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This study examined the impact of varying concentrations of ammonia-borane (AB) in gasoline on engine performance and emissions across different load conditions. Four fuel formulations were tested: pure gasoline (G100) and gasoline blends containing 10%, 15%, and 20% AB (AB10, AB15, AB20). Increased AB concentration resulted in higher brake-specific fuel consumption (BSFC). While exhaust gas temperatures were highest with G100 (730.9 °C at full load), the AB blends, particularly AB20, exhibited lower temperatures, with a maximum reduction of 13.8%. The AB20 blend demonstrated elevated BSFC and increased oxygen (O₂) emissions but significantly reduced carbon monoxide (CO) emissions, with up to an 88.2% decrease at full load. Nitrogen oxide (NO x) emissions were generally lower for all AB blends. The highest NO x value was measured with G100 fuel at full load, while the lowest NO x value was measured with AB10 fuel. Under these conditions, a 23% decrease in NO x value was observed with AB10 fuel compared to G100. The engine's thermal efficiency decreased with AB blends at all load levels compared to pure gasoline. Thermal efficiency decrease of 13.76%, 22.32%, and 30.88% occurred for AB10, AB15 and AB20, respectively compared to G100.Overall, incorporating AB in gasoline reduced thermal efficiency and led to a notable decrease in NO x , hydrocarbons (HC), and CO emissions. [Display omitted] • Alcohol-gasoline blend fuels AB10, AB15 and AB20 were created. • All blended fuels were tested in a single cylinder gasoline engine. • AB blends show higher brake specific fuel consumption (BSFC) values compared to pure gasoline. • AB10, AB15 and AB20 showed lower thermal efficiency compared to G100 at all engine loads. • AB blends reduced harmful emissions such as CO, HC and NOx. [ABSTRACT FROM AUTHOR]

Solid Oxide Fuel Cells (SOFCs) are capable of generating electrical and thermal power with very high conversion efficiency and almost no pollutant emissions into the atmosphere. Despite extensive literature on SOFC-based energy system models and experimental testing at the cell and short-stack level, there is currently a lack of performance data for SOFC modules under actual field conditions. To fill this gap, the present work investigates the energy and environmental performance of six SOFC modules, ranging in size from 10 to 60 kW, over thousands of hours of operation. These systems, supplied by the three leading SOFC manufacturers in Europe, have been installed and operated in different non-residential buildings worldwide, as part of the European Comsos project. The aim of this study is to establish a comprehensive set of field operation data to characterise commercial-scale SOFC systems. Specifically, raw data are processed to derived electrical and thermal efficiency maps, degradation rates and pollutant emissions, including particulate matter (PM), nitrogen oxides (NO x) and carbon monoxide (CO). A comparison with competing technologies is also provided to better highlight the potential benefits of adopting SOFC-based cogeneration systems. Values in the range of 51–61% were found for the system-level electrical efficiency under rated conditions. The electrical efficiency also remained consistently high across a wide modulation range (between 50% and 100% of rated power), with peak values reaching 65%. In addition, promising results were obtained for the average percentage loss in electrical efficiency, with a minimum value of 0.7%/1000 h. Regarding the environmental analysis, NO x and CO emissions were analysed at both constant and variable power output, proving to be impressively low across the entire modulation range. The same applies to PM concentrations, which were below ambient level. Overall, SOFCs demonstrated to be one of the best cogeneration solutions for commercial-scale systems (tens to hundreds of kW in size), from both an energy and environmental perspective. However, further reductions in costs and dedicated financial schemes are necessary for a widespread market penetration. [Display omitted] • Energy and environmental performance from the field operation of six SOFC systems. • Rated AC electrical efficiency of 51%–61%, with stable performance at partial load. • Maximum AC electrical efficiency of up to 65%. • Percentage loss in AC electrical efficiency of 0.7 %/1000 h. • Very low values for NO x and CO emissions, even at partial load. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3), as an ideal zero-carbon fuel, plays a positive role in mitigating global warming. By cofiring NH 3 with highly reactive small molecule fuels such as hydrogen (H 2), carbon monoxide (CO) and methane (CH 4), the reactivity of NH 3 combustion can be significantly enhanced. In this work, a detailed kinetic mechanism for NH 3 /CH 4 /H 2 /CO containing 146 species and 1099 reactions was developed and extensively validated with selected experimental data from the literature on laminar burning velocity (LBV), ignition delay time (IDT), and species concentrations measured in burner-stabilized flames (BSF), plug flow reactors (PFR) and jet-stirred reactors (JSR), covering temperatures of 273–2000 K, pressures of 0.053–40 atm and equivalence ratios of 0.1–2. In addition, the detailed mechanism was simplified to include 53 species and 353 reactions using three simplification methods. Kinetic modeling analysis showed that the chemical and transport effects of H 2 , CO and CH 4 are the main factors enhancing NH 3 combustion, which rising with the increasing initial temperature and decreasing ammonia blending ratio. Among the four reactants, H 2 is consumed first, followed by CH 4 and NH 3 , with CO reacting last. By modifying the Metghalchi-Kech power law equation, it was found that a clear linear relationship exists between LBV and the sum of the maximum mole fractions of O, H, OH, and NH 2 radicals. [Display omitted] • A kinetic mechanism for NH 3 /CH 4 /H 2 /CO was proposed and simplified. • Validation range includes T 0 of 273–2000 K, P 0 of 0.053–40 atm and Ф of 0.1–2. • Chemical kinetics of LBV for NH 3 /H 2 , NH 3 /CO and NH 3 /CH 4 blends were studied. • The correlation between LBV and free radicals was investigated. [ABSTRACT FROM AUTHOR]

Waste Shiitake Substrate, a major agricultural waste in Taiwan, is typically packaged in plastic bags (Waste Polyethylene, PE) during mushroom cultivation process. Consequently, these plastic bags become additional waste that requires proper disposal. In recent years, Taiwan has produced over 150,000 tons of waste shiitake substrate annually, with approximately 1580 tons of plastic bags used for mushroom cultivation. Up to now, there has not been an effective method for handling this waste. This study aims to develop a co-gasification process using the complementary characteristics of WSS and PE. Unlike traditional direct combustion, the co-gasification approach can convert these wastes into cleaner bioenergy. This study aims to develop an Aspen Plus model for a laboratory-scale 1 kW th bubbling fluidized bed gasifier. This model incorporates kinetic reactions and tar formation during co-gasification. The model accurately predicted the experimental results. Different variables were investigated, including gasifier temperature, blending ratio (BR) of the two fuels, mixing ratio (MR) of the gasifying agent, and equivalence ratio (ER). The results showed that hydrogen production correlated positively with the steam-to-carbon ratio in the gasification medium, whereas carbon monoxide (CO) was more affected by the feedstock type and equivalence ratio, with CO reaching its peak at an equivalence ratio of 0.2. When gasifying using only waste shiitake substrate (BR = 0%), at an ER of 0.2, a gasification furnace temperature of 950 °C, and an MR of 100% (pure CO 2), the maximum CO mass flow rate in the syngas is obtained. Waste plastics contain significant amounts of volatile matter and no oxygen, leading to increased production of CH 4 , CO, and H 2 during co-gasification with the addition of waste plastic. For plastics, high temperature and low ER conditions promote the production of CO, H 2 , and CH 4 because of the significant tar content, thereby enhancing the Cold gas efficiency (CGE). When the gasification temperature is 950 °C, with 80% polyethylene (BR = 80%) and an ER of 0.1, the highest HHV is achieved. These results can serve as a reference for determining the operational conditions for the scale-up of gasification systems. • Co-gasification of WSS/PE was studied by Aspen Plus kinetic modeling. • A comprehensive parameter analysis was conducted based on the proposed model. • Maximum CO was obtained when gasifying pure waste shiitake substrate with CO 2. • The optimal conditions for the highest H 2 /CO ratio (1.58) were obtained. • The cold gas efficiency (CGE) value is promoted due to the cracking of tar. [ABSTRACT FROM AUTHOR]

A reverse flow porous medium reactor with premixed and non-premixed flames was experimentally investigated to evaluate the influence of steam and carbon dioxide on methane (CH 4) filtration combustion for syngas production. Premixed, non-premixed, and non-premixed with steam were the tested cases for different injection configurations. Thermal profiles, combustion products, hydrogen (H 2) and carbon monoxide (CO) yields for several equivalence ratios are analyzed. Non-premixed case exposed higher maximum temperatures due to the reactant accumulation at the crosswise injection position, with a temperature of 1615 K. The lack of homogenization of the reactants in this configuration leads to low H 2 and high CO concentrations compared to the premixed case. The maximum CO yield was 92.81% for the non-premixed configuration with alternated air injection, while the maximum H 2 yield was 37.8% for the premixed air-methane-steam case. It was found that the air-methane-carbon dioxide mixtures had lower temperatures, combustion wave velocities, and H 2 and CO concentrations, compared to the air-methane, and air-methane-steam mixtures, but higher CH 4 and CO 2 concentrations. The premixed configuration with air-methane-carbon dioxide mixture showed higher temperatures, and H 2 and CO concentrations, compared to the non-premixed configuration. Further studies are necessary to optimize the operation of these types of reactors. • Methane filtration combustion in a reversal flow porous media reactor. • Steam and carbon dioxide on the methane filtration combustion were investigated. • Thermal profiles, and hydrogen and carbon monoxide production were analyzed. • Premixed flames showed higher H 2 and CO production than non-premixed flames. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of combustion efficiency in a dual-fuel diesel engine powered with oxyhydrogen as the primary fuel and a Graphene oxide nanoparticle-dispersed biodiesel/diesel blend as the pilot fuel. A Box-Behnken design (BBD) is employed to develop an L 17 orthogonal array for three factors and three levels of input parameters: engine load, HHO flow rate, and EGR ratio. An RSM-based 3D surface plot is utilized to analyze the interaction between input parameters and responses. Multi-objective optimization through RSM-based desirability and genetic algorithms (MOGA) is conducted to obtain the optimal engine operating parameters. The MOGA approach demonstrates superior performance compared to the RSM-based desirability approach. The optimal engine operating parameters identified by the MOGA approach are an engine load of 9.89 kg (approximately 3.43 kW), an HHO flow rate of 5.78 L/min, and an exhaust gas recirculation (EGR) ratio of 10.18%. At this optimized operating condition, the performance and combustion output are 31.85% BTE, 0.3268 kg/kWh of BSFC, and 60.16 bar of peak cylinder pressure (PCP). In terms of emissions, carbon monoxide (CO) is 0.04152 vol %, hydrocarbon (HC) is 25.45 ppm, and nitrogen oxide (NO x) is 746.12 ppm. Experimental validation confirms that all results are within an acceptable limit with a maximum error of 6%. Oxyhydrogen significantly enhances fuel efficiency and consumption while simultaneously reducing carbon-based emission levels, except for nitrogen oxide emissions. The adverse effects of an increase in NO x are mitigated by the addition of EGR. [Display omitted] • Biodiesel synthesis using ultrasonic-assisted technology. • Study of dual-fuelled diesel engine behavior with nanoparticles, HHO and EGR. • Application of RSM-based predictive models for performance and emission analysis. • Multi-objective optimization through RSM and GA for engine response optimization. • The optimal engine operating conditions are: load 9.89 kg, HHO flow rate 5.78 L/min, and EGR 10%. [ABSTRACT FROM AUTHOR]

Diesel generators are widely used to produce electricity and heat in remote communities. However, their use contributes to harmful pollutant and greenhouse gas (GHG) emissions, negatively impacting the environment and public health. Syngas, which is a sustainable fuel, can play an important role in the transition from petroleum to renewable fuels. When used in dual-fuel diesel engines, it can contribute to reducing GHG emissions and the cost of transporting diesel, especially for rural and remote communities. This study investigates the effects of optimizing the diesel direct injection (DI) and exhaust gas recirculation (EGR) strategies on the combustion and emission performance of a syngas-diesel dual-fuel generator at constant load. The experiments were conducted using a 30-kW generator with a four-stroke, four-cylinder, turbocharged, and electronically controlled direct-injection diesel engine. The intake manifold of the engine was modified to allow introducing syngas upstream of the turbocharger. The syngas was simulated using individually controlled flow rates of hydrogen (H 2), carbon monoxide (CO), carbon dioxide (CO 2), and nitrogen (N 2). The syngas flow rate was adjusted to replace 40% of the energy provided by diesel fuel while optimizing the diesel DI parameters such as the pilot injection timing, main injection timing and diesel direct injection rail pressure, as well as the EGR rate. The findings of this study reveal that optimizing diesel injection strategy and appropriately raising the EGR rate have a positive impact on the engine performance and emissions. • Optimizing diesel injection strategies and EGR rate of a syngas-diesel dual-fuel diesel engine. • Hydrogen-rich syngas enhances combustion efficiency and emissions control. • Fine-tuning of pilot injection timing and duration improved the engine efficiency and emissions. • Increasing EGR rate stabilized emissions, with notable reductions in NOx and CO levels. • Adjustment of the main injection timing positively impacted combustion characteristics. • Increasing the injection pressure resulted in notable reductions in CO and PM emissions. [ABSTRACT FROM AUTHOR]

The present work utilizes a response surface optimization technique to optimize hydrogen-rich syngas production through the process of methane dry reforming (DRM). This optimization is achieved by employing a bimetallic Mn–Ni/La 2 O 3 catalyst. The study aimed to evaluate the impact of three key parameters, namely reaction temperature, time on stream (TOS), and gas hourly space velocity (GHSV), on the hydrogen to carbon monoxide (H 2 /CO) ratio in syngas during the DRM. The Mn–Ni/La 2 O 3 catalyst, synthesized using the sequential wet impregnation technique, exhibited suitable physicochemical properties necessary for DRM reaction, as evidenced by the obtained characterization data. Among the five models examined, it was found that the quadratic versus 2FI model substantially fit the experimental data, as evidenced by a p-value <0.05. The analysis of variance (ANOVA) conducted on the quadratic response surface model compared to the 2FI model demonstrated that both the reaction temperature and the TOS had a significant impact on the H 2 /CO ratio in the syngas. The only significant interaction factor was the relationship between the reaction temperature and the TOS. Under the specified optimal circumstances of 15 000 ml/g.h, 850 °C, and 258.15 min, an H 2 /CO ratio of 0.98 was achieved. The resulting H 2 /CO ratio of 0.98 is almost 1, indicating its suitability as a feedstock for methanol production in the Fischer-Tropsch synthesis (FTS). • The Mn–Ni/La 2 O 3 catalyst exhibited suitable properties necessary for DRM reaction. • Temperature and time had a substantial impact on the H 2 /CO ratio in the syngas. • The response surface quadratic model is statistically significant to fit the experimental data. • At optimized conditions H 2 /CO ratio of 0.98 was obtained for the syngas. [ABSTRACT FROM AUTHOR]

Chemical looping dry reforming of methane (CLDRM) offers a sustainable pathway to convert methane (CH 4) and carbon dioxide (CO 2) to syngas, i.e., a mixture of hydrogen (H 2) and carbon monoxide (CO). However, carbon deposition caused by high gas temperature remains a crucial challenge for the CLDRM. We proposed microwave (MW) heating-assisted CLDRM to leverage the selective heating feature of MWs to create a thermal gradient between solid and gas phases. This thermal gradient, i.e., a higher solid temperature than the gas temperature, can promote desired reduction and oxidation (redox) reactions, while suppressing undesired gas phase reactions, in particular, CH 4 decomposition. At bulk temperature of 800 °C, the MW heating-assisted CLDRM achieved a maximum CH 4 conversion of 97% and H 2 /CO ratio of around 2. Compared to the conventionally heated CLDRM, the MW heating increased the redox extents of magnetite (the oxygen carrier) by 2.5 and 1.5 times, respectively, and suppressed carbon deposition. [Display omitted] • A new chemical looping dry reforming of methane adopting microwave heating. • Magnetite as a good microwave absorber and oxygen carrier. • Increasing methane conversion, hydrogen selectivity, and reduction extent of magnetite. • Mitigating carbon deposition on the magnetite oxygen carrier. [ABSTRACT FROM AUTHOR]

Proton exchange membrane (PEM) fuel cells require high-purity hydrogen. Carbon monoxide (CO) is a common impurity in hydrogen that significantly reduces the performance of PEM fuel cells. Currently, there are two main methods to eliminate the effect of CO: direct removal of CO and increasing the CO tolerance of PEM fuel cells. Each method has its advantages and disadvantages. It is important to consider the specific application when choosing between these methods. This review summarizes the mechanism of CO poisoning and its effect on the operation and durability of PEM fuel cells, as well as hydrogen purification and CO-tolerant techniques. Then analyzes the advantages and disadvantages of commonly used techniques and predicts future research directions for PEM fuel cells using impure hydrogen containing CO, aiming to expand the application scenarios, and promote the large-scale application of PEM fuel cells. • Mechanisms of CO poisoning on PEM fuel cells are summarized. • Impacts on potential oscillation and durability are reviewed. • Various hydrogen purifications techniques are compared. • CO-tolerant techniques for PEM fuel cells are discussed. • Futher directions for research on eliminating CO effect are presented. [ABSTRACT FROM AUTHOR]

The production of hydrogen-rich gas used in fuel cell-powered cars from steam reforming and sorption-enhanced steam reforming of ethanol was studied over nickel-impregnated mesoporous carbon catalyst in conventional and microwave heated reactor systems. Two important process intensification methods, sorption-enhanced reforming and microwave heating, were investigated to obtain a sustainable and energy-efficient system. Higher hydrogen yield was observed in the microwave heated system compared to the conventional heated system. With an increase in the reaction temperature, the hydrogen yield and hence the hydrogen concentration were increased in both systems. Sorption-enhanced steam reforming resulted in very high hydrogen purity, higher than 97 %, containing no carbon monoxide and carbon dioxide before the breakthrough point in the microwave system at 500 °C. The outperformance of the microwave system compared to the conventional system was proved in terms of the hydrogen yield and purity. • Nickel impregnated mesoporous carbon catalyst has a high microwave absorption capacity in the microwave system. • Higher hydrogen yield and purity were achieved in the microwave system. • Sorption-enhanced results revealed very high H 2 purity in the MW reactor at 500 °C during the first 25 min of the reaction. • The enhancement in hydrogen yield and purity in the MW system are evidence of its superiority to the conventional system. [ABSTRACT FROM AUTHOR]

The accurate measurement of the thermal conductivity of hydrogen is crucial in efficiently integrating hydrogen into diverse applications that encompass storage, utilization, and production. This paper introduces strong intelligent algorithms capable of predicting the thermal conductivity of hydrogen-based binary gaseous mixtures consisting of carbon monoxide (CO), methane (CH 4), and carbon dioxide (CO 2), based on the mole fractions of these components, pressure, and temperature. To this end, four advanced intelligent models, namely Radial Basis Function (RBF), Cascade Forward Neural Network (CFNN), Multilayer Perceptron (MLP), and Generalized Regression Neural Network (GRNN) were developed. After that, an analysis of graphical and statistical errors was conducted to further examine the precision of the proposed models. The findings revealed a strong alignment between the suggested models and experimental values. Additionally, among the developed models, the GRNN technique was identified as the superior forecasting approach with the (RMSE = 0.00129) and the highest value of the coefficient of determination, (R2 = 0.9987). Moreover, the sensitivity analysis of the GRNN model indicates that hydrogen composition has the highest influence on the thermal conductivity of hydrogen-based gaseous mixtures, as evidenced by the relevancy factor value of 0.881. The assessment of group errors also demonstrates that the proposed models exhibit high accuracy when confronted with higher temperatures and pressures. Ultimately, the Leverage analysis was employed to evaluate the dependability of the new paradigm, revealing that more than 97% of the data falls within the applicable range of the paradigm. • Intelligent approaches estimate the thermal conductivity of H2-based mixtures. • GRNN technique outperforms other models for forecasting thermal conductivity. • Hydrogen composition has the highest influence on thermal conductivity. • Proposed models exhibit high accuracy at higher temperatures and pressures. [ABSTRACT FROM AUTHOR]

This study experimentally and numerically determined the effect of CO 2 on H 2 /air explosion. The results indicated that CO 2 can effectively reduce the maximum explosion pressure, the maximum explosion pressure rise rate and flame propagation speed of hydrogen explosion. Numerical simulations have confirmed that adiabatic flame temperature, laminar burning velocity, free radical concentration and the rate of product gradually decrease of hydrogen explosion with the increase of CO 2 concentration. Among them, the changing trend of H radicals and laminar burning velocity is most closely related. Further analysis of the formation of H radicals found that as the CO 2 concentration increases, reaction R31:CO + OH CO 2 +H(ΔH = -203.5 kJ/mol) gradually proceeds in the reverse direction. While removing H radicals, the system temperature is absorbed, but a certain amount of CO is produced. In addition, analysis found that the physical inhibition effect of CO 2 is significantly greater than the chemical inhibition effect. When φ = 0.6, physical inhibition effect accounts for 77 % of the total inhibition effect, and chemical inhibition effect accounts for 23 % of the total inhibition effect. When φ > 0.8, as the equivalence ratio and CO 2 concentration increase, the proportion of physical inhibition effects gradually increases, and the proportion of chemical inhibition effects gradually decreases. The reason for the increase in the proportion of physical inhibition is that the dilution effect gradually shifts from promotion to inhibition. • The physical endothermic effect is the most important inhibitory effect of CO 2. • The dilution effect has a dual effect of promoting and inhibiting the hydrogen laminar flame speed. • CO 2 has inhibitory effect on different equivalence ratios of hydrogen. • CO 2 suppresses hydrogen explosions to produce higher concentrations of CO. [ABSTRACT FROM AUTHOR]

A particle-resolved model is implemented to investigate the performance of porous catalyst during the methane bi-reforming process, where the reaction and diffusion inside the catalyst particle are considered. The difference of specific surface area between pore structures is also taken into consideration. The performance of monodisperse and bi-disperse catalysts is evaluated. The results reveal that the bi-reforming process depends on the competition and coordination between dry reforming reaction and steam reforming reaction. The pore size doses not monotonously influence the ratio of hydrogen to carbon monoxide production. For the bi-disperse pore catalyst, owing to the synergistic effect of diffusion and reaction, there exists an optimal macropore fraction of 0.5 for hydrogen generation rate. There is an optimal macro-pore size of about 10 μ m to achieve a stable hydrogen production rate. • Particle-resolved simulation is conducted for bi-reforming process of catalyst. • Dependence of catalyst behaviors on pore structure parameter is evaluated. • There exists an optimal macro-pore fraction of 0.5–0.7 for hydrogen production. [ABSTRACT FROM AUTHOR]

In the present study, pine (Pinus brutia) and poplar (Populus alba) tree barks, softwood and hardwood representative biomass were evaluated for production of gas biofuel, hydrogen by aqueous-phase reforming. The proximate composition, elemental composition, higher heating values (HHVs), proximate thermogravimetric and differential thermogravimetric analysis (TGA/DTG), fourier transform infrared (FT-IR), and volatile composition of these biomass materials were determined and their effect on gasification performance of the softwood and hardwood biomass were evaluated. Gasification was performed by aqueous-phase reforming of solubilized liquid fraction of the biomass materials in presence of carbon-supported Pd catalyst which was synthesized in the present study. Softwood contained significantly higher levels of ash and volatile matter, with lower hemicellulose but higher lignin content. Gasification results showed that softwood produced slightly higher amounts of hydrogen with significantly lower carbon monoxide compared to hardwood. Although solid hardwood bark composition was expected to produce more gaseous products, the results observed were opposite. The dissolution of biomass in pressured hot water prior to gasification resulted in a more dilute hydrolysate in softwood compared to hardwood, positively influencing the gasification performance. Despite of many advantages of the aqueous-phase reforming (APR) gasification process used in the present study, the process still needs to be improved further to make the process more economical. To increase the advantage of this process, new catalysts that are more robust and active and have high stability in organic-rich APR conditions should be developed. [Display omitted] • Softwood and hardwood barks were evaluated for production of fuel. • Hardwood barks dissolved more easily in pressured hot water than softwood. • Gasification results showed that softwood produced slightly higher hydrogen. [ABSTRACT FROM AUTHOR]

In this work, the laminar premixed flames for methane and propane at atmospheric pressure were numerically investigated with respect to different hydrogen concentrations, ranging from 5 % to 25 % (by vol.). Based on the two-dimensional (2D) flame predictions, hydrogen decreased the maximum temperatures and species concentrations such as formaldehyde (CH 2 O), acetylene (C 2 H 2), carbon monoxide (CO) and nitric oxide (NO) for methane and propane. However, the CH 2 O mole fractions were raised by a maximum deviation of 10 % when hydrogen was added into the fuel lean and stoichiometric propane mixtures. The decrease in C 2 H 2 eventually lowered the soot volume fractions and number densities. Besides, the axial locations of the maximum species concentrations, soot volume fractions and number densities were also affected by hydrogen. Meanwhile, the addition of hydrogen increased the flame temperatures and laminar burning velocities for the one-dimensional (1D) premixed flames of methane and propane. This trend was identically predicted for the formation of intermediate species such as CH 2 O, hydroperoxyl (HO 2) and hydroxyl (OH) whereas C 2 H 2 , CO and NO were lowered, as justified by the sensitivity analyses. For propane at an equivalence ratio (φ) = 1.3, the rates of production (ROPs) of C 2 H 2 were increased linearly with hydrogen, which resulted in higher C 2 H 2 concentrations. • Methane and propane coflow flames with hydrogen addition are modelled in 1D and 2D. • Hydrogen lowers flame temperatures, CH 2 O, C 2 H 2 , CO and NO for 2D flames. • For 1D flames, hydrogen raises flame temperatures and intermediate species. • Effects of hydrogen on emissions depend on fuel types and mixture conditions. [ABSTRACT FROM AUTHOR]

The utilization of clean and renewable fuels has become increasingly significant in the power generation and transportation sectors. Dual-fuel engines that employ hydrogen and algal biodiesel are potential alternatives. This study investigated the impact of pilot fuel injection pressures and engine loads on the performance and emissions of an algal biodiesel-hydrogen dual-fuel engine. The engine was optimized using response surface methodology under various operating conditions. The highest brake thermal efficiency (28.71 %) was obtained at 240 bar pilot fuel injection pressure and 100 % engine load, significantly reducing carbon monoxide and hydrocarbon emissions. The optimum parameters were identified using response surface methodology at 67.63 % engine load and 245.48 bar pilot fuel injection pressure, with a high model fit (R2) range of 88.89 %–99.59 % and composite desirability of 96.1 %. The potential for optimizing algal biodiesel-hydrogen dual-fuel engines to achieve greater efficiency and environmental benefits is highlighted in this work, as is the relevance of applying response surface methods to optimize engine performance. • Algae Biodiesel-Hydrogen dual fuel resulted 28.11 % highest brake thermal efficiency. • Algae Biodiesel-Hydrogen dual fuel resulted less emissions than biodiesel alone. • Response surface model achieved strong data fitting between 91 and 99 %. • Optimal response surface found at 62 % load and 246.75 bar pilot injection pressure. • 96 % composite desirability achieved using response surface optimization. [ABSTRACT FROM AUTHOR]

The thermodynamic simulation analysis of carbon monoxide water gas shift in rich hydrogen was researched by using the method of Gibbs free energy minimization with Aspen plus software. For the purpose of purifying trace amount of CO in hydrogen, two raw gas compositions, 1%CO–99%H 2 and 1%CO–24%CO 2 –75%H 2 , were purposely selected, and the influences of water to gas molar ratio (1–7) and transformation temperature (40–280 °C) were investigated. The results showed similar variation law as compared with the water gas shift of a pure CO gas. When the transformation temperature increased, the chemical equilibrium shifted toward the reverse direction, resulting in decreased CO equilibrium conversion; when the water to gas molar ratio increased, the CO conversion increased. The results also showed that CO 2 had great negative effects on CO conversion compared with H 2. For the CO/H 2 feed gas, it was concluded that it was possible to reduce the 1% CO content to 100 ppm at 120 °C with the use of the best low-temperature catalyst reported in literature. If we want to further reduce the trace amount of CO in hydrogen to 10 ppm, it is necessary to develop ultra-low temperature catalysts that are highly active below 70 °C. • Simulation of CO water gas shift reaction in excess H 2 and H 2 /CO 2. • CO 2 has a great influence on CO conversion compared to H 2. • 1%CO in H 2 reduced to 100 ppm with the available catalyst at 120 °C. • To reduce CO to 10 ppm, it is necessary to develop catalysts below 70 °C. [ABSTRACT FROM AUTHOR]

Methane (CH 4) is the second most abundant greenhouse gas (GHG) after carbon dioxide (CO 2) and is widely recognized as one of the most destructive GHGs, exerting negative impacts on the Earth's atmosphere. In order to effectively reduce CH 4 emissions, the conversion of methane into synthesis gas, which is a mixture of hydrogen (H 2) and carbon monoxide (CO), has emerged as an appealing approach. Recent advancements have demonstrated that catalytic partial oxidation of methane (POM) holds great promise as a reaction pathway for syngas production. Here we study a series of catalysts consisting of monometallic Ru and Ni, and bimetallic Ru–Ni supported on CeO 2. These catalysts were synthesized using both mechanochemical and conventional incipient wetness impregnation methods. Various preparation parameters were investigated, including the Ru:Ni metal ratio, the order of metal addition, and the milling energy and time for the mechanochemically prepared samples. The catalysts were subjected to low-temperature POM (350–600 °C) experiments to evaluate their performance. The experimental results reveal that the bimetallic Ru–Ni/CeO 2 catalysts exhibit superior catalytic activity and stability compared to the monometallic Ru–CeO 2 and Ni–CeO 2 catalysts. Notably, the bimetallic Ru–Ni/CeO 2 catalysts prepared through ball milling demonstrate a significantly lower temperature requirement for syngas production compared to the conventional catalysts prepared via incipient wetness impregnation. [Display omitted] • Monometallic Ru and Ni and bimetallic Ru–Ni on CeO 2 for partial oxidation of CH 4. • Mechanochemical and conventional incipient wetness impregnation methods. • Ru–Ni/CeO 2 prepared by ball milling more active at low temperature and stable. • Ball-milled Ru–Ni/CeO 2 with stronger interaction between Ru, Ni and CeO 2. [ABSTRACT FROM AUTHOR]

Electric arc furnace dust (EAFD) recycling is based on the reduction of oxides containing iron and zinc. With regard to the sustainability of industrial processes, hydrogen reduction processes could be the key technology to replace current recycling technologies based on carbothermal reduction. In this context, hydrogen is often claimed to provide better reduction kinetics, but it is mostly unclear how much faster it is. The present work gives a comprehensive comparison of the reduction kinetics of the major zinc- and iron-containing oxides in EAFD (Fe 2 O 3 , ZnOFe 2 O 3 , and ZnO) using hydrogen and carbon monoxide under various process parameters. The influence of specimen size, reduction gas flow rate, and temperature were evaluated. The kinetic advantage of hydrogen compared to carbon monoxide was confirmed, enabling the reduction of direct CO 2 -emission. Hydrogen results in a 2.5 times faster reduction of Fe 2 O 3 and a doubling of the reduction rate for ZnOFe 2 O 3. ZnO reduction was determined to be 1.5 faster. Furthermore, ZnO was found to be the rate-limiting substance in the recycling of EAFD, regardless of the reducing agent. • The kinetical advantage of H 2 compared to CO is the most pronounced for Fe 2 O 3 and decreases for ZnOFe 2 O 3 and ZnO. • The temperature dependency for both reducing agent is only visible for ZnO. for the entire experiment. • Within the applied temperature (800–900 °C) both reducing agents only show a marginal temperature dependency for Fe 2 O 3. • Fe 2 O 3 reduction was found to be controlled by diffusion and ZnO reduction was found to be controlled by chemical reaction. • Doubling of gas flow leads to a doubled reduction rate. Quadrupling of the gas flow results in a tripled reduction rate. [ABSTRACT FROM AUTHOR]

This work applies computer simulation to investigate the combined approach of hydrogen (H 2) addition with lean operation to enhance the potential of ethanol as a clean engine fuel for low-carbon transportation. To this end, this research evaluates how this operation regime impacts brake power, fuel conversion efficiency, and exhaust emissions. A dedicated software was used to perform a parametric study with varying amount of hydrogen addition and excess air ratio. The software combustion and performance parameters were calibrated against available experimental data and optimised for engine operation at the tested conditions. The results show that hydrogen addition does not produce noticeable effects on brake power and fuel conversion efficiency for lean operation with up to 20% air excess. However, for operation with 40% air excess, 6% H 2 addition is necessary to keep the power at the same level of the engine baseline condition while simultaneously improving fuel conversion efficiency. Operation in the range of air excess between 10% and 30% together with hydrogen addition up to 2% can simultaneously produce noticeable improvements of fuel conversion efficiency, carbon monoxide (CO) and hydrocarbon (HC) emissions, without compromising brake power and oxides of nitrogen (NO X) emissions. • Engine performance is reproduced or improved up to 20% air excess, 6% hydrogen. • Operation with 40% air excess requires 6% hydrogen to ensure adequate performance. • Up to 2% hydrogen and 20% air excess improves fuel conversion and carbon emissions. • Oxides of nitrogen emissions unaffected with up to 2% hydrogen and 20% air excess. • 6% hydrogen with 40% excess air also provides benefits to efficiency and emissions. [ABSTRACT FROM AUTHOR]

Syngas produced by catalytic partial oxidation (CPOX) of propane contains hydrogen (21.68%) and carbon monoxide (18.27%). Microtubular solid fuel cells (μT-SOFCs) were fabricated and tested with syngas and pure hydrogen respectively. The open-circuit voltage (OCV) is 1.02 V, and the maximum power (MP) of microtubular solid fuel cell is 7.07 W at 700 °C with syngas/air. After operating in syngas/air for 100 h, the voltage declined 4.5%. A few sites of anode separate from electrolyte, particularly, some few nanometers nickel (Ni) particles have precipitated at the interface of electrolyte/anode. Comparing to Ni grain with 200 nm-1 μm diameter in rest sites of anode, it is easy to explain the loss of Ni and the separation of anode with electrolyte. Meantime obvious carbon deposition is found at the pores after 100 h working in syngas/air. There are other impurity phases discovered by high resolution transmission electron microscopy (HRTEM) at a triple phase boundary (TPB) of electrolyte and anode. • Nano-domains of nickel are expelled as clusters from anode into amorphous oxidized phase. • The loss of nickel causes to the difference of nickel grain size. • The structure of anode is destroyed by the growth of carbon at 700 °C. • The triple phase boundary degenerates towards the double phase boundary for long-term working. [ABSTRACT FROM AUTHOR]

China's annual metallurgical by-product gas production exceeds 1400 billion Nm3, the calorific equivalent of ∼266 million tonnes of coal. The widely-studied blast furnace gas used in hydrogen-enriched carbonic oxide recycling oxygenate furnaces ensures carbon-reduction. Converter gas contains abundant heat resources, equivalent to ∼6.5 million tonnes of coal. Using high-temperature by-product gas online reforming methods to convert thermal energy into chemical energy and combining it with power generation and other industries imparts physical heat recovery exceeding 60%. China's annual coke oven gas (COG) production could support more than 100 million tonnes of direct reduced iron production, thus reducing CO 2 emissions by more than 150 million tonnes (nearly 10% of China's steel industry CO 2 emissions). We summarise the characteristics, availability, and steel-chemical co-production utilisation of three by-product gases, and discuss the application of COG in direct reduced iron production and development of metallurgical by-product gas utilisation for carbon reduction in China. • Development direction of metallurgical by-product gas. • The utilisation of by-product gas in steel-chemical co-production. • Coke oven gas for direct reduction ironmaking. • Online reforming method to convert thermal energy into chemical energy. • Blast furnace gas for hydrogen-enriched carbonic oxide recycling oxygenate furnace. [ABSTRACT FROM AUTHOR]

The water gas shift reaction is one of the most important reactions in ammonia production plants for purifying hydrogen streams from carbon monoxide. This reaction occurs in two consecutive reactors at high and low temperatures. In the current study, the simulation was first carried out for these two reactors in one of the ammonia production units, and then the process variables were optimized to maximize hydrogen production in three states: one that was relatively near-equilibrium, one that was far from equilibrium and one that was near the end of the run. Methanol formation as a byproduct was also identified during process evaluation as a crucial limitation. The optimization results in all three modes indicate that maximum carbon monoxide conversion could be achieved during the catalyst lifetime if the reactors operate at low temperature and pressure at the start-up. As the catalyst lifetime increases, the inlet temperature and pressure must be increased to keep the catalyst active. [Display omitted] • The Water Gas Shift process in Ammonia plant was simulated using Aspen plus software. • A sensitivity analysis was performed to determine effective operational parameters. • The production of methanol as a by-product was controlled by variation of parameters. • The Water Gas Shift process was optimized to maximize CO conversion. • The optimal steam-to-gas ratio, pressure, temperature profile and GHSV were suggested. [ABSTRACT FROM AUTHOR]

A two-stage hydrogen purification process based on pressure swing adsorption (PSA) and CO selective methanation (CO-SMET) is proposed to meet the stringent requirements of H 2 -rich fuel for kW-scale skid-mounted or distributed proton exchange membrane fuel cell systems. The reforming gas is purified using dynamic adsorption model of PSA with activated carbon for initial purification and then kinetic model of CO-SMET with 50 wt% Ni/Al 2 O 3 for CO deep removal. Sensitive analyses of the gas hourly space velocity, adsorption time and adsorption pressure etc. are studied. The results show that excellent H 2 purity and CO concentration below 1000 ppm for the initial target using the three-bed and four-bed PSA system at shorter adsorption time and higher pressure, and then CO concentration below 10 ppm with H 2 purity over 99.94% on CO-SMET. This work provides a small-scale and hydrogen-saving process for hydrogen purification can be achieved by the two-stage process. The schematic of PSA/CO-SMET two-stage CO deep removal process. [Display omitted] • Two-stage H 2 purification process for kW-scale skid-mounted/distributed PEMFC. • Validation of the two-stage concept by simulation on an exemplary kW-scale system. • Three-bed system with better performance of H 2 purification than two and four beds. • Preferential CO selective methanation at lower temperature and higher pressure. • Pressure matching of pressure swing adsorption with CO selective methanation. [ABSTRACT FROM AUTHOR]

Carbon monoxide selective methanation (CO-SMET) is one of the most efficient technologies for hydrogen purification and CO deep removal. This paper applies the field synergy principle for a deep understanding on the chemically reactive flow in a CO-SMET tubular reactor. The variation of CO conversion rate under different operating conditions is interpreted, at the first time, as relevant to the variation of the synergy angle between temperature and gas concentration fields. Sensitive analyses of the bed pressure, CO/CO 2 ratio, heat exchange modes, etc., are studied to obtain the profile of field synergy angle in the inlet gas temperature range of 373 K – 873 K. It is found that the region with synergy angles between 0° and 70° enhances the heat transfer between mass transfer and contributes the main output of CO conversion. This work provides a fundamental basis on the future optimal design of CO–SMET reactors. [Display omitted] • Field synergy principle with CO selective methanation reaction. • Simulation of CO selective methanation by kinetic equation and CFD. • Synergy angle distribution influence on heat and mass transfer. • Uniform explanation of change of CO conversion rate by field synergy principle. [ABSTRACT FROM AUTHOR]

The CuMn samples with various CuO weight percentages were synthesized by the mechanochemical route. The catalytic activity of the prepared samples was determined in the preferential oxidation of CO process (CO-PROX) in the temperature range of 40–250 °C. According to the XRD results, the 5CuMn and 10CuMn samples exhibited the spinel phase in their structures. The spinel phase formation enhanced the CO adsorption active sites and modified the redox properties. The results indicated that the copper incorporation into the manganese oxide modified the catalytic activity and structural properties. The 5CuMn catalyst with the highest BET area (72.1 m2 g−1) possessed 96% CO conversion and 50% CO 2 selectivity at 70 °C (GHSV = 30,000 ml/h.g cat) and significant resistance in the presence of water due to the formation of hydroxyl groups over the catalyst surface. The catalyst activity remained stable for 14 h at 130 °C. Furthermore, the influence of calcination temperature, feed composition, and GHSV value on the catalytic performance of the 5CuMn catalyst was studied. • The Cu–Mn catalyst with 5 wt% Cu exhibited a CO conversion higher than 90% at 70 °C. • 5 wt%. CuO-MnOx showed a Cu 1.5 Mn 1.5 O 4 spinel structure. • 5 wt%. CuO-MnOx catalyst exhibited sufficient stability in the presence of water vapor. [ABSTRACT FROM AUTHOR]

A cyclic adsorption and plasma-desorption (CAPD) process is applied to remove ppm-level carbon monoxide (CO) from the H 2 -rich stream for the first time. In the CAPD process, CO is first selectively adsorbed on CuCl/γ-Al 2 O 3 till adsorption saturation; Then, the adsorbed CO is in-situ desorbed by plasma generated in dielectric barrier discharge (DBD) and the adsorbent is regenerated simultaneously. The effects of discharge power (P dis) and flow rate of discharge gas (F D) on performances of plasma-desorption are investigated. The time to reach desorption of 50% (t 50) and 90% (t 90) significantly decreases with P dis but is weakly correlated to the F D. At the investigated conditions, t 50 and t 90 are lower than 2.6 min and 4.5 min, respectively, which indicates that plasma-desorption features high desorption rate. In addition, desorption efficiency of plasma-desorption is higher than 98%. Moreover, CAPD process stability is preliminarily confirmed by six consecutive adsorption-desorption cycles. [Display omitted] • A CAPD process to remove ppm-level CO for on-board H 2 production of PEMFC is reported. • The adsorbed CO can be in-situ, fast and efficiently desorbed by plasma. • Time-dependent CO desorption curve accords with discharge characteristics variation. • The stability of CAPD process is preliminarily confirmed. [ABSTRACT FROM AUTHOR]

The removal of CO from hydrocarbon- and methanol-derived hydrogen can be performed by a series of methods to achieve the 10 ppm CO limit required for proton exchange membrane fuel cell (PEMFC) applications. The fuel processing includes reforming of the feed followed by water-gas shift (WGS) and a final CO removal with the latter decreasing the CO concentration below the desirable level. Pressure swing adsorption (PSA), membrane separation, selective methanation (SMET) and preferntial oxidation (PROX) are the applicable techniques as the final clean-up step. The appropriate method depends on the scale but for small scale portable fuel processors, catalytic processes are more appropriate due to the operating conditions close to that of PEMFC. The PROX appears to be the best due to rapid reaction rate and mild operation conditions which renders intensification of the processes possible. Extensive research and development efforts are underway to increase catalyst activity and improve the temperature window of the reaction. [Display omitted] • Small to medium scale fuel processors are needed to produce H 2 for PEM fuel cells. • Following water-gas shift, catalytic CO clean-up is preferred for scale down. • Novel encapsulated and single-atom catalyst concepts enhance CO preferential oxidation. • Non-noble metal catalysts with wide temperature window and stability are investigated. • Both throughput and heat/mass transfer can be enhanced by using monolithic catalysts. [ABSTRACT FROM AUTHOR]

The main aim of this study is to investigate the high-temperature electrochemical hydrogen purification (HT-ECHP) performances of graphene nanoplatelet (GNP) support material decorated with platinum (Pt) and platinum-ruthenium (PtRu) nanoparticles prepared by microwave irradiation technique. Prepared catalysts coupled to the phosphoric acid doped polybenzimidazole (PBI) membrane for HT-ECHP application. The structural and electrochemical properties of the catalysts were examined by thermogravimetric analysis (TGA), X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transition electron microscopy (TEM) and cyclic voltammetry (CV) analyses. The characterization results indicate that the catalysts provided the necessary properties for HT-ECHP application. The HT-ECHP performances are investigated with reformate gas mixture containing hydrogen (H 2), carbon dioxide (CO 2) and carbon monoxide (CO) in the range of 140–180 °C. The results show that the electrochemical purification performances of the catalysts increase with increasing operating temperature. The highest H 2 purification performance is obtained with PtRu/GNP catalyst. The high electrochemical H 2 purification performance of the PtRu/GNP catalyst can be attributed to the strong synergistic interactions between Pt and Ru particles decorated on the GNP. These results advocate that the PtRu/GNP catalyst is a hopeful catalyst for HT-ECHP application. • Pt/GNP and PtRu/GNP catalysts were prepared by microwave irradiation. • Electrochemical H 2 purification was investigated with HT-ECHP system. • Bimetallic PtRu/GNP catalyst exhibited a high ECHC purification performance. [ABSTRACT FROM AUTHOR]

Global reaction mechanisms (GRMs) are widely used in combustion engineering. However, it is difficult to find GRMs commonly available for various mixtures of H 2 , CO, and CH 4 (with air), which are likely to be the primary fuels in the future. In this study, a series of GRMs were optimized to follow the results of the five detailed reaction mechanisms (GRI 3.0, USC II, San Diego, FFCM-1, CRECK) for the essential fuels (H 2 , CO, CH 4) and their mixtures (at 300 K and 1 bar). At first, a 1-step GRM of H 2 +air (R1) and another of CO + air (R2), were optimized to reproduce their respective laminar burning velocities (LBVs). After that, an additional water-gas shift reaction (R3) was suggested to improve the prediction for the H 2 +CO + air mixture. Similarly, a 1-step GRM (M1) was developed for the fuel-lean mixtures of CH 4 +air, and a 2-step GRM (R1+M1) was proposed for the fuel-lean mixtures of H 2 +CH 4 +air. In the case of the mixture of H 2 +CO + CH 4 +air, an additional methane oxidation reaction (M1L) producing H 2 and CO was suggested, and a 4-step GRM (R1+R2+R3+M1L) showed reliable results in the fuel-lean conditions. However, to get reliable LBVs over all equivalence ratios, two additional reactions (M2+M3) were proposed to reflect the endothermic reaction. Furthermore, the pre-exponential factor of the methane oxidation reaction (M1R) varied as a function of the hydrogen concentration in the fuel. Conclusively, acceptable LBVs could be obtained for the H 2 +CO + CH 4 +air mixtures in a moderate temperature range (300 K–600 K). • Global reaction mechanisms (GRMs) were determined for H 2 +CO + CH 4 +air mixtures. • Laminar burning velocities from the detailed reaction mechanisms were compared. • 1-step GRMs were improved for the individual fuels H 2 , CO, and CH 4. • Additional multi-step GRMs were proposed for fuels of various compositions. • Optimized GRMs were proposed for various mixtures of H 2 +CO + CH 4 +air. [ABSTRACT FROM AUTHOR]

To elucidate the coupling effects of temperature and ratio of steam to carbon on the methane steam reforming process, the characterizations of methane steam reforming at different temperature and ratio of steam to carbon in term of distribution of H 2 and CO, and the elementary reaction rate were investigated. Meanwhile, the formation mechanisms of H 2 and CO via sensitivity analysis and reaction path analysis were obtained. The results showed that the coupling effects of temperature and ratio of steam to carbon on the methane steam reforming were higher than that of individual factor. The effects of temperature on the methane steam reforming were higher than that of the ratio of steam to carbon. The adsorption and desorption reaction of CH 4 on the surface of Ni-based catalyst had the most obvious effect on the sensitivity of H 2 , CH 4 and CO. Besides, the effects of adsorption and desorption reaction of H 2 O on the sensitivity of H 2 were higher than that of CH 4 and CO. Hydrogen was generated by the desorption reaction of H(s) in the adsorbed state and from three generating paths: a) CH 4 (s) dissociated directly or reacted with O(s) to form H(s); b) The dissociation reaction of H 2 O(s) produced H(s); c) OH(s) dissociated directly or reacted with C(s) to form H(s). Carbon monoxide was generated from single path: CH 4 (s)→CH 3 (s)→CH 2 (s)→CH(s)→C(s)→CO(s)→CO(g). • The coupling effects of temperature and the ratio of steam to carbon on methane steam reforming mechanism were investigated. • The hydrogen and carbon monoxide reaction path route was obtained. • The methane conducted a direct decomposition reaction on the surface of catalyst which showed as following: CH 4 (s)→CH 3 (s)→CH 2 (s)→CH(s)→C(s). [ABSTRACT FROM AUTHOR]

The current research work focus on the utilization of hydrogen as a fuel in CI engine has been increased tremendously, since it is a zero-emission fuel. But higher self-ignition temperature than conventional fuel, makes to operate in dual fuel mode condition in CI engine. The diesel or biodiesel along with hydrogen in a CI engine results in the improvement in the performance but increase of NO. In order to minimize the NO emission, addition of ethanol with jamun B20 biodiesel blend (biodiesel-diesel-ethanol) and two ternary blends such as B20E05 and B20E10 are formed. In the present study, biodiesel along with H 2 is admitted in the CI engine. Ethanol addition reduces combustion temperature and act as cetane improver for the biodiesel. This induces better combustion of the fuel and reduce NO. The biodiesel production from jamun seed is carried out through transesterification process. H 2 of 4 lpm is allowed at the air inlet and jamun B20 blend is injected through the fuel injector. Improvement of brake thermal efficiency and increase in the NO are observed for the hydrogen with biodiesel operated CI engine. The performance and emission behaviors of CI engine done for the test samples. At full load condition (ternary blend) B20E05 assisted H 2 shows the drastic reduction of NO emission of 8.2% than B20 assist H 2 blend. In other hand emission like hydrocarbon, carbon monoxide and smoke opacity show a notable reduction for B20E05 blend assist H 2 than other test sample fuel. The thermal efficiency is 30.98% for B20E05 assist H 2 and it is 7.55% and 4.7% higher than B20 and B20E05 assist H 2 blend respectively. [Display omitted] • Ternary blends with hydrogen shows higher BTE. • Ternary blends of B20E05 shows 7.7% reduction of NO than B20 aided H 2. • B20E05 aided H 2 has higher heat release rate of 87/°CA. [ABSTRACT FROM AUTHOR]

The syngas production from hydrocarbons by porous media combustion (or conventional gasification) processes has been intensively and extensively studied due its calorific value and its applications in the energy sector. However, the syngas produced in a first stage gasifier can still have concentrations of light hydrocarbons (e.g., methane) which can be post-processing for further enrichment of hydrogen and carbon monoxide. The present work numerically investigates the performance of a second stage porous media burner to enrich the syngas content, mainly hydrogen and carbon monoxide. A one-dimensional model based on a two-temperature approximation is implemented, based on the PREMIX code, and supported by CHEMKIN and GRI-MECH 3.0 database and routines. From hybrid porous bed reactor experiments, five types of mixtures in the equivalence ratio range between 0.4 and 2.4 are tested: pure methane as baseline, pure Eucalyptus nitens syngas, pure Pinus radiata syngas, and two mixtures of methane with each of the biomass syngas in equal volume quantities, as transition points. The results obtained show that in the enriched syngas, in comparison to the first content after the first stage reactor, the concentrations of hydrogen and carbon monoxide increase, due to the partial oxidation of methane, however part of the hydrogen is consumed in the process. The intermediate species present in methane processing for pure syngas mixtures have broader reaction zones and in lower concentrations compared to the use of pure methane. For equivalence ratios greater than 1.9, pure syngas mixtures show higher conversion efficiencies compared to the baseline. At the equivalence ratio of 2.4, the pure syngas from Eucalyptus nitens and Pinus radiata has an energy return over energy invested (EROI) of 58.27% and 53.95%, respectively, and a maximum hydrogen and carbon monoxide yields of 31.66% and 48.40%, respectively. In the case of the Pinus radiata, the outlet syngas concentrations of the hydrogen and carbon monoxide on dry basis expose an increment about two times in comparison to the initial concentrations. [Display omitted] • A second stage porous media burner was used to enrich the syngas content. • Model based on the PREMIX and supported by CHEMKIN was implemented. • The enriched syngas increases hydrogen and carbon monoxide concentrations. • Higher conversion efficiencies were obtained for equivalence ratio greater than 1.9. [ABSTRACT FROM AUTHOR]

Graphene-based catalysts are important in various applications ranging from hydrogen production to fuel cells and gas conversion reactions, due to their high surface area, low density, great mechanical properties, and rich electron density. Carbon monoxide oxidation (CO) is among the hottest research themes, due to its significant role in fundamental industrial, and environmental remediation applications. Graphene-based catalysts are highly promising for CO oxidation, due to their accessible surface area, low-cost, and ease of preparation. However, to the best of our knowledge, there are no review papers on graphene-based catalysts for CO oxidation. Therefore, it is important to provide a timely update on this area of research. This review provides a brief synopsis of the relevant milestones and highlights of graphene-based catalysts for experimental and theoretical CO oxidation reaction. This includes self-standing, doped, and metal nanoparticles supported graphene rooting from the preparation methods to the thermal CO oxidation and their related parameters and mechanisms. The CO oxidation reaction fundamentals (i.e., measurements, calculations, and mechanisms) and the effects of CO on the environment are also highlighted. Finally, the current challenges and drawbacks are discussed for further deployment of novel graphene-based catalysts for efficient CO oxidation under ambient conditions. [Display omitted] • Fundamental, mechanism, and education pathway of catalytic CO oxidation. • Fabrication of graphene doped with non-metal or metal atoms for CO oxidation. • Synthesis of graphene functionalized with non-metal or metal atoms for CO oxidation. • Emphasizing the role of graphene as a support or promoter during the CO oxidation. • The current challenges and outlook of graphene-based catalysts for CO oxidation. [ABSTRACT FROM AUTHOR]

The effect of fuel composition such as hard coal and biomass in fluidized bed on the thermodynamic efficiency of three gasifier types, low heating value (LHV) and syngas composition was studied by simulation in CFD program. The paper presents various small gasification systems with fluidized bed of water-coal mixture and water-biomass mixture both with oxygen (air) and without oxygen. The work presents the extended mathematical model of gasification process taking into account also 13 kinetic chemical reactions enabled to apply them in CFD program. The chemical model is based on surface reactions given in the model of Equivalent Reactor Network (ERN) in Ansys Energetico. Simulation of gasification of different reactor designs enabled to obtain the mass concentration of chemical compounds in the syngas which influenced on thermodynamic efficiency and LHV. Additionally, heating of the gasifier walls by electrical system without air gives higher mass ratio of hydrogen (15%) and carbon monoxide (75%) in the syngas than in the oxidized gasification system. The simulation tests showed high thermodynamic efficiency, taking into account the exergy above 80%, both for the oxygen gasification of hard coal-slurry and biomass as well as for the externally heated gasifier without the supply of oxygen. The highest thermodynamic efficiency 90.5% was obtained during gasification of energy willow in the oxidation reactor due to the large difference in LHV of syngas and fuel. Obtaining the maximum possible mass ratio of H 2 in syngas and a high thermal efficiency for the OXGR system from the gasification of subbituminous coal dust occurs at a ratio C/O 2 = 0.314 and at almost stoichiometric ratio of C/H 2 O = 0.63. In the case of gasification of biomass in the form of finely ground energy willow in the OXGR system, these ratios were respectively: O 2 /C = 1.82 and C/H 2 O = 0.47. While maintaining the almost stoichiometric ratio C/H 2 O = 0.75, resulting from the water-gas shift reaction, low heating value of the syngas for the analysed gasification systems was over 25 MJ/kg. The paper shows comparison of mass fractions of CO, H 2 , H 2 O, H 2 S, CO 2 , O 2 , CH 4 , tar and other chemical compounds in the syngas. Application of the gasification reactor with external heated walls and without oxygen inflow produces the syngas without tar and volatile species in comparison to the systems with additional oxygen supply. In oxidized reactors the syngas contains a large amount of CO 2 about 25–30% of total mass. [Display omitted] • Determination of thermodynamic efficiency in dependence of C/H 2 O and O 2 /C mass ratios. • High mass ratio of hydrogen in the syngas at stoichiometric ratio of C and H2O according to "water-gas shift reaction". • Complex mathematical and chemical model of gasification reactions. • CFD determination of syngas chemical composition for gasification systems. • High caloric value in the syngas from external and internal heated gasifiers also for biomass. [ABSTRACT FROM AUTHOR]

Biogas, landfill gas, associated petroleum gas, and other tail gases accompanying various industrial processes are potential sources of hydrogen and carbon monoxide for solid oxide fuel cells via the reforming process. As these gases contain heavy hydrocarbons, fine-tuning of steam and carbon dioxide addition and specific temperature control are necessary to avoid carbon deposition during the reforming process. Numerical simulation plays a crucial role in designing miniaturized steam reforming reactors and optimal working conditions. All simulations of reforming processes must account for carbon deposition. The methods commonly seen in the open literature include Gibbs free energy minimization or parametric equations formalism. This paper utilizes Gaussian process regression as a tool for making predictions about which reforming parameters are suitable for carrying out this process without the danger of damaging the catalyst due to a carbon formation. Parametric equations formalism and Gibbs free energy minimization involve either the minimization of objective function or a search for roots of nonlinear functions. These tasks are sensitive to a choice of the starting points of the algorithm — wrong choice of starting points could lead to numerical instability. Unlike conventional methods, the Gaussian process regression approach bypasses the computation of equilibrium composition. It predicts carbon formation tendencies directly from the initial conditions which ensure stability. • Carbon deposition is a problem during reforming of biogas and APG. • Gaussian process regression (GPR) used to find carbon-free regime. • Accuracy of GPR method is above 99%. • Comparing to common solutions, GPR method is reliably faster, which makes it a good candidate to use in CFD simulations. [ABSTRACT FROM AUTHOR]

Chemical looping hydrogen production is a kind of technology for high-carbon energy cleaning and low-carbon utilization with great development potential, which can realize H 2 production and CO 2 separation at low cost. CaSO 4 oxygen carrier, as the non-metal oxide oxygen carrier, is not only cheap in price and friendly to the environment, but also high in amount of oxygen carried and excellent in the thermodynamic reaction property. For the key problem of its popularization and application – low reaction rate, this paper investigated the diffusion transport characteristics of the fuel gas molecule, which was one of key microprocesses affecting the reaction rate, in the channel of CaSO 4 oxygen carrier. Based on the channel of CaSO 4 oxygen carrier and the slit model, the influence of the slit width, reaction temperature and coverage rate of doped element Na or Fe of oxygen carrier on the internal diffusion behavior of CaSO 4 oxygen carrier was investigated by the molecular dynamics simulation. The results show: CO molecules physical adsorb on CaSO 4 slit surface; Increase of the slit width will reduce the binding of CaSO 4 surface on single CO molecule, but CO molecular diffusion capacity will increase first and then decrease; The temperature rises will result in the growth of CO molecular diffusion capacity, because CO molecule to be easy to diffuse to the unoccupied reaction site; After Na and Fe is loaded on CaSO 4 slit surface, CO molecular diffusion capacity is greatly improved, and the diffusion coefficients of CO molecule are 27 and 28 times of pure CaSO 4 slit surface, respectively. The calculation results can provide theoretical basis for the structural design and channel optimization of calcium-based oxygen carrier for chemical looping hydrogen production. [Display omitted] • Diffusion transport characteristics of CO within CaSO 4 slit has been studied. • CO diffusion capacity increases first and then decrease with slit width increasing. • Na and Fe loaded on CaSO 4 improves CO molecular diffusion capacity greatly. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) poisoning of polymer electrolyte membrane fuel cells (PEMFCs) remains a challenge for their deployment, and a deeper understanding of the spatiotemporal dynamics involved is needed to develop effective mitigation strategies. In this work, localised reference electrodes were used to measure the anode overpotential at three locations across the active area of a galvanostatically operated cell (0.3 A cm−2) exposed to 100 ppm CO/H 2. The anode region closest to the inlet was poisoned more rapidly than the rest of the cell, following a sigmoidal variation, and presented a higher CO coverage. The varying CO concentration, combined with local operating conditions, had a direct impact on the distribution of CO coverage. Additionally, complex self-sustained oscillations of the cell voltage and the anode overpotential were observed and correlated with the rate of CO oxidation in the overall cell. The coexistence of a dominant mean-field coupling area closer to the anode inlet, and a dominant migration coupling region closer to the outlet was identified, consistent with reported modelling predictions for a single straight channel cell. Finally, the cell recovery with pure H 2 was shown to be a faster process than the CO adsorption, which follows first-order kinetics and is affected by local conditions. • In situ measurements of anode overpotential performed in the presence of CO. • Local operating conditions had an impact on distribution of adsorbed CO. • Spatiotemporal dynamics observed, including self-sustained potential oscillations. • Coexistence of dominant mean-field and migration coupling areas identified. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations have been carried out to investigate the hydrogen and carbon monoxide adsorption characteristics of cationic lithiated carbene complexes. Through the computation of electron density and electron−density−based reactivity descriptors, the nature of interactions related to the bonding between carbene and lithium as well as that between lithium and adsorbed H 2 and CO are examined. Calculations reveal that the carbene−Li + complexes can absorb a maximum of four H 2 molecules reaching a maximum gravimetric density of 8.8 wt%, whereas, it is found to reach a maximum of 41.3 wt% for the absorption of four CO molecules. The fate of H 2 absorption in a carbene−Li+ complex has been studied in the course of a 2000 fs time evolution through Born−Oppenheimer Molecular Dynamics simulation at different temperatures. The outcomes reveal that the H 2 molecules are strongly bound at 77 K and get slowly released at elevated temperature. Carbene−Li+ complexes were found to have potential H 2 and CO adsorption abilities. [Display omitted] • Li doped N -heterocyclic carbenes absorb a maximum of four H 2 and CO molecules. • The complexes show significant gravimetric adsorption density. • The studied complexes show reversibility behaviour for H 2 adsorption. • H 2 molecules are strongly bound at low temperature; desorbs at higher temperature. • CO molecules stay strongly bound at higher temperature. [ABSTRACT FROM AUTHOR]

Hydrogen is a renewable gas, efficient to produce energy that makes it a suitable alternative and effective solution for a carbon-free environment. Unlike other fossil fuels, combustion of hydrogen does not produce toxic compounds, such as greenhouse gases, carbon monoxide, hydrocarbons, etc., resulting in less environmental pollution. Agro-industrial residues contain several lignocelluloses that favor the growth of microorganisms to produce valuable products such as hydrogen. Of the diverse techniques in hydrogen production, bioconversion proves to be an efficient method in permuting agro-industrial residues into hydrogen. This review provides detailed information on the bioconversion processes and factors involved in hydrogen production from agro-industrial residues including different fermentation processes such as dark fermentation and photo-fermentation, and fuel cell systems such as microbial electrolysis cell and microbial fuel cell. Different pretreatment techniques to enhance the availability of lignocellulose for hydrogen production have been elaborated in this review. Various factors including pH, temperature and nutrient composition of feed, affecting the production efficiency and purity of the products during fermentation have been discussed. [Display omitted] • Agro-industrial residues are suitable feedstock for hydrogen production. • Difficulties and future perspectives of biohydrogen conversion are discussed. • Coupling of dark fermentation with MEC increases net energy gain. • Integration of MEC and MFC shows potential over conventional techniques. [ABSTRACT FROM AUTHOR]

Previously, we reported that the hyperthermophilic archaeon, Thermococcus onnurineus NA1 could produce hydrogen from various resources including carbon monoxide (CO) with high productivity. In this study, a high-performance and cost-effective fermentation process was developed as a prerequisite for the industrial implementation of H 2 production from CO using the strain. Firstly, an economical medium was formulated on the basis of natural seawater. Cysteine as a reducing agent was found to be an important factor to consider. Secondly, three variables, initial concentration of yeast extract, CO supply rate and agitation rate, were statistically optimized in batch culture by applying a response surface methodology. Notably, biomass productivity of 0.39 g/L/h could be observed and cell density reached 14 optical units at 600 nm, which is exceptionally high among members of the order Thermococcales. Finally, continuous cultures were tested at various dilution rates with new medium formulation and optimized culture conditions. As a result, the steady state of H 2 production and cell growth were stably maintained, yielding H 2 production rate of 471.5 mmol/L/h at a dilution rate of 0.1 h−1, which is one of the highest values at ambient CO pressure to date. Our study shows that T. onnurineus NA1 has outstanding potential as an economical and high performance industrial strain suitable for long-term processes for CO-dependent H 2 production. • Natural seawater medium for gas (CO) fermentation of the hyperthermophilic archaeon, Thermococcus onnurineus NA1 was formulated. • Gas fermentation variables on the medium formulation were statistically optimized in batch culture by applying a response surface methodology. • Steady state of H 2 production and cell growth were stably maintained with H 2 production rate of 471.5 mmol/L/h, which is one of the highest values at ambient CO pressure to date. • Biomass productivity and cell density were exceptionally high among members of the order Thermococcales. [ABSTRACT FROM AUTHOR]

Oxy-hydrogen gas (HHO) is a carbon-free fuel, which is produced by the water electrolysis process. It can be used as an alternative to hydrogen since the current global hydrogen production and storage may not meet the required demand for transportation applications. This research work investigates the engine behavior of a compression ignition (CI) engine operated in dual-fuel mode by inducting HHO as a primary fuel and injecting two different pilot fuels viz., diesel, and JME20 (a blend composed of 80% diesel with 20% Jatropha methyl ester) at optimized engine conditions. The results revealed that; heat release rate, brake thermal efficiency, exhaust gas temperature, and nitric oxide emission are found to be higher about 5.2%, 1.1%, 18.6%, and 19.6% respectively, while unburnt hydrocarbon, carbon monoxide, and smoke emissions are reduced by about 33.3%, 29.4%, and 18.7% respectively in Opt.JME20 + HHO operation compared to that of the baseline data at maximum load. [Display omitted] • A CI engine is powered by Oxy-hydrogen gas (HHO) in dual-fuel mode. • The higher energy share of HHO is observed at higher loads in dual-fuel mode. • A maximum heat release rate is noticed with HHO induction in dual-fuel mode. • The Opt.JME20 + HHO operation reduces the CO emissions by about 33%. • The induction of HHO with JME20 reduces the smoke emissions by about 18.7%. [ABSTRACT FROM AUTHOR]

The catalytic reforming is an applicable method to generate hydrogen as an alliterative fuel directly that is of prime interest to replace hydrocarbon fuels. Although, the use of this type of catalyst has the potential to solve the problem of safe storage of hydrogen in ICEs, but, this method suffers from the simultaneous production of carbon monoxide with hydrogen known as syngas. Depending on the engine operating conditions, different syngas composition in terms of H2/CO volumetric ratio can be produced through the mentioned catalyst. An engine performance which uses onboard hydrogen produced is completely affected by syngas composition. Therefore, the aim of the current simulation study is to evaluate the performance of a heavy-duty diesel engine under RCCI combustion fueled with diesel fuel/natural gas blended with syngas with different compositions. For this purpose, at 9.4 bar gross IMEP, natural gas is gradually replaced by five different compositions of syngas that is H2/CO volumetric ratios of 33.33/66.67, 50/50, 66.67/33.33, 80/20, and 100/0. The simulation results show that not only the engine output power can be improved up to 27.7% by simply increasing of the CO/H2 volumetric ratio in syngas composition to 66.67/33.33, but also the GIE is reduced by less than 9%. In contrast, the risk of the diesel knock occurrence may increase only in higher CO/H2 ratios. Although, the NOx level can be achieved closer to the EURO VI level, but, same level for UHC and CO and also the level of EPA 2007 for formaldehyde are not achievable for syngas with the higher CO/H2 volumetric ratio. [Display omitted] • The use of onboard hydrogen produced through a catalytic fuel reformer. • Reduction in fuel consumption over 60%. • Gross indicated efficiency reduction about 9%. • Engine power enhancement up to 28%. • Increasing the potential of NOx reduction to EURO VI. [ABSTRACT FROM AUTHOR]

In order to reduce greenhouse gas emissions and ensure the transition to hydrogen economy, the development of new carbon-neutral technologies is required. One of the possible technologies is the detonation decomposition of acetylene with the simultaneous production of hydrogen and carbon black with a minimal emission of carbon monoxide. Acetylene for this purpose can be obtained by various methods, including plasma conversion of methane without CO 2 emission. This paper presents the results of experiments on the production of hydrogen and carbon black in the form of Nanoscale Detonation Carbon (NDC) on a laboratory version of the Pulse Gas-Detonation Device. This apparatus can produce 1.7 kg of hydrogen and 17.7 kg of NDC per hour. • Acetylene as an intermediate product between methane and hydrogen. • Detonation of fuel-rich acetylene-oxygen mixtures. • Detonation excitation at atmospheric pressure. • Hydrogen obtained together with carbon black. • Carbon footprint reduction. [ABSTRACT FROM AUTHOR]

In this experimental study, the conversion of waste glycerol, derived from industrial biodiesel production process, to syngas in water vapor DC thermal arc plasma was carried out. Pure water vapor was used as a gasifying agent, a heat carrier and a plasma-forming gas. This enabled to avoid undesirable ballast products, such as nitrogen oxide, and obtain higher hydrogen and carbon monoxide concentration. It was found that a higher process efficiency (the concentration of H 2 57.9 vol% and CO 21 vol%, the H 2 /CO ratio 2.76, the yield of H 2 70 mol.% and CO 37 mol.%, the tar content 0.822 g/m3, the carbon conversion efficiency 68%, the energy conversion efficiency 39.5%) with a lower specific energy requirement (227.8 kJ/mol) was obtained at the highest H 2 O/C 3 H 8 O 3 ratio of 1.9 (or water vapor flow rate of 14.76 kg/h, waste glycerol content of 7.88 kg/h, and the plasma torch power of 57 kW). This study is expected to provide an effective and advanced waste-to-energy solution. • Waste glycerol gasification in pure water vapor thermal plasma. • Main reaction products H 2 (57.87 vol%) and CO (21 vol%), the H 2 /CO ratio 2–2.76. • At optimal experimental conditions the yield of H2 - 70 mol.% and CO - 25.38 mol.%. • The highest value of ECE - 39.53%, the lowest SER - 227.8 kJ/mol (or 2.11 kWh/kg). • Tar content in the syngas 0.366–0.822 g/m3. [ABSTRACT FROM AUTHOR]

This work introduces CeZr 0.5 GdO 4 spinel particles as novel oxygen carriers for use in the reforming and decomposition of methane into H 2 and CO via the chemical looping technique. These particles were prepared by a modified sol-gel combustion method to increase their reactivity by increasing the surface area and consequently more accessibility of the gas feed to the solid phase. The performance of the synthesized materials was dynamically evaluated in terms of activity and stability at different operating temperatures (800–900 °C). The air used in the oxidation step eliminates almost all of the deposited solid carbon and converts it to CO, while providing the oxygen consumed in the reduction step. Oxygen carrier particles showed a conversion of more than 90% in all cycles after about 30 min of reduction operations. By the optimal operating path proposed in this research, more than 90% of the reactor exhaust gas is allocated to the production of H 2 and CO with almost complete elimination of CO 2 and H 2 O in a shorter period of time. This will also reduce the time required for coke gasification and lattice oxygen replenishment of the spinel. Finally, the CeZr 0.5 GdO 4 proved to be a successful oxygen carrier for the continuous production of hydrogen and carbon monoxide with almost no remarkable reduction in activity during successive redox cycles. [Display omitted] • Chemical looping reforming (CLR) of methane has been investigated. • CeZr 0.5 GdO 4 spinel was synthesized as a new oxygen carrier for CLR process. • High-purity H 2 production was experimentally obtained using successive redox cycles. • Solid carbon can be well eliminated by gasification reactions occurred in the process. • Optimal operating conditions were proposed for maximum production of H 2 and CO. [ABSTRACT FROM AUTHOR]

This study aims at producing hydroxy (HHO) gas using a dry cell electrolysis setup and utilising it along with orange oil in a diesel engine. First an electrolyser was designed considering the optimised values of the material (SS316L), electrolyte (NaOH), and electrode gap (2 mm). Then the biodiesel obtained from the waste orange peels, after transesterification, were blended with diesel at 25 and 50% by vol. The HHO gas was produced by the water electrolysis method by a plate-type electrolyser having a maximum production rate of 2.5 LPM with NaOH as the electrolyte. HHO gas was inducted through the inlet manifold along with the fresh air at a constant rate of 2 LPM with both the biodiesel blends. The performance, emission, and combustion outcomes of the single cylinder diesel engine for different load conditions (0–100%) were tested for all the blends with and without HHO addition. The results showed a considerable increase in brake thermal efficiency of 1.54% at full load condition, with a noticeable decrease in fuel consumption by 11.1% compared to conventional diesel fuel, was achieved for the O25 blend with HHO induction. Moreover, emissions like hydrocarbon, carbon monoxide and smoke were reduced by 17.6, 29.5, and 12.1%, respectively. However, the improvement in combustion outcomes led to the increase in nitrogen oxides emission by 9.67%. This study helped to understand the production process of HHO gas by dry cell electrolyser and its effect on the blend of orange oil methyl ester and diesel in dual-fuel mode. [Display omitted] • Optimisation process showed that SS316L, with NaOH electrolyte and 2 mm electrode gap had the best HHO gas production. • Dual fuel process of using diesel and orange oil blends along with HHO gas provided better engine outcomes. • 25% of biodiesel with 2 LPM of HHO improved efficiency by 9.08%. • Emissions such as HC, CO and Smoke were reduced by 17.6, 29.5 and 12.01%. • 9.67% of NOx increase was also noticed. [ABSTRACT FROM AUTHOR]

15 wt.%Ni-12.5 wt.%Co–Al 2 O 3 catalysts promoted with Fe, Mn, Cu, Zr, La, Ce, and Ba were prepared by a novel solid-state synthesis method and employed in CO 2 methanation reaction. BET, XRD, EDS, SEM, TPR, TGA, and FTIR analyses were conducted to identify the chemicophysical characteristics of the prepared samples. The addition of Fe, Mn, La, Ce, and Ba was effective to improve the catalytic performance of the 15 wt%Ni-12.5 wt%Co–Al 2 O 3 due to the higher CO 2 adsorption capacity of the promoted catalysts. Among the studied promoters, the Fe-promoted catalyst possessed the highest catalytic activity (X CO2 = 61.2% and S CH4 = 98.87% at 300 °C). Also, the effect of calcination temperature, feed composition, and GHSV on the performance of the 15 wt%Ni-12.5 wt%Co-5wt%Fe–Al 2 O 3 catalyst in CO 2 methanation reaction was assessed. The outcomes confirmed that the 15 wt%Ni-12.5 wt%Co-5wt%Fe–Al 2 O 3 catalyst with the BET area of 122.4 m2/g and the highest pore volume and largest pore diameter had the highest catalytic activity. Also, the catalytic performance in the methanation of carbon monoxide was studied, and 100% conversion of carbon monoxide was observed at 250 °C. [Display omitted] • Catalytic hydrogenation of CO 2 to CH 4 was studied over Ni based catalysts. • Mechanochemical synthesis method was used for the catalyst synthesis. • The addition of Fe improved the reducibility and dispersion of nickel species. • The 15Ni-12.5Co–5Fe–Al 2 O 3 catalyst showed high activity and stability. • The highest CO 2 conversion was achieved at low reaction temperature of 350 °C. [ABSTRACT FROM AUTHOR]

The paper aims to investigate the steam reforming of biogas in an industrial-scale reformer for hydrogen production. A non-isothermal one dimensional reactor model has been constituted by using mass, momentum and energy balances. The model equations have been solved using MATLAB software. The developed model has been validated with the available modeling studies on industrial steam reforming of methane as well as with the those on lab-scale steam reforming of biogas. It demonstrates excellent agreement with them. Effect of change in biogas compositions on the performance of industrial steam reformer has been investigated in terms of methane conversion, yields of hydrogen and carbon monoxide, product gas compositions, reactor temperature and total pressure. For this, compositions of biogas (CH 4 /CO 2 = 40/60 to 80/20), S/C ratio, reformer feed temperature and heat flux have been varied. Preferable feed conditions to the reformer are total molar feed rate of 21 kmol/h, steam to methane ratio of 4.0, temperature of 973 K and pressure of 25 bar. Under these conditions, industrial reformer fed with biogas, provides methane conversion (93.08–85.65%) and hydrogen yield (1.02–2.28), that are close to thermodynamic equilibrium condition. • A model for an industrial reformer for steam reforming of biogas (SRB) developed. • Preferable process feed conditions are P = 25 bar, T = 973 K, S/C = 4 and heat flux = 65 kW/m2. • An existing industrial reformer for steam reforming of methane can be used for SRB. • Performance of industrial reformer is close to that achieved at equilibrium. • The study provides the guidelines for industrial steam reforming of biogas (SRB). [ABSTRACT FROM AUTHOR]