Hydrogen Dioxide Research Articles

Continuous Biological Ex Situ Methanation of CO2 and H2 in a Novel Inverse Membrane Reactor (IMR)

A promising approach for carbon dioxide (CO2) valorization and storing excess electricity is the biological methanation of hydrogen and carbon dioxide to methane. The primary challenge here is to supply sufficient quantities of dissolved hydrogen. The newly developed Inverse Membrane Reactor (IMR) allows for the spatial separation of the required reactant gases, hydrogen (H2) and carbon dioxide (CO2), and the degassing area for methane (CH4) output through commercially available ultrafiltration membranes, enabling a reactor design as a closed circuit for continuous methane production. In addition, the Inverse Membrane Reactor (IMR) facilitates the utilization of hydraulic pressure to enhance hydrogen (H2) input. One of the process’s advantages is the potential to utilize both carbon dioxide (CO2) from conventional biogas and CO2-rich industrial waste gas streams. An outstanding result from investigating the IMR revealed that, employing the membrane gassing concept, methane concentrations of over 90 vol.% could be consistently achieved through flexible gas input over a one-year test series. Following startup, only three supplemental nutrient additions were required in addition to hydrogen (H2) and carbon dioxide (CO2), which served as energy and carbon sources, respectively. The maximum achieved methane formation rate specific to membrane area was 87.7 LN of methane per m2 of membrane area per day at a product gas composition of 94 vol.% methane, 2 vol.% H2, and 4 vol.% CO2.

Comparative Hydrogen Production Routes via Steam Methane Reforming and Chemical Looping Reforming of Natural Gas as Feedstock

Hydrogen production is essential in the transition to sustainable energy. This study examines two hydrogen production routes, steam methane reforming (SMR) and chemical looping reforming (CLR), both using raw natural gas as feedstock. SMR, the most commonly used industrial process, involves reacting methane with steam to produce hydrogen, carbon monoxide, and carbon dioxide. In contrast, CLR uses a metal oxide as an oxygen carrier to facilitate hydrogen production without generating additional carbon dioxide. Simulations conducted using Aspen HYSYS analyzed each method’s performance and energy consumption. The results show that SMR achieved 99.98% hydrogen purity, whereas CLR produced 99.97% purity. An energy analysis revealed that CLR requires 31% less energy than SMR, likely due to the absence of low- and high-temperature water–gas shift units. Overall, the findings suggest that CLR offers substantial advantages over SMR, including lower energy consumption and the production of cleaner hydrogen, free from carbon dioxide generated during the water–gas shift process.

Kinetic Characterization of Pt/Al2O3 Catalyst for Hydrogen Production via Methanol Aqueous-Phase Reforming

Compared to steam reforming, methanol aqueous-phase reforming (APR) converts methanol to hydrogen and carbon dioxide at lower temperatures, but also displays lower conversion rates. Herein, methanol APR is studied over the active Pt/Al2O3 catalyst under different operating conditions. Studies were conducted at different temperatures, pressures, methanol mass fractions, and residence times. APR performance was evaluated in terms of methanol conversion, hydrogen production rate, hydrogen selectivity, and by-product formation. The results revealed that an increase in operating pressure and methanol mass fraction had an adverse effect on the APR performance. Conversely, it was found that hydrogen selectivity was unaffected by the operating pressure and residence time for the methanol feed mass fraction of 5%. For the methanol feed mass fraction of 55%, hydrogen selectivity was improved by operating pressure and residence time. The alumina support phase change to boehmite as well as sintering and leaching of the catalytic particles were observed during catalyst stability experiments. Additionally, a comparison between methanol steam reforming (MSR) and APR was also performed.

A bio‐reactive transport model for biomethanation in hydrogen underground storage sites

AbstractUnderground biomethanation, which relies on the subsurface microbial activity to convert hydrogen and carbon dioxide into methane, is a promising approach to support carbon capture, utilization, and storage technology. The process involves injecting hydrogen with captured CO2 into depleted oil and gas reservoirs or aquifers colonized by hydrogenotrophic methanogens that can convert these two substrates into methane. Despite the attractiveness of this technology, there are still uncertainties about the efficiency of the conversion process, particularly the impact of microbial parameters. To investigate the efficiency of the hydrogen conversion process, we relied on a bio‐reactive transport model that can mimic microbial growth and decay, consumption of substrates, and transport of reactants and products. It was found that the methane concentration peaks near the injection well when the hydrogen fraction is in the range of 75% to 80% of the injected gas composition. In addition, a noticeable hydrogen sulfide concentration can be produced due to sulfide ions in the brine. Using the Kozeny‐Carman relation, an attempt was made to correlate microbial growth with reduced porosity and permeability. It was then revealed that substrate consumption by microbes leads to a drastic increase in the microbial population in the subsurface, which can reduce the petrophysical properties of the reservoir, especially in the near wellbore area. The results obtained from a series of parametric analyses showed that the hydrogen concentration in the injected gas, pressure, well spacing, and injection rate are some of the most important parameters contributing to the biomethanation process. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Optimizing process parameters and materials for the conversion of plastic waste into hydrogen

Abstract This study has investigated hydrogen production from waste plastics using pyrolysis, steam methane reforming, and water-gas-shift reactions modelled via Aspen Plus. After evaluating multiple alternatives, polypropylene (PP) was selected as the feedstock. The research has been focused on how reformer temperature, steam-to-fuel ratio (S/F), reformer pressure, and pyrolysis temperature impact syngas composition, heating values, syngas (H2/CO) ratios, and yields of hydrogen (H2), methane (CH4), and carbon dioxide (CO2). Key findings have indicated that raising reformer temperatures to around 1000°C maximizes hydrogen production in syngas, reaching peak levels of 2360 Nm3/Ton and 2525 Nm3/Ton for reformer temperature and steam-to-fuel ratio (S/F) ratios, respectively, via processes like steam methane reforming and the water-gas-shift reaction. Moreover, other parameters like steam-to-fuel (S/F) ratio and reformer pressure have produced the highest amount of hydrogen at 0.25 and 1 atm, respectively. Optimizing reformer temperature and steam-to-fuel ratio (S/F) have been selected as key in hydrogen production, with peak lower heating values (LHV) of 1.15 MJ/kg for temperature and 1.035 MJ/kg for S/F ratios, highlighting the importance of balancing these parameters for efficiency. Additionally, syngas' hydrogen (H2) composition increased with pyrolysis temperature, peaking at 8.5% at 700°C. Finally, this research has provided valuable insights into optimizing process parameters for sustainable hydrogen production. Moreover, the simulation process has provided cost-effective adjustments and informed decision-making for sustainable and scalable technologies, benefiting researchers, investors, engineers, and policymakers involved in innovative hydrogen generation.

Methanothermobacter thermautotrophicus and Alternative Methanogens: Archaea-Based Production.

Methanogenic archaea convert bacterial fermentation intermediates from the decomposition of organic material into methane. This process has relevance in the global carbon cycle and finds application in anthropogenic processes, such as wastewater treatment and anaerobic digestion. Furthermore, methanogenic archaea that utilize hydrogen and carbon dioxide as substrates are being employed as biocatalysts for the biomethanation step of power-to-gas technology. This technology converts hydrogen from water electrolysis and carbon dioxide into renewable natural gas (i.e., methane). The application of methanogenic archaea in bioproduction beyond methane has been demonstrated in only a few instances and is limited to mesophilic species for which genetic engineering tools are available. In this chapter, we discuss recent developments for those existing genetically tractable systems and the inclusion of novel genetic tools for thermophilic methanogenic species. We then give an overview of recombinant bioproduction with mesophilic methanogenic archaea and thermophilic non-methanogenic microbes. This is the basis for discussing putative products with thermophilic methanogenic archaea, specifically the species Methanothermobacter thermautotrophicus. We give estimates of potential conversion efficiencies for those putative products based on a genome-scale metabolic model for M. thermautotrophicus.

Fidelibacter multiformis gen. nov., sp. nov., isolated from a deep subsurface aquifer and proposal of Fidelibacterota phyl. nov., formerly called Marine Group A, SAR406 or Candidatus Marinimicrobia.

A Gram-negative, obligatory anaerobic, chemoheterotrophic bacterium, designated strain IA91T, was isolated from sediments and formation water from deep aquifers in Japan. IA91T derives its peptidoglycan, energy and carbon from exogenous cell wall fragments, namely muropeptides, released from actively reproducing bacteria, and is dependent on other bacteria for cell wall formation, growth and even cell shape: IA91T is irregular rod-shaped but coccoids when muropeptide is absent. IA91T grew in a temperature range of 25-45 °C with optimum growth at 40 °C. IA91T utilized limited substrates, yeast extract, muropeptides and d-lactate. The major end products from yeast extract degradation were acetate, hydrogen and carbon dioxide. Co-cultivation with a hydrogen-scavenging methanogenic archaeon promoted IA91T growth. No anaerobic respiration with nitrate, nitrite, sulphate or Fe(III) was observed. The major cellular fatty acids are C16 : 0, C18 : 1 trans9, C18 : 0 and C17 : 0. The G+C content of the genomic DNA was 45.6 mol%. Phylogenetic analysis based on 16S rRNA gene and conserved protein sequences involved in replication, transcription and translation indicated that IA91T belonged to the candidate phylum Marine Group A (MG-A, SAR406 or Ca. Marinimicrobia) with no cultivated representatives. Based on the phenotypic and phylogenomic characteristics, a new genus and species, Fidelibacter multiformis gen. nov., sp. nov., is proposed for IA91T (= JCM 39387T = KCTC 25736T). In addition, a new bacterial phylum named Fidelibacterota phyl. nov. is proposed for the candidate phylum MG-A represented by F. multiformis and Fidelibacteraceae fam. nov., Fidelibacterales ord. nov. and Fidelibacteria classis nov.

Development and verification of a multi-component model for steam methane reforming

RELEVANCE. Steam methane reforming is the dominant method of hydrogen production. Its significant share in global CO2 emissions highlights the importance of optimizing technological parameters to reduce environmental impact. The developed multi-component model of steam methane reforming in COMSOL Multiphysics is relevant not only due to its applicability for optimizing existing production facilities but also for its potential in developing new methods for utilizing associated petroleum gas. In the context of import substitution in the hydrogen energy sector, this model is also of interest, allowing for the calculation of technological parameters of industrial installations.THE PURPOSE. The aim of the work is to develop and verify a multi-component model of steam methane reforming.METHODS. The research methodology includes the use of experimental data from the literature and industrial indicators for integration into a multi-component model in COMSOL Multiphysics. This enables the modelling of complex chemical interactions under conditions characteristic of the industrial steam methane reforming process.RESULTS. The developed multi-component model allows calculating key parameters of the steam methane reforming process, including the concentration of components (methane, hydrogen, carbon monoxide, and carbon dioxide) and temperature along the reactor. The model successfully describes the chemical interactions between components and takes into account the influence of operating conditions, such as temperature, pressure, and steam/gas ratio, on process efficiency. The model verification was carried out by comparing the modelling results with experimental data and indicators of real industrial processes. Their correspondence confirms the high degree of reliability and suitability of the model for practical application in engineering calculations and optimization of steam methane reforming processes.CONCLUSION. The conclusions made based on the modelling can be used for further improvement of methane conversion technologies, contributing to their efficiency and environmental friendliness. There is also potential for using the model to calculate the stages of installations for the utilization of products from the processing of associated petroleum gas.

Hydrogen Is the Superior Nebulization Gas for Desorption and Electrospray Ionization.

A previous comparative study between helium and nitrogen as nebulizing and desolvation gases in electrospray ionization (ESI) and desorption electrospray ionization (DESI) found that the signal responses of compounds of varying sizes and polarities were improved. Here, an expanded selection of nebulizing gases was evaluated to investigate mechanisms of improvement. The set of nebulizing gases included hydrogen, helium, nitrogen, argon, and carbon dioxide. Results indicate that the signal enhancements are achieved by gases lighter than nitrogen and that the previously described helium effects can be improved by using the more economical and sustainable hydrogen as a nebulizing gas. Additionally, H2 and He reduce the desorption footprint, which could be potentially useful in increasing the resolution of chemical imaging microscopy, especially since, despite the smaller footprint obtained using helium and hydrogen, higher signals are obtained compared to nitrogen.

An insight into hydrogen and carbon dioxide displacement and trapping efficiencies in carbonate formations through NMR and core flooding

The complex pore structure of carbonates can influence gas storage process to different extents, depending on stored gas type. Hence, investigating gas displacement and residual trapping in such formations is crucial. Here, several CO2 and H2 core flooding experiments were performed using three carbonate samples. The drainage process is followed by brine imbibition to test gas residual trapping. Additionally, nuclear magnetic resonance (NMR) T2 spectra measurements were conducted at different stages. The results show that H2 had less displacement efficiency in carbonates compared to CO2. The pore structure has a noticeable impact on CO2 displacement efficiency. However, H2 displacement efficiency is less sensitive to rock properties. The NMR-T2 measurements show that CO2 partially saturated medium-sized pores and almost filled all macropores during drainage. After imbibition, large pores are slightly re-saturated with brine with varying degrees compared to their initial brine saturations. H2 shows lower residual trapping efficiency compared to CO2.

Temperature-regulated gas adsorption on LTA zeolites: Observation of sorption isotherms for methane, hydrogen, nitrogen and carbon dioxide

Temperature-regulated gas adsorption of various zeolite LTAs with different cations of Cs2+, K+, Na+, and Ca2+ (namely, Cs-A, 3A, 4A, and 5A) was analysed in the presence of different gas molecules of H2, CO2, N2, and CH4 for pressures up to 800 kPa and temperatures ranging from 77.15 to 363.15 K. Over the range of test conditions, zeolite 5A (containing Ca2+ cations) exhibited the highest uptake at 800 kPa for CO2, H2, CH4, and N2, with capacity values of 5.69 mmol.g−1, 1.14 mmol.g−1, 6.60 mmol.g−1, and 6.10 mmol.g−1, at 298.15 K and 201.15 K respectively. Zeolite 4A (containing Na+ cations) exhibited 0.74 mmol.g−1 for H2 adsorption at 201.15 K, and 800 kPa. In contrast, pores were inaccessible to H2 on ion-exchange Cs-A zeolite at a temperature range of 77.15–343.15 K, due to larger cation Cs2+ (CsA) comparison with Na+ (4A). Interestingly, zeolite 3A (containing K+ cations) showed a negligible capacity for the larger gas molecules, CH4 and N2, ascribed to the pore space blocked by the larger K+ cations (relative to the smaller Na+ and Ca2+ cations). Zeolite 3A exhibited a temperature-dependent behaviour (i.e., presumably a “trapdoor” effect) with H2 wherein adsorption was negligible at 77.15 K, but was significant above approximately 200 K. For N2, zeolite 4A exhibits similar temperature-regulated adsorption characteristics (i.e., presumably a “trapdoor” mechanism as well). These zeolite materials used in various temperature swing processes could be particularly beneficial in natural hydrogen production (with H2/N2 separation with 3A), the production of synthetic fuels from CO2/H2 mixtures (with both 3A and 4A), CO2 capture from waste streams, and applications for H2/N2 separation.

Solubilities of Hydrogen, Nitrogen and Carbon Dioxide in the Eutectic Mixture of Diphenylmethane and Biphenyl

Solubilities of Hydrogen, Nitrogen and Carbon Dioxide in the Eutectic Mixture of Diphenylmethane and Biphenyl

Gas tightness around salt cavern gas storage in bedded salt formations

Underground salt cavern storage has become the preferred medium for storing gas energy and strategic substances. Salt caverns are suitable for storing small molecular gases due to the low porosity and permeability of salt rocks. This paper comprehensively analyzes the physical properties of four gases - hydrogen, helium, methane, and carbon dioxide - under subsurface temperature and pressure conditions. It categorizes the flow regimes of these gases in salt rocks under geological pressure conditions based on the Knudsen number. In a typical 1000 m salt cavern, the predominant permeation flow regime of four gases in the surrounding rock is Klinkenberg flow, with helium potentially undergoing transitional flow at low operation pressures. A 3D numerical model is established for an actual salt cavern to compare the permeation and leakage characteristics of these gases within salt rock formations. Results indicate that, under identical operation conditions, the permeation range of the gases decreases in the following order: hydrogen > methane > helium > carbon dioxide. Under the cyclic operation pressures, the cumulative leakage amount of hydrogen, helium, and methane increases over time, while that of carbon dioxide initially rises and then decreases. This behavior is attributed to the fact that the reverse-permeation rate of carbon dioxide at low pressures exceeds its permeation rate at high pressures. Over 30 years cyclic operation, the leakage ratios of the gases are as follows: hydrogen (13.29 %), methane (9.34 %), helium (7.47 %), and carbon dioxide (0.93 %), with hydrogen exhibiting the highest and carbon dioxide the lowest leakage ratios. Larger permeability results in a larger permeation range, while larger porosity leads to a smaller permeation range. When the permeability of salt layer is greater than 1e-20 m2, the permeation range of hydrogen significantly increases. Gas leakage ratios increase with permeability nonlinearly and increase with porosity linearly. The impact of salt layer permeability on leakage ratios is greater than that of porosity. This study provides crucial guidance for the selection of geological formations for storing hydrogen, helium, methane, and carbon dioxide in salt caverns, as well as the investigation of gas permeation characteristics in salt layers.

Isolation and characterization of novel acetogenic Moorella strains for employment as potential thermophilic biocatalysts.

Thermophilic acetogenic bacteria have attracted attention as promising candidates for biotechnological applications such as syngas fermentation, microbial electrosynthesis, and methanol conversion. Here, we aimed to isolate and characterize novel thermophilic acetogens from diverse environments. Enrichment of heterotrophic and autotrophic acetogens was monitored by 16S rRNA gene-based bacterial community analysis. Seven novel Moorella strains were isolated and characterized by genomic and physiological analyses. Two Moorella humiferrea isolates showed considerable differences during autotrophic growth. The M. humiferrea LNE isolate (DSM 117358) fermented carbon monoxide (CO) to acetate, while the M. humiferrea OCP isolate (DSM 117359) transformed CO to hydrogen and carbon dioxide (H2 + CO2), employing the water-gas shift reaction. Another carboxydotrophic hydrogenogenic Moorella strain was isolated from the covering soil of an active charcoal burning pile and proposed as the type strain (ACPsT) of the novel species Moorella carbonis (DSM 116161T and CCOS 2103T). The remaining four novel strains were affiliated with Moorella thermoacetica and showed, together with the type strain DSM 2955T, the production of small amounts of ethanol from H2 + CO2 in addition to acetate. The physiological analyses of the novel Moorella strains revealed isolate-specific differences that considerably increase the knowledge base on thermophilic acetogens for future applications.

Subsurface storage capacity in structural traps in underexplored sedimentary basins: Hydrogen (H 2 ) and carbon dioxide (CO 2 ) storage on the Irish Atlantic margin

Abstract Methodologies for storage assessment developed for basins with dense data coverage are typically not optimally applicable to underexplored sedimentary basins. To address this, a methodology and workflow for storage assessment in underexplored basins is presented which uses existing datasets to identify structural traps and populate a fluid-in-place equation which can be used for a variety of gases including CO 2 and H 2 . This is then applied to the Irish Atlantic margin; Jurassic, Triassic and Carboniferous reservoirs are investigated to understand their reservoir quality and extent, and related seals. Structural trap types are described and the theoretical capacities of three candidate sites with varying data coverage are calculated. The results highlight the potential for underexplored sedimentary basins on the Irish Atlantic margin to support offshore renewable energy projects and reduce Ireland's CO 2 emissions. This workflow is applicable to a variety of underexplored sedimentary basins and emphasises the utility of legacy hydrocarbon datasets for early-stage subsurface storage assessment. Other aspects of energy storage are also discussed, including man-made salt caverns, other candidate reservoir-seal pairs, and the potential for collaborative infrastructure development with CO 2 emitters and renewable energy projects.

Ppb-level H2 gas-sensor based on porous Ni-MOF derived NiO@CuO nanoflowers for superior sensing performance

Nickel oxide (NiO) is an optimal material for precise detection of hydrogen (H2) gas due to its high catalytic activity and low resistivity. However, the solid structure of NiO imposes limitations on the gas response kinetics of H2 gas molecules, resulting in a slower electron–hole transit and reduced gas response value. Herein, a unique NiO@CuO NFs with porous sharp-tip and nanospheres morphology was successfully synthesized by using a metal–organic framework (MOF) as a precursor. The fabricated porous 2 wt% NiO@CuO NFs describes outstanding selectivity towards H2 gas, including a high sensitivity of response value (170–20 ppm at 150 °C), is almost 28.3 % higher than that of porous Ni-MOF, low detection limit (300 ppb) with a notable response (21), short response and recovery times at (300 ppb, 40/63 s and 20 ppm, 100/167 s), exceptional long-term stability and repeatability. The study also explored the impact of relative humidity to evaluate the sensor performance under real-world conditions. The boosted hydrogen dioxide sensing properties may be attributed to synergistic effects of numerous factors including p-p heterojunction at the interface between NiO and CuO nanoflowers, especially a porous sharp-tip MOF structure and rough surface of nanospheres as well as the chemical sensitization effect of NiO. This research offers a viable method for creating unique MOS heterostructures from Ni-MOF and CuO that have unique morphologies and compositions that could be used for H2 gas sensing applications.

Recent advances in measuring the effects of diet on gastrointestinal physiology: Sniffing luminal gases and fecal volatile organic compounds.

Despite the huge pool of ideas on how diet can be manipulated to ameliorate or prevent illnesses, our understanding of how specific changes in diet influence the gastrointestinal tract is limited. This review aims to describe two innovative investigative techniques that are helping lift the veil of mystery about the workings of the gut. First, the gas-sensing capsule is a telemetric swallowable device that provides unique information on gastric physiology, small intestinal microbial activity, and fermentative patterns in the colon. Its ability to accurately measure regional and whole-gut transit times in ambulant humans has been confirmed. Luminal concentrations of hydrogen and carbon dioxide are measured by sampling through the gastrointestinal tract, and such application has enabled mapping of the relative amounts of fermentation of carbohydrates in proximal-versus-distal colon after manipulation of the types and amounts of dietary fiber. Second, changes in the smell of feces, via analysis of volatile organic compounds, occur in response to the diet, and by the presence and therapy of irritable bowel syndrome and inflammatory bowel disease. Such information is likely to aid our understanding of what dietary change can do to the colonic luminal microenvironment, and may value-add to diagnosis and therapeutic design. In conclusion, such methodologies enable a more complete physiological profile of the gastrointestinal tract to be created. Systematic description in various cohorts and effects of dietary interventions, particularly when co-ordinated with the analysis of microbiome, are needed.

Evaluating the impact of 3-nitroxypropanol supplementation on enteric methane emissions in pregnant non-lactating dairy cows offered grass silage

Although 3-nitroxypropanol (3-NOP; Bovaer10®) has been proven to reduce enteric methane (CH4) by ∼30% in indoor systems of dairying when the additive is mixed throughout a total mixed ration (TMR), there has been limited research to date on the CH4 abatement potential of 3-NOP when mixed within a perennial ryegrass silage only based diet and fed to pregnant nonlactating dairy cows. To investigate the effect of 3-NOP supplementation on enteric CH4 emissions of pregnant nonlactating dairy cows, an 6-week study was undertaken in which treatment cows were supplemented with 3-NOP mixed within grass silage, while control cows were offered grass silage without additive supplementation. Enteric CH4, hydrogen (H2) and carbon dioxide (CO2) were measured using a GreenFeed machine. Body weight (BW), body condition score (BCS), dry matter intake (DMI) and calf birthweight were monitored to determine the effect of 3-NOP supplementation on productivity. The measured dietary concentration of 3-NOP was 63 (range 53.2 - 77.1) mg / kg DM. There was no effect of 3-NOP supplementation on any of the production parameters. Cows supplemented with 3-NOP produced 22% less enteric CH4 per day and CH4 per kg DMI, respectively (P < 0.001) than cows offered the control diet. Cows supplemented with 3-NOP also produced 4.4 fold more H2 and H2 per kg DMI, respectively (P < 0.001) relative to the control. Supplementing pregnant nonlactating dairy cows with 3-NOP during the winter housing period effectively reduced enteric CH4 emissions without detriment to productivity.

Techno-Economics Analysis to Reshape Global Clean and Green Energy

Renewable methanol is produced from biomass or synthesized from green hydrogen and carbon dioxide CO2. These are essential components that are consumed as chemical feedstock and fuel. E-methanol is also vital in the petroleum/ petrochemical industry and transport sectors toward net carbon-neutral goals. In the current operational scenario, renewable methanol production costs are high, and production volumes are low. We need to establish the right policies to address the challenges of producing e-methanol costeffectively to deliver clean, green energy and fuel in the competitive market. Keywords—Green hydrogen, Electro Fuel, PV, Renewable, Emethanol

Investigation of the kinetics of methanation of a post-coelectrolysis mixture on a Ni/CZP oxide catalyst

The use of synthetic natural gas (SNG) as a plug-and-play fuel coming from renewables can help to overcome the limitations given by the intermittency of renewable energy. A way to implement the production of SNG pass through the co-electrolysis of CO2 to a mixture of hydrogen, carbon monoxide and carbon dioxide, steam and small amounts of methane, followed by CO and CO2 methanation. The presence of different reactants and processes requires the comprehension and quantification of the kinetics of the reactions involved with the aim of optimizing methanation. In this work a kinetic model that considers both the direct CO2 methanation and the indirect RWGS + CO methanation pathways has been developed over a Ni(10 %wt)/Ce0.33Zr0.63Pr0.04O2. The kinetic study made it possible to understand the influence of the reactants and products on the reactions through the calculation of reaction rates. This allowed to test, by linearization, the models found in the literature and their adjustment permitted to calculate sixteen kinetic parameters (activation energies, heats of adsorption and pre-exponential factors) present in the rate laws of methanation of CO2, CO and the Reverse Water Gas Shift reaction. The models then made it possible to simulate the evolution of partial flow rates in an isothermal plug flow reactor and were compared to experimental data.