Dry Methane Research Articles

Investigation of the evolution of Pd-Pt supported on ceria for dry and wet methane oxidation

Efficiently treating methane emissions in transportation remains a challenge. Here, we investigate palladium and platinum mono- and bimetallic ceria-supported catalysts synthesized by mechanical milling and by traditional impregnation for methane total oxidation under dry and wet conditions, reproducing those present in the exhaust of natural gas vehicles. By applying a toolkit of in situ synchrotron techniques (X-ray diffraction, X-ray absorption and ambient pressure photoelectron spectroscopies), together with transmission electron microscopy, we show that the synthesis method greatly influences the interaction and structure at the nanoscale. Our results reveal that the components of milled catalysts have a higher ability to transform metallic Pd into Pd oxide species strongly interacting with the support, and achieve a modulated PdO/Pd ratio than traditionally-synthesized catalysts. We demonstrate that the unique structures attained by milling are key for the catalytic activity and correlate with higher methane conversion and longer stability in the wet feed.

Performance improvement of the proton-conducting solid oxide electrolysis cell coupled with dry methane reforming

The proton-conducting solid oxide electrolysis cell (H-SOEC) is a clean technology for syngas production from H2O and CO2 through electrochemical and chemical reactions. However, it provides a low CO2 conversion and produces a syngas product with a high H2O content. To improve the H-SOEC for syngas production, H-SOEC coupled with a dry methane reforming process (H-SOEC/DMR) was proposed in this work. The process flowsheet of the H-SOEC/DMR was developed and further used to evaluate the performance of the H-SOEC/DMR process. From the performance analysis of the H-SOEC/DMR process, it was found that the CO2 and CH4 conversions were higher than 90% and 80%, respectively, when the process was operated in the temperature range of 1073–1273 K. In addition, the result showed that a syngas product with a low H2O content could be obtained. Energy efficiency was then considered and the results indicated that the highest energy efficiency of 72.80% could be achieved when the H-SOEC/DMR process was operated at a temperature of 1123 K, pressure of 1 atm, and current density of 2500 A m−2. Based on a pinch analysis, a heat exchanger network was applied to the H-SOEC/DMR process that improved the energy efficiency to 81.46%. Finally, an exergy analysis was performed and showed that the H-SOEC/DMR unit had the lowest exergy efficiency as a high-temperature exhaust gas was released.

Praseodymium doping in ceria-supported palladium nanocatalysts as an effective strategy to minimize the inhibiting effects of water during methane oxidation

The present study reports an improved design for Pd/Ce-Pr catalysts. Pd-impregnated nanostructured ceria-praseodymia catalysts with different compositions were comprehensively characterized and tested for dry and wet methane oxidation. The strong PdO-PrOx interaction, detected via XRD, TPR/TPO, Raman and HRTEM analyses, retains Pd mainly in its oxidized form in the materials with high praseodymium content, thus resulting in a lower activity. Conversely, the introduction of a limited amount of Pr in ceria allows to obtain a more active catalyst (2% of Pd supported on a mixed oxide with 10% of Pr) than the typical Pd/CeO2 systems. Hence, the simultaneous presence of Pd in its reduced and oxidized forms results to be a key factor for high activity. Additionally, the higher hydrophobicity of this sample, investigated through NMR and in situ FTIR, markedly reduces the H2O inhibition effect typical of Pd-based materials, paving the way for using this system in real applications.

Unraveling the effect of variable natural gas feedstock on an industrial ammonia process

Ammonia plays critical role as the second most produced chemical commodity with around 80% used in producing nitrogen-based fertilizer. Considering the decline of reserves of fossil-based feedstocks it is imperative to shift towards greener alternatives. However, such green ammonia processes are far from being economically viable. This makes natural gas-based ammonia synthesis the best available technology currently, but this faces critical difficulties as natural gas supply could widely vary due to declining reserve or changing sources, posing another key challenge to improve the efficiency of affected ammonia production.This study is the first to investigate the effect of variable natural gas composition (within the range of 83–99.99% vol dry methane; towards lean gas) on an industrial ammonia production process with maintained key operating parameters value such as steam to carbon ratio (S/C), hydrogen over nitrogen ratio (H/N), etc. The sensitivity analysis shows that sustained energy efficiency of the process is possible, confirming the conventional ammonia plant's ability to withstand changes in feedstock and fuel supply. In addition, lean gas yielded a positive impact on the raw material intensity and CO2 emissions with average reductions of 1.17% and 1.79% per each 4% methane content increase, respectively.

The CREC Fluidized Riser Simulator a Unique Tool for Catalytic Process Development

The CREC Riser Simulator is a mini-fluidized bench scale unit invented and implemented in 1992, at the CREC (Chemical Reactor Engineering Centre), University of Western Ontario The CREC Riser Simulator can be operated at short reaction times, in the 3 s to 20 s range. The present review describes and evaluates the original basic concept of the 1992-CREC Riser Simulator Unit, and the improved design of the 2019-CREC Riser Simulator. Both the initial and the enhanced units are specially engineered to allow the rigorous assessment of both catalyst performance and catalytic reaction kinetics. Kinetic parameters of relatively simple and accurate mathematical models can be calculated using experimental data from the CREC Riser Simulator. Since its inception in 1992, the CREC Riser Simulator has been licensed to and manufactured for a significant number of universities and companies around the world. Several examples of scenarios where the CREC Riser Simulator can be employed to develop fluidized bed catalytic and heterogeneous reactor simulations are reported in this review. Among others, they include (a) hydrocarbon catalytic cracking, (b) the catalytic conversion of tar derived biomass chemical species, (c) steam and dry catalytic methane reforming, (d) the catalytic oxydehydrogenation of light paraffins, (e) the catalytic desulfurization of gasoline, and (f) biomass derived syngas combustion via chemical looping. In this review, special emphasis is given to the application of the CREC Riser Simulator to TIPB (tri-iso-propyl-benzene) catalytic cracking and the light paraffins catalytic oxydehydrogenation (PODH).

Carbon Capture Utilization and Storage in Methanol Production Using a Dry Reforming-Based Chemical Looping Technology.

This further investigates the concept of gas switching dry reforming (GSDR) that efficiently converts the two major greenhouse gases (CO2 and CH4) into a valuable product (syngas) for gas-to-liquid (GTL) syntheses. The proposed GSDR is based on chemical looping technology but avoids external circulation of solids (metal oxides) by alternating the supply of reducing and oxidizing gas into a single fluidized bed reactor to achieve redox cycles. Each cycle consists of three steps where a metal oxide/catalyst is first reduced using GTL off-gases to produce CO2 (and steam) that is supplied to the next reforming step to produce syngas for GTL processes. The metal oxide is then reoxidized in the third step associated with heat generation (through the exothermic oxidation reaction of the metal oxide and air) to provide the heat needed for the endothermic dry methane reforming step. Experimental demonstrations have shown that a syngas H2/CO molar ratio between 1 and 2 suitable for methanol production could be achieved. A further demonstration shows that pressure has negative effects on gas conversion. Following the successful experimental campaign, process simulations were completed using ASPEN to show how the GSDR process can be integrated into a methanol (MeOH) production plant.

Cu supported on various oxides as a candidate catalyst for dry methane reforming in DIR-SOFCs systems

A series of Cu-support systems were tested as potential candidates for DIR-SOFC (Direct Internal Reforming SOFC) catalysts towards a dry reforming of methane (DRM). The various supports (α-Al2O3, CeO2, ZrO2, SrTiO3) with comparable specific surface area (SSA), and additionally γ-Al2O3 with SSA an order of magnitude larger than that of the other supports has been applied. The obtained Cu-support systems were characterized in terms of structure (XRD, XPS), microstructure (SEM), redox properties (TPR/TPOx), and next their catalytic activity and selectivity in DRM reaction were tested. All Cu-support materials show catalytic activity in DRM reaction, but only activity of Cu–SrTiO3 is high (due to the incorporation of Cu into SrTiO3 structure). The catalytic activity of other materials depends on the copper oxidation state (Cu2+ and Cu+). The highest catalytic activity in DRM process was obtained for Cu–AlO(OH) catalyst thanks to an order of greater SSA than in the case of other systems.

Biogas potential of cup plant and willow-leaf sunflower biomass

Perennial herbaceous crops (PHC) are increasingly often perceived as a competitive biomass source or as a co-substrate for biogas plants. The aim of the study was to determine the dry biomass yield, the biogas and methane production efficiency, potential energy yield and economic analysis for two PHC species, depending on the fertilisation type and nitrogen level in three successive cultivation years. The mean dry matter yield of Silphium perfoliatum was significantly higher (by 19.4%) compared to the mean yield of Helianthus salicifolius. The application of organic (digestate) and mineral fertilisers and a higher nitrogen level have significantly contributed to increasing dry matter yield compared to the plots without fertilisation. However, fertilisation have no significant impact on the biogas or methane efficiency. The highest biogas efficiency for S. perfoliatum and H. salicifolius biomass was 372.8 m3 Mg−1 DM and 280.9 m3 Mg−1 DM, respectively. The biogas, methane and energy potential yield of S. perfoliatum was significantly higher (over 50%) compared to the values of H. salicifolius. Meanwhile, the potential income from energy generation from S. perfoliatum was higher by 482%. Therefore, S. perfoliatum proved to be a more prospective PHC species as a biomass source for biogas plants.

Investigation of H2 production via an integrated pathway of consecutive CO oxidation and dry methane reforming in the presence of Co3O4@HNTs catalyst

Investigation of H2 production via an integrated pathway of consecutive CO oxidation and dry methane reforming in the presence of Co3O4@HNTs catalyst

Bifunctional metal doping engineering of Ni-supported alumina catalyst for dry methane reforming

Increasing the basicity of catalysts using basic promoters is known to be effective in retarding rapid coke deposition on catalysts, which is the biggest obstacle to the commercialization of dry methane reforming (DRM). In this study, we investigated the doping of various basic metals (Mg, Ca, Sr, Ba, and La) in nickel-supported alumina catalysts and found that Sr, an element that has drawn less attention than others, has the greatest effect on coke formation resistance. The highest coke resistance attributes more to the small nickel particle size, high reducibility, and strong interaction between the active metal and support, than to the basicity of the catalysts. Furthermore, except for Mg, metal doping was efficient for improving the thermal stability of the catalysts, which is beneficial for maintaining the nickel particle size and mesoporous structure, leading to long-term reaction stability. Under the reaction conditions of accelerated coke formation, the catalytic activity of Ni/Sr-MA was maintained for 50 h without performance decline and coke formation-mediated reactor blockage. This discovery offers new opportunities to develop effective nickel-based DRM catalysts with coke resistance by comprehensively considering the nickel particle size, acidity/basicity, reducibility, and strong interaction between the active metal and the support.

Development of CoMo-X catalysts for production of H2 and CNTs from biogas by integrative process

In this study, catalytic conversion of biogas into hydrogen and carbon nanotubes is investigated using an integrative process of dry reforming and methane decomposition. The catalytic improvement of cobalt catalysts promoted with various promoters: Mo, Ce, Zr, W, and Ca, is examined to discover the best combination that is resistant to a metal sintering. The addition of Mo shows an improved catalyst stability due to an enhanced metal-support interaction, avoiding metal sintering. The current process shows a remarkable CO2 conversion of 99.4% and a high CH4 conversion of 95.8%, while the gaseous products comprise of H2 up to 77%v/v at 900 °C, GHSV of 4500 ml/g-h. The long-term stability test for 7 h shows that the catalysts promoted with Mo, Zr, and W could provide almost complete CO2 conversion at 900 °C and under a high GHSV of 45,000 ml/g-h. The analysis of spent catalysts shows that deposited carbon composed of well-structured multi-walled carbon nanotubes (MWCNTs) with high graphitization (IG/ID = 2.14), compared to the commercial CNTs (IG/ID = 0.74). The as-synthesized CNTs could achieve 91%w/w purity without any purification. The process test at high temperature of 1000 °C, provides higher graphitization (IG/ID = 3.76) with compensation of lower yield of CNTs. This integrative process demonstrates a promising route to completely convert a renewable biogas into high-value products such as hydrogen and carbon nanotubes with less production of wastes.

PH buffering additives mitigate the inhibition of thermophilic dry methane fermentation

pH buffering additives mitigate the inhibition of thermophilic dry methane fermentation

Future Paradigm of 3D Printed Ni-Based Metal Organic Framework Catalysts for Dry Methane Reforming: Techno-economic and Environmental Analyses.

Dry reforming of biogas is referred as an attractive path for sustainable H2 production over decades. Meanwhile, in the Malaysian context, the abundance of palm oil mill effluent (POME) produced annually is deemed as a potential renewable source for renewable energy generation. Conventionally, nickel (Ni) is the most common catalyst used in the industrial-scale dry reforming of methane (DRM) to yield H2, but it is subject to the drawbacks of sintering and deactivation after a long reaction time at high temperatures (>500 °C). Therefore, this work aims to provide an insight on the feasibility of the application of modified Ni-based catalysts in DRM, specifically in the economic and environmental aspects. From the benchmarking study of various Ni-based catalysts (e.g., bimetallic (Ni-Ce/Al2O3), alumina support (Ni/Al2O3), protonated titanate nanotube (Ni-HTNT), and unsupported), the Ni-MOF catalyst, notably, had proven its prominence in both economic and environmental aspects on the same basis of 10 tonnes of H2 production. The MOF-based catalyst not only possessed a better economic performance (net present value 61.86%, 140%, and 563.08% higher than that of Ni-Ce/Al2O3, Ni/Al2O3, and Ni-HTNT) but also had relatively lower carbon emissions (13.18%, 20.09%, and 75.72% lower than that of Ni/Al2O3, Ni-HTNT, and unsupported Ni). This work also accounted for 3D printing technology for the mass production of Ni-MOF catalysts, where the net present value was 2 to 3% higher than that of the conventional production method. Additionally, sensitivity analysis showed that the H2 price has the greatest impact on the feasibility of DRM as compared to other cost factors.

Improving Anti-Coking Properties of Ni/Al2O3 Catalysts via Synergistic Effect of Metallic Nickel and Nickel Phosphides in Dry Methane Reforming

A series of NiP-x/Al2O3 catalysts containing different ratio of metallic nickel to nickel phosphides, prepared by varying Ni/P molar ratio of 4, 3, 2 through a co-impregnation method, were employed to investigate the synergistic effect of metallic nickel-nickel phosphides in dry methane reforming reaction. The Ni/Al2O3 catalyst indicates good activity along with severe carbon deposition. The presence of phosphorus increases nickel dispersion as well as the interaction between nickel and alumina support, which results in smaller nickel particles. The co-existence of metallic nickel and nickel phosphides species is confirmed at all the P contained catalysts. Due to the relative stronger CO2 dissociation ability, the NiP-x/Al2O3 catalysts indicate obvious higher resistance of carbon deposition. Furthermore, because of good balance between CH4 dissociation and CO2 dissociation, NiP-2/Al2O3 catalyst exhibits best resistance of carbon deposition, few carbon depositions were formed after 50 h of dry methane reforming.

CO2 utilization in methane reforming using La-doped SBA-16 catalysts prepared via pH adjustment method

In this work, lanthanum-combined silica mesoporous (SBA-16) supported Ni-based catalysts are synthesized and examined for synthesis gas (syngas) production in the dry methane reforming (DMR) process. The pH-adjusted hydrothermal technique has been used to modify the mesoporous silica-based support, which has been then impregnated by Ni particles. The pH value had a substantial impact on creating well-ordered mesostructures and lanthanum ion replacement inside the SBA-16 structure. Therefore, at the ideal pH of 3.80, a zeolite-like mesostructure of Si-La has been produced. Thus, La2O3 species have been inserted in the SBA-16 structure, favoring a larger dispersion of impregnated Ni particles of lower dimensions. In addition to the pH modification during the synthesis step, the effects of lanthanum loading and Ni weight percentage variation on the catalytic performance as well as the physicochemical analyses of the catalysts have been also explored. The calcined catalysts have been tested in the DMR process in the temperature range of 600–750 °C. Furthermore, the coke resistance, activity, and structural changes of optimal catalysts have been studied over 11 h. The results showed that the 15Ni/40La-SBA16(3.80) catalyst performs the best structural characteristics and catalytic activity.

GEOLOGICAL AND GEOCHEMICAL FEATURES OF AN OIL FIELD OF PRECASPIAN REGION

This article highlights the geological and geochemical features of the oil field of the Caspian region of the territory of Kazakhstan. The ways of hydrocarbon migration, which were carried out in the direction of the southern steeper part of the Arystanov stage, are described. All the studies carried out over the previous years have shown that the composition of dispersed organic matter (kerogen) contained in Jurassic and Triassic sediments has a predominantly mixed, mixtinite composition. The factor causing long-range migration may be faults, including a high-amplitude fault in the junction zone of the Kosbulak trough with the Akkulkovsko-Bazaysky ledge and the Aral-Kyzylkum fault, to which the deepest parts of the Kosbulaksky and Barsakelmessky bends are confined, and rock fractures in various porous and permeable reservoir rocks can also serve. The presence of significant reserves of dry methane gas deposits in the Paleogene of the Akkulkovsko-Bazaysky ledge and the established manifestations of gas in the northern half of the Kyzyloysky shaft in Upper Cretaceous sediments are associated with their vertical and lateral migration within these ledges, including vertical along the faults. The unconformity surface at the foot of the Lower Jurassic sediments provides the development of organic life, plant growth, and clay residues deposited above these unconformities become good source rocks. According to all geochemical indicators, the Middle Jurassic rocks are oil-producing that are located in a favorable middle zone of mesocatagenesis. The main volumes of oil reserves discovered on the territory of Northern Ustyurt were found in the sediments of the Middle Jurassic. The results of geochemical studies in the future will allow basin modeling to be carried out with greater accuracy.

Syngas Production by Dry Methane Reforming over Alumina‐Supported Noble Metals and Kinetic Studies

AbstractDry reforming of methane (DRM) provides valuable syngas from two greenhouse gases, CH4 and CO2. Three alumina‐supported noble metals, Ru, Pt, and Pd, were used as catalysts for the DRM process. Using CO2/CH4 mixtures in the range of 0.5–2 mol mol−1, catalyst performance was assessed in an integral fixed‐bed reactor between 773 and 1073 K. All catalysts were stable for at least 10 h. The DRM kinetics was studied in a differential reactor in the range of 848–898 K, using the power law model. The apparent activation energy values for the consumption of CH4 (86, 89, and 95 kJ mol−1) and CO2 (84, 86, and 91 kJ mol−1) over Ru/Al2O3, Pt/Al2O3, and Pd/Al2O3 as catalysts were found. Several kinetic models of the Langmuir‐Hinshelwood type were considered. A pathway with slow surface reaction between CH4 and CO2 chemisorbed on different types of active sites was found to be most suited to describe the kinetic data.

Mesoporous silica-encaged ultrafine ceria–nickel hydroxide nanocatalysts for solar thermochemical dry methane reforming

Reforming of methane to produce synthesis gas for the Fischer–Tropsch process provides an alternative to fossil fuels. Silica-encaged ceria–nickel hydroxide catalysts were produced by an in situ synthesis method to obtain ultrafine bimetallic species dispersed evenly within the mesoporous silica matrix. Dry reforming and reduction-oxidation cycling was undertaken with the materials. Catalysts with high content of nickel showed good activity during dry reforming, with conversions rates close to equilibrium in equimolar conditions. Insignificant deactivation of the catalysts was observed over 5 h and 50 h of reaction at 900 °C. Syngas production via reduction–oxidation cycling was shown to be insignificant as compared to continuous catalytic reforming.

Biogas reforming over La-promoted Ni/SBA-16 catalyst for syngas production: Catalytic structure and process activity investigation

Biogas, a mixture of CO2/CH4, is reasonable for conversion to syngas (H2/CO) by dry methane reforming (DMR) reaction. The modification of Ni/SBA-16 with a lanthanum promoter using the co-impregnation technique is investigated in this study. The temperature of reaction (600–750 °C), La loading (3.85–11.56 wt%), and Ni loading (10–30 wt%) are the parameters that are varied for maximizing reaction conversions. The synthesized catalysts and SBA-16 supporting material were characterized by several methods before and after reaction. According to the analysis, the existence of La2O3 particles on the catalyst's surface has decreased the particle sizes, as well as enhanced their dispersion. Therefore, the maximum CH4 conversion of 94.21%, CO2 conversion of 90.12%, H2 yield of 90.53%, and H2/CO molar ratio of 2.03 are achieved using 20Ni-5.78La/SBA16 at 700 °C. Besides, this catalyst showed lower deposited coke and higher stability compared with other synthesized catalysts.

Syngas Generation Process Simulation: A Comparative Study

Methane reforming processes are of great importance for both the reduction of this greenhouse gas concentration in the atmosphere and for hydrogen production for energetic or chemical synthesis purposes. The use of Biogas in substitution for methane in reforming processes still provides a solution for the recovery of organic waste capable of producing Biogas. However, an in-depth analysis of the advantages of this substitution from the point of view of process yield is still lacking. Thus, the main contribution of the present research is the focus given to the comparison between methane and biogas as a reactant for the dry and steam reforming processes. In this work, a computational comparison of syngas production processes was performed, considering the system within the open-loop control. The software Aspen Hysys was used based on the minimization of Gibbs free energy in equilibrium. The parameters studied were: molar ratio of reagents (1-5), temperature (600-1000 °C), and pressure (1-5 bar). Dry methane reforming and steam methane reforming units were simulated, as well as both units using Biogas as a methane source. The plant was built in the simulator, and the results obtained indicated that high values in the molar ratio of CO2/CH4, CO2/Biogas, H2O/CH4, and H2O/Biogas, high temperatures, and low pressures favor the maximum conversion of methane. The use of Biogas in replacement of pure methane in the reform process proved to be advantageous for favoring the synthesis gas production reaction, besides adding value to a residue.