Conversion Of Hydrocarbon Gases Research Articles

Компиляция данных по оптимизации работы трубчатых печей

A great number of processing hydrocarbon raw material units operated at enterprises have heat exchangers of different designs. A significant share among them comes to the special heat exchangers that use the heat of exhaust gases when burning liquid and gaseous fuels – tubular furnaces. Depending on the specifics and type of fuel used, the furnaces differ both in design and in operational parameters. At AT units, AVT units, and gasoline secondary distillation units, HFC furnaces are used to heat hydrocarbon media and are characterized by heating temperatures from 300C° to 500°C. In the units of technological processes of pyrolysis, conversion of hydrocarbon gases, etc., simultaneously with heating and/or overheating of the raw materials, furnaces are used as reactors. The effective use of such furnaces is possible only if there are used engineering methods predicting changes in the technological flow, created on the basis of reliable analytical and experimental materials. The available data is insufficient to develop measures 
 to improve the efficiency and reliability of these units. There are discussed the results of analytical studying the optimizing the operation of tubular furnaces, identified the main disadvantages during their operation, determined methods for assessing the wear of the elements of the apparatus depending on the technological modes (temperature, pressure, medium) and the material of execution in the process of technical diagnostics of equipment to ensure industrial safety. The issues of the influence of design features and of organizing the combustion process of nozzles on the quality indicators of tubular furnaces are considered. The main directions of increasing the energy efficiency of radiant and convection chambers of tubular furnaces are defined.

Evaluation of the effect of various catalysts on the yield of hydrogen and nanofiber carbon during pyrolysis of hydrocarbon gases

This article provides a literary review of pyrolysis catalysts for the production of alternative energy fuel in the form of hydrogen, as well as an equally useful product of nanofiber carbon. A theoretical analysis of the effectiveness of the use of catalysts based on the yield of a useful product was carried out. It was found that the most promising catalysts for industrial use are high-percentage nickel and copper-nickel catalysts. Most effective catalyst in the process of obtaining hydrogen by the method of catalytic decomposition of hydrocarbon gases is the 40Ni/SiO2 catalyst, the yield of hydrogen when used is 80.7 mol/gcat, and the highest yield of nanofiber carbon 449 g/gcat makes it possible to obtain a bimetallic catalyst (75Ni-15Cu)/Al2O3. The methods of preparation of applied catalysts are also considered, the advantages and disadvantages of each are described. Keywords: bimetallic Fe-Co catalysts; bimetallic Ni-Cu catalysts; pyrolysis catalysts; conversion of hydrocarbon gases; nanofiber carbon; nickel catalyst; hydrogen production.

Oxidative plasma chemical transformations of C3-C4 alkanes

The results of oxidation of a propane-butane mixture (liquefied petroleum gas) with oxygen in a barrier discharge plasma in the presence of liquid octane are presented. The transformation of the initial mixture results in the formation of predominantly hydroxyl and carbonyl compounds of the initial gaseous C3-C4 hydrocarbons. The mechanism of hydrocarbon oxidation is similar to that of transformation of liquid hydrocarbons in the barrier discharge plasma. An increase in the initial concentration of the propane-butane mixture in the gas phase results in a decrease in the conversion of gaseous hydrocarbons and octane in one pass through the reactor. Calculations performed using the Bolsig+ program show that a reduction in conversion of gaseous hydrocarbons is due to a decrease in the rate constant of the oxygen dissociation reaction resulted from a decrease in the average electron energy from 4.1 to 3.4 eV. A mathematical expression is proposed, which allows predicting the direction of the plasma-chemical reaction.

Jets in scientific research and technological applications

A brief review of the work carried out at the Institute of Thermophysics of the SB RAS on the use of supersonic jets in scientific research to obtain relaxation process constants is presented, such as, effective cross sections for quenching of electronic states, atoms, molecules and ions. Also a review of the work directed to the use of jets and electron beams in various plasma-chemical technologies is given, namely, deposition of functional layers of thin-film silicon solar cells and conversion of hydrocarbon gases into useful products.

Conversion of hydrocarbon gases in dielectric barrier discharge in the presence of water

The conversion of C1–C4 hydrocarbons into gaseous and liquid products in a dielectric barrier discharge plasma in the presence of water has been studied. The formation of a deposit on the electrode surface is prevented by introducing water in the liquid state into a gaseous hydrocarbon stream, a finding that has been confirmed by IR spectroscopic study of the electrode surface. Hydrogen and C2+ hydrocarbons have been detected among the gaseous products of conversion, the liquid products being represented by C6–C10+ alkanes. The total liquid products have amounted to 13.4, 26.0, or 36.6% for the methane, propane, or n-butane conversion, respectively. A 10% propane or butane admixture to methane increases the yield of the liquid products to make 22.0 and 31.7% for the methane–propane and the methane–butane mixture, respectively.

Mechanically Activated Chemical Conversion of Gaseous Hydrocarbons

Propane-butane gaseous mixtures were subjected to mechanical treatment in centrifugal ball mill in the absence or presence of some mineral particles. It was found that the composition of gas mixture was changed significantly depending on duration of the mechanical coercion and solid or porous nature of mineral additives. The mechanical treatment of light hydrocarbons in the presence of quartz particles at the temperatures not exceeding 100 °C resulted at long last in complete conversion of initial organic compounds to methane, hydrogen and small amounts of carbon. The same alterations of gas composition were lesser profound when the mechanical treatment was carried out in the absence of minerals or in the presence of porous silica gel or aluminum oxide. It have been shown that direct transformation of mechanic energy to intramolecular energy of hydrocarbons is more responsible for their destruction during the process considered rather than catalytic properties of the minerals. The removal of heavier hydrocarbons from natural or casing-head petroleum gas by means of MA treatment permits to facilitate further gas transportation and to improve essentially its heat-physical properties, namely, to decrease gas average molecular mass and specific gravity and to increase its caloricity and Wobbe number' values.

Oxidative conversion of hydrocarbon gases in the surface combustion mode

An increase in the natural gas fraction produced from low-debit unconventional resources requires new small-scale technologies for its transportation, conversion to chemicals, and ecologically safe use in power production. A technology of flameless combustion and partial oxidation of natural gas in combustors or converters with permeable volumetric matrix is proposed as an efficient method for the solution of these problems.

Syngas and hydrogen production in a volumetric radiant burner

The production of syngas is the most energy demanding and metal consuming stage in the conversion of gaseous hydrocarbons (GH's) into value-added products. Its complexity restrains many practical applications of chemical processing of GH's, especially for low scale of operation. The paper describes new compact and highly productive generator of syngas and hydrogen based on the combustion of GH's in volumetric permeable matrixes with locked IR radiation that can serve as a solution of this problem. It is shown that such simple devices can provide a highly efficient methane conversion into syngas and thus facilitate the utilization of low-capacity sources of GH's for economically feasible low scale syngas and hydrogen production from various local hydrocarbon sources.