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The detailed experimental studies of the autothermal and steam reforming of model mixtures simulating the composition of commercial diesel fuel were carried out over Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl wire mesh honeycomb catalytic modules. The components of the diesel surrogates were n-hexadecane, o-xylene, and naphthalene as model compounds of aliphatics, mono-aromatics and diaromatics, respectively. It was shown that low reaction rate of diaromatics steam reforming facilitated increasing concentration of C1–C5 hydrocarbon by-products (primarily ethylene) in the gas phase, as well as formation of polyaromatic compounds by concurrent condensation reaction. These undesirable processes were responsible for increasing catalyst coking. Monoaromatic constituents hadn't any significant effect on the progress of undesirable side-reactions during autothermal and steam reforming of diesel surrogates.

A mathematical model for the catalytic autothermal reforming (ATR) reaction of synthetic crude glycerol to hydrogen in a fixed bed tubular reactor (FBTR) and over an in-house developed metal oxide catalyst is presented in this work. The heterogeneous model equations account for a two-phase system of solid catalyst and bulk feed gas. Also, the ATR of crude glycerol reaction scheme and intrinsic kinetic rate model over an active, selective, and stable nickel-based catalyst were integrated in the developed model. Also, the model was validated using experimental data generated in our labs for the ATR of synthetic crude glycerol. The modelling results adequately described the detailed gas product composition and distribution, temperature profiles, and conversion propagation in the axial direction of the fixed bed reactor over a wide range of reaction temperature (773−923 K) and weight-time (12.71−158.23 g cat·min·molC−1). The crude glycerol conversion predicted with the model showing a close resemblance to those obtained experimentally with an average absolute deviation (AAD) of less than 8%. The maximum crude glycerol conversion and hydrogen yield were found to be 92% and 3 mol hydrogen/mol crude glycerol, respectively. Also, the gas product concentration profile in the reactor was adequately described (90%) accuracy with a hydrogen concentration of 39 vol%.

Solar energy is the source of energy required for the dry methane reforming (DMR). In the high temperature field induced by concentrated solar energy, the spatial distribution of radiation intensity has a significant impact on the solar thermochemical performance. Based on principle of minimum Gibbs free energy (Gmin), the idea of regulating radiation field to match solar thermochemical energy conversion on-demand is proposed. To improve solar thermochemical conversion efficiency, biomimetic hierarchical porous structure is introduced as solar thermochemical reactor, which can optimize both the radiation field and temperature field. The analysis model of solar driven DRM is established, combined with user-defined functions (UDFs). The effects of pore diameter combinations along the direction of L and R on the reforming properties are studied. The results show that by designing biomimetic hierarchical porous structure, the temperature of solar thermochemical reactor can approach the thermodynamic temperature (1050 K), and finally the methane conversion is improved by up to 7%.

The electrochemical activation of a Pt-KβAl2O3 catalytic system is studied for hydrogen production from ethanol. The in-situ intercalation of potassium ions onto the catalyst surface under negative polarization leads to hydrogen activation and an increase in the production rate under all explored conditions, observing a reproducible, controllable and reversible effect. Under ethanol partial oxidation conditions, the ions migration promotes oxidation dehydrogenation route vs. ethanol dehydration one. Moreover, the steam addition is evaluated through different reaction conditions: steam reforming, partial oxidation and autothermal reforming. The steam reforming reaction exhibits the highest initial catalytic activity; although a strong deactivation of the catalyst occurs due to carbonaceous species deposition. Comparing partial oxidation and autothermal reforming, the latter one presents the highest catalytic activity and the strongest electrochemical activation effect. These findings contribute to the Electrochemical Promotion of Catalysis phenomenon application to operando tuning the catalyst conversion towards hydrogen production, therefore expanding its application to hydrogen technology., Se estudia la activación electroquímica de un sistema catalítico Pt-KβAl 2 O 3 para la producción de hidrógeno a partir de etanol. La intercalación in situ de iones de potasio en la superficie del catalizador bajo polarización negativa conduce a la activación del hidrógeno y a un aumento en la tasa de producción en todas las condiciones exploradas, observando un efecto reproducible, controlable y reversible. En condiciones de oxidación parcial de etanol , la migración de iones promueve la vía de deshidrogenación por oxidación frente a la deshidratación de etanol. Además, la adición de vapor se evalúa a través de diferentes condiciones de reacción: reformado con vapor , oxidación parcial y reformado autotérmico . La reacción de reformado con vapor presenta la mayor actividad catalítica inicial ; aunque se produce una fuerte desactivación del catalizador debido a la deposición de especies carbonosas. Comparando la oxidación parcial y el reformado autotérmico, este último presenta la actividad catalítica más alta y el efecto de activación electroquímica más fuerte. Estos hallazgos contribuyen a la aplicación del fenómeno de la promoción electroquímica de la catálisis para operar la conversión del catalizador hacia la producción de hidrógeno, por lo tanto, expandiendo su aplicación a la tecnología del hidrógeno .

High surface area mixed oxide 8.7% NiO-CeO2 nanoparticles (122 m2/g; 6–7 nm) were prepared using a reversed microemulsion method, and were tested for dry methane reforming (DRM). The catalytic activity of these nanoparticles remains stable under the severe conditions of DRM (700 °C), and they show better carbon resistance than conventional NiO-CeO2 catalysts prepared without control of the size. The activity and selectivity of nanoparticles and reference catalyst are similar, but nanoparticles reduce by 63% the accumulation of carbon during the DRM tests, which is a key feature for this reaction. XPS and H2-TPR suggest that the improved carbon resistance of the nanoparticles is the better interaction and cooperation between NiO and CeO2 mixed phases. In nanoparticles, the participation of cerium cations in the redox processes taking place during DRM stabilize cationic species of nickel. On the contrary, the catalyst prepared without control of the size suffered segregation of Ni during DRM reaction, and segregated Ni explains the higher catalytic formation of carbon. Project supported by the Generalitat Valenciana (Project PROMETEO/2018/076; ACA GRISOLIAP/2017/185; EBG APOSTD/2019/030), MINECO (CTQ2015-67597-C2-2-R), MICINN (PID2019-105960RB-C22) and European Union FEDER funds.

A hydrogen concentration from ethanol-gasoline blends reforming processes plays a role in exhausted gas recirculation (EGR) that enhanced engine performance and aftertreatment system of gasoline direct injection (GDI) engine. An equilibrium model is widely used as a primary tool to determine a level of hydrogen content from reforming process. Thus, in this work, the equilibrium analysis of hydrogen production is investigated using STANJAN program. Three main reactions (Partial Oxidation Reforming (POx), steam reforming (SRM) and autothermal reforming (ATR)) are studied here. Three commercial ethanol-gasoline blends are studies here (E10, E20 and E85). The effect of reaction temperature, steam to fuel ratio (S/F) and oxygen to fuel ratios (O2/F) are investigated. The results show that the optimum condition for POx is achieved at O2/F ratio of 3 for E10 and E20 and 0.75 for E85. For SRM, the optimum condition for H2 production at temperature 200–500 °C are achieved with S/F ratio of 10–12 for E10 and E20, while E85 can be obtained at S/F ratio of 6–8. Under these conditions, the maximum hydrogen yield (∼30 vol%) are reached with temperature 500 °C. In case of ATR, the highest H2 yield (approximately 25 vol%) is achieved at temperature 500 °C with S/F ratio of 8 for E10 and E20 fuels and 4 for E85 fuel. The highest H2 yields from real exhausted gas reforming are 42 to 55 % vol. Thus, this possibility of on-board hydrogen production via gasoline - ethanol fuel blends reforming operates in GDI engine.

Perovskites with the structural formula La1-xCexNi1-yAlyO3 (x = 0 y = 0; x = 0.05 y = 0; x = 0.05 y = 0.2 and x = 0.05 y = 0.5) were studied in the dry methane reforming in presence of oxygen or Oxy-Dry (OD). The materials were synthetized by the amorphous citrate method and characterized by XRD, in situ XRD under hydrogen and reactional (OD) atmospheres, TPR-H2, XRF, TPSR-OD, TPSR−CH4, TEM, HRTEM and TPO techniques. The catalytic performance was evaluated during 16 h of reaction, with a [CH4/CO2/O2] ratio = 4:2:1, at 800 °C and spatial velocity of 210.000 NL.h−1.kgcat−1. The addition of aluminum and cerium promoted an increase in the catalyst resistance to carbon poisoning, however, the higher the aluminum content was, the lower the reducibility of the perovskites and the nickel particle size. The La0.95Ce0.05Ni0.5Al0.5O3 sample showed the best results, with a maximum CH4 and CO2 conversion of 85 % and 86 % respectively and the higher syngas yield (45 % for CO and 48 % for H2). This sample presented the lowest Ni° particle size and carbon deposition after 16 h time on stream. No sign of deactivation was found for all the studied catalysts, showing the superior properties of catalysts prepared through perovskite-like mixed oxides.

The potential of Ni–Cu–Mn spinels as methane reforming catalysts for hydrocarbon-fueled solid oxide fuel cell (SOFC) applications is highly dependent on its catalytic properties, particularly reducibility. The reducibility of a spinel-structured catalyst is often correlated with its structural properties and fabrication processes. In this work, the structural properties and reducibility of a Ni–Cu–Mn spinel catalyst was evaluated on the basis of mixing time during the glycine–nitrate process. Phase analysis results showed that Ni0.4Cu0.6Mn2.0O4 and (Cu, Mn)3O4 in normal or inversed spinel structures were observed in GNP-produced Ni–Cu–Mn spinel catalyst powders. Distortion in inverse spinel structures enhanced the reducibility of the spinel catalyst. Morphological analysis results showed that complete nitrate binding occurred at a minimum mixing time of 24 h and resulted in homogenous particle size distribution and uniform elemental distribution. Furthermore, the Ni–Cu–Mn spinel catalyst produced after 24 h of mixing was fully reduced at 450 °C. The reducing pattern of the Ni–Cu–Mn spinel catalyst produced after 24 h of mixing time showed strong metal–support interaction and the fast adsorption of reactants. These effects were due to either the distribution of divalent cations in octahedral sites or large amounts of bulk pores. In conclusion, a minimum mixing time of 24 h is sufficient to produce the desired structural properties and reducibility of Ni–Cu–Mn spinel catalysts for SOFC applications.

In this study, new results of comparative research on autothermal reforming(ATR) of biofuels (hydrodeoxygenated biodiesel and long- stored biodiesel) over composite RhSC catalysts (0.24 wt.% Rh supported on structured Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl carrier) were obtained. The impact of fuel chemical composition on the catalyst performance was discussed. Hydrodeoxygenated biodiesel mainly consisted of heptadecane, other normal alkanes and small amounts of alkenes together with a portion of unreacted fatty acid ethers. RhSC exhibited syngas productivity of about 2.5 m3Lcat−1 h−1 (STP) at complete conversion of hydrodeoxygenated biodiesel without considerable by-products formation, at molar ratios O2/C = 0.54, H2O/C = 3, T =750 °C and GHSV =5000 h−1. The catalyst exhibited stable operation and no coke formation for at least 90 h on stream. Biodiesel after nine years storage, which was used in this study, contained methyl esters of saturated and unsaturated fatty acids and a large proportion of polymeric compounds. It was successfully demonstrated that even this aged biodiesel can be converted to synthesis gas over the developed Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl structured catalyst. Further optimization of the catalyst and reaction conditions (higher temperature, lower GHSV, catalyst doping by promoters) is required for reaching efficient reforming of the aged biodiesel. Nevertheless, it was demonstrated that biodiesel and hydrodeoxygenated biodiesel, which combine high energy density and renewability, were very attractive biofuels for fuel cell-based power unit applications.

The life cycle cost, environmental, and energy performances of gas turbine (GT) hybridization with two high-temperature fuel cells, solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC), were investigated in detail. The purpose of the present study is to assess the feasibility of the hybridization based on a throughout comparative investigation between 10-MW GT, MCFC-GT, and SOFC-GT systems in their optimum conditions. A model for SOFC, MCFC, and combustion processes was developed using the Gibbs minimization method through Lagrange multipliers. This model calculates unreformed methane during the methane reforming process occurring within the fuel cells. In addition, it calculates pollutant gases emission rates caused by combustion (i.e. NO, NO2, CO2). The economic analysis of the systems was based on the life cycle-costing P1-P2 method which considers fuel and investment costs. The Genetic algorithm was utilized for single- and multi-objective optimization purposes in different cases. Also, a comprehensive sensitivity analysis was conducted to compare the three systems in their optimum conditions to guarantee results obtained from the optimization scenario. The findings revealed that the SOFC was the best candidate for the GT system hybridization. This hybridization reduced the system investment and fuel costs, and CO2 and NO emissions in the fixed power conditions. The maximum energy efficiency of the GT, MCFC-GT, and SOFC-GT systems was obtained to be 43.8%, 53.8%, and 70.3%, respectively. The minimum values for the CO2 emission of the stand-alone GT, the hybrid MCFC-GT, and the hybrid SOFC-GT systems were 460.8 kg/MWh, 367.9 kg/MWh, and 280.4 kg/MWh, besides NO emission was calculated 13.9 kg/MWh, 1.3 kg/MWh, and 1.2 kg/MWh, respectively. The least life cycle cost of the stand-alone GT, the hybrid MCFC-GT, and the hybrid SOFC-GT systems was 163.6, 160.7, and 106 million dollars, respectively.

Ordered mesoporous MgAl2O4 support was synthesized by one-pot evaporation-induced self-assembly method with block copolymers. Nanocomposite catalysts were prepared by loading this support with PrNi0.9Ru0.1O3 perovskite or Ni + Ru-doped Ce0.35Zr0.35Pr0.3O2 fluorite oxides. Their texture, structure, surface properties and reactivity have been studied by combination of modern structural, spectroscopic and kinetic methods. Suppression of MgAl2O4 support acidity, strong interaction of small Ru-Ni alloy nanoparticles with the surface layers of this support modified by perovskite and fluorite oxides with a high oxygen mobility and reactivity provide a high activity and stability to coking and sintering of these catalysts in all studied reactions of methane and ethanol transformation into syngas. Ni + Ru/Ce0.35Zr0.35Pr0.3O2/MgAl2O4 active component loaded on honeycomb Fechraloy foil substrate demonstrated a high performance and stability to coking in autothermal natural gas oxi-dry reforming, ethanol steam reforming and autothermal reforming of ethyl acetate in concentrated feeds promising for the practical application.

In this study, combustion and emission characteristics of methane mixed with steam (CH4/H2O) and the products of methane reforming with steam (CO/H2/H2O) were compared. Four fuel compositions were analysed: CH4+H2O, CH4+2H2O, and products of complete methane reforming in these mixtures, respectively. A comparison was carried out through the numerical model created via Ansys Fluent 2019 R2. A combustion process was simulated using a non-premixed combustion model, standard k-ϵ turbulence model and P-1 radiation model. The combustor heat capacity for interrelated fuel compositions was kept constant due to air preheating before combustion. The inlet air temperature was varied to gain a better insight into the combustion behaviour at elevated temperatures. The effect of steam addition on the emission characteristics and flame temperatures was also evaluated. NOx formation was assessed on the outlet of the combustion zone. The obtained results indicate that syngas has a higher combustion temperature than methane (in the same combustor heat capacity) and therefore emitted 27% more NOx comparing to methane combustion. With the air inlet temperature increment, the pollutant concentration difference between the two cases decreased. Steam addition to fuel inlet resulted in lesser emissions both for methane and syngas by 57% and 28%, respectively. In summary, syngas combustion occurred at higher temperature and produced more NOx emissions in all cases considered.

A solid oxide fuel cell (SOFC) has wide stationary and mobile application prospects due to its high efficiency and fuel flexibility. The SOFC system’s performance depends on the reforming option and system design. In this paper, we designed a novel SOFC auxiliary power unit (APU) system with ethanol on-board reforming aiming at vehicle application. The thermodynamic analysis is employed to evaluate the ethanol-fueled SOFC performance of different reforming options with a metal-supported SOFC working at 600 °C and a 0.3 A/cm2 current density. The electrical efficiency of the SOFC can reach a maximum of 50% with ethanol autothermal reforming. Under the optimal reforming option and operating conditions, the conceptual SOFC-APU system design is identified with the trade-off between system efficiency and ethanol flow from the startup and stable operation phase. The results show that the system efficiency of 44.4% can be achieved with a 0.42 g/s ethanol flow at the startup phase. During the stable operation, the electrical efficiency and exergy efficiency of the SOFC-APU system can reach 55.4 and 77.1% with a 70% anode gas recirculation ratio, respectively.

The Rh/Ce0·75Zr0·25O2–δ-ƞ-Al2O3/FeCrAl structured catalytic blocks of length 10, 20, and 60 mm were prepared and tested in the reactions of steam and autothermal reforming of n-hexadecane. It was found in a series of experiments on hexadecane steam reforming with the catalyst heating solely through the reactor wall that the complete conversion of hexadecane at a furnace temperature below 750 °C was not achieved even at GHSV = 10,000 h−1. Under these conditions, the formation of carbon on the catalyst surface was observed. At the reactor wall temperature of 800 °C, the complete conversion of hexadecane was achieved even in the 10 mm long catalytic block (GHSV = 60,000 h−1), accompanied by the formation of various intermediate light hydrocarbons. To achieve complete conversion of these intermediate compounds (mainly 1-alkenes), it is necessary to carry out the steam reforming reaction at GHSV = 10,000 h−1. At hexadecane autothermal reforming, heat is supplied to the reaction zone by exothermic oxidation reaction, which makes this process more efficient. In experiments with the use of additional external heat supply through the reactor wall, complete conversion of hexadecane occurred at GHSV = 120,000 h−1. To convert all by-products (mainly 1-alkenes) and achieve a nearly thermodynamic equilibrium distribution of the main reaction products (H2, CO, CO2), the reaction should be carried out at GHSV = 20,000 h−1. Without external heat supply, hexadecane conversion decreased, while the content of light hydrocarbons in the reaction products increased. An increase in the inlet amount of oxygen helps to compensate the heat losses in the reactor and to increase the efficiency of hexadecane autothermal reforming. The performed experiments allow better understanding of the processes which occur during the steam and autothermal reforming of diesel.

An investigation of the effect of catalyst separation in stratified autothermal reforming was conducted. A reactor containing two catalyst beds - a platinum group metal monolith followed by a pelletized copper-based steam reforming catalyst - was investigated under four different configurations corresponding to different distances between the catalyst beds. Heat shields were utilized in some trials to promote reactant mixing and increase radial heat transfer through the reactor. Reactor performance, as measured by conversion, hydrogen yield, and selectivity was quantified for each configuration. Results confirm that the reaction is heat transfer limited, with the short-distance, high-temperature configuration corresponding to an improved reactor performance. This was indicated by a 4–5% drop in methanol conversion as well as in the hydrogen yield and selectivity upon the addition of spacing between the catalysts. Visual inspection of the catalyst revealed suspected signs of potential degradation due to high temperatures, indicating the need for longer-duration experiments to determine the long-term effects of sustained high temperatures on catalyst performance.

The work is devoted to experimental studies and construction of a mathematical model of n-hexadecane (as the simplest diesel surrogate) reforming over Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl wire mesh honeycomb catalytic module in auto-thermal reforming (ATR) and steam reforming (SR) modes. Experiments were performed using the scalable catalytic modules with recurrent meshy channeled internal geometrical structure. This provided the accurate reproduction of mass transfer limitations and accompanying homogeneous reactions, thus significantly simplifying the following scale-up procedures. Impossibility to apply simple isothermal reactor models was compensated by application of CFD modelling for reproduction of internal distribution of temperature, fluid velocities and composition inside the catalyst module. The earlier proposed reaction scheme was supported by additional reactions to account for the formation of light C2-C5 hydrocarbons. The proposed model provides good description of both ATR and SR process modes, at the same time demonstrating significant difference between them. The proposed model may be used for development, scale-up and optimization of catalytic reformers using SR and ATR modes and their combination for processing diesel and similar liquid hydrocarbon fuels.

In this study a numerical analysis of hydrogen production via an autothermal reforming reactor is presented. The endothermic reaction of steam methane reforming and the exothermic combustion of methane were activated with patterned Ni/Al2O3 catalytic layer and patterned Pt/Al2O3 catalytic layer, respectively. Aiming to achieve a more compacted process, a novel design of a reactor was proposed in which the reforming and the combustion catalysts were modeled as patterned thin layers. This configuration is analyzed and compared with two configurations. In the first configuration, the catalysts are modeled as continuous thin layers in parallel, while, in the second configuration the catalysts are modeled as continuous thin layers in series (conventional catalytic autothermal reactor). The results show that the pattern of the catalyst layers improves slightly the hydrogen yield, i.e. 3.6%. Furthermore, for the same concentration of hydrogen produced, the activated zone length can be decreased by 38% and 15% compared to the conventional catalytic autothermal reforming and the configuration where the catalysts are fitted in parallel, respectively. Besides, the oxygen consumption is lowered by 5%. The decrement of the catalyst amount and the oxygen feedstock in the novel studied design lead to lower costs and compact process. © 2021 Hydrogen Energy Publications LLC

Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl and Rh/Ni–MgO/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl FeCrAlloy wire mesh supported catalysts were prepared via multistep procedure. They were characterized by XRD, SEM and TEM techniques. A comparative study of autothermal reforming (ATR) of isooctane and simulated gasoline (blends of isooctane, ortho-xylene and naphthalene) over Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl and Rh/Ni–MgO/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl was performed. Both catalysts showed excellent performance in ATR of isooctane at molar ratios of O2:C = 0.51 and H2O:C = 2.59, T = 750°С and GHSV = 10000 h−1. In the ATR of isooctane – o-xylene blend in presence of Rh–Ni-containing catalyst carbon formation was observed. Rh-containing catalyst demonstrated rather good activity and stability even in the case of isooctane – o-xylene – naphthalene blend.

The paper presents an analysis of the main catalysts and technologies applied for industrial conversion of natural gas to syngas, which is further used to produce ammonia, methanol and hydrogen. The analysis reveals the major trends in their development aimed to reduce the consumption of energy and resources; technological schemes of the processes as well as the catalysts and sorbents used in different steps of methane reforming and steam conversion of CO are described.

Nowadays, the efficient and cleaner utilization of coal have attracted wide attention due to the rich coal and rare oil/gas resources structure in China. Coal chemical looping gasification (CCLG) is a promising coal utilization technology to achieve energy conservation and emission reduction targets for highly pure synthesis gas. As a downstream product of synthesis gas, methyl methacrylate (MMA), is widely used as raw material for synthesizing polymethyl methacrylate and resin products with excellent properties. So this paper proposes a novel system integrating MMA production and CCLG (CCLG-MMA) processes aiming at “energy saving and low emission”, in which the synthesis gas produced by CCLG and purified by dry methane reforming (DMR) reaction and Rectisol process reacts with ethylene for synthesizing MMA. Firstly, the reaction mechanism of CCLG is investigated by using Reactive force field (ReaxFF) MD simulation based on atomic models of char and oxygen carrier (Fe2O3) for obtaining optimum reaction temperature of fuel reactor (FR). Secondly, the steady-state simulation of CCLG-MMA system is carried out to verify the feasibility of MMA production. The amount of CO2 emitted by CCLG process and DMR reaction is 0.0028 (kg CO2)−1·(kg MMA)−1. The total energy consumption of the CCLG-MMA system is 45521 kJ·(kg MMA)−1, among which the consumption of MMA production part is 25293 kJ·(kg MMA)−1. The results show that the CCLG-MMA system meets CO2 emission standard and has lower energy consumption compared to conventional MMA production process. Finally, one control scheme is designed to verify the stability of CCLG-MMA system. The CCLG-MMA integration strategy aims to obtain highly pure MMA from multi-scale simulation perspectives, so this is an optimal design regarding all factors influencing cleaner MMA production.

During the last few decades, the global energy requirement is soaring significantly due to the rise of global population and economic development. This resulted in colossal release of CO2 and CH4, emissions into the atmosphere referred as greenhouse gases (GHGs), which poses a detrimental effects for the environment. One of the sustainable solutions to curb emissions of GHGs into the atmosphere is efficient utilization of syngas in order to produce useful chemicals and fuels. A comprehensive review is presented to highlight the capability of Ni-based catalysts in methane reforming through the application of both steam and dry routes referred to as bi-reforming of methane (BRM). Ni-based catalysts were found to support favorable reaction activity as they are cheaper than many exorbitant catalysts. The metal used for catalyst support exhibits higher stability and thermal resistance with improved resistance to coke formation. This review entails recent progresses in the development of Ni-based catalysts along with physical and kinetic aspects of the BRM process.

Today, bi - reforming of methane is considered as an emerging replacement for the generation of high-grade synthesis gas (H2:CO = 2.0), and also as an encouraging renewable energy substitute for fossil fuel resources. For achieving high conversion levels of CH4, H2O, and CO2 in this process, appropriate operation variables such as pressure, temperature and molar feed constitution are prerequisites for the high yield of synthesis gas. One of the biggest stumbling blocks for the methane reforming reaction is the sudden deactivation of catalysts, which is attributed to the sintering and coke formation on active sites. Consequently, it is worthwhile to choose promising catalysts that demonstrate excellent stability, high activity and selectivity during the production of syngas. This review describes the characterisation and synthesis of various catalysts used in the bi-reforming process, such as Ni-based catalysts with MgO, MgO–Al2O3, ZrO2, CeO2, SiO2 as catalytic supports. In summary, the addition of a Ni/SBA-15 catalyst showed greater catalytic reactivity than nickel celites; however, both samples deactivated strongly on stream. Ce-promoted catalysts were more found to more favourable than Ni/MgAl2O4 catalyst alone in the bi-reforming reaction due to their inherent capability of removing amorphous coke from the catalyst surface. Also, Lanthanum promoted catalysts exhibited greater nickel dispersion than Ni/MgAl2O4 catalyst due to enhanced interaction between the metal and support. Furthermore, La2O3 addition was found to improve the selectivity, activity, sintering and coking resistance of Ni implanted within SiO2. Non-noble metal-based carbide catalysts were considered to be active and stable catalysts for bi-reforming reactions. Interestingly, a five-fold increase in the coking resistance of the nickel catalyst with Al2O3 support was observed with incorporation of Cr, La2O3 and Ba for a continuous reaction time of 140 h. Bi-reforming for 200 h with Ni-γAl2O3 catalyst promoted 98.3% conversion of CH4 and CO2 conversion of around 82.4%. Addition of MgO to the Ni catalyst formed stable MgAl2O4 spinel phase at high temperatures and was quite effective in preventing coke formation due to enhancement in the basicity on the surface of catalyst. Additionally, the distribution of perovskite oxides over 20 wt % silicon carbide-modified with aluminium oxide supports promoted catalytic activity. NdCOO3 catalysts were found to be promising candidates for longer bi-reforming operations.

Billingham UK, where Mike Spencer spent his entire industrial career, has long been associated with the use of steam reforming for the production of synthesis gas required for the manufacture of some important chemicals, particularly ammonia and methanol. This paper describes the steam reforming process and presents some of the history of the development of tubular reforming. The catalysts, technology and industrial operation of plants are briefly reviewed. Newer technologies, such as adiabatic reforming, autothermal reforming (ATR) and gas heated reforming (GHR) that aim to increase efficiency of and reduce the environmental impact of conventional steam reforming processes are presented.

It is extremely prudent and highly challenging to design a greener bifunctional electrocatalyst that shows effective electrocatalytic activity and high stability toward electrochemical water splitting. As several hundred tons of catalysts are annually deactivated by deposition of carbon, herein, we came up with a strategy to reutilize spent methane reforming catalysts that were deactivated by the formation of graphitic carbon (GC) and carbon nanofibers (CNF). An electrocatalyst was successfully synthesized by in situ deposition of noble metal-free MoS2 over spent catalysts via a hydrothermal method that showed exceptional performance regarding the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). At 25 mA cm–2, phenomenal OER overpotentials (η25) of 128 and 154 mV and modest HER overpotentials of 186 and 207 mV were achieved for MoS2@CNF and MoS2@GC, respectively. Moreover, OER Tafel slopes of 41 and 71 mV dec–1 and HER Tafel slopes of 99 and 107 mV dec–1 were obtained for MoS2@CNF and MoS2@GC, respectively. Furthermore, the synthesized catalysts exhibited good long-term durability for about 18 h at 100 μA cm–2 with unnoticeable changes in the linear sweep voltammetry (LSV) curve of the HER after 1000 cycles. The carbon on the spent catalyst increased the conductivity, while MoS2 enhanced the electrocatalytic activity; hence, the synergistic effect of both materials resulted in enhanced electrocatalysts for overall water splitting. This work of synthesizing enhanced nanostructured electrocatalysts with minimal usage of inexpensive MoS2 gives a rationale for engineering potent greener electrocatalysts.

Internal dry reforming (IDR) of methane for biogas-fed solid oxide fuel cell (SOFC) applications has been experimentally investigated on planar Ni-GDC (cermet anode) electrolyte-supported cells. This study focuses on the effect of CO2 concentration, current density, operating temperature, and residence time on internal methane dry reforming. A single cell is fed with different CH4/CO2 mixture ratios between 0.6 and 1.5. Extra CO2 recovered from carbon capture plants can be utilized here as a reforming agent. The I-V characterization curves are recorded at different operating conditions in order to determine the best electrochemical performance while the power production is maximized, and carbon deposition is suppressed. The outlet gas from the anode is analyzed by a micro gas chromatograph to investigate methane conversion inside the anode fuel channel and to understand its influence on the cell performance. Relatively long-term experiments have been performed for all gas mixtures at 850°C under a current density of 2000 A m−2. The results indicate that when the cell is fed with biogas with an equimolar amount of CH4 and CO2, carbon deposition is prevented, and maximum power density is obtained.

DMR is a promising technique to utilize the rising greenhouse gases and produce an alternative energy source. The main hurdle in the commercialization of DMR is the catalyst deactivation. Presently, the effect of Tungsten (W) addition on Ni-based catalysts supported on mixed oxide (Al2O3–MgO) support is tested for DMR. The Ni–W bimetallic catalysts are synthesized via co-precipitation followed by the impregnation technique. An equimolar stream of feed (CH4:CO2) is used for DMR at 800 °C. The Ni–W catalyst with 4 wt% of W showed steady performance with elevated conversions of CH4 and CO2, even after 24 h of DMR. The freshly and spent catalysts are characterized by BET, XRD, FESEM, EDX, elemental mapping, TPR-H2, TPD-CO2, and XPS to confirm the elemental composition and the type of carbon formed on the catalysts. The activity of Ni catalyst declined due to formation of amorphous carbon-nanosheets, whereas Ni–W catalyst remained active due to formation of MWCNT.

The review considers the modern structure of methanol production and consumption. The main processes of methanol conversion and the catalysts for their implementation are reported: the production of formaldehyde, hydrocarbons (МТН) and olefins (МТО) as well as the generation of hydrogen from methanol by steam conversion, partial oxidation, autothermal reforming and decomposition.

Conversion of methane into value‐added chemicals is of significance for methane utilization and industrial demand of primary chemical products. The barrier associated with the nonpolar structure of methane and the high bond energy C–H bond (4.57 eV) makes it difficult to realize methane conversion and activation under mild conditions. The photothermal synergetic strategy by combining photon energy and thermo energy provides an advanced philosophy to achieve efficient methane conversion. In this review, we overview the current pioneering studies of photothermal methane indirect conversion and present the methane direct conversion by the way of photocatalysis and thermocatalysis to provide a fundamental understanding of methane activation. Finally, we end this review with a discussion on the remaining challenges and perspectives of methane direct conversion over single‐atom catalysts via photothermal synergetic strategy.

Abstract: Solid Oxide Fuel Cells (SOFCs) is an efficient and clean pathway to generate electricity. In addition to hydrogen, SOFCs also provide the possibility for the utilization of a variety of carbon containing fuels. However, the application of carbon-based fuels in SOFC remains to be further studied. In this study, an external reformer was used to create appropriate reforming syngas from methanol and avoid carbon deposition. The performance and the efficiency of SOFC were researched with methanol-reformed syngas as fuel. The thermodynamic calculation and experimental work of water vapor reforming reaction of methanol fuel were carried out to study the composition of reforming gas under different temperature and steam-carbon ratio conditions, where the experimental results and the computational results matched well. The mole fraction of hydrogen in reformed syngas was about 55% within the temperature of 700~800 ℃, nevertheless, this value reached 70% if the moisture was removed. Therefore, the reformed syngas should be applied to SOFCs before being condensed and dried. Based on the comparison between the experimental results and the calculated ones, the appropriate components were selected to prepare the reforming syngas, feeding into the anode of SOFC to test the performance and the efficiency. Optimal temperature and steam-carbon ratio conditions for methanol vapor reforming were obtained. Under these conditions, the power density of SOFC exceeded 0.4 W/cm2 and the efficiency reached 50% (LHV). The main conclusions confirmed the high efficiency and feasibility of the methanol-fueled SOFC power generation system.

This simulation-based comparative assessment aims to quantify the environmental and human-health impacts of greener hydrogen (H2) production via three glycerol-based technologies, including: supercritical water reforming (SCWR), aqueous-phase reforming (APR) and autothermal reforming (ATR). The GaBi (2018 edition) life-cycle assessment (LCA) platform is used to develop cradle-to-gate product system models for these technologies and the TRACI 2.1 methodology is used to quantify their midpoint impact categories. Aspen HYSYS (v11) process-simulation software is used to generate the life-cycle inventory (LCI) primary data required to produce 1 kg of H2 via each of the indicated glycerol-reforming technologies. Per ISO 14040:2006 reporting requirements for the LCA results interpretation step, three base case (BC) scenarios and four sensitivity scenarios (SS) are developed and quantified to compare the effects of different process electricity sources (US grid mix versus wind power) and thermal energy sources (natural gas versus biogas) on the LCA results. The high operating pressure (viz. 240 bar) of SCWR enabled assessment of the impact of in situ electricity generation to offset some of electricity required for this technology. The major insights from this research are as follows: (i) per 1 kg of produced H2, APR reduces CO2 emissions by ≈95% compared to ATR and by ≈92% compared to SCWR, (ii) for BC scenarios, the primary energy consumption (in MJ/kg of produced H2) is in the following order from highest to lowest: ATR > SCWR > APR and (iii) H2 production via glycerol APR is more environmentally sustainable than SCWR and ATR, and thus offers a promising path for greener H2 production. Future environmental sustainability studies should focus on expanding the scope of this study to include H2 production via water electrolysis using renewable electricity sources and via solar and nuclear-driven thermochemical water splitting.

A thermodynamic study and an energy analysis are performed on the autothermal reforming (ATR) and sorption-enhanced autothermal reforming (SE-ATR) of olive mill wastewater (OMW) to produce green hydrogen. For comparative purposes, the traditional reforming (TR) and sorption-enhanced reforming (SER) are also assessed. The thermodynamic equilibrium compositions are calculated by using the Gibbs free energy minimization method. The effect of temperature, pressure and steam-to-carbon molar ratio (S/C) is assessed for the different reactor configurations. The energy analysis is done by determining the level of oxygen needed to operate under thermally neutral conditions. The results show a reduced hydrogen yield for ATR and SE-ATR compared to their non-autothermal counterparts, but a decreased energy requirement per mole of hydrogen produced. For the ATR, the thermally neutral operation requires a high amount of oxygen, which reduces the hydrogen yield. However, for SE-ATR, the exothermal sorption reaction provides nearly enough energy for the process to be thermally neutral by itself.

The performance of spinel YxCeyRuzO4 (x = 1.5, y = 0.84, and z = 0.04) as the catalyst support in dry and steam reforming of methane (DMR/SMR) in a monolithic microreactor has been investigated. Ni...

This work demonstrated the first-ever cold-start operation of an ammonia (NH3)-fueled four-cylinder spark ignition engine with an on-board fuel reformer, applying autothermal reforming. In this system, an electrically heated NH3-air mixture was provided to a reforming catalyst and approximately 3 s was found to elapse between the start of engine rotation and the onset of combustion. Stable fast idle operation in conjunction with a cold start was realized with a H2-to-NH3 molar ratio of 2:1. Nearly zero NH3 emissions were achieved during cold start and fast idle until the engine warmed up, by adsorbing unburned NH3 passing through a three-way catalyst before the catalyst was sufficiently warmed up. The NH3 adsorption capacity of this system could be regenerated during the engine warm-up when the engine was running under lean conditions.

The commercialization of solid oxide fuel cells (SOFCs) can be significantly promoted with the direct utilization of methane, which is the primary component in natural gas and the second most abundant anthropogenic greenhouse gas. However, carbon deposition on most commonly used Ni-based anode is the bottle-necking issue inhibiting long-term stability of direct methane SOFCs. To avoid such a problem, methane is typically reformed (internally or externally) in SOFCs. Considering the cost, system simplification, coking resistance, and material selection, the on-cell catalytic reforming layer (OCRL) is one of the most promising designs for direct methane SOFCs. Reforming catalytic materials are typically consisted of active component, substrate and catalytic promoter, all of which have a significant impact on the catalytic activity, sintering resistance and coking resistance of methane reforming catalysts. This review summarizes the influence of the various components, some common OCRL materials and their applications in direct methane SOFCs, reforming and coking resistance mechanism, as well as the remaining challenges. The effective utilization of OCRL plays a pivotal role in promoting the development of direct methane SOFCs and the commercialization of SOFCs.

A rapid start-up strategy of a diesel reformer for on-board fuel cell applications was developed by fuel cell integration. With the integration with metal-supported solid oxide fuel cell which has high thermal shock resistance, a simpler and faster start-up protocol of the diesel reformer was obtained compared to that of the independent reformer setup without considering fuel cell integration. A reformer without fuel cell integration showed unstable reactor temperatures during the start-up process, which affects the reforming catalyst durability. By utilizing waste heat from the fuel cell stack, steam required at the diesel autothermal reforming could be stably provided during the start-up process. The developed diesel reformer was thermally sustainable after the initial heat-up process. As a result, the overall start-up time of the reformer after the diesel supply was reduced to 9 min from the diesel supply compared to 22 min without fuel cell integration.

Net Zero has the aim of achieving equality between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. There is widespread acceptance that for Net Zero to be achievable, chemistry, and hence catalysis, must play a major role. Most current studies of catalysts and catalysis employ a combination of physical methods, imaging techniques and spectroscopy to provide insight into the catalyst structure and function. One of the methods used is neutron scattering and this is the focus of this Perspective. Here, we show how neutron methods are being used to study reactions and processes that are directly relevant to achieving Net Zero, such as methane reforming, Fischer–Tropsch synthesis, ammonia and methanol production and utilization, bio-mass upgrading, fuel cells and CO2 capture and exploitation. We conclude by describing some other areas that offer opportunities.

The reforming of methane is an important industrial process, and reactor modeling and simulation is frequently employed as a design and analysis tool in understanding this process. While much research work is devoted to catalyst formulations, reaction mechanisms, and reactor designs, this review aims to summarize the literature concerning the simulation of methane reforming. Applications in industrial practice are highlighted, and the three main approaches to representing the reactions are briefly discussed. An overview of simulation studies focusing on methane reforming is presented. The three central methods for fixed-bed reactor modeling are discussed. Various approaches and modern examples are discussed, presenting their modeling methods and key findings. The overall objective of this paper is to provide a dedicated review of simulation work done for methane reforming and provide a reference for understanding this field and identifying possible new paths.

To make clear the feasibility and influence factors of diesel fuel autothermal reforming to hydrogen, PdCeCr- FeCu/Al2O3 catalyst was prepared by equivalent-volume impregnation method. Experimental facility based on an adiabatic tubular reactor with preheating section was designed and set up, the behaviors of diesel reforming to hydrogen with straight-run diesel as a raw material according to the analysis of the components were studied. Diesel oil reforming over a catalyst for hydrogen production was analyzed using an adiabatic tubular reactor with a preheating section that was designed and built in-house. The operating conditions were optimized. Under the suitable operating conditions, viz., catalyst bed inlet temperature of 700 °C, diesel liquid space velocity of 0.24 h−1, water-carbon ratio of 20, and oxygen-carbon ratio of 0.6, the hydrogen yield reached 28.3 (mol/mol).

The autothermal reforming (ATR) process for hydrogen production saves considerable energy for the reaction compared with endothermic steam methane reforming (SMR). However, it requires a supply of ...

The energy supply systems dependent on fossils and municipal solid waste (MSW) materials are primarily responsible for releasing greenhouse (GHG) gases and their related environmental hazards. The increasing amount of methane (CH4) and carbon dioxide (CO2) is the scientific community's main concern in this context. Reduction in the emission amount of both gases combined with the conversion technologies that would convert these total threat gases (CO2 and CH4) into valuable feedstocks will significantly lower their hazardous impact on climate change. The conversion technique known as dry methane reforming (DMR) utilizes CO2 and CH4 to produce a combustible gas mixture (CO+H2), popularly known as synthesis gas/or syngas. Therefore, this research study aims to explore and enlighten the characteristics of the DMR mechanism. The conversion behaviour of CO2 and CH4 was studied with modelling and simulation of the DMR process using MATLAB. The results showed that inlet gas flow has a significant impact on the reactions. In contrast, the inlet molar composition ratio of the reactions was found to have no substantial effect on the mechanism of DMR. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

This paper reports the usage ratio of TEOS and Zr(OBu)4 on the formation of Ni@ZrO2 yolk-shell for dry reforming of methane. From XPS analysis, the ZrO2 hollow shell texture is demonstrated to be [TEOS]/[Zr(OBu)4] dependent due to different sizes of SiO2 produced. It found that an adequate ratio of [TEOS]/[Zr(OBu)4] improves the catalytic conversion of dry reforming of methane. It (Ni@ZrO2-SiZr-7.7) shows 90% conversion for CH4 and 93% for CO2 at a WHSV of 72,000 mLgcat−1h−1 for 50 h at 800 °C with TOFCH4 of 8.7 s−1. It proposed that the changes in surface Si/Zr and gradual interconnecting pores contributed to its activity and stability. These finding’s potential to be utilized in other high-temperature reactions.

In recent years, there has been growing interest in the dry reforming of methane (using CO2 instead of H2O) to obtain syngas, due to its economic and environmental advantages. In this reaction, to achieve conversions close to 100%, it is necessary to work at temperatures higher than 1000 °C. However, to attenuate the catalyst deactivation by sintering is convenient to work at lower temperatures, so that normally the syngas (mixture CO + H2) is obtained mixed with unreacted CO2 and CH4. In this work a process has been simulated to recover the syngas from the product of a dry reforming reaction of methane at 700 °C by means of a Dual PSA (Dual Pressure Swing Adsorption) process with heavy reflux using BPL activated carbon as an adsorbent, operating at 25 °C. The process can recover syngas with purity and recovery higher than 99%. Unreacted CO2 and CH4 can be recycled to the reactor, leading to effective CO2 and CH4 conversions close to 100%. The process specific energy input (SEI) is 4.7 thermal kJ per L (STP) of syngas. The process can also be used to recover the syngas contained in the tail gas of a H2 purification PSA from SMR-off gas.