Solid Reactor Research Articles

Selective and Stable Ethanol Synthesis via Electrochemical CO2 Reduction in a Solid Electrolyte Reactor

Selective and Stable Ethanol Synthesis via Electrochemical CO₂ Reduction in a Solid Electrolyte Reactor

Electrochemically-Driven Solid Oxide Tubular Membrane Reactor for Efficient Separation of Oxygen and Argon

Electrochemically-Driven Solid Oxide Tubular Membrane Reactor for Efficient Separation of Oxygen and Argon

Investigation on thermal response of high temperature heat pipe under thermal mismatch conditions

As an efficient and reliable passive heat transfer equipment, high temperature heat pipes (HTHPs) plays an important role in HTHP solid state reactor system. HTHPs often encounter thermal mismatch in reactor applications, which will lead to capillary action, entrainment, and other characteristics, resulting in HTHP failure due to heat transfer limits. In this paper, the thermal response test of liquid metal HTHP under thermal mismatch conditions is studied, and the simulation test platform of HTHP mismatch is designed and built to measure the important physical parameters. The test results show that the heat transfer performance of the HTHP is the best under the condition of horizontal inclination of 60°, and the condenser power is 5.66 kW. This condition is selected as the reference condition for the transient condition test. When the HTHP experienced a transient power increase, the middle of the evaporator section, as the part with the largest heat flux of heating power, appeared a severe overheating phenomenon. The wall temperature of the evaporator section soared from 750 ℃ to 1050 ℃ in a short time, and the heating rate reached 18.9 ℃/min, which affected the smooth operation of the HTHP. When the HTHP encounters an inclination angle transient increase condition, the entrainment phenomenon is more severe, the temperature fluctuation of the condenser section is intensified, and the heat transfer of the HTHP is in an unstable state. When the HTHP encounters an inclination angle transient decrease condition, the temperature rise of the evaporator section is less than 10 ℃, the temperature at the end of the condenser section is increased, and the start-up performance of the HTHP is improved. In summary, this paper obtains the thermal response rule of HTHPs under thermal mismatch conditions through experimental research, which provides support for the safe application of HTHPs for special equipment.

Electrochemical regeneration of high-purity CO2 from (bi)carbonates in a porous solid electrolyte reactor for efficient carbon capture

Electrochemical regeneration of high-purity CO2 from (bi)carbonates in a porous solid electrolyte reactor for efficient carbon capture

Literature Review on Thermodynamic and Kinetic Limitations of Thermal Decomposition of Methane

The state of the art in methane pyrolysis does not yet provide a definitive answer as to whether the concept of an elementary reaction is universally applicable to the apparently simple process of methane dissociation. Similarly, the literature currently lacks a comprehensive and unambiguous description of the methane pyrolysis process and, in particular, a single model that would well represent its course at both the micro and macro scales. Given the wide range of conditions under which this reaction can occur—whether thermal or thermo-catalytic, in solid or fluidized bed reactors—it is crucial to evaluate the usefulness of different kinetic models and their compatibility with basic thermodynamic principles and design assumptions. To address these research gaps, the authors analysed the thermodynamic and kinetic dependencies involved in the thermal decomposition of methane, using the synthesis of methane from its elemental components and its reversibility as a basis for exploring suitable kinetic models. Using experimental data available in the literature, a wide range of kinetic models have been analysed to determine how they all relate to the reaction rate constant. It was found that regardless of whether the process is catalytic or purely thermal, for temperatures above 900 °C the reversibility of the reaction has a negligible effect on the hydrogen yield. This work shows how the determined kinetic parameters are consistent with the Kinetic Compensation Effect (KCE) and, by incorporating elements of Transition State Theory (TST), the possibility of the existence of Entropy–Enthalpy Compensation (EEC). The indicated correspondence between KCE and EEC is strengthened by the calculated average activation entropy at isokinetic temperature (∆SB=−275.0 J·(mol·K)−1). Based on these results, the authors also show that changes in the activation energy (E=20–421 kJ·mol−1) can only serve as an estimate of the optimal process conditions, since the isoconversion temperature (Tiso=1200−1450 K>Teq) is shown to depend not only on thermodynamic principles but also on the way the reaction is carried out, with temperature (T) and pressure (P) locally compensating each other.

Solid electrolyte reactor for nitrate-to-ammonia

Solid electrolyte reactor for nitrate-to-ammonia

CatchyCFDEM: Open-source microkinetic modeling of heterogeneous catalysis in Eulerian-Lagrangian CFD applied to oxidative coupling of methane

This work introduces catchyCFDEM, an OpenFOAM-based open-source CFD-DEM framework designed for simulating reactive gas–solid fluidized beds with both gas-phase chemistry and heterogeneous catalytic chemistry. A convective gas–solid heat transfer model is implemented and validated using experimental data gathered in a non-reactive pseudo-2D fluidized bed. Catalytic chemistry including different levels of complexity are included: pseudo-homogeneous, heterogeneous without mass transfer, and heterogeneous with diffusive mass transfer. Verification studies are performed by simulating a packed bed reactor using catchyCFDEM and comparing mass fraction profiles to a 1D plug flow simulation in Cantera. To enhance the computational efficiency of the resource-intensive reactive CFD-DEM simulations, speed-up algorithms such as Particle Agglomeration (PA) and in-situ adaptive tabulation (ISAT) are integrated in catchyCFDEM. As a case study, a gas–solid vortex reactor (GSVR) is simulated using the validated framework. The applicability of the GSVR for the oxidative coupling of methane (OCM) is evaluated based on an isothermal analysis evaluating the influence of several operational and geometrical parameters on the process. Finally, a proof-of-concept adiabatic simulation of the GSVR is presented. The catchyCFDEM framework is made publicly available on GitHub.

Fabricated ZnIn2S4/Cu2S S-scheme heterojunction with snowflake structure for boosting photocatalytic CO2 reduction in gas–solid reactor

Designing S-scheme heterojunctions has become a powerful strategy to enhance photocatalytic activity and improve the localization of catalyst surface charge. Therefore, more and more research has been devoted to S-scheme heterojunctions. In this work, we employed a simple two-step hydrothermal method to fabricate S-scheme ZnIn2S4/Cu2S (ZIS/Cu2S) heterojunctions. The results show that the composites exhibit good performance in the photoreduction of CO2 to CO and CH4. Especially, at 40 %-ZIS/Cu2S, the release rates of CO and CH4 were 13.35 μmol g−1 and 34.81 μmol g−1 under the condition of a 4 h reaction, and the selectivity of CH4 reached 80 %. In addition, the in situ FTIR test revealed that the catalyst promoted the formation of the key intermediates COOH* and CH3O* under the effect of light interaction, which was favorable to the photoreduction of CO2. This indicates that the electron transfer path of S-type not only promotes the separation of carriers for conversion but also has a strong redox ability to selectively convert CO2 to CH4, which provides some thoughts for the design of S-scheme heterojunction photocatalysts. This provides some thoughts for the design of S-scheme heterojunction photocatalysts.

Electrochemical nitrate reduction to ammonia with cation shuttling in a solid electrolyte reactor

Electrochemical nitrate reduction to ammonia with cation shuttling in a solid electrolyte reactor

Continuous Direct Air Capture and Electrochemical Conversion of CO2 and H2O into Ethylene and Oxygen in Solid Electrolyte Reactor

Chemelectronics LLC has developed economical approach to use solar energy to convert CO2 directly captured from air using carbon dioxide capture conductive sorbent materials coated on carbon foam electrodes into chemical products (ethylene) and oxygen from nick foam electrodes separated with solid polyelectrolytes. We take advantage of commercial off-the-shelf solar panels as electricity to supply the electrochemical reduction of CO2 directly captured from air into chemical products with zero carbon emission.Based on the life cycle analysis, there is no CO2 emission from CO2 capture and conversion. The energy will be produced from solar panels.

Cobalt-Doped Bismuth Nanosheet Catalyst for Enhanced Electrochemical CO2 Reduction to Electrolyte-Free Formic Acid.

Electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) to valuable liquid fuels, such as formic acid/formate (HCOOH/HCOO-) is a promising strategy for carbon neutrality. Enhancing CO2RR activity while retaining high selectivity is critical for commercialization. To address this, we developed metal-doped bismuth (Bi) nanosheets via a facile hydrolysis method. These doped nanosheets efficiently generated high-purity HCOOH using a porous solid electrolyte (PSE) layer. Among the evaluated metal-doped Bi catalysts, Co-doped Bi demonstrated improved CO2RR performance compared to pristine Bi, achieving ~90 % HCOO- selectivity and boosted activity with a low overpotential of ~1.0 V at a current density of 200 mA cm-2. In a solid electrolyte reactor, Co-doped Bi maintained HCOOH Faradaic efficiency of ~72 % after a 100-hour operation under a current density of 100 mA cm-2, generating 0.1 M HCOOH at 3.2 V. Density functional theory (DFT) results revealed that Co-doped Bi required a lower applied potential for HCOOH generation from CO2, due to stronger binding energy to the key intermediates OCHO* compared to pure Bi. This study shows that metal doping in Bi nanosheets modifies the chemical composition, element distribution, and morphology, improving CO2RR catalytic activity performance by tuning surface adsorption affinity and reactivity.

Solid Oxide Cell Reactor Model for Transient and Stationary Electrochemical H2O and CO2 Conversion Process Studies

The ability of high-temperature solid oxide cell (SOC) electrochemical reactors to efficiently convert atmospheric carbon to high value chemicals for industrial and energy storage applications via CO2 and co-electrolysis makes them a key technology for active carbon utilisation. However, due to additional operational risks from thermochemical reactions on thermal management, limited experimental capacity, and relative novelty, CO2 and co-electrolysis lag behind steam electrolysis in large-scale adoption. Here, a 1D+1D SOC model based on fundamental first principles considering three-dimensional heat transfer was improved via a unique method for representing co-electrolysis electrochemistry, solving with low computational effort. Validation against experimental data for two compositions and pressures, showed high levels of accuracy with respect to characteristic cell voltages, temperatures, and outlet compositions. The model also showed CO2 reduction during co-electrolysis mainly occurred via reverse water gas shift, while CO2 electrolysis still accounted for up to 35% of the total share. Pressurised co-electrolysis operation promotes exothermic methanation, causing pronounced heating of the reactor, consequently reducing the isothermal current density. Therefore, low to moderate pressurisation is likely most suited for coupling with downstream synthesis processes to avoid the installation of unnecessarily large systems and associated high costs.

Efficient industrial-current-density H2O2 production in neutral medium via external-shell boron regulation on single-atom VN4 sites

The unamiable electrolyte environment and insufficient kinetics of electrochemical two-electron oxygen reduction reaction (2e− ORR) hinders its application in producing H2O2. To address this issue, nitrogen-coordinated single atom vanadium with external shell boron regulation is designed for efficient H2O2 production in neutral medium. The optimal catalyst VN4B/NC showcase a 2e− ORR pathway selectivity of 96.6 % in 0.1 M Na2SO4. And the high current density (1.1 A cm−2) and excellent production rate (16.23 mmol cm−1 h−1) in flow cell further confirm its superior activity. Moreover, VN4B/NC exhibits potential application in solid electrolyte reactor, which is demonstrated by the production rate of 10.18 mmol cm−1 h−1 and long-term stability up to 100 h. Mechanism study suggest the external shell B regulation optimize the adsorption of OOH* intermediates on V sites, boosting the 2e− ORR pathway. This work provides novel insights to rational design of electrocatalysts for commodity chemicals production.

Microstructured gas-liquid-(solid) interfaces: A platform for sustainable synthesis of commodity chemicals.

Gas-liquid-solid catalytic reactions are widespread in nature and man-made technologies. Recently, the exceptional reactivity observed on (electro)sprayed microdroplets, in comparison to bulk gas-liquid systems, has attracted the attention of researchers. In this perspective, we compile possible strategies to engineer catalytically active gas-liquid-(solid) interfaces based on membrane contactors, microdroplets, micromarbles, microbubbles, and microfoams to produce commodity chemicals such as hydrogen peroxide, ammonia, and formic acid. In particular, particle-stabilized microfoams, with superior upscaling capacity, emerge as a promising and versatile platform to conceive high-performing (catalytic) gas-liquid-(solid) nanoreactors. Gas-liquid-(solid) nanoreactors could circumvent current limitations of state-of-the-art multiphase reactors (e.g., stirred tanks, trickle beds, and bubble columns) suffering from poor gas solubility and mass transfer resistances and access gas-liquid-(solid) reactors with lower cost and carbon footprint.

Continuous Direct Air Capture and Electrochemical Conversion of CO2 and H2O into Ethylene and Oxygen in a Solid Electrolyte Reactor

Continuous Direct Air Capture and Electrochemical Conversion of CO₂ and H₂O into Ethylene and Oxygen in a Solid Electrolyte Reactor

Bioinspired Binding and Conversion of Linear Monoterpenes by Polyaromatic Coordination Capsules.

Linear monoterpenes, versatile reaction biosubstrates, are bound and subsequently converted to various cyclic monomers and oligomers with excellent selectivity and efficiency, only in natural enzymes. We herein report bioinspired functions of synthetic polyaromatic cavities toward linear monoterpenes in the solution and solid states. The cavities are provided by polyaromatic coordination capsules, formed by the assembly of Pt(II) ions and bent bispyridine ligands with two anthracene panels. By using the capsule cavities, the selective binding of citronellal from mixtures with other monoterpenes and its preferential vapor binding over its derivatives are demonstrated in water and in the solid state, respectively. The capsule furthermore extracts p-menthane-3,8-diol, with high product- and stereoselectivity, from a reaction mixture obtained by the acid-catalyzed cyclization of citronellal in water. Thanks to the inner and outer polyaromatic cavities, the catalytic cyclization-dimerization of vaporized citronellal efficiently proceeds in the acid-loaded capsule solid and product/stereoselectively affords p-menthane-3,8-diol citronellal acetal (∼330% yield based on the capsule) under ambient conditions. The solid capsule reactor can be reused at least 5 times with enhanced conversion. The present study opens up a new approach toward mimicking terpene biosynthesis via synthetic polyaromatic cavities.

Integrated Heat Recovery System Based on Mixed Ionic-Electronic Conducting Membrane for Improved Solid Oxide Co-Electrolyzer Performance.

The current state of mixed ionic-electronic conducting ceramic membrane technology presents significant advancements with potential applications in various fields including solid oxide electrolyzers, fuel cells, hydrogen production, CO2 reduction, and membrane reactors for chemical production and oxygen separation. Particularly in oxygen separation applications, optimal conditions closely align with the conditions of oxygen-rich air streams emitted from the anode of solid oxide co-electrolyzers. This paper describes and analyzes a novel integrated heat recovery system based on mixed ionic-electronic conducting membranes. The system operates in two stages: firstly, oxygen is separated from the anode output stream using mixed ionic-electronic conducting membranes aided by a vacuum system, followed by the heat recovery process. Upon oxygen separation, the swept gas stream is recirculated at temperatures near thermoneutral conditions, resulting in performance improvements at both cell and system levels. Additionally, an oxygen stream is generated for various applications. An Aspen HYSYS® model has been developed to calculate heat and material balances, demonstrating the efficiency enhancements of the proposed system configuration.

Structural Effects of 3D Inkjet-Printed Ni(O)-YSZ Pillared Electrodes on Performances of Solid Oxide Electrochemical Reactors.

Increasing densities of reaction sites for gaseous reactants in solid oxide electrochemical reactors (SOERs), is a key strategy for achieving enhanced performance in either fuel cell or electrolysis modes. Fabrication of 3D structured components in SOERs can enhance those densities of reaction sites, which is achieved by 3D inkjet printing with high reproducibility, having developed inks with appropriate properties. First, the effects of pillar geometries on SOER performances are predicted through numerical simulations, enabling subsequent 3D printing to focus on the more effective geometries. Herein, the study reports the results of experimental validation of those predictions by evaluating the electrochemical performances of cells with various heights of 3D inkjet-printed Ni(O)- yttria stabilized zirconia (YSZ) pillars and YSZ pillars. Those measurements prove that increasing pillar heights generally increases SOER peak power densities in fuel cell mode and increased current densities at the thermoneutral potential (1.285V) in steam electrolysis mode, as predicted by simulations. With increasing pillar heights, more limitations in performance enhancement are found with YSZ electrolyte pillars than with Ni-YSZ pillars, again as predicted by simulations. The subsequent microstructural analysis of Ni-YSZ pillars proves the suitability of the Ni(O)-YSZ composite particle ink formulation and the reliability of 3D printing.

Machine learning modelling and optimization for metal hydride hydrogen storage systems

Use of machine learning models for solid state hydrogen storage reactor development.

Strongly Coupled Ag/Sn–SnO2 Nanosheets Toward CO2 Electroreduction to Pure HCOOH Solutions at Ampere-Level Current

HighlightsThe strongly coupled Ag/Sn–SnO2 nanosheets (NSs) were prepared via a versatile electrochemical template strategy, and the generated electron-enriched Sn sites promote the formation of *OCHO and alleviate the energy barriers of *OCHO to *HCOOH.Ag/Sn–SnO2 NSs afford a superior activity toward CO2 electroreduction with current densities up to 2000 mA cm‒2 and near-unity selectivity for formate production.Ag/Sn–SnO2 NSs as the cathode in a membrane electrode assembly with porous solid electrolyte reactor enable the direct production of ~ 0.12 M pure HCOOH solution for 200 h.