Equilibrium FCC Catalyst Research Articles

Conversion of rapeseed oil via catalytic cracking: Effect of the ZSM-5 catalyst on the deoxygenation process

In the present paper rapeseed oil was considered as a potential biomass-based source of motor fuels and petrochemicals. The conversion of pure rapeseed oil and its mixture with hydrogenated vacuum gas oil (HVGO) under simulated fluid catalytic cracking conditions via MAT-test was investigated. Besides inorganic gases (CO, CO2) and water there were also organic oxygenated compounds (alkylphenolics, carboxylic acids etc.) found in the organic phase of the liquid product. For their removal we proposed to improve the catalytic system consisting predominantly of pure standard FCC equilibrium catalyst by the ZSM-5-based FCC catalyst additive. The extent of liquid product deoxygenation and the yield of gasoline were the main monitored parameters. The use of the catalyst mixture containing 10wt.% of ZSM-5 catalyst additive and 90wt.% of the standard FCC-catalyst in the case of pure rapeseed oil resulted in a practically complete removal of the organic oxygenates from the liquid product. In the case of the feed mixture rapeseed oi–-vacuum gas oil (1:9) there was found virtually no organic oxygenates in the liquid product with the gasoline yield close to the one of the pure HVGO cracking.

Catalytic pyrolysis of palm kernel shell waste in a fluidized bed

The catalytic pyrolysis of palm kernel shell was investigated in a fluidized bed with zsm-5 and equilibrium FCC (Ecat) catalysts. Catalytic pyrolysis oil yields were remarkably reduced and gas yields were increased due to the higher catalytic reaction of primary volatiles compared to non-catalytic pyrolysis. Char yields were affected by temperature and the pore structure of the catalysts. The pyrolysis oil was characterized by lower H/C and O/C molar ratios due to aromatization and deoxygenation of volatiles by the catalysts. The catalytic pyrolysis oils contained more oxygen and nitrogen and less sulfur than petroleum oils. The oils had a high concentration of nitriles, with a carbon number distribution similar to fatty acids. The catalytic pyrolysis oils featured high nitriles yield with Ecat and high aromatics yield in the light fraction with zsm-5, due to characteristics of the catalyst. The catalytic pyrolysis oils showed potentials as feedstocks for bio-diesel and chemicals.

Catalytic cracking of pyrolysis oil oxygenates (aliphatic and aromatic) with vacuum gas oil and their characterization

In the present work an attempt has been made to study the effect of catalyst-to-oil ratio (C/O) on the product distribution for the catalytic cracking of mixture of vacuum gas oil (VGO) with guaiacol and acetic acid, which are the representative model compounds of the biomass-derived fast pyrolysis oil. The catalytic cracking of mixture of VGO has been carried out using industrially available FCC equilibrium catalyst (E-CAT) in an advanced cracking evaluation ACE-R FCC unit. The FCC feed, distillates and liquid products are analyzed using Fourier transform infrared spectroscopy, and structurally characterized by 1H, gated decoupled 13C NMR methods. The average structural parameters like branchiness index, substitution index, average length of alkyl chains, and fraction of aromaticity per molecule are obtained from NMR data. The SIM distillation based product analysis indicated that the presence of guaiacol increased the product selectivity of gasoline fraction; whereas the presence of acetic acid clearly increased the yield of light olefins, CO and CO2. The 1H and 13C NMR data indicated that the fraction of aromaticity for both Feed B (vacuum gas oil+acetic acid) and Feed C (vacuum gas oil+guaiacol) increased, after catalytic cracking, with increase in C/O ratio from 3 to 9. The equilibrium FCC catalyst is able to crack oxygenates presents in pyrolysis oil such as acetic acid and guaiacol. Further the crackability pattern of pyrolysis oxygenates supported by the vibrations of CO and OH absorption peaks (of FTIR) and NMR data of liquid product.

Products and coke from the conversion of bio-oil acids, esters, aldehydes and ketones over equilibrium FCC catalysts

Reactivity and product distributions in the conversion of five different compounds representing typical species in bio-oils were studied over an equilibrium FCC catalyst at 500 °C during 60 s in a fixed bed reactor. Acetic acid, methyl acetate, furfural, 3-methyl-2-pentanone and 2-hidroxy-3-methylcyclopentenone were dissolved at 5% wt. in water. Thermal conversions were performed under the same conditions with inert SiC in the bed. The test compounds converted very differently, deoxygenation being produced by decarboxylation and dehydration. Furfural and 3-methyl-2-pentanone gave the highest yields of hydrocarbons, with high selectivity to light olefins and, when liquid (case of ketones), to aromatics. Methyl acetate gave the highest yield of oxygenated compounds. Coke yields were important (maximum 12.8% wt., 2-hidroxy-3-methylcyclopentenone). Thermal conversions were similar to the catalytic ones with acetic acid and methyl acetate, and much lower for the other reactants. Compared catalytic experiments, the thermal yields of hydrocarbons were much higher with acetic acid, and the yields of oxygenated higher with methyl acetate ester. Much less hydrocarbons were produced thermally with the other reactants. This information may be useful for predicting contributions if these compounds are to be co-processed in existing FCC units or upgraded over acidic catalysts.

Upgrading of bio-oils over equilibrium FCC catalysts. Contribution from alcohols, phenols and aromatic ethers

The conversions of oxygenated compounds of bio-oils (alcohols, phenols and aromatic ethers) on a equilibrium FCC catalyst were studied at 500°C during 60s in a fixed bed laboratory reactor. Methanol, phenol and 2,6-dimethoxyphenol were dissolved in water and 1,2,4-trimethoxybenzene in benzene at 5%wt. Identical experiments were performed over inert SiC. Conversions were very different, the highest one being that of 1,2,4-trimethoxybenzene (95.7%wt.), followed by 2,6-dimethoxyphenol (75.0%wt.), methanol (60.8%wt.) and phenol (54.9%wt.). Deoxygenation in all the reactants was from dehydration and decarboxylation. The highest yield of hydrocarbons (47.1%wt.) and coke (16.0%wt.) were from 1,2,4-trimethoxybenzene, which, together with methanol, yielded mainly aromatics in the gasoline range. On the contrary, phenol and syringol yielded C4-hydrocarbons with high content of olefins. The highest amounts of oxygenated compounds were produced by 2,6-dimethoxyphenol. The thermal conversions were similar to the catalytic ones in the only case of 1,2,4-trimethoxybenzene, but much lower with the other reactants. In comparison to the catalytic experiments, thermal tests yielded much more hydrocarbons with 1,2,4-trimethoxybenzene, and oxygenated compounds with 2,6-dimethoxyphenol, than the other reactants. These tests could help in the prediction of specific contributions by these reactants if bio-oils are co-processed in FCC units or upgraded over acidic catalysts.

Application of ferrierite zeolite in high-olefin catalytic cracking

The potential use of pure ferrierite (H-FER) or H-FER/H-ZSM-5 blends in catalytic cracking to enhance the production of light olefins was evaluated in the catalytic cracking of n-hexane at 500°C and the high-olefin catalytic cracking (HOCC) of a Brazilian gasoil feedstock at 600°C. For the n-hexane cracking evaluation, only pure zeolites were employed. For the HOCC testing, both pure zeolites and the H-FER/H-ZSM-5 blends were mixed with a reference commercial FCC equilibrium catalyst to give a total zeolite content ranging from 0.5 to 8wt.%. In both catalytic tests, the use of ferrierite resulted in the improvement of olefin production. The H-FER zeolite exhibited higher propylene and butene selectivities than H-ZSM-5. Conversely, H-ZSM-5 resulted in higher ethylene selectivity. In the HOCC tests, pure H-ZSM-5 exhibited higher ethylene and propylene yields than H-FER. However, the use of the H-ZSM-5/H-FER blends caused higher yields of the total amount of light olefins (ethylene, propylene and C4 olefins) than when only pure H-ZSM-5 zeolite was employed. This synergetic effect of the combination of the H-FER and H-ZSM-5 zeolites is reported for the first time in the literature and can be explained by taking into account the fact that the H-FER zeolite has a lower hydrogen transfer ability.

Conversion of pine sawdust bio-oil (raw and thermally processed) over equilibrium FCC catalysts

A raw bio-oil from pine sawdust, the liquid product from its thermal conditioning and a synthetic bio-oil composed by eight model compounds representing the main chemical groups in bio-oils, were converted thermally and over a commercial equilibrium FCC catalyst. The experiments were performed in a fixed bed reactor at 500°C. The highest hydrocarbon yield (53.5wt.%) was obtained with the conditioned liquid. The coke yields were significant in all the cases, from 9 to 14wt.%. The synthetic bio-oil produced lesser hydrocarbons and more oxygenated compounds and coke than the authentic feedstocks from biomass. The previous thermal treatment of the raw bio-oil had the positive effects of increasing 25% the yield of hydrocarbons, decreasing 55% the yield of oxygenated compounds and decreasing 20% the yield of coke, particularly the more condensed coke.

Fundamentals of Petroleum Residue Cracking Gasification for Coproduction of Oil and Syngas

Vacuum residue (VR) was stepwise converted via catalytic cracking for liquid and coke gasification for hydrogen-rich syngas in a fluidized bed reactor. Silica sand and spent equilibrium FCC (E-FCC) catalyst were used as the catalysts for VR cracking. The liquid yield was about 89 wt % at 568 °C using silica sand as catalyst and the conversion ratio of heavy fractions was only 55%. About 60 wt % VR was converted into gas and coke over the E-FCC catalyst at 480 °C, showing that the catalyst had too strong acidity for VR cracking. The E-FCC catalyst was thus modified (aged) with both hydrothermal treatment and impregnation of alkali and alkaline-earth metals (K and Mg) to weaken its acidity and facilitate the liquid oil production. The aged FCC (A-FCC) catalyst exhibited appropriate cracking activity to allow both the expected liquid yield of about 80 wt % and heavy fraction conversion ratio of up to 98 wt %. Steam gasification of the deposited coke on the surface of the A-FCC catalyst resulted in the produc...

Evaluation of pyrolysis product of virgin high density polyethylene degradation using different process parameters in a stirred reactor

The yield as well as molecular weight and composition of the condensed product generated from the HDPE was studied to gain insight into the role of temperature, equilibrium FCC catalyst, agitator speed and carrier gas on the pyrolysis products. Pyrolysis was done in a suite stirred bucchi stainless-steel autoclave reactor. The effect of process parameters such as degradation temperature, catalyst/polymer ratio (%), carrier gas type and stirrer rate on the condensed product yield and composition was determined. Reaction products were determined by GC analysis and shown to contain naphthenes (cycloalkanes), paraffins (alkanes), olefins (alkenes) and aromatics.The maximum “fuel like” condensed product yields were at 450°C and 10% catalyst, respectively.The influence of different types of carrier gasses with varied molecular weights and reactivity was studied. Hydrogen as a reactive carrier gas increased the condensed and paraffinic product yield. Appropriate heat transfer – by stirring – can increase the catalyst efficiency in a stirred reactor. It is demonstrated that the use of equilibrium FCC commercial catalyst under appropriate reaction conditions can have the ability to control both the condensed yield and carbon number distribution from HDPE degradation, and thus potentially decrease the process cost with more valuable hydrocarbons.

Recycling of waste plastics into fuels. LDPE conversion in FCC

In order to study the tertiary recycling of waste polymers in standard FCC units low density polyethylene (LDPE) was dissolved into a commercial vacuum gas oil at 2 and 6wt.% and converted over two equilibrium FCC catalysts of the octane-barrel and resid types in a CREC Riser Simulator laboratory reactor. The reaction temperatures were 500, 525 and 550°C, the mass catalyst to oil relationship was 6.35 and the contact times were from 3 to 30s. The study included the effect of the concentration of LDPE over conversion, the various product (dry gas, LPG, gasoline, LCO and coke) yields and selectivities. Results were very similar for the two concentrations. At typical conversions of 70wt.%, dry gas and gasoline yields increased about 10wt.%, LPG yields between 9 and 13wt.%, LCO yields decreased more than 15wt.% and coke yields were lower than 7.7wt.% The RON index of gasoline was improved slightly (up to one point), mainly due to significant increases in olefin concentrations, while the fuel quality of the LCO cut was not affected. LDPE is easily converted and seems to be subjected to primary reactions of catalytic cracking, thus increasing the yields of olefins in the LPG and gasoline boiling ranges. It was concluded that recycling waste LDPE by co-processing it as part of conventional feeds to the FCC would not interfere with the standard operation.

In-situ upgrading of biomass pyrolysis vapors: Catalyst screening on a fixed bed reactor

In-situ catalytic upgrading of biomass fast pyrolysis vapors was performed in a fixed bed bench-scale reactor at 500°C, for catalyst screening purposes. The catalytic materials tested include a commercial equilibrium FCC catalyst (E-cat), various commercial ZSM-5 formulations, magnesium oxide and alumina materials with varying specific surface areas, nickel monoxide, zirconia/titania, tetragonal zirconia, titania and silica alumina. The bio-oil was characterized measuring its water content, the carbon–hydrogen–oxygen (by difference) content and the chemical composition of its organic fraction. Each catalytic material displayed different catalytic effects. High surface area alumina catalysts displayed the highest selectivity towards hydrocarbons, yielding however low organic liquid products. Zirconia/titania exhibited good selectivity towards desired compounds, yielding higher organic liquid product than the alumina catalysts. The ZSM-5 formulation with the highest surface area displayed the most balanced performance having a moderate selectivity towards hydrocarbons, reducing undesirable compounds and producing organic liquid products at acceptable yields.

A Primary Study on Preparation of Mullite with Solid Waste

A novel technique of Spent FCC equilibrium catalyst utilization is presented and mullite are prepared from it. The chemical composition, structure and thermal stability of the spent FCC equilibrium catalyst from oil refinery are characterized by XRD, FT-IR, DTA-TG, Fully chemical analysis technique, SEM. Mullite specimens are prepared by reaction sintering the spent FCC equilibrium catalyst at different temperatures. The result indicates that at 1300-1350°C, the spent FCC equilibrium catalyst could be used to prepare high purity mullite.

Comparison between MAT Flow Fixed Bed and Batch Fluidized Bed Reactors in the Evaluation of FCC Catalysts. 2. Naphtha Composition

A comparison was performed between the performances of a MAT type reactor (flow fixed bed) and a CREC riser simulator reactor (batch fluidized bed) in the conversion of two VGO feedstocks (aromatic and paraffinic types) over three commercial equilibrium FCC catalysts, under similar conditions. In both units the reaction temperatures were 500 and 550 °C. The catalyst-to-oil relationships were from 2.3 to 6.2 (cumulative) and 6.2, and the times were from 15 to 40 s (time on stream) and from 5 to 30 s (reaction time) in the MAT reactor and the CREC riser simulator reactor, respectively. Results were compared in terms of the composition of the naphtha, in view of its contribution to the gasoline pool. Advantages were observed with data from the CREC riser simulator reactor, mainly derived from the fact that naphtha yields were, in general, closer to commercial values and showed a stable primary product behavior. Thus, they are easier to analyze as naphtha selectivities did not depend on the conversion reached. On the contrary, naphtha yields in the MAT reactor showed a maximum as a function of conversion. The comparison of the product distributions observed in the naphthas from each unit at the same conversion level showed that they can be very different; the naphtha obtained in the CREC riser simulator reactor was more paraffinic and less aromatic than the one obtained with the MAT reactor, and the proportions were similar to commercial values. Ranks of catalysts based on the various hydrocarbon fractions observed in the naphtha from each setup also differed in most of the cases. The differences in the results could be the consequence of notoriously different contact between reactants and catalyst and operative modes in each reactor, then impacting on the complex set of reactions occurring in FCC.

Comparison between MAT Flow Fixed Bed and Batch Fluidized Bed Reactors in the Evaluation of FCC Catalysts. 1. Conversion and Yields of the Main Hydrocarbon Groups

A comparison was performed between the performances of a MAT-type reactor (flow fixed bed) and a CREC Riser Simulator reactor (batch fluidized bed) in the conversion of two VGO feedstocks (aromatic and paraffinic types) over three commercial equilibrium FCC catalysts under similar conditions. In both units the reaction temperatures were 500 and 550 °C. The catalyst to oil relationships were from 2.3 to 6.2 (cumulative) and 6.2, and the times were from 15 to 40 s (time on stream) and from 5 to 30 s (reaction time) in the MAT reactor and the CREC Riser Simulator reactor, respectively. A comparison of the product yield structure in each unit at the same conversion showed that they were very different due to the significant differences in the contact between reactants and catalyst and operative modes. Results were compared in terms of VGO conversion and the yields of the most important hydrocarbon groups LPG, gasoline, and coke. Some advantages were observed with data from the CREC Riser Simulator reactor, derived from the fact that yields are in general closer to commercial values, mainly concerning gasoline and coke. The yields of the main hydrocarbon groups also followed linear behaviors in this reactor, thus being easier to analyze, as selectivities did not depend on the conversion reached. On the contrary, yields showed a strong dependency on conversion in the MAT reactor, particularly in the case of gasoline and coke. The high coke yield in the first moments of the experiments in the MAT reactor could lead to modifications in the selectivities to certain reactions and products.

Tertiary recycling of commingled polymer waste over commercial FCC equilibrium catalysts for producing hydrocarbons

A mixture of post-consumer polymer waste (PE/PP/PS) was pyrolysed over cracking catalysts using a fluidising reaction system similar to the FCC process operating isothermally at ambient pressure. Greater product selectivity was observed with a commercial FCC equilibrium catalyst (FCC-E1) with about 53 wt% olefin products in the C 3–C 6 range. Experiments carried out with various catalysts gave good yields of valuable hydrocarbons with differing selectivity in the final products dependent on reaction conditions. A kinetic model based on a lumping reaction scheme for the observed products and catalyst coking behaviours has been investigated. The model gave a good representation of experiment results. This model provides the benefits of lumping product selectivity, in each reaction step, in relation to the performance of the catalyst used and particle size selected as well as the effect of operation conditions, such as rate of fluidising gas and reaction temperature. It is demonstrated that under appropriate reaction temperatures and suitable catalysts can have the ability to control both the product yield and product distribution from polymer degradation, and can potentially lead to a cheaper process with more valuable products.

Study of cracking FCC naphtha in a secondary riser of the FCC unit for maximum propylene production

To satisfy the increasing propylene demand, reprocessing FCC naphtha in a secondary riser of the FCC unit was investigated. To this aim, a full range FCC naphtha was cracked over a mixture of two kinds of commercial equilibrium FCC catalysts, which contained 95 t.% Y zeolite-based catalyst and 5 wt.% ZSM-5 zeolite-based additive. The effects of operating parameters such as reaction temperature (temperature of the riser outlet), catalyst-to-oil ratio and residence time on FCC naphtha cracking were studied in a continuous pilot plant. This work demonstrates that FCC naphtha requires high operating severities to crack, and approximately 12–19 wt.% FCC naphtha can be transformed into propylene. The conversion and yield of propylene showed a rapid increase with increasing reaction temperature, and the increase of catalyst-to-oil ratio also enhanced FCC naphtha cracking, even at high reaction temperature. However, at high catalyst-to-oil reactions, hydrogen-transfer reactions constrain further increases in light olefin yields. At these high operating severities, shortening residence time is an appropriate way to obtain high yields of propylene combined with (i) lower yields of dry gas and (ii) a lower apparent hydrogen-transfer coefficient.

Degradation of LDPE/VGO mixtures to fuels using a FCC equilibrium catalyst in a sand fluidized bed reactor

Abstract Plastic degradation for recovery of useful products or raw materials is a very interesting alternative for reducing the plastic accumulation. This paper explores the possibility of using refinery facilities to carry out the plastic cracking as well as to take the most of the products obtained. In the present work, LDPE/VGO blends with different percentages of polymer are degraded in presence of a FCC equilibrium catalyst. The reactor used in this study is a laboratory scale sand fluidized bed reactor at 500 °C, and a 7:1 catalyst:LDPE/VGO blend ratio in order to simulate the operating conditions in a large scale industrial reactor. Polyethylene blends evaluated show relative proportions of LDPE of 0, 6, 25, 75 and 100% (w/w). Gas and liquid compounds were collected and quantified. The results obtained are compared with those generated in a thermal cracking. In all cases, the FCC equilibrium catalyst showed a high selectivity to the production of isobutane and isopentane in the volatile compounds as well as to aromatics in the liquid products. Results shown in this paper evidences the viability of introducing plastics into FCC unit, producing potential valuable products from low value materials.

Passivation of vanadium in an equilibrium FCC catalyst at short contact-times

An equilibrium FCC (ECAT) sample containing 2800 ppm vanadium and 2500 ppm nickel was characterized by ESR and ESCA, and tested in a microactivity test (MAT) to study the effect of reductive pretreatments at elevated temperatures. From ESR and ESCA studies, it is found that the vanadium of the ECAT sample consists of V 4+ converting to a considerable part of V 3+ after a treatment with 5% H 2 in N 2 between 650 and 750 °C. Approximately, 40% of the vanadium exists as V 3+ after such a treatment at 700–750 °C. The reductive procedure led to an increase in the gasoline yield and a reduction in the coke yield in MAT when processing an atmospheric residue from the North Sea at 524 °C. It is shown that it is sufficient with a reduction/passivation time as short as 3 min in hydrogen at 689 °C to obtain a significant effect on the gasoline and coke yields. The results indicate that the main part of the observed reduction occurs in the outer layer of the particle at such short reduction times.

Thermal degradation of polyethylene and polystyrene from the packaging industry over different catalysts into fuel-like feed stocks

Thermal degradation of waste polymers was carried out as a suitable technique for converting plastic polymers into liquid hydrocarbons, which could be used as feed stock materials. The catalytic degradation of waste plastics (polyethylene and polystyrene) was investigated in a batch reactor over different catalysts (FCC, ZSM-5 and clinoptillolite). The effects of catalysts and their average grain size on the properties of main degradation products (gases, gasoline, diesel oil) are discussed. The temperature range of 410–450 °C was used in the process. Both equilibrium FCC catalyst and natural clinoptilolite zeolite catalyst had good catalytic activity to produce light hydrocarbon liquids, and ZSM-5 catalyst produced the highest amount of gaseous products. Gases and liquids formed in cracking reactions were analyzed by gas chromatography. The liquid products consisted of a wide spectrum of hydrocarbons distributed within the C 5–C 28 carbon number range depending on the cracking parameters. The composition of hydrocarbons had linear non-branched structure in case of polyethylene, while from polystyrene more aromatics (ethyl-benzene, styrene, toluene, and benzene) were produced. The yields of volatile products increased with increasing degradation temperature. The olefin content of liquids was measured with an infrared technique and an olefin concentration of 50–60% was observed. The concentration of unsaturated compounds increased with decreasing temperature, and in the presence of catalysts. The activation energies were calculated on the basis of the composition of volatile products. The apparent activation energies were decreased by catalysts and catalyst caused both carbon-chain and double bond isomerisation.

Kinetic Model of the Chemical Recycling of Waste Polyethylene into Fuels

Tertiary recycling methods offer potential possibilities for the utilization of waste plastics. Thermal and catalytic degradation of low-density polyethylene wastes were studied in a batch reactor under mild cracking conditions to derive liquid cracking products of olefins and paraffins. Zeolite catalysts with different activities were studied: a commercial equilibrium FCC catalyst, an H form ZSM-5 catalyst, and a natural clinoptilolite containing rhyolite tuff. The catalytic processes could convert waste polymers into valuable hydrocarbons. The properties of products could be modified by the use of catalysts. The olefin content and the position of the olefinic double bonds were investigated with IR spectrometry. In the presence of catalysts the olefin content increased, and the terminal bonds migrated into internal positions. Furthermore the liquid products had lower average molecular weights than those obtained without catalysts. The activation energies of the cracking reactions with or without catalysts were determined. The apparent activation energy was lower in catalytic than that in thermal degradation. The cracking reaction rates were modelled and the reaction rate constant of each hydrocarbon type was calculated. The model gives a good approximation of the experimental results obtained from the degradation of LDPE waste in the presence and absence of catalysts. Under the studied parameters, liquids were formed with suitable properties for further uses (e.g. low sulphur content, low pour point).