Dmitry Andreev

Recently, due to the depletion of hydrocarbon fuel reserves against the background of high rates of decline in their reserves, considerable attention has been paid to the development of effective methods for synthesizing biofuels and biodiesel fuels, including from renewable sources of raw materials. However, a high cost price of biodiesel production requires the development of new technological approaches. Therefore, the direction of using microchannel (microfluidic) technologies for the synthesis of biodiesel fuel has begun to actively develop in chemistry and chemical technology. The use of microchannel (MC) reactors facilitates the intensification and safety of chemical processes, resulting in economic and environmental benefits for the chemical industry. The miniature dimensions of MC reactors allow for savings in materials during their manufacture, as well as resources during operation. Increased heat and mass transfer values in MC reactors contribute to a significant increase in the productivity of installations, exceeding the productivity of classical reactors in industry by 1–2 orders of magnitude. This review analyzes literature data for 2020–2024 devoted to the application of microchannel technologies for the synthesis of biodiesel fuel. Particular attention is paid to the advantages and disadvantages of MC reactors, as well as the main trends in their development.

New Cd–Zn/TiO₂ and Cu–Zn/TiO₂ catalysts based on nanodispersed titanium(IV) oxide are synthesized and characterized via X-ray diffraction analysis, low-temperature nitrogen adsorption, and temperature-programmed reduction with hydrogen. The activity of the synthesized catalysts in methanol steam reforming is studied under conditions of a microchannel reactor. It is shown that the highest activity is exhibited by Cd-containing catalysts, which are also characterized by the lowest carbon monoxide selectivity. The catalytic and physicochemical properties of the studied catalysts are compared. A correlation between the catalyst activity and the ability of Ti⁴⁺ cations in a TiO₂ support to undergo partial hydrogen reduction to Ti³⁺ is shown. It is speculated that the reducibility of titanium cations depends on the semiconductor properties of the oxides in the catalyst.

The possibility of using microchannel flow reactors to obtain the kinetic and technological parameters of the synthesis of 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid is demonstrated for the reaction of 1-methylimidazole (MIm) with 1-chlorobutane with no solvents. BMIMCl is produced with high selectivity and specific output in a microchannel flow reactor at temperatures of 120–180°C a contact time of 2–45 min, and a pressure of 20 bar. A positive result is obtained, due to the laminar profile of the flow and a uniform distribution of the reagents concentration over the microchannel cross section. Studying the kinetics of the process in a microchannel flow reactor reveals a shift of the reaction to the mode of diffusive inhibition at temperatures above 150°C. The kinetic data obtained for BMIMCl synthesis are used to develop ways of producing 1-ethyl-3-methylimidazolium and 1-hexyl-3-methylimidazolium chlorides (EMIMCl and HMIMCl, respectively) under the conditions of a microchannel flow reactor. The approach proposed in this work is of interest in developing flow and periodic facilities for the low-tonnage production of dialkylimidazolium, ammonium, and pyridinium salts via quaternization of the corresponding alkyl chlorides and nitrogen-containing bases.

Experimental studies of ammonia oxyethylation in a flow microchannel reactor are performed in broad ranges of temperatures (70–180°C) and residence times (0.47–3.3 min). The main products of...

This paper reports the results of a study of a water–gas shift reaction over nickel–ceria catalysts with different metal loading. Within this study, the overall CO conversion and observed kinetic behavior were investigated over the temperature range of 250–550 °C in different reactor configurations (fixed-bed and microchannel reactors). The quasi-steady state kinetics of the CO water–gas shift reaction was studied for fractions of Ni-containing cerium oxide catalysts in fixed-bed experiments at lab-scale level using a very dilute gas (1% CO + 1.8% H₂O in Не). A set of experiments with a microchannel reactor was performed using the feed composition (CO:H₂O:H₂:N₂ = 1:2:2:2), representing a product gas from methane partial oxidation. The results were interpreted using computational models. The kinetic parameters were determined by regression analysis, while mechanistic aspects were considered only briefly. Simulation of the WGS reaction in the microreactor was also carried out by using the COMSOL Multiphysics program.

The activity of Co/ZnO and Rh/Al₂O₃ catalysts in ethanol steam reforming was studied in a traditional tubular reactor with a fixed catalyst bed and in a microchannel reactor. At temperatures of 600 and 700°C, the Rh/Al₂O₃ catalyst was much more active and stable than Co/ZnO. A comparison between the reactors of two types showed that the ethanol steam reforming occurred more efficiently in the microchannel reactor because of intense heat and mass exchange. The specific hydrogen production per unit weight of catalyst in the microchannel reactor was almost twice as high as that in the traditional reactor.

The Cu_18.5Ce _x Al_{81.5 − x} (where x = 2, 7.4, and 14) oxide catalysts were synthesized by coprecipitation and tested in the methanol steam reforming reaction in an integral flow reactor at 270°C. It was found that the activity of the catalysts increased with the calcination temperature and catalysts with intermediate cerium contents exhibited the highest activity; these catalysts exhibited the greatest values of S _BET and S _Cu. The phase analysis demonstrated that copper in these samples occurred almost entirely as a CuO-CeO₂ solid solution. The concentration of carbon monoxide at the reactor outlet decreased with the calcination temperature. For the most active sample with a cerium content of 7.4% calcinated at 700°C, the concentration of CO reached a minimum of no higher than 0.3%.

Methanol steam reforming in microreactors is considered, and the effects of the microreactor geometry (cylindrical and rectangular) and microchannel plate (MCP) design on the hydrogen capacity of the microreactor is analyzed. The MCPs were made from aluminum foil, stainless steel, and foamed nickel by laser engraving, electrochemical etching, and pressing. The amount of catalyst powder (CuO/ZnO = 40: 60 mol/mol) fixed on one MCP was 0.04–2.5 g. The specific hydrogen capacity (U _w) of the cylindrical microreactor is more than 3 times as high as the U _w of the rectangular microreactor and is 6 times as high as the U _w of a conventional fixed-bed catalytic reactor. This gain in hydrogen capacity is due to the more efficient use of the catalyst in the microreactors. The MCP design, which determines the residence time of the reactants in the microreactor, also has a significant effect on the capacity of the microreactor.