Search

The FCC unit is closely related to its upstream and downstream units, especially for single series refineries, the change of the working condition of the upstream unit will have a significant impact on the production and operation of the downstream unit. During the catalyst replacement period of the residue hydrogenation unit, the FCC unit blended vacuum residue, resulting in severe deterioration of the properties of the FCC feedstock. The increase in vanadium content in the feedstock led to a decrease in the activity of the equilibrium catalyst and an increase in the olefin content of the FCC gasoline, causing rapid coking of heat exchanger group E101 in the S Zorb unit and affecting its operation. Therefore, during the catalyst replacement period of the residue hydrogenation unit, it is recommended to purchase light paraffin-base crude oil with low sulfur and metal content in advance, in order to alleviate the vanadium poisoning of the FCC unit catalyst; try to increase the catalyst consumption of the FCC unit to over 2.0 kg/t to prevent excessive vanadium content of the equilibrium catalyst; if E101 is rapidly coking and has caused excessive pressure drop, chemical cleaning can be used to clean the coking in the E101 tube pass. [ABSTRACT FROM AUTHOR]

Two sets of Fe-modified Ni/γ-Al 2 O 3 catalysts were prepared and tested in partial oxidation of methane. In one set, Fe was co-impregnated on the surface (NiFe) and in the other set Fe was incorporated in the support bulk (Ni/Fe). The two types showed significantly different coking resistance and performance. While Fe well dispersed in the support bulk significantly enhanced coking resistance, Fe co-impregnated with Ni on the surface enhanced the rate of coke deposition on the catalysts' surfaces. The impact of Fe in the Ni/Fe catalysts is referred to its partially reduced ions (Fe2+) in redox reactions, and to the Ni-support strong interaction retarding the coke formation pathways. On the contrary, carbon formation on the NiFe catalysts is referred to the formation of Ni–Fe alloy particles which may block Ni active sites and can promote cracking of methane as well as CO molecules resulting in higher rates of coking. [Display omitted] • NiFe/γ-Al 2 O 3 and Ni/γ-Al 2 O 3 –Fe were compared in partial oxidation of methane. • Catalysts modified with Fe in the support showed superior coking resistance. • Catalysts with Fe co-impregnated on the surface showed considerable coking. • Coking resistance was referred to redox impact of Fe2+ and Ni-support interactions. • Formation of NiFe alloy and FeAl 2 O 4 in the support enhanced coke formation. [ABSTRACT FROM AUTHOR]

The purpose of this study is to demonstrate the potential of ceramic tile dust (CTD)-derived ZSM-5 zeolite (CZ) and its monodispersed composite with metal oxides (MgO and Fe2O3) in the catalytic pyrolysis of hyphaene thebaica shell (HTS). The HTS was pyrolysed in a Fixed-bed reactor at 400–600 °C, and 100–300 mL/min N2 flowrate. The maximum bio-oil production of 32 % was obtained at 500 °C and 150 mL/min N2 flowrate, with bio-oils containing 50 % acid and octadecenoic acids, as well as esters, phenols, aldehydes, ketones, ethers, aromatics, and hydrocarbons. A carboxymethyl cellulose templating agent was employed for the mesoporous zeolite synthesis from CTD. This resulted in the mesoporous zeolite with a predominant ZSM-5 crystal phase, exhibiting pore diameters ranging from 1.8-6 nm, 229 m2/g surface area and 1145 μmol/g total acidity. The catalytic pyrolysis of HTS was conducted using the ZSM-5 zeolite (CZ) and metal-oxide (MgO, Fe2O3, and Fe2O3/FeO) modified CZ, as monodispersed composite catalysts. Under best thermal pyrolysis conditions, CZ-Fe2O3, CZ-MgO, and CZ-Fe2O3/MgO demonstrated 22–23 % bio-oil yields. Notably, the CZ-Fe2O3/MgO catalyst exhibited the highest hydrocarbon yield at 16 %, while the CZ-MgO favoured the production of phenolics, esters, and alcohols. CZ-MgO also displayed the highest coking level at 7.5 %, indicating faster deactivation than the other catalysts. The synthesised catalysts exhibited remarkable catalytic activity, resulting in a notable improvement in the quality of bio-oils obtained from the intermediate pyrolysis of hyphaene thebaica shells in a fixed-bed reactor.

Thermal conversion of vacuum tower bottoms (VTB) and its narrow‐cut distillation fractions were studied at 530°C between 0.1 and 2 MPa pressure to assess the effect of the reaction pressure on coking. Coke yield in the VTB conversion increased with pressure, which was found to be mostly due to the enhanced coking of the 700°C+ narrow cut. The microcarbon residue in the liquid remained unaffected. The yield of products with a boiling point below 510°C, including distillate and by‐product lights, decreased with the pressure increase. The trend was a cumulative effect of the increased yields from the VTB cuts boiling below 635°C and the decreased yields from the heavier cuts. Admixing different VTB cuts into the VTB feed resulted in the weighted average changes with no synergistic or antagonistic effects. [ABSTRACT FROM AUTHOR]

Since 2018, Shandong Province has successively issued a series of pollution prevention and control programs for air pollutants from the coking industry, which plays a key role in coke production in China. However, a comprehensive assessment of the effectiveness of these measures is lacking. For a better understanding of this issue, based on the published air pollutant emission inventory for the independent coking industry and related policies formulated in Shandong in 2018, this study developed business-as-usual scenarios (BAU-2018, BAU-2025, and BAU-2035) and emission reduction optimization scenarios (ERO-2025 and ERO-2035). The emission reduction potential of PM10, SO2, NOx, PM2.5, and CO2 and their corresponding contributions to Shandong’s air quality with the air quality model (CALPUFF) were assessed under different scenarios. In terms of scenario settings, the gross domestic product of the secondary industry and the coke output of independent coking enterprises were used for linear regression to predict the coke output in 2025 and 2035. The mesoscale atmospheric data model, Weather Research and Forecasting, provided simulated three-dimensional meteorological field data for this study. Regional terrain data (90 m) were obtained from the United States Geological Survey. The resolution of the land use type data was 30 m, according to our previous research results. We adopted the MESOPUFF II chemical mechanism to simulate SO2, NOx, SO42−, NO3−, HNO3, PM10, and PM2.5 pollutants. To ensure the accuracy of the enterprise location information, we examined the enterprise latitude and longitude information one by one using Google Earth location recognition and manual visual inspection. The results showed that in the BAU-2018 scenario, the annual contribution ratios of SO2, NOx, PM10, and PM2.5 in Shandong Province were 0.06%–0.84%, 0.01%–0.63%, 0.04%–0.19%, and 0.07%–0.21%, respectively. Linyi has the highest contribution of SO2 and NOx concentrations to air quality, whereas Jining has the highest contribution of PM10 and PM2.5 concentrations to air quality. Compared with the current scenario (BAU-2018), the emission and contribution concentration of each pollutant showed an alarming decrease in the ERO-2025 scenario. Under the ERO-2035 scenario, the results showed that SO2, NOx, PM10, PM2.5, and CO2 emissions would be reduced by 60.12%, 78.24%, 75.07%, 74.20%, and 37.47%, respectively, compared with those under the BAU-2018 scenario. In the ERO-2035 scenario, the average contribution concentrations of SO2, NOx, PM10, and PM2.5 decreased by 60.74%, 78.56%, 75.00%, and 74.53%, respectively. Moreover, the results of this study showed that the comprehensive implementation of ultralow emission standards in Shandong Province had a considerable impact on air pollutant reduction in the independent coking industry, and the synergistic reduction of air pollutants and carbon dioxide showed huge potential.

This work explored the emission structure, spatial distribution, and uncertainty of the primary PM2.5 emission inventory of 1 km × 1 km anthropogenic sources in Linfen City in 2020 by field research, data acquisition from the municipal departments, and obtaining of activity level data from the statistical yearbook. The reliability and comprehensiveness of the emission inventory were elaborated by comparison and analysis of the results with satellite remote sensing data, China Multiscale Emission Inventory Model (MEIC), and China High-Resolution Carbon and Air Pollutant Emission Database (CHRED 3.0A). The findings reveal that the total primary emissions of anthropogenic sources of PM2.5 in Linfen City are about 26375.7 t, of which road dust sources and iron and steel sources have the largest proportion, 33.5% and 16.1%, respectively. The emission composition of the districts and counties is significantly differentiated, among which approximately 90% come from Houma City process sources, approximately 70% from Jixian County fossil fuel stationary combustion sources, approximately 15% from Pu County biomass combustion sources, approximately 93% from Daining County dust sources, and approximately 13% from Yicheng County mobile sources. The iron, steel, and coking industries in Linfen City emit a total of 6916.9 t of PM2.5, with the largest shares for Quwo County (69.1%) and Xiangfen County (20.81%), where the main sources of pollution in the iron and steel industry come from the sintering and converter processes and those in the coking industry mainly come from the stacks of the coke ovens. The PM2.5 emissions in Linfen City are concentrated in seven districts and counties in the Linfen Basin, and the emission intensity is much higher than the districts and counties with mountainous terrain on both sides, and that in the western districts and counties is lower than that in the eastern districts and counties of Linfen, among which the top 3 by PM2.5 emissions are Quwo County, Houma City, and Xiangfen County; the uncertainty results of different emission sources are between −27.1% and 34.5%. For the total amount of emissions, the PM2.5 emissions in this paper do not differ much from them (MEIC: 30905t; CHRED 3.0A: 19604.3 t; this study: 23498 t); for the spatial distribution, there is a high degree of consistency with the concentration of the remotely sensed inversions, and the high values are concentrated in the Linfen Basin. The iron, steel, and coking industries should further boost the management and monitoring of organized/unorganized emissions and control pollutant emissions from the source and the end.

Abstract Paramos, unique and biodiverse ecosystems found solely in the high mountain regions of the tropics, are under threat. Despite their crucial role as primary water sources and significant carbon repositories in Colombia, they are deteriorating rapidly and garner less attention than other vulnerable ecosystems like the Amazon rainforest. Their fertile soil and unique climate make them prime locations for agriculture and cattle grazing, often coinciding with economically critical deposits such as coal which has led to a steady decline in paramo area. Anthropic impact was evaluated using multispectral images from Landsat and Sentinel over 37 years, on the Guerrero and Rabanal paramos in central Colombia which have experienced rapid expansion of mining and agriculture. Our analysis revealed that since 1984, the Rabanal and Guerrero paramos have lost 47.96% and 59.96% of their native vegetation respectively, replaced primarily by crops, pastures, and planted forests. We detected alterations in the spectral signatures of native vegetation near coal coking ovens, indicating a deterioration of paramo health and potential impact on ecosystem services. Consequently, human activity is reducing the extent of paramos and their efficiency as water sources and carbon sinks, potentially leading to severe regional and even global consequences.

Lake sediment, as a solid waste, can be disposed harmlessly through combustion. The ash melting temperature is an important factor affecting boiler coking and restricting its safe and stable operation. Determining the ash melting temperature after mixing lake sediment with coal is of great significance for achieving the resource utilization of lake sediment. This paper takes the Yunnan Xiaolongtan lignite and the Dianchi Lake sediment as the research objects. The Dianchi Lake sediment is a high moisture solid waste with high nitrogen content and rich heavy metal elements. The Yunnan Dianchi Lake sediment has a large residual stock, mainly generated by a large amount of sediment entering the Dianchi Lake with river water and rainwater. It is the main source of pollution in the Dianchi Lake. However, the Xiaolongtan lignite has problems such as high production, poor coal quality, and high transportation costs, which seriously affect its utilization rate, if the local conditions can be adapted and the problems of high production, difficult treatment, and insufficient efficiency of local sediment can be solved through mixed combustion, in addition to achieving an efficient utilization of lignite, it can also alleviate the local disposal pressure. However, there is currently little research on the blending of lignite with sediment. Through experiments on the ash melting characteristics, the deformation, softening, hemisphere, and flow temperature of ash at a 5%−15% mixing ratio were determined, and the variation law of ash melting point was derived. The mineral composition, oxide, and elemental composition were obtained through XRD, XRF, and SEM-EDS detection and analysis. The crystal structure and mineral composition in the ash were confirmed, and a ternary phase diagram was constructed for thermochemical calculations. The results show that when 5% sediment is mixed, the melting temperature of the ash decreases sharply, and then the downward trend tends to be gentle. The acid-base ratio and silicon aluminum ratio are positively correlated with the downward trend. The oxides of Fe+2, Fe+3, and Ca+2 play a main role in reducing the melting point of the ash, and these oxides are prone to react with refractory minerals to form fluxing minerals such as anorthite and calcium iron pyroxene. During the low temperature stage, Ca oxides mainly promote melting, while during the high temperature stage, Fe oxides act.

Paramos, unique and biodiverse ecosystems found solely in the high mountain regions of the tropics, are under threat. Despite their crucial role as primary water sources and significant carbon repositories in Colombia, they are deteriorating rapidly and garner less attention than other vulnerable ecosystems like the Amazon rainforest. Their fertile soil and unique climate make them prime locations for agriculture and cattle grazing, often coinciding with economically critical deposits such as coal which has led to a steady decline in paramo area. Anthropic impact was evaluated using multispectral images from Landsat and Sentinel over 37 years, on the Guerrero and Rabanal paramos in central Colombia which have experienced rapid expansion of mining and agriculture. Our analysis revealed that since 1984, the Rabanal and Guerrero paramos have lost 47.96% and 59.96% of their native vegetation respectively, replaced primarily by crops, pastures, and planted forests. We detected alterations in the spectral signatures of native vegetation near coal coking ovens, indicating a deterioration of paramo health and potential impact on ecosystem services. Consequently, human activity is reducing the extent of paramos and their efficiency as water sources and carbon sinks, potentially leading to severe regional and even global consequences. [ABSTRACT FROM AUTHOR]

The task of the study was to test new demulsifying compositions for high pyrolysis coal tars originally intended for separating emulsions based on heavy petroleum oils. Coal tars with a specific gravity of 1.243–1.261 were investigated and light coal tar with a specific gravity of 1.185 was used for comparison. Demulsifying compositions for heavy media were prepared on the basis of Dissolvan (Clariant) reagents, "PM" demulsifier was used as a main indicative reagent for breaking of light coal tar emulsions. To determine the efficiency of dewatering a "bottle test" was applied, Fourier transform infrared spectroscopy analysis of the distillate residues was performed to determine the functional group of potential stabilizers. The composition of the mineralized and dispersed solid stabilizers was determined by X-ray fluorescence (XRF) spectrometry. The results showed that for the heavy coal tar emulsions, some compositions based on oxalkylated resin showed high activity and separated up to 17–19% of water, in contrast to the indicative demulsifier 0–3%. An attempt has been made to investigate the mineral composition of emulsion stabilizers transferred into the water part and remaining in the coal tar (sludge). The results of XRF spectrometry suggested that Zn-pyridine compounds are the most likely hydrophile stabilizers of heavy coal tar emulsions. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery 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.)

Metal/biochar catalyst features with the advantages for easy recovery of chemical energy of biochar carrier and metal species via simply combustion. Another unique feature of biochar carrier is intrinsic inorganic species, which might also interact with metal species in resulting catalyst. This was investigated herein by synthesis of the Ni/biochar with rice husk-derived biochar carrier pretreated with NaOH for removal of SiO 2 and evaluation of the resulting catalysts in steam reforming of glycerol. The solid phase reactions between NaOH and biochar (mass ratio: 2) plus subsequent washing removed 94.6% of ash (mainly SiO 2). This formed Ni/biochar of fragmented surface with specific surface area increasing from 207.8 to 457.4 m2g-1 and simultaneously increasing mesopore percentage from 15.5% to 24.0%. NaOH treatment also effectively removed significant portion of both Lewis and Brønsted acidic sites but created abundant alkaline sites. These drastically enhanced nickel dispersion and activity for steam reforming. In-situ IR characterization suggested enhanced adsorption/activation of CO 2 and H 2 O over Ni/biochar treated with NaOH (Ni/biochar-NaOH), which mitigated accumulation of coke precursors bearing C O or C C via accelerated gasification reactions. This led to the reduced amount of coke (mass ratio to catalyst) from 193.4% to 94.7% over Ni/biochar treated with 2-fold of NaOH or to 111.3% over Ni/biochar treated with 1-fold of NaOH. The coke formed was mainly catalytic type in form of carbon nanotube over Ni/biochar-NaOH. The superior resistivity to coking originated from developed pores, enhanced Ni dispersion and abundant alkaline sites from the NaOH treatment. [Display omitted] • NaOH treatment removes SiO 2 in rice husk-biochar and creates developed pores. • NaOH treatment brings abundant alkaline sites while removes Lewis and Brønsted acidic sites. • NaOH treatment enhances Ni dispersion in Ni/biochar and activity for reforming. • NaOH treatment enhances activation of CO 2 /H 2 O, promoting gasification of coke precursors bearing C O/C C. • NaOH pretreatment effectively increases resistivity of Ni/biochar to coking. [ABSTRACT FROM AUTHOR]

Objective The aim is to realize the high-value utilization of CNOOC cycloalkyl vacuum residue. Methods Using the cycloalkyl vacuum residue of CNOOC as raw material, the product distribution and economic benefits of the direct coking process and solvent deasphalting-high pressure hydrogenation-coking combined process were compared. The combined process first used propane as the solvent to perform solvent deasphalting on vacuum residue, which was divided into light deasphalted oil and deoiled asphalt. The light deasphalted oil used a three-stage high-pressure hydrogenation process to produce 150BS bright oil products, and the deoiled asphalt products used a coking process to produce petroleum coke and other petroleum fractions. Results Compared to the direct coking process, the total yield of the liquid product using the combined process was increased by 2.67 percentage points, and the brief economic calculation revealed that the combined process resulted in greater profitability. Conclusions After adopting the combined process, the high-value utilization of vacuum residue can be achieved, and the total yield of liquid products can be increased. [ABSTRACT FROM AUTHOR]

In oil refining, it is a priority to intensify coking. The coking of heavy petroleum residues permits the production of coke with different types of microstructure. That is of great industrial importance. The quality and yield of petroleum coke depend on the composition of the raw materials employed and on the coking conditions. This article describes the functional structure of software that employs statistical analysis of experimental data in the synthesis of polynomial regression models capable of predicting how the yield and microstructure of petroleum coke depend on the coking conditions and the properties of the initial hydrocarbons. The models are verified by using the Fisher test for statistical analysis of calculation results and data derived from a series of experiments conducted by means of the pilot coking plant in the Department of Petrochemical and Coal-Chemical Production Technology at Saint Petersburg State Institute of Technology. Testing at the Institute's world-class laboratory has confirmed the performance of the software and its suitability for research at oil refineries with coking systems. [ABSTRACT FROM AUTHOR]

The article analyzes the reasons for easy coking and blocking in the ebullated-bed residue oil hydrocracking unit. The coking prone areas and typical symptoms of coking in an ebullated-bed residue oil hydrocracking unit of a refinery are introduced. In response to the problem, the optimization is carried out from feedstocks, catalysts, reaction and fractionation conditions and others. Through introducing the purified FCC slurry into the residue oil and dynamically adjusting the residue oil conversion rate to control coking; when processing the residue oil produced from Middle East high sulfur and low nitrogen crude oil, the conversion rate is controlled above 75%; when processing the residue oil produced from Middle East low sulfur crude oil, the conversion rate is controlled at no more than 70%; when processing the residue oil produced from low sulfur and high nitrogen crude oil, the conversion rate is controlled within 65%. The ratio of replacement is con-trolled at 0.90 to 0.95 kg of fresh catalyst per ton of residue; lower control liquid level (25% ~ 30%) at the bottom of vacuum distillate tower, and increase the flow rate of distillate back to the bottom of the tower to reduce coking of asphalt on the bottom wall of the tower. And then, the sediment mass fraction of the bottom oil of the atmospheric tower is stable at less than 0.2%, ensuring the unit long-term stable operation under high residue oil conversion rate. [ABSTRACT FROM AUTHOR]

Various types of raw materials, including plant precursors, coal raw materials, solid fuel combustion residues, coal mining waste, coke fines, and others, are used for the production of porous carbon materials. One important type of porous carbon materials is microporous sorbents, which have a high volume of micropores. These pores provide carbon materials with the ability to effectively adsorb low-molecular-weight gases and possess molecular sieving properties, allowing their use in gas separation processes. The main method of increasing the porosity of sorbents and reducing pore sizes is the activation of sorbents at high temperatures using inert gases. This process increases the activity, capacity, and specific surface area of sorbents. The specific surface area of solid bodies plays a key role in their sorption properties at low and medium pressures. The use of activating agents, such as water vapor, in the thermal treatment processes of carbonaceous materials is a promising method for obtaining porous carbon materials. [ABSTRACT FROM AUTHOR]

The present work is focused on nickel catalysts supported on La2O3-CeO2 binary oxides without and with the addition of Cu to the active component for the dry reforming of methane (DRM). The catalysts are characterized using XRD, XRF, TPD-CO2, TPR-H2, and low-temperature N2 adsorption–desorption methods. This work shows the effect of different La:Ce ratios (1:1 and 9:1) and the Cu addition on the structural, acid base, and catalytic properties of Ni-containing systems. The binary LaCeOx oxide at a ratio of La:Ce = 1:1 is characterized by the formation of a solid solution with a fluorite structure, which is preserved upon the introduction of mono- or bimetallic particles. At La:Ce = 9:1, La2O3 segregation from the solid solution structure is observed, and the La excess determines the nature of the precursor of the active component, i.e., lanthanum nickelate. The catalysts based on LaCeOx (1:1) are prone to carbonization during 6 h spent on-stream with the formation of carbon nanotubes. The Cu addition facilitates the reduction of the Cu-Ni catalyst carbonization and increases the number of structural defects in the carbon deposition products. The lanthanum-enriched LaCeOx (9:1) support prevents the accumulation of carbon deposition products on the surface of CuNi/La2O3-CeO2 9:1, providing high DRM activity and an H2/CO ratio of 0.9. [ABSTRACT FROM AUTHOR]

Hydrogen production from natural gas or biogas, at different purity levels, has emerged as an important technology with continuous development and improvement in order to stand for sustainable and clean energy. Regarding biogas, which can be obtained from multiple sources, hydrogen production through the steam reforming of methane is one of the most important methods for its energy use. In that sense, the role of catalysts to make the process more efficient is crucial, normally contributing to a higher hydrogen yield under milder reaction conditions in the final product. The aim of this review is to cover the main points related to these catalysts, as every aspect counts and has an influence on the use of these catalysts during this specific process (from the feedstocks used for biogas production or the biodigestion process to the purification of the hydrogen produced). Thus, a thorough review of hydrogen production through biogas steam reforming was carried out, with a special emphasis on the influence of different variables on its catalytic performance. Also, the most common catalysts used in this process, as well as the main deactivation mechanisms and their possible solutions are included, supported by the most recent studies about these subjects. [ABSTRACT FROM AUTHOR]

Three γ-Al2O3 supports were prepared by hydrothermal method, and PtSn/Al2O3 catalysts were prepared by sequential impregnation for propane dehydrogenation. The catalyst was characterized by TEM, PXRD, H2-TPR, and other characterization methods. The effects of different morphologies of PtSn/Al2O3 catalysts on the dehydrogenation performance and coking of propane were investigated. The results show that the exposed crystal planes of three morphologies of Al2O3 support are different, which makes the Lewis acid content on the support surface and the interaction of active metals on the support different, thus affecting the catalytic performance of the catalyst and coking carbon. Different morphologies of γ-Al2O3 expose different crystal planes, change the Lewis acid content on the surface of the support, and regulate the interaction between active metals and support, thus affecting propane dehydrogenation performance and catalyst coking. [ABSTRACT FROM AUTHOR]

Purposes Methane dehydroaromatization (MDA) is a frontier topic in the field of natural gas chemical industry. Methods Mo/commercial-HZSM-5, Mo/nano-HZSM-5, and Mo/hollow capsule HZSM-5 were synthesized by using a conventional wet impregnation strategy. The samples were characterized by ICP, XRD, BET, SEM, TEM, NH3-TPD, and XPS, and tested in MDA reaction. The properties of carbonaceous species were measured by TG and TPO techniques. The carbon cycle path was investigated through periodic 12CH4/13CH4 isotope switch pulse experiment over Mo/hollow capsule HZSM-5 catalyst during MDA reaction. Findings The active carbonaceous species located inside the pores could take part in the formation of benzene. Among these three Mo-based catalysts, the Mo/hollow capsule HZSM-5 showed higher CH4 conversion and aromatic yield, as well as superior catalytic lifespan. Compared to Mo/nano-HZSM-5 in zeolite particle size and acidity, Mo/hollow capsule HZSM-5 with lower deactivation rate is attributed enhanced gas molecules diffusion in its hollow capsule structure.

This comprehensive review explores recent catalyst advancements for the hydrodeoxygenation (HDO) of aromatic oxygenates derived from lignin, with a specific focus on the selective production of valuable aromatics under moderate reaction conditions. It addresses critical challenges in bio-crude oil upgrading, encompassing issues related to catalyst deactivation from coking, methods to mitigate deactivation, and techniques for catalyst regeneration. The study investigates various oxygenates found in bio-crude oil, such as phenol, guaiacol, anisole, and catechol, elucidating their conversion pathways during HDO. The review emphasizes the paramount importance of selectively generating arenes by directly cleaving C–O bonds while avoiding unwanted ring hydrogenation pathways. A comparative analysis of different bio-crude oil upgrading processes underscores the need to enhance biofuel quality for practical applications. Additionally, the review focuses on catalyst design for HDO. It compares six major catalyst categories, including metal sulfides, transition metals, metal phosphides, nitrides, carbides, and oxides, to provide insights for efficient bio-crude oil upgrading toward sustainable and eco-friendly energy alternatives. [ABSTRACT FROM AUTHOR]

Coking is still a major cause of catalyst deactivation in catalytic methane reforming processes. In this work, doping the support of Ni/γ-Al 2 O 3 catalysts with iron to provide redox functionality was found to significantly enhance coking resistance in methane partial oxidation. Catalysts with well-dispersed Fe3+ in the support, with Fe mass% in the range of 1.1–15.2 were prepared and tested in reactions at 700 °C. The catalyst with 3.2% Fe in the support showed negligible crystalline carbon at a coking rate of 9.0 × 10−6 g c g−1 catalyst h−1 compared with its Fe-free counterpart that showed a coking rate of 7.7 × 10−4 g c g−1 catalyst h−1. On the other hand, ≥10% Fe resulted in the formation of FeAl 2 O 4 and Fe0 that promoted considerable coking. The unique influence of iron was referred to the role of the dispersed Fe2+, which is dominant upon reduction, in promoting a redox cycle that allow the oxidation and removal of carbon. [Display omitted] • Fe molar concentrations up to 5% gave well-dispersed Fe2+ in reduced alumina. • Molar concentrations of Fe ≤ 5% in the support showed significant coking resistance. • High Fe contents resulted in FeAl 2 O 4 and Fe0 that considerably enhanced coking. • Redox functionality of Fe2+ in the support promoted carbon oxidation and removal. [ABSTRACT FROM AUTHOR]

Fuel flexibility is one of the significant advantages of solid oxide fuel cells (SOFCs). The utilization of methane in SOFCs can not only reduce fuel costs, but also greatly expand its application scenarios, which is of great significance to the commercial development of SOFCs. However, when methane is directly used, Ni-based cermet anode suffers from coking, which seriously affects the durability of the cell. To alleviate the coking issue, a reforming layer outside the Ni-based anode-supporter was proposed in this study, and Ba 0.9 (Zr 0.8 Y 0.2) 1- x Ni x O 3-δ (BZYNi x , x = 0.05, 0.1, 0.15 and 0.2) was used as reforming layer material. Among BZYNi x catalysts, BZYNi 0.2 exhibited excellent catalytic activity toward dry reforming of methane, and methane conversion was as high as 85% at 750 °C. The excellent catalytic durability and coking-resistance of BZYNi 0.2 were also confirmed. When BZYNi 0.2 reforming layer was applied, the single cell fueled with CH 4 –CO 2 fuel showed significantly improved electrochemical performance, durability and coking-resistance. The utilization of BZYNi 0.2 reforming layer provides guidance for solving the coking issue of SOFC cermet anodes when fueled with hydrocarbon. • DRM catalytic activities of BZYNi x with different Ni doping content was explored. • A Ba 0.9 (Zr 0.8 Y 0.2) 0.8 Ni 0.2 O 6-δ reforming layer was added outside the anode support. • Enhanced performance and durability of RSC were observed when fueled with CH 4 –CO 2. [ABSTRACT FROM AUTHOR]

In coal coking, volatile products are liberated. As a result, deposits of pyrocarbon (graphite) are formed on the walls and roof of the coke ovens. Those deposits may obstruct the extraction of coke cake. By identifying the parameters with the greatest effect on the formation of pyrocarbon, its growth in the coke ovens may be more accurately monitored, and hence the coke plant's stock of coke ovens may be better maintained. The influence of the following factors on the rate of pyrocarbon formation is investigated: the metamorphic development of the coal; its moisture content; and its granulometric composition. [ABSTRACT FROM AUTHOR]

Starting from subsurface Zr0-doped “inverse” Pd and bulk-intermetallic Pd0Zr0 model catalyst precursors, we investigated the dry reforming reaction of methane (DRM) using synchrotron-based near ambient pressure in-situ X-ray photoelectron spectroscopy (NAP-XPS), in-situ X-ray diffraction and catalytic testing in an ultrahigh-vacuum-compatible recirculating batch reactor cell. Both intermetallic precursors develop a Pd0–ZrO2 phase boundary under realistic DRM conditions, whereby the oxidative segregation of ZrO2 from bulk intermetallic PdxZry leads to a highly active composite layer of carbide-modified Pd0 metal nanoparticles in contact with tetragonal ZrO2. This active state exhibits reaction rates exceeding those of a conventional supported Pd–ZrO2 reference catalyst and its high activity is unambiguously linked to the fast conversion of the highly reactive carbidic/dissolved C-species inside Pd0 toward CO at the Pd/ZrO2 phase boundary, which serves the role of providing efficient CO2 activation sites. In contrast, the near-surface intermetallic precursor decomposes toward ZrO2 islands at the surface of a quasi-infinite Pd0 metal bulk. Strongly delayed Pd carbide accumulation and thus carbon resegregation under reaction conditions leads to a much less active interfacial ZrO2–Pd0 state.

We present a combined experimental/theoretical study of Pt$_n$/SiO$_2$ andPt$_n$Sn$_x$/SiO$_2$ (n = 4, 7) model catalysts for the endothermicdehydrogenation of hydrocarbons, using the ethylene intermediate as a modelreactant. Supported pure Ptn clusters are found to be highly active towarddehydrogenation of C2D4, quickly deactivating due to a combination of carbondeposition and sintering, resulting in loss of accessible Pt sites. Addition ofSn to Ptn clusters results in the complete suppression of C2D4 dehydrogenationand carbon deposition, and also stabilizes the clusters against thermalsintering. Theory shows that both systems have thermal access to a multitude ofcluster structures and adsorbate configurations that form a statisticalensemble. While Pt4/SiO2 clusters bind ethylene in both di-sigma and pi-bondedconfigurations, Pt$_4$Sn$_3$/SiO$_2$ binds C2H4 only in the pi-mode, withdi-sigma bonding suppressed by a combination of electronic and geometricfeatures of the PtSn clusters. Dehydrogenation reaction profiles on theaccessible cluster isomers were calculated using the climbing image nudgedelastic band (CI-NEB) method.

We present a combined experimental/theoretical study of Pt$_n$/SiO$_2$ andPt$_n$Sn$_x$/SiO$_2$ (n = 4, 7) model catalysts for the endothermicdehydrogenation of hydrocarbons, using the ethylene intermediate as a modelreactant. Supported pure Ptn clusters are found to be highly active towarddehydrogenation of C2D4, quickly deactivating due to a combination of carbondeposition and sintering, resulting in loss of accessible Pt sites. Addition ofSn to Ptn clusters results in the complete suppression of C2D4 dehydrogenationand carbon deposition, and also stabilizes the clusters against thermalsintering. Theory shows that both systems have thermal access to a multitude ofcluster structures and adsorbate configurations that form a statisticalensemble. While Pt4/SiO2 clusters bind ethylene in both di-sigma and pi-bondedconfigurations, Pt$_4$Sn$_3$/SiO$_2$ binds C2H4 only in the pi-mode, withdi-sigma bonding suppressed by a combination of electronic and geometricfeatures of the PtSn clusters. Dehydrogenation reaction profiles on theaccessible cluster isomers were calculated using the climbing image nudgedelastic band (CI-NEB) method.

Starting from subsurface Zr0-doped “inverse” Pd and bulk-intermetallic Pd0Zr0 model catalyst precursors, we investigated the dry reforming reaction of methane (DRM) using synchrotron-based near ambient pressure in-situ X-ray photoelectron spectroscopy (NAP-XPS), in-situ X-ray diffraction and catalytic testing in an ultrahigh-vacuum-compatible recirculating batch reactor cell. Both intermetallic precursors develop a Pd0–ZrO2 phase boundary under realistic DRM conditions, whereby the oxidative segregation of ZrO2 from bulk intermetallic PdxZry leads to a highly active composite layer of carbide-modified Pd0 metal nanoparticles in contact with tetragonal ZrO2. This active state exhibits reaction rates exceeding those of a conventional supported Pd–ZrO2 reference catalyst and its high activity is unambiguously linked to the fast conversion of the highly reactive carbidic/dissolved C-species inside Pd0 toward CO at the Pd/ZrO2 phase boundary, which serves the role of providing efficient CO2 activation sites. In contrast, the near-surface intermetallic precursor decomposes toward ZrO2 islands at the surface of a quasi-infinite Pd0 metal bulk. Strongly delayed Pd carbide accumulation and thus carbon resegregation under reaction conditions leads to a much less active interfacial ZrO2–Pd0 state.

The integrated carbon capture and conversion (ICCC) is a promising catalytic process to produce syngas from CO2 and CH4 via a combined separation and reactor unit. Besides, its performance can fluctuate from the inconsistent feed ratio resulting from the flue gas unit. Herein, the Ratings concept based on density functional theory (DFT) is applied to overcome these problems in a two‐step protocol: (i) catalyst identification, which designates the catalyst characteristics and predicts performance based on reactivity (RT−R) and stability (RT−S) Ratings calculated based on activation energies obtained either from experiments or DFT, and (ii) catalyst optimization that optimized a catalyst's performance via the determination of new operating condition accounted for its deactivation over time. Moreover, temperature and feed ratio sensitivity were investigated, revealing that most catalysts are more sensitive to temperature change than the feed ratio. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery 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.)

Nickel-based catalysts used for dry reforming of methane (DRM) suffer from coking and sintering, which hinders the broad application of the process in the industry. Thermogravimetric analysis was employed to investigate coking on a commercial nickel catalyst with an anti-coking additive (CaO). It was found that the catalyst sintered at temperatures between 850 and 900 °C, which resulted in permanent catalyst deactivation. For the tested Ni/CaO–Al 2 O 3 catalyst, the coking and carbon gasification rates are equal at the temperatures of 796–860 °C, depending on the heating rate (5–20 K/min). Significant differences in the temperatures related to the maxima on TG curves for various heating rates follow from DRM kinetics. This work reveals that the coking rate is lower at higher temperatures. After 50 min, the weight gains amount to about 20% and 40% at 800 °C and 600 °C, respectively. Lower sample weight gains were observed at higher temperatures for a methane decomposition reaction over the Ni/CaO catalyst, unlike for the second tested catalyst – activated carbon. For the nickel catalyst, the reaction order for methane decomposition is 0.6 in the temperature range 640–800 °C, while the sign of the activation energy changes at 700 °C. The elaborated kinetic equation predicts the initial CH 4 decomposition rate with 15% accuracy. [Display omitted] • Thermogravimetric analysis of dry reforming of CH 4 on a commercial Ni/CaO catalyst. • The higher the temperature, the lower the coking rate on the Ni/CaO catalyst. • Reaction order for CH 4 decomposition on the Ni/CaO catalyst is 0.6. • The sign of the activation energy for CH 4 decomposition reaction changes at 700 °C. • Elaborated kinetic equation predicts CH 4 decomposition rate with 15% accuracy. [ABSTRACT FROM AUTHOR]

The present work is focused on nickel catalysts supported on La2O3-CeO2 binary oxides without and with the addition of Cu to the active component for the dry reforming of methane (DRM). The catalysts are characterized using XRD, XRF, TPD-CO2, TPR-H2, and low-temperature N2 adsorption–desorption methods. This work shows the effect of different La:Ce ratios (1:1 and 9:1) and the Cu addition on the structural, acid base, and catalytic properties of Ni-containing systems. The binary LaCeOx oxide at a ratio of La:Ce = 1:1 is characterized by the formation of a solid solution with a fluorite structure, which is preserved upon the introduction of mono- or bimetallic particles. At La:Ce = 9:1, La2O3 segregation from the solid solution structure is observed, and the La excess determines the nature of the precursor of the active component, i.e., lanthanum nickelate. The catalysts based on LaCeOx (1:1) are prone to carbonization during 6 h spent on-stream with the formation of carbon nanotubes. The Cu addition facilitates the reduction of the Cu-Ni catalyst carbonization and increases the number of structural defects in the carbon deposition products. The lanthanum-enriched LaCeOx (9:1) support prevents the accumulation of carbon deposition products on the surface of CuNi/La2O3-CeO2 9:1, providing high DRM activity and an H2/CO ratio of 0.9.

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery 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.)

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry 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.)

Objectives. A characteristic feature of oil production is an increase in the volume of highviscosity bituminous oil. In Russia, technologies based on the use of water vapor are used for their extraction. The use of such technologies leads to a large amount of water in the product stream from the production well. Preparation of oil for processing involves its stabilization, desalination, and dewatering. Since the densities of the extracted oil and the water contained in it are comparable, traditional preparation schemes for processing of high-viscosity bituminous oil are ineffective. One of the possible solutions to the problem involving such oil in the fuel, energy, and petrochemical balance is to use a coking process at the first stage of its processing. This aim can be achieved by studying the influence of the process conditions of coking high-viscosity water-containing oil on the yield and characteristics of the resulting products.Methods. Coking of oil with a density of 1.0200 g/cm3 at 50 °C and with 18 wt % water content was carried out in a laboratory installation in a “cube.” A hollow cylindrical apparatus was used as a reactor and was placed in a furnace. The temperature and pressure in the reactor were maintained at 500–700 °C and 0.10–0.35 MPa, respectively.Results. An increase in the coking process temperature results in an increase in the amount of gaseous products, a decrease in the amount of the coke generated, and a higher dependence of the amount of liquid products on temperature with a maximum yield at 550–600 °C. The process temperature also affects the composition of liquid products. At a lower temperature, the amount of gasoline and kerosene fractions in liquid products is higher. With an increase in pressure, a higher amount of gaseous products, coke, and low-molecular-weight hydrocarbon fractions in liquid products could also be obtained. The characteristics of the coke produced in the coking process are similar to those of commercially produced grades. It is noted that when coking water-containing oil, up to 98% of the emulsion water goes with liquid products, and the remaining amount of water remains in the formed coke.Conclusions. Results showed the possible application of the coking process at the initial stage of processing high-viscosity bituminous oil. In this case, the dewatering stage is significantly simplified since the technological scheme of delayed coking allows the separation of the gasoline fraction from water.

[Display omitted] • An impregnation-complexation method was proposed to selectively control the Ni species. • A systematic identification of dehydrogenation active sites was established based on in situ FTIR experiments. • NiO x /Al 2 O 3 catalysts were developed with high propylene selectivity and low coke yield. Propane dehydrogenation (PDH) is a vital petrochemical process. As an alternative to Pt and Cr-based catalysts, Ni-based catalysts used in PDH, however, exhibit low propylene selectivity with severe coking. This work aims to understand the role of different Ni species in PDH and achieve high propylene selectivity by inhibiting coking. Specifically, we obtained NiO x /Al 2 O 3 catalysts with solely tetrahedrally coordinated Ni2+ (NiIV) by selectively removing microcrystalline NiO x using the impregnation-complexation strategy. The Niσ+ species derived from NiIV exhibited high propylene selectivity (∼88 %) and low coke yield (2.26 %) in PDH. In contrast, reducing microcrystalline NiO x to Ni0 resulted in high methane selectivity and high coke yield (14.90 %). Theoretical calculations and experimental results indicate that this difference is attributed to the faster propylene desorption from Niσ+ as compared to that from Ni0. Therefore, catalysts with well-confined Niσ+ are selective in PDH. This study offers a rational strategy for designing Ni-based PDH catalysts. [ABSTRACT FROM AUTHOR]

Liquid metals are largely unexplored as catalytic media for biomass conversion. Unlike conventional solid-state catalysts which are prone to deactivation, liquid metals, i.e., low-melting metals operated above their melting point, can show resilience against coking, high thermal conductivity, and enhanced liquid-solid contact between catalyst and biomass feedstocks. This promise motivated the present investigation of liquid metals as catalysts for cellulose pyrolysis. Bismuth, tin, and indium were selected as liquid metal candidates, and their impact on cellulose devolatilization kinetics is studied via thermogravimetric analysis. The results indicate that all three metals show catalytic activity, with bismuth catalyzing volatiles formation, while indium and tin enhance char formation. Quantitative analysis of liquid product reveals that bismuth is selective to dehydration and functional rearrangement reactions, leading to anhydro sugars and functionalized furans formation. In contrast, indium and tin are selective towards dehydration, fragmentation reactions, and Diels Alder chemistry, leading to formation of C2-C4 fragments and aromatic compounds, as further confirmed via infrared spectroscopic analysis of the obtained chars. Finally, the Sn and Bi liquid metals' stability against deactivation via coking is examined against conventional solid-state zeolite catalyst through multiple cellulose pyrolysis runs in the thermogravimetric analyzer (TGA) with the same batch of catalyst. While ZSM-5 zeolite catalyst's activity and selectivity declined and approached non-catalytic sand results (both the TGA curve and the liquid product distribution) within the first few runs, both Sn and Bi fairly maintained their robustness against coking for the conducted durability runs. Overall, the results show significant promise for this new class of catalysts for biomass pyrolysis. [Display omitted] • Low-melting liquid metals catalytic activity for cellulose pyrolysis was explored. • Bismuth is selective towards dehydration and isomerization reactions. • Tin and indium catalyze reactions that mainly yield in char. • Tin and indium are selective towards C2-C4 fragments and aromatic alcohols. • Unlike solid catalysts, liquid metals show robustness against coking deactivation. [ABSTRACT FROM AUTHOR]

• TGA and GC enable complementary studies of catalytic decomposition of CH 4 (CDM). • Thermal (non-catalytic) decomposition of CH 4 presents a significant source of H 2. • Reaction order with respect to CH 4 is 0.6 for CDM on the investigated Fe/C catalyst. • Activation energy is approximately 71 kJ/mol for CDM on the investigated catalyst. • Repeated regeneration of the Fe/C catalyst with CO 2 does not cause its deactivation. Methane pyrolysis (MP) is one of enabling technologies in the economy transition from fossil to renewable fuels. Although the technology has its undoubted advantages, the cost of producing hydrogen with MP is still higher than that using Steam Methane Reforming (SMR). Remote and contactless catalyst heating by microwaves can significantly intensify methane pyrolysis and reduce these costs. One of the catalysts that can be utilized in the microwave-assisted MP is the Fe/C catalyst. The current work presents a reference study of the MP kinetics on the dedicated Fe/C catalyst under conventional (non-microwave) heating. The kinetic data determined in this work are necessary for appropriate modelling and design of the microwave-assisted MP reactor. Experiments were carried out using thermogravimetric analysis coupled with gas chromatography. The reaction order with respect to methane and the activation energy were found to be 0.6, and 71 kJ/mol, respectively. The effects of CO 2 concentration and temperature on the regeneration of the catalyst were also demonstrated. [Display omitted] [ABSTRACT FROM AUTHOR]

This comprehensive review explores recent catalyst advancements for the hydrodeoxygenation (HDO) of aromatic oxygenates derived from lignin, with a specific focus on the selective production of valuable aromatics under moderate reaction conditions. It addresses critical challenges in bio-crude oil upgrading, encompassing issues related to catalyst deactivation from coking, methods to mitigate deactivation, and techniques for catalyst regeneration. The study investigates various oxygenates found in bio-crude oil, such as phenol, guaiacol, anisole, and catechol, elucidating their conversion pathways during HDO. The review emphasizes the paramount importance of selectively generating arenes by directly cleaving C–O bonds while avoiding unwanted ring hydrogenation pathways. A comparative analysis of different bio-crude oil upgrading processes underscores the need to enhance biofuel quality for practical applications. Additionally, the review focuses on catalyst design for HDO. It compares six major catalyst categories, including metal sulfides, transition metals, metal phosphides, nitrides, carbides, and oxides, to provide insights for efficient bio-crude oil upgrading toward sustainable and eco-friendly energy alternatives.

The switch from a carbon-based to a hydrogen-based economy requires environmentally friendly methods for hydrogen production. CO2-reforming of methane promises to be a greener alternative to steam-methane reforming, which accounts for the majority of hydrogen production today. For this dry process to become industrially competitive, challenges such as catalyst deactivation and degradation through coke formation must be better understood and ultimately overcome. While bulk characterisation methods provide a wealth of useful information about the carbon formed during coking, spatially resolved techniques are required to understand the type and extent of degradation of supported catalyst particles themselves under coking conditions. Here, lab-based X-ray nano-computed tomography, in conjunction with a range of complementary techniques, is utilised to understand the effects of the nickel-to-cobalt ratio on the degradation of individual supported catalyst particles. Findings suggest that a bimetallic system greatly outperforms monometallic catalysts, with the ratio between nickel and cobalt having a significant impact on the type and quantity of the carbon formed and on the extent of supported catalyst breakdown.

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery 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.)

Surface carbon deposits deactivate Ni and Co catalysts in reactions involving hydrocarbons and COx. Electronic properties, adsorption energies of H, C, and CHx species, and the energetics of the hydrogenation of surface C atom to methane are studied for (100) and (111) surfaces of monometallic Ni and Co, and bimetallic NiCo. The bimetallic catalyst exhibits a Co→Ni electron donation and a concomitant increase in the magnetization of Co atoms. The CHx species resulting from sequential hydrogenation are more stable on Co than on Ni atoms of the NiCo surfaces due to more favorable (C-H)–Co agostic interactions. These interactions and differences between Co and Ni sites are more significant for (111) than for (100) bimetallic surfaces. On (111) surfaces, CH is the most stable species, and the first hydrogenation of C atom exhibits the highest barrier, followed by the CH3 hydrogenation steps. In contrast, on (100) surfaces, surface C atom is the most stable species and CH2 or *CH3 hydrogenations exhibit the highest barriers. The Gibbs free energy profiles suggest that C removal on (111) surfaces is thermodynamically favorable and exhibits a lower barrier than on the (100) surfaces. Thus, the (100) surfaces, especially Ni(100), are more prone to C poisoning. The NiCo(100) surfaces exhibit weaker binding of C and CHx species than Ni(100) and Co(100), which improves C poisoning resistance and lowers hydrogenation barriers. These results show that the electronic effects of alloying Ni and Co strongly depend on the local site composition and geometry. [ABSTRACT FROM AUTHOR]

The role of Cu:Co composition in bi‐metallic Cu‐Co/ZnAl2O4 catalysts on higher alcohol synthesis (HAS) was investigated at H2:CO = 4. The addition of Cu strongly facilitated Co reduction upon catalyst activation and suppressed coke deposition during HAS. Formation of predominantly hydrocarbons and higher alcohols was observed on the bi‐metallic catalysts. Co/ZnAl2O4 produced mainly CH4 and Cu/ZnAl2O4 mainly CH3OH, while at Cu:Co = 0.6 the best ethanol selectivity of 4.5 % was reached. The microstructure of the spent catalysts confirmed a close interaction of Cu and Co. [ABSTRACT FROM AUTHOR]

A method is proposed for producing coke from distilled coal tar fractions. The influence of heat treatment of the tar fractions on the coke yield is investigated. The physicochemical characteristics of the coke produced from the tar fraction boiling above 280°C are investigated. [ABSTRACT FROM AUTHOR]

Summary: The thermal cracking characteristic of an in‐house prepared plant‐derived hydrogenated carene (H‐Carene) fuel is examined above its critical temperature and pressure. The experiments were performed for a wide range of temperatures between 450°C and 650°C at 40 bar pressure in a tubular flow reactor. At 650°C and 40 bar pressure, the conversion of the H‐Carene fuel is about 40%, and the estimated value of chemical heat sink capacity is 488 kJ/kg of fuel. The aptness of triethylamine (TEA) as an initiator to improve the heat sink capacity of the H‐Carene fuel is also examined. The investigation showed that the initiator improved the fuel conversion and endothermicity. The endothermic heat sink capacity of the H‐Carene increased by about 28% at 650°C with 5% (by weight) of TEA. It is noted that the sensitivity of temperature on the coke formation rate is higher than the initiator sensitivity for a similar range of the conversion change. The thermal cracking of H‐Carene follows a first‐order kinetic model, and the estimated value of the apparent activation energy of the H‐Carene cracking reaction is about 95 kJ/mol. The work shows that the heat sink capability of the plant‐derived H‐Carene fuel is comparable with JP‐7, a petroleum‐derived fuel. Novelty Statement: The manuscript presented the cracking characteristics of hydrogenated carene under supercritical conditions emphasizing various features like detailed characterization, feed conversion, product distribution, cooling capacities, coke deposition rate, cracking kinetics, and so on. It also highlighted the suitability of an amine‐based initiator to enhance the endothermicity of the fuel. The study is unique and not found in any article which addressed the above aspects altogether. [ABSTRACT FROM AUTHOR]

The VO X /Al 2 O 3 is known as an active catalyst in the propane dehydrogenation, however, with poor stability due to the severe coking problem. In this study, the VO X /Al 2 O 3 catalyst was modified by boric acid, and the catalyst exhibited significantly improved stability and less coke deposition than the unmodified counterpart. The experimental results and theoretical modeling (DFT) suggested that the boron decreased the polymerization degree of VO X species, generated a high proportion of isolated vanadium species that reduced the initial activity but enhanced the stability of VO X /Al 2 O 3 catalyst. Boron interacted with Al and V forming B-O-Al and B-O-V bonds, which significantly reduced the amounts of both Brønsted and Lewis acid sites, alleviating the coke deposition rate on the catalyst surface. The boron on VO X /Al 2 O 3 promoted the desorption of propylene that inhibited further cracking and its polymerization, thus improving the propylene selectivity and catalyst stability. [Display omitted] • Boric acid modification improves the stability of the VO X / Al 2 O 3 catalyst. • Boron reduces the VO X polymerization degree and produces isolated vanadium sites. • Boron reduces the number of Brønsted and Lewis acid sites. • Boron promotes the propylene desorption, inhibiting polymerization and cracking. [ABSTRACT FROM AUTHOR]