Naphtha Yield Research Articles

Hydrocracking of a HDPE/VGO Blend: Influence of Catalyst-to-Feed Ratio on Fuel Yield and Composition

The effects that the catalyst-to-feed ratio have on the yields of products and composition of the naphtha and light cycle oil (LCO) fractions in the hydrocracking of a blend composed of high-density polyethylene (HDPE) and vacuum gasoil (VGO) using a PtPd/HY catalyst were assessed. The hydrocracking runs were carried out in a batch reactor fixing the following operation conditions: 420 °C, 80 bar, 120 min and an HDPE-to-VGO ratio of 0.2 gHDPE gVGO−1, varying the catalyst-to-feed mass ratio within the 0.05–0.1 gcatalyst gfeed−1 range. The obtained results exposed that a catalyst-to-feed mass ratio of 0.075 gcatalyst gfeed−1 provided the best results, since the conversion of the heavy cycle oil (HCO) fraction and of the HDPE offered quite high values (73.1 and 63.9%, respectively) without causing an excessive overcracking in the form of gas products (the yield of gases was of 25%). Moreover, an interesting yield of naphtha (37.0 wt%) with an RON within the commercial standards (92.5) was obtained. With regard to coke formation, not-so-developed structures were formed for a catalyst-to-feed mass ratio of 0.075 gcatalyst gfeed−1, easing their combustion and presumably extending the lifespan of the catalyst.

Unlocking naphtha from polyolefins using Ni-based hydrocracking catalysts

Naphtha (C5-C12 alkanes) is a platform feedstock in the petroleum industry and an ideal target for reutilizing plastic waste at scale. Hydrocracking has emerged as a promising technology for deconstructing polyolefins to naphtha. However, contemporary catalysts rely on Pt to achieve high rates, while earth-abundant metals (EAM) perform poorly. Herein, we develop high-performance Ni/BEA catalysts for polyolefin hydrocracking, achieving complete low-density polyethylene (LDPE) deconstruction with 80 % maximum naphtha yield within 12 h at 250 °C, 60 bar H2, and a catalyst-to-polymer ratio of 1:100. These catalysts are versatile, accommodating virgin resins and commercial polymer products, and are directly reusable and regenerable. Comparative analysis highlights that 5Ni/BEA(25) exhibits the highest naphtha productivity of 11.4 gNaphthagcat∙h, surpassing previously reported Pt- and EAM-based catalysts by 2.5–6.2x. Technoeconomic and life-cycle analyses reveal naphtha from LDPE hydrocracking is economically and environmentally competitive to fossil-fuel-derived naphtha. These advancements pave the way for the industrial implementation of earth-abundant Ni-based catalysts in polyolefin hydrocracking, followed by retrofitting steam crackers to address plastics waste at scale.

Modelling and Simulation Studies on the Characteristic Behaviour of Macroalgae Derived Bio-Oil

Abstract With the expanding need for renewable and sustainable energy resources, the demand for biomass derived bio-oil particularly microalgae or macroalgae based bio-oil is growing. In this regard, understanding the characteristics of bio-oil as a function of several influencing operational parameters is essential. In this study modelling and simulation technique based on Aspen HYSYS was applied to investigate the characteristics of macroalgae Ulva prolifera derived bio-oil from Hydrothermal Liquefaction (HTL) process as a function of the influencing parameters like temperature, kinematic viscosity, and weight percent of the bio-oil assay, cut yield behaviour, and standard liquid density. Modelling and simulation help to optimise the process parameters and design the process layout for large-scale production. According to the simulation results the cut yield of off gases, light naphtha, heavy naphtha, light distillate, heavy distillate, gas oil and residues are shown at specific final boiling point (FBP) temperatures of 70 °C, 70 °C - 110 °C, 110 °C - 221.1 °C, 221.1 °C - 304.4 °C, 304.4 °C - 371.1 °C, 371.1 °C - 537.8 °C and 537.7 °C respectively. Whereas, above a temperature of 300 °C, the weight percentage of aromatic components increased steadily. The increase in percentage composition of the aromatic components is due to the reduction of the paraffinic components. The density of the liquid bio-oil was steadily increasing until a temperature of 200 °C.

Production of low phenolic naphtha-rich biocrude through co-hydrothermal liquefaction of fecal sludge and organic solid waste using water-ethanol co-solvent

Biocrude production from wet waste through hydrothermal liquefaction (HTL) has become a hotspot for researchers that serves as an alternative to fossil fuel, reducing greenhouse gas emissions and promoting waste to energy approach. However, higher phenolic compounds in hydrothermal liquefaction-derived biocrude have raised concerns about its quality. This study focuses on the production of low phenolic naphtha-rich biocrude through co-liquefaction (320 °C and 60 min) of fecal sludge (FS) and organic solid waste (OSW), two major wet streams by optimizing feedstock (1:0, 1:1, 0:1) and water-ethanol co-solvent (1:0, 3:1, 1:1, 1:3, 0:1). The results revealed that the highest biocrude yield of 55.7 % was achieved at 1:1 (FS: OSW) feedstock and 1:1 (water: ethanol) co-solvent with a heating value of 37.5 MJ/kg, indicating its potentiality to replace petrocrude (42–49 MJ/kg). Notably, produced biocrude is enriched with a lighter fraction (C < 20) of 90 % (85 % naphtha and 5 % jet fuel). The composition of the biocrude comprises 58 % ester, 25 % hydrocarbon, 15 % organic acid, and <1 % phenol, which ensures the least amount of phenolic compounds due to the replacement of the –OH group by the more stable ethoxy group, leading to increased naphtha yield and the absence of phenolic toxicity. Furthermore, the highest API value was recorded at 23.3, which emphasizes its similarity to conventional petroleum API gravity (medium-lighter crude). This energy-positive system (energy recovery 88 % and energy consumption ratio 0.38) could generate revenue of US$ 550 per metric ton of feedstock, suggesting the potentiality of commercialization and contributing to sustainable green energy production.

Production of Light Naphtha by Flash Distillation of Crude Oil

The escalating global demand for sustainable, renewable energy sources has catalyzed research into advanced refining processes, particularly focusing on the generation of essential raw materials like light naphtha. This paper delves into the production of light naphtha via the flash distillation of crude oil, underlining its critical role in fulfilling the petrochemical industry's requirements. The research delineates the fundamentals of flash distillation, incorporating both physical and mathematical models, with a specific emphasis on Raoult's Law, to demystify the hydrocarbon separation process in crude oil. The mathematical framework encompasses material and energy balances, coupled with the application of liquid-vapor equilibrium equations, thereby shedding light on the thermodynamic principles steering this procedure. The progression of this study involved analyzing the distillation curve of the referenced crude oil and identifying the pseudo-components representative of the involved hydrocarbons. Utilizing the DWSIM commercial simulator, the flash distillation process of Nemba crude oil was simulated, taking into account diverse operational conditions and thermodynamic models. The outcomes were juxtaposed with industrial datasets, demonstrating a significant alignment and affirming the simulation's predictive efficacy. A parametric sensitivity analysis was conducted to refine light naphtha yield, elucidating the effect of variables like the temperature of crude oil feed and naphtha separator feed on the process efficiency. The response surface methodology underscored the feasibility of augmenting naphtha production under certain conditions. Furthermore, this study assessed the impacts of employing two distinct thermodynamic models – the Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) equations of state. This analysis revealed minimal discrepancies in physical parameters, confirming the simulation's robustness and the reliability of both models. The findings of this paper validate the efficacy of flash distillation in light naphtha production, with numerical simulation emerging as a potent tool for enhancing process optimization and predictive analysis. These insights not only contribute to a deeper understanding of environmental sustainability but also offer strategies for maximizing light naphtha production in the oil industry. In conclusion, the results from this investigation significantly advance our comprehension of phase equilibrium profiles and their relationship with the applied thermodynamic state equations, thereby enriching the quality of the results.

Hierarchical Y zeolite with accessible intracrystalline mesopores and enhanced hydrocracking performances via sequential multi-carboxyl acid and fluoroborate post-treatments

Hierarchical Y zeolite that combines the intrinsic microporosity with mesoporosity can alleviate diffusion limitation in hydrocracking catalyst. In this study, hierarchical Y zeolites with abundant mesopores that connect the interior of the zeolite crystals to the external surface were successfully synthesized by post-synthesis dealumination using citric acid (C6H8O7) and/or ammonium tetrafluoroborate (NH4BF4) as agents. The results show that C6H8O7 can effectively extraction framework aluminum species (FALs), while NH4BF4 mainly interacts with extra framework aluminum species (EFALs). Via sequentially adopting C6H8O7 and NH4BF4 (denoted as DAY-C-F), such interconnected mesopores can be effectively introduced without sacrificing the zeolite crystallinity. The results of the scaled-up hierarchical Y zeolite reveal that the above mentioned post-treatment strategy is feasible and reproducible for potential industrial manufacturing and applications. The hydrocracking test results reveal that the naphtha yield for the catalyst derived from the C6H8O7-NH4BF4 sequentially treated USY is higher than that of the counterpart made from commercial USY.

Catalyst grading technology for promoting the diesel hydrocracking to naphtha

This paper reports the application of multi-component hydrocracking catalyst grading technology in diesel hydrocracking system to increase naphtha, and studies the influence of catalyst systems with different number of graded beds on the reaction process of diesel hydrocracking. Three hydrocracking catalysts with different physicochemical properties as gradation components, the diesel hydrocracking reaction on catalyst systems of one-component, two-component and three-component graded beds with different loading sequences are carried out and evaluated, respectively. The catalytic mechanism of the multi-component grading system is analyzed. The results show that, with the increase of the number of grading beds, the space velocity of reaction on each catalyst increases, which can effectively control the overreaction process; along the flow direction of feedstock, the loading sequences of catalysts with acidity decreasing and pore properties increasing can satisfy the demand of different catalytic activity for the conversion of reactant with changing composition to naphtha, which has a guiding role in the conversion of feedstock to target products. Therefore, the conversion of diesel, the selectivity and yield of naphtha all increase significantly on the multi-component catalyst system. The research on the grading technology of multi-component catalysts is of great significance to the promotion and application of catalyst systems in various catalytic fields.

Evaluation of Synthesized Pt/HY-H- Mordenite Composite Catalyst for Isomerization of Light Naphtha

This work deals with a composite catalyst preparation, Pt/HY-H-Mordenite, for isomerization of Iraqi light naphtha produced from Baiji North Refinery in a pilot plant fixed bed reactor under operating conditions with the following ranges: temperature 150–250 °C, LHSV 2.46–4.7 hr-1, pressure 6 bar, and hydrogen to hydrocarbon ratio 3.7 mol/mol. The prepared nano-silica, Na-mordenite, H-mordenite, and Pt/HY-H-Mordenite catalysts were described by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) surface area analysis. The investigation results showed that the light naphtha isomerization conversion and yield increased with increasing the temperature and decreasing the liquid-hour space velocity. The highest conversion and yield, obtained at 250 °C and LHSV of 2.46 hr-1, were 89.38% and 76.36%, respectively.

Converting Plastic Wastes to Naphtha for Closing the Plastic Loop.

To solve the serious environmental problem and huge resource waste of plastic pollution, we report a tandem catalytic conversion of low-density polyethylene (LDPE) into naphtha, the key feedstock for renewable plastic production. Using β zeolite and silicalite-1-encapsulated Pt nanoparticles (Pt@S-1), a naphtha yield of 89.5% is obtained with 96.8% selectivity of C5-C9 hydrocarbons at 250 °C. The acid sites crack long-chain LDPE into olefin intermediates, which diffuse within the channels of Pt@S-1 to encounter Pt nanoparticles. The hydrogenation over confined metal matches cracking steps by selectively shipping the olefins with right size, and the rapid diffusion boosts the formation of narrow-distributed alkanes. A conceptual upgrading indicates it is suitable for closing the plastic loop, with a significant energy saving of 15% and 30% reduced greenhouse gas emissions.

Hybrid Gasoline Production from Black Liquor through Coprocessing

A new route is presented as a stepwise upgrading process from black liquor issued from the kraft process to hybrid gasoline: (i) hydrothermal liquefaction (HTL) to produce biocrude, (ii) removal of alkaline metal salts, (iii) hydrodeoxygenation (HDO) for oxygen removal and decrease of molar weight, and finally (iv) coprocessing with vacuum gas oil (VGO) by catalytic cracking to produce gasoline as a second-generation transportation biofuel. A high degree of deoxygenation was found to be quite beneficial to the further cracking of the refined crude oil into gasoline fractions. Thus, for this coprocessing step, it was found that, by limiting the percentage of added pretreated biocrude to about 10 wt %, high naphtha yields (45% compared to 48% for pure VGO cracking) were maintained, and without a significant change in the coke yield. This result is promising since naphtha, the gasoline-rich fraction, is the main target product in FCC. More research is needed in the detailed characterization of the coprocessing products and in checking the quality and compatibility of the hybrid fuel with gasoline standards. Further optimization in the HTL and HDO steps can likely be achieved, possibly allowing coprocessing of larger quantities of HDO biocrude than 10 wt %.

Kinetic modeling of the hydrocracking of polystyrene blended with vacuum gasoil

The kinetic modeling of the hydrocracking of a mixture of polystyrene (PS) and vacuum gasoil (VGO) over a PtPd/HY catalyst has been carried out. The reactions have been performed in a batch reactor under the following conditions: 380–420 °C; 80 bar; content of PS in the feed, 10 wt%; catalyst/feed ratio, 0.1 in mass; and time, 30–300 min. Different reaction networks and kinetic models have been studied, in which the evolution of product distribution (unconverted PS, dry gas, liquefied petroleum gases, naphtha, light cycle oil, heavy cycle oil and coke) with the extent of time has been quantified by considering three different simultaneous deactivation mechanisms (plastic fouling, coke deposition and metal poisoning). The kinetic model selected (based on a 7-lump reaction network) has been used for performing a parametric study, determining that 400 °C and 180 min are the optimal conditions for maximizing the yield of naphtha (35 wt%) at the same time that PS is totally converted. This original kinetic model may act as a basis for scaling-up studies focused on the large-scale valorization of waste plastics by co-feeding them into a hydrocracking unit of a Waste-Refinery.

Enhancing the performance of a PtPd/HY catalyst for HDPE/VGO hydrocracking through zeolite desilication

The valorization of post-consumer waste plastic in a refinery is an attractive initiative to avoid environmental problems caused by the poor plastic waste management. The modification of a bifunctional PtPd/HY catalyst through desilication (using NaOH) of the ultrastable HY zeolite has been carried out to upgrade waste plastic (high-density polyethylene (HDPE)) dissolved in a secondary refinery stream (vacuum gas oil (VGO)) through hydrocracking. Three different catalysts have been studied: the parent (Cat-A), undergoing a desilication cycle (Cat-B), and subjected to two cycles of desilication (Cat-C). The characterization techniques employed have been: N2 adsorption–desorption, TEM, ICP-AES, tert-butylamine-TPD, pyridine FTIR, WDXRF, XRD and TPO. The hydrocracking tests have been carried out in a semi-batch reactor at: 440 °C; 80 bar; catalyst to feed ratio, 0.1 gcat (gfeed)–1; HDPE to feed ratio, 0.2 gHDPE (gfeed)–1; and reaction time, 2 h. The products have been fractioned according to their boiling point range in: gas, naphtha, light cycle oil, heavy cycle oil and coke. The composition of each fraction has been determined in terms of concentration of paraffins, olefins, naphthenes and (mono-, di- and poly-) aromatics. The results show that alkaline treated catalysts enhance the fuel production, with high HDPE and HCO conversions. The Cat-C (the one submitted to two desilication cycles) has displayed the greatest performance, reducing by half the gas yield and increasing the naphtha yield by 51 wt% respect to those obtained with the parent catalyst (Cat-A). Moreover, it has decreased the coke deposition and the coke formed has been less developed.

Effect of FCC light diesel blending ratio on properties of refined products in diesel hydrofining unit

Under the background of product oil market surplus and Double carbon target, reducing refined oil and increasing chemical feedstock can speed up the adjustment of industrial structure and improve the core competitiveness of enterprises. In order to reduce diesel and gasoline ratio and increase naphtha production to extend chemical industrial chain, the influence of FCC light diesel blending ratio on properties and yield of refined products was studied in this paper. The experiment result showed naphtha yield decreased and diesel yield increased with increasing of the blending ratio of FCC light diesel in straight run diesel. The desulfurization effect of refined diesel is better, and diesel CI decreased but it still can meet the quality requirements of products. The content of alkane in naphtha decreased while the aromatic latencies increased, so naphtha is suitable for catalytic reforming. The optimum blending ratio of FCC light diesel is 12%. While naphtha is used as cracking feedstock FCC light diesel blending ratio should be reduced. The experimental results can lay a foundation for further research on straight-run diesel blending with other oils, and provide technical support and reference data for feedstock adjustment of similar units.

Influence of ASA composition on its supported Mo catalyst performance for the slurry-phase hydrocracking of vacuum residue

To deeply illuminate the effect of ASA composition on its corresponding Mo catalyst properties and performance for the slurry-phase hydrocracking of vacuum residue, the amorphous silica-alumina (ASA) samples with the various ratios of Al to Si were successfully synthesized by a simple co-precipitation method, which have the different acid properties and pore structure, especially ASA-1 with lowest ratio of Al to Si owning the largest number of B acid sites and the highest volume of mesoporous. Additionally, the Mo catalyst supported on ASA-4 possesses the highest dispersion of MoS2 slabs and largest amount of Mo atoms located at the edge sites among all the catalyst, possibly due to the appropriate surface properties of ASA-4 derived from the ratio of Al to Si, it demonstrates that the most exposure Mo active sites are present on Mo/ASA-4 catalyst. The hydrocracking evaluation results show that the VR conversion over the different catalysts are similar, it may be ascribed to the variation of acid properties and pore structure insufficient to change VR cracking pathway because of the low catalyst dosage. Furthermore, the Mo/ASA-4 catalyst exhibits the higher yield of naphtha and middle distillate and inversely the lower yield of gas and coke in comparison with other catalysts, it should be attributed that the higher hydrogenation activity derived from the more exposure Mo active sites can efficiently restrain the over-cracking of the intermediate product and aggregation of the polycyclic aromatic hydrocarbon in the hydrocracking process.

Hydrogen Pressure as a Key Parameter to Control the Quality of the Naphtha Produced in the Hydrocracking of an HDPE/VGO Blend

The hydrocracking of high-density polyethylene (HDPE) blended with vacuum gas oil (VGO) has been studied to assess the effect of H2 pressure on the yield and composition of the products and with the aim of obtaining commercial fuels, mainly naphtha. The experiments have been performed using a PtPd/HY catalyst in a semibatch reactor under the following conditions: H2 pressure, 20–110 bar; 440 °C; catalyst to feed ratio, 0.1 gcat (gfeed)−1; HDPE to total feed ratio, 0.2 gHDPE (gfeed)−1; and reaction time, 2 h. The composition of the main fractions produced (gas, naphtha, and light cycle oil) reveals the interest in carrying out the process at 110 bar. Thus, conversions of 96 and 79% for the removal of heavy hydrocarbons and the removal of HDPE molecules have been obtained, respectively, together with a yield of naphtha of 53.4 wt%. This naphtha is mainly paraffinic, and it has a RON of 91.5 (within the commercial standards). Furthermore, three fractions have been observed in the analysis (temperature-programmed oxidation) of the coke. This analysis reveals that at 110 bar, the coke retained in the HY zeolite cages is less developed and burns at a moderate temperature.

Assessing the feasibility of chemical recycling via steam cracking of untreated plastic waste pyrolysis oils: Feedstock impurities, product yields and coke formation

Chemical recycling of plastic waste to base chemicals via pyrolysis and subsequent steam cracking of pyrolysis oils shows great potential to overcome the limitations in present means of plastic waste recycling. In this scenario, the largest concern is the feasibility. Are plastic waste pyrolysis products acceptable steam cracking feedstocks in terms of composition, product yields and coke formation? In this work, steam cracking of two post-consumer plastic waste pyrolysis oils blended with fossil naphtha was performed in a continuous bench-scale unit without prior treatment. Product yields and radiant coil coke formation were benchmarked to fossil naphtha as an industrial feedstock. Additionally, the plastic waste pyrolysis oils were thoroughly characterized. Analyses included two dimensional gas chromatography coupled to a flame ionization detector for the detailed hydrocarbon composition as well as specific analyses for heteroatoms, halogens and metals. It was found that both pyrolysis oils are rich in olefins (∼48 wt%) and that the main impurities are nitrogen, oxygen, chlorine, bromine, aluminum, calcium and sodium.Steam cracking of the plastic waste derived feedstocks led to ethylene yields of ∼23 wt% at a coil outlet temperature of 820 °C and ∼28 wt% at 850 °C, exceeding the ethylene yield of pure naphtha at both conditions (∼22 wt% and ∼27 wt%, respectively). High amounts of heavy products were formed when steam cracking both pyrolysis oils, respectively. Furthermore, a substantial coking tendency was observed for the more contaminated pyrolysis oil, indicating that next to unsaturated hydrocarbons, contaminants are a strong driver for coke formation.

Kinetic modeling for the catalytic cracking of tires pyrolysis oil

The parameters of a 6-lump kinetic model for the catalytic cracking of tire pyrolysis oil (TPO) in conditions of the industrial fluid catalytic cracking (FCC) unit have been computed. The experiments have been carried out in a riser simulator reactor, on a commercial equilibrium catalyst at the following conditions: 500–560 °C; catalyst/oil ratio (C/O), 3–7 gcat gTPO-1; and reaction time, 1–10 s. The most significant catalytic steps for conversion levels below 80% are those in which the heavy cycle oil (HCO) lump is involved, either cracked to form light cycle oil (LCO), naphtha, liquefied petroleum gases (LPG), dry gas or condensed to coke. For higher levels of conversion, LCO and naphtha lump over-crack causing exponential increases in the yields of LPG, dry gas and coke. It should be highlighted the high yield of naphtha obtained (48 wt%) for a conversion of 90% at 530 °C. It is also remarkable the low deactivation level by coke deposition, since the coke formed on the acid sites of the catalyst is not much condensed. The results are of great interest for the design or reactors ad hoc for the catalytic cracking of TPO in conditions similar to those of industrial FCC unit, as well as for its feeding to a commercial unit within the strategy involved in the Waste Refinery.

Study on direct conversion of Naomaohu coal pyrolysis heavy oil to aromatics

The pyrolysis tar from Naomaohu coal was separated by distillation apparatus. Four components of heavy oil above 320°C were analyzed. The result showed the colloid content was 28.84% and the asphaltene content was 35.12%, and both were difficult to convert in hydrogenation. 13C-NMR results showed that the relative molar ratio of aromatic carbon in heavy oil was 71.16%, which indicated that aromatic compounds in heavy fraction were dominant. The heavy fraction was treated by suspension bed and fixed bed cracking. The asphaltene and colloid were almost completely converted. The yield of naphtha with boiling point below 180°C was 66.95%, and the diesel with boiling point higher than 180°C was 17.84%. Oxygen, nitrogen and sulfur contained in heteroatoms were almost completely removed. Catalytic reforming of naphtha was carried out. The results showed that the number of cycloalkanes decreased by 60.23%, and the number of aromatics increased by 65.8%, which indicated that the dehydrogenation and aromatization of cycloalkanes occurred mainly. While the number of n-alkanes decreased by 13.42%, which indicated that the isomerization and cyclization of n-alkanes occurred simultaneously. The catalytic reforming oil contained more benzene, toluene, xylene and ethylbenzene, and the contents were 11.97%, 23.15%, 21.43% and 3.48% respectively. In the direct conversion process of heavy oil from coal pyrolysis, the transmissibility of basic structural units of coal was significantly reflected.

Aluminum phosphate as active matrix of fluid catalytic cracking catalysts: Y zeolite stabilization

The development of new matrices can improve the hydrothermal stability of fluid catalytic cracking catalysts and provide better selectivity to cracking products. Amorphous, mesoporous and stoichiometric aluminum phosphate (AlPO4) was investigated as active matrix to achieve these purposes. In its gel form, the material was initially added to ultra-stabilized Y zeolite to generate composites with mass ratio of about 1:1. The interaction between AlPO4 and Y zeolite avoided AlPO4 crystallization during steaming and increased framework aluminum retention, preserving more Brönsted acid sites. A spray-dried catalyst containing AlPO4 was steam deactivated and tested by vacuum gas oil cracking, being compared with an alumina-containing catalyst and a reference without active matrix. AlPO4-containing catalyst presented tolerance to contaminant metals, higher selectivity to naphtha yields and exhibited a higher hydrogen transfer reaction rate, leading to the increase in isoparaffins and aromatics yields and the increase in the motor octane number in the cracked naphtha.

Light Paraffinic Naphtha to BTX Aromatics over Metal‐Modified Pt/ZSM‐5

AbstractWe investigated the conversion of light paraffinic naphtha (C5‐C6) into BTX (benzene, toluene, and xylenes) aromatics using 1.0 wt % Pt‐M/ZSM‐5 (modifier M=1 wt% Zn, 2 wt % of Fe, La, Ga) prepared using wet‐impregnation method. The effects of Pt and modifier on light naphtha conversion, yield and aromatic selectivity (benzene, toluene, xylene, C9+ aromatics) were studied in fixed‐bed flow reactor in atmospheric pressure, at 550 °C, and WHSV 1.0 h−1. Catalytic efficiency of modified Pt or Pt‐M ZSM‐5 catalysts has been equated to conventional ZSM‐5 [Si/Al2=30] catalyst. While the yield of total aromatics was slightly increased over Pt/ZSM‐5 comparison to parent ZSM‐5 from 32 wt % to 37 wt %, the value for in situ formed mesoporous Pt‐Ga/ZSM‐5 was significantly improved reaching 60 wt %. The higher selectivity to aromatics is attributed to the induced mesoporous volumes and dehydrogenation activity of Ga species. These species associated with Pt were effective in the conversion of light naphtha to olefins, which later converted into aromatics by secondary reactions: cracking, isomerization and dimerization. The Pt‐Ga/ZSM‐5 showed good stability toward the selective production of aromatics at a low toluene/benzene ratio ∼0.5 due to Pt component.