Catalytic Cracking Catalyst Research Articles

Chemical Recycling of Used Motor Oil by Catalytic Cracking with Metal-Doped Aluminum Silicate Catalysts

The chemical recycling of used motor oil via catalytic cracking to convert it into secondary diesel-like fuels is a sustainable and technically attractive solution for managing environmental concerns associated with traditional disposal. In this context, this study was conducted to screen basic and acidic-aluminum silicate catalysts doped with different metals, including Mg, Zn, Cu, and Ni. The catalysts were thoroughly characterized using various techniques such as N2 adsorption–desorption isotherms, FT-IR spectroscopy, and TG analysis. The liquid and gaseous products were identified using GC, and their characteristics were compared with acceptable ranges from ASTM characterization methods for diesel fuel. The results showed that metal doping improved the performance of the catalysts, resulting in higher conversion rates of up to 65%, compared to thermal (15%) and aluminum silicates (≈20%). Among all catalysts, basic aluminum silicates doped with Ni showed the best catalytic performance, with conversions and yields three times higher than aluminum silicate catalysts. These findings significantly contribute to developing efficient and eco-friendly processes for the chemical recycling of used motor oil. This study highlights the potential of basic aluminum silicates doped with Ni as a promising catalyst for catalytic cracking and encourages further research in this area.

Influences of regeneration atmospheres on structural transformation and renderability of fluidized catalytic cracking catalyst

The regeneration of fluidized catalytic cracking (FCC) catalysts is an essential process in petroleum processing. The current study focused the regeneration reaction characteristics of spent fluidized catalytic cracking catalyst (SFCC) at different atmospheres with influences on pore evolution and activity, for a potential way to reduce emission, produce moderate chemical product (CO), and maintain catalyst activity. The results show that regeneration in air indicates a satisfaction on removing coke on the catalyst surface while giving a poor effect on eliminating the coke inside micropores. This is attributed that the combustion in air led to a higher temperature and further transformed kaolinite phase to silica-aluminum spinel crystals, which tended to collapse and block small pores or expand large pores, with similar results observed in pure O2 atmosphere. Nevertheless, catalysts regenerated in O2/CO2 diminished the combustion damage to the pore structure, of which the micro porosity after regeneration increased by 32.4% and the total acid volume rose to 27.1%. The regeneration in pure CO2 displayed low conversion rate due to the endothermic reaction and low reactivity. The coexistence of gasification and partial oxidation can promote regeneration and maintain the original structure and good reactivity. Finally, a mechanism of the regeneration reaction at different atmospheres was revealed.

Evaluation of high-density cement-based materials (HDCM) for immobilizing spent fluidized catalytic cracking catalysts

Spent fluidized catalytic cracking catalysts (SC) are considered toxic solid waste due to it is contained heavy metal ions, which can be polluting for the environment and harmful to humans. Since conventional disposal methods can be harmful to both the environment and people, therefore, new disposal methods need to be developed. In this study, 80 kg/m3 and 150 kg/m3 of SC are incorporated into the design of high-density cement-based materials (HDCM). The mechanical properties, hydration kinetics, durability, and environmental characteristics of HDCM containing SC are evaluated. The results shown that the HDCM has good mechanical properties, with a 6.62% increase in compressive strength at 28 days for HDCM containing 80 kg/m3 of SC. Furthermore, the HDCM containing SC has better long-term volumetric stability, with a 44.55% reduction in dry shrinkage compared to the reference. Further, the HDCM has a good immobilizing ability for heavy metal ions. The leaching concentrations of Ni and V from C1 are only 0.203 mg/L and 0.282 mg/L, and the immobilizing rate is 99.08% and 98.26%, respectively. For the C2, the leaching concentrations of Ni and V are 0.198 mg/L and 0.402 mg/L, the immobilizing rate is 99.31% and 98.25%.

Organic filler-free synthesis of mordenite molecular sieves using industrial residues

Considering the complex elemental and phase compositions, it is a challenge to realize the high value utilization of solid residues in the preparation unit of fluid catalytic cracking catalysts (i.e., FCCR). The current research proposes a disposal approach of FCCR by a direct transformation from FCCR to mordenite molecular sieves. Species evaluation of FCCR in alkaline fusion activation is investigated. Ageing temperature/ duration, crystalline temperature/ duration, amount of water and silica sol are systematically optimized. Obtained mordenite molecular sieves are pure and highly crystallized. When employed as catalysts for the isomerization of α-pinene, as-synthesized mordenite molecular sieves have a comparable performance with commercial ones due to the low diffusion resistance of hierarchical pore structure. These researches are important as a reference for the utilization of FCCR in the field of zeolitic synthesis.

Optimization and analysis of biomass carbon loaded metal catalyst for catalytic cracking of toluene

The technology of hydrogen production from biomass pyrolysis is on the way, but the biomass tar produced in the process of pyrolysis seriously affects its practical application. The key to catalytic cracking technology was to develop highly low-temperature active and stable catalysts. In view of that, a new anti-sintering carbon-based nanocatalyst with distinct micro-mesoporous structure was synthesized by carbothermic reduction of the catalyst under mixed gas (H2/N2) atmosphere using cigarette stalks as raw material. The results showed that at a relatively low temperature of 700 °C, the catalyst had a high toluene conversion of 100 %, a stable lifetime of 250 min, a maximum hydrogen yield of 12,250 ppm and a desirable hydrogen selectivity of 77 %. The addition of hydrogen during the catalyst synthesis enabled a stronger interaction between the metal and the carbon support, which maintained a high metal distribution, resulting in a more interesting anti-sintering phenomenon of nickel nanoparticles at high temperatures. In particular, hydrogen etching of the support avoided collapse of the pores at high temperatures. At the same time, the etching enriched the pore structure of the support, thus increasing the specific surface area and pore volume of the support. This study provided a simple treatment of a carbon loaded nickel catalyst in the synthesis process and reported a novel low-temperature catalytic cracking catalyst with good toluene cracking activity and hydrogen generation.

Effect of process mode on product yields and selectivity in the catalytic co-pyrolysis of peanut shells and polypropylene using spent fluid catalytic cracking (FCC) catalyst

In this study, mixtures of peanut shells (B) and polypropylene (PP) were co-pyrolyzed in two configurations using spent fluid-catalytic-cracking (sFCC) catalyst. The feed ratio was varied to investigate changes in yields and selectivity. The ex-situ configuration generated a higher-quality liquid, less char and more gas yields (1.3 times on an average) than the in-situ mode. Both the operation modes produced similar aromatic compounds; however, the ex-situ bio-oil had a higher monoaromatic fraction. The ex-situ configuration showed more polycyclic aromatic hydrocarbons at higher B and PP loadings, with a maximum yield of ∼44%C at B: PP ratio of 1:2. The ex-situ mode cracked polypropylene more efficiently to short-chain olefins (<C10). The dominant fractions were C9 and C12 in the in-situ and C9 in the ex-situ mode. Co-pyrolysis improved the net hydrogen content of bio-oil. PP showed better aromatics selectivity than low density polyethylene (LDPE) due to the differences in their branched-chains.

LDPE Film Waste Treatment into Liquid Fuel Using Catalytic Cracking

Plastic industry development has increased the amount of plastic waste, including LDPE plastic film, therefore LDPE waste processing becomes essential, such as thermal or catalytic cracking. Cracking is the breakdown of complex hydrocarbons into simple and commercial hydrocarbons (C3-C40). The catalytic cracking is preferred due to lower temperatures, which is 200-300°C instead of 500-700°C. In this study, catalyst selection, acid impregnation of catalyst, catalyst loading (wt%), N2-gas-purging, feed-to-solvent weight-ratio, temperature, and reaction time were studied to determine the most suitable process condition to obtain the highest liquid fraction. In this study, the catalytic cracking was conducted at 20 bar with kerosene as solvent, with and without N2-gas-purging at several temperatures (265 and 295°C), solvent-to-feed weight-ratios (5:1 and 4:1), catalyst types (bentonite, SiO2 and ZSM-5), catalyst loading (wt%) (1.0wt%; 5.0wt%; 7.0wt%; 9.0wt%; 10.0wt%), and reaction time (1-3 hours). The best results were with N2-gas-purging using 10.0wt%-bentonite in (5:1) solvent-to-feed weight-ratio for 1 hour at 295οC produced 54.9wt% of liquid fraction and without N2-gas-purging at 265°C produced 54.5wt% of liquid fraction, indicating the possibility of N2-gas-purging exclusion in future studies. Additionally, this study has promoted bentonite as a potentially viable catalyst for LDPE plastic waste catalytic cracking.

Nickel-Passivating element selection in FCC process and mechanistic study on the passivation of nickel by lanthanum and phosphorus

Motivated by the dehydrogenation activity of nickel (Ni) and the toxicity of free nickel oxide (NiO) in the fluid catalytic cracking (FCC) catalysts, this study aims to reveal the appropriate elements to in-situ passivate nickel during the cracking reactions of oil by conducting hydrocarbon dehydrogenation tests of Y-zeolite loaded with Ni and passivating elements in a Pyro-probe micro-reactor coupled with GC-TCD and MS. The conditions were chosen as 550 °C with a catalyst-to-hydrocarbon mass ratio of 5:1. Additionally, hydrogen-temperature programmed reduction (H2-TPR) was conducted. In supporting the experimental observation, thermodynamic calculations were also performed to assist the selection of possible Ni-passivating elements in terms of the free Gibbs energy for their reactions with NiO. Lanthanum (La) and phosphorus (P) were found to exert the most effective effects on nickel passivation. The use of twice the quantity of La or P more than Ni, or the combined use of La and P each in equimolar ratio to Ni is able to decrease the dehydrogenation extent by 97%. La can passivate the free NiO species by chemically bonding with NiO which, otherwise, would bond with alumina in zeolite. Instead, P is preferentially coated on the Ni-bearing particles, which leads to the formation of phosphate that is inactive in the dehydrogenation of the model organic compounds when compared to the free NiO.

Optimizing the accessibility of zeolite Y on FCC catalyst to improve heavy oil conversion capacity

Optimizing the accessibility of zeolite Y, the main active component in fluid catalytic cracking (FCC) catalyst, is a crucial strategy to improve the heavy oil cracking performance of FCC catalysts. Four FCC catalysts with different Y zeolite content were prepared via in-situ crystallization method by adjusting the crystallization time. The distribution characteristics of the Y zeolite in in-situ crystallized catalysts have been characterized by scanning electron microscopy (SEM), laser confocal fluorescence microscopy and high-resolution field emission scanning electron microscopy (HR-FESEM). A unique structural feature of the FCC catalysts has been achieved, with the Y zeolite component mainly distributing in the outer layer of microspheres. The results of adsorption rate of macromolecule probes reveal that the appropriate zeolite layer thickness and topology were beneficial to the mass transfer performance and acid accessibility of FCC catalyst. The effective utilization ratios of zeolite in the novel FCC catalysts for heavy oil cracking on advanced catalyst equipment (ACE) is in good correspondence with the mass transfer performance of macromolecules and the accessibility of acid sites. It could be confirmed that the excellent heavy oil conversion performance of a FCC catalyst does not depend on the content of zeolite, but rather on the distribution characteristics are in favor of the accessibility of zeolite components.

Study on synergistic pyrolysis and kinetics of mixed plastics based on spent fluid-catalytic-cracking catalyst

At present, disposable plastic products such as plastic packaging are very common in our daily life. These products are extremely easy to cause serious damage to the soil and marine environment due to their short design and service life, difficulties in degradation, or long degradation cycles. Thermochemical method (pyrolysis or catalytic pyrolysis) is an efficient and environmentally friendly way to treat plastic waste. In order to further reduce the energy consumption of plastic pyrolysis and improve the recycling rate of spent fluid catalytic cracking (FCC) catalysts, we adopt the "waste-to-waste" approach to apply the spent FCC catalysts as catalysts in the catalytic pyrolysis of plastics, exploring the pyrolysis characteristics, kinetic parameters, and synergistic effects between different typical plastics (polypropylene, low-density polyethylene, polystyrene). The experimental results show that the spent FCC catalysts used in the catalytic pyrolysis of plastics are beneficial to reduce the overall pyrolysis temperature and activation energy, in which the maximum weight loss temperature decreases by about 12℃ and the activation energy decreases by about 13%. The activity of spent FCC catalysts is improved after modification by microwave and ultrasonic, which further improve the catalytic efficiency and reduce the energy consumption of pyrolysis. The co-pyrolysis of mixed plastics is dominated by positive synergistic effect, which is conducive to improving the thermal degradation rate and shortening the pyrolysis time. This study provides relevant theoretical support for the resource application of spent FCC catalysts and "waste-to-waste" treatment of plastic waste.

Effects of the FCC catalyst binder type on propylene production during catalytic cracking of VGO

Effects of the fluid catalytic cracking (FCC) catalyst binder type on catalytic properties were studied. SiO2 and Al2O3 were used for the FCC catalysts as a binder. Although the yield of olefins in gasoline, which is easily cracked to light olefins such as a propylene over the ZSM-5 additive, over the SiO2 binder catalyst was lower than that over the Al2O3 binder catalyst during vacuum gas oil (VGO) cracking, however, when the ZSM-5 additive was blended, the SiO2 binder catalyst showed higher propylene yield as compared with the Al2O3 binder catalyst. In terms of the difference in the properties of catalyst, the SiO2 binder catalyst indicated higher SAmicro than the Al2O3 binder catalyst after steaming. Moreover, the acid properties of the FCC catalysts after steaming also were affected by the binder type. In results, the SiO2 binder catalyst indicated higher propylene yield as compared with the Al2O3 binder catalyst.

Study on kinetics of spent FCC catalyst applied to the living waste plastics

AbstractThe thermochemical method is one of the most potential ways to treat waste plastics. In order to reduce the energy consumption of pyrolysis, this study selected spent fluid catalytic cracking (FCC) catalyst as a catalyst for pyrolysis of waste plastics to explore the pyrolysis process of mixed waste plastics (polypropylene (PP)/polyethylene (PE)/polystyrene (PS)). The kinetic calculations show that there was a positive synergistic effect in the co‐pyrolysis of mixed plastics, which was beneficial to the reduction of activation energy. However, the participation of spent FCC catalysts can further reduce the pyrolysis temperature and activation energy of plastics, and increase the thermal degradation rate. Compared with non‐catalytic pyrolysis, the pyrolysis temperature corresponding to the maximum weight loss rate during catalytic pyrolysis was about 12 K earlier, the maximum degradation rate was about 41% higher, and the average activation energy decreased by about 22 kJ/mol. In order to further improve the catalytic efficiency of spent FCC catalysts, the spent FCC catalysts were modified by ball milling or ultrasonic method and then used for plastic pyrolysis. It was found that the modification effect of ball milling method was better than that of the ultrasonic method. Through thermodynamic analysis, it was found that the endothermic reaction occurred in the process of plastic pyrolysis and could not proceed spontaneously. The formed pyrolysis products reduced the disorder of a microscopic system. Combined with the experimental results of this paper, it can provide theoretical support for the catalytic pyrolysis of spent FCC catalysts for mixed waste plastics.

Study on fine powder discharged from hoppers modified with insert

The use of inserts in the hopper provides a reliable way to improve the quality of powder flow. In this work, glass beads, fluidized catalytic cracking catalyst (FCC), lignite and polyvinyl chloride (PVC) were used as experimental materials and the flow properties of powders were characterized by the FT4 powder rheometer and the PT-X powder tester. Discharge experiments on a Perspex hopper at a laboratory scale are presented in this paper, comparing the flow characteristics of fine powders discharged from a plain hopper and from hoppers modified with the use of inserts of different geometries. Effects of insert and powder properties on powder flow rate are discussed. A mechanism model is developed to describe the hindering effect to the discharge consequent to the powder expansion at the hopper outlet. Mechanisms of insert on powder flow are analyzed. It is demonstrated that the higher flow rates of the hopper operating with a solid insert are due to the anticipated expansion of the material generated by the presence of the insert. The hopper with a hollow insert shows a flow sequence and the values for the powder flow rates are averaged values between two regimes. Based on understanding above mechanisms, powder flow rates for plain hopper and hoppers modified with insert are successfully predicted.

Carbon and H2 recoveries from plastic waste by using a metal-free porous biocarbon catalyst

Carbon and H2 recoveries from plastic waste enable high value-added utilizations of plastic waste while minimizing its GHG emissions. The objective of this study is to explore the use of a metal-free biocarbon catalyst for waste plastic pyrolysis and in-line catalytic cracking to produce H2-rich gases and carbon. The results show that the biocarbon catalyst exhibits a good catalytic effect and stability for various plastic wastes. Increasing the C/P ratio from 0 to 2, induce an increase in the conversion rate of C and H in plastics to carbon and H2 from 57.1% to 68.7%, and from 22.7% to 53.5%, respectively. Furthermore, a carbon yield as high as 580.6 mg/gplastic and an H2 yield as high as 68.6 mg/gplastic can be obtained. The hierarchical porous structure with tortuous channels of biocarbon extends the residence time of pyrolysis volatiles in the high-temperature catalytic region and thereby significantly promotes cracking reactions.

Study on the Mechanism and Experiment of Styrene Butadiene Rubber Reinforcement by Spent Fluid Catalytic Cracking Catalyst

Spent Fluid Catalytic Cracking (FCC) Catalyst is a major waste in the field of the petroleum processing field, with a large output and serious pollution. The treatment cost of these waste catalysts is high, and how to achieve their efficient reuse has become a key topic of research at home and abroad. To this end, this paper conducted a mechanistic and experimental study on the replacement of some carbon blacks by spent FCC catalysts for the preparation of rubber products and explored the synergistic reinforcing effect of spent catalysts and carbon blacks, in order to extend the reuse methods of spent catalysts and reduce the pollution caused by them to the environment. The experimental results demonstrated that the filler dispersion and distribution in the compound are more uniform after replacing the carbon black with modified spent FCC catalysts. The crosslinking density of rubber increases, the Payne effect is decreased, and the dynamic mechanical properties and aging resistance are improved. When the number of replacement parts reached 15, the comprehensive performance of the rubber composites remained the same as that of the control group. In this paper, the spent FCC catalysts modified by the physical method instead of the carbon-black-filled SBR can not only improve the performance of rubber products, but also can provide basic technical and theoretical support to realize the recycling of spent FCC catalysts and reduce the environmental pressure. The feasibility of preparing rubber composites by spent catalysts is also verified.

Preparation of the Al13 Sol via Electrodialysis as an Effective Binder of FCC Catalysts

This study presented a clean preparation process of alumina sols via electrodialysis. For the first time, as an effective binder for fluid catalytic cracking catalysts, the Al13-enriched product was found to be easily converted to γ-Al2O3 with a larger BET specific surface area, pore volume, more Lewis acids, Al-OH sites, and lower Cl– content after calcination. A series of spray-dried FCC catalysts were steam-aged and tested by heavy oil cracking. In comparison with the commercial sol-containing FCC catalysts, Al13-containing catalysts exhibited higher accessibility of active centers, mechanical strength, heavy oil cracking ability, and liquid yield.

Attrition characteristics of limestone in gas-solid fluidized beds

Calcium looping is a potential energy-efficient post-combustion CO2 capture process that is competitive with existing commercially available technology like oxy-combustion. The attrition of CaO-based sorbents during alternating calcination/carbonation cycling in calcium looping (CaL) has the potential to escalate operation cost and contribute to environmental emisssions. Here, we measure jet mill attrition rates of four commercial limestones from Ghana and Canada and compare them with fluid catalytic cracking catalyst (FCC) and commercial vanadyl pyrophosphate (VPP) in a jet mill. We assessed the effect of orifice velocity, attrition time and calcination on particle attrition resistance. The attrition rates of the limestones increased exponentially from as low as 2.4 mg h−1, which is an acceptable rate for industrial applications, up to 38 mg h−1, which is prohibitively high as the orifice velocity increased from 180 m s−1 to 230 m s−1. The attrition rates of the FCC and VPP catalyst were somewhat higher at the low orifice velocity (5 5 mg h−1 and 8 mg h−1, respectively) but lower at the high orifice velocity (21 mg h−1−1 and 26 mg h−1, respectively). Within 3 h, Bui and Nauli limestones reached a steady attrition rate of 19 mg h−1 and 21 mg h−1, respectively whereas Oterpklu limestone reached a steady rate of 17 mg h−1 after 4 h. The calcined limestones attrition rate was twice as high as their carbonated counterpart. The limestones attrited predominantly throgh fragmentation.

A molecular kinetic model incorporating catalyst acidity for hydrocarbon catalytic cracking

AbstractThis work built a molecular‐level kinetic model for hydrocarbon catalytic cracking, incorporating the catalyst acidity as the parameter to estimate reaction rates. The n‐decane and 1‐hexene co‐conversion catalytic cracking process was chosen as the studying case. The molecular reaction network was automatically generated using a computer‐aided algorithm. A modified linear free energy relationship was proposed to estimate the activation energy in a complex reaction system. The kinetic parameters were initially regressed from the experimental data under several reaction conditions. On this basis, the product composition was evaluated for three catalytic cracking catalysts with different Si/Al. The Bronsted acid and Lewis acid as the key catalyst properties were correlated with kinetic parameters. The built model can calculate the product distribution, gasoline composition, and molecular distribution at different reaction conditions for different catalysts. This sensitive study shows that it will facilitate the model‐based optimization of catalysts and reaction conditions according to product demands.

Recent advances in the development of nanosheet zeolites as heterogeneous catalysts

Recently, zeolites with two-dimensional structures, so-called nanosheet zeolites, have been intensively advanced owing to their excellent catalytic performance compared to conventional zeolite. This extremely thin nanosheet structure of zeolite provides more accessible active sites contributing to shortened diffusion pathways and primarily enables bulky molecules to undergo catalytic reactions. Several nanosheet zeolites, such as MFI, FAU, MOR, MWW, TS-1, have been successfully synthesized. Generally, they are obtained by direct synthesis method involving surfactant as structure-directing agent (SDA) and or seed. Interestingly, almost every part of the synthesis parameter conditions can alter the characteristics of this nanosheet zeolite. Thus, 2D zeolites also offer easily tunable characteristics. Up to now, nanosheet zeolites have been extensively studied as a catalyst in methanol conversion, catalytic cracking, isomerization, alkylation, oxidation/reduction, lignocellulose conversion, and other reactions. Furthermore, the modification of nanosheet zeolite could be pursued to enhance its catalytic performance. Pillaring is evidently effective in improving the textural properties of nanosheet zeolite by protecting the mesopore structure during the SDA removal. Herein, we comprehensively present the recent progress on the development of nanosheet zeolites. This review concludes with a summary of a discussion of remaining challenges and outlook for nanosheet catalyst technologies.

Synthesis of biofuel via catalytic fast pyrolysis of wood-plastic composite over low-cost catalysts

Thermogravimetric (TG) and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) analyses were performed to know the feasibility of low cost catalysts, γ-Al2O3, spent fluid catalytic cracking (FCC) catalyst, natural zeolite, to the pyrolysis of wood-plastic composite (WPC). Notably, the respective decomposition temperature of polyethylene and polypropylene in WPC was lowered with the use of low-cost catalysts during the catalytic fast pyrolysis (CFP). Furthermore, the lowest activation energy (Ea) of the CFP, obtained by the Ozawa method, was with the use of natural zeolite (127.5 kJ/mol), followed by the ones with the use of spent FCC catalyst (133.3 kJ/mol) and γ-Al2O3 (145.0 kJ/mol), respectively. In addition, the CFP over natural zeolite was less effective in terms of decreasing the production of low-quality hydrocarbons, paraffins and olefins having a wide carbon number distribution, and oxygenates compared to that over spent FCC catalyst and γ-Al2O3, respectively, due to the small pore size of natural zeolite. However, the largest amount of value-added aromatic hydrocarbons was produced in the CFP over natural zeolite among all the catalysts due to the high and strong acidity of natural zeolite.