Catalytic Cracking Research Articles

Catalytic Cracking of Liquefied Petroleum Gas (LPG) to Light Olefins Using Zeolite-based Materials: Recent Advances, Trends, Challenges and Future Perspectives.

The catalytic cracking of liquefied petroleum gas (LPG) has attracted significant attention due to its importance in producing valuable feedstocks for the petrochemical industry. This review provides an overview of recent developments in zeolite-based catalyst technology for converting LPG into light olefins. Catalytic cracking utilizes zeolite-based catalysts usually associated with stability challenges, such as coking and sintering. The discussion focused on the underlying mechanisms that govern the catalytic cracking process and provided insights into the complex reaction pathways involved. A comprehensive analysis of various strategies employed for improving the effectiveness of zeolite catalysts has been discussed in this review. These strategies encompass using transition metals to modify catalyst properties, treatments involving phosphorous modification, alkaline earth metals, and alkali metals to alter the acidity level of the zeolites. The elucidation of the impact of silica-to-alumina ratios in zeolites and the development of hierarchical zeolite-based catalysts through top-down and bottom-up methodologies are also discussed.

Cr6+ Loaded Lewis Acidic Sn‐Beta Zeolites as Reusable Catalysts for Selective Production of Light Olefins via Polyolefin Cracking

AbstractCatalysts for the selective recovery of light olefins from polyolefins should be developed to save limited fossil resources. It is previously revealed that Brønsted acid‐free Sn‐Beta zeolites selectively produced light olefins from polyolefin cracking. Brønsted acid sites ionize olefins by protonation and the generated carbenium ions are converted into other hydrocarbons via various reactions, thereby the elimination of their effects led to the improvement of light olefin production ability. However, the deactivation of zeolites by coke deposition is a critical problem for industrialization. Inhibition of coking deactivation is previously achieved by doping Cr6+ species connected to silanol groups in zeolites. This work aimed to inhibit coke deposition and realize selective and continuous production of light olefins through repetitive polyolefin catalytic cracking. Sn‐Beta zeolites are prepared with various crystallinity by changing the feed fluoride ions content in their synthesis and found that their activity on low‐density polyethylene (LDPE) cracking strongly depended on the feed F/Si ratios, implying the active sites for polyolefin cracking are Lewis acidic open‐Sn sites. Moreover, Cr6+‐doped Sn‐Beta zeolites showed over 45% light olefin yields even in the third LDPE cracking test, although excess Cr adding led to reduce the catalytic activity of Sn‐Beta zeolites.

Integrated Hybrid Modelling and Surrogate Model-Based Operation Optimization of Fluid Catalytic Cracking Process

Fluid Catalytic Cracking (FCC) is one of the most important conversion processes in oil refineries, widely used to convert high-boiling, high-molecular-weight hydrocarbon components from crude oil into more valuable products like gasoline and diesel. Advanced simulation and optimization technologies are critical for improving the operational efficiency and economic performance of the FCC process. First-principles-based simulators rely on parameter estimation and are computationally intensive, making them unsuitable for online optimization. In recent years, with the development of deep learning, data-driven models have made significant progress in FCC modeling. However, due to their black-box nature and difficulty with extrapolation, they are rarely used for optimization. To bridge this gap, we propose an integrated framework that combines hybrid modeling and surrogate model-based optimization. This approach combines plant and simulation data to train a multi-task learning prediction model, which then serves as a surrogate for operational optimization. Validated on a large-scale FCC unit in southern China, the model predicts product yields with an error margin of under 4.84% for all products. Following optimization, yields of LNG, gasoline, and diesel rose by an average of 0.10 wt%, 1.58 wt%, and 1.05 wt%, respectively, resulting in a 3.67% increase in product revenues. This highlights the substantial potential of this framework for industrial applications.

Saturate Acts as Both a “Lubricant” and an “Activator” during the Conversion Process of Mesophase in Fluid Catalytic Cracking Slurry Oil

Saturate Acts as Both a “Lubricant” and an “Activator” during the Conversion Process of Mesophase in Fluid Catalytic Cracking Slurry Oil

TEMPO-Assisted Thermal and Catalytic Cracking of 3-Carene and JP-10 to Produce Low-Molecular-Weight Hydrocarbons

TEMPO-Assisted Thermal and Catalytic Cracking of 3-Carene and JP-10 to Produce Low-Molecular-Weight Hydrocarbons

Electron-beam irradiation of ZSM-5 catalyst with a designed sample holder: Simulation and experiment

A sample holder has been designed to achieve the uniform absorbed-dose distribution in electron-beam (EB) irradiated ZSM-5 catalyst. Simulated results, without considering the holder’s rotation, demonstrated that the holder configuration should be a cylinder hollow, while its dimensions are recommended to be 10–14 cm in outer radius, 7–8 mm in thickness, and 50–54mm in height. The holder’s rotational contribution to the simulated results was estimated to be less than 1%. An actual holder was fabricated based on this design. Steamed ZSM-5 catalyst (∼32 g) was used to verify the catalytic cracking performance of the sample under EB irradiation. The irradiating experiment was conducted using the fabricated holder, with the 10 MeV EB and a fluence of 8×1014 e.cm−2 (257 kJ). The catalytic cracking experiments indicated that most catalytic productions strongly increased with low heavy cycle oil (HCO) yield when irradiated ZSM-5 was used instead of steamed non-irradiated sample. Excellent increases were simultaneously found, for the first time, for propylene (∼24%) and gasoline (∼15%) productions. Irradiated sample also exhibited superior stability compared to non-irradiated one.

Catalytic cracking of methane to H2 and carbon over hydrotalcite-derived sintering-resistant NiVAl catalysts

Catalytic methane cracking produces pure H2 and high value-added carbon, a potentially environmentally friendly process for hydrogen production, but challenges remain in the designing of high-performance catalysts. NiVAl catalysts were obtained by reducing the hydrotalcite precursor, and the samples were analyzed by XRD, ICP, N2 adsorption-desorption, SEM, XPS, and the impacts of reaction temperature and V/Ni ratio on the production of H2 by cracking methane were studied. The results showed that the V doping could promote the reduction of Ni species, improve the specific surface area of the catalyst and inhibit the sintering of Ni particles. The methane cracking hydrogen yield curve illustrates that the performance of NiVAl catalyst shows a volcanic relationship with the V/Ni ratio. The Ni2.4V0.6Al catalyst exhibits optimal performance, with a stable hydrogen yield of about 80% for 210 min at 700 °C. In addition, the reaction temperature also significantly affects the catalyst performance, with high temperatures favoring increased catalytic activity and low temperatures tending to improve stability. The Ni2.4V0.6Al catalyst was reacted at 600 °C for 300 min with 68% hydrogen yield without deactivation.

Integrated physical safety–cyber security risk assessment based on layers of protection analysis

The extensive application of information technology in process industries has increased production efficiency but has also introduced new risks. Therefore, it is necessary to systematically analyse the risks within factories to ensure the stable operation of their production systems. This study proposes an integrated risk assessment method based on layers of protection analysis (LOPA), which combines physical safety and cyber security analyses to provide comprehensive risk assessments for the process industry. The method first identifies the hazardous scenarios and protection layers relevant to a process facility. It then identifies potential cyberattack types and existing countermeasures. Subsequently, the functional impacts of attacks on protection layers and potential coupling relationships are discussed. Using common vulnerability scoring system (CVSS) and semi-quantitative methods, the probability of attack is determined to optimize the probability of failure on demand (PFD) of the protection layers. Finally, a case study of a steam separator in a catalytic cracking unit is used to quantitatively explore the potential attacks and risks of coupled protection layers. The application of Bayesian network (BN) is used for further validation of the method. This study offers a novel quantitative tool for risk assessment in the process industry, which can enhance the security and reliability of industrial production and control systems.

Effects of nickel-deactivations on zeolites-Y of different SiO2/Al2O3 ratios in catalytic cracking of hydrocarbons

Effects of nickel deactivation on catalytic activities of three types of zeolites-Y (Y-5.1, USY-5.2, and VUSY-12) with varying SiO2/Al2O3 ratios were studied in cracking of hydrocarbons. Physicochemical characteristics such as crystalline phases, Ni oxidation states, morphology, acidity, surface area, and thermal stability of the samples were analysed. XRD revealed the absence of observable nickel compounds below 5 wt%, with NiO phase emerging at higher concentrations. Surface areas decreased from 826 to 615 m2/g (Y-5.1), 786–686 m2/g (USY-5.2), and 762–571 m2/g (VUSY-12) at 30 wt% Ni. The total acid sites also reduced from 17.247 to 9.826 µmol/g (Y-5.1), 15.464–8.854 µmol/g (USY-5.2), and 7.094–4.876 µmol/g (VUSY-12). XPS confirmed Ni2+ states. Catalytic cracking tests using n-Heptane demonstrated increases in C5-C6 alkanes, olefins, hydrogen, and methane yields as nickel concentration increased, with respective values of 64 %, 28 %, 79 % and 68 % for Y-5.1; 62 %, 28 %, 76 %, and 62 % for USY-5.2; and 58 %, 21 %, 75 %, and 60 % for VUSY-12. A corresponding decrease in heavier components were observed. The study demonstrates that nickel modification significantly impacts the physicochemical properties and catalytic performance of zeolite-Y and these depend strongly on the SiO2/Al2O3 ratios. The study gives further insights into the structural and catalytic modifications induced by nickel doping in zeolites, highlighting the potential of nickel-modified zeolites in promoting undesirable hydrogen and gas.

Preparation of Novel Hierarchical Catalysts by Simultaneous Generation of β-Zeolite and Mesoporous Silica for Catalytic Cracking.

The gel skeletal reinforcement (GSR) method was applied at the preparation stage of β-zeolite to prepare a novel hierarchical catalyst. A solution of hexamethyldisiloxane (HMDS) and acetic anhydride, a GSR reagent, was added to the mixture of colloidal silica, sodium aluminate, tetraethylammonium hydroxide, sodium hydroxide and water, and successive aging and hydrothermal treatment gave microporous β-zeolite surrounded by mesoporous silica like core-shell structure. Its properties were characterized by XRD, nitrogen adsorption and desorption, NH3-TPD, TEM, and TG-DTA measurements, and further characteristics of the catalysts produced were clarified by the catalytic cracking of n-dodecane. The hierarchical structure of microporous zeolite and mesoporous silica was shown from GSR-2.9HS-H-Beta to GSR-3.2HS-H-Beta, where the molar ratio of HMDS and silica source of β-zeolite was 2.9~3.2 : 100. It was found that in the catalytic cracking of n-dodecane, the relative activity (the conversion per the amount of zeolite crystals) increased with the increase in mesopore volume and surface area. The result indicated that the introduction of mesopores was effective even in catalytic cracking of small molecule of n-dodecane.

Valorization of carbonaceous co-product obtained from iron ore-catalyzed methane cracking as support for Pd catalysts in toluene hydrogenation reaction

Iron ore has been proven as an abundant and sustainable catalyst in the production of hydrogen by catalytic cracking of methane. One of the main challenges is the identification of suitable market niches for the utilization of the resulting iron-carbon hybrid in order to make this process economically viable. This study examines the feasibility of using the iron-carbon hybrid obtained from methane cracking as support of Pd catalysts for the hydrogenation of toluene (350 ºC, 35 bar of H2 at room temperature and 90 min). Before supporting Pd, Fe-C hybrid was subjected to different acid functionalization treatments (nitric and/or phosphoric acids). The results indicate that sequential oxidation with nitric acid, followed by phosphoric acid, is the most effective strategy for achieving the highest catalytic activity (1294 mmolToluene gPd⁻¹) and conversion (27 %). Toluene conversion was 1.8 and 14.2 times higher than with the catalysts treated with nitric and phosphoric acid separately. Therefore, this work proves the possibility of employing carbon/Fe hybrid materials obtained in iron ore catalyzed methane cracking as catalytic supports in industrial relevant reactions.

On‐Purpose Production of Light Olefins Through Oxidative Dehydrogenation: An Overview of Recent Developments

AbstractProducts made from light olefins play an important role in our daily lives. Traditional light olefins production based on steam cracking and fluid catalytic cracking suffer from high energy consumption and CO2 emissions. Thereby, the continually increasing demand for light olefins needs to be met through more environmentally sustainable procedures. On‐purpose production routes are preferred choice among petrochemicals manufacturers, being energy efficient and having lower carbon footprint. Among them, oxidative dehydrogenation (ODH) of light paraffins is a thermodynamically favourable exothermic process as compared to non‐oxidative routes. They can be operated at lower temperatures and have propensity of low coke deposition on catalyst, thereby resisting rapid catalyst deactivation. Herein, we have analysed various catalytic systems utilised in the oxidative dehydrogenation process. We have reviewed role of support, chemical composition of catalyst, presence of dopant, oxidation state of active metal, controlled surface modification by oxidative and reductive pretreatments, and reaction factors for each system. The performance of various catalytic systems for ODH of ethane, propane and butane in the presence of O2, CO2, N2O and special oxidants have been reviewed. A short critical overview on emerging on‐purpose routes for the production of renewable 1,3 butadiene has also been discussed.

Research on Catalytic Pyrolysis Process of Coconut Coat of Tropical Agricultural and Forestry Wastes

The effects of reaction temperature, reaction time, heating rate, nitrogen flow rate, and catalyst quality on the oil yield and oxygen content in oil were investigated by using the single-factor principle. Too high and too low reaction temperature, nitrogen flow rate, heating rate, and reaction time improved the yield of bio-oil, but the oxygen content in bio-oil was higher. The reduction in catalytic dose is beneficial to the increase in oil yield but not conducive to the increase in aromatic compound content. The optimal reaction conditions were observed as a reaction temperature of 500 °C, a nitrogen flow rate of 110 mL/min, a heating rate of 20 °C/min, a reaction time of 15 min, a mass ratio of catalyst to coconut coat powder of 1, an oil yield of 4.97%, a water yield of 35.80%, and a solid yield of 30.78%. The gas yield was 28.45%, the oxygen content was 10.3%, and the aromatic compound content was 89.7%. The analysis of the catalytic cracking mechanism shows that most of the oxygen-containing compounds in bio-oil are generated into water and aromatic compounds by a catalytic cracking reaction at high temperature, thus removing oxygen.

Recycling of a spent residue-fluid-catalytic cracking catalyst into an adsorbent for the removal of copper(II) ions from wastewater

The recycling of spent residue fluid catalytic cracking (RFCC) catalysts into adsorbents addresses both waste management and environmental pollution. Herein, we aimed to extract metals from spent RFCC catalysts, subject them to hydrothermal treatment and washing processes, and characterized by XRD, FT-IR, XPS, BET and SEM techniques, which also evaluating their efficiency as adsorbents. The spent RFCC catalyst was washed for 3 h and hydrothermally treated at 100 °C for 24 h, resulting in RFCC-A with a surface area of 81.77 m²/g and an average diameter of 66.81 nm, the cation-exchange capacities of up to 4300 – 5325 meq/100 g. The washing process removed 40 % – 46 % of vanadium and 12 % – 13 % of nickel. The derived adsorbent demonstrated a Cu(II) ion removal capacity of 120 mg/g from wastewater within 1 h at pH 4, and a total adsorption capacity of 831.68 mg/g after three regenerations. The primary removal mechanism was cation exchange involving electrostatic attraction. The manufacturing cost of the adsorbent was 59.5 USD/kg, equating to 0.50 USD/g Cu(II), with regeneration costs under 1 USD/g Cu(II). These findings indicate that using spent RFCC catalyst-derived adsorbents is cost effective and environmentally beneficial.

Application ICP-OES to Multielement Analysis on Plastic Waste and Blends with Vacuum Gas Oil: Developing a Sample Preparation Protocol

This paper introduces a new methodology for a routine metal analysis of plastic waste (PW) and PW blended with petroleum feedstock such as vacuum gas oil and VGO (PW/VGO). For such purposes, recycled polyethylene and polypropylene plastic were selected to mimic the potential feeds to be integrated at the Fluid Catalytic Cracking unit (FCC) to produce valuable products. Elements such as P, Ca, Al, Mg, Na, Zn, B, Fe, Ti, and Si were included in the method development. Different sample preparation methods were evaluated, such as microwave-assisted acid digestion (MWAD) and dry/wet ashing, followed by a fusion of the ash with lithium borate flux. Some PW homogenization pretreatments, such as cryogenic grinding and hot press molding, were also covered. The finding of this work suggests that MWAD with HNO3 and H2O2 is adequate for both types of samples and is the quickest sample preparation; however, the sample needed to be homogenized, and recoveries for Si and Ti may be biased for PW due to the limited solubilities of these elements in the nitric acid media. Carbon removal is required before fusion sample preparation and analysis due to the amount of carbon in PW samples. The sample needed to be homogenized for wet ash fusion but not for the pre-ash (dry) method. A benefit to the damp ash pretreatment is that the ash for the sample was created in the same crucible used for fusion digestion, avoiding material loss during sample management. Fusion from wet ash or carbon removal allowed for better acid solubility for Si and Ti in PW. The results of the PW samples evaluated matched well with those of both sample preparation methodologies. For most elements, precision was <10% regardless of the sample preparation; however, Fe and P had some variation using wet ash fusion, possibly due to contamination in an open digestion system or variation due to being close to the method limit of quantification (LOQ). The methodology reported here is robust enough to be implemented as routine analysis in any laboratory facility.

Exploring the Morphological Effect of Zeolite Beta on Catalytic Cracking of Polyethylene.

Two types of zeolite catalysts, namely, nanosized Beta-N and micrometer-sized Beta-M, were used to crack low-density polyethylene (LDPE) with three different molecular weights: 4000, 200,000, and 3,000,000. The structural and acidic properties were analyzed by N2 physisorption, transmission electron microscopy, X-ray diffraction, temperature-programmed desorption of isopropylamine (IPA-TPD), and pyridine-adsorbed FTIR. The catalytic activity was tested at 623 K and 3.5 N2 MPa in an autoclave batch reactor for PE cracking. High Mw PE required higher decomposition activation energy due to transfer limitation. Beta-N showed better activity in PE cracking than Beta-M, with PE conversion of 82.7 and 62.0% for Beta-N and Beta-M, respectively. In addition, the nanosized Beta-N exhibited quite lower activation energy of catalytic PE decomposition than Beta-M, obtained by the Kissinger method in TGA measurement. The characterization results demonstrated that the Beta-N has abundant interparticulate mesopores to provide better dispersion for the catalysts into PE melt and the proximity of the cracking active sites. These results revealed that the Beta-N catalyst shows superior activity for the cracking of polyolefins.

Synthesis of furan resin-based mesoporous carbon spheres and application in EDC catalytic cracking

Synthesis of furan resin-based mesoporous carbon spheres and application in EDC catalytic cracking

Selective catalytic conversion of model olefin and diolefin compounds of waste plastic pyrolysis oil: Insights for light olefin production and coke minimization

The primary challenges in ex-situ catalytic pyrolysis of plastic waste to produce light olefins lie in the selective conversion of larger olefins and diolefins downstream of the pyrolyzer. Hence, the catalytic cracking mechanism of plastic pyrolysis oil was explored using an α-olefin (1-decene) and a diolefin (1,9-decadiene) model compounds over an HZSM-5 zeolite-based catalyst in a fixed-bed reactor. Key objectives were to elucidate the reaction pathways for light olefin production, aromatization, and coke formation in catalytic cracking of larger olefins and diolefins. The investigation explored the impact of HZSM-5 steam treatment severity, contact time (∼58–226 ms), and reaction temperature (250–450 °C) on product yields. The severity of steam treatment was found to increase the 1-decene isomerization rate while decreasing the cracking rate and conversion of 1-decene to C3-4 light olefins. In the catalytic cracking of 1-decene, major product types included olefins (linear and nonlinear) and a few naphthenes, while in the case of 1,9-decadiene catalytic cracking, non-linear olefins were absent, with abundant naphthenes followed by lighter diolefins and C3-5 linear olefins. Temperature and contact time variations revealed that the catalytic cracking of 1-decene initiated with double bond rearrangement isomerization, progressing to skeletal isomerization, and intensified cracking reactions producing light C3-4 olefins. Conversely, in the catalytic cracking of 1,9-decadiene, cyclization was the primary reaction pathway, followed by β-scission, resulting in lighter conjugated dienes and light linear olefins. Thermal gravimetric analysis (TGA) of spent catalysts confirmed a higher coke amount generated during 1,9-decadiene cracking compared to 1-decene cracking, indicating that diene compounds serve as precursors for significant coke formation in plastic pyrolysis oil. These insights provide valuable understanding for catalytic upgrading of pyrolysis oil from polyolefin pyrolysis.

Modeling and Numerical Investigations of Flowing N-Decane Partial Catalytic Steam Reforming at Supercritical Pressure

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

Efficient Toluene Decontamination and Resource Utilization through Ni/Al2O3 Catalytic Cracking.

Volatile organic compounds (VOCs), particularly aromatic hydrocarbons, pose significant environmental risks due to their toxicity and role in the formation of secondary pollutants. This study explores the potential of catalytic pyrolysis as an innovative strategy for the effective remediation and conversion of aromatic hydrocarbon pollutants. The research investigates the high-efficiency removal and resource recovery of the VOC toluene using a Ni/Al2O3 catalyst. The Ni/Al2O3 catalyst was synthesized using the impregnation method and thoroughly characterized. Various analytical techniques, including scanning electron microscopy, X-ray diffraction, and N2 adsorption-desorption isotherms, were employed to characterize the Al2O3 support, NiO/Al2O3 precursor, Ni/Al2O3 catalyst, and the resulting solid carbon. Results indicate that Ni predominantly occupies the pores of γ-Al2O3, forming nano/microparticles and creating interstitial pores through aggregation. The catalyst demonstrated high activity in the thermochemical decomposition of toluene into solid carbon materials and COx-Free hydrogen, effectively addressing toluene pollution while recovering valuable resources. Optimal conditions were identified, revealing that a moderate temperature of 700 °C is most favorable for the catalytic process. Under optimized conditions, the Ni/Al2O3 catalyst removed 1328 mg/g of toluene, generated 915 mg/g of carbon material, and produced 1234 mL/g of hydrogen. The prepared carbon material, characterized by its mesoporous structure and high specific surface area graphite nanofibers, holds potential application value in adsorption, catalysis, and energy storage. This study offers a promising approach for the purification and resource recovery of aromatic volatile organic compounds, contributing to the goals of a circular economy and green chemistry.