Spent FCC Catalyst Research Articles

Single-step and stepwise pyrolysis to recover high-value chemicals from mixed polyolefins and polylactide

Biodegradable plastics are increasingly utilized due to environmental concerns but are typically disposed of together with conventional plastics. Valuable chemicals could be recovered from waste plastics by chemical recycling, but the mixing of different types of waste plastic affects the efficiency of the process. In this study, high-value chemicals were produced from a mixture of polyolefins and biodegradable polylactide by single and stepwise pyrolysis processes. The pyrolysis of polyolefins yielded fuel-like hydrocarbons, and the pyrolysis of polylactide yielded lactide and lactic acid. In the stepwise process, oxygenated compounds were only produced in the low-temperature step, and fuel-like hydrocarbons produced in the high-temperature step were not contaminated by oxygenated compounds. The influence of different catalysts on yields was investigated in the single-step and stepwise processes. The yield and selectivity of each product were significantly influenced by the type of catalyst and the composition of the plastic feedstock. Using a mixed feedstock of polyolefins and polylactide, low-temperature pyrolysis with a zeolite LTA catalyst favored the formation of lactide and lactic acid, while diesel-range hydrocarbons were obtained in the second step at a higher temperature. Aromatic and gasoline-range hydrocarbons were preferably produced from the single-step pyrolysis of polyolefins with spent FCC catalyst.

Fabrication of spent FCC catalyst TiO2-V2O5 composite material and its electrocatalytic performance

Fabrication of spent FCC catalyst TiO2-V2O5 composite material and its electrocatalytic performance

Recycling of Spent FCC Catalysts: Conversion of Leached Residues to Zeolite ZSM-5.

The commercial recycling of spent FCC catalyst typically focuses on recovering only 1-3 % of rare-earth elements, with the remaining residues often disposed of in landfills. Here, we present a novel method to close a recycling loop for spent FCC catalyst. The method involves a series of leaching steps: Firstly, the spent catalyst material is leached with HNO3 to remove rare-earth elements such as La; second, solvothermal leaching with HCl removes most of Al and impurities like Fe, Ni and V; finally, a third leaching with H2SO4 removes Ti. The solid residues are then used to synthesize ZSM-5 without the addition of any extra silicon or aluminum sources after mild activation. The impurities in the synthesis gel strongly modify the properties of the zeolite, with ZSM-5 crystals containing higher levels of impurities exhibiting lower crystallinities, surface areas, acidities, cracking activities, as well as larger particle sizes.

Enhancing light fuel production through catalytic pyrolysis of municipal mixed plastic waste over activated spent FCC catalyst

To address the issue of environmental pollution caused by waste plastics and increase their recycling utilization, a cost-effective chemical recycling method was employed in this study. It involved the use of spent fluid catalytic cracking (FCC) catalysts to convert waste plastics into valuable products. Sequential nitric acid treatment and pore expansion by ammonium hexafluorosilicate methods were employed to activate the spent FCC catalyst, with the aim of improving its physicochemical properties and enhancing the production of light fuel. The results demonstrated that activation treatment of the spent FCC catalyst improved the external surface area and meso-macroporous volumes of the activated catalysts. This process facilitated the initial cracking reaction of polyolefin macromolecules and alleviated the diffusion limitations of reactants and products within the pores of the catalyst, resulting in an increase in the yield of light fuels. Compared to the spent FCC catalyst, the activated catalysts exhibited 5.79–19.49% higher selectivities for light olefins and 21.67–29.76% higher yields for light fuels. These findings provide potential opportunities for the valuable utilization of waste plastics.

Study on the kinetics of catalytic pyrolysis of single and mixed waste plastics by spent FCC catalyst

Study on the kinetics of catalytic pyrolysis of single and mixed waste plastics by spent FCC catalyst

Acid attack on alkali-activated mortars: A test proposal

The durability of new binders in construction is one of the keys for further applications. The acid attack resistance of alkali-activated mortars (AAMs) was tested. A test proposal was developed, and the selected AAMs (precursors: blastfurnace slag, vitreous calcium silicoaluminate, fly ash and spent FCC catalyst) were analyzed in terms of acid neutralization capacity (ANC), mass loss at a constant pH= 2, and mass loss of the cubes immersed in 1 molar nitric acid solution. The results were compared to the mortars prepared with ordinary Portland cement. The ANC values were generally higher when the calcium content of the binder increased. The attacked mortars were characterized by thermogravimetry and microscopy techniques. The proposed test, based on three complementary experiments, allows the analysis of AAMs´ stability and the identification of more resistant systems to acid attack.

Biodiesel synthesis using spent FCC catalyst and CaO from a mixture of sunflower oil and oleic acid

A physical mixture of two heterogeneous catalysts, calcium oxide (CaO) and spent fluid catalytic cracking (SFCC) catalyst, was used to produce biodiesel from a mixture of refined sunflower oil (RSFO) and 5 wt% oleic acid. The reaction was performed with a 6: 1 M ratio of methanol to oil at 65 °C and 3 wt% catalyst loading. The SFCC catalyst loading was also varied to investigate its effect on soap formation and biodiesel production. The presence of the SFCC catalyst reduced the reaction time from 14 h to 7 h to achieve conversion >99 %. It also decreased the soap formation compared with the reaction catalyzed by CaO alone. The lowest oleic acid conversion to soap (~20%) was obtained for CaO + 20 % SFCC case. Calcium diglyceroxide (CaD) was also tested as a catalyst – it further reduced the reaction time to 1 h for 99 % conversion.

Performance, combustion, and emission characteristics of bio-oil produced by in situ catalytic pyrolysis of polypropylene using spent FCC.

Plastic waste is a rich source of hydrocarbons that can be converted into bio-oil through pyrolysis. In this study, bio-oil was produced by pyrolysis of waste-polypropylene using spent FCC catalyst. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that catalytically produced oil has the majority of compounds in the hydrocarbon range of C6-C18. The catalytic pyrolysis oil was blended with conventional fuel (diesel) to extensively investigate its suitability as a fuel substitute in a single-cylinder, four-stroke, 3.5kW, diesel internal combustion (IC) engine. Furthermore, four fuels, i.e., CF100PO00 (pure diesel), CF90PO10 (10% v/v pyrolysis oil blended with diesel), CF85PO15 (15% v/v pyrolysis oil blended with diesel), and CF80PO20 (20% v/v pyrolysis oil blended with diesel), were tested in IC diesel engine for performance, combustion, and exhaust emission analysis at 1500rpm. The tests were carried out at five loads, i.e., 1, 5, 10, 15, and 20 Nm. It was found that CF90PO10 produced 6.61% higher brake thermal efficiency (BTE), whereas CO2 exhaust emission decreased by 20% for CF80PO20 with respect to the pure diesel. Diesel blends with plastic pyrolysis oil can be a promising biofuel to improve engine performance and combustion characteristics without any significant engine modification.

Study on pyrolysis characteristics, kinetics and thermodynamics of waste tires catalytic pyrolysis with low-cost catalysts

As a non-biodegradable solid waste, waste tires (WTs) have adverse effects on the ecological environment and human health. Waste tires are a good source of energy. In order to reduce the energy consumption of waste tires pyrolysis, this paper explores the influence of three low-cost catalysts on the catalytic effect of waste tires. The results of thermogravimetric experiments show that the use of spent FCC catalyst (FCC), red mud (Rm) and fly ash (Fa) during pyrolysis is beneficial to reducing the initial pyrolysis temperature of WTs. The kinetic calculation results show that compared with the direct pyrolysis of WTs, the average activation energy of WTs catalyzed by red mud and fly ash is reduced by about 9.5 kJ/mol and 7.8 kJ/mol, respectively. The average pre-exponential factor (lnA) decreased by about 1.3 min−1 and 1.4 min−1, respectively. The thermodynamic calculation results show that the endothermic reaction occurs in both the pyrolysis and catalytic pyrolysis of WTs, and the pyrolysis process cannot be carried out spontaneously. The pyrolysis reaction process of waste tires can be characterized by the combination of kinetics and thermodynamics, which provides parameters for determining the relevant process conditions for the industrialization of catalytic pyrolysis of waste tires.

Possible use of spent FCC catalyst for upgrading of wax from the pyrolysis of plastics to liquid fuel

The cracking of heavy wax derived from mixed plastics (high-density polyethylene, low-density polyethylene, and polypropylene) to chemical and fuel purposes was explored using spent fluid catalytic cracking catalyst (spent FCC). The wax cracking was performed by a fixed-bed pyrolysis reactor with a slow heating rate. All catalysts, when compared to other catalysts (HY zeolite and MCM-41), could enhance liquid oil and gas production. While the spent FCC catalyst produced the highest liquid oil with least amount of coke production. The influence of spent FCC catalyst ratio on product distribution revealed that a catalyst-wax ratio of up to 1:1 resulted in a higher liquid oil yield than a low ratio. Additionally, the increase of cracking temperature promoted more oil production; however, at high temperature (above 400 °C) the evaporation of wax became more significant, and consequently a high portion of produced wax was obtained. Therefore, under suitable conditions, the spent FCC catalyst demonstrated the possibility of upgrading the heavy wax into liquid fuels and chemicals. In addition, this study also compared the products obtained from two processing routes using the spent FCC catalyst. The first route involved the pyrolysis of plastics into wax and then cracking the wax into liquid fuel, while the second route involved a one-step process that directly converted plastics into liquid fuel. The spent FCC catalyst promoted the production of diesel-range hydrocarbons and suppressed the aromatic production for the wax cracking. By contrast, the spent FCC catalyst significantly enhanced aromatic production during the cracking of mixed plastics.

Transforming industrial solid wastes into eco-friendly zeolite material for efficient heavy metal ion stabilization through host-guest combination

In this work, the “host-guest” combination has been conducted upon the utilization of dual industrial solid wastes, namely, spent FCC catalyst and red mud. The host of cancrinite zeolite was successfully synthesized under the optimum conditions of pre-treatment temperature of 500 °C for 4 h, spent FCC catalyst to NaOH of 0.8 (mass ratio), nitric acid to red mud of 5 (volume/mass), 140 °C for 12 h. The as-synthesized cancrinite sample had the maximum specific surface area of 251 m2/g, resulting in the relative leachability for Ni2+ (0.03%) and V2+ (0.38%) much better than that of spent FCC catalyst. The “host-guest” rule was discussed to reveal the mechanism for heavy metal ions stabilized into cancrinite zeolite. The feasibility (sources, synthesis methods, energy consumption and performance) of the present study was evaluated on a medium level by comparison with other literatures. Finally, the cost assessment of cancrinite zeolite was checked and the production cost was about 8 $/kg, decreasing the production price by at least 95% compared to commercial zeolites. Thus, the present study showed the feasibility and potential of solid wastes for stabilizing heavy metal ions, particularly in an advantage of the cost-effectiveness.

Feasibility Study of Plastic Waste Pyrolysis from Municipal Solid Waste Landfill with Spent FCC Catalyst

Globally, there is growing concern about the problem of plastic waste. The majority of plastic waste is dumped into landfills, where it occupies space, reducing landfill capacity and causing a variety of environmental issues. Plastic waste pyrolysis has gained popularity because it can reduce the volume of plastic waste while also producing alternative fuels. This study assessed the feasibility of producing fuel oil from plastic waste using the catalytic pyrolysis process. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) waste samples were collected from municipal solid waste (MSW) landfills on Samui Island, Surat Thani Province, Thailand. Pyrolysis was carried out in a 3-L bench-scale reactor at 450ºC using a 3% spent FCC catalyst. PE, PP, PS, and mixed plastic waste were used as feedstocks. The results showed that the pyrolysis of PS produced the most liquid product (91.44 wt%), whereas the pyrolysis of PE produced the highest percentage of diesel range product (36.60 wt%). Furthermore, the results of the analysis revealed that the characteristics of diesel from improved PE pyrolysis oil by naphtha removal were similar to those of commercial diesel B7. According to the cost-benefit analysis, the operating costs of pyrolysis oil and improved diesel were 0.37 and 0.65 USD/L, respectively, which were lower than the current market price of diesel B7. The findings of the study demonstrated the feasibility of converting plastic waste from MSW on Samui Island into alternative energy using eco-friendly and cost-effective technology.

Study of simultaneous adsorption of ammonium and phosphate in waters by La-F4A zeolites prepared from spent FCC catalyst

The problem of resource disposal of massive spent fluid catalytic catalyst needs to be solved urgently. Thus an environmentally friendly, highly efficient and economical cost adsorbent used for nitrogen and phosphorus removal was prepared from spent fluid catalytic catalyst. A novel 4A zeolite adsorbent loaded with lanthanum hydroxide (La-F4A) was prepared by acid leaching pretreatment, alkali fusion roasting hydrothermal and co-precipitation method. And use La-F4A in the study of simultaneous adsorption of ammonia-nitrogen and phosphorus in water. Adsorption experiments were carried out under the condition that the primordial concentrations of PO4 and NH4+-N were respectively 1 & 10mg/L. La-F4A has an adaptive adsorption ability on NH4+-N and PO4 in the pH range of 4-9. When the temperature is 298K, the dosage is 1.0 g/L, the contact time is 240 min, and test water pH=7, the maximum adsorption capacities for NH4+-N and PO4 are 7.64 mg/g and 0.93 mg/g respectively. The behaviours accord with the pseudo-second-order adsorption kinetic model. The adsorption of PO4 conforms to the Langmuir isotherm model while NH4+-N conforms to the Freundlich isotherm model. Coexisting anions have almost no effect on the adsorption of PO4, coexisting cations have different inhibitory effects on the adsorption of NH4+-N. After four desorption cycles, the removal efficiency of La-F4A for NH4+-N and PO4 was 77% and 93% of the initial capacity. There are both chemical adsorption and physical adsorption in the process. The ammonium removal mechanism is the ion exchange between NH4+ and Na+ in the framework, and the phosphate removal mechanism is the ligand exchange between PO4 and hydroxyl to form LaPO4. La-F4A is regarded to be an excellent adsorbent for ammonium and phosphate removal.

Pyrolytic Depolymerization Mechanisms for Post-Consumer Plastic Wastes

Fast pyrolysis of five post-consumer plastic waste materials was studied using pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) technique. Prescription medicine bottles, landfill liners, and one type of industrial plastic waste represented polyolefin-based polymers, whereas packaging material represented polystyrene, and other industrial plastic waste represented polyurethane. The noncatalytic and catalytic degradation mechanisms of all five post-consumer plastic wastes were elucidated. The noncatalytic pyrolysis experiments were conducted at a temperature of 600 °C for a residence time of 5 min. For catalytic pyrolysis, a spent FCC catalyst was utilized for polystyrene, a sulfated zirconia-based catalyst was utilized for polyurethane, and a Y-zeolite catalyst was used for polyolefinic plastic waste. The results suggested that the thermal reaction has higher monomeric and oligomeric selectivity than the catalytic reaction. Results from the catalytic runs showed that the addition of catalysts greatly influences product compositions and has a significant effect on the selectivity of a specific compound. One of the plastic wastes, landfill liner, was selected for a batch scale pyrolysis at 420–440 °C using Y-zeolite as a catalyst to demonstrate the product properties and potential use of the liquid product formed. The complete product distribution of plastic crude oil was performed followed by distillation to produce aviation range fuel. The fuel properties of aviation range fuel were examined, and results suggested that the fuel fraction can be easily blended with commercially available fuels for direct applications.

Study on the pyrolysis characteristics of sawdust catalyzed by spent FCC catalyst and blast furnace ash

Two industrial wastes, spent FCC catalyst (sFCCc) and blast furnace ash (BFA), were used as catalysts in the fast pyrolysis of sawdust, and the catalytic pyrolysis reaction characteristics of sawdust in the temperature range of 400–700 °C were explored. The results showed that both catalysts promoted the conversion from liquid products to gaseous products, and the highest gas yield was 52.60% at 700 °C catalyzed by BFA. The sFCCc had stronger deoxygenation activity at 500–600 °C, resulting in higher CO and CO2 production in gaseous products. While BFA had higher polycondensation and dehydrogenation activity at 600–700 °C, and promoted the formation of polycyclic aromatic compounds and H2. Pyrolysis oil was mainly composed of phenols. The sFCCc promoted the conversion of methoxy phenol to benzenediol. FT-IR analysis of pyrolysis oil showed that sFCCc promoted the removal of C–O and C=O, resulting in decreased acid and ester compounds and increased CO2 yield.

In Situ and Ex Situ Catalytic Co-pyrolysis of Lignocellulosic Biomass and Plastics (Low-Density and High-Density Polyethylene) Using Spent FCC Catalyst

In Situ and Ex Situ Catalytic Co-pyrolysis of Lignocellulosic Biomass and Plastics (Low-Density and High-Density Polyethylene) Using Spent FCC Catalyst

Lanthanum recycling from spent FCC catalyst through leaching assisted by electrokinetic remediation: Influence of the process conditions on mass transfer

The electrokinetic remediation assistance on the leaching of spent FCC catalysts demonstrated satisfactory performance as an alternative method to the traditional leaching method, aiming to recycle rare earth elements from this solid waste, by former studies. The present work identified the process conditions that improved the mass transfer performance of lanthanum by electrokinetic phenomena, by means of a central composite design and variance analysis. Thereby, the system that operated with the sulfuric acid concentration in the electrolyte of 1 mol/l and the applied electric field of 0.15 V/m, for 8 h of the experiment, was the best in terms of energy and acid consumption per mass of lanthanum recovered, amid the tested conditions.

Characteristics of Pore Structure Evolution of Spent Fcc Catalyst and its Effect Mechanism on Regeneration at Different Atmospheres

Characteristics of Pore Structure Evolution of Spent Fcc Catalyst and its Effect Mechanism on Regeneration at Different Atmospheres

Clean Energy from Plastic: Production of Pyrolysis Oil from Plastic Waste

Plastic materials’ applications are expanding on a daily basis due to their unique properties, which enable them to replace other materials in their appli- cations while still meeting customer needs thanks to advanced technology. In Sultanate of Oman 20.9% of the solid waste are plastics. As a result, more plas- tic produced, which leads to an increase in plastic waste. Since it is produced from an unsustainable crude oil source using a high-energy consuming method, plastic waste contributes significantly to soil, water, and even air pollution. As a result, they are non- biodegradable, resulting in high greenhouse gas emis- sions, a plastic waste crisis, and the non-renewable fossil fuel petroleum being depleted. One of the methods for handling plastic waste that has been devel- oped is the energy recovery process. Given that petroleum was the primary source of plastic, converting it to liquid oil via pyrolysis had enormous poten- tial, as the resulting oil had a calorific value comparable to commercial fuel. Pyrolysis of plastics is a chemical reaction in which larger molecules are bro- ken down into smaller molecules using heat. As a result, the aim of this study is to catalytically pyrolyze most commonly plastic waste (PET, HDPE) into a liquid oil using a spent FCC catalyst. This will contribute to the plastic waste management program while also providing a renewable energy source which can be used in boilers combustion and engines fueling, reducing plastic waste. Pyrolysis has been found to be an excellent solution for transforming Petro- plastics into different functional products, with liquid oil production reaching up to 80%, according to previous studies. This study conduct Pyrolysis of PET and HDPE plastic waste the poly fuel produced was analyzed by Gas Chro- matography (GC) instrument and compared with commercial diesel properties.

Enhanced regeneration of spent FCC catalyst by using oxalic acid-sulfuric acid mixture under ultrasonic irradiation

An effective method comprising the immersion in dilute sulfuric acid and the leaching in a mixture of sulfuric acid and oxalic acid under ultrasonic irradiation is provided to improve the removal effect of harmful metals in spent FCC catalyst without destroying the zeolite Y framework and the microstructure of spent catalyst particle. The influence of different experimental conditions on the regeneration effect of spent catalyst is studied by using SEM, EPMA-EDX, XRD, ICP, N2 adsorption, and particle size analysis techniques. The experimental results show that immersion in sulfuric acid can effectively restore blocked pores and increase the specific surface area of spent catalyst by 51.7% compared with the untreated spent catalyst, which is beneficial to the subsequent acid leaching. After leaching in a mixture of 0.5 mol/L oxalic acid and 2 wt.% sulfuric acid for 30 min at 70 °C with an ultrasonic power of 250 W, the regenerated catalyst with complete particle structure and zeolite Y framework is obtained with the removing rates of Fe, V, and Ni being 36.2, 43.8 and 30.1%, respectively, whereas Al loss is only 7.9%. Compared with conventional leaching, ultrasonic assisted leaching only needs 1/4 of the time to achieve much the same harmful metal removal effect and has superior advantages in retaining the integrity of particles.