GENERAL PROBLEMS OF CATALYSIS
Market analysis of rare earth metals (REM) and REM-catalyst is given. The base data about the field of REM in Russia and in the world are represented. Analysis of the use of REM with a focus on the production of magnets and catalysts is available. Data about an applications of REM-catalysts: neutralization of vehicle exhaust, catalytic cracking, hydrogenation, dehydrogenation, hydration, dehydration, steam, carbon dioxide and oxidative conversion of methane, waste water treatment, etc. are given. There is conclusion that the development of REM-catalysts may provide a breakthrough in the field of energy-efficient low-temperature catalytic processes.
The increasing the stability of the MFI type zeolite catalysts is actual for creating of high active catalysts for methanol conversion to C2–C4 hydrocarbon gases or hydrocarbons to aromatics – an important industrial processes. Three new approach to improve the stability of zeolite catalysts are proposed in the work: the selective dealumination on the outer surface of the MFI zeolite crystals; the structure-selective ion exchange on the external surface of the crystals, the use of isothermal (tubular) reactor. The influence of conditions of selective dealumination and structurally selective ion exchange on the molar ratio SiO2/Al2O3 of the zeolite and time between regeneration running in the conversion of methanol into hydrocarbons is studied. It is found that the selective dealumination of external surface leads to an increase of between regeneration running up to 3–5 times. Structure-selective ion exchange on the outer surface of the zeolite crystals can increase the time of running in 2–4 times, reduce the temperature and duration of recovery due to changes in the properties of the deposited coke. Application of the tubular reactor allows to facilitate the regeneration process compared with an adiabatic reactor by the formation of less condensed coke.
The conditions and possibility of carrying out the process of extrusion iron-molybdenum catalyst for catalytic oxidation of methanol to formaldehyde were investigated to produce energy-saving ribbed sizes catalyst. A comparative analysis was provided on the impact of molding method on quality of energysaving ribbed sizes catalyst – ribbed granules and tubes. It is shown that instead of extrusion the increase performance of the catalyst is provided: total porosity up on 30 %, surface area on 20 % of the pore volume of the optimum size of 3 times and the mechanical strength of the tubes (rings) on 4 % edged granules on 20 %.
CATALYSIS IN CHEMICAL AND PETROCHEMICAL INDUSTRY
Hybrid metal-zeolite catalysts are prepared and modified with transition metals (Pd, Fe, Co, Ni) for the direct synthesis of hydrocarbons of С5–С18 of CO and H2. State of the active catalyst component (dispersion, surface area and the recovery of Co) was studied by temperature-programmed reduction and oxygen adsorption. The catalytic performance of the samples are identified. Tests were carried out in a continuous tubular reactor with a diameter of 1,3 cm at 2 MPa and a temperature from 210 to 250 °С on the catalyst fraction 0,1–0,2 mm, weigh of samples 2,5 cm3. The activity of the samples increases in the Co Fe < Ni. In order to optimize the composition of the catalyst system the catalyst characteristics with a variable nickel content of 2, 4, 6 and 8 wt.% were studied. The maximum yield of liquid hydrocarbons from CO and H2 (120 g/m3 synthesis gas) was obtained by using a catalyst containing 4 wt.% Ni. The Tests on the granules (1,5–3,5 mm) of the catalyst in the reactor with increased load (50 cm3) were held that is showed the possibility of its use in a pilot plant.
INDUSTRY ENGINEERING PROBLEMS. OPERATION AND PRODUCTION
The possibility of regeneration of the catalysts for dehydrogenation С9–С14 paraffins was investigated. The catalysts were prepared on the basis of the active metal (platinum) and promoters supported on Al2O3 or (magnesium) aluminosilicates. The factual data of catalysts runs is used in industrial environments. The stages of coke burning and oxychlorination were investigated using thermogravimetric analysis and a method of mathematical modeling. It is shown that in the way of correct mode of regeneration the lifetime of the catalyst can be extended by 25–30 %. The way of reconstruction of dehydrogenation unit was proposed to allow the regeneration including burning of coke and oxychlorination.
The results of the parametric analysis of the oxidation of methanol to formaldehyde based kinetic model on iron-molybdenum oxide catalyst and a two-dimensional mathematical model of the tubular reactor are presented in the article. Results of the kinetic experiments of industrial granules Fe-Mo catalyst are shown and compared with the industrial data. Features of control of the methanol to formaldehyde oxidation process in the tubular reactor when the plant productivity is changing in view of technological limitations are investigated theoretically. The influence of parameters on the temperature and concentration conditions in the reactor at different ratios loading catalyst and inert material is studied.
DOMESTIC CATALYST
Catalysts deep oxidation of CO and organic compounds are investigated by set of physical and chemical methods such as BET, XRD, XPS, HREM. These were the industrial catalysts (SCHKZ-1, IC-12-73) and samples of the catalysts prepared by the members of the writing team in Boreskov Institute of Catalysis (KGOS20, KGO-O30-oxide aluminum-copper-magnesium-chrome). Phase catalyst composition and the distribution of active components in a catalyst granules are determined. Testing of the catalysts in the CO oxidation in a flow reactor or in a pulsed mode are performed. It’s found that in both cases, the activity of the catalysts decreases in the order: SCHKZ-1 > KGO-20 ≈ ≈ KGO-O30 > IC-12-73. Experimental batch of copper oxide-luminum-magnesium-chromium (CuO-MgO-Cr2O3/Al2O3) catalyst based on alumina (company Sasol Germany GmbH) was prepared and tested in the combustion of solid fuels in a fluidized bed. The high activity of the catalyst in the VOC, CO, and coke oxidation as well as high abrasion resistance. The CO concentration
at the out of the reactor during the catalyst test is according to sanitary requirements.
Aniline is one of the most important products of heavy organic synthesis. Its importance to the national economy is emphasized in the title of one of the branches of chemical industry – aniline-dye industry. Until the late 50’s of the twentieth century, almost last 100 years aniline was produced in the world is mainly by method Béchamp. It is a liquid phase reduction of nitrobenzene iron turnings in an acidic medium. At the turn of the 50’s and 60’s of the last century in the production of aniline, a transition to a new progressive way was made – to catalytic vapor-phase reduction of nitrobenzene by hydrogen. Abroad and in USSR this method was mastered in industry almost simultaneously and its development occurred independently. In the Soviet Union, the creator of this method was the Soviet chemist I.M. Tsapko who developed the catalyst B-3. The first workshop production of aniline with capacity 18 thousand tons of product per year was commissioned in 1958 at the Bereznikovskiy aniline-colorful plant on this catalyst. At the load 897 kg/h of nitrobenzene and 2090 nm3/h of hydrogen for one contact system (found in the shop four contact systems) are obtained 668 kg / h of aniline. The yield of aniline at contacting step was 98,5 mol.%. Mode of operation of the catalyst: preparation of aniline – 125 hours, the catalyst regeneration – 15 hours This method provides a reduction of product cost at 15 %. In the present article the plant scheme and operating conditions of the catalyst in the vapor phase production of aniline.
CHRONICLE
ISSN 2413-6476 (Online)