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Diesel reforming is a promising hydrogen production technology used for the clean energy conversion of high-carbon-content fuels. Although the reaction system has been established, predicting the optimal reaction conditions for the system remains challenging. Here, we obtained a set of 675 data points from Aspen Plus simulations and trained regression models to predict the reaction condition ranges that yield the highest hydrogen production in diesel reforming. The ETR model achieved the best predictive performance, with an R2 value of 0.99. Interpretable machine learning methods revealed that temperature is a crucial feature determining the baseline hydrogen yield of the diesel reforming reaction, while the steam-to-carbon ratio is key to enhancing hydrogen yield. Our exploratory study underscores the ability of data-driven ML models to uncover the condition-yield relationship in catalytic diesel reforming for hydrogen production by isolating the effects of individual design parameters, a feat that is difficult to achieve through experimental means. [Display omitted] • Research methods combining Aspen Plus simulation and machine learning. • Interpretable machine learning models with deep analytical capabilities. • Obtain guidance intervals for reaction conditions that can be directly used. • Machine learning with minimal prediction and experimental errors. [ABSTRACT FROM AUTHOR]

Dry reforming with CO 2 is one potential method for tar removal and further production of syngas in biomass gasification, but the crucial catalysts with good reaction characteristics are still being developed. In the work, Ni/pyrochlore was proposed to be utilized as catalysts in the dry reforming of tar, and thermodynamic calculation, reaction progress test, and materials characterization were conducted to reveal dry reforming characteristics over Ni/pyrochlore catalysts and the reaction mechanism behind. Results show that YS 0.2 C catalyst exhibits the best activity (toluene and CO 2 conversion of 70.1% and 79.5%) and stability among all catalysts under the optimized conditions of 700 °C with a CO 2 /toluene molar ratio of 7. Analysis on physicochemical properties of the catalysts indicate Sr doping can effectively promote catalytic reforming by enhanced interaction between Ni and support, CO 2 adsorption and oxygen mobility. The work offers a promising catalyst type in improving tar removal by dry reforming. • Systematic study on pyrochlore supported Ni catalysts in the dry reforming of tar. • Ni/Y 1.8 Sr 0.2 Ce 2 O 7 exhibits superior activity and stability during dry reforming. • Reaction conditions were optimized to be at 700 °C with CO 2 /toluene = 7. • Sr doping contributes to the interaction, CO 2 adsorption and oxygen mobility. [ABSTRACT FROM AUTHOR]

Steam reforming is an effective method for improving heat sinks of hypersonic aircraft at high flight Mach numbers. However, unlike the industrial process of producing hydrogen with a high water content, the catalytic steam reforming mechanism for the regeneration cooling process of hydrocarbon fuels with a water content below 30% is still unclear. Catalytic steam reforming (CSR) and catalytic thermal cracking (CTC) reactions occur at low temperatures, with the main products being hydrogen and carbon oxides. Thermal cracking (TC) reactions occur at high temperatures, with the main products being alkanes and alkenes. The above reaction exists simultaneously in the regeneration cooling channel, which is referred to as partial catalytic steam reforming (PCSR). Based on the experimental measurement results, an improved neural network correction method was used to establish a four-step global reaction model for the PCSR of n-decane under low water conditions. The reliability of the four-step model was verified by combining the model with a numerical simulation program and comparing it with the experimental results obtained by electric heating hydrocarbon fuels with a pressure of 3 MPa and a water content of 5/10/15%. The experimental and predicted results using the developed kinetic model are consistent with an error of less than 5% in the decane conversion rate. The average absolute error between the fuel outlet temperature and total heat sink is less than 10%. Using the PCSR model to predict the heat transfer characteristics of mixed fuels with different water contents, the convective heat transfer coefficient is basically the same, and the Nu number is affected by the thermal conductivity coefficient, showing different patterns with changes in the water content. [ABSTRACT FROM AUTHOR]

• Waste coffee pods (CP) were treated using a two-stage pyrolysis process. • A microwave-assisted pyrolysis process was employed for treating waste CP. • Catalytic reforming of evolved gas yielded 76 % (by volume) hydrogen at 900 °C. • Microwave and catalysis-assisted pyrolysis process can be a solution to upcycling. Plastic waste poses a critical environmental challenge for the world. The proliferation of waste plastic coffee pods exacerbates this issue. Traditional disposal methods such as incineration and landfills are environmentally unfriendly, necessitating the exploration of alternative management strategies. One promising avenue is the pyrolysis in-line reforming process, which converts plastic waste into hydrogen. However, traditional pyrolysis methods are costly due to inefficiencies and heat losses. To address this, for the first time, our study investigates the use of microwave to enhance the pyrolysis process. We explored microwave pyrolysis for polypropylene (PP), high-density polypropylene (HDPE), and waste coffee pods, with the latter primarily comprising polypropylene. Additionally, catalytic ex-situ pyrolysis of coffee pod pyrolysis over a nickel-based catalyst was investigated to convert the evolved gas into hydrogen. The single-stage microwave pyrolysis results revealed the highest gas yield at 500 °C for HDPE, and 41 % and 58 % (by mass) for waste coffee pods and polypropylene at 700 °C, respectively. Polypropylene exhibited the highest gaseous yield, suggesting its readiness for pyrolytic degradation. Waste coffee pods uniquely produced carbon dioxide and carbon monoxide gases because of the oxygen present in their structure. Catalytic reforming of evolved gas from waste coffee pods using a 5 % nickel loaded activated carbon catalyst, yielded 76 % (by volume) hydrogen at 900 °C. These observed results were supported by elemental balance analysis. These findings highlight that two-stage microwave and catalysis assisted pyrolysis could be a promising method for the efficient management of waste coffee pods, particularly for producing clean energy. [ABSTRACT FROM AUTHOR]

Copyright of Low-Carbon Chemistry & Chemical Engineering is the property of Low-Carbon Chemistry & Chemical Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Both plastics and CO2 are waste carbon resources, and their accumulation in nature has led to severe environmental pollution. However, simultaneously converting plastic waste and CO2 into value-added chemicals remains a challenge. Here we demonstrate a catalytic reforming process that converts plastics and CO2 into syngas over an electrified FeCrAl heating wire. The temperature of the electrified heating wire can quickly exceed 800 °C, facilitating the decomposition of polyethylene into gaseous hydrocarbons. The high-temperature heating wire promote the CO2 deoxygenation, resulting in the generation of CO, as well as the dehydrogenation of gaseous hydrocarbons. Significantly, the additional O species from CO2 and the carbon species from hydrocarbons can react to form CO, maintaining the high catalytic activity of the electrified heating wire. This novel approach is of paramount to achieving a circular economy in addressing the ongoing environmental crisis caused by the accumulation of plastic waste and excessive CO2 emissions. Simultaneously converting plastic waste and CO2 into value-added chemicals remains a challenge. Here, the authors demonstrate the feasibility of transforming waste plastics and CO2 into H2 and CO by utilizing solar irradiation via a photovoltaic system and an electrified FeCrAl heating wire. [ABSTRACT FROM AUTHOR]

Reforming ammonia to hydrogen using engine exhaust waste heat is a promising technology to improve the combustion performance and reduce the exhaust emissions of ammonia-fueled engines. However, there are still a research gap between the laboratory-level catalytic reforming tests and the practical application in engine systems. In particular, there are urgent needs to further understanding the ammonia reforming characteristics and developing the simulaiton models for the engine system optimization. In this paper, we conducted the experiments of catalytic reforming NH 3 to H 2 to study the effects of the reaction temperature, gas hour space velocity (GHSV) and pressure on the thermo-catalytic decomposition characteristicsxin. The results indicate that both the ammonia catalytic conversion and reforming efficiency exhibit an increasing trend with the rise in reaction temperature, while these two parameters demonstrate a decreasing trend with the increase in GHSV and pressure. The rate of hydrogen production is directly proportional to temperature, GHSV, and reaction pressure. Conversely, the energy required per unit of hydrogen production decreases with temperature but increases with GHSV and reaction pressure. The energy flow analysis shows that increasing the reforming temperature increases the reforming losses, but the total calorific value of the reformate increases, which is expected to improve the overall efficiency of ammonia fueled engines and reduce the unburned ammonia emissions. Simulation results show that, the improved Temkin-Pyzhev global rate model can significantly improve the accuracy of the ammonia catalytic decomposition process prediction. [Display omitted] • A novel energy flow analysis method for thermo-catalytic reforming is presented. • A precise predictive model for thermo-catalytic characteristics is established. • The thermo-catalytic system has a system efficiency of up to 94%. • The thermo-catalytic system has a reforming efficiency of up to 112%. [ABSTRACT FROM AUTHOR]

The advanced gasification technology of coal is mainly based on oxidation reaction and high temperature but is not suitable for biomass conversion. High tar and CO2 content are the two main issues that affect the efficiency of biomass gasification. In order to deeply convert hydrocarbons/tar and CO2 simultaneously, and enhance syngas yield, the cracking/partial oxidation/reforming reactions and their integrated reaction routes are investigated from an interrelated view. The effects of each reaction on the distribution of C/H elements in hydrocarbons/tar and syngas are illustrated. By cracking and oxidation reaction, the syngas yield can only reach 0.93 Nm3 kg−1, about 58 % of the theoretical maximum value; a large proportion of residual C/H atoms existing in stable hydrocarbons/tar/CO2/H2O are not converted. Based on the concept of lattice O oxidation combined with dry reforming, it realizes syngas yield (CO+H2) 1.56 Nm3 kg−1 with 91.6 % concentration, demonstrating that tar/hydrocarbons and CO2/H2O are converted to syngas efficiently. The effects of [O]/C ratio on gas yield represent a synergistic coordination between lattice Os oxidation and catalytic reforming reaction. Oxidation‐reforming is the optimum route for biomass conversion to high‐quality syngas. [ABSTRACT FROM AUTHOR]

The average annual global production of waste textiles exceeds 92 million tons, with the majority landfilled and incinerated, resulting in energy waste and environmental pollution. In this study, a thermal conversion process for waste textiles by gasification coupling with catalytic reforming under a steam atmosphere was proposed. The gasification performance of the waste textiles jumped with the introduction of steam and catalyst compared to pyrolysis at 800 °C. The syngas yield increased from 20.86 to 80.97 mmol/g and the hydrogen concentration increased from 17.79 to 50.91 vol.%, which was an increase of 288.12% and 186.18%, respectively. The excellent gasification performance mainly came from two sources: steam promotion for volatiles production and Fe-N-BC promotion for steam reforming of volatiles by Fe2O3, Fe3O4, Fe-Nx, etc. This study has achieved the efficient production of hydrogen-rich syngas from waste textiles, providing a new idea and theoretical basis for the effective removal and utilization of waste textiles. [ABSTRACT FROM AUTHOR]

This study investigates the impact of gas product recycling (GPR) on the performance of the steam methane reforming (SMR) process using nickel (Ni) and rhodium (Rh) catalysts. Hydrogen production, a cleaner alternative to fossil fuels, predominantly employs SMR due to its industrial efficacy. The study utilizes numerical simulations with Cantera software to evaluate the effects of recycling up to 30% of gaseous products at temperatures of 800, 1000, and 1200 Kelvin and a steam-to-methane ratio of 3. Key governing equations, including mass and energy conservation, as well as reaction kinetics described by the Arrhenius equation, are applied. The simulations reveal that GPR at 1200 K with a Ni catalyst enhances syngas production and reduces CO2 leakage, making it a viable option within the 20-30% recycling range. However, GPR at lower temperatures (800 K and 1000 K) for both Ni and Rh catalysts, and at 1200 K for Rh catalysts, results in undesirable increases in carbon deposition and CO2 production. Thus, GPR is generally not recommended for Rh catalysts due to significant coke formation. These findings underscore the potential benefits and limitations of GPR in optimizing SMR processes, particularly highlighting the suitability of Ni catalysts at higher temperatures. [ABSTRACT FROM AUTHOR]

• The catalytic reforming can efficiently convert waste plastics to CNTs. • The pyrolysis temperature significantly affects the volatilization composition. • Lower temperature promotes the formation of C 3 H 6 , C 2 H 6 and wax. • Higher temperature facilitates the generation of aromatic hydrocarbons. • Wax and small molecule hydrocarbons accelerate the growth of CNTs. Catalytic reforming offers a promising method for converting waste plastics into valuable products such as carbon nanotubes (CNTs). The composition of the carbon source plays a crucial role in determining the growth of CNTs because pyrolysis temperature exerts a significant influence on volatilisation. This study investigated the impact of pyrolysis temperature on the formation of CNTs in the presence of an Fe/Al 2 O 3 catalyst. A pyrolysis temperature of 500 ℃, generated a liquid product containing a high concentration of long-chain waxy hydrocarbons, while the gaseous products were dominated by C 3 H 6 (47 vol%) and C 2 H 6 (20 vol%). Increasing the pyrolysis temperature facilitated the formation of CH 4 and aromatic hydrocarbons at the expense of the waxy components. Following catalysis, carbon deposits of > 30 wt% (comprising approximately 80 % CNTs) were obtained at 500 ℃, compared to 20 wt% (with CNTs comprising 60 %) at 900 ℃. In summary, the results suggest that small molecular hydrocarbons, including C 3 H 6 and waxy components, promote CNT formation, whereas aromatic hydrocarbons contribute to the formation of amorphous carbon or coke. [ABSTRACT FROM AUTHOR]

The development of cost-effective and highly efficient biochar-based catalysts is essential for the catalytic steam reforming process of bio-oil. In this study, pickling peanut shell biochar was used to prepare biochar-supported Ni/Co monometallic catalyst and biochar-supported nickel-Co bimetallic catalyst through the impregnation method. The catalytic effect of these catalysts on acetic acid (a bio-oil model compound) steam reforming was investigated. It was found that Co could enhance the dispersion of metal particles. The catalyst exhibited the best catalytic effect and significantly improved resistance to carbon deposition with a loading of 8 wt% and a Ni-to-Co ratio of 6:2. At the temperature of 600 °C and the S/C ratio of 3, the selectivity of H2 reached 84.48 %, and the conversion of acetic acid reached 95.49 %. A synergistic effect was observed between Ni and Co, leading to increased metal dispersion, enhanced reducibility, and a higher number of active centers. Co facilitates water dissociation and promotes the oxidation of C–H and mobile O, resulting in a faster decarbonization rate. The effective utilization of biochar-based catalysts and the rational utilization of bio-oil contribute to the timely achievement of carbon emission reduction targets. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The European Union's (EU) decarbonization strategy involves hydrogen as an integral pillar. Since hydrogen is a secondary energy carrier, meaning it must be manufactured, not all hydrogen is made equal. Renewable hydrogen or RFNBOs (Renewable Fuel of Non-Biological Origins) have been given high priority by the EU in their strategy to establish a market for hydrogen. The EU's creation of RFNBO usage objectives is a step towards establishing a demand-side market. One such goal is to bring into the EU up to 10 million tonnes of renewable hydrogen. However, it is doubtful that this large amount can be reached given the strict criteria for what qualifies as renewable hydrogen and, thus, as RFNBO. This article analyses key provisions of the EU framework that affect the EU's aim to produce and import up to 20 million tonnes of hydrogen overall. It concludes the EU's emphasis on RFNBOs rather than a broader range of hydrogen pathways undermines the goal of rapidly developing a hydrogen market. Using turquoise hydrogen as a case study, the article shows how the EU's decarbonization efforts would be aided, trade would be enabled, and fragmentation would be decreased if targets were expanded to encompass additional forms of hydrogen. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) and methane (CH 4) are highly hazardous air pollutants that pose significant threats to the environment and human health and contribute indirectly to global warming. The dry reforming of methane (DRM) reaction has been investigated in numerous applications, including hydrogen production and catalytic converters. Catalytic DRM is one of the most effective approaches for utilizing CO 2 and CH 4 in syngas, which has garnered a lot of scholarly attention as a model reaction throughout the past couple of decades. Previous studies have extensively investigated the development of catalysts for DRM, with a particular emphasis on noble metal catalysts, catalyst configuration, and the influence of process parameters. However, despite the current understanding, there still needs to be a research gap in comprehending the synergistic interactions between catalytic activity and physicochemical features. Addressing this gap is of utmost importance. Therefore, a state-of-the-art review that clarifies new advancements for specific recently developed catalytic DRM systems with a complete evaluation and the synergistic link to physicochemical properties and their correlation with catalyst deactivation is critically urgent. Furthermore, in this study, we emphasized Ni-based catalysts as a promising option for DRM, given their potential, wide availability, and cost-effectiveness, owing to their high activity. Also, we discussed the limitations associated with this particular active metal. Additionally, this review integrates informetric analysis, employing robust search resources such as Web of Science. This analysis provides valuable insights into the DRM reaction, facilitating a deeper understanding of research trends and developments. This review can serve as a critical reference for scientists and experts engaged in mitigating CO 2 and CH 4 using DRM reactions and supports the academic and industrial sectors in their research and development efforts by contributing to developing well-designed catalysts suitable for future applications. [Display omitted] • A comprehensive review of the role of catalytic properties for Dry Reforming of Methane (DRM). • Rational and suitable design of catalysts for DRM were addressed. • Metal-support interaction, particle size, basicity, oxygen vacancies, reducibility, and porosity were elucidated. • Current challenges and future perspectives for DRM developments have been proposed. [ABSTRACT FROM AUTHOR]

The phenomenon of conservatively perturbed equilibrium (CPE) was applied to the processes of methane reforming (dry and steam reforming) and analyzed using kinetic computer simulations. This phenomenon was studied for two products, CO and H2, at different temperatures. "Unperturbed" species with inlet concentrations equal to the outlet equilibrium concentration experienced unavoidable passing through the temporary extremum (the CPE point), in this case, the maximum. Application of the CPE phenomenon to the complex catalytic methane reforming processes demonstrate two improvements: 1. Achieving the over-equilibrium product concentration. 2. This concentration is achieved at the reactor length that is much shorter than the length corresponding to the vicinity of the complete equilibrium. [ABSTRACT FROM AUTHOR]

This work studies red mud, a residue from the processing of bauxite, as a support catalyst in the thermocatalytic reforming (TCR) process, using wood, digestate, and straw as case studies. Thermocatalytic reforming is a thermochemical process for the conversion of biomass into biofuels, combining intermediate pyrolysis and catalytic reforming and resulting in high‐quality biofuels. The quantity and quality of the catalyst in the postreformer is vital as it influences the reactions taking place in it. Normally, nonreactive components of the char produced in the process act as the catalyst in the postreformer but adding a support catalyst may improve the products. In this work, red mud is introduced in the process by mixing it with the feedstock in a ratio of 1:3. The results, in comparison with normal TCR experiments on the same feedstock materials, show that the introduction of red mud into the process generally reduces the biochar yield and generally increases the biogas and product water yields, and the bio‐oil yield remains constant. Its introduction also increases the hydrogen fraction of the gas and tends to reduce the nitrogen and sulfur content of the products, thus improving their quality. These observations are consistent across feedstock materials and postreformer temperatures. The results therefore suggest that red mud is a good support catalyst for increasing the gas yield, increasing the hydrogen fraction of the gas, and improving the quality of the products from the TCR process. [ABSTRACT FROM AUTHOR]

Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new study from Canada has developed a process for efficiently extracting and recycling metals from used alkaline batteries. This method, called hydrometallurgy, uses aqueous solutions to extract the metals and is more cost-effective and energy-efficient than other methods. The researchers are now working on scaling up the technique for industrial use. The document also highlights various scientific studies in applied chemistry, including the conversion of carbon dioxide to carbon monoxide, the synthesis of synthetic diamonds, the growth of hydrocarbons from biogas, the reduction of CO2 to syngas and C2 hydrocarbons, the development of electronic spider silk sensors, the creation of reflective black paint for autonomous cars, the production of vanillin from ferulic acid, and the development of reversible supramolecular adhesives. Each study offers unique findings and potential applications in different fields. [Extracted from the article]

Catalytic studies hydrogen production via steam reforming of ethanol (SRE) are essential for process optimization. Likewise, selecting the ideal support for the active phase can be critical to achieve high conversion rates during the catalytic steam reforming process. In this work, copper-based catalysts were synthesized using two different supports, NaY zeolite and Nb2O5/Al2O3 mixed oxides. The materials were prepared using wet impregnation and characterized for their physicochemical properties using different analytical techniques. Differences in the catalyst morphologies were readily attributed to the characteristics of the support. The Cu/NaY catalyst exhibited a higher specific surface area (210.40 m2 g−1) compared to the Cu/Nb2O5/Al2O3 catalyst (26.00 m2 g−1), resulting in a homogeneous metal dispersion over the support surface. The obtained results showed that, at 300 °C, both the Cu/Nb2O5/Al2O3 and Cu/NaY catalysts produced approximately 50% hydrogen and 40% acetaldehyde, but with significant differences in conversion (6% and 56%, respectively). At 450 °C, a greater product distribution and a 10% higher conversion were observed when the catalyst was supported on NaY compared to Nb2O5/Al2O3. Hence, the performance of copper-based catalysts was influenced significantly by the textural properties of the support. [ABSTRACT FROM AUTHOR]

[Display omitted] • Incineration bottom ash (IBA) was good support for Ni in catalytic toluene reforming. • An activation stage was observed for Ni/IBA because of the metal-support interaction. • Formation of Ni-FeO x improves the redox ability and is responsible for activation. • Resistance to coking is due to the FeO x and alkali and alkaline earth metals in IBA. The incineration bottom ash (IBA) was impregnated with nickel to catalyze toluene (tar surrogate) steam reforming. A toluene conversion of >80 % was achieved at 800℃ without activity decay in a 100-h test for 15 %Ni/IBA. An activation stage was observed for Ni/IBA catalysts in the initial 50 ∼ 400 min under different reaction conditions. A series of experiments and characterizations were performed to explore the possible mechanisms for the activation. It was found that the iron species in IBA gradually migrated to the catalyst surface and formed a Ni-FeO x complex owing to the metal-support interaction. The synergy of Ni-FeO x played an important role in improving the activity of Ni/IBA due to the enhanced lattice oxygen activity. Additionally, Ni/IBA catalysts showed a much lower coke deposition rate than Ni/Al 2 O 3 (1.12 vs. 3.45 mg-C/g cat ∙h) because of the variable states of FeO x and the abundant basic sites caused by the alkali and alkaline earth metals contained in IBA. [ABSTRACT FROM AUTHOR]

As a sustainable and promising approach of removing of nitrogen oxides (NOx), catalytic reduction of NOx with H2 is highly desirable with a precise understanding to the structure-activity relationship of supported catalysts. In particular, the dynamic evolution of support at microscopic scale may play a critical role in heterogeneous catalysis, however, identifying the in situ structural change of support under working condition with atomic precision and revealing its role in catalysis is still a grand challenge. Herein, we visually capture the surface lattice expansion of WO3-x support in Pt-WO3-x catalyst induced by NO in the exemplified reduction of NO with H2 using in situ transmission electron microscopy and first reveal its important role in enhancing catalysis. We find that NO can adsorb on the oxygen vacancy sites of WO3-x and favorably induce the reversible stretching of W-O-W bonds during the reaction, which can reduce the adsorption energy of NO on Pt4 centers and the energy barrier of the rate-determining step. The comprehensive studies reveal that lattice expansion of WO3-x support can tune the catalytic performance of Pt-WO3-x catalyst, leading to 20% catalytic activity enhancement for the exemplified reduction of NO with H2. This work reveals that the lattice expansion of defective support can tune and optimize the catalytic performance at the atomic scale. [ABSTRACT FROM AUTHOR]

Thermochemically upcycling waste plastics to value-added products is emerging to alleviate the waste crisis. This study aims to develop highly active and stable Ni-based catalysts for coupling pyrolysis and catalytic reforming of waste plastics to produce syngas. A series of confined NiO@S-1 catalysts with various Ni loadings (5%, 10%, 15%, and 20%) were constructed by employing dissolution-recrystallization strategy. They were in situ reduced and 15%NiO@S-1 sample showed the highest catalytic activity in terms of yield of syngas with high CO selectivity and was superior to 15%NiO/S-1 and 15%NiO/SiO 2 samples prepared by impregnation method. The TEM images of 15%NiO@S-1 catalyst after reaction showed that metallic Ni nanoparticles with average size of 10.1 nm were kept dispersive due to the confinement effect. In contrast, the apparent agglomeration of Ni nanoparticles with average size of 54.9 nm were found on the surface of 15%NiO/S-1 after reaction. This provides an effective strategy for design robust Ni-based confined catalysts for thermochemically upcycling waste plastics. [Display omitted] • Pyrolysis and catalytic O 2 reforming technology was used to produce syngas from polypropylene. • NiO@S-1 catalyst showed higher catalytic activity than NiO/S-1 and NiO/SiO 2. • The migration and agglomeration of Ni particles was limited in NiO@S-1 catalyst. • No evident coke was observed on the surface of NiO@S-1 catalyst after reaction. [ABSTRACT FROM AUTHOR]

The x%Ni/Sm2O3-MnO (x = 0, 10, 15, 20) catalysts derived from SmMn2O5 mullite were prepared by solution combustion and impregnation method; auto-thermal reforming (ATR) of acetic acid (HAc) for hydrogen production was used to explore the metal-support effect induced by Ni loadings on the catalytic reforming activity and product distribution. The 15%Ni/Sm2O3-MnO catalyst exhibited optimal catalytic performance, which can be due to the appropriate Ni loading inducing a strong metal–support interaction to form a stable Ni/Sm2O3-MnO active center, while side reactions, such as methanation and ketonization, were well suppressed. According to characterizations, Sm2O3-MnO mixed oxides derived from SmMn2O5 mullite were formed with oxygen vacancies; nevertheless, loading of Ni metal further promoted the formation of oxygen vacancies, thus enhancing adsorption and activation of oxygen-containing intermediate species and resulting in higher reactivity with HAc conversion near 100% and hydrogen yield at 2.62 mol-H2/mol-HAc. [ABSTRACT FROM AUTHOR]

The effect of high concentrations of H2S in sour natural gas on the catalytic dry reforming of methane (DRM) process has seldom been studied previously in the literature. Herein, several types of catalysts, including MgO, NiO/MgO, and LaNiO3 in different states, were prepared for conducting DRM at 800 °C and 0.1 MPa in a feed of 20 vol% CO2 and 20 vol% CH4, and their catalytic performance under conditions of the absence and presence of H2S was compared. A promotion effect of increasing H2S concentration on both the conversions of CO2 and CH4 and the molar yields of CO and H2 was observed on all the catalysts and was particularly remarkable on the MgO and the pristine NiO/MgO. For NiO/MgO, the addition of 15 vol% H2S increased the conversion of CH4 from 6.92% to 26.86% and CO2 from 9.15% to 42.10%. While there was a significant decline in the catalytic activity of the reduced NiO/MgO and LaNiO3 catalysts after adding H2S, moderate reactant conversions were still sustained. The results of process analysis and catalyst structure characterization suggest that H2S participation can contribute to the increment in CO2 and CH4 conversion, and active S-adsorbed species may play the key role of catalysis in reactions involving H2S. [ABSTRACT FROM AUTHOR]

This document provides summaries of various scientific research papers. The first summary discusses the development of aerogel fibers that mimic the thermal insulation properties of polar bear hairs. The second summary highlights the creation of bacteria-grown vegan leather that dyes itself, offering a more sustainable alternative to traditional leather production. The third summary discusses the use of pyroelectrochemical cells for powering wireless devices in the Internet of Things. The fourth summary mentions the development of self-cleaning paints using photocatalytically active nanoparticles. The fifth summary describes a high-pressure electro-Fenton process for converting methane to formic acid. The sixth summary introduces a hybrid membrane-free cell for hydrogen production. The seventh summary discusses the use of nanoparticles derived from food waste to recover gold from electronic waste. The eighth summary mentions a nonthermal plasma-based strategy for carbon growth from biogas constituents. The ninth summary highlights the use of a bifunctional catalyst for efficient hydrogen production. The tenth summary discusses the selective conversion of methanol into high-purity hydrogen and carbon monoxide. [Extracted from the article]

Gas fermentation is gaining attention as a crucial technology for converting gaseous feedstocks into value-added chemicals. Despite numerous efforts over the past decade to investigate these innovative processes at a lab scale, to date, the evaluation of the technologies in relevant industrial environments is scarce. This study examines the fermentative production of acetate from biomass-derived syngas using Moorella thermoacetica. A mobile gas fermentation pilot plant was coupled to a bubbling fluidized-bed gasifier with syngas purification to convert crushed bark-derived syngas. The syngas purification steps included hot filtration, catalytic reforming, and final syngas cleaning. Different latter configurations were evaluated to enable a simplified syngas cleaning configuration for microbial syngas conversion compared to conventional catalytic synthesis. Fermentation tests using ultra-cleaned syngas showed comparable microbial growth (1.3 g/L) and acetate production (22.3 g/L) to the benchmark fermentation of synthetic gases (1.2 g/L of biomass and 25.2 g/L of acetate). Additional fermentation trials on partially purified syngas streams identified H2S and HCN as the primary inhibitory compounds. They also indicated that caustic scrubbing is an adequate and simplified final gas cleaning step to facilitate extended microbial fermentation. Overall, this study shows the potential of gas fermentation to valorize crude gaseous feedstocks, such as industrial off-gases, into platform chemicals. [ABSTRACT FROM AUTHOR]

Hypersonic vehicles as next-generation aircraft have broad applications, but existing technologies of onboard power generation are hardly applicable due to the change of engines. In this research, a catalytic steam reforming enhanced closed-Brayton-cycle power generation system based on is developed. This system combines the closed Brayton cycle (CBC) and catalytic steam reformed fuel vapor turbine (CSRFVT) to supply electric power. The zero-dimensional models of CBC and the CSRFVT are established to evaluate system performance. Results indicate the products with a water content of 30% have the strongest working ability, which can reach 330 kJ/kg. Moreover, the thermal efficiency and electric power of the parallel arrangement are higher than that of the series arrangement. Besides, the lower pressure of water is beneficial to the electric power. However, the difference in electric power between various pressures is less than 1 kW. In addition, under the same heat absorption, the total electric power of the system based on fuel and water is higher, and the former's outlet temperature of cooling channels is lower. The maximum total electric power of the novel system is about 120 kW. This research provides an innovative technical solution for the power generation of hypersonic vehicles. • A novel power generation system based on hydrocarbon fuel and water is proposed. • A zero-dimensional model of the system performance is established. • The products with a water content of 30% have the strongest working ability. • The maximum total electric power of this system is 120 kW at Ma 6. Abstract. [ABSTRACT FROM AUTHOR]

Amine modification through nucleophilic attack of the amine functionality is a very common chemical transformation. Under biorelevant conditions using acidic-to-neutral pH buffer, however, the nucleophilic reaction of alkyl amines (pKa ≈ 10) is not facile due to the generation of ammonium ions lacking nucleophilicity. Here, we disclose a unique molecular transformation system, catalysis driven by amyloid-substrate complex (CASL), that promotes amine modifications in acidic buffer. Ammonium ions attached to molecules with amyloid-binding capability were activated through deprotonation due to the close proximity to the amyloid catalyst formed by Ac-Asn-Phe-Gly-Ala-Ile-Leu-NH2 (NL6), derived from islet amyloid polypeptide (IAPP). Under the CASL conditions, alkyl amines underwent various modifications, i.e., acylation, arylation, cyclization, and alkylation, in acidic buffer. Crystallographic analysis and chemical modification studies of the amyloid catalysts suggested that the carbonyl oxygen of the Phe-Gly amide bond of NL6 plays a key role in activating the substrate amine by forming a hydrogen bond. Using CASL, selective conversion of substrates possessing equivalently reactive amine functionalities was achieved in catalytic reactions using amyloids. CASL provides a unique method for applying nucleophilic conversion reactions of amines in diverse fields of chemistry and biology. [ABSTRACT FROM AUTHOR]

One promising idea to use excess glycerol generated during biodiesel fabrication is to produce hydrogen (H2) via the steam reforming of glycerol (GSR). This study combined GSR and water-gas shift (WGS) reactors to minimize energy usage and carbon monoxide (CO) emissions while augmenting H2 production. Choice of a Ni/γ-Al2O3 catalyst for the GSR reaction at 0.101 MPa and 923 K resulted in a product stream having 66.12% and 9.68% H2 and CO, respectively. For the WGS reactor, a Pt/HAP catalyst achieved 100% conversion of CO at 0.101 MPa and 723 K. Combining the two catalysts at an optimized temperature of 923 K for over 15 h resulted in H2 and CO levels at 69.85% and 1.77%, respectively: thus, increasing the production rate of H2 by 5% while reducing CO by 81%. Coking did occur during the GSR reaction. Overall, the combined reactor has potential to reduce complexity and energy usage. [ABSTRACT FROM AUTHOR]

Catalytic aqueous‐phase reforming (APR) of wet biomass such as microalgae and activated sludge is a potential technique for the production of H2‐rich gaseous products. In the present work, model compounds such as ethylene glycol, xylose and alanine were selected as representatives of the polyols, carbohydrates and proteins in wet biomass. APR trials were performed in a stirred batch reactor using commercial Pt/Al2O3 and Ru/Al2O3 catalysts. The reforming reactions were investigated at different conditions: temperature (T), 498 to 518 K, feed concentration, 1 to 5 wt. %, catalyst loading (ω), 2 to 6 kg/m3, and reaction time (t), 1 to 6 h. The commercial Pt/Al2O3 catalyst exhibited higher reforming activity. The influence of reaction parameters on turnover frequency (TOFH₂), hydrogen yield (Y‐H2) and carbon‐to‐gas conversion (C to G conversion) was studied. The values of TOFH₂ for Pt/Al2O3 were measured at T = 518 K, ω = 2 kg/m3 and t = 3 h using 1 wt% feed and these values were 19.2, 4 and 6 1/min for ethylene glycol, xylose and alanine. The values of TOFH₂ over Ru/Al2O3 under identical conditions were: ethylene glycol–12.4, xylose–1.4 and alanine–5.4 1/min. The activation energies for H2 production from ethylene glycol, xylose and alanine over Pt/Al2O3 and Ru/Al2O3 catalysts were determined. APR of the mixture of model compounds was also studied over laboratory‐made Pt/Al2O3 and Ru/Al2O3 catalysts at the optimum reaction conditions. Thus, this work has provided crucial insights into the production of H2 from model compounds of wet biomass using Al2O3‐supported catalysts. [ABSTRACT FROM AUTHOR]

Recently, there has been a notable surge in interest regarding reclaiming valuable chemicals from waste plastics. However, the energy-intensive conventional thermal catalysis does not align with the concept of sustainable development. Herein, we report a sustainable electrocatalytic approach allowing the selective synthesis of glycolic acid (GA) from waste polyethylene terephthalate (PET) over a Pd67Ag33 alloy catalyst under ambient conditions. Notably, Pd67Ag33 delivers a high mass activity of 9.7 A mgPd -1 for ethylene glycol oxidation reaction (EGOR) and GA Faradaic efficiency of 92.7 %, representing the most active catalyst for selective GA synthesis. In situ experiments and computational simulations uncover that ligand effect induced by Ag incorporation enhances the GA selectivity by facilitating carbonyl intermediates desorption, while the lattice mismatch-triggered tensile strain optimizes the adsorption of *OH species to boost reaction kinetics. This work unveils the synergistic of strain and ligand effect in alloy catalyst and provides guidance for the design of future catalysts for PET upcycling. We further investigate the versatility of Pd67Ag33 catalyst on CO2 reduction reaction (CO2RR) and assemble EGOR//CO2RR integrated electrolyzer, presenting a pioneering demonstration for reforming waste carbon resource (i.e., PET and CO2) into high-value chemicals. [ABSTRACT FROM AUTHOR]

The fine regulation of catalysts by the atomic-level removal of inactive atoms can promote the active site exposure for performance enhancement, whereas suffering from the difficulty in controllably removing atoms using current micro/nano-scale material fabrication technologies. Here, we developed a surface atom knockout method to promote the active site exposure in an alloy catalyst. Taking Cu3Pd alloy as an example, it refers to assemble a battery using Cu3Pd and Zn as cathode and anode, the charge process of which proceeds at about 1.1 V, equal to the theoretical potential difference between Cu2+/Cu and Zn2+/Zn, suggesting the electricity-driven dissolution of Cu atoms. The precise knockout of Cu atoms is confirmed by the linear relationship between the amount of the removed Cu atoms and the battery cumulative specific capacity, which is attributed to the inherent atom-electron-capacity correspondence. We observed the surface atom knockout process at different stages and studied the evolution of the chemical environment. The alloy catalyst achieves a higher current density for oxygen reduction reaction compared to the original alloy and Pt/C. This work provides an atomic fabrication method for material synthesis and regulation toward the wide applications in catalysis, energy, and others. [ABSTRACT FROM AUTHOR]

Dihydrogen, commonly named 'hydrogen', is a carbon–neutral and renewable fuel meeting environmental regulations in transportation and industrial production. Hydrogen is currently employed in fuel cells, hydrogen vehicles, and as an efficient energy carrier due to its high energy capacity of 121 kJ per g. Here we review hydrogen production by steam reforming of alcohols including methanol, ethanol, propanol, glycerol and butanol, with focus on catalysts, mechanisms, and analytical methods to characterize deposited carbon. In general, Ru- and Rh-based catalysts show efficient performance with almost 100% feedstock conversion and up to 89% of hydrogen yield, while Ni and Co catalysts exhibit lower ethanol conversion in the range of 40–100% depending on operating conditions. Nevertheless, Ni and Co catalysts have been mainly chosen as active metals for alcohols steam reforming due to their lower cost. [ABSTRACT FROM AUTHOR]

Reformer heater tubes operate in a complex environment involving high temperatures, pressure, and corrosive atmospheres. Depending on the operating conditions, several mechanisms can occur, such as creep, oxidation, high-temperature hydrogen attack, and carburization. This paper aims to evaluate the degradation degree of catalytic reformer heater tubes made of ferritic alloy-steel A 335 grade P22 based on a combination of inspection techniques, including visual inspection, microstructure observation, metallographic analysis, and mechanical properties testing. The results show severe oxidation and scaling occurring on the outer surface of the heater tube due to operating the tubes above recommended levels. Several recommendations are suggested to reduce the risk of thermal oxidation and prevent similar damages from reoccurring in the future. [ABSTRACT FROM AUTHOR]

The catalytic reforming of bioethanol can produce green hydrogen (H2) and acetic acid (AcOH). In the present study, the conversion of aqueous ethanol (EtOH) over 4 wt%Ru-4 wt%Sn/TiO2 in a flow reactor was investigated at different temperatures at 0.1 MPa or at various pressures at 260 °C. The ethanol conversion was rather slow in liquid water, while the reactivity increased significantly when water was evaporated. Under gas-phase conditions at 0.1 MPa, the conversion rate increased with increasing reaction temperature, but the AcOH yield and H2 purity decreased due to by-production of CH4, CO, and CO2. The CH4 and CO generated by fragmentation of acetaldehyde (AA), an intermediate, were suppressed by increasing reaction pressure, although the formation of CH4 and CO2 generated from AcOH was pressure independent. Thus, the highest-pressure conditions in steam at a given reaction temperature are preferred for the production of pure H2. The initial step, EtOH → AA, was the rate-determining reaction, and the model experiments using AA as a substrate showed that the Cannizzaro reaction of two AA molecules to form EtOH and AcOH occurred preferentially. This oxidation system was confirmed to be effective at EtOH concentrations of up to 500 g/L in water. [ABSTRACT FROM AUTHOR]

The atomic structure and chemical behavior of heterocyclic fragments, such as pyridine, thiophene, and furan, in oil shale are crucial for optimizing its thermal pyrolysis process. This study employs density functional theory (DFT) to investigate the atomic structure and reactivity of typical heterocyclic fragments with impurities such as sulfur, nitrogen, and oxygen in kerogen macromolecules—the main organic compound of oil shale. By analyzing the free energy barriers, reaction rates and half-lives, we found that oxygen-containing heterocyclic compounds exhibited higher pyrolysis efficiency compared to nitrogen- and sulfur-containing heterocyclic compounds at the same temperature. We also analyzed the electrostatic potential and natural population analysis charges of the heterocyclic compounds and discovered that nitrogen- and sulfur-containing heterocycles had negative electrostatic potentials, making them more susceptible to electrophilic reactions. These findings provide valuable insights into the mechanisms and kinetics of various processes involved in oil shale processing, which can inform the development of more efficient and sustainable oil shale utilization strategies. [ABSTRACT FROM AUTHOR]

As non-noble metal catalyst, Cu-based catalyst shows promising applying potential in the aqueous-phase reforming of methanol (APRM) due to its high dehydrogenation activity and low CO selectivity, but the poor thermal and hydrothermal stability. Herein, a Cu@S-1 catalyst with ultrasmall-2nm Cu nanoparticles size was synthesized for the first time using one-step in-situ encapsulation strategy. By the confinement effect of the zeolite Silicalite-1 (S-1) micropores, the 1 wt%Cu@S-1 catalyst exhibited absolutely superior thermal stability without using any other promoter, as well as relatively good hydrothermal stability. After 600–700 °C high-temperature treatment, no obvious aggregation of the Cu nanoparticles was found, and superior performance in the steam reforming of methanol (SRM) was maintained after running for 36 h at 300 °C. In the APRM at 210 °C, the 1 wt%Cu@S-1 catalyst showed six-fold higher hydrogen releasing rate (4.26 × 105 μ mo l H 2 · g Cu − 1 · h − 1 ) than the impregnated 1 wt%Cu/S-1-im catalyst, meanwhile it exhibited even better performance than the commercial 5%Pd/C catalyst. Compared with the impregnated 1 wt%Cu/S-1-im catalyst, the confinement effect of the internal pores of the S-1 for the Cu nanoparticles in the 1 wt%Cu@S-1 catalyst effectively inhibited aggregation of the Cu particles and Cu leaching in APRM, thus greatly improved the activity and hydrothermal stability. [Display omitted] • In-situ encapsulation of ultrasmall-2nm Cu particles in the pores of zeolite S-1. • A high hydrogenation production rate of 4.26 × 105 μ mo l H 2 · g Cu − 1 · h − 1 over the Cu@S-1. • 6-fold higher APRM activity over the Cu@S-1 than over the impregnated catalyst. • Superior thermal and relatively good hydrothermal stability over the Cu@S-1. • Largely prohibited aggregation and leaching of Cu via confinement strategy. [ABSTRACT FROM AUTHOR]

High-entropy alloy nanoparticles (HEANs) possessing regulated defect structure and electron interaction exhibit a guideline for constructing multifunctional catalysts. However, the microstructure--activity relationship between active sites of HEANs for multifunctional electrocatalysts is rarely reported. In this work, HEANs distributed on multi-walled carbon nanotubes (HEAN/CNT) are prepared by Joule heating as an example to explain the mechanism of trifunctional electrocatalysis for oxygen reduction, oxygen evolution, and hydrogen evolution reaction. HEAN/CNT excels with unmatched stability, maintaining a 0.8V voltage window for 220 h in zinc-air batteries. Even after 20 h of water electrolysis, its performance remains undiminished, highlighting exceptional endurance and reliability. Moreover, the intrinsic characteristics of the defect structure and electron interaction for HEAN/CNT are investigated in detail. The electrocatalytic mechanism of trifunctional electrocatalysis of HEAN/CNT under different conditions is identified by in situ monitoring and theoretical calculation. Meanwhile, the electron interaction and adaptive regulation of active sites in the trifunctional electrocatalysis of HEANs were further verified by density functional theory. These findings could provide unique ideas for designing inexpensive multifunctional high-entropy electrocatalysts. [ABSTRACT FROM AUTHOR]

Alpha-L-arabinofuranosidase (α-L-AFase) belongs to glycosyl hydrolases. Its main function is to hydrolyze the arabinose substituents in arabinoxylan and promote the hydrolysis of hemicellulose with other hydrolases synergistically, so as to improve the biotransformation rate of hemicellulose. In this article, the recent research advances on the enzymatic characteristic and its improvement, structure, catalytic mechanism and synergistic catalytic effect of α-L-AFase from microorganisms are reviewed. It is found that the physicochemical properties, molecular structures and catalytic mechanisms of α-L-AFases from different microbial sources are diverse, and the method of recombinant expression could effectively improve the enzymatic activity and stability of α-L-AFase. This synergistic catalysis of α-L-AFase with other hemicelluloses hydrolases can significantly improve the substrate conversion efficiency. α-L-AFase has been widely used in many fields such as improving the texture of fermented dough, juice clarification, optimizing the brewing technique, preparation of high digestion feed, and preparing the functional health products. This review provides some references for the subsequent fundamental research, development and utilization of α-L-AFase in the future. [ABSTRACT FROM AUTHOR]

The electro-Fenton process is a state-of-the-art water treatment technology used to remove organic contaminants. However, the low O2 utilization efficiency (OUE, <1%) and high energy consumption remain the biggest obstacles to practical application. Here, we propose a local O2 concentrating (LOC) approach to increase the OUE by over 11-fold compared to the conventional simple O2 diffusion route. Due to the well-designed molecular structure, the LOC approach enables direct extraction of O2 from the bulk solution to the reaction interface; this eliminates the need to pump O2/air to overcome the sluggish O2 mass transfer and results in high Faradaic efficiencies (~50%) even under natural air diffusion conditions. Long-term operation of a flow-through pilot device indicated that the LOC approach saved more than 65% of the electric energy normally consumed in treating actual industrial wastewater, demonstrating the great potential of this system-level design to boost the electro-Fenton process for energy-efficient water remediation. [ABSTRACT FROM AUTHOR]

The pyrolytic reforming of toluene to hydrogen and CNTs over the commercial and self-prepared Al 2 O 3 loaded with Fe through the impregnation method is investigated in a fixed bed reactor under the temperature from 600 °C to 800 °C. The physicochemical properties of Fe–Al 2 O 3 catalysts and Al 2 O 3 supports were characterized by XPS, H 2 -TPR, HRTEM and H 2 -pulse chemisorption. The reforming process over the catalyst of Fe loaded on self-prepared Al 2 O 3 gives the excellent H 2 yield of 27.8 mmol/(g-Fe) and graphite yield of 82.6 wt%, which is much higher than those from that over the catalyst of Fe loaded on the commercial Al 2 O 3. It is evidenced by H 2 -pulse chemisorption that 5.1 % of Fe0+ dispersion over the commercial Al 2 O 3 with mainly-exposed (110) facet while 11.2 % of Fe0+ dispersion over self-prepared Al 2 O 3 with mainly-exposed (111) facet were obtained. The adsorption energy of iron cluster (Fe 4) with Al 2 O 3 (111) facet was estimated to be −14.5 eV through the DFT simulation, which is notably higher than that of iron cluster (Fe 4) with Al 2 O 3 (110) facet as −9.1 eV. With regard to the MD simulation along with XRD analysis of the Fe 3 C crystallite, Fe0+ particles can be prominently molten at the high Fe0+ dispersion over Al 2 O 3 facet, promoting the carbon solubility for the assembly of multi-wall CNTs without the deposition of unwanted amorphous carbon. [Display omitted] • The influence of γ-Al 2 O 3 on Fe–Al 2 O 3 catalytic performance was investigated. • The crystal-facet effect of γ-Al 2 O 3 on metal Fe dispersion was evidenced. • The melting process over Fe nanoparticles with different sizes was simulated. • The interaction between γ-Al 2 O 3 and Fe 4 cluster was calculated via DFT theory. [ABSTRACT FROM AUTHOR]

In the presented work, the process of heat and mass transfer inside an original design nozzle for a catalytic reformer of diesel fuel in a low-mass-flux mode is investigated by direct numerical simulation using Open FOAM open-source code. The main goal of a new nozzle design is to increase the rate and degree of fuel evaporation, as well as to improve the mixing characteristics of diesel fuel with superheated water vapor before the reaction mixture passes through the catalyst. Inside the nozzle, there are two regions where flows with opposite swirl directions are created; this leads to a strong velocity shear inside the nozzle, intensifying the mixing processes. Simulations were carried out in the Eulerian-Lagrangian formulation, taking into account the processes of evaporation of fuel droplets. The simulation results show that the flow at the outlet of the nozzle has a good uniformity of the mixture composition and provides a high degree of fuel evaporation at the early stages of flow development. [ABSTRACT FROM AUTHOR]

This is an essay in the field of ceramics and composites.With the increasing demand for crude oil processing technology, China′s platinum rhenium catalyst industry is also developing. Catalyst is the core material of petroleum smelting, and impregnation method is the most important preparation method of reforming catalyst. Catalytic reforming catalysts generally refer to trace rhenium catalysts. The main research direction in the future is to increase the rhenium content of the catalyst and reduce the amount of platinum in the catalyst. The characteristics of platinum-rhenium catalysts are good stability, slightly poor selectivity, long-term stable operation, and regeneration cycle that can reach 3~5 years, which have been widely used in large-scale production of semi-regenerative reforming processes. Since the late 20th century, China′s refining catalyst market has formed a′Sinopec and PetroChina′s catalyst companies, supplemented by private catalyst companies′ market structure, catalyst demand is stable at more than 10 tons per year.

The use of hydrogen as an energy carrier has increased for reasons related to its environmentally friendly characteristics. The most common and low-cost method of producing hydrogen from natural gas (or CH 4) is the steam reforming process. The 2-D axisymmetric catalytic membrane reactor (CMR) model is developed for pure hydrogen production from real natural gas (NG) using a Pd–Ru membrane with a Ni/Al 2 O 3 catalyst. In this paper, a CFD model is prepared to investigate the performance of a catalytic membrane reactor through natural gas conversion and hydrogen production under various operation parameters, i.e., temperature of reaction in the range of 600, 700, 800, 900, and 1000 K, gas hourly space velocity GHSV with a range of 500, 700, 1000, 2000, and 3000 h−1, and sweep gas flow rate (Re No.) 1, 50, 100, 150, and 250. The results of the simulation show that the CMR exhibits a high permeation rate of hydrogen on the permeate side (tube side) and achieves a high methane conversion rate of approximately 99.9 % at 1000 K on the retentate side. The hydrogen flux exhibits a decline as the temperature increases from 900 to 1000 K, despite the achievement of complete (NG) conversion. Hence, it can be concluded that the performance of the catalytic membrane reactor (CMR) process exhibits a pattern of increase when the other parameters, such as (GHSV) and (Re.No.), are increased. • 2D axisymmetric CFD simulation of non-isothermal model for natural gas steam reforming in a catalytic membrane reactor (CMR). • Kinetic model for endo/exo-thermic reactions of methane, ethane and propane in NG of AMARA field is applied. • The effect of reaction temperature, GHSV and sweep gas flowrates on CMR performance are studied. • Optimum conditions for maximum of methane conversion and hydrogen flux are suggested. [ABSTRACT FROM AUTHOR]

This study investigated the role of K and steam in upgrading syngas quality over biochar in a two-stage fixed-bed reactor. The integration of K-char catalyst and steam greatly increased syngas (H 2 +CO) and H 2 production. The syngas products yield (19.76 mmol/g biomass) and a H 2 yield (11.14 mmol/g biomass) were achieved when K-char was used as catalyst in the presence of steam. In general, four ways could be concluded to promote volatiles reforming to improve syngas quality by K and steam: Firstly, K and steam interaction with biochar increased the surface area and developed the porous structure of biochar, providing the pyrolytic intermediates with full complete contact with the char surface, and improving the chance of contact with the active sites. Secondly, the condensation reactions of biochar were inhibited by K and steam, thus preventing the reduction of active groups on the aromatic ring of biochar. Thirdly, K and steam promoted the formation of O-containing groups with high reactive activity on the char surface, such as –COO and –CO. Moreover, volatile K migrated in biochar matrix during catalytic reforming, and steam inhibited the release of K in biochar, resulting in more K retaining on the char surface in the form of -COK and -COOK acting as the active sites, which ultimately improved the catalytic activity of biochar, and promoted tar destruction and hydrocarbon reforming. [Display omitted] • K-form char combined with steam greatly increased syngas (H 2 +CO) and H 2 production. • Steam, carbon skeleton and K in biochar improved the secondary catalytic reforming reaction efficiency. • The catalytic effect of biochar is related to its surface area, O-containing groups and K migration. • Mechanism of K-form char combined with steam to improve syngas quality is well discussed. [ABSTRACT FROM AUTHOR]