Gas-dynamic Resistance Research Articles

Optimization of the intake system for the Setra NS 913 bus

Abstract The paper presents the implementation on buses of a dynamic air transfer system (SDTA) brand Air by Corneliu. That system is the subject of a patent entitled Dynamic Air Transfer Device RO 200900028. At the initiative of the Alba Iulia public Transport society, with a fleet of about 100 buses, we started a study on the efficiency of air intake in the internal combustion engine by implementing an SDTA. Since the air filter location on this bus model, Setra NS 913, is behind the rear axle wheels, the filter is exposed to dust, water and other particles thrown by the drive wheels, which leads to premature clogging and blockage of the filtration area, in the context in which the bus runs mainly on asphalt-free roads. The gas-dynamic resistance (filter permissiveness) would increase considerably, resulting in a severe reduction in the degree of filling of the engine cylinders. In order to eliminate the disadvantages mentioned above, respectively to increase the life of the air filter with implications on the performance of the engine, we have designed a dynamic system consisting of the following components: the air collector, located on the top of the bus; the grid housing, located on the suction grid; tubing, connecting element between the air collector and the grid housing. In order to realize the 3D model of SDTA, the specialized software VISI - CAD / CAM was used.

Analysis of the influence of uneveneity of the sintering process of the barch on the operation of the sintering machine

Literature data on the unevenness of temperature and composition of the gas leaving the sintering bed across the width and length of it and their influence on the productivity of sinter machines are considered. An analysis of the technologies reasons for the unevenness of the sintering process was carried out. It is shown that the reasons for the width of the pallets include the distribution of the mix bed in the loading bin, air leaks into the ignition hearth, the wall effect at the side plates of the pallets, the shape and angle of inclination of the sides relative to the grates. Along the length of the sinter machine, the unevenness of gas flow and composition is due to a decrease in the gas-dynamic re-sistance of the bed during the sintering process, segregation of the mix and fuel along the height of the bed, completion of bed drying and gaps between pallets. Using an adapted mathematical model of the sintering process, a comparison was made of the parameters of the basic (non-uniform) and calculated uniform operating modes of the AKM-312 sinter machine of the Steel Plant NLMK. I It has been established that with the vertical installation of the pallet sides accepted in the calculations that an increased gas flow rate at the periphery of the bed is accompanied by an increase in gas temperature with a corresponding decrease in the suction before exhausters. It was found that during the transition from the base to the uniform mode of operation of the sinter machine, the gas temperature in front of the exhausters decreased from 99.6 to 85.1 °C, the suction increased from 13.54 to 14.26 kPa, and in the collecting collector – by 1.15 kPa. The productivity of the sinter machine increased by 4.1%. When installing pallet sides vertically, the effectiveness of increasing the height of the layer on its periphery instead of compacting it and constructive solutions has been justified. Its increase provided an additional productivity of the sinter machine by 1.8%, a total of 5.9%. It has been shown that due to the simultaneous increase in gas temperature over the entire width of the bed in the final period of the sintering process, with a uniform operating mode of the sinter machine, the maximum gas temperature at the end of the process increases with a lower one – in front of the exhausters. From the point of view of the capabilities of exhausters in terms of the created suction, the accepted representation of their gas-dynamic characteristics at a temperature of 150 °C, which is possible only with a high level of unevenness of the sintering process, is not reasoned

Design development and industrial testing grate of sinter machines of SP-5 PJSC “MMK”

Review of research works on improving the design of the grate bars of sinter machines of SP in the CIS has been made. It is shown that the grate of the AF-5 sinter machines does not comply with the technological and design requirements, which leads to its intense thermal and abrasive wear, deformation, falling out of the sinter carts and increased consumption of grates, as well as thermal protection overlays of the grate beams under them. On the one hand, a bed of sinter with a rational fractional composition (10‒20 mm) and a height (50 mm) of AF-5 sinter machines are shown to have a positive effect on the work of the grate, and on the opposite side, rippers of the mix bed of the loading unit and frequent short-term stops of the sinter-machines. An experimental design of a massive rationally shaped grate was developed and successfully tested on three pallets during the year. Deformation, “herringbone” and loss of grate, as well as thermal insulation pads under them were absent. Despite the fact that modern sinter machines are equipped with clamping devices of pallets, the influence of gaps between them on the speed of movement of the high temperature front in the bed has been revealed. The accelerated abrasive and thermal wear of the upper hooks of the grate located on the extreme under-grate beams has been established. The negative effect of the blades of the mix ripper and the areas of the bed below them, in which the sintering process is completed earlier than in the adjacent areas of the bed, is revealed. As a result, the residence time of the grates in high-temperature zones increases, and its thermal and abrasive wear increases. In the process of testing, it was revealed also the need to reduce the length of the cheeks of the upper hooks of the grate bars to increase the free section of the grate from 7.8 to 13.0%, which will reduce its gas-dynamic resistance. The final version provides for a decrease in the height of the grates from 60 to 50 mm and, accordingly, its weight ‒ from 10.2 to 8.7 kg, taking into account the gradual, rather than simultaneous replacement of existing grates with massive ones, and sufficient height for them a protective layer equal to 30 mm instead of 50 mm for the existing ones. Reducing the height of the protective layer from 50 to 30 mm will increase the output of sinter by 20 t/h. According to the results of the experiments, the specific consumption of massive grates is predicted to be 30 g/t of sinter at the current consumption of 67 g/t. The commercial supply of sintering pallets with new grate bars and the replacement of existing ones have begun.

Influence of valve effect on energy efficiency of layer gasdynamic systems

The direction of gas movement and the properties of the granular layer, which must be taken into account in the Darcy-Weisbach formula, have a significant effect on the energy efficiency of gas-dynamic processes in layered systems. The complex form of the regularity of the coefficient of resistance from the content of fine fractions in the layer is justified by the wavy shape of the channels in which the fine fractions are located. However, this phenomenon can be justified by the forced migration of small particles inside the cavities of the layer under the influence of mobile gases. The influence of the mobility of particles during air blowing of separated and mixed granular layers on the coefficient of gas-dynamic resistance is investigated. A smooth decrease in the value of the coefficient with an increase in the air flow rate before the transition of the layer to the fluidization mode was observed for monofraction layers. Fractures, caused by the formation of a low-permeability area due to the placement of small fractions in narrow places between large ones, have been identified for the separated layers. The presence of such a fracture depends on the ratio of particle sizes and their roughness. The increase in pressure under the bed allows the fines to gradually move upward through the voids between the larger fractions. A layer of small balls formed on top and the pressure loss in the entire steel layer is about twice as high as for the separated layer. This is due to the fact that the small balls completely fill the voids between the large pellets and the total height of the column of balls in the channels of the layer has approximately doubled in relation to the initial filling height. In addition, the tortuosity of the channels between large pellets, through which air passes, increases, which contributes to an increase in the gas-dynamic resistance to the layer. An abrupt transition to a "fluidized" bed is observed for a monofractional charge of small balls at a critical gas pressure drop, pressure pulsations occur ±100 Pа and consumption ±0,365·10–3 m3/s. A spontaneous sharp drop in the drop occurs after the formation of geyser channels. The rigid structure of the layer, characteristic of the agglomeration process, ensures uniform movement of gases in the layer, but the valve effect occurs when the content of fine fractions in the layer is more than 3.1 % and increases the energy consumption for the movement of gases in the layer by 30 %. The placement of two or more particles in such cavities between large and retained in them due to friction forces occurs in this case. Elimination of the low-permeability barrier will increase the height of the dormant layer from 400 to 550–600 mm and reduce the consumption of solid fuel of the charge by 10–15 % due to its redistribution along the height.

О возможности использования керамических высокопористых блочно-ячеистых материалов в качестве контактных сорбционно-фильтрующих элементов

The paper considers the structural and physical characteristics of carriers based on ceramic highly porous block materials of a cellular structure, which provide the sorption-filtering properties of contact elements. Methods for determining the external specific volumetric surface, gas-dynamic resistance and gas permeability are described. Their interrelation and optimal combination with the operational characteristics of sorbent filters in the processes of capturing volatile compounds of iodine and cesium in gas streams is shown. The results obtained can be used to synthesize contact elements of a new class and create on their basis highly efficient gas cleaning systems operating at high temperatures and corrosive environments.

УСТРОЙСТВО ДЛЯ ОЧИСТКИ ОТРАБОТАВШИХ ГАЗОВ ДИЗЕЛЬНЫХ ДВИГАТЕЛЕЙ ВНУТРЕННЕГО СГОРАНИЯ

To ensure high quality and productive work of employ-ees, it is necessary to achieve the target parameters of the microclimate and to exclude harmful and toxic substances in the atmosphere of the working area of agricultural prem-ises of a closed volume and air exchange. The main rea-son for the distortion of the air-gas regime of the room is the use of agricultural machines in closed industrial prem-ises (warehouses, storage facilities, livestock facilities, etc.). As a result, there is a decrease in the quality of prod-ucts and working conditions at agricultural enterprises, as well as a reduction in the operational life of structures. To-day, in agricultural machinery, diesel engines are most often used as power units which, unlike gasoline engines are more economical, and also reduce the harmful impact on the environment. But, despite this, the operation of die-sel engines still causes the accumulation of harmful com-ponents in the atmosphere of the room which negatively affects the health of the staff. The analysis of the designs of devices for exhaust gas purificationof internal combus-tion engines revealed the problems that affect the efficien-cy of the purification. The most significant problems are as following: large weight and dimensions, reduced efficiency of the neutralizers when the engine is running at modes close to the nominal ones, and large gas-dynamic re-sistance. To solve these problems, the design of a device for exhaust gas purificationin diesel engines was devel-oped. The use of this utility model will increase the efficien-cy of the device for exhaust gas purification. It will improve the environmental performance of the diesel engine reduc-ing emissions of harmful substances and soot into the at-mosphere.

Calculated determination of the flow coefficient through the intake system of the internal combustion engine

Taking into account the complexity and duration of creating the optimal shape of the flow part of the intake system, it is advisable to use mathematical models in its design and modernization. This not only reduces the cost and speeds up the creation of an optimal air path, but also provides conditions for automating the design process. The calculated determination of the flow coefficient using modern methods allows you to significantly reduce the amount of experimental research and solve the main problems by choosing the optimal combination of structural elements of the intake channels at the design and finishing stage of the engine. A method is proposed for calculating the flow rate through the intake system of an internal combustion engine (ICE) depending on the design features of the intake system elements: the flow resistance coefficient, the average speed of the piston, the cross-section area of the cylinder, the average effective flow of the valve slot, the number of valves, the value of the valve lift, the diameter of the neck. The influence of total losses from gas dynamic resistance is estimated.

Design, scale-up, and operation of a Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl alloy wire mesh honeycomb catalytic module in diesel autothermal reforming

Catalytic autothermal reforming is considered as one of the most effective methods for production of hydrogen from heavy hydrocarbon fuels for solid oxide fuel cells (SOFC). Diesel is an attractive fuel because of its high energy density, widespread use and well – developed infrastructure. Catalysts supported on structured carriers (e.g. FeCrAl modules) provide controlled reaction conditions throughout the reactor volume that favorably compete, for example, with fixed bed reactors. The use of structured catalysts provides efficient heat and mass transfer, low gas dynamic resistance, and high catalyst performance that facilitates the reduction of catalyst quantity per unit volume of the reactor. The ability to perform the process under controlled optimum conditions leads to increased selectivity and minimizes undesirable side reactions, such as coke formation. In the present work, the active component Rh/Ce0.75Zr0.25O2-δ was supported on FeCrAl metal meshes using Al2O3 as a binding structural component. The obtained catalysts Rh/Ce0.75Zr0.25O2-δ-ƞ-Al2O3/FeCrAl were tested in laboratory and pilot scale reactors in n-hexadecane and diesel autothermal reaction conditions. Winter grade diesel used in the experiments contained up to 31% of aromatics. Operating conditions were found to provide a 100% conversion of n-hexadecane and diesel and stable catalyst activity for a long time-on-stream exposure. The catalysts provided equilibrium product distribution and a maximum syngas (CO + H2) productivity of 3 m3Lcat−1h−1 (STP) at the studied experimental conditions. The produced syngas can be supplied as a fuel for power generation units based on high-temperature solid oxide fuel cells.

Application of manganous limestone as a fluxing addition at pellets production

Usage of non-fluxed pellets in blast furnaces results in blocking of hearth coke filling, decreasing of blast furnaces productivity and increasing of coke rate. The wide range of plastic-viscous state and non-sufficient filterability of pellets slag portion through the coke filling are the main reasons of the consequences. Fluxed pellets have narrower interval of plastic-viscous state and better filterability of pellets slag portion through the coke filling. Their utilization enables to decrease the gas-dynamic resistance of blast furnace cohesion zone, to eliminate progressive hearth blocking, to intensify the hot metal production process and to increase its economic efficiency. In 70–80thof the previous century attempts were made to substitute the bentonite in burden at pellets production by hydrated lime and burnt lime, by marl, by nontronite clay, by red sludge and other additives, combining properties of the raw pellets strengthening and fluxing. But the methods listed were not implemented practically, in particular, because of difficulties in those two properties effective combining. Last years a new raw material appeared at the fluxes market – the manganous limestone. Manganese oxide, contained in it, decreases the sinter smelting temperature, calcium carbonate acts as a flux, while water and physical properties of the limestone improve the increase of the burden lump-forming capacity and sinter strength. The aim of the study was to check the manganous limestone influence on the production process and raw pellets strength, change of roasting parameters and strength of roasted pellets, as well as change of high-temperature properties of fluxed pellets made of Stojlensky GOK concentrates. The study were carried out in laboratory conditions by usage of Dash-Salakhlin bentonite and manganous limestone. The results of laboratory study of both raw and roasted pellets, obtained at utilization of manganous limestone as a fluxing additive to burden, showed, that their physical and mechanical properties are higher and metallurgical properties are higher, compared with non-fluxed pellets.

Study of transition processes of blast-furnace smelting by the mathematical model method

In work possibilities of the developed computer model system for forecasting of a thermal condition of a blast furnace (on change of the maintenance of silicon in pig-iron) in a mode of real time are considered. The basis of the model is the fundamental knowledge of the theory and practice of the modern blast-furnace process, the use of regularities in the processes of heat and mass transfer, gas dynamics, slag formation processes in modern blast furnace melting. When solving the dynamic problem, it is envisaged to use the analytical (obtained on the basis of fundamental knowledge), but the linearized model of the domain process, the principle of small deviations and the natural-mathematical approach. In the algorithm for solving problems in transient blast furnace processes, the calculation of the dynamics of the change in the heating of the bottom of a blast furnace (based on the silicon content in cast iron) was performed according to the additivity rule by summing the predicted silicon concentrations in cast iron when the loading parameters (ore load) and the control actions on the thermal load the state of the furnace from the bottom - the consumption of natural gas, the concentration of oxygen in the blast and the humidity of the blast. Examples of calculations of the transient processes of the gas-dynamic resistance of the batch layer, the thermal state, and the productivity of the blast furnace are shown in the context of the changes in the properties and composition of the iron-ore materials being loaded and the parameters of the combined blast are applied to the conditions of PJSC “Magnitogorsk Iron and Steel Works” (MMK).

Experimental Studies for Determining Gas Flow Rate Accidental Release on Linear Part of Pipeline

The method of determining the flow rate of gas in the gas-dynamic resistance of a medium gas stream with high linear speed was studied. The reduction of the density of the gas is a result of its expansion. Multiple calculations of gas losses were evaluated. Calculation is set by loss of gas depending on the area of the pipeline damage. A comparative analysis was done. In order to establish a functional empirical dependence of the flow rate on the whole on the parameters of the leakage process, a series of experiments was conducted on a test bench and their processing was carried out. In experiments conducted, the effect of pressure and temperature in the receiver was evaluated, the physical properties of the gas and the diameter of the hole were predetermined by the limits of the amount of the whole flow rate in critical conditions, as well as the critical regime of gas leakage.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ВЛИЯНИЯ СКОРОСТИ ГАЗА НА ТЕМПЕРАТУРНОЕ ПОЛЕ И ГИДРОДИНАМИЧЕСКИЕ ПОТЕРИ В ТЕПЛООБМЕННОЙ СЕКЦИИ КОМПАКТНОГО КОТЛА-УТИЛИЗАТОРА

The analysis of the numerical modeling results of gas dynamics in the ducts of the compact exhaust boiler is continued. Currently, there have been done three calculations for the same geometrical model; these calculations have different input speed values, as well as different methods of setting speed. It’s confirmed that in case of continuation of the original calculation with changed boundary condition (speed) in the inlet cross section the results coincide with results of calculation where originally set speed was the same. Thus, it becomes possible to perform several variants of calculations with the same geometry, but with different speed in one session (with minimum correction of initial data). So, the time of setting new temperature mode and the value of gas-dynamic resistance is reduced. Therefore, the time for preparing and carrying out the numerical experiment can be reduced. The influence of input speed on temperature field and hydrodynamic losses in exhaust boiler have been analyzed.

Features of Blast Furnace Transient Processes

The article considers principles of creating a logical dynamic model of the course of blast furnace smelting in a real time regime. It is based on actual operating behavior and its innovation, and data are provided for operation in this area that form the basis of this model or are used for its creation. Some blast furnace transient processes are studied. As a result of this, dependences are described for the effect of blast composition and parameters on molten product composition, and also the effect of charge composition on the gas dynamic resistance of a charge bed. Software is created demonstrating the relationships described with the aim of practical implementation of the model in question. Features of the blast furnace are provided for the transient processes considered, and practical recommendations are made for certain aspects of smelting.

Functioning efficiency of intermediate coolers of multistage steam-jet ejectors of steam turbines

Designs of various types of intermediate coolers of multistage ejectors are analyzed and thermal effectiveness and gas-dynamic resistance of coolers are estimated. Data on quantity of steam condensed from steam-air mixture in stage I of an ejector cooler was obtained on the basis of experimental results. It is established that the amount of steam condensed in the cooler constitutes 0.6–0.7 and is almost independent of operating steam pressure (and, consequently, of steam flow) and air amount in steam-air mixture. It is suggested to estimate the amount of condensed steam in a cooler of stage I based on comparison of computed and experimental characteristics of stage II. Computation taking this hypothesis for main types of mass produced multistage ejectors into account shows that 0.60–0.85 of steam amount should be condensed in stage I of the cooler. For ejectors with “pipe-in-pipe” type coolers (EPO-3-200) and helical coolers (EO-30), amount of condensed steam may reach 0.93–0.98. Estimation of gas-dynamic resistance of coolers shows that resistance from steam side in coolers with built-in and remote pipe bundle constitutes 100–300 Pa. Gas-dynamic resistance of “pipein- pipe” and helical type coolers is significantly higher (3–6 times) compared with pipe bundle. However, performance by “dry” (atmospheric) air is higher for ejectors with relatively high gas-dynamic resistance of coolers than those with low resistance at approximately equal operating flow values of ejectors.

Selecting the optimum method of heat transfer intensification to improve efficiency of thermoelectric generator

The relevance of applying the methods of energy recovery from exhaust gases is substantiated. The principle of operation of a thermoelectric generator is described, the variant of its design is proposed, and the efficiency of various design methods of heat exchange intensification is compared. Designs are compared with a baseline configuration without heat transfer intensifiers in terms of coefficients of gas dynamic resistance ξ/ξ0 and the ratio of dimensionless criteria Nu/Nu0. The results of comparative analysis have proved the applicability of the methods of heat exchange intensification in the design of thermoelectric generators of various vehicles.

Фрактальная геометрическая модель микроповерхности

The article is devoted to the construction of spatial
 model of microsuface module of copper alloy. A real surface has a
 characteristic roughness associated with the material creating technology,
 so knowing the geometric parameters of the surface microstructure
 is very important in studying properties such as microhardness,
 friction, aero- and gas-dynamic resistance and catalytic
 activity towards reactions of heterogeneous recombination of atoms
 in the active centers. To obtain qualitative data on the microsuface
 morphology, without imposing on the sample to stringent requirements,
 used a scanning tunneling microscope. Building a model
 creates a need to recreate the surface topology to study its geometrical
 properties, expressed through the fractal dimension. Such
 a simulation should help to study the interaction mechanism between
 molecules of a rarefied gas with the flying vehicle surface in the
 solution of gas dynamics problems associated with heat and mass
 transfer. In MathCAD the calculation of geometric characteristics
 of a spatial model from the standpoint of the fractal theory for the
 formation of geometrical shapes and GOST 2789-73 requirements
 to control their numerical parameters. The example of procedural
 (algorithmic) construction of geometrical model equivalent to the
 real is given. It is shown that with sufficient for practical applications
 accuracy the surface topology can be described by the fractal
 patterns that take into account irregularities, both at the micro and
 nanoscale. The proposed algorithm makes it possible to broadcast
 a method of creating a fractal structure at any detail level.
 Its positive and negative features based on the midpoint displacement
 modernized algorithm use are noted. The algorithm
 correctness for modeling the other materials surfaces geometry is
 shown.

Practical and Theoretical Research on the Sintering Process

The Novolipetsk Metallurgical Combine (NLMK) has collaborated with leading scientific-research institutes and scientists in the area of sinter production for decades. The combine’s sinter plant has been used to conduct many factory tests, and the results of those tests have helped refine and advance the theory of the main processes which take place during the sintering of iron-ore-bearing materials. The theoretical gains have in turn facilitated the introduction of a number of effective technologies. 1. Charging of the mix onto the sintering machine. During the 1980s and 1990s, several foreign sinter plants that sinter coarse-grained charges began to abandon the practice of two-layer charging that had been used on the sintering machines at the NLMK and the West-Siberian, Cherepovets, and Karaganda metallurgical combines. The change from twolayer charging brought about marked increases in sinter production, which led to study of the effect of different factors on the performance of the sintering machines at the NLMK with the use of two-layer and one-layer charging [1, 2]. This was the first such study for sinter plants that operate on iron-ore concentrates. The factory tests established the following [1]: 1) the unit gasdynamic resistance of the bottom third of the lower layer of a two-layer charge is 1.8 times greater than that of the middle third and 4 times greater than that of the top third. Thus, the factor which limits sintering rate is not the boundary layer (although it makes its own negative “contribution”), as was stated in [2]. Instead, the limiting factor in this case is the lowest part of the bottom layer; bulk density in this part is greater and the high-temperature range is broader than in the overlying parts of the layer; 2) the average gas-pressure gradient in the lower half of the bottom layer of the charge is about 70% of the total resistance of the layer; 3) the transition to one-layer charging increases the sintering rate by 10%, which confirms that there is a net improvement in the gasdynamic structure of the layer; and 4) the content of the ‐5-mm fraction in the skip sinter rose by 0.2 abs.%.

New model of the sintering process

Dimensional analysis is used to construct a new mathematical model that establishes a closer relationship between the unit productivity of a sintering machine and the parameters of the sintering operation. An analysis is performed to determine how the unit productivity of the sintering machine is affected by the total gasdynamic resistance of the bed, the coarseness of the material being sintered, the unit load complex, and the duration of the sintering operation. gasdynamic resistance of the bed, duration of the sintering operation, height of the bed, bulk density of the charge, coarseness of the material. Modern sinter plants are a complex system of different types of equipment that operate in different regimes and have different technological functions. The growth of sinter production is being accompanied by intensification of the auxiliary and production operations that are performed. The overall increase in sinter output and a tightening of requirements on sin- ter quality and the ability of the various operations to be performed under flow-line production conditions are creating a good opportunity for the broad introduction of automated monitoring and control equipment. Such equipment should be developed by economics- and mathematics-based methods and should maximize the productivity of the sintering machine and make the most efficient possible use of the raw materials, fuel, and capital expenditures while ensuring a certain level of product qual- ity and protecting the environment. Automated systems developed to control sinter production should also improve the orga- nization of production operations and provide for real-time control over the production process. One tool that can be used to automate sinter production is mathematical modeling. The mathematical models which are constructed can be employed to create suitable control algorithms that can work with existing hardware and software. The unit productivity of a sintering machine is one quantitative criterion of the efficiency of the sintering process. The following are the main factors that affect the efficiency of this process: the coarseness and material composition of the material being sintered; the coarseness and quantity of fuel supplied to the charge; the charge's moisture content; the coarse- ness and quantity of undersized sinter; the coarseness and quantities of the various additives that are used; the height of the bed of charge materials on the sintering machine; the vacuum created by the exhauster; the efficiency with which the charge is mixed; the character of the charging operation and the associated segregation of different charge components; the presence of different "sublayers" in the bed of charge materials; the initial temperature of the charge. The studies (1, 2) presented a mathematical model that determines the dependence of the unit productivity of a sin- tering machine W (kg/(m 2 ·sec)) on the total gasdynamic resistance of the charge bed p (kg/(sec 2 ·m), sintering time τ (sec), bed height h (m), the bulk density of the charge ρ (kg/m 3 ), and the coarseness of the material being sintered. The last param- eter is expressed through the equivalent diameter of the balled charge d (m). The model has the form

Industrial catalysts for the hydrogenation of carbon oxides

Conditions for the synthesis, reduction and passivation of methanation catalysts are summarized. Requirements are given for preparing catalysts for use. The basic characteristics of industrial methanation catalysts and the conditions for their use are discussed. It is noted that the NIAP-07 domestic catalysts of the NKM series have a life span of 15 years. It is shown that the new high-performance nickel methanation catalyst has a lower activation temperature and can be manufactured in the form of rings, extrudates, or pellets. The use of a ring-shaped catalyst allows us to reduce the gas-dynamic resistance of a methanator and thus to economize on natural gas in ammonia production units. NIAP-KATALIZATOR has organized industrial production of methanation catalysts. The NIAP-07 (NKM) catalysts can be used in various industrial processes for purifying gases of carbon oxides via their hydrogenation.

Optimization of temperature regime for an industrial claus reactor

On the example of modernizing an SRU catalytic reactor of the elemental sulfur production workshop of the Copper Plant of Norilsk Nikel Mining and Metallurgical Company, the possibility is demonstrated of temperature regime optimization for a Claus industrial reactor. Data are presented for two years of inspection before and after catalytic reactor modernization, indicating that due to a change in the scheme for introducing processing gas there is a reduction by an order of magnitude of the temperature gradient within the catalytic reactor and an almost twofold reduction in its overall gas dynamic resistance.