Petroleum Chemistry最新文献

This study investigates a silica-gel-supported cobalt catalyst for synthesizing long-chain hydrocarbons (C₁₉₊) from CO and H₂. The process conditions were varied within the following ranges: pressure, 1.5–3.5 MPa; gas hourly space velocity (GHSV), 300–830 h^–1; H₂/CO ratio, 2.0–2.3; and temperature, 187–213°C. Catalytic testing revealed a correlation between the catalyst deactivation rate and the content of C₁₉₊ hydrocarbons in the products. When the C₁₉₊ content increased from approximately 40 to 55 wt %, the deactivation rate increased more than tenfold. Under optimized conditions (H₂/CO = 2.3, P = 2.0 MPa, T = 193°C), the C₁₉₊ content reached ~46–50 wt %, and the deactivation rate was minimized. A long-term stability test over 500 h was used to project a catalyst cycle length, which was found to be at least 4000 h. The study results provide a foundation for optimizing Fischer–Tropsch process conditions to maximize catalyst lifetime and selectivity toward heavy hydrocarbons, supporting the recommendation of the proposed catalyst for industrial implementation.

This review analyzes existing strategies for intensifying bioalcohol production via acetone–butanol–ethanol (ABE) fermentation focusing on the use of membrane concentration techniques. It also discusses the potential applications of the resulting concentrates as feedstocks for low-carbon fuels and petrochemicals. The review comprises three parts: (1) the current state of ABE fermentation technology, including its fundamental principles as they relate to biomass type; (2) membrane-based separation techniques for concentrating target fermentation products, with a primary focus on pervaporation and promising membrane types and materials; and (3) the downstream processing of ABE concentrates into high-value-added petrochemicals.

A detailed kinetic model based on the NUI Galway mechanism for light hydrocarbon oxidation was used to investigate the effects of pressure on the non-catalytic conversion of methane in various gas atmospheres (Ar, H₂, CO, CO₂, H₂O). The study also evaluated the impact of H₂O addition on the conversion of CH₄ in mixtures with H₂ and CO. For CH₄ mixed with Ar, CO, or H₂, the methane pyrolysis rate exhibits a power-law dependence on pressure (W = APⁿ), with the exponent n ranging from ~0.4 to ~0.65 in the 1400–1800 K temperature range. The achievable CH₄ conversion decreases significantly with rising pressure, particularly for CH₄–H₂ mixtures. For the non-catalytic conversion of CH₄ in mixtures with H₂O and CO₂, the initial pyrolysis rate is similar to that in an argon atmosphere. At high pressures, however, the CH₄ concentration profile subsequently passes through a rising region. This is attributed to the interaction of C₂H₂ and CO products with H₂O, which generates additional H₂ and consequently shifts the equilibrium of the reaction system (2CH₄ ↔ C₂H₄ + 2H₂ ↔ C₂H₂ + H₂) to the left.

A series of platinum catalysts were synthesized using Al₂O₃ supports modified with Na⁺ and Mg²⁺ cations (2 wt %). The phase compositions, textural properties, acidity, and catalytic performance of these catalysts in the non-oxidative dehydrogenation of propane were characterized by X-ray diffraction (XRD), low-temperature nitrogen adsorption–desorption, and temperature-programmed desorption of ammonia (NH₃-TPD) and carbon dioxide (CO₂-TPD). The catalytic activity decreased in the order: 2Mg/Al₂O₃ > Al₂O₃ > 2Na/Al₂O₃. The study demonstrates a correlation between the acid–base properties of the catalyst supports and the propane conversion pathway during dehydrogenation.

Hierarchical Al-BEA zeolites were prepared by hydrothermal treatment of a concentrated reaction mixture containing a highly dispersed silicon source. The hierarchical zeolites obtained consist of aggregated crystallites and contain, along with zeolite micropores, also intercrystallite mesopores. With a decrease in the H₂O/Si ratio from 15 to 5.5 and in the Si/Al ratio from 12.5 to 10, the crystallite size decreases to 13 nm. This is accompanied by an increase in the mesopore volume and in the external and total specific surface area of the samples. The catalytic properties of the hierarchical zeolites in the α-pinene isomerization were studied. The initial rate of the α-pinene consumption increases with an increase in the concentration of strong Brønsted acid sites and is the highest for the commercial Al-BEA zeolite with the ratio Si/Al = 12.5. The α-pinene conversion increases with an increase in the external specific surface area of the zeolites and reaches 91% after 24 h of the reaction for the hierarchical zeolite with the ratio Si/Al = 9, prepared in the concentrated reaction mixture. The selectivity of camphene formation decreases and the selectivity of limonene formation increases with an increase in the Brønsted-to-Lewis acid site ratio. The highest camphene and limonene yields, equal to 45 and 31%, respectively, are reached when using the sample with the most developed mesoporosity and the Brønsted-to-Lewis acid site ratio of 0.9.

Micropore diffusion limitations impair the performance of SAPO-11-supported bifunctional catalysts in the hydroisomerization of long-chain n-paraffins (C₇₊), reducing their activity, selectivity, and stability. These diffusion constraints can be mitigated by introducing secondary porosity and reducing the crystallite size. This study investigates the effect of the silica content (varied via the SiO₂/Al₂O₃ molar ratio) on these parameters. The physicochemical properties of the synthesized samples were characterized by XRD, SEM, ²⁹Si MAS NMR, NH₃-TPD, and some other methods. Increasing the SiO₂/Al₂O₃ ratio was shown to reduce the size of primary nanocrystals and generate a well-developed mesoporous structure. At SiO₂/Al₂O₃ ratios ≥ 0.3, the extent of silicon incorporation and the concentration of acid sites reach a maximum, while a decrease in crystallinity was observed. The most developed hierarchical porous structure, featuring an external surface area of 67 m²/g and a mesopore volume of 0.19 cm³/g, was achieved at a SiO₂/Al₂O₃ ratio of 0.1. In the hydroisomerization of n-hexadecane, the sample synthesized with a SiO₂/Al₂O₃ ratio of 0.3—which exhibited an optimal combination of high acidity and small nanocrystal size—achieved the highest conversion and i-C₁₆ selectivity. Therefore, fine-tuning the silica content is an effective strategy for the targeted design of high-performance hydroisomerization catalysts.

The effect of the weight hourly space velocity of methanol on the deactivation of SAPO-34 silicoaluminophosphate in methanol conversion to hydrocarbons has been investigated, and the nature of coke deposits formed on completely deactivated zeolite samples in the course of operation in different reactors has been examined. The deactivation order with respect to methanol is 1 in fluidized-bed, and slurry reactors, while it is 1.2 in the fixed-bed reactor. The presence of polydimethylsiloxane as the reaction medium in a slurry reactor decreases the time of the stable catalyst operation by a factor of 2 relative to the fluidised-bed reactor irrespective of the feed rate. The specific conditions at which different types of reactors demonstrate a more stable operation in this process have been calculated.

Zeolite ZSM-48 is an efficient acidic catalyst support for the hydroisomerization of higher (C₁₆₊) n-paraffins, but its industrial application is hindered by the high cost of conventional structure-directing agents (SDAs). This study develops a more economical synthesis method using hexamethylenediamine (HDA) as an affordable SDA. A series of high-crystallinity zeolite samples (SiO₂/Al₂O₃ = 160–200) were synthesized hydrothermally. After loading with 0.5 wt % Pt, their physicochemical properties and catalytic performance were evaluated in the hydroisomerization of n-hexadecane at 3.0 MPa. The initial alkali content in the reaction gel was identified as a critical parameter controlling crystallization selectivity, crystal morphology, and crystallinity. The sample synthesized with low alkali content exhibited the highest performance, achieving 90% n-hexadecane conversion at 320°C with a yield of desired isomers up to 62%. This demonstrates the high potential of HDA for crystallizing selective ZSM-48 and for preparing promising catalysts for the hydroisomerization of higher n-paraffins.

The second part of the review (Bruter, D.V. and Konnov, S.V., Petr. Chem., 2025, vol. 65, pp. 331–368) is dedicated to the advances in the development of propane dehydrogenation catalysts based on cobalt-, gallium-, indium-, and zinc-containing zeolites. The existing strategies of the synthesis of materials based on molecular sieves are analyzed. In some cases, to reflect more completely recent advances in the development of metal-containing zeolite catalysts for dehydrogenation of lower alkanes, examples concerning ethane dehydrogenation, which is performed under harsher conditions are also presented, as well as oxidative dehydrogenation of lower alkanes with CO₂. Particular attention is paid to studies of structure–property and synthesis–structure relationships. A brief conclusion summarizing the main results and unresolved problems is provided for each catalyst type in the end of the corresponding section. Conclusions regarding the most promising strategies for the development of industrial catalysts of new generation are presented in the final part of the review.

This review provides an analysis of the physicochemical properties and catalytic performance of ZSM-48 zeolites prepared using various inorganic reagents, templates, and seeds under varying synthesis conditions (e.g., reaction temperature and time). The paper discusses the catalytic performance of these zeolites in various reactions, including cracking, hydroisomerization, and methanol-to-hydrocarbons (MTH) conversion.