Applied Petrochemical Research最新文献

A series of Ni/SBA-15 catalysts were prepared by impregnation method for the hydrogenation of levulinic acid (LA) to γ-valerolactone in a fixed bed reactor at atmospheric pressure. The catalysts were characterized by XRD, TPR, AAS, Pulse chemisorption, SEM-EDAX, TEM, BET Surface area and XPS. The catalyst 30?wt% Ni/SBA-15 exhibited excellent catalytic performance (97% yield) at 250?°C due to the presence of superior number of active surface Ni species. While 30?wt% Ni/SiO₂ catalyst showed lower catalytic activity (87% yield) at about similar conversion. The co-feeding of formic acid (FA) and water (impurities) with levulinic acid was also evaluated over 30?wt% Ni/SBA-15 which yielded excellent levulinic acid conversion. The noteworthy results were obtained at a molar ratio of FA/LA?=?5. The constant catalytic activity during 10?h experiment with an external H₂ flow has showed the sturdiness of the Ni/SBA-15 catalyst.?On the other hand, a slight decrease in conversion as well as yield during the time-on-stream in the absence of external H₂ flow was attributed to the accumulation of carbon species on the catalyst surface.

The FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8?kg/s mass flow rate of catalyst and 53.4?kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95?wt%. When compared with the base case simulation value of 4.59?wt% propylene yield, the maximized propylene yield is increased by 95%.

This study focuses on the modification of ZSM-5 in order to enhance the catalytic cracking of refinery naphtha to produce light olefins. ZSM-5 was metal modified using different loadings (0.5–5?wt%) of Fe and Cr via the impregnation method. The metal modified ZSM-5 samples are compared and the effect of metal loading on the physicochemical properties and catalytic performance is investigated. Fe and Cr modification had an effect on both the physicochemical properties of the catalysts as well as catalytic activity and selectivity. Metal loading caused a decrease in the specific surface area which decreased further with increased metal loading. Fe had a greater effect on the total acidity in particular strong acid sites when compared to Cr. The optimum Fe loading was established which promoted selectivity to olefins, in particular propylene. Fe also had a dominant effect on the P/E ratio of which a remarkable ratio of five was achieved as well as enhanced the stability of the catalyst. Cr was found to be a good promoter for selectivity to BTX products with a two-fold increase observed when compared to Fe-modified catalysts.

Several catalysts containing metals such as Al, Zr, Ti and Nb were incorporated in SBA-15 with Si/M ratio?=?20 using the hydrothermal process. These catalysts were evaluated for their reactivity during acid-catalyzed condensation of glycerol with acetone to yield a mixture of branched compounds, namely (2,2-dimethyl- [1,3] dioxane-4-yl)-methanol (solketal) and 2,2-dimethyl- [1,3] dioxane-5-ol, which are being used as fuel additives. The synthesised catalyst samples were characterized by ICP-AES analysis, N₂ adsorption–desorption measurements, X-ray diffraction, FT-IR, SEM–EDX, UV–visible diffuse reflectance spectroscopy, TPD of ammonia and ex situ pyridine-adsorbed FT-IR spectroscopy. The various characterization results confirm that metal oxides were incorporated in the pore wall of the SBA-15 matrices. The results of NH₃-TPD and ex situ adsorbed pyridine FT-IR analyses showed that the acidity of the samples increased after incorporation of metal into the pure SBA-15 samples. Among various metals incorporated into the SBA-15, the Nb–SBA-15 (Si/Nb?=?20) showed higher catalytic activity toward the acetalization of glycerol in liquid phase compared to that of other samples investigated. Under the optimal reaction conditions, the Nb–SBA-15 (Si/Nb?=?20) exhibited 95% glycerol conversion with 100% solketal selectivity. The catalyst reusability studies indicated that the Nb–SBA-15 sample is regenerable and highly stable in the acetalization of glycerol.

Autoxidation is a conversion pathway that has the potential to add value to multinuclear aromatic-rich coal liquids, heavy oils and bitumens, which are typically considered low-value liquids. In particular, autoxidation of these heavy materials could lead to products that may have petrochemical values, e.g., lubricity improvers and emulsifiers. Proper assessment of an oxidative transformation to ring-open the multinuclear aromatics present in heavy feeds relies on the understanding of the fundamentals of aromatic oxidation. This work reviews the selective oxidation chemistry of atoms that form part of an aromatic ring structure using oxygen (O₂) as oxidant, i.e., the oxidation of aromatic carbons as well as heteroatoms contained in an aromatic ring. Examples of industrially relevant oxidations of aromatic and heterocyclic aromatic hydrocarbons are provided. The requirements to produce oxygenates involving the selective cleavage of the ring C–C bonds, as well as competing non-selective oxidation reactions are discussed. On the other hand, the Clar formalism, i.e., a rule that describes the stability of polycyclic systems, assists the interpretation of the reactivity of multinuclear aromatics towards oxidation. Two aspects are developed. First, since the interaction of oxygen with aromatic hydrocarbons depends on their structure, oxidation chemistries which are fundamentally different are possible, namely, transannular oxygen addition, oxygen addition to a carbon–carbon double bond, or free radical chemistry. Second, hydrogen abstraction is not necessary for the initiation of the oxidation of aromatics compared to that of aliphatics.

Jet fuel is a mixture of different hydrocarbon groups, and the mass contribution of each of these groups toward the overall chemical composition of the fuel dictates the bulk physical properties of the fuel after completion of the refining and blending processes. The fluidity properties of jet fuel mixtures at low temperatures are critical in understanding and mitigating the safety risks and performance attributes of aircraft engines, which may lead to the introduction of more stringent specification limits in the near future. Therefore, in this study the low-temperature viscosity and freeze point properties of jet fuels were investigated by variation of the linear to branched chain paraffin mass ratio, in conjunction with variation of the carbon number distribution according to a mixture by process variables experimental design. Furthermore, response surface models were developed and discussed for the two main fluidity properties of interest and inferences were made from the models for the potential generation of optimal jet fuel mixtures.

The partial oxidation of ethane to ethylene and acetic acid on supported MoVNbPd/TiO₂ (P25 of Degussa) has been investigated. Pd was added?in a nano-metallic form. The catalyst composition was also different from similar studied catalysts. This results in a better selectivity towards acetic acid formation. The reaction was carried out in a tubular reactor at temperature range 225–275?°C, total pressure range 0–200?psig and oxygen percentage in the feed gas of 10–40%. The feed gas contains ethane and oxygen. In this work, we develop a kinetic model for the reaction for the developed catalyst. In this model, we assume that oxidation reactions take place on different sites; ethane oxidation takes place on one site, ethylene oxidation on another site, and CO is oxidized to CO₂ on a third site. The model exhibits good agreement with the experimental data.

The adsorption of hexachloroplatinic acid on Sn-impregnated γ-alumina support in the presence of the competitive chloride ion, as a step in preparation of multi-metallic Pt-based catalyst (such as Pt–Sn/Al₂O₃), was studied. The transient adsorption data were obtained by studying the impregnation of Sn/Al₂O₃ with H₂PtCl₆ in an external recycle packed-bed impregnation system. The effect of important parameters such as pH of the impregnating solution, circulation flow rate, and height/diameter ratio of support bed on competitive adsorption was studied. It was observed that upon increasing pH and decreasing circulation rate, the rate of Pt adsorption as well as axial non-uniformity along the bed was increased. On the other hand, a time lag was observed in bulk adsorbate concentration in certain runs which was attributed to deviation from well-mixed contacting pattern being necessary for a uniform catalyst product. This could be minimized by increasing the recycling flow rates and using appropriate amounts of competitive ion concentration.

Methanol-to-olefin (MTO) reaction was investigated over sonochemically (SAPO-34-U40, SAPO-34-U70, SAPO-34-U100) and hydrothermally (SAPO-34-HT) prepared nanocatalysts. The catalytic performance of prepared samples was investigated over all samples at 450?°C and over SAPO-34-U40 at 350–450?°C temperature range. The higher yield ~?97?wt% (31.4?wt% C₂₌, 49.4?wt% C₃₌ and 16.1?wt% sumC₄₌) of light olefins was obtained at 375?°C on SAPO-34-U40. Physico-chemical properties of catalysts were characterized by XRD, SEM, BET, ICP techniques. XRD analysis showed suitable crystalline structure and SEM images confirmed perfect crystallinity of sonochemically prepared samples. BET analysis indicated remarkable surface area of SAPO-34-U40. The amount of carbon deposits and character of coke was determined by TPO analysis. The higher amount of coke was determined over SAPO-34-HT in comparison to another’s at 450?°C. The character of coke deposited over SAPO-34-U40 was similar for 375–425?°C temperatures.