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To solve the problems of low gasification efficiency and high tar content caused by solid–solid contact between biomass and oxygen carrier in traditional biomass chemical looping gasification process. The decoupling strategy was adopted to decouple the biomass gasification process, and the composite oxygen carrier was prepared by embedding Fe2O3 in molecular sieve SBA-16 for the chemical looping reforming process of pyrolysis micromolecular model compound methane, which was expected to realize the directional reforming of pyrolysis volatiles to prepare hydrogen-rich syngas. Thermodynamic analysis of the reaction system was carried out based on the Gibbs free energy minimization method, and the reforming performance was evaluated by a fixed bed reactor, and the kinetic parameters were solved based on the gas–solid reaction model. Thermodynamic analysis verified the feasibility of the reaction and provided theoretical guidance for experimental design. The experimental results showed that the reaction performance of Fe2O3@SBA-16 was compared with that of pure Fe2O3 and Fe2O3@SBA-15, and the syngas yield was increased by 55.3% and 20.7% respectively, and it had good cycle stability. Kinetic analysis showed that the kinetic model changed from three-dimensional diffusion to first-order reaction with the increase of temperature. The activation energy was 192.79 kJ/mol by fitting. This paper provides basic data for the directional preparation of hydrogen-rich syngas from biomass and the design of oxygen carriers for pyrolysis of all-component chemical looping reforming. [ABSTRACT FROM AUTHOR]

This work presents a multi-functional NiCoCe-based catalyst for crude oil steam reforming for hydrogen production. Arab Light (AL) and Arab Extra Light (AXL) were centrifuged to reduce the asphaltenes and sequentially steam reformed in a fixed bed reactor. Results showed that the NiCoCe catalyst was stable and highly selective under reaction conditions and in cyclic operation. The physicochemical properties of the catalyst were determined via inductively coupled plasma–optical emission spectrometry, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The high dispersion of the NiCo alloy on a Mg–Al support was crucial for ensuring the hydrocarbon reforming in the presence of heteroatomic species. • Multi-functional NiCoCe-based catalyst for crude oil to hydrogen. • Process based on steam reforming of different Arabian crudes. • Arabian light and Arabian extra light are centrifuged to reduce the asphaltenes. • The cyclic operation helped to sustain the catalyst activity and stability. • Continued hydrogen production for 14 h. [ABSTRACT FROM AUTHOR]

The incredible potential of metal oxide-based two-step solar-driven thermochemical water splitting technology lies in its ability to harness limitless solar energy to produce clean and renewable hydrogen fuel. However, achieving high redox kinetics and lowering the reaction temperature remain the primary challenges in hydrogen production. The CeO 2 –ZrO 2 system is a well-known oxygen carrier for thermochemical water splitting on account of its high temperature stability, quick kinetics, and redox cyclability. While recent studies have explored the combination of methane partial oxidation with metal oxide reduction, the reduction effect of cerium-zirconium oxide is relatively low, and reactivity still needs improvement. The nickel-doped system exhibits good redox performance and is regenerative. In this study, different mass percentages nickel-loaded oxygen carriers mNi/Ce 0.8 Zr 0.2 O 2 (m = 0, 1, 3, 5, 7, 9) were prepared using the impregnation method. Redox properties of oxygen carriers were investigated in a fixed bed reactor and various characterizations were performed. To assess the durability of mNi/Ce 0.8 Zr 0.2 O 2 , 60 long-cycle experiments were also conducted. The results indicate that the lattice oxygen in mNi/Ce 0.8 Zr 0.2 O 2 exhibits remarkable selectivity for the partial oxidation of CH 4 at temperatures ranging from 880 to 925 °C. The best reactivity performance was achieved with a nickel loading ratio of 5 wt%, and after 60 consecutive redox cycles, 5Ni/Ce 0.8 Zr 0.2 O 2 demonstrates remarkable robustness, maintaining its redox activity. • mNi/Ce 0.8 Zr 0.2 O 2 demonstrates excellent redox reactivity at 900 °C. • Introduction of Ni loading leads to an increase of 60% in fuel generation. • Reduction time of 5Ni/Ce 0.8 Zr 0.2 O 2 is reduced by 32% compared to Ce 0.8 Zr 0.2 O 2. • 5Ni/Ce 0.8 Zr 0.2 O 2 exhibited the most superior redox activity. [ABSTRACT FROM AUTHOR]

MnO2 based photothermal catalysis has been demonstrated to be a promising technology to eliminate pollutants in air. However, the relationship between catalytic activity and MnO2 crystal phase has not been revealed. Herein, we hydrothermally synthesized four MnO2 catalysts, α-MnO2, β-MnO2, γ-MnO2 and δ-MnO2, and systematically studied their structural properties and photothermal conversion behavior. The α-MnO2 was proved to simultaneously possess large specific surface area (54.28 m2 g−1), developed < 10 nm pores, and high low-valence manganese (Mn2+ + Mn3+) content, as well as the robust photothermal conversion ability. The photothermally catalytic behavior was evaluated through degrading gaseous formaldehyde in both batch and fixed bed experiments. As we expected, the α-MnO2 showed the best activity for formaldehyde removal and the highest CO2 yield under xenon light illumination. In the meantime, the α-MnO2 had good stability of photothermal catalysis that was verified by the repeated cycling tests in the batch reactor and the durable test in the fixed bed reactor. Through detecting the intermediates and reactive oxygen species, a plausible mechanism of photothermal catalysis was proposed to illustrate the degradation route of formaldehyde on MnO2. The mechanism of photothermal catalysis degradation for formaldehyde over α-MnO2 [ABSTRACT FROM AUTHOR]

Novel ceramic foams loaded with Fe and Fe/Mn oxides were developed via geopolymerization process as catalysts for tar removal in syngas cleaning operations. The foams were realized through polymer scaffold template replica, by impregnating polyurethane or cellulose foams with a metakaolin based geopolymer slurry loaded with 19 wt% powdered Fe 2 O 3 and Mn 2 O 3 metal oxides. A thermal treatment up to 900 °C was applied to vitrify and partially crystallize into leucite the geopolymer binder. Foams from cellulose showed better structural properties compared to those from polyurethane. Preliminary test in real gasification conditions were carried out on a lab scale double fixed bed reactor. In working conditions, vitrified phases derived from geopolymer binder promoted the formation of mixed phases of (Fe, Mn) oxides and silicates, beneficial for improving the catalytic activity. Furthermore, foams loaded with mixed Fe-Mn oxides were more effective than granules in reducing the produced tar. [ABSTRACT FROM AUTHOR]

The objective of this research is to find the effectiveness factor of the catalyst particles for the most favorable conditions of the phthalic anhydride production in a fixed bed reactor, with the aim of achieving the highest rate of phthalic anhydride production compared to other secondary products and analyzing the areas of lower effectiveness for the modification of the reactor design. Initially, the material and the energy balances in the catalytic bed are solved to obtain the concentration and temperature profiles based on the radius and length of the reactor, using polymath software(Polymath® v6.2 Software Minitab 19 Matlab 2019) with the data from literature. Once the profiles reproducibility was verified using the initial data (inlet temperature, pressure in the reactor, reactor wall temperature, reactor radius and mass flow rate) the experimental design 35 carry out, which generates 243 "experiments", whose response variable (phthalic anhydride concentration) was obtained using Matlab. Subsequently, the variables were analyzed using the Minitab 18® that, through the response surface analysis method, allowed us to obtain the optimal values of the tested variables. Then, Subsequently, material and energy balances coupled with Fourier and Fick's laws, along with the effectiveness factor equation, were applied, resulting in the generation of 9 coupled differential equations. Upon implementing the finite difference method, this yielded 90 nonlinear algebraic equations, which were solved using the Polymath software. A total of 78 particles were preselected based on their radial and axial positions to determine the effectiveness factor profile, with values ranging from 0.83 to near unity. The lower values correspond to the points with higher temperature, as evidenced by the calculations performed. [ABSTRACT FROM AUTHOR]

The process of preparing methanol from carbon dioxide is one of the ways to solve the environmental problems caused by greenhouse gases, the problem of fossil energy depletion, and the problem of fuel exhaust emissions. However, after decades of development, the process of preparing methanol from carbon dioxide is still unable to achieve large‐scale industrialization. This critical review sharply points out the problems and obstacles that need to be solved urgently on the industrialization road of carbon dioxide methanol preparation process and summarizes its progress. The problems faced by the methanol production industry from carbon dioxide are first the thermodynamic constraints, second the lower reaction rate and conversion effect, and finally the energy loss. In order to solve these problems, this paper first introduces the active sites, structural effects, and dynamic changes of copper‐based catalysts, as well as the unique reaction mechanism and doping modification of indium‐based catalysts. Zinc and zirconium promoters and some metal oxide supports can form unique interactions with active components to improve the catalytic performance of the catalyst. Next, various kinetic models and applications of methanol production from carbon dioxide are summarized, which is an important bridge linking laboratory and industrialization; the advantages and disadvantages of fixed bed reactor and paddle reactor were compared. Finally, the full text is summarized and prospected. [ABSTRACT FROM AUTHOR]

MnO2 based photothermal catalysis has been demonstrated to be a promising technology to eliminate pollutants in air. However, the relationship between catalytic activity and MnO2 crystal phase has not been revealed. Herein, we hydrothermally synthesized four MnO2 catalysts, α-MnO2, β-MnO2, γ-MnO2 and δ-MnO2, and systematically studied their structural properties and photothermal conversion behavior. The α-MnO2 was proved to simultaneously possess large specific surface area (54.28 m2 g−1), developed < 10 nm pores, and high low-valence manganese (Mn2+ + Mn3+) content, as well as the robust photothermal conversion ability. The photothermally catalytic behavior was evaluated through degrading gaseous formaldehyde in both batch and fixed bed experiments. As we expected, the α-MnO2 showed the best activity for formaldehyde removal and the highest CO2 yield under xenon light illumination. In the meantime, the α-MnO2 had good stability of photothermal catalysis that was verified by the repeated cycling tests in the batch reactor and the durable test in the fixed bed reactor. Through detecting the intermediates and reactive oxygen species, a plausible mechanism of photothermal catalysis was proposed to illustrate the degradation route of formaldehyde on MnO2. The mechanism of photothermal catalysis degradation for formaldehyde over α-MnO2 [ABSTRACT FROM AUTHOR]

The generation and accumulation of coal gangue (CG) and coal slime (CS) are a serious cause of environmental pollution. The co-pyrolysis of CG/CS and pine sawdust (PS) is an effective method to reduce pollution and waste generation. In this work, the co-pyrolysis characteristics of CG/CS and PS were analyzed by the thermogravimetric analyzer and fixed bed pyrolysis reactor. The kinetics analysis showed that the activation energies decreased with the PS mixing ratio increased for CG/PS blends and CS/PS blends in the second pyrolysis stage. The synergistic effect on yield is quantified by comparing the results of the co-pyrolysis of CG/CS and PS blends with weighted results from the pyrolysis of CG, CS and PS individually. The results revealed that when the mixing ratio of CG:PS was 1:1, the difference between the experimental and calculated yields (2.9 %) and the H 2 yield (320 ml/g) were maximum. Among the CS/PS blends, these values are maximum when the mixing ratio of CS:PS is 3:1 (2.5 % and 450 ml/g). Furthermore, the alkali and alkaline earth metals K and Ca in the co-pyrolysis char catalyze the decomposition of the –OH functional group. • CG/CS and PS co-pyrolysis was studied by non-isothermal and isothermal conditions. • The alkali and alkaline earth metals in the co-pyrolysis char had a catalytic effect. • CG/PS1-1 and CS/PS3-1 mixing ratio had the highest hydrogen yield. [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]

The paper develops a design feasibility study of a multi-tubular polytropic fixed bed reactor for the one-stage ethanol to 1,3-butadiene (ETB) process employing a modified MgO-SiO 2 catalyst. The analysis quantifies the effect of the internal diffusion on scaling up the catalyst activity and selectivity by considering a complex chemistry of seven parallel/series reactions described by detailed kinetic modelling. The efficient numerical solution takes advantage from the MATLAB™ function bvp5c. The simulation model allows scanning the catalytic process by profiles of species' concentrations, reaction rates and effectiveness factors, inside the catalyst particle and over the reactor. The butadiene yield is controlled by the accumulation in particle of ethanol and key intermediates, as acetaldehyde and crotonaldehyde, related to internal chemical reaction with diffusion and external mass and heat transport rates. The catalyst performance depends significantly on the pellet size that becomes optimization variable for catalyst selection and reactor design. Catalyst particles in the range 2 to 3 mm with tubes of to 25 to 40 mm diameters are the most efficient for achieving 80% butadiene carbon selectivity suitable for an industrial process. The modelling approach is generic for calculating the catalyst effectiveness and designing catalytic chemical reactors involving complex reactions. [Display omitted] • Design of multi-tubular reactor for one-stage bioethanol to 1,3-butadiene process, MgO/SiO 2 catalyst, particle modelling. • Generic method for computing porous catalyst effectiveness involving complex reactions by using MATLABTM bvp5c routine • Catalyst particles of 2 to 3 mm achieve 84 % carbon selectivity with 25 to 40 mm tube diameter at 1.5 bar and 390 °C. [ABSTRACT FROM AUTHOR]

This research explores the depolymerization of waste polymethyl methacrylate (PMMAW) from dental material in fixed bed semi-batch reactors, focusing on three production scales: laboratory, technical and pilot. The study investigates the thermal degradation mechanism and kinetics of PMMAW through thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses, revealing a two-step degradation process. The heat flow during PMMAW decomposition is measured by DSC, providing essential parameters for designing pyrolysis processes. The results demonstrate the potential of DSC for energetic analysis and process design, with attention to standardization challenges. Material balance analysis across the production scales reveals a temperature gradient across the fixed bed negatively impacting liquid yield and methyl methacrylate (MMA) concentration. Reactor load and power load variables are introduced, demonstrating decreased temperature with increased process scale. The study identifies the influence of temperature on MMA concentration in the liquid fraction, emphasizing the importance of controlling temperature for efficient depolymerization. Furthermore, the research highlights the formation of aromatic hydrocarbons from the remaining char, indicating a shift in liquid composition during the depolymerization process. The study concludes that lower temperatures below 450 °C favor liquid fractions rich in MMA, suggesting the benefits of lower temperatures and slower heating rates in semi-batch depolymerization. The findings contribute to a novel approach for analyzing pyrolysis processes, emphasizing reactor design and economic considerations for recycling viability. Future research aims to refine and standardize the analysis and design protocols for pyrolysis and similar processes. [ABSTRACT FROM AUTHOR]

The thermo-chemical conversion of biomass wastes is a practical approach for the value-added reclamation of bioenergy in large quantities, and pyrolysis plays a core role in this process. In this work, poplar (PR) and cedar (CR) were used as staple wood biomasses to investigate the apparent kinetics of TG/DTG at different heating rates. Secondly, miscellaneous wood chips (MWC), in which PR and CR were mixed in equal proportion, were subjected to comprehensive investigations on their pyrolysis behavior and product evolution in a fixed bed reactor with pyrolysis temperature, catalyst, and the flow rate H2O steam as influencing factors. The results demonstrated that both PR and CR underwent three consecutive pyrolysis stages, the TG/DTG curves shifted to higher temperatures, and the peak temperature intervals also enhanced as the heating rate increased. The kinetic compensation effect expression and apparent reaction kinetic model of CR and PR pyrolysis were obtained based on the law of mass action and the Arrhenius equation; the reaction kinetic parameter averages of Ea and A of its were almost the same, which were about 72.38 kJ/mol and 72.36 kJ/mol and 1147.11 min−1 and 1144.39 min−1, respectively. The high temperature was beneficial for the promotion of the pyrolysis of biomass, increased pyrolysis gas yield, and reduced tar yield. This process was strengthened in the presence of the catalyst, thus significantly increasing the yield of hydrogen-rich gas to 117.9 mL/g-biomass. It was observed that H2O steam was the most effective activator for providing a hydrogen source for the whole reaction process, promoted the reaction to proceed in the opposite direction of H2O steam participation, and was beneficial to the production of H2 and other hydrocarbons. In particular, when the flow rate of H2O steam was 1 mL/min, the gas yield and hydrogen conversion were 76.94% and 15.90%, and the H2/CO was 2.07. The yields of H2, CO, and CO2 in the gas formation were significantly increased to 107.35 mL/g-biomass, 53.70 mL/g-biomass, and 99.31 mL/g-biomass, respectively. Therefore, H2 was the most dominant species among gas products, followed by C-O bond-containing species, which provides a method for the production of hydrogen-rich gas and also provides ideas for compensating or partially replacing the fossil raw material for hydrogen production. [ABSTRACT FROM AUTHOR]

The Fischer-Tropsch synthesis converted hydrogen and carbon monoxide into linear hydrocarbons as liquid fuel. Iron and cobalt were used as polymerization catalyst, that impregnated on HZSM-5. The Fe-Co/HZSM-5 could be applied as bifunction catalyst which combined polymerizing synthesis gas and long chain hydrocarbon cracking for making biofuel. The objective of this study is observing the effect of temperature and composition of iron and cobalt combination, supported by HSZM-5 (Fe-Co/HZSM-5) catalyst on fuel product composition. The results obtained from this study would be used to find optimum condition for various iron and cobalt ratio in the catalyst. The mesoHZSM-5 was prepared from ammonium ZSM-5 over calcination, desilication, and dispersion. The mixed solution consisted of Co(NO3)2.6H2O and Fe(NO3)3.9H2O were used as precursor for incipient wetness impregnation on HZSM-5. The catalyst performance was observed in a continuous fixed bed reactor using Fe-Co/meso-HZSM-5 catalyst with synthesis gas at various composition iron and cobalt ratio (10-40 % wt. Fe in Co), various temperature (225-275 °C) at 20 bars. All catalysts were reduced in situ in the reactor. The 10Fe-90Co/mesoHZSM-5 catalyst was more suitable for FTS at 250 °C with alkane (20.49 %) as the main product and alcohol as the by-product (79.51 %). The others catalysts composition of 20-40 % Fe (by weight) in Fe-Co were more suitable for FTS at 225-250°C because under these conditions, alkanes as the main product were obtained in relatively higher compositions compared to other compounds. The mechanism of paraffins, olefins, aldehydes and alcohols formation in this FTS reaction followed the hydrogen assisted CO dissociation with CO-insertion mechanism. [ABSTRACT FROM AUTHOR]

It is well known that calcium oxide (CaO) has better catalytic efficiency than most heterogeneous catalysts in many transesterification reactions. However, the gradual deactivation problem prevents its large-scale application in industry. In this paper, the deactivation mechanism of CaO in a fixed-bed reactor is investigated based on the transesterification reaction of propylene carbonate and methanol. The leaching amount of CaO during the reaction was estimated by the concentration of Ca in the products. The pretreated and recovered catalysts were characterized by FT-IR, XRD, TG-MS and SEM-EDS. It is evident from experiments and characterization that the deactivation process of CaO is accompanied by the leaching of calcium species and the generation of CaCO3, which are also verified by DFT calculations. At high temperature and high weight hourly space velocity, the deactivation was attributed to the formation of dense CaCO3 shell, which prevents the contact between the feedstock and the active species inside. [ABSTRACT FROM AUTHOR]

Bio-aviation fuels were prepared by the catalytic upgrading of lignocellulose fast pyrolysis oil, or bio-crude. Hydrotreating was performed for upgrading the oils. The oxygen atoms in the bio-crude were removed using the fixed bed continuous flow reaction systems composed of the multiple catalyst beds. The complete deoxygenation was observed and the possible applications of bio-crude-derived deoxygenated hydrocarbon fuels for aviation fuels were discussed. The detailed characterizations of catalysts using Raman, XRD, XPS, TEM, and other methods confirmed the improved activity or selectivity of the catalysts used in this study. The reaction products were also analyzed using GC, GPC, Karl Fischer titration, and other methods for understanding the reaction pathways and for obtaining the insight to improve the upgrading process. [ABSTRACT FROM AUTHOR]

In hot gas cleaning of biomass gasification gas conversion results of a fixed bed MgO-NiO catalyst tested in a simulated biomass gasification gas at a naphthalene inlet content of 5 g / Nm³ in the presence of 100 ppmv H2S have shown so far, that catalytic filtration is feasible, if a temperature of 800°C and a space velocity of 3054 or 3207 h-1, respectively, is applied by integrating the catalyst in the cylindrical hollow space of a hot gas filter candle. In this work a novel patented tar reforming catalyst C&CS #1050 B is presented that exhibits a distinctly superior catalytic performance in direct comparison at a total model tar content of 13 g / Nm³. Complete conversion at a space velocity of 6000 h-1from 750°C down to 650°C was measured because of its more than 4-fold higher NiO density in a fixed bed compared to the MgO-NiO catalyst and its approx. 3.5 – 4.5 times higher BET surface area compared to typical commercial steam reforming catalysts. Due to its 21-fold higher NiO density compared to a catalyst integrated in a filter candle as catalytic layer, fixed bed based catalytic filter candles are superior to candles of catalytic layer design. Based on the evidence of 99% model tar conversion at 750°C also at a content of 4.9 g / Nm³ naphthalene and 9.3 g / Nm³ toluene of a C&CS #1050 B filled candle of 60 mm outer diameter complete real tar abatement with a capacity of 13 g / Nm³ is estimated at this temperature allowing a more energy-efficient hot gas filtration and enlarging the applicability of catalytic hot gas filters to higher tar inlet contents. [ABSTRACT FROM AUTHOR]

Entrapped lipase derived from Candida rugosa can be used as an alternative for commercial heterogeneous catalysts in the biodiesel synthesis process. The inclination towards a recirculating reactor with lipase-containing beds stems from its capability to simultaneously improve both yield and reproducibility in the biodiesel synthesis process. To industrialize biodiesel production with entrapped lipase in a recirculating reactor, optimization is essential, and this can be estimated using a kinetics model. In this context, a kinetics model based on the Ping-Pong Bi-Bi mechanism was developed for enzyme transesterification. Following this, experiments on biodiesel synthesis were carried out in a fixed-bed reactor with a recirculated substrate, and a biodiesel concentration of 2177.231 mol/m3 was achieved from 917.804 mol/m3 triglyceride. In this study, 3 models, namely Model 1, 2, and 3, were developed based on the Ping-Pong Bi-Bi mechanism, and each has assumptions that determine its complexity. To validate these models, two sets of secondary data were taken and fitted into the respective model. The sum relative error is used to express the differences between model and experimental data. Model 1, predicting each component in transesterification, exhibited the highest error of 1.64, while Model 3, assuming excess alcohol and incorporating a pseudo-steady-state for di- and monoglyceride, yielded the lowest error. Despite these variations, every model demonstrated good agreement in following each component profile accurately, providing a more precise description of the reaction elements. [ABSTRACT FROM AUTHOR]

Although coal chemical looping gasification (CCLG) is a promising technology for the efficient utilization of coal, limited studies concerned about the industrial application of oxygen carrier in CCLG system owing to its performance requirements including high reactivity with solid fuel, high carbon conversion, and good mechanical property. To meet the requirements of oxygen carriers in CCLG system, novel Fe-Ni composite oxygen carrier (OC) samples were successfully prepared. The performances of these OCs were evaluated in a fixed bed reactor, where they were reduced by solid fuel and then fully oxidized by air. Both fixed bed tests and thermodynamic analysis showed that the prepare OCs exhibited high reactivity with coal and syngas selectivity, making them suitable for the CCLG process. Specifically, when the loading amount of NiO was 20 wt%, the Fe-Ni composite OCs achieved the highest carbon conversion (93.03%) and synthesis gas selectivity (73.29%). Additionally, the thermogravimetric data revealed that the Curie temperature of the OCs was higher than 550°C, making them suitable for magnetic separation of the OC particles and carbon residue in the CCLG system. [ABSTRACT FROM AUTHOR]

Hydrocracking of Crude Palm Oil (CPO) in fixed-bed reactor was studied using a six-lump computational fluid dynamics (CFD) model. The experiment was conducted in the reactor at the temperatures of 673-773 K with CPO flow rates between 60 and 300 g/h. The predictive modeling of CPO cracking demonstrated a strong correlation with the experimental data. CFD simulation investigated the influence of input flow rates and temperatures on species mass fraction and product yield in the reactor. At the lowest input flow rate, the highest results of diesel (31.7 %), kerosene (17.1 %), gasoline (7.62 %), and gas (3 %) were produced. As CPO flow rate increased from 60 to 300 g/h, the concentration of CPO in the reactor increased while the concentration of the desired products decreased at the reactor outlet. The highest total oil fraction was obtained at 773 K and a 60 g/h flow rate with oil fraction value of 59.42 %. • Experimental and CFD modeling of CPO hydrocracking in a fixed bed reactor. • A CFD model with a 6-lump kinetic scheme of CPO hydrocracking was developed. • Axial hydrodynamics and reaction kinetics were examined via the CFD model. • Predicted gas velocity and temperature are similar trends to experimental data. • CFD simulations predicted biofuel yield in the reactor with an error 11 %. [ABSTRACT FROM AUTHOR]

Thermochemical conversion is a promising waste plastic recycling technology from both an economic and environmental point of view, as it can convert plastics into high-value chemicals. In this work, the co-production of hydrogen and carbon nanotubes (CNTs) by catalytic pyrolysis of polyethylene over Fe/ZSM-5 catalysts with different Fe loading (5, 10, 20 and 30 wt%) was investigated using a two-stage fixed bed reactor. The results show that the yield of CNTs and hydrogen increases first and then decreases with the increase of Fe loading. The 20Fe/ZSM-5 catalyst generated the highest CNTs yield of 262.24 mg/g PE and the maximum hydrogen production of 31.72 mmol/g PE. The fresh and spent catalysts were characterized by XRD, H2-TPR, SEM, TEM, etc., in order to explore the correlation between the catalytic activity and the Fe active metal load of the catalysts. The results showed that, within a certain range, the number of active sites increased with the increase of Fe loading, which promoted the conversion of hydrogen and CNTs. However, when the Fe loading reached 30%, the active particles agglomerated and inhibited the growth of CNTs. 30Fe/ZSM-5 catalyst produced many carbon nanoonions (CNOs) and carbon nanofibers (CNFs). Overall, in terms of the yield of the produced hydrogen and CNTs, the 20Fe/ZSM-5 catalyst shows the best catalytic performance. • A series of Fe-based catalyst was prepared for polyethylene pyrolysis. • Appropriate increase of Fe content can enhance CNTs and H 2 yield. • The highest CNTs yield of 262.24 mg/g PE was obtained from 20Fe/ZSM-5 catalyst. • The highest H 2 yield of 31.72 mmol/g PE was obtained from 20Fe/ZSM-5 catalyst. • More carbon nanofibers were obtained from 30Fe/ZSM-5 catalyst. [ABSTRACT FROM AUTHOR]

This study investigates the utilisation of coal tar naphthalene oil fraction (CTNOF), an economical by-product derived from the iron-steel industry, for the production of valuable chemicals, with a particular focus on methylnaphthalenes (MNs) and dimethylnaphthalenes (DMNs). Of specific interest is 2,6-dimethylnaphthalene (2,6-DMN), a pivotal component in the manufacture of polyethylene naphthalate (PEN). The intricate and costly nature of 2,6-DMN production currently poses challenges to the commercial viability of PEN. This study provides the potential heterogeneous reaction pathways for the synthesis of MNs and DMNs via methylation, disproportionation, and isomerisation of CTNOF. The utilisation of CTNOF was investigated in a laboratory-scale fixed bed reactor operating at atmospheric pressure using a mixture of CTNOF: methanol having 1:5 mass ratio over HBeta zeolite catalyst at a temperature of 400 °C and weight hourly space velocity of 2 h−1. The results reveal the successful methylation of CTNOF over the HBeta zeolite catalyst, initially achieving high naphthalene conversion, particularly into 2-MN. This highlights the potential of CTNOF as an alternative feedstock for the production of value-added chemicals. While naphthalene conversion initially reaches 99 wt% within 0.5 h of operation, it gradually decreases to approximately 10 wt% over extended run times. Notably, coke deposition significantly deactivates the HBeta zeolite catalyst during CTNOF methylation, impacting naphthalene conversion. A substantial proportion of naphthalene compounds convert to methylnaphthalenes early in the reaction, predominantly 2-MN, increasing from 14 wt% (in CTNOF feedstock) to 87 wt%. Among DMNs, selectivity for 2,6-DMN, 2,7-DMN, 1,3-DMN, and 1,7-DMN increases, while other DMN isomers exhibit a sharp decrease in selectivity. The distribution of 2,6-triad DMNs rises from 38 wt% in feedstocks to 52–55 wt% with extended reaction times, attributed to MN conversion to DMNs and potential isomerisation from other DMNs. This study underscores the feasibility of using CTNOF for the direct synthesis of valuable chemicals, specifically 2,6-DMN and 2-MN, through methylation over HBeta zeolite catalysts. However, it emphasises the critical role of residence time in coke deposition and the need for optimisation, particularly regarding this parameter, to ensure the efficiency of this catalytic process. [ABSTRACT FROM AUTHOR]

An extensive review of slurry bubble column reactor and fixed bed reactor steady state models for Fischer–Tropsch synthesis is presented in this work. Material, energy and momentum balance equations are presented here along with the relevant findings of each study for modelling purposes. For fixed bed reactor models, one-dimensional and two-dimensional models can be differentiated, with the latter being better at predicting hot spots and thermal runaways, although the computational effort required solving them is also higher. Fixed bed reactors can also be classified as pseudo-homogeneous or heterogeneous models, the former considering that all phases are in thermal and chemical equilibrium, and the latter having different profiles for the catalyst particles, generally including a pellet model. For slurry bubble column reactors, single-class and double-class bubble models can be differentiated. The double-class bubble models represent better churn-turbulent regimes at the expense of a higher computational effort. [ABSTRACT FROM AUTHOR]

Tetrahydrofuran (THF) manufacture is explored in this work using the route from 1, 4 butanediol (BD) in the fixed bed chromatographic reactor (FBCR). Major problem faced in this manufacture is the existence of THF-water minimum boiling azeotrope. Use of FBCR helps to circumvent the azeotrope, thereby offering a simplified process. Binary adsorption experiments, reaction in the FBCR environment and regeneration experiments are presented. Use of molecular sieves and rectification helps to obtain almost pure THF as the product and BD for recycle. A complete process to manufacture THF from BD is thus developed. [ABSTRACT FROM AUTHOR]

Carbide slag is a typical high calcium industrial solid waste with excellent CO2 absorption performance, but the reaction activity and CO2 absorption performance of pure carbide slag in calcium cycling will decrease with the increase of cycling times. Efficient and stable calcium-magnesium zinc composite absorbents was synthesized using carbide slag as the calcium source, MgO and ZnO as dopants. Effects of synthesis process conditions and doping amount on the absorption performance of CO2 composite absorbent were investigated in a fixed bed reactor, as well as the changes in the internal structure of the absorbent during cyclic absorption. The results show that the absorbent synthesized by dry physical mixing method has a richer pore structure than wet mixing method. Mg and Zn elements are evenly dispersed on the surface of the carbide slag, effectively improving the anti-sintering performance and reaction activity of the carbide slag. The modified composite absorbent has higher CO2 absorption performance during the cycling process, and after 20 cycles, CO2 absorption capacity of the composite absorbent synthesized by dry physical mixing method can still reach 0.42 g/g. [ABSTRACT FROM AUTHOR]

Ni–Al layered double hydroxide‐derived catalyst is modified with Ca and Co to improve their properties for ethanol steam reforming (ESR). The catalysts are prepared by coprecipitation and are characterized through N2 adsorption–desorption measurements, X‐Ray diffraction, temperature programmed reduction, temperature programmed oxidation, and NH3‐temperature programmed desorption. Catalyst activity tests are performed between 400 and 600 °C with the calcined catalysts and without reduction using ethanol and water in a 1:3 ratio in a fixed bed reactor with online gas chromatography analysis. The partial substitution of Ni by Co and Ca decreases the acidity of the catalyst. All samples remain stable after the reaction at 600 °C for 8 h and present a full ethanol conversion and high hydrogen selectivity, above 90%. The samples modified by Ca or Co are reduced to metallic phase during the reaction and reveal a smaller crystallite size than NiAl. The sample with Ca prepared with a different precipitant results in a catalyst with a more thermally stable active phase, low acidity, and higher specific surface area. This catalyst presents smaller crystallite size and low‐carbon formation after the reaction at 600 °C for 8 h, demonstrating higher potential for hydrogen production by ESR. [ABSTRACT FROM AUTHOR]

This research shows the effect of a catalyst supported on mordenite (natural and modified) impregnated with nickel, calcium, and potassium on palm kernel shell gasification for hydrogen production. The gasification process was carried out using a lab-scale fixed bed reactor at 900 °C with steam as gasifying agent. The use of the catalysts significantly improved the hydrogen production and the incorporation of metals in the mordenite increased hydrogen selectivity. The maximum H 2 content in the non-catalyzed gasification was approximately 34 mol%, while in the treatments with catalysts it ranged between 40 and 73 mol%. The T2-C5 catalyst impregnated with Ni, Ca, and K presented the highest H 2 content (72.9 mol%), which is associated with the synergistic interaction of nickel, calcium, and potassium. This catalyst presented the highest strong acidity (1.30 mmol NH 3 g−1) and the highest crystallinity (85.8%) compared to the other catalysts, properties that influenced the catalytic performance. • Synthesis of novel catalysts for H 2 production from biomass gasification. • Catalysts were supported on mordenite with different Ca/Ni, K/Ni and Ca/K/Ni ratios. • Catalysts were characterized with different techniques and used in gasification. • A synergistic effect of Ca, K and Ni favored hydrogen production. • Acidity and crystallinity influenced catalyst performance in the reaction. [ABSTRACT FROM AUTHOR]

The catalytic properties of supported Pt-containing catalysts for dimethoxymethane partial oxidation (DMM PO) into syngas was studied in a tubular fixed bed reactor at atmospheric pressure and relatively low temperatures (∼300–500 °C). Comparative studies of granular 0.5–1.9 wt % Pt/Ce 0.75 Zr 0.25 O 2–δ and structured 0.08 wt% Pt/8 wt% Ce 0.75 Zr 0.25 O 2–δ /6 wt% η-Al 2 O 3 /FeCrAl catalysts in DMM PO were performed. The SEM and STEM HAADF techniques were used for catalyst characterization. The structured catalyst was proved promising for producing syngas by the DMM PO reaction for SOFC feeding applications. In particular, at atmospheric pressure, temperature 400 °C, and the reaction mixture (28.6 vol% DMM, 14.3 vol% O 2 , 57.1 vol% N 2) feed rate of 5 L/(g·h), this catalyst provided complete conversion of DMM and O 2 to syngas with a total H 2 and CO content of 69 vol% and syngas productivity of ∼8 L/(g · h). • Structured Pt/CZ/Al 2 О 3 /FeCrAl catalyst was studied in DMM PO for the first time. • Pt/CZ in the structured catalyst works more efficiently than in the granular catalyst. • The catalyst provides 100% DMM conversion to syngas with H 2 +CO content of 69 vol%. • The catalyst with 80 mg Pt is sufficient for 1 kW SOFC integrated DMM PO reformer. [ABSTRACT FROM AUTHOR]

Pyrolytic reforming of toluene over Ni-based catalysts loaded on nano-sized and micro-sized γ-Al 2 O 3 is investigated in a fixed bed reactor under the temperature from 500 °C to 800 °C. The physicochemical properties of γ-Al 2 O 3 and Ni/Al 2 O 3 catalysts were characterized by HRTEM, XPS, XRD and H 2 -pulse chemisorption. The metal Ni loaded on micro-sized γ-Al 2 O 3 gave the steady toluene conversion of more than 80% and graphite yield of 87.3% after 1 h of reforming reaction. The rapid decrease of H 2 yield from 5.2 mmol/g-toluene to 0.4 mmol/g-toluene over Ni/nano-Al 2 O 3 was obtained during the 1 h of reforming reaction at 500 °C. The particle size of metal Ni over nano-sized and micro-sized γ-Al 2 O 3 were centered at 7.8 nm and 28.8 nm, respectively. The metastable NiC x crystallites were observed over the spent Ni/nano-Al 2 O 3 catalyst, while only metal Ni were obtained over the spent Ni/micro-Al 2 O 3 catalyst. Ni0+ particle size-dependent crystalline phase was evidenced by MD simulations, where incorporation of more carbon atoms was achieved on small Ni particles. The energy barrier for –CH 2 dehydrogenation over Ni 32 C, Ni 4 C and Ni 3 C were estimated to be 90.2, 105.1 and 116.0 kJ/mol through the DFT simulation, respectively. It can be concluded that the crystalline Ni phase was maintained over Ni/micro-Al 2 O 3 with large Ni particle size, prolonging the catalytic endurance and promoting the CNTs (Carbon Nanotubes) growth without the deposition of unexpected amorphous carbon. • The influence of γ-Al 2 O 3 on Ni/Al 2 O 3 catalytic reforming performance was investigated. • Ni0+ particle size-dependent pyrolytic reforming for co-production of H 2 and CNTs was revealed. • The carbon solubility on Ni particles with different sizes was simulated. [ABSTRACT FROM AUTHOR]

In the large-scale production of Diethyl Oxalate (DEO), numerous control and optimization challenges are faced. These issues are targeted in this study by implementing a gain scheduling approach to control a catalytic fixed bed multi-tubular reactor designed for DEO production. A novel inferential modeling method, developed using Python and response surface methodology, was applied to simulate the dynamics of the reactor, and the inlet coolant temperature was identified as the most influential parameter. An inferential control system was implemented that utilized gain scheduling for Proportional Integral Derivative (PID) controllers. The results showed that the proposed PID controller gains offered fast and stable responses, even at high conversion setpoints. However, minimization of response overshoot at high amplitudes of step changes proved challenging, leading to a decrease in conversion estimator accuracy. The use of a quadratic model from response surface methodology for the regression of the inferential estimator was proposed, showing improved prediction accuracy over the linear model. These findings provide valuable insights and guide future optimization in the design and operation of reactors for large-scale DEO production. [Display omitted] • Reactor Modeling : Deep insights into the coupling reactor dynamics via Simulink. • Most Effective Parameter : Coolant temperature identified through statistical analysis. • Novel Estimation Method : Python-based approach for inferential control's estimator. • Enhanced Prediction Accuracy : Quadratic model improves estimator precision. • Gain Scheduling Control: Implemented gains ensured stability and speed of responses. [ABSTRACT FROM AUTHOR]

Short-chain olefins are the important feedstock for the chemical industries. The selection of a proper catalyst for oxidative dehydrogenation (ODH) reaction is critical. Here, the study summarized different catalysts by physicochemical techniques such as BET surface area, Raman spectroscopy, and temperature programmed reduction (TPR). The BET analysis of different catalysts gives an optimum value of active and metal loading catalysts for optimum alkenes selectivity. From different Raman spectroscopy analyses, the study pointed out the factor responsible for varying mono vanadate and poly vanadate formation. From TPR analysis of different catalysts, this study pointed out the factors that varied on increasing or decreasing temperature and the effect on the selectivity of alkenes. The effect of different operating conditions was studied. Without catalyst regeneration after each ODH run, the catalyst under the study shows stable behavior and increases the selectivity of the desired product. The CREC riser simulator was used for ODH of propane and ethane, while two zones of fluidized bed reactor (TZFBR) and ICFBR reactors were used for ODH of butane. From the study of MoO3/MgO catalyst, it was observed that TZFBR have high selectivity of butadiene than CFBR and fixed bed reactor. It was concluded that the catalyst VOx–Nb/La-ɣAl2O3 has high conversion (20.1%) of ethane and good selectivity of (85.7%) of ethylene, while in ODH of propane and butane the catalyst 7.5 VOx/ɣAl2O3·ZrO2 (1:1) and MoO3/MgO have high selectivity of propane and 1,3-butadiene respectively. This review will help researchers in decision making for the selection of proper catalyst for ODH of alkane to alkenes. [ABSTRACT FROM AUTHOR]

Although the catalytic pyrolysis of low-density polyethylene (LDPE) to produce light olefin has shown potential industrial application advantages, it has generally suffered when using higher pyrolysis temperatures. In this work, Mg-modified Fe-ZSM-5 was used for catalytic conversion of LDPE to obtain light olefin in a fixed bed reactor. The effects of catalyst types, pyrolysis temperatures, and Mg loading on the yield of light olefin were investigated. The 1 wt% Mg loading slightly improved the yield of light olefin to 38.87 wt% at 395 °C, lowering the temperature of the pyrolysis reaction. We considered that the higher light olefin yield of Fe-Mg-ZSM-5 was attributed to the introduction of Mg, where Mg regulated the surface acidity of the catalyst, inhibited the secondary cracking reaction, and reduced coking during the pyrolysis process. Furthermore, the addition of Mg also dramatically reduced the average particle size of Fe oxides from 40 nm to 10 nm, which is conducive to a lower catalytic reaction temperature. Finally, the spent catalyst could be easily regenerated at the conditions of 600 °C in airflow with a heating rate of 10 °C/min for 1 h, and the light olefin yield remained higher than 36.71 wt% after five cycles, indicating its excellent regeneration performance. [ABSTRACT FROM AUTHOR]

The utilization of corncob residues in pyrolysis offers a promising source for both renewable energy and chemical production. In this study, corncob was decomposed in the presence of aluminum oxide nanoparticles (Al2O3 NPs) catalyst using a fixed bed reactor under an inert atmosphere. Pyrolysis of corncob was carried out in the presence of Al2O3 NPs at different heating rates i.e. 5, 10, 15 and 20°C/min in an oxygen-free atmosphere using TGA technique. Kinetic and thermodynamic studies were performed using the best fit models including Ozawa–Flynn–Wall (OFW), Kissinger–Akahira– Sunose (KAS) and Friedman methods. The average activation energies for Friedman, OFW, KAS were 177.3, 162.9 and 167.8 kJ/mol, respectively for pure corncob and 111.0, 102.5 and 118.06 kJ/mol, respectively for Al2O3- corncob sample. Activation energy was found to be the lowest in the OFW model. Results showed that the presence of Al2O3 NPs catalyst not only reduced pyrolysis temperature and activation energy but also improved the quality of bio-oil. [ABSTRACT FROM AUTHOR]

The impact of ZrO2 as a catalytic promoter for nickel-based alumina supported catalysts has been studied for the hydrogen synthesis via glycerol steam reforming. Hydrogen is a promising contender of clean fuel and has a key significance in the quest of an environment-preservation, low emission and more sustainable energy approach. Glycerol is a by-product produced during production of biodiesel by trans-esterification of vegetable oils. The higher hydrogen content in glycerol makes it the potential renewable feedstock for hydrogen production. Steam reforming process is the best method available which is highest in energy efficiency and most importantly most economical. The production of catalysts was based on the wet impregnation and co-precipitation methods. The majority of the bulk and surface properties of different synthesized catalysts were considered and determined by several characterization techniques like X-ray diffraction technique, BET surface area and scanning electron microscopy. The performance of catalyst is based on glycerol conversion and hydrogen yield obtained from the steam reforming process taking place in the fixed bed catalytic reactor. The effect of different operating conditions like contact time, temperature, metal loading, and steam to glycerol ratio were investigated to produce maximum hydrogen and glycerol conversion. The results show that the incorporation of promoter 2 % ZrO2 improved the activity of Ni/Al2O3 catalysts significantly resulting 96 % glycerol conversion, 84 % hydrogen production and greater stability at contact time = 15 kg cat s/mol, temperature = 800 °C, steam to glycerol ratio = 9:1 mol/mol, and pressure = 1 atm. [ABSTRACT FROM AUTHOR]

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Methylchlorosilane was synthesized by silicon powder and methyl chloride in a straight-tube fixed stirred bed reactor. The performance of three composite copper catalysts was evaluated by calculating the selectivity and silicon conversion rate of dimethyl dichlorosilane (M2). The results show that the catalytic performance of self-produced powder C is relatively good. The average selectivity of M2 with powder C is 91. 89% in the reaction, and the silicon conversion rate is 59. 24%. Powder C is thinner and finer, it also has higher specific surface area, and lower density and finer particle size, which is beneficial to form more active centers with silicon powder in the synthesis of methylchlorosilane. [ABSTRACT FROM AUTHOR]

• Cl distribution and speciation were determined during MSW pellets pyrolysis. • Chlorine mainly distributed in char (42.36–65.29 %) and gas (26.66–35.03 %). • Inorganic-Cl was the main form of chlorine in char. • Organic-Cl was converted into inorganic-Cl during MSW thermal decomposition. • Chlorine release was inhibited by the unprosperous pores in char. The migration process of chlorine during municipal solid waste (MSW) pellets pyrolysis was studied in a fixed bed reactor. Distribution and speciation changes of chlorine at different pyrolysis temperatures were determined by ion chromatography (IC) and X-ray photoelectron spectroscopy (XPS) analyses. Results showed that chlorine was mainly distributed in pyrolysis char (42.36–65.29 %) and gas (26.66–35.03 %) after MSW pellets pyrolysis. With the temperature increasing, chlorine in char and tar was enriched due to the increase of chlorine release and the decrease of product yields, with chlorine concentration increasing to 3498 ppm and 1415 ppm at 800 °C, respectively. Results of chlorine forms analysis indicated that most of the organic-Cl in MSW was released into the volatiles during pyrolysis due to the dissociation of C Cl. Inorganic-Cl became the dominant form of chlorine in char after pyrolysis, with the proportion increasing from 46.69 % (raw) to 61.22 % (500 °C), which also suggested that part of organic-Cl was converted into the inorganic-Cl. Notably, the proportions of inorganic-Cl decreased at >600 °C due to the migration of inorganic. In addition, the pyrolysis release behavior of chlorine was affected by the pore structure of char, which could be inhibited by the unprosperous pores in char, especially at low temperatures (<600 °C). These findings provided a reference for the chlorine regulation of MSW pyrolytic products. [ABSTRACT FROM AUTHOR]

Currently, most plastic waste stems from packaging materials, with a large proportion of this waste either discarded by incineration or used to derive fuel. Accordingly, there is growing interest in the use of pyrolysis to chemically recycle non-recyclable (i.e., via mechanical means) plastic waste into petrochemical feedstock. This comparative study compared pyrolysis characteristics of two types of reactors, namely fixed and fluidized bed reactors. Kinetic analysis for pyrolysis of SRF was also performed. Based on the kinetic analysis of the pyrolytic reactions using differential and integral methods applied to the TGA results, it was seen that the activation energy was lower in the initial stage of pyrolysis. This trend can be mainly attributed to the initial decomposition of PP components, which was subsequently followed by the decomposition of PE. From the kinetic analysis, the activation energy corresponding to the rate of pyrolysis reaction conversion was obtained. In conclusion, pyrolysis carried out using the fluidized bed reactor resulted in a more active decomposition of SRF. The relatively superior performance of this reactor can be attributed to the increased mass and heat transfer effects caused by fluidizing gases, which result in greater gas yields. Regarding the characteristics of liquid products generated during pyrolysis, it was seen that the hydrogen content in the liquid products obtained from the fluidized bed reactor decreased, leading to the formation of oils with higher molecular weights and higher C/H ratios, because the pyrolysis of SRF in the fluidized bed reactor progressed more rapidly than that in the fixed bed reactor. [ABSTRACT FROM AUTHOR]

Hierarchical Beta zeolites with interconnected intracrystalline mesopores and high structural stability are highly attractive for catalytic applications involving bulky reactants. Here, by introducing a suitable amount of polydiallyldimethylammonium chloride into the initial synthesis system, micron-sized Beta zeolite crystals with abundant hierarchical porosity (Beta-H) were hydrothermally synthesized. The sample named Beta-H_1 exhibited very high catalytic activity and durability for the Friedel–Crafts acylation of anisole with acetic anhydride. A 92% conversion rate of acetic anhydride could be achieved after 1 h of reaction in a fixed bed reactor, and 71% conversion still remained after 10 h, much better than the rate for conventional Beta zeolite (which decreased rapidly from 85% to 37% within 10 h). The enhanced catalytic performance of Beta-H zeolites could be mainly attributed to the relatively lower strong acid density and the faster transport rate of the hierarchical zeolites. In addition, Beta-H showed high structural stability and could be easily regenerated via high-temperature calcination without obvious loss in catalytic activity, demonstrating its great potential for catalytic applications in the industrially important Friedel–Crafts acylation process. [ABSTRACT FROM AUTHOR]

The synthesis of ZSM-5 zeolite with different silicon to aluminum ratios (SAR) was performed under microwave radiation. The synthesized samples were ion-exchanged with ammonium nitrate to form the proton form of the zeolite (H-ZSM-5) and then evaluated in a fixed bed reactor for methanol conversion to light olefins. The modified ZSM-5 zeolite samples showed excellent selectivities toward light olefins (C2= , C3= , and C4=) and the selectivities were in the range of 75.2 and 82.7%. The catalyst's lifetime was proportional to the ratio of SAR, and the lifetime was enhanced from 7 to 33 h by increasing the SAR from 30 to 150. An additional increase in the SAR from 150 to 750 led to a reduction in the lifetime from 33 to 14 h. On the other hand, the selectivity to propylene was proportional to the ratio of SAR, while the selectivity toward ethylene showed an inverse proportionality as the SAR increases. The zeolitic properties of the synthesized ZSM-5 zeolites demonstrated the influence of textural and acidity properties on the catalytic performance in the MTO reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • PCB was co-pyrolyzed in fixed and fluidized bed (FB) pyrolyzers with Ca-based additives. • Catalytic and dehalogenation capacities of CaO, Ca(OH)2, and CaO + Ca(OH)2 were compared. • CaO reduced the halogen content of bio-oil up to 80 and 92% in fixed bed and FB. • Halide fixation in the solid phase by additives was more effective in FB than fixed bed. • Up to 40.6% liquid recovery was achieved in a FB containing CaO + Ca(OH) 2. This study compares the impact of the calcium-based additives and the pyrolyzer on the recovery and the halide content of the oil produced from the pyrolysis of paper-laminated phenolic resin printed circuit boards (FR2-PCB). The preliminary experiments showed that the maximum liquid recovery (40.6%) was achieved in a fluidized bed pyrolyzer containing a 50:50 mixture of CaO and Ca(OH) 2 operating at T = 620 °C and PCB-to-additive ratio (FR2/A) = 5.4 g/g for 22 min. Extra tests were then carried out under these conditions in fixed and fluidized bed pyrolyzers to separately explore the impact of CaO, Ca(OH) 2 , and CaO + Ca(OH) 2 on the liquid recovery (L R) and the halogen content of the non-solid products. In the fluidized bed, L R in the presence of CaO, Ca(OH) 2 , and CaO + Ca(OH) 2 was 34.5%, 41.2%, and 38.9 wt%, respectively. The fraction of phenolic compounds in the pyrolysis oil ranged from 86% to 93%, about 1–3% higher than the corresponding values in the fixed bed. Using additives led to lower halide content in the pyrolysis oil of the fluidized bed than that of the fixed bed. However, the opposite trend was observed in the absence of additives. Regardless of the type of pyrolyzer, Ca(OH) 2 was more successful than CaO in increasing L R , whereas CaO was more effective than Ca(OH) 2 in pyrolysis oil dechlorination. Co-pyrolysis of FR2-PCB and CaO + Ca(OH) 2 in a fluidized bed reactor was identified as a practical approach to enhance the recovery of pyrolysis oil comprising only 5% of the original halogen content of the feedstock. [ABSTRACT FROM AUTHOR]

The isomerization of n‐hexane to produce mono‐ and di‐branched isomers is an important process for octane enhancement of gasoline. In a fixed bed reactor, packed with MFI catalyst, there is synergy between mixture adsorption equilibrium and intra‐crystalline diffusion. This synergy is best exploited by operating the reactor in a transient manner, whereby the desired products consisting of the branched isomers can be recovered from the exiting gas mixture during the early stages of transience. This strategy essentially results in a combination of reaction and separation in a single fixed bed device. [ABSTRACT FROM AUTHOR]

Biofilm processes are increasingly being recognized for the removal of organics and nutrients in domestic wastewater treatment. One system that is often used is the Fixed-Bed Reactor (FBR). This review aimed to analyze wastewater treatment using anoxic-aerobic FBR system with various supporting media. The method used was the descriptive analysis of articles obtained from Google Scholar, ScienceDirect, and Springer. The results of the review showed that wastewater treatment with a growth system is able to remove organics and nutrients quite high. The types of polymers used as supporting media for attaching biofilms consisted of PET, PS, HDPE, and LDPE. However, when viewed from the removal efficiency, the supporting media with polymers is superior to PET compared to other types. This is because PET has hydrophobic physicochemical properties which have good adhesion in the initial attachment of microorganisms. In addition, this type of PS polymer also has fairly high organic and nutrient removal efficiency, similarly to other types of polymers such as HDPE, and LDPE. [ABSTRACT FROM AUTHOR]

We study the non-turbulent pipe flow of a Newtonian fluid through a confined porous medium made of randomly arranged spherical particles in the situation where the ratio between the pipe diameter over the particle diameter (D/d) is less than 10. Using experiments and numerical simulations, we examine the relation between the flow rate and the mean pressure gradient as a function of the Reynolds number and particle size, and how it is affected by the presence of the walls. We investigate the intrinsic variability of the measurements in relation to the randomness of the particle arrangement and how such variability is linked to spatial fluctuations of pressure within the bed. We observe that as D/d decreases, the pressure gradient presents a stronger variability, particularly in relation to where measurements are taken within the pipe. The study also quantifies the difference between measuring the pressure drop at the wall versus averaging over the entire volume, finding a small difference of 2.5 % at most. We examine how the mean pressure gradient is affected by the lateral walls, finding that the pressure drop follows a consistent 1/Re scaling regardless of the confinement of the bed. Finally, we observe that the pressure gradient balances the force exerted on the solid spheres with a very weak contribution of the wall friction, showing that the role of confinement corresponds to a global effect on the bed arrangement which in turns affects the mean pressure gradient. [ABSTRACT FROM AUTHOR]