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The increasing global demand for fuel, along with pressing environmental regulations and concerns, and the need for energy security, all point to the biofuel industry seeing rapid growth in the near future. The objective of this study was to study the performance of a series of activated carbon (AC) supported La and Ce oxide catalysts in the catalytic cracking of waste cooking oil into alkane-based hydrocarbon. Coconut-shell activated carbon was loaded with various amounts of lanthanum and cerium were prepared via wet impregnation. The catalytic cracking activity was evaluated in a fixed bed reactor under N2 flow at 450 °C and a weight hourly space velocity of 8 h−1 at 60 min. The physical and chemical properties of the prepared catalysts were characterized by BET, SEM–EDX, XRD, TPD-NH3/CO2, FTIR, and TGA. The results indicated that 5 wt% La/AC performed superiorly with a liquid product of 87.03% which composed of 99.09% hydrocarbons, that were mostly alkane (79.89%) with n-(C15 + C17) 66% selectivity (66.13%). [ABSTRACT FROM AUTHOR]

Modelling catalytic fixed bed reactors with a small tube-to-particle diameter ratio requires a detailed description of the interactions between fluid flow, intra-particle transport, and the chemical reaction( s) within the catalyst. Particle-resolved computational fluid dynamics (PRCFD) simulations are the most promising approach to predict the behaviour of these reactors accurately, since they take into account the local packed bed structure explicitly. In this work, a conjugated heat and mass transfer model for use in PRCFD simulations is presented in order to couple the fluid flow through the fixed bed with transport and reaction in the porous catalyst, while guaranteeing the no-slip boundary condition at the fluid-solid interface. For this purpose, the solutions of the solid and fluid domain are computed separately and are coupled by calculation and updating the boundary condition at the particle surface. Owing to the consideration of secondary gradients, the developed transfer model is also valid for unstructured calculation meshes containing non-orthogonal cells at the fluid-solid interface. Such meshes are often used to resolve complex geometries, such as a packed bed, in a computationally efficient manner. The coupling approach is validated using cases for which an analytical solution or literature correlations derived from experimental data are available. The simulation results of a short catalytic packed bed with rings catalysing the partial oxidation of n-butane to maleic anhydride exemplify the potential of PRCFD involving reactions to analyse the catalyst performance in great detail. [ABSTRACT FROM AUTHOR]

Water gas shift (WGS) reaction commonly converts CO to CO 2 using H 2 O and produces H 2 and CO 2 in a catalytic fixed bed reactor. This study aims to develop a Cu/ZnO/ZSM-5 catalyst loaded in water gas shift reactor for converting typical synthesis gas produced from dry reforming of methane (DRM) at medium temperature shift (MTS, 200–350 oC) conditions and for preventing reverse reaction due to high feed concentrations of CO 2 and H 2. The Cu/ZnO/ZSM-5 catalyst was prepared by impregnation method with lower Cu metal loading of 5, 10, and 15 wt%, respectively, compared to commercial catalysts. The synthesized catalyst was characterized using XRF, XRD, SEM, H 2 -TPR, NH 3 -TPD, and TGA. The catalyst activity and stability for the WGS reaction were tested in the fixed bed reactor at atmospheric pressure and temperature of 325 °C. The experimental results show that CO conversion increases with increasing Cu loading. The 15 wt% Cu/ZnO/ZSM-5 catalyst showed the best results with a CO conversion of 35% and a yield of H 2 of 36% and showed good stability for 32 h. Based on the TGA, the 15 wt% Cu/ZnO/ZSM-5 catalyst forms a 0.04 g carbon/g catalyst, which is much lower when compared to commercial catalyst (0.105 g carbon/g catalyst). The relative activity of the synthesized catalyst indicates 2.4 times better when compared to commercial catalysts. High concentrations of H 2 and CO 2 in the feed may initiate side reactions, including reverse WGS, methanation, and carbon formation, which will decrease H 2 yield. • Cu/ZnO/ZSM-5 catalyst boosts CO conversion to 35% at 325 °C in WGS reaction. • 15 wt% Cu/ZnO/ZSM-5 achieves 36% H2 yield with 32-h stability in WGS. • Carbon formation is 0.04 g/g, lower than commercial catalyst's 0.105 g/g. [ABSTRACT FROM AUTHOR]

Sorption-enhanced steam reforming (SESR) is a promising intensified strategy for producing highly pure hydrogen through in-situ CO 2 removal by a sorbent. This work experimentally explores the SESR of simulated bio-oil (mixture of acetic acid, acetone, ethanol, and phenol) over Ni/CaO-based bifunctional materials (BFMs) stabilized by industrial wastes (i.e., fly ash (FA) and UpGraded Slag Oxides (UGSO)) in a fixed bed reactor. The impact of CO 2 concentration and steam on the sorption efficiency of BFM-UGSO was investigated and the most likely carbonation route of BFM-UGSO in the presence of steam was proposed using N 2 physisorption isotherms (BET) and scanning electron microscopy (SEM). Moreover, a sorption kinetic model for BFM-UGSO was successfully developed. Whereas both developed materials (BFM-UGSO and BFM-FA) show exceptionally high H 2 purity (96.2 % and 98.4 %, respectively) at 550 °C, BFM-UGSO exhibited a much longer pre-breakthrough time (30 vs 21 min). Interestingly, BFM-UGSO showed remarkable cyclic stability with a CO 2 sorption capacity decay of less than 1 % along the 18 carbonation-regeneration cycles. It can be mainly attributed to the uniform distribution of mixed oxides generated by the interaction of Ni and CaO with metal oxides present in UGSO during material preparation. The inert phases, e.g., MgFe 2 O 4 , Fe 2 Al 2 O 4 , NiFe 2 O 4 , and Ca 2 Fe 2 O 5 (identified by X-ray diffraction patterns (XRD)) significantly hindered the sintering of CaO particles and limited pore structure failure. During the carbonation reaction, an increase in CO 2 concentration accelerated the kinetically controlled step of the carbonation reaction. Nevertheless, CaO conversion was found to be less affected for CO 2 concentrations exceeding 30 vol %. On the other hand, the morphological changes of the BFM-UGSO at wet conditions confirmed the ability of steam to promote solid-state diffusion in the product layer through the generation of abundant highly porous structure. The results of this work offer important insights into the SESR of bio-oil and open the door for further research in the exciting field of renewable hydrogen production. [Display omitted] • Intensified sorption-enhanced steam reforming of simulated bio-oil for renewable H 2 production. • UGSO-stabilized Ni/CaO bifunctional material (BFM-UGSO) offers remarkable efficiency. • The presence of steam highly improved the BFM-UGSO sorption capacity and cyclic stability. • A sorption kinetics model of UGSO-stabilized Ni/CaO bifunctional material was developed. [ABSTRACT FROM AUTHOR]

The discovery of new environmentally friendly recyclable photosensitizers is key to develop future applications in photooxidation chemistry. We report here the evaluation of a set of differently substituted biobased hydroxyanthraquinones in the context of visible light mediated singlet oxygen (1O2) photochemistry. This class of compounds is efficiently immobilized on alumina supports, which offers a simple way of removing them from the reaction mixture downstream. An integrated process using a flow reactor with a fixed catalytic bed is also evaluated and its performance is compared with homogeneous conditions. [ABSTRACT FROM AUTHOR]

Coal gasification slag (CGS) was used for modification and loaded platinum (Pt) to liquid organic hydrogen carrier (LOHC) for the first time. The carbon hybrid silica (C/SiO 2) was prepared by removing metal oxides and carbon residue of CGS through acid treatment and calcination. The C/SiO 2 loaded Pt (Pt-C/SiO 2) exhibited only a 1.3% decrease in dehydrogenation conversion rate after 30 h of continuous catalytic dehydrogenation of methylcyclohexane (MCH), and even after 100 h, the decrease was only 4.9%. When Pt was directly loaded on CGS (Pt-CGS), it showed higher catalytic activity (dehydrogenation conversion rate was 20.4%), but lower catalytic stability (dehydrogenation conversion rate decreased by 56% after 7 h). Additionally, commercial Pt-SiO 2 catalysts exhibited poor dehydrogenation conversion rate, significantly lower than that of Pt-C/SiO 2. Density functional theory calculations confirmed the influence of carbon hybrid SiO 2 on the adsorption energy, electron transfer and density of states for the catalytic dehydrogenation of MCH. The highly active and stable Pt-C/SiO 2 catalyst can be effectively utilized for LOCH while achieving high-value utilization of CGS solid waste. [Display omitted] • Coal gasification slag was used to prepare catalyst supports with porous and weakly acidic structure. • Pt-C/SiO 2 has superior stability and adsorption compared with commercial Pt-SiO 2. • Stable operation of dehydrogenation reaction (Pt-C/SiO 2) was observed for 100 h. • Density functional theory calculations confirmed the influence of carbon hybrid SiO 2 for MCH dehydrogenation. [ABSTRACT FROM AUTHOR]

The study addresses the persistent issue of thiamphenicol (THI) accumulation in aquatic environments and its detrimental impact on biological systems. While activated carbon is commonly used for removing such organic micropollutants in advanced wastewater treatment, this research explores the innovative use of olive stones as a feedstock for activated carbon production. The novelty of this study lies in the optimization of the activated carbon preparation process using a fractional factorial design with five critical factors: concentration, heating rate, activation temperature, activation time, and impregnation ratio. By employing the methylene blue method to determine the specific surface area (SSA), the optimal conditions were identified: a phosphoric acid solid-liquid ratio of 1:2 (74.52%), a heating temperature of 550 °C at a rate of 10 °C/min, and an activation period of 120 minutes, resulting in an SSA of 53.07 m²/g. The subsequent THI adsorption tests in a fixed-bed column revealed that THI removal ef- ficiency was inversely proportional to flow rate and initial THI concentration, while positively correlated with bed height. This study fills a critical gap by demonstrating an effective, sustainable method for producing activated carbon from agricultural waste, optimizing the process parameters for maximum efficiency in micropollutant removal. [ABSTRACT FROM AUTHOR]

BACKGROUND: In pursuit of innovative wastewater treatment solutions, this study investigates the use of thermally treated palygorskite (TP) as an adsorbent to remove Escherichia coli and Enterococcus faecalis from synthetic wastewater. The goal is to explore a natural alternative to chlorine‐based disinfectants by utilizing TP's antimicrobial properties. Columns were packed with two granulometries (G1: 0.25–0.6 mm; G2: 1.40–2.36 mm) of TP and arranged in three different configurations (CA1, CA2 and CA3) to assess their bacterial removal efficiency, kinetic behavior and potential for reuse after dry heat sterilization. RESULTS: The CA3 column configuration, with its multilayer arrangement of TP, achieved the highest bacterial removal efficiency, reaching 99.1% for E. coli and 98.1% for E. faecalis. Kinetic experiments revealed that most bacterial adsorption occurred within the first 3 min, with E. coli requiring up to 10 min to reach maximum removal. TP's antibacterial effectiveness remained above 90% after two reuses. Additionally, dry heat sterilization allowed for repeated use of TP, showing stable removal efficiencies for E. faecalis and a slight decline for E. coli with each successive reuse. CONCLUSIONS: TP demonstrates significant potential as an adsorbent for wastewater disinfection, particularly in the CA3 multilayer configuration. Its rapid adsorption kinetics and resilience to heat sterilization underscore its reusability, making it a viable natural alternative to chemical disinfectants. Further research should focus on scaling this method to real wastewater treatment applications to validate its functionality in real‐world conditions. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

ABSTRACT As the world shifts towards renewable and sustainable energy sources, converting syngas into hydrocarbons using Fischer–Tropsch synthesis (FTS) catalysts is crucial. In this work, a series of copper‐modified iron‐based catalysts with cerium and strontium promoters supported on γ‐Alumina as follows were prepared using a wet‐impregnation method: FCA (18Fe/4Cu/γ‐Al2O3), FCCA (18Fe/4Cu/2Ce/γ‐Al2O3), FCSA (18Fe/4Cu/2Sr/γ‐Al2O3), and FCCSA (18Fe/4Cu/1Ce/1Sr/γ‐Al2O3). The phase, structure, and morphology of the catalysts were characterized using X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area analysis, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), inductively coupled plasma–atomic emission spectrometry (ICP‐AES), hydrogen temperature‐programmed reduction (H2‐TPR), and hydrogen temperature‐programmed desorption (H2‐TPD). The impacts of Ce and Sr, individually and in combination, on the structure, adsorption, reduction, and catalytic performance of the catalysts were evaluated in a fixed bed reactor at 300°C, 2.0‐MPa pressure, a time of stream of 168 h, and an H2/CO ratio of 1. The CO conversion and product selectivity were calculated using gas chromatography results, highlighting the synergistic effect of Ce and Sr promoters on hydrocarbon product distribution. The doubly promoted FCCSA catalyst exhibited a high CO conversion rate of 77.65%, CO2 selectivity of 43.5%, C2‐C4 selectivity of 55.89%, C5+ selectivity of 85.62.0%, and a yield of 43.19%, surpassing FCA, FCCA, and FCSA catalysts. Similar characteristics, CO conversion, and product selectivity were achieved for FCCSA during long‐term 336‐h FTS runs, indicating stability. [ABSTRACT FROM AUTHOR]

In this study, slow pyrolysis of the camelthorn plant process was conducted to produce bio-oil, biochar, and gas. The pyrolysis process was conducted between 400 and 550 °C under pressure 10 bar using a fixed bed reactor. The pyrolysis products were bio-oil, biogas, and biochar. These products were characterized using Fourier-transform infrared (FT-IR) model, gas analyzer, chromatographic analysis using GC–MS, and thermogravimetric analysis (TGA). The GC–MS results demonstrated composition of bio-oil, detecting several organic substances including levoglucosan, furan, acetic acid, phenol, and long-chain hydrocarbon. To further understand the chemical composition of bio-oil, FT-IR spectroscopy was conducted to determine functional groups. The thermal behavior and degradation of the camelthorn sample were studied using TGA which provided thermal stability and prospective applications. Gas composition was measured using a gas analyzer. These analytical methods' results offer insight on the camelthorn plant's potential as a sustainable bio-oil and biochar sources, and these findings contribute to the advancement of biomass conversion expertise and provide vital insights for sustainable energy production. [ABSTRACT FROM AUTHOR]

Acetylene hydrogenation reactions (AHR) are typically carried out in fixed bed reactors (FBRs) with high diameter‐to‐particle diameter (D/d). In this study, first, a real catalyst bed was built using the discrete element method, and the suitability of the bed was assessed using empirical equations. Second, a discrete element method‐computational fluid dynamics (DEM‐CFD) model was developed using CFD in conjunction with the reaction mechanism to simulate the AHR in the FBR and was compared with the experimental results. The results show that the DEM‐CFD can well predict the 3D interactions of velocity, temperature, and species for different D/d. The results can provide favorable theoretical guidance for the optimization of FBR and process intensification. [ABSTRACT FROM AUTHOR]

A series of Ni-W bimetallic catalysts were prepared by Ni2O3 and WO3 on porous materials and used in a fixed bed reactor for the hydrogenation of poly alpha-olefin base oil synthesis. The catalysts were characterized by N2 adsorption–desorption, XRD, H2-TPR, H2-TPD, XPS, TEM and ICP-OES to investigate the catalytic activity and explore the possible deactivation mechanism. Under the optimal reaction conditions of 250℃, 4 MPa, LHSV = 3 h−1 and H2: PAO = 200, the Ni5W1/Clay catalyst with 5% nickel and 1% tungsten loading can make the hydrogenation conversion rate as high as 100%, and the catalyst deactivation is not obvious within 8 h. The addition of W led to the reduction of the metal particle size as well as the formation of more dispersed active sites, thus improve its catalytic activity. [ABSTRACT FROM AUTHOR]

Due to growing interest in providing and storing sufficient renewable energies, energy generation from biomass is becoming increasingly important. Biomass gasification represents the process of converting biomass into hydrogen-rich syngas. A one-dimensional kinetic reactor model was developed to simulate biomass gasification processes as an alternative to cost-intensive experiments. The presented model stands out as it contains the additional value of universal use with different biomass types and a more comprehensive application due to its integration into the DWSIM process simulator. The model consists of mass and energy balances based on the kinetics of selected reactions. Two different reactor schemes are simulated: (1) a fixed bed reactor and (2) a fluidized bed reactor. The operating mode can be set as isothermal or non-isothermal. The model was programmed using Python and integrated into DWSIM. Depending on incoming mass flows (biomass, oxygen, steam), biomass type, reactor type, reactor dimensions, temperature, and pressure, the model predicts the mass flows of char, tar, hydrogen, carbon monoxide, carbon dioxide, methane, and water. Comparison with experimental data from the literature validates the results gained from our model. [ABSTRACT FROM AUTHOR]

A series of Pt/CeO 2 compounds with hollow spheres (Pt/CeO 2 –S), wires (Pt/CeO 2 –W), and particle (Pt/CeO 2 –P) morphologies were prepared and further used for catalytic liquid organic hydrogen carrier (LOHC) dehydrogenation. The exposure and distribution of different crystal faces affected the nucleation process of crystals and then formed different microscopic morphologies. Compared with Pt/CeO 2 –W and Pt/CeO 2 –P, Pt/CeO 2 –S showed hollow spherical structures with significantly higher oxygen vacancy concentrations and specific surface areas. These structural differences not only affected platinum (Pt) dispersion, but also affected the activity and stability of the catalyst, thus promoting methylcyclohexane (MCH) conversion. The fixed bed reaction showed that Pt/CeO 2 –S had excellent catalytic activity, with the MCH conversion rate at 97.7 % and hydrogen release rate of 350.50 mmol/g (Pt) /min, and it still maintained stable activity after 72 h. Under the same conditions, the MCH conversion rates for Pt/CeO 2 –W and Pt/CeO 2 –P were only 77.23 % and 32.02 %, respectively. Therefore, through the growth pattern and morphology controls of catalyst supports, this was an effective means for improving the dehydrogenation performance of LOHC. • The growth mechanism of CeO 2 hollow spheres, wires, and particles. • High catalytic activity of Pt/CeO 2 hollow spheres. • Liquid organic hydrogen carrier dehydrogenation. [ABSTRACT FROM AUTHOR]

The synergy effect of high K-low Ca-high Si biomass ash-based model system (BAMS) on the synthesis gas output and reaction characteristics of petroleum coke (PC) steam gasification process was studied using three biomass ash (BA) components, KCl, SiO2, and CaCO3, which were used as the model compounds. In the ternary model system, the steam gasification experiment of PC was conducted using a fixed bed reactor and gas phase chromatography. The synergistic effects of binary and ternary components in the ternary model system on the gasification of PC were obtained. These investigations were based on the data from the gas analysis and examined the gasification reaction process, syngas release behavior, and reaction characteristics. This study examined the effects of binary and ternary components in the ternary model system on the evolution of semi-char structure during PC gasification. This correlation revealed the synergistic effect of the model system on PC gasification. Scanning electron microscope (SEM) and Raman spectroscopy were used to characterize the structure and surface microstructure of the gasification semi-char. The results showed that the yields of different gases in the ternary model system were in H2 > CO > CO2. Compared with single PC gasification, the yields of H2, CO, syngas, and carbon conversion were increased by 29.42 mmol/g, 20.40 mmol/g, 56.68 mmol/g, and 0.35, respectively. All other components in the ternary model system with high K-low Ca-high Si demonstrated catalytic effect, except for SiO2 and the Ca-Si system, which showed inhibitory effects on syngas release and reaction features. Integrating SEM and Raman spectroscopic analyses, it was elucidated that CaCO3 and KCl diminished the degree of graphitization in semi-char through interactions with the carbonaceous matrix. This phenomenon facilitated the gasification process and exhibited a synergistic effect. Secondly, SiO2 will react with CaCO3 and KCl, producing inert silicates and inactivating these compounds, leading to the decline of catalysis. [ABSTRACT FROM AUTHOR]

Biodiesel from waste oil is produced using heterogeneous catalyzed transesterification in a fixed bed reactor (FBR). Potassium iodide/calcium oxide/alumina (KI/CaO/Al2O3) catalyst was prepared through the processes of calcination and impregnation. The novel catalyst was analyzed with X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X‐ray spectrometer (EDX). The design of experiment (DoE) method resulted in a total of 20 experimental runs. The significance of 3 reaction parameters, namely catalyst bed height, methanol to waste oil molar ratio, and residence time, and their combined impact on biodiesel yield is investigated. Both the artificial neural network (ANN) based on artificial intelligence (AI) and the Box‐Behnken design (BBD) based on response surface methodology (RSM) were utilized in order to optimize the process conditions and maximize the biodiesel production. A quadratic regression model was developed to predict biodiesel yield, with a correlation coefficient (R) value of 0.9994 for ANN model and a coefficient of determination (R2) value of 0.9986 for BBD model. The maximum amount of biodiesel that can be produced is 98.88 % when catalyst bed height is 7.87 cm, molar ratio of methanol to waste oil is 17.47 : 1, and residence time is 3.12 h. The results of this study indicate that ANN and BBD models can effectively be used to optimize and synthesize the highest %yield of biodiesel in a FBR. [ABSTRACT FROM AUTHOR]

A series of M(x)CoCeMgAlO mixed oxides with different transition metals (M = Cu, Fe, Mn, and Ni) with an M content x = 3 at. %, and another series of Fe(x)CoCeMgAlO mixed oxides with Fe contents x ranging from 1 to 9 at. % with respect to cations, while keeping constant in both cases 40 at. % Co, 10 at. % Ce and Mg/Al atomic ratio of 3 were prepared via thermal decomposition at 750 °C in air of their corresponding layered double hydroxide (LDH) precursors obtained by coprecipitation. They were tested in a fixed bed reactor for complete methane oxidation with a gas feed of 1 vol.% methane in air to evaluate their catalytic performance. The physico-structural properties of the mixed oxide samples were investigated with several techniques, such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), elemental mappings, inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction under hydrogen (H2-TPR) and nitrogen adsorption–desorption at −196 °C. XRD analysis revealed in all the samples the presence of Co3O4 crystallites together with periclase-like and CeO2 phases, with no separate M-based oxide phase. All the cations were distributed homogeneously, as suggested by EDX measurements and elemental mappings of the samples. The metal contents, determined by EDX and ICP-OES, were in accordance with the theoretical values set for the catalysts' preparation. The redox properties studied by H2-TPR, along with the surface composition determined by XPS, provided information to elucidate the catalytic combustion properties of the studied mixed oxide materials. The methane combustion tests showed that all the M-promoted CoCeMgAlO mixed oxides were more active than the M-free counterpart, the highest promoting effect being observed for Fe as the doping transition metal. The Fe(x)CoCeMgAlO mixed oxide sample, with x = 3 at. % Fe displayed the highest catalytic activity for methane combustion with a temperature corresponding to 50% methane conversion, T50, of 489 °C, which is ca. 40 °C lower than that of the unpromoted catalyst. This was attributed to its superior redox properties and lowest activation energy among the studied catalysts, likely due to a Fe–Co–Ce synergistic interaction. In addition, long-term tests of Fe(3)CoCeMgAlO mixed oxide were performed, showing good stability over 60 h on-stream. On the other hand, the addition of water vapors in the feed led to textural and structural changes in the Fe(3)CoCeMgAlO system, affecting its catalytic performance in methane complete oxidation. At the same time, the catalyst showed relatively good recovery of its catalytic activity as soon as the water vapors were removed from the feed. [ABSTRACT FROM AUTHOR]

Thermo‐catalytic co‐pyrolysis of paulownia wood and polypropylene mixture were carried out in a fixed bed horizontal reactor system. The biochar obtained from pyrolysis of paulownia wood was activated by steam at 700°C. Activated biochar supported magnesium oxide, nickel oxide and cobalt oxide catalysts were prepared by incipient miosture impregnation and were used to upgrade the bio‐oil. Catalytic pyrolysis reduced the amount of bio‐oil compared with non‐catalytic pyrolysis (59.5% of bio‐oil). The results indicate that the production of aromatic compounds increased from 40.35% to 65.93, 62.12 and 61.56% using Ni, Co and Mg catalysts, respectively. For all three catalysts, the production of furan compounds decreased. It was found that bio‐char based catalysts are suitable for use in the co‐pyrolysis process to improvement the biofuel production. [ABSTRACT FROM AUTHOR]

• The adsorption capacity of ZnFC-PA/PSF composite spheres for Cs+ was 305.38 mg/g. • Its practicability is superior than of most previously reported adsorbents. • A fixed bed reactor loaded with ZnFC-PA/PSF spheres was used for cesium removal. • The effects of operating parameters on the breakthrough curves were investigated. Radioisotope leaking from nuclear waste has become an intractable problem due to its gamma radiation and strong water solubility. In this work, a novel porous ZnFC-PA/PSF composite sphere was fabricated by immobilization of ferrocyanides modified zinc phytate into polysulfone (PSF) substrate for the treatment of Cs-contaminated water. The maximum adsorption capacity of ZnFC-PA/PSF was 305.38 mg/g, and the removal efficiency of Cs+ was reached 94.27% within 2 hr. The ZnFC-PA/PSF presented favorable stability with negligible dissolution loss of Zn2+ and Fe2+ (< 2%). The ZnFC-PA/PSF achieved high-selectivity towards Cs+ (K d = 2.24×104 mL/g) even in actual geothermal water. The adsorption mechanism was inferred to be the ion-exchange between Cs+ and K+. What's more, ZnFC-PA/PSF worked well in the fixed-bed adsorption (E = 91.92%), indicating the application potential for the hazardous Cs+ removal from wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

This study examined the desulfurization capacity of a high specific surface area activated carbon (AC) and its modifications for real diesel fuel of different sulfur concentrations. Adsorbent's evaluation strategy included desulfurization experiments under batch and continuous conditions. Batch experiments were conducted by a homogeneous stirring of adsorbent and diesel fuel, while for the continuous tests, a fixed bed reactor was used to generate breakthrough desulfurization curves. In the fixed bed reactor's tests, the sulfur removal – considering an initial concentration of about 6 parts per million weight (ppmw) – was substantial for the first 30 ml fuel per gram of adsorbent. For this specific quantity, the total sulfur content of the cumulatively processed fuel was less than 2 ppmw. The batch experimental results are elaborated using a mechanistic kinetic model for batch adsorption considering the total sulfur mass balance. Mass transfer coefficients are derived this way for all the conditions and adsorbents tested. The adsorption equilibrium data from batch experiments are utilized to model the fixed bed experimental results. In this way, mass transfer coefficients for the fixed bed are derived. In any case, the modeling results indicate that sulfur is not the only adsorbate of the process, but other adsorbates act competitively to sulfur, thereby complicating the process. [ABSTRACT FROM AUTHOR]

To achieve optimal performance, anaerobic digestion (AD) requires well-balanced operation conditions, steady physical–chemical conditions, and adequate nutrient concentrations. The use of anaerobic structured-bed reactor (ASTBR) presents these conditions. However, several additional investigations are required to elucidate robustness to treat domestic sewage (DS). This pioneering study investigated the performance of an ASTBR in treating DS across four decreasing hydraulic retention times (HRTs) (12, 8, 6, and 5 h). The study aimed to assess organic matter removal, the influence on physical–chemical parameters, and the monitoring of trace metals (TMs) during long-term operation (614 days). Overall, the results underscore the viability of employing ASTBR for DS treatment, achieving an average chemical oxygen demand (COD) removal efficiency of 70%. The system demonstrated consistent long-term operation over 614 days, maintaining stability even with decreasing hydraulic retention times (HRTs). The average effluent concentration of volatile fatty acids (VFAs) was 20.4 ± 3.3 mg L−1, with a pH value averaging 7.2 ± 0.1. TM concentrations at an HRT of 12 h exhibited higher levels in the effluent compared to the influent, gradually decreasing over the course of operation and ultimately stabilizing at levels similar to those observed in the influent. The concentrations of metals, including Ba, Cr, Fe, Mn, Ni, Pb, Se, and Zn, monitored in the effluent samples adhered to the allowable discharge thresholds as stipulated by Brazilian regulations. [ABSTRACT FROM AUTHOR]

There is an increasing attention for using compost in remediation of heavy metals, textile dyes and emerging contaminants. In this work, the competitive uptake of two weakly interacting dyes, Direct Blue 71 and Direct Blue 151, by compost is examined. The optimum uptake of both dyes in single and bi-solute systems is achieved at pH 3.0, 240 min equilibrium time, 25 °C, and a relatively high compost dose 3.0 g L−1. Using Langmuir model, the maximum individual uptake of dyes by compost is 117.5 and 102.5 mg g−1 for DB151 and DB71, respectively. These values, estimated from their single-solute solution, were used to assess their overall competition under batch and fixed bed conditions. Under batch conditions, both dyes are removed from bi-solute solutions with higher competition for DB151 against DB71. The estimated competitive factors were 0.70 and 0.80 for DB71 and DB151, respectively. With a combined uptake capacity of 162 mg g−1 for both dyes, the performance of compost is promising. The fixed bed uptake of dyes indicated 80% utilization of compost capacity for single-solute solutions, at bed-depth 20 cm, flow rate 10 mL min−1 and inlet concentration 150 mg L−1. However, dyes adsorption under dynamic conditions is making only 40 and 60% of the maximum capacity of DB71 and DB151, respectively. The incomplete utilization is attributed to the fact that dynamic conditions are not as favorable to reach equilibrium as the batch process. The relative efficacy factor rexp was then used to select the optimum treatment process. From single and bi-solute solutions, dyes are effectively removed by fixed bed adsorption as rexp < 1.0, however, batch process is recommended to remove DB71 in the presence of DB151 as rexp > 1.0. [ABSTRACT FROM AUTHOR]

N-Substituted 5-(hydroxymethyl)-2-furfuryl amines have been obtained through the reductive amination of 5-hydroxymethylfurfural (HMF) with a variety of primary amines using a non-noble metal catalyst based on monodisperse Co nanoparticles covered by a thin carbon layer. The Co@C catalyst was highly active, selective and stable, allowing us to perform the reductive amination of HMF under very mild reaction conditions (60 °C and 4 bar H2) using ethanol as a green solvent and achieve the corresponding amino-alcohol in yields ranging from 80 to 99%. Moreover, the reaction was extended to other furanic aldehydes with excellent success. Furthermore, in order to synthesize amino-ester derivatives, precursors of ammonium salt-based surfactants, the reductive amination of HMF with methylamine was coupled with the selective esterification of the hydroxymethyl group of the furan ring with fatty acids using lipase CALB (Novozym 435) as a biocatalyst in 2-methyltetrahydrofuran as a green and enzyme compatible solvent, achieving practically total conversion to the corresponding amino-esters. The process was implemented in flow reactors by combining two consecutive fixed bed reactors, achieving a global yield of the amino-ester derivative of 85%, which was maintained over 86 h of operation. [ABSTRACT FROM AUTHOR]

Coal is the most valuable gasification resource due to its abundance and low cost for commercial applications. But utilization of low-rank Indian coals for gasification is challenging due to difficulty in washing. For utilizing low-grade high ash raw coal, blending is one of the effective methods to control the gasification performances. So, the present study explores the gasification of such a low-rank raw coal blend and compares the results with washed coal blend. The blending effects on raw gas yield (kg/kg of coal) and heating value (Kcal/Nm3) were investigated for coal blends-WH (washed coal with high-rank coal) and RH (raw coal with high-rank coal). In WH, raw gas yield is 1.210 to 1.225 (kg/kg of coal), whereas, in RH is 1.189 to 1.213 (kg/kg of coal), though the fixed carbon content of WH (40.75–41.74%) is lower than RH (44.73–45.25%). In washed coal, raw gas yield is minimum (0.75 kg/kg of coal). The heating value is lower in WH (2730–2871 Kcal/Nm3) than in RH (2884–2978 Kcal/Nm3). Statistical correlation is developed between gaseous components of raw gas and heating value; H2/CO ratio is the most significant parameter. RH gasification is economically viable than WH. [ABSTRACT FROM AUTHOR]

Transformation of methyl lactate to acrylic acid was investigated over Ca3(PO4)2, Ca2(P2O7) and their mixture in the temperature range of 250-425 °C. The initial concentration of methyl lactate in water was varied from 2 wt% to neat methyl lactate. The results showed that these phosphate catalysts did not contain any measurable amounts of either acid sites or basic sites. The best catalyst was Ca3(PO4)2 giving 62% selectivity to acrylic acid at 75% conversion at 400 °C using GHSV of 95280 h−1 and 2 wt% methyl lactate in the initial feed. This catalyst exhibited larger surface area in comparison to Ca2(P2O7). Elemental analysis revealed that some Ca leaching occurred during reaction, while in case of Ca2(P2O7) the calcium leaching was 3.4 fold higher than observed for Ca3(PO4)2. Long-term results over Ca3(PO4)2 showed that extensive catalyst deactivation occurred during the first 11 h time-on-stream, after which the activity dropped only slightly. In addition to kinetic studies with different parameters, also, kinetic modeling was performed and the activation energies for formation of different products were determined over different catalysts. [ABSTRACT FROM AUTHOR]

Agricultural residue is an important biomass resource in China. Utilization of agricultural residue for production of high-quality fuel oil is an attractive and challenging topic towards the goals of “Carbon Peaking and Carbon Neutrality”. Biomass hydropyrolysis integrated with volatile catalytic hydrogenation is a new process that can efficiently improve the yield and quality of bio-oil. This work is purposed to explore this new biomass conversion technology by laboratory experiments using a tandem pressurized fixed bed reactor. A bimetallic molecular sieve catalyst (NiMo-HZSM-5) was prepared by an impregnation method and used for catalytic hydrogenation. Biomass was hydropyrolyzed under a condition of 5 MPa H2 pressure, 15℃/min heating rate and 700℃ final temperature to generate volatile matter, which was online hydrogenated through the NiMo-HZSM-5 catalyst bed under a condition of 5 MPa H2 pressure, 320℃ reaction temperature and 26 s residence time (corresponding to space velocity of 112.5 h−1 ). The paper firstly presents the oil production results of three types of agricultural residue, corn stalk, cotton stalk and peanut straw by the catalytic hydrogenetion. The paper is then devoted to further clarifying the conversion characteristics of different biomass fiber constituents by means of the water washing and acid washing pretreatments of three agricultural residues as well as by adopting cellulose and lignin as model compounds. Results showed that in the case of non-catalytic hydrogenation, all of the bio-oils obtained from three agricultural residues contained oxygenates and aromatic hydrocarbons as two main classes of compounds, and that from peanut straw also contained a high proportion of nitrogenous compounds. In contrast, all of the bio-oils derived from three agricultural residues by the catalytic hydrogenation (CH bio-oils) contained almost neither oxygenates nor nitrogenous compounds. The yields of CH bio-oils reached 10.3%–15.9% for three agricultural residues. The CH-bio-oils were composed of 73.0–84.8% saturated aliphatic hydrocarbons (mainly cyclopentanes, cyclohexanes, and perhydro- naphthalenes), 6.1%–13.1% partially hydrogenated aromatic hydrocarbons (mainly di-, tetra-hydronaphthalenes) and a small amount of monocyclic aromatic hydrocarbons. The result highlights that the two-stage process of hydrogenation pyrolysis integrated with NiMo-HZSM-5 catalytic hydrogenation can effectively convert agricultural residue into a kind of high-quality bio-oil composed mainly of alicyclic hydrocarbons. The water washing could remove about half of neutral extractives from each of three agricultural resides. After the water washing, three agricultural residues showed increases in the yields of CH bio-oil to 18.1%–18.5%, suggesting that neutral extractives are less conducive to the production of CH bio-oil compared to other fiber components. The acid washing enabled cellulose and lignin to be left in the agricultural residues as main components. Via this pretreatment, the yields of CH bio-oil increased to 18.2%–22.5% for three agricultural residues, with cotton stalk having the highest yield. The yields of typical aliphatic hydrocarbon compounds (methyl-cyclopentane, methyl-cyclohexane and decahydro-naphthalene) from all three agricultural residues were increased by the acid washing. The study using model compounds revealed that cellulose is a fiber for not only achieving a high yield of CH bio-oil but also selectively producing aliphatic hydrocarbon compounds such as cyclopentane, cyclohexane, and decahydro-naphthalene. Meanwhile, lignin has a lower yield of bio-oil, and it tends to produce monocyclic aromatic hydrocarbons. Lignin can also generate cyclohexane compounds and partially hydrogenated polycyclic aromatic hydrocarbons, but it has a low propensity to the formation of cyclopentane compounds. This study has provided a new technical route to utilizing agricultural residues for high-efficient production of fuel oil. [ABSTRACT FROM AUTHOR]

Using deactivated methanol to olefin (MTO) catalyst as a partial aluminum and phosphorus source and entire silicon source, and triethylamine as a template, a directing agent was prepared at low temperature (160 °C). S-SAPO-34 molecular sieve was then green synthesized by directing agent method, and C-SAPO-34 molecular sieve was synthesized without directing agents. The crystal structures, morphologies, pore structures, acidic characteristics, coordination states and thermal stabilities of the two molecular sieves were analyzed by XRD, SEM, N2 adsorption/desorption, NH3-TPD, solid-state MAS-NMR and TGA. The results indicate that SAPO-34 molecular sieve with high crystallinity can be synthesized by directing agent method under the condition of reducing the amount of organic template agent by 2/3. The catalytic performance evaluation of S-SAPO-34 and C-SAPO-34 molecular sieves for MTO reaction was carried out on a fixed bed reactor under the reaction conditions of temperature 460 °C, atmospheric pressure, methanol mass space velocity 6.0 h-1 and pure methanol as the raw material. The results show that compared to C-SAPO-34, the crystallization performance of S-SAPO-34 molecular sieve is much better, with a relative crystallinity of 136%, and the crystal morphology is more complete. In MTO reaction, S-SAPO-34 and C-SAPO-34 molecular sieves can ensure methanol conversion, and the highest selectivities of diene (ethylene + propylene) are 82.1% and 82.3%, respectively. This method can provide a new idea for the green synthesis of SAPO-34 molecular sieve under low dosage template conditions. [ABSTRACT FROM AUTHOR]

The integrated CO2 capture and utilization coupled with the reverse water-gas shift reaction (ICCU-RWGS) presents an alternative pathway for converting captured CO2 into CO in situ. This study investigates the effectiveness of three calcium-based materials (natural limestone, sol-gel CaCO3, and commercial CaCO3) as dual-functional materials (DFMs) for the ICCU-RWGS process at intermediate temperatures (650–750 °C). Our approach involves a fixed-bed reactor coupled with mass spectrometry and in situ Fourier transform infrared (FTIR) measurements to examine cyclic CO2 capture behavior, detailed physical and chemical properties, and morphology. The in situ FTIR results revealed the dominance of the RWGS route and exhibited self-catalytic activity across all calcium-based materials. Particularly, the natural limestone demonstrated a CO yield of 12.7 mmol g−1 with 100% CO selectivity and 81% CO2 conversion. Over the 20th cycle, a decrease in CO2 capture capacity was observed: sol-gel CaCO3, natural limestone, and commercial CaCO3 showed reductions of 44%, 61%, and 59%, respectively. This suggests inevitable deactivation during cyclic reactions in the ICCU-RWGS process, while the skeleton structure effectively prevents agglomeration in Ca-based materials, particularly in sol-gel CaCO3. These insights, coupled with the cost-effectiveness of CaO-alone DFMs, offer promising avenues for efficient and economically viable ICCU-RWGS processes. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company 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 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]

This study aims to investigate the effects of different catalysts on biomass gasification. Therefore, red mud (RM) and Aluminum–Nickel alloy were used as catalysts with biomass mixture (BM) for the lab-scale gasification studies by using an updraft and a modifiable-downdraft fixed bed reactor. The maximum volumetric percentage of H 2 , ranging from 51% to 65%, was achieved at 900 °C in both gasifiers. Al–Ni catalyst significantly boosted H 2 content, reaching 65% in the updraft gasifier at 900 °C with 0.05 L/min dry air. H 2 /CO ratio varied from 2 to 4 for BM, while catalyst use expanded the range to 1.6–7 with the Al–Ni catalyst demonstrating the most effective performance. In general, it was seen that RM increased the H 2 component in the syngas between 1 and 7 vol% at 900 °C in updraft gasifier. In the modifiable-downdraft reactor, on the contrary, H 2 concentration in the syngas decreased by 2–6% with the addition of RM. [Display omitted] • Red mud and aluminum - nickel alloy were added to biomass as catalysts. • Two different fixed-bed gasifiers were operated under the same conditions. • The use of the catalyst increased the H 2 vol% in the syngas. • The max. volumetric percentage of H 2 gas was found to be in the range of 51–65%. [ABSTRACT FROM AUTHOR]

The development of catalytic methods for xylose transformation as renewable raw material into value-added chemicals such as lactic and glycolic acid esters has been the subject of intensive research in recent years. Thus, methyl lactate and methyl glycolate are used as a starting material for the production of lactide and glycolide – an important monomers for the production of biodegradable polymers. The aim of this work was to search of simple effective catalyst for transformation of xylose into methyl esters of lactic and glycolic acids. For this purpose, tin-containing alumina doped with СeO2, MoO3 and CuO oxides were synthesized by impregnation method. Textural and structural parameters of obtained МeO‑SnO2/Al2O3 mixed oxides were estimated from the results of low-temperature adsorption-desorption of nitrogen and X-ray diffraction. The formation of morphology ceria close to octahedra for CeО2‑SnO2/Al2O3 sample is confirmed by the X-ray phase analysis data and SEM microphotographs. The UV spectroscopy data indicates the nanosize of tin dioxide particles on the γ‑Al2O3 surface. According to the titration results, CeО2‑SnO2/Al2O3 is acid mixed oxide with H0 ≤ –3.0. The catalytic conversion of xylose solution in methanol was carried out in rotated autoclaves and in a flow stainless steel reactor with a fixed bed of catalyst. The products of the target reaction C5H10O5+2CH3OH+1/2O2 = C4H8O3+C3H6O3+2H2O were analyzed by 13C NMR. It was found that a complete conversion of 4 % xylose solution in a 70 % aqueous methanol solution occurs with the formation of methyl lactate (42 %) and methyl glycolate (24 %) on the developed CeO2-SnO2/Al2O3 catalyst loading of 3.5 mmol C5H10O5/gcat/h at 190 °C/3.0 MPa in air flow. The path of the reaction is proposed, namely: the IVSn4+ ions in           CeO2-SnO2/Al2O3 catalyst as Lewis acid sites promote retro-aldol xylose condensation and further Cannizzaro rearrangement of intermediate methyl pyruval hemiacetal into methyl lactate. And CeO2 provides selective oxidation of glycol aldehyde formed as a result of aldol decondensation of xylose to methyl glycolate. [ABSTRACT FROM AUTHOR]

Biogas dry reforming or dry reforming of methane (DRM) is an alternative to produce hydrogen, in the context of development of sustainable routes for energy production, since this route uses CH 4 and CO 2 , two greenhouse gases as reactants. However, the deactivation of catalysts due to carbon deposition and sintering is the main drawback of this reaction. In this work, with the aim of minimizing carbon formation and sintering during DRM, the effect of lithium as a promoter in catalysts Ni–Al derived from layered double hydroxides was investigated. The catalysts were prepared by co-precipitation and characterized by different techniques: BET surface area (S BET), X-ray diffraction (XRD), temperature-programmed reduction (TPR), CO 2 and H 2 temperature-programmed desorption (CO 2 -TPD and H 2 -TPD), Scanning Electron Microscopy (SEM-EDS), temperature-programmed oxidation (TPO). The catalytic tests were carried out in a fixed bed reactor using a synthetic biogas (60% CH 4 and 40% CO 2) in the temperature range of 500–750 °C. The incorporation of Li into the Ni–Al-LDH changed the reducibility and basicity of the catalysts. The Li2 sample containing an intermediary amount of Li (5 wt%) showed the highest reduction temperature and highest density of basic sites, which resulted in the smallest Ni crystallite size before and after the reactions. As a result, this catalyst presented the greater resistance to sintering and a lower rate of carbon produced. For the reaction carried out at 700 °C, only the Li2 catalyst remaining active during the test and reaching a maximum of 80% and a final CH 4 conversion of 54% after 480 min of reaction, whereas CO 2 conversion was higher than 90%. All other samples deactivated at different rates due to carbon deposition and sintering. [Display omitted] • Li–Ni–Al LDH-derived catalysts were successfully prepared by coprecipitation. • The introduction of Li changes the reducibility and the basicity of Ni–Al. • Sample with 5 wt% Li showed the smallest crystallite size and the highest basicity. • Sample with 5 wt% Li showed the highest sintering resistance and the lowest carbon rate. • Catalyst with 5 wt% Li was the only one that maintained activity with time-on-stream at 700 °C. [ABSTRACT FROM AUTHOR]

The decontamination of wastewater is an important issue for the nuclear industry. The removal of Sr2+, one of the most problematic radioelements, requires hierarchical materials suitable for fixed-bed processes. This article describes a patented emulsion-templating route for the synthesis of Linde Type A (LTA) zeolite-geopolymer composites with a multiscale porosity. By dispersing zeolite particles in an emulsion oil-in-water containing precursors of geopolymer, LTA zeolite–geopolymer composites can be obtained after curing and eliminating the oil phase. The zeolite particles alter the macroporous structure of the materials (replicating the oil droplets) as well as the size of the mesopores of the geopolymer binder. Moreover, zeolite contents higher than 30 wt% induce a crumbling of the material structure. The presence of LTA zeolite particles increases the selectivity of the composites for Sr2+ in very saline media, while the porous network of the material ensures rapid adsorption. The optimal composite prepared here outperformed a commercial sorbent for the Sr2+ decontamination of a saline wastewater through a packed column. • Geopolymer-zeolite composites were synthesized through an emulsion-templating route. • The zeolite weight percentage in the composite strongly influences its microstructure. • Increasing the amount of zeolite in the material increases its selectivity for Sr2+. • Geopolymer-zeolite composites are well adapted to be used in fixed bed process. [ABSTRACT FROM AUTHOR]

Mo2C/AC-x converters were prepared using nitric acid pretreated activated carbon (AC) as a carrier, with x representing the carbonization time. The performance of the converter in converting NO2 to NO was evaluated in a fixed bed reactor. The Mo2C/AC-x converters were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 physisorption and desorption, H2 programmed temperature reduction (H2-TPR) and NO2 temperature-programmed desorption–mass spectrometry (NO2 TPD-MS). The NO2 to NO conversion rate decreases in the following order: Mo2C/AC-4 > Mo2C/AC-2 > Mo2C/AC-6 > Mo2C/AC-0.5. Short carbonization times, like 0.5 h, led to incomplete carbonization of MoO2 to β-Mo2C. Conversely, long carbonization times, like 6 h, resulted in the formation of carbon deposits that can block pores or cover active sites, leading to decreased catalytic performance. Mo2C/AC-4 has the highest specific surface area and pore volume. The NO2 conversion rate of Mo2C/AC-4 reached 98.9% at 150°C, demonstrating direct efficient conversion of NO2 to NO at a lower temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] The provision of green hydrogen on an industrial scale is one of the challenges for a successful CO 2 -neutral energy transition. Sintering is still the bottleneck for the use of iron-based oxygen carriers for efficient hydrogen production and storing performance in chemical looping in a large-scale system. In this work, we demonstrate an effective way for hydrogen production by the synthesis of structured oxygen carriers (OC) from cost efficient, green and environment-friendly materials. The novel structured oxygen carriers with a core–shell architecture show an innovative concept to prevent the agglomeration of pellets in the fixed bed reactor system. The environment-friendly iron-based material maintained an oxygen exchange capacity of over 80 % for 100 cycles. The pore network of the catalytic system was preserved by incorporating a structure with separate compartments. A synergistic effect between the sintering, especially of the porous network, and the gas transport was revealed. In addition, an undiscovered leach-out effect of the OC system on the Al 2 O 3 support material, which is associated with a deactivation phenomenon, was also revealed. The work provides fundamental new insights for understanding the phenomena that occur during the sintering process in the OC material and the influence on the lifetime of the chemical looping process. Finally, we present that the structured OC exhibits excellent performance and provides a new approach in material design for successful implementation in high temperature catalytic fixed bed system for long term operation. [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.)

Transient responses of reaction–desorption process were predicted from mathematical solutions of modeling equations for CSTR (continuously stirred tank reactor) containing core–shell adsorbent particles. Analytical solutions on the core–shell particles were derived for core–shell spherical, cylindrical, and slab-type morphologies, assuming inert-cores. Unlike continuous adsorber, CSTRs for reaction–desorption process containing spherical particles exhibited the slowest reduction rate of concentration of adsorbate, because the amount of adsorbed component on the particles is the largest among three kinds of particle shapes. Factors affecting the transient concentration in bulk medium of reaction–desorption process were investigated by adjusting inert-core thickness, inlet flow rate, initial concentration of reactant in inflow stream, amount of adsorbent, and Thiele modulus. Concentration profile inside the particles as well as average intra-particle concentration could be also predicted for comparison with bulk concentration of CSTR. For non-linear isotherm and non-linear reaction kinetics, concentration of active component could be predicted by solving non-linear coupled differential equation using finite element method. For connected CSTRs in series, systems of reaction-diffusion equations were solved by finite element method to study the effect of number of connected reactors. When the number of reactors was sufficiently large, the reactor system could be approximated to fixed bed reactor for reaction–desorption process. [ABSTRACT FROM AUTHOR]

The treatment of oily sludge by pyrolysis has the advantage of efficient recovery of pyrolysis tar, and it is an effective way to dispose oily sludge in a harmless and resourceful way. The high content of iron and calcium inorganic substances in oilfield sludge should not be neglected on the distribution of pyrolysis products and the removal of petroleum hydrocarbons. In this paper, the effects of iron and calcium oxides on the pyrolysis characteristics of oily sludge were investigated by using a fixed bed pyrolysis reactor to achieve the resourceful and harmless disposal of oily sludge, leading to the highest yield of liquid (15.97% and 17.60%) at 500 °C and the highest yield of gas (6.21% and 7.41%) at 700 °C pyrolysis of oily sludge. The addition of Fe2O3 not only increased CO and CO2 in the pyrolysis gas above 500 °C, but also increased the content of aromatic hydrocarbons in the pyrolysis tar. The presence of CaO not only promoted the formation of long-chain hydrocarbons in the pyrolysis tar, but also increased the percentage of H2, CH4 and C2H4 in the pyrolysis gas. By adding of Fe2O3 and CaO of 10% respectively at 500 °C, the content of petroleum hydrocarbons in the pyrolysis residue decreased to 1.87% and 1.94%, respectively. [ABSTRACT FROM AUTHOR]

A response surface methodology (RSM) with 3 levels and 4 variables was used to model and optimize the n-heptane isomerization kinetic process over Pt-HZSM-5/HMS catalysts in a fixed bed micro reactor. 30 sets of isomerization rate tests were performed at different conditions of H2 flow rate (20-45 ccmin−1), n-heptane flow rate (2-4.5 cch−1), the temperatures (200-350 °C), and the weight percent of HZSM-5 (10-40%). It was observed that the amounts of HZSM-5 into Pt-HMS structure has the greatest effect on the rate of reaction. The surface and contour plots confirm that the rates do not considerably change versus temperature, n-heptane and H2 flow rates. 0.24 molg−1s−1 is the highest reaction rate obtained in the 4.5 cch−1 n-heptane and 45 cc min−1 H2 flow rate. The RSM was effective for predicting and optimizing this process. The modelling results also show both power-law and Langmuir–Hinshelwood models are in agreement with the experimental data. [ABSTRACT FROM AUTHOR]

A series of SO42−/TiO2 solid superacid catalysts were prepared under different conditions. The effect of different preparation conditions on the SO42−/TiO2 catalyst was investigated by evaluating the change of its crystallinity, chemical structure and acid content. The catalytic performance of the SO42−/TiO2 catalyst was evaluated by α-pinene isomerization in a continuous fixed bed reactor. When ammonia was used as the precipitation agent, the concentration of sulfuric acid impregnation solution was 2 M, and the calcination temperature was 500 °C, the activity of the SO42−/TiO2 catalyst reached the maximum, the conversion rate of α-pinene was stable at about 95%, and the selectivity of camphene reached 40%. It was found that the structure and textural properties of the SO42−/TiO2 catalyst did not change significantly after regeneration by studying the regeneration performance of the SO42−/TiO2 catalyst. [ABSTRACT FROM AUTHOR]

Energy demand is rising over time in both developing and developed countries. Therefore, finding new sources of energy is a prime concern now. For this effort, this paper presents the pyrolysis of onion (Allium cepa) shells in a reactor with a fixed bed for generating alternative liquid fuel. This paper also compares alternative fuel characteristics, including higher heating value, viscosity, density, pour point, and flash point, with conventional petroleum fuels at optimal process conditions. The work adopted pyrolysis to produce liquid fuel at a temperature range of 400–550 °C and utilized LPG to provide a heat source. The liquid product (fuel oil) was collected, and non-condensable gas was flared. The liquid product was tested for various properties, and the results of the analyses show that alternative fuel has a higher heating value of 12.227 MJ/kg, density of 800 kg/m3, viscosity of 4.3 cP at 30 °C, pour point below −6.2 °C, and flash point around 137 °C, with a variation due to the volatile matters. To obtain favorable conditions for pyrolysis, some parameters, including bed temperature, sample quantity, average particle size, and operating time, were varied and analyzed. The physio-chemical properties made the alternative fuels isolated from conventional petroleum fuels due to the variation in distillation temperature. This work shows that the fuel oil generated from the pyrolysis of onion shells could be considered an alternative source of fuel. [ABSTRACT FROM AUTHOR]

The selective hydrogenation of 5‐(hydroxymethyl)furfural (HMF) into 2,5‐bis‐(hydroxymethyl)tetrahydrofuran (BHMTHF) in flow reactor using water as a green solvent, has been achieved on a non‐noble metal catalyst based on monodispersed CoNi alloy nanoparticles covered by a thin carbon layer. The alloyed catalyst containing CoNi (molar ratio 1 : 1) was prepared in a one‐step synthesis following a hydrothermal method. Total conversion of HMF with 91 % selectivity to BHMTHF was achieved. The reaction network has been stablished, in which the carbonyl group of HMF is first reduced to alcohol giving the 2,5‐bis‐(hydroxymethyl)furan (BHMF) with an apparent activation energy of 25 KJ/mol, and then the double bonds of the furan ring are hydrogenated (apparent Ea=31 KJ/mol). Formation of byproducts, mainly proceed from furan ring opening and ring rearrangement processes of BHMF, promoted by water. BHMTHF resulted a compound highly stable under reaction conditions. The fixed bed flow reactor was maintained operational for 65 h without observing any loss of catalytic activity and selectivity. [ABSTRACT FROM AUTHOR]

Hollow carbon nanospheres (HCNS) were prepared from carbon black (CB) derived from spent tyre pyrolysis oil. The pristine CB produced by partial oxidation of the pyrolysis oil in a drop tube furnace was subsequently oxidised in air in a fixed bed reactor to yield HCNS. The effect of oxidation temperature (300 to 700°C) and time (1 to 8 h) on the burn‐off (Bt) of the sample over the duration (t) of oxidation and average reaction rate (Rt) was assessed. The BET surface area and pore volume and the nanostructure of the HCNS samples obtained were characterised using N2 adsorption–desorption and high‐resolution transmission electron microscope (HRTEM) techniques, respectively. Higher temperature and longer oxidation time led to higher Bt. As Bt increased, the BET surface area and pore volume initially increased linearly due to the removal of the amorphous core and then decreased because of the collapse of the shell of the carbon nanostructure. At Bt of ~56%, the maximum BET surface area and pore volume of the HCNS were 383.2 m2 g−1 and 0.39 cm3 g−1, respectively, compared to ~19.5 m2 g−1 and 0.033 cm3 g−1 of the pristine CB. The HRTEM images indicate that the change in BET surface area corresponds to the formation of the HCNS, as the core of the CB particle was preferentially consumed to create a hollow structure. The formation of HCNS follows an internal oxidation model, which is characterised by rapid core consumption and relatively slow shell consumption. [ABSTRACT FROM AUTHOR]

This paper introduces a novel process for decomposing N2O through interstage cooling utilizing a heat pipe heat exchanger. The reactor design involves segmenting the fixed bed reactor into multiple layers and integrating heat pipe heat exchangers between these layers to efficiently dissipate the high heat generated by the upper fixed bed reactor. This innovative approach facilitates the direct decomposition of N2O feedgas with high concentrations, obviating the need for gas dilution. The study conducted in this paper employed Fluent and ASPEN PLUS to investigate N2O decomposition with interstage cooling using heat pipe heat exchangers, as well as decomposition after dilution. A comparison between the two methods was made based on catalyst dosage, temperature uniformity, and reactor energy consumption. The results demonstrate that the proposed method for N2O decomposition via interstage cooling with a heat pipe heat exchanger is a viable option, offering the desired temperature control and enhanced efficiency. Furthermore, this reactor design effectively reduces both catalyst usage and energy consumption, providing substantial advantages over traditional approaches. [ABSTRACT FROM AUTHOR]

Microbubble shows great potential for hydrogenation reaction in fixed bed reactors (FBRs). However, the lack of understanding of the hydrodynamic behaviors of microbubble swarm in FBR limits the reactor design. In this work, a pilot‐scale HiGee‐aided fixed bed reactor (HFBR), including a HiGee microbubble generator (HMG) and a catalyst bed, has been developed and then applied for poly alpha olefin 4 (PAO 4) hydrogenation. An empirical correlation of Sauter mean diameter (d32) of microbubbles at the inlet and outlet of catalyst bed was established. The gas holdup (φb) of catalyst bed with HMG was 5–10 times higher than that without HMG. Based on d32 and φb, the effective interfacial area in HFBR was calculated as 2000–6000 m2/m3. Compared with static mixer‐aided fixed bed reactor, the aromatic content of PAO 4 hydrogenated in the HFBR was 56%–69% lower, which shows bright future for industrial application. [ABSTRACT FROM AUTHOR]