N-CNT is a promising material for various applications, including catalysis, electronics, etc., whose widespread use is limited by the significant cost of production. CVD-synthesis using a propane–ammonia mixture is one of the cost-effective processes for obtaining carbon nanomaterials. In this work, the CVD-synthesis of N-CNT was conducted in a traditional bed reactor using catalyst: (Al_0,4Fe_0,48Co_0,12)₂O₃ + 3% MoO₃. The synthesized material was characterized by XPS spectroscopy, ASAP, TEM and SEM-microscopy. It is shown that the carbon material contains various morphological structures, including multiwalled carbon nanotubes (MWCNT), bamboo-like structures, spherical and irregular sections. The content of structures (bamboo-like and spherical structure) caused by the incorporation of nitrogen into the carbon nanotube structure depends on the synthesis temperature and the ammonia content in the reaction mixture. The optimal conditions for CVD-synthesis were determined: the temperature range (650–700 °C), the composition (C₃H₈/NH₃ = 50/50%) and flow rate of the ammonia-propane mixture (200 mL/min).

This article presents an analysis of kinetic studies of dry methane reforming (DRM) in a reactor with a membrane catalyst (RMC) in the modes of a contactor with “diffusion” and “forced” mass transfer. Comparison of the specific rate constants of the methane dissociation reaction in membrane and traditional reactors confirmed the phenomenon of intensification of dry methane reforming in a membrane catalyst (MC). It has been experimentally established that during DRM, a temperature gradient arises in the channels of the pore structure of the membrane catalyst, characterized by a decrease in temperature towards the inner volume of the MC, and initiates the phenomenon of thermal slip. The features of this phenomenon are highlighted and must be considered in the analysis of kinetic data. The main provisions of the hypothesis explaining the effect of intensification by the occurrence of thermal slip in the channels of the pore structure of the MC are formulated. The proposed hypothesis, based on thermal slip, explains the difference in rate constants of traditional and membrane catalysts, and substantiates the phenomenological scheme of DRM stages in a reactor with a membrane catalyst.

The article presents an analysis of the kinetic data on dry reforming of methane (DRM) in reactors with traditional (TC) and membrane catalysts (MC). The kinetic experiment in reactors with the TC and MC is performed in the temperature range of 820–900°С at CH₄ : CO₂ = 1 : 1. The experiment reveals intensification of the reaction of methane cracking; its rate constant increases by an order of magnitude. This difference in the DRM data obtained for the studied catalysts is explained by the fact in the case of the MC mass transfer is intensified due to the thermal slip phenomenon. A mathematical description corresponding to the kinetic scheme of the DRM process is proposed, and the rate constants of direct and reverse reactions in both reactors are determined. The DRM process carried out on the TC yields water vapor, while in the case of the MC syngas is produced. On the TC the DRM process is accompanied by the accumulation of carbon deposits (CDs), while on the MC this accumulation is absent. On the TC the DRM process is characterized by three main reactions (methane cracking, gasification of CDs with carbon dioxide and/or water vapor, and reverse water gas shift) which are assumed to be reversible under the experimental conditions. It is found that the gasification of CDs on the TC occurs in the reverse reaction of methane cracking; on the MC, in the reactions of CDs gasification with water vapor (mostly) and carbon dioxide. In the case of the MC, the process is characterized by the irreversible reactions of methane cracking and CDs gasification with water vapor and carbon dioxide. The reverse water gas shift reaction on the MC remains reversible, and its rate constants of direct and reverse reactions are an order of magnitude lower than similar rate constants on the TC.

The article presents an analysis of the results of a kinetic study of dry reforming of methane (UCM) in reactors with traditional (TC) and membrane catalysts (MC). The kinetic experiment in reactors with MC and TC was performed in the temperature range of 820–900°C and the ratio CH4 : CO2 = 1 : 1. In the experiment, an intensification of the process of the methane cracking reaction was established, the rate constant of which increases by an order of magnitude. Such a difference in the results of the DRM on the studied catalysts are due to the intensification of mass transfer on the MC, which is based on the phenomenon of thermal slip. A mathematical description corresponding to the kinetic scheme of DRM process is proposed, and the rates constants of direct and reverse reactions in both reactors are found. In the DRM process, water gas is formed on the TC, and synthesis gas is formed on the MC. At TC, the DRM process is accompanied by the accumulation of carbon deposits (CD), and at MC this accumulation is absent. The DRM process on both catalysts is characterized by three main reactions (methane cracking, gasification of the CD with carbon dioxide and/or water vapor and the reverse water gas shift), which were assumed to be reversible under experimental conditions. It turned out that on TC the gasification of the CD occurs in the reverse reaction of methane cracking, and on the MC—in the reactions of gasification by water vapor (mainly) and carbon dioxide. The process on the MC is characterized by irreversible reactions of methane cracking, gasification of the CD with water vapor and carbon dioxide. The reverse water gas shift reaction on the MC remains reversible, and its rate constants of the direct and inverse reactions turned out to be an order of magnitude lower than similar constants on the TC.

Oxidative dry reforming of methane (ODRM) in a membrane reactor can become the basis for creating an energy-efficient process for converting greenhouse gases into a sought-after chemical raw material for gas chemistry. The process was carried out in a distribution mode in a reactor with a membrane porous catalyst (MPC) at a temperature of 850 °C. The reagents CH₄ and CO₂ were supplied to the MPC through a volume of retentate, and O₂ mixed with N₂ through a volume of permeate. The mixture of reaction products was removed from the shell side. In the experiment, the effect of the O₂/CO₂ ratio on the conversion of CH₄, CO₂ and O₂, as well as on the thermal effect of the process, was established. When oxygen enters the reactor during dry reforming of methane (DRM), the temperature inversion in the volumes of retentate and permeate occurs, as well as a decrease in electricity consumption in the resistor furnace. The observed effects of the ODRM process in MPC were interpreted using the hypothesis of active mass transfer occurring in pore channels. It is assumed that part of the carbon deposits in MPC will be gasified by oxygen.