Catalysis in Industry最新文献

The authors study the possibility of using nickel-containing structured fiberglass catalysts (Ni/GFC) in the hydrogenolysis of gas condensate (GC) to transportable natural gas components to improve the efficiency of GC processing and promote the development of more cost-efficient technologies in the oil and gas industry. Ni/GFC samples with nickel contents of 5, 10, and 15 wt % were synthesized via surface thermosynthesis (STS). A commercial granular catalyst with a nickel content of 16 wt % is used to compare the synthesized catalysts according to their catalytic activity. The highest activity and selectivity to methane in the hydrogenolysis of propane is observed on 10%Ni/GFC catalyst, which is superior in these characteristics to other GFCs and the traditional granular catalyst.

Approaches to producing biochar from microalgae biomass, in particular, those based on the use of pyrolysis, torrefaction, and hydrothermal treatment, are discussed. Data on the textural characteristics of biochars synthesized by different methods are described; the features of their production are considered. It has been found that the content of a particular component in the biomass, depending on the type of microalgae used and conditions for the cultivation and thermal treatment of the biomass (temperature, heating rate, time), affects the textural characteristics of the resulting biochar.

Fluidized bed catalytic combustion is the most environmentally friendly and energy-efficient method for converting various fuels, in particular, low-grade fuels. The technology involves the oxidation of volatile substances on the surface of catalyst particles diluted with an inert material in a fluidized bed. The conventional use of quartz sand as an inert material leads to the accelerated degradation of the catalyst during on-stream use due to abrasion. This study is focused on the effect of the magnesium modification of active spherical Al₂O₃ and the development of a strengthened material (with crushing and abrasion strengths comparable to the values for a deep oxidation catalyst (DOC)) capable of minimizing DOC losses. The modified support is synthesized by impregnating spherical Al₂O₃ pellets with a precursor solution (nitrate and acetate) and subsequently calcining the pellets at 80°C. The resulting pellets are studied by X-ray fluorescence analysis (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES), low-temperature nitrogen adsorption (BET), and scanning electron microscopy (SEM). In addition, the mechanical strength of the pellets and their catalytic activity in CO oxidation are determined. It is found that the strength characteristics of Al₂O₃ linearly increase upon the introduction of magnesium in an amount of 2–9 wt %. The use of the selected material under laboratory conditions provides a threefold decrease in catalyst losses during 4.5-h abrasion compared with losses in the case of using quartz sand.

A way of producing high-octane gasoline from associated petroleum gas (APG) by combining APG aromatization with Fischer–Tropsch (FT) synthesis is proposed. APG aromatization is studied experimentally in a flow setup at a pressure of 0.1 MPa and temperatures of 450–600°C on ZnO/ZSM-5/Al₂O₃ catalyst. It is shown that the conversion of С₃₊ hydrocarbons is greatest in the 550–600°C range of temperatures to reach 22.7–27.8%, while the yield of aromatics is 8.8–10.9%. FT synthesis is studied on hybrid Co-Al₂O₃/SiO₂/ZSM-5/Al₂O₃ catalyst at a temperature of 250°C, a pressure of 1.0 MPa, and GHSV = 1000 h⁻¹. One liter of an experimental synthetic gasoline fraction is produced on a pilot setup to analyze its principal physicochemical properties and possible qualities of utilization. Calculations show that blending the gasoline fraction of FT synthesis with products of APG aromatization allows the octane number to be raised from 78.5 to 92.8 while the density grows from 710 to 778 kg/m³. The proposed engineering solutions can be used for converting APG into high-octane synthetic gasoline on modular Gas-to-Liquids (GTL) units.

Studies on the development of a homogeneous process for the low-temperature oxidation of carbon monoxide in the presence of a platinum group metal + vanadium-containing heteropoly acid (HPA) catalyst system have been described. Optimum reaction conditions to provide the maximum rate of CO oxidation to CO₂ have been determined, features of reaction kinetics have been found, and a mechanism has been proposed. It has been shown that systems based on a Pd^II aqua complex exhibit high activity and productivity; however, they have low stability and are used on stream only at a pH below 1.5. The stability of the catalyst can be increased by the simultaneous introduction of σ- and π-donor ligands into the system; however, the use of a Pt^IV complex in the presence of catalytic amounts of palladium salt in a ratio of 100/1 is more effective. Switching from HPA solutions with a low vanadium atom content (H₇PMo₈V₄O₄₀) to high-vanadium solutions of modified compositions (H₁₀P₃Mo₁₈V₇O₈₄) provides an increase in the activity and productivity of the system, while the shapes of the kinetic curves and the general laws governing CO oxidation are preserved. The combined homogeneous Pt^IV + Pd^II + H₁₀P₃Mo₁₈V₇O₈₄ catalyst remains stable during multicycle use without loss of activity, does not have an induction period in on-stream performance, and can be used at a pH of 0.7−2.5, which simplifies the hardware support of the process.

The use of renewable resources to produce marketable chemicals is an alternative to conventional processes based on petrochemical synthesis. The main approaches to producing organic acids from glucose and cellulose as components of renewable biomass are discussed. Biotechnological approaches to producing glycolic, glutaric, mesaconic, muconic, isobutyric, lactic, 3-hydroxypropionic, succinic, itaconic, and adipic acids are compared with catalytic approaches. It is shown that the biotechnological production of succinic and lactic acids has been implemented on an industrial scale, and a number of other organic acids can be synthesized by biotechnological methods provided that the productivity of their producers is increased.

The catalytic alkylation of benzene with a multicomponent mixture consisting of products from the thermal pyrolysis of higher paraffins and containing a wide fraction of olefins of various structures is studied. Methanesulfonic acid, which has weak corrosion properties compared to industrial catalytic systems, is used as a homogeneous catalyst. Using two-dimensional gas chromatography to analyze the composition of both the initial multicomponent raw material and the products of alkylation allow the selection of the initial process conditions and the correct calculation of such parameters for assessing efficiency as selectivity and conversion. Depending on the raw material, the selectivity to linear alkylbenzene (LAB) is ranged within 82.4–88.3%; for 2-LABs, it is 29.2–41.3% at ~90% olefin conversion.

Results of studying Pt and Pd γ-alumina supported catalysts in the hydrogen oxidation reaction for use in helium concentrate (HC) purification processes were described. The properties of the synthesized catalysts were compared with the properties of a foreign reference catalyst. The “ignition” and deactivation of the catalysts at room temperature in a laboratory reactor using a mixture simulating an HC were studied while simulating conditions at the inlet of an industrial adiabatic reactor; the properties of the catalysts were studied at temperatures of 200, 250, and 300°C under conditions simulating the occurrence of the reaction in the middle zone and at the outlet from an industrial reactor. The secondary hydrogen formation process at temperatures of 250–300°C was studied and attributed to the steam reforming of methane and ethane present in the model mixture simulating HC. The results of the study can be used to develop domestic catalysts for the purification of helium extracted from natural gas.

The activation of highly efficient cobalt catalysts for Fischer–Tropsch synthesis has been studied taking into account the transformation of the resulting structures and the presence of a heat-conducting percolation network of metallic aluminum. The effect of the temperature, process duration, reducing gas composition, and reducing gas hourly space velocity on the degree of reduction and the specific surface area of the active catalyst component has been studied. The above characteristics have been determined by low- and high-temperature oxygen titration on a chromatographic sorption unit and by temperature-programmed reduction. The tests have shown the possibility of decreasing the temperature and the hydrogen concentration in the gas to achieve the required parameters during reduction to synthesize a highly efficient catalyst system. The parameters of this system in Fischer–Tropsch synthesis (CO conversion, liquid hydrocarbon productivity) are comparable to or better than for a catalyst reduced under standard conditions.

The synthesis of C₅–C₁₈ alkenes in the presence of a zeolite-containing Co–Al₂O₃/SiO₂/ZSM-5/Al₂O₃ catalyst in flow and recycle flow operation modes at a temperature of 250°C, a pressure of 2.0 MPa, a gas hourly space velocity (GHSV) of 1000 h⁻¹, an H₂/CO ratio of 1.70 in the feed gas, and recycle ratios of 4, 8, and 16 has been studied. It has been found that the process parameters (selectivity and productivity with respect to C₅₊ hydrocarbons) pass through a maximum at a recycle ratio of 8. The use of gas recycling, unlike the flow synthesis mode, makes it possible to control the product composition. An increase in the recycle ratio in a range of 4–16 leads to an increase in the content of synthesized C₅–C₂₀ alkenes from 53.9 to 65.7 wt %. The use of a zeolite-containing catalyst, compared with a Co–Al₂O₃/SiO₂ catalyst, intensifies the formation of C₈–C₁₂ alkenes by 3.3 times: their content increases from 13.5 to 44.2 wt % at identical recycle ratios, pressures, and an H₂/CO ratio of 1.70 in the feed gas. It has been found that with an increase in the recycle ratio, the deactivation rate of the zeolite-containing catalyst decreases; this fact can be attributed to a decrease in the partial pressure of water in the reaction volume.