50 % and 70 % of the total heat addition to the hybrid system. Lastly, the CO2 direct system has lower wellhead temperatures than indirect brine and therefore can utilize lower temperature resources.
  • Towards a European supply chain for CO2 capture, utilization, and storage by mineralization: Insights from cost-optimal design
    Item type: Journal Article
    Ostovari, Hesam; Kuhrmann, Luis; Mayer, Fabian; et al. (2023)
    Journal of CO2 Utilization
    Carbon dioxide (CO2) capture, utilization, and storage (CCUS) by mineralization has been shown to reduce greenhouse gas (GHG) emissions not only in stand-alone plants but also in large-scale climate-optimal supply chains. Yet, implementing the large-scale supply chain for CCUS by mineralization requires a substantial financial investment and, thus, a deep understanding of its economics. The current literature estimates the economics of CO2 mineralization for stand-alone plants. While CO2 mineralization plants have their specific a) CO2 supply, b) solid feedstock supply, c) energy supply, and d) product market, the plant-level cost estimation does not account for a large and potentially shared supply chain. In our study, we assess the economics of mineralization by designing and analyzing cost-optimal supply chains for CCUS by mineralization in Europe. Our results show that the CO2e abatement costs of individual mineralization plants in a supply chain range from 110 to 312 €/ton CO2e avoided. The proposed supply chains for CCUS by mineralization can avoid 60 Mt CO2e/year in Europe at CO2e abatement costs comparable to CO2 capture and geological storage. Furthermore, we identify five locations that could offer a robust business case for CO2 mineralization. The analysis thus shows pathways on how to add CO2 mineralization to the GHG mitigation portfolio of Europe.
  • A 3D-printed metal-supported gyroid Ni/Al$_2$O$_3$ catalyst for CO$_2$ methanation
    Item type: Journal Article
    Jivrakh, Kedar Bharat; Alkhoori, Ayesha Abdulla Mohamed Abdulra; Palomino, Miguel; et al. (2025)
    Journal of CO2 Utilization
    The utilization of 3D-printing in catalyst production for CO$_2$ methanation has emerged as a response to the challenges posed by the highly exothermic reaction and high gas space velocity, conditions that necessitate enhanced heat and mass transfer while maintaining optimal catalytic performance. In this work, we developed a new CO$_2$ methanation catalyst comprising a Ni/Al$_2$O$_3$ powder-coated 3D-printed aluminum alloy of gyroid configuration. The metallic alloy (AlMgSi) was 3D-printed (3DAL) using selective laser melting (SLM), and Ni/ Al$_2$O$_3$ powder was coated on it by washcoating. Microscopy and tomography techniques were employed to examine the morphological characteristics of the catalyst and to analyze internal topology, and hydrogen temperature-programmed reduction (H$_2$-TPR) and chemisorption provided insights into the reduction sites and active metal phase. The catalytic performance was assessed through CO$_2$ methanation experiments at various temperatures ranging from 250 °C to 500 °C, using a CO$_2$:H$_2$:He gas mixture (1:4:5). The 3D-printed Ni/Al$_2$O$_3$-3DAL catalyst exhibited high CH$_4$ selectivity (97.7 %) and CO$_2$ conversion (77.6 %) at 400 °C, which is attributed to the reduced tendency of sintering and the effective heat transfer owing to the metallic support. The 3D-printed gyroid metallic support provided a higher surface area-to-volume ratio enabling higher catalyst loading per unit volume, and improved reactants contact with the active catalyst phase yielding enhanced catalytic performance compared to powder. It also offers enhanced thermal energy management and heat dissipation, which are critical for highly exothermic reactions such as CO$_2$ methanation, as well as mechanical strength compared to conventional beads and pellets.
  • Optimizing network pathways of CO2 conversion processes
    Item type: Journal Article
    Saad, Dimitri M.; Bilbeisi, Rana A.; Alnouri, Sabla Y. (2021)
    Journal of CO2 Utilization
    Carbon capture and utilization (CCU) has gained great attraction as an alternative route of producing carbon-based chemicals, which also mitigates atmospheric CO2. This paper develops a numerical optimization model that utilizes experimental data pertaining to the CO2 hydrogenation reaction (catalyst type, conversion, selectivity, and space velocity) to guide engineers to pick the optimal industrial scale CCU process. Four carbon conversion pathways that produce value-added chemicals are assessed: conversion into methanol, methane, carbon monoxide, and dimethyl ether. This techno-economic analysis is founded on elaborate sizing methods and process design principles of heat exchangers, compressors, reactors, and separators. Based on the collected data reported in the literature, the state-of-the-art model incorporates and assesses feed and catalyst costing, plant sizing and costing, and revenues from the produced commodity chemicals at market price. A thorough optimization analysis is conducted to determine the optimal conversion pathway subject to corresponding constraints. The objective of this problem targets cost minimization with respect to various production constraints. The results of the model show that the optimal CCU path is associated with the CO2-to-MeOH/DME reactions, with the model almost strictly allocating the available CO2 mass at the different production rates to processes generating these products. This result is due to the processes’ high reaction selectivity, which has been at the forefront of research in CO2 hydrogenation, in addition to the relatively high market price of both these products. Such results reinforce the promise of George Olah's Methanol Economy. The optimization model thus presents a novel basis for a comprehensive and quantitative multi-variable CCU plant assessment, utilizing optimized carbon conversion reaction data. © 2021 Elsevier
  • Mild-temperature gasification of biomass as a carbon-neutral CO2 utilisation process
    Item type: Journal Article
    Greencorn, Michael J.; Jackson, S. David; Hargreaves, Justin S.J.; et al. (2025)
    Journal of CO2 Utilization
    Applying CO2 as a gasifying agent for renewable biomass feedstocks represents an innovative method of carbon dioxide utilisation (CDU) that could be carbon neutral. This effect has now been observed under low gasification temperatures of 600 degrees C. When supplied at concentrations of 58.5 %v in a gasifying agent mixture with argon, CO2 was consumed in the resulting reaction and used to gasify char while producing excess syngas CO. This indicates a concentration-based push to drive CO2 utilisation reactions is possible at mild-temperatures, but net-CO2 conversion was limited to 0.434 % under these conditions. Conversion was highest during the period of char reduction following pyrolysis, indicating the principal route of conversion is the reverse Boudouard reaction. Mild-temperature CO2 gasification yielded an excess of 0.80 mmol/g of CO while generating 0.353 mmol/g less char-carbon than comparable pyrolysis experiments, further demonstrating the reverse Boudouard CO2-char conversion mechanism is active under these conditions. The CO2 gasifying agent does not appear to change the onset of pyrolytic devolatilization processes, although minor char-CO2 interactions are observed during pyrolysis as char is formed. Additionally, the CO2 atmosphere yielded 2.642 mmol/g more CH4 during devolatilization compared to pyrolysis under an inert atmosphere. These results are further discussed in the context of gasifier and system design parameters that maximise the thermal efficiency of integrated biomass power and BECCS (bioenergy with carbon capture and storage) cycles.
  • A CO2 valorization plant to produce light hydrocarbons: Kinetic model, process design and life cycle assessment
    Item type: Journal Article
    Cordero-Lanzac, Tomás; Ramirez Galilea, Adrian; Cruz-Fernandez, Marta; et al. (2023)
    Journal of CO2 Utilization
    Reliable Life Cycle Assessment (LCA) of processes for valorization of CO2-rich off-gas streams requires multidisciplinary contributions that span the development of active and selective catalysts, reactor design, plant modeling and optimization, as well as environmental impact analysis. Herein, we present the design and study of a CO2 valorization plant through methanol-mediated (tandem) hydrogenation to light hydrocarbons, with propane as the most abundant product. A state-of-the-art PdZn/ZrO2 + SAPO-34 catalyst combination was screened for catalytic activity and selectivity in a wide operation range. Optimal process conditions were found at 350 °C, 30–40 bar and co-feeding of CO2/CO. Kinetic parameters for the tandem reaction were extracted and used for the design of a multi-layer reactor, where the two catalysts are distributed according to: (i) CO2-to-methanol catalyst; (ii) mixed catalyst bed, and; (iii) methanol-to-hydrocarbons catalyst. This configuration outperformed the conventional dual bed and mixed bed reactor configurations in terms of process design. A Life Cycle Assessment of the plant suggested that a substantial decrease in the global warming impact of propane production will be highly driven by using green hydrogen from either solar or wind sources, although the comparison with fossil-derived propane indicated already a reasonable improvement even when using grey hydrogen from natural gas.
  • Enlightenment of ancient Tabia for sustainable construction material manufacture by accelerated CO₂ treatment
    Item type: Journal Article
    Du, Yao; Qi, Yuxuan; Zeng, Qiang; et al. (2024)
    Journal of CO2 Utilization
    Inspired by the wisdom of Tabia, an ancient building material with superior mechanical properties, this paper utilized accelerated CO₂ mineralization (CM) method to treat silty waste soil (SWS) with active lime after the pressing forming process for construction block manufacture. The influence of Ca(OH)₂ content and curing duration were explored. Results indicate that the generated CaCO₃ could fill pores and improve strength of the SWS blocks after CM treatment. At the optimal Ca(OH)₂ content of 15 % and curing duration of 24 h, the CM-SWS blocks possessed the compressive strength of 12.8 MPa, CO₂ emissions of 84.59 kgCO₂/m³ and cost of 196.26 CNY/m³, comparable with or superior than the commercial blocks. The findings would deepen the mechanistic understandings of CM treatment in material reinforcement, and pave a proof-of-concept path to sustainably upgrade the SWS of poor engineering performance for building material production.
Publications 1 - 7 of 7