The hardware-technological scheme is supplied with an equipment specification containing the following data: the number of the apparatus on the diagram and its name, the main characteristics of the apparatus (volume, mass, surface, overall dimensions, the main material for the manufacture of the apparatus) and the number of apparatuses.
The hardware-technological scheme should be drawn on a separate sheet; all devices presented in it must be numbered through numbering, from left to right, clockwise, round.
The hardware-technological scheme has great maneuverability and allows you to work on various options, depending on the quality of the processed raw materials.
The hardware-technological scheme (Fig. XII.1) consists of a screw-type melter 1, melting in which occurs due to the circulation of solutions through a shell-and-tube heater 3, fed by low-pressure steam. The molten suspension enters the thickener 2, from which the thickened part is sent for separation to the centrifuge 4, the drain is partly used as a heat carrier in the melting process, and partly it is sent to the second stage of salting out.
The hardware-technological scheme differs from that described above by the presence of special heat exchangers to ensure the melting of mirabilite. Heating is performed by water, which cools the alcohol vapor in the condenser and further heats the melting slurry.
The hardware-technological scheme of this process includes: a container with a stirrer for separating sodium sulfate into a precipitate; thickener, drum vacuum filter for separating the solid phase and washing it; distillation column for distilling off the organic solvent.
The hardware-technological scheme consists of two vibroextractors 6 m high with 16 plates and three extractor-separators. The initial solution of polysulfone enters the vibroextractor. The extractant is the washing water coming from the second vibroextractor countercurrent to the solution. In each stage of the extractor-separator, the solution is extracted and separated into raffinate and extractant. The purified solution of polysulfone in chlorobenzene is sent for planting.
A typical hardware-technological scheme consists of three schemes-circuits: scheme-circuit of the movement of fats; schemes-contour of the movement of hydrogen and schemes-loop of the movement of the catalyst. In practice, all these schemes are combined into a single interconnected technological scheme of hydrogenation. Below is a description of each circuit diagram.
This hardware-technological scheme can be partially changed depending on specific conditions. If, for example, the acid number of the fat mixture does not exceed 0 5 mg KOH, the mixture is not subjected to alkaline refining.
The hardware-technological scheme for the production of complex NP- and NPK-fertilizers, which provides for separate ammonization of nitric and phosphoric acids and includes the stage of drying the finished product, is practically similar to the technological scheme for the production of ammonium phosphates using an ammonizer-granulator (Fig. VII-3), but differs from it by the inclusion of equipment intended for the production of ammonium nitrate melt, and a unit for supplying potassium chloride to the process.
The hardware-technological scheme of the processes of oxidation, alkylation, condensation, isomerization differs little from the above schemes of reaction apparatuses. Apparatuses can only differ in material, mixer design, type of coolant.
The hardware-technological scheme of the TOR installation is built similarly to the scheme of other plasma-chemical installations shown in Figures 4.20, 4.24, 4.29. The denitration process at the TOP unit was carried out as follows.
The hardware-technological scheme for the production of nitroenamels and nitroprimers is shown in fig. 4.6. The nitro base is obtained according to the scheme (see Fig. 4.1) for obtaining nitro-varnishes, described above (p. Pigment pastes are obtained by dispersing semi-finished pigment pastes in a bead mill, in a ball mill or on a three-roll paint grinder.
The hardware-technological scheme for the production of nitroenamels and nitroprimers is shown in fig. 4.6. The nitro base is obtained according to the scheme (see Fig. 4.1) for obtaining nitro-lacquers, described above (p. Pigment pastes are obtained by dispersing semi-finished pigment pastes in a bead mill, in a ball mill or on a three-roll paint grinder. In addition, dry-rolled pigment pastes (SVP) are used, usually manufactured at enterprises producing colloxylin - SVP study Dry pigments are kneaded with watered colloxylin, dibutyl phthalate and a stabilizer.
The hardware-technological schemes for the production of micro-filters based on fibers and fibrous (fiber-film) materials are very diverse and depend on the type of raw material used and the composition of the composition. These can be cellulosic materials, chemical fiber materials or EPS, which use only one type of anisometric particles. Composite materials can be bulk mixtures of fibrous (fibrous-film) particles of various nature and mixtures of fibrous particles or layered structures.
The equipment and technological scheme of biological treatment includes a biocoagulator, a primary settling tank, aeration tanks-mixers, secondary settling tanks, gravel-sand filters, a ruff mixer and a contact tank for disinfection with sodium hypochlorite, a sludge thickener, and a dehelminthizer for disinfecting sediments.
Modern hardware and technological schemes for the production of fertilizers make it possible to combine several stages of the process in one apparatus. Thus, the stage of mixing the components is often combined with the stage of granulation in hardware.
Hardware-technological scheme for obtaining uranium hexafluoride. The hardware-technological scheme for the recovery of uranium hexafluoride includes units for supplying reagents, measuring and controlling their consumption; recovery reactor; equipment for dedusting gases and extracting hydrogen fluoride from them, a burner for burning hydrogen and a cooling and packaging system for uranium tetrafluoride. To supply uranium hexafluoride to the reactor, the containers in which it is transported are heated to a certain temperature. For this purpose, it is necessary to use at least two containers, so that after emptying one of them, immediately start feeding hexafluoride into the reactor from the second container.
The hardware-technological scheme for processing the polyhalite of the Zhilyanskoye deposit into a chlorine-free potassium-nitrogen-magnesium fertilizer (nitrokalimag) is shown in fig. III. Polyhalite ore after hammer crusher / with a particle size of 5 - 10 mm enters the rod mill 2, which simultaneously serves in a given ratio of recycled solution.
The hardware-technological scheme of a working or projected enterprise, workshop or site must be presented in such a way that it can be used to evaluate, analyze and calculate the main indicators of the technological process, the flows of basic and auxiliary materials, the main and auxiliary technological equipment, to detect bottlenecks in production, energy costs.
The hardware-technological scheme includes distillation units for methylene chloride with impurities of other volatile substances; settling; rectification for isolation from the organic phase of methylene chloride; neutralization; filtering; evaporation; calcination and burning; sorption purification of evaporation distillate.
After the material calculation and selection of equipment, an equipment specification is drawn up for hardware and technological schemes.
On the hardware-technological scheme, all technological equipment is drawn without exception. Apparatuses are depicted in a simplified way and applied to the diagram to scale. Each device on the hardware-technological scheme is depicted as a sketch that is not too detailed, which should still reflect the fundamental features of the device.
When designing hardware-technological schemes, one should be guided by a number of symbols adopted in the practice of designing industrial enterprises.
After drawing up the hardware-technological scheme and material calculation, the calculation and selection of process equipment is carried out. The purpose of the calculation is to identify the main design dimensions of the equipment, the type and number of installed devices.
Three versions of the hardware-technological scheme for the production of calcium dimonophosphate with the maximum use of the equipment of existing workshops for the production of phosphorus-containing fertilizers have been developed.
The nitro base is obtained according to the hardware-technological scheme for obtaining nitro-lacquers (see p. After mixing the semi-finished products and typing, the lacquer is cleaned in centrifuges of the SGO-100 type. After drying, the lacquer forms an elastic film with high gloss. It is used for dyeing leather black.
The nitro base is obtained according to the hardware-technological scheme for obtaining nitro-varnishes (see p. After mixing the semi-finished products and typing, the varnish is cleaned in centrifuges of the SGO-100 type. After drying, the varnish forms an elastic film with high gloss. It is used for dyeing leather black.
Scheme of dehydration of mirabilite by the method of melting - evaporation. The paper presents a hardware-technological scheme, according to which mirabilite, obtained by cooling vacuum crystallization, enters the reactor for melting. The heat carrier is a melt heated by heat exchange at the stage of organic solvent vapor condensation.
On fig. 3.2 shows a hardware-technological scheme for obtaining enamels and primers using paint-grinding machines.
Hardware-technological scheme for the production of magnesium chloride in a shaft electric furnace. On fig. 32 shows the hardware-technological scheme for the production of magnesium chloride in shaft electric furnaces.
On fig. 31 shows the hardware-technological scheme of sludge pulp filtration.
Scheme of phase fields of the system Na2O - Al2O3 - Na2O - Fe203 - 2CaO - SiO2.| Scheme of sintering bauxite-soda-lime charge. On fig. 53 shows an exemplary instrumental-technological scheme for sintering a bauxite-soda-limestone charge. The initial charge from the mixer is fed through a pressure distribution pipeline through a nozzle into a tubular rotary kiln, where it is sintered. The resulting cake from the furnace is poured into a drum cooler, cooled in it and fed to crushing by a conveyor. The sinter crusher works in a closed cycle with a roar.
Scheme of the UV-05 water treatment plant. On fig. 7.4 shows a simplified hardware-technological scheme of the UV-05 water treatment plant. Electricity consumption is 1 - 12 kWh per 1 m3 of treated water.
In 1958 - 1959 the hardware-technological scheme was tested in laboratory conditions.
Depending on the conjuncture of demand, the instrumental and technological scheme of the operating catalyst production of the first stage of the plant allows the production of zeolites LaKh, Les.
The hardware-technological scheme of the stages of oxidative roasting of the charge and leaching of the sinter. On fig. 7 shows one of the hardware-technological schemes of the stages of oxidative roasting of the charge and leaching of the sinter.
Scheme of a sequential variant of the combined method Bayer - sintering. Another disadvantage of the consistent Bayer variant - sintering is the bulkiness of the hardware-technological scheme due to the two-stage processing of raw materials.
In the production of semiconductor materials, as can be seen from the hardware-technological schemes for obtaining elementary semiconductors (see Fig. 3.1 and 3.3), a large number of different devices are used. Many of them, especially at the production stage of polycrystalline semiconductors, belong to apparatuses of general chemical technology. These are distillation columns, scrubbers, condensers, absorbers, etc. The principal structural diagrams of these apparatuses are relatively simple and do not require special explanation. The most responsible in the general chain of devices are installations for obtaining the final product - semiconductor single crystals.
Thus, within 7 months of this year. in the complex, an instrumental and technological scheme for the processing of halite-lang-bainite residue at table salt for diaphragm electrolysis and sulfate salts and magnesium, which will significantly reduce the time for mastering production capacity and ensure the achievement of design technical and economic indicators.
Structural-technological scheme of TPBO processing. On fig. 8.36 shows the structural and technological, and in fig. 8.37 - basic hardware-technological scheme for the processing of TPBO.
In order to reduce the cost of the water purification process, it is necessary to strive for the maximum simplification of the hardware-technological scheme and its automation, as well as the use of high-capacity devices and cheap reagents for minimum flow the latter.
Scheme of the process of obtaining uranium tetrafluoride. From the description of the scheme, in which only the most important nodes of the hardware-technological scheme are indicated, we can conclude that the production is complex, which is described by only two chemical equations.
Technology system- this is a sequence and a list of technological operations fixed in one way or another that must be performed in order to turn the feedstock into a finished product. Target drawing up a diagram is a visual representation of the sequence of the technological process of production.
The simplest scheme is vector. It depicts each operation with simple geometric figures with appropriate explanatory inscriptions and arrows, but does not reflect the apparatus in which the process is carried out, vehicles, do not indicate the use of water, steam, refrigerants, production waste.
The most appropriate is the picture hardware-technological scheme, in which the drawings reproduce in basic terms the contours of the machine on which this or that operation will be performed.
Draw a hardware-technological scheme, starting with the acceptance of raw materials and ending with storage finished products strictly following the flow of the process.
The scheme is drawn from left to right or from top to bottom, which is determined by the direction of the technological production flow. In the production building of the plant, the location of the equipment does not always meet this requirement. In view of this, when drawing up a technological scheme, it is necessary to abstract from the relative position of the equipment in the building of the enterprise and place the equipment on the sheet along the production flow.
The equipment is drawn on the flow diagram in the form of a contour resembling the depicted object, on an arbitrarily chosen scale, but with respect to relative dimensions (proportionality), indicating the main design features (jackets, coils, mixers, etc.).
Only the number of units of the equipment of the same name (for example, fermenters) is drawn, which is necessary for a complete representation of the sequence of technological processes (most often one piece of equipment is depicted, regardless of how much actually happened during the calculation).
The image of machines and devices should be placed at intervals necessary for the supply and removal of various communications.
The main product flow, starting with raw materials, is shown throughout the diagram as a solid thick line. It is supplied and discharged to those points that are provided for by the design of the equipment. At the inlet and outlet, arrows in the form of equilateral triangles indicate the direction of product movement. Communications should not cross the image of the equipment.
With a long length of product communication, it can be interrupted and at one end of the interrupted line write what and to what position according to the scheme should be assigned, and at the other end of the gap - what and from which position is summed up. For example: “wort from pos. 25, yeast to pos. 70".
In addition to the main product communication, the diagram shows the supply of water, steam, carbon dioxide, refrigerant, etc., spent on technological needs.
On communications showing the input of raw materials into production, the removal of finished products, waste, inscriptions are made indicating where the raw materials come from and where this or that product or waste is removed. For example: “hops from the warehouse”, “grain for sale”.
The choice of technological schemes of production is one of the main tasks in the design of industrial enterprises, since it is the technological scheme that allows you to determine the sequence of operations, their duration and mode, as well as determine the place of supply of auxiliary components, spices and containers, allows, with a sufficiently full load of equipment, to reduce duration technological cycle, increase the yield of products and reduce losses at individual stages of processing, eliminate the deterioration of the quality of raw materials during processing. At the same time, modern trends in the technology of manufacturing individual product groups and the introduction of new progressive equipment should be taken into account.
The technological scheme of production is a sequential list of all operations and processes for processing raw materials, starting from the moment it is received and ending with the release of finished products, indicating the processing decisions made (duration of operations or process, temperature, degree of grinding, etc.)
At the projected enterprise, in accordance with the task, whole-muscle and restructured products, fried sausage and semi-finished meat and bone products are produced.
Raw materials can be supplied to production in a chilled and frozen state. It is preferable to use chilled meat, as it has higher functional and technological properties. When using frozen meat, it must first be defrosted. For this purpose, the enterprise provides defrosting chambers. The defrosting of raw materials is carried out in an accelerated way, with a steam-air mixture, which reduces weight loss, and this, in turn, reduces the loss of meat juice and, as a result, water-soluble proteins, vitamins, nitrogenous extractives, mineral components, and also reduces the duration of the process.
Overhead tracks are used to move carcasses from the defrosting and accumulation chambers to the raw material department, which makes it easier to transport raw materials. The overhead track is also used in cleaning and cutting operations, which will also facilitate the work of workers, as well as reduce the contamination of raw materials, and, consequently, improve the quality of finished products.
Instead of a platform for cutting carcasses in the raw material section, a hanging path is provided parallel to the tables for highlighting anatomical parts. This will reduce the time and effort for transporting raw materials to workers performing cutting.
Ambassador of deli products is produced by injecting brine into the product on a multi-needle syringe PSM 12-4.5 I. Injection of brine allows you to reduce the salting time, improve the microbiological state, and get a juicy product. And the use of this injector is due high speed injection, as well as the uniform distribution of the brine inside the product due to the large number of needles, in addition to the injector PSM 12-4.5 I, it is possible to inject brines with increased viscosity.
Then the sprinkled raw material is subjected to massaging. The massaging process is a kind of intensive mixing and is based on the friction of pieces of meat against each other and against the internal walls of the apparatus.
The massaging operation allows to reduce the salting time, contributes to a more complete distribution of the curing ingredients inside the product, and, consequently, improves the functional and technological properties of the raw materials, and hence the quality of the finished product.
To implement the massaging process, the projected enterprise provides equipment: VM-750, MK-600, UVM-400, which allows massaging in a vacuum environment, with a depth of up to 80%, and this increases the positive effect of the process, the use of pulsating vacuum, causes additional contraction / relaxation of muscle fibers.
Hams are a restructured product. Raw materials are pre-crushed in the form of a meal (16-25 mm) on the top ShchFMZ-FV-120, during mechanical grinding, the cellular structures of muscle fibers are partially destroyed, which contributes to a further increase in the intermolecular interaction of muscle proteins and curing ingredients.
Then the raw materials are processed in the Eller Vacomat-750 massager with the addition of brine and further massaging. Manufactured hams are a product with an increased yield. This is possible due to the soy protein contained in the brine preparation, which makes it possible to increase water-binding, gel-forming and adhesive abilities. Soy protein can also improve tenderness, juiciness, texture, consistency, color and shelf life of products.
Massaging small pieces allows you to shorten the process of massaging and ripening, and also makes it possible to use scraps and residues from large pieces of raw materials. In order to avoid foam formation during massaging, a vacuum massager is used, which also has a positive effect on color and consistency.
Minced meat of semi-smoked (fried) sausages with salting is prepared in a meat mixer SAP IMP 301, with low power and power consumption, which helps to reduce energy costs.
For forming loaves of fried sausage, hams "Onega", "In the shell" and Nut "Special", use the Universal vacuum syringe (semiautomatic) V-159 Ideal. The use of vacuum in the molding process prevents additional aeration of raw materials, provides the necessary packing density, which leads to high organoleptic characteristics of the finished product, the likelihood of fat oxidation disappears and the product's storage stability increases.
The molding of hams is carried out in an artificial shell "Amiflex", which avoids the appearance of undercooked or overcooked loaves. Due to the uniformity of the caliber, high elasticity makes it possible to obtain a long loaf with a smooth surface, no losses during heat treatment and storage; excellent presentation (no wrinkling) of the finished product throughout the entire - expiration date; the possibility of typographic marking, clipping, a wide choice of colors.
The use of clippers KORUND-CLIP 1-2.5 and ICH "TECHNOCLIPPER" makes it possible to increase labor productivity to reduce the share manual labor, the possibility of dosing along the length, ensuring the required density of stuffing loaves.
Heat treatment hams and delicatessen products are produced in ElSy ETOM universal thermal chambers equipped with smoke generators. The advantage of this equipment is that the chamber can operate in a wide temperature range (up to 180 0 C), allowing heat treatment for almost any product. The cameras are also equipped program management, set standard programs processing and the possibility of their correction.
For cutting bone and semi-finished products obtained from butchering, a band saw PM-FPL-460 is used, it has a small installed power, which reduces energy costs.
All the equipment in the technological schemes is modern, allowing many times to reduce the time of the technological process, due to functionality, improve product quality and improve productivity.
Hardware and technological design of processes
primary oil refining
Rectification of simple and complex mixtures is carried out in columnsperiodical or continuous actions.
Batch columns are used in low-capacity plants where a large number of fractions must be collected and the separation must be high. The components of one of these installations are (Fig. 1) a distillation cube 1, a distillation column 2 , capacitor 3, fridge 5 and containers. The feedstock is poured into a cube to a height equal to 2/3 of its diameter. Heating is carried out with deaf steam. In the first period of operation of the distillation unit, the most volatile component of the mixture is taken, for example, the benzene head, then the components with a higher boiling point (benzene, toluene, etc.). The highest-boiling components of the mixture remain in the cube, forming a VAT residue. At the end of the rectification process, this residue is cooled and pumped out. The cube is again filled with raw materials and rectification is resumed. The periodicity of the process is due to greater heat consumption, lower labor productivity and less efficient use of equipment.
Plants with continuous columns do not have these drawbacks. circuit diagram such an installation for separating a mixture of pentanes is shown in fig. 2. The plant consists of a raw material preheater 1, distillation column 2, heat exchangers 3 , condenser-refrigerator 4 and boiler 5. The heated raw material is introduced into the distillation column, where it is separated into liquid and vapor phases. As a result of rectification, isopentane is taken from the top of the column as the main product and from the bottom of the column - n-pentane as a residue.
Depending on the number of products obtained in the separation of multicomponent mixtures, there are simple and complex distillation columns. In the first, two products are obtained during rectification, for example, gasoline and semi-fuel oil. The latter are designed to produce three or more products. They are simple columns connected in series, each of which separates the mixture entering it into two components.
Each simple column has a stripper and a concentration section. The stripping or stripping section is located below the input of raw materials. The plate on which the raw material for separation is fed is called the feed plate. The target product of the stripping section is a liquid residue. The concentration or strengthening section is located above the food plate. The target product of this section are rectified vapors. For normal operation of the distillation column, it is necessary to supply irrigation to the top of the concentration section of the column and introduce heat (through the boiler) or live water vapor into the stripping section.
Depending on the internal device that provides contact between the ascending vapors and the descending liquid (reflux), distillation columns are divided into packed, disc, rotary etc. Depending on the pressure, they are divided into distillation columns high pressure atmospheric and vacuum. The former are used in the processes of stabilization of oils and gasolines, gas fractionation in cracking and hydrogenation units. Atmospheric and vacuum distillation columns are mainly used in the distillation of oils, residual oil products and distillates.
Choice of trays for distillation columns
There can be no single answer to the question of which of the plates is the best. In each case, the choice of plate type requires careful justification. The distillation column must work satisfactorily, taking into account possible fluctuations in the load of raw materials and provide a given clarity of distillation at a minimum of operating costs and specific capital investments.
In the oil refining industry, bubble trays have become the most widely used and have accumulated considerable data on their performance, so they usually serve as a benchmark for comparison with other tray designs. Comparative characteristics of various plates are given below.
These data show that bubble-cap trays perform worse than other trays in a number of ways. Therefore, in many plants under construction and in operation, new types of trays are replacing cap trays. The advantage of lattice, sieve and valve trays is not only lower cost, but also greater productivity, low hydraulic resistance, less carryover of liquid droplets by the ascending vapor flow, and other important factors.
Data published in the literature show that the relative cost of manufacturing (without installation) 1 m 2 the surface of the plates is: capped 100%; plates with round valves 70%; sieve, lattice and with S-shaped elements 50%.
Irrigation types
Heat removal from the top of the column for the formation of irrigation is carried out by one of the following methods: hot irrigation (using a partial condenser); evaporative circulation (cold) irrigation; non-evaporative circulating irrigation.
Hot irrigation is supplied using a partial condenser - tubular or coiled, it is installed above the distillation column or inside it (Fig. 3, a). The cooling agent is water or another refrigerant, less often raw materials. The vapor entering the annular space is partially condensed and returned to the upper plate in the form of hot spray.
Due to the difficulty of installing and repairing a partial condenser, this method of creating irrigation has received limited use, mainly at low-capacity plants in the rectification of non-aggressive raw materials.
Cold irrigation is organized according to the scheme (Fig. 3, b). Couples exit from the top of the column 1 and pass through the condenser 2. The condensate is collected in a container. 3, from where it is partially pumped back to the distillation column as cold irrigation, and the balance amount of rectified product is discharged as a finished product.
Circulating non-evaporative irrigation (Fig. 3, in) from the first or second plate is pumped through the heat exchanger 4 and refrigerator 5 on the top plate. The heat-receiving medium in the heat exchanger is usually the raw material, which is heated in this way.
Circulating irrigation is sometimes combined with cold evaporation. The amount of the latter in such cases is limited and is used mainly for more precise control of the temperature at the top of the column. At installations for direct distillation of oil using complex columns, circulating irrigation is organized in two or three intermediate sections. Intermediate circulating irrigation allows unloading the distillation column in the upstream sections, as well as enhancing the preheating of raw materials and reducing the heat load of the furnaces.
The introduction of circulating irrigation has made it possible to significantly increase the productivity of oil distillation plants. For its implementation, more powerful pumps are needed to pump more liquids. Pumping is accompanied by a slightly increased energy consumption, which, however, is more than offset by the savings in fuel and water.
Heat supply down the column
AT industrial practice it is carried out using a tube bundle mounted directly into the column (Fig. 4, a), a heat exchanger - conventional or with a steam space (Fig. 4, b, c) or a hot jet circulating through a tube furnace (Fig. 4, G). The heat supplied to the bottom of the column evaporates part of the liquid, forming the vapor flow necessary for distillation, and heats the residue to a temperature higher than on the bottom plate of the stripping section.
Rice. 4. Ways of heat supply down the column:a - a bundle of heat exchange pipes mounted in a column; b - remote vertical boiler; in- boiler with steam space; G- hot jet.
The use of a tube bundle inside the column is possible only if there is a relatively small heat exchange surface, a non-corrosive environment and a clean coolant.
The most common method of heat supply is the use of standard horizontal or vertical heat exchangers and boilers. In the case of the former (see Fig. 4, b) it is necessary that the liquid moves in them from the bottom up, preventing the formation of vapor locks. When heat is supplied from the boiler with a vapor space (see Fig. 4, c), the liquid from the bottom of the column enters the boiler, passing through which it flows through the partition into the left section of the apparatus and is removed from there as the final product. When passing between the tubes of the heat exchanger, the liquid partially evaporates, heating up from the temperature on the lower plate of the stripping section to the temperature at the outlet of the boiler. The vapors formed in it return to the distillation column, under the bottom plate. A constant liquid level behind the baffle of the boiler is maintained by a level regulator.
When heat is supplied with a hot jet (see Fig. 4, G) liquid from the lower plate is pumped through a tube furnace, where it is given the required amount of heat Q . From the furnace, the mixture of vapors formed and the heated liquid is returned to the column.
Temperature regime of distillation column
The temperature regime is one of the main parameters of the process, the change of which regulates the quality of rectification products. The most important control points are the temperatures of incoming raw materials and rectification products leaving the distillation column.
When calculating distillation columns for the separation of oils and oil fractions, the temperature regime is determined using the curves of single evaporation (OI). The lighter the oil to be distilled, the flatter the RI curve, and the lower the pressure in the evaporator and the given fraction of distillation, the lower the oil temperature at the column inlet. As the practice of the operation of tubular plants has shown, oil distillation at atmospheric pressure is carried out at temperatures at the inlet of raw materials to the distillation column of 320-360 ° C. Fuel oil distillation is carried out in a vacuum and at a temperature at the outlet of the furnace not higher than 440 ° C. Heating oil heating temperature in the furnace limited by its possible decomposition and deterioration in the quality of the resulting oil distillates (viscosity, flash point, color, etc.).
Methods for constructing RI curves .
The RI curve for oil or oil product can be built either by the analytical method developed by Professor A. M. Tregubov for a multicomponent mixture, or by using empirical graphs proposed by a number of authors. The analytical method gives more accurate results, but requires relatively complex and lengthy calculations. Empirical methods for constructing the RI curve are simple and convenient in computational practice, but are less accurate, especially for oils and oil residues. The basis of empirical methods are plots of the slope of the ITC or Engler (ASTM) curves against the slope of the RI curve. These include the methods of Pirumov, Nelson, Obryadchikov and Smidovpch, etc. The method of Obryadchikov and Smidovich, based on the use of the graph shown in Fig. 5. The procedure for constructing the RI curve is as follows. Calculate the slope of the ITC curve according to the equation:
|
and find the temperature of 50% distillation. According to the graph, from the point corresponding to the slope of the ITC curve, the perpendicular is lowered and restored until it intersects with the curves corresponding to the temperatures of 50% distillation of the studied oil product according to the ITC. From the points of intersection with the named curves, horizontal lines are drawn, which are cut off on the ordinate axis of the amount of distillation (in%) according to
ITC curve corresponding to the temperatures of the beginning and end of a single evaporation.
Fig.5
Determination of the main dimensions of the column. Number of plates.
Methods for determining the number of theoretical plates in a column are divided into analytical and graphic. Analytical methods give more accurate results, but are laborious; in modern conditions, the use of these methods is facilitated by the use of computers. Graphical methods are less accurate, but convenient and illustrative, of which the McCabe and Thily method has been widely used.
The required number of theoretical plates depends on a number of parameters, mainly on: the difference in the boiling points of the separated components of the mixture (the value of the coefficient of relative volatility); clarity of distillation, i.e., on the composition of the resulting rectified product and residue; phlegm number, i.e. from the multiplicity of irrigation to rectified. The smaller the difference between the boiling points of the separated components of the mixture, the more flat the equilibrium curve and the more trays are required.
The relationship between the boiling points of the separated components of the mixture and the number of theoretical plates is characterized by the Bragg and Lewis plot (Fig. 6), which is based on the equation:
In order to increase the clarity of the head division, it is necessary to increase the number of theoretical plates, and vice versa. The most difficult thing is to obtain products of high purity. The required number of theoretical plates also depends on the multiplicity of irrigation: the greater the multiplicity of irrigation to rectified, the less plates are required, and vice versa. An increase in the number of trays increases the height of the distillation column, and hence its cost, while an increase in the amount of reflux increases the operating costs associated with the consumption of heat in the boiler and water in the condenser. The optimal amount of irrigation is the amount at which the total cost is minimal.
Heat exchangers in the petrochemical industry
Heat exchangers are an integral part of almost all technological installations in oil refineries and petrochemical plants. Their cost is on average 15% of the total cost of equipment of technological installations. Heat exchangers are used for heating, evaporation, condensation, cooling, crystallization, melting and solidification of the products involved in the process, as well as steam generators or waste heat boilers.
The media used to supply or remove heat are called heat carriers and refrigerants, respectively. Heated gaseous, liquid or solid substances can be used as heat carriers. Flue gases as a heating coolant are usually used directly in plants where fuel is burned, since their transportation over long distances is difficult. Hot air as a heat transfer fluid is also used in many petrochemical processes. A significant disadvantage of heating with flue gases and hot air is the bulkiness of heat exchange equipment due to their relatively low heat transfer coefficient.
Water vapor as a heat carrier is mainly used in a saturated state, both at high pressure and exhausted from steam engines and pumps. The advantage of saturated water vapor is its high heat of condensation, so relatively little heat transfer fluid is required to transfer even a large amount of heat. High heat transfer coefficients during the condensation of water vapor make it possible to have relatively small heat exchange surfaces. In addition, the constancy of the condensing temperature facilitates the operation of the heat exchangers. The disadvantage of steam is a significant increase in pressure associated with an increase in saturation temperature, which limits its use to a final heating temperature of the substance of 200-215 ° C. At higher temperatures, high steam pressure is required, and heat exchangers become metal-intensive and expensive.
In the oil refining industry, highly heated distillates and distillation residues, as well as oil vapors, are widely used as heat carriers. In a number of cases, highly heated bulk solids are used, including solid catalysts and coke, as well as special liquid heat carriers: diphenyl, diphenyl oxide, silicones, and highly superheated (under a pressure of 220am) water. All these heat carriers allow heating only up to 250 ° C. Above this temperature, heat transfer is carried out - with the help of fire heaters - tube furnaces. For heating to high temperatures, sometimes liquid alloys with a high boiling point are used: alloy NaN 0 2 (40%) + KN 0 3 (53%) + NaN 0 3 (7%) with a boiling point of 680°C, alloy NaCl + AlCl 3 + FeCl 3 in molecular ratio 1:1:1s boiling point 800°C.
Classification of heat exchangers in oil technology
According to the mode of action, heat exchangers are divided into surface and mixing devices. The first group includes heat exchangers in which heat exchange media are separated by a solid wall. In mixing heat exchangers, heat transfer occurs without a separating partition by direct contact between heat exchange media. An example is a mixing condenser (scrubber) filled with packing. The liquid flows from top to bottom, vapors or gas move countercurrent to it. In refineries, surface heat exchangers are predominantly used. According to their design, they are divided into serpentine, "pipe-in-pipe" type and shell-and-tube - with fixed
tube sheets, U-tubes and floating
head.
According to the installation method, vertical, horizontal and inclined heat exchangers are distinguished. Vertical heat exchangers take up less space, but are less easy to clean. In refineries, horizontal heat exchangers are most widely used.
Condensers and refrigerators in oil technology
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The first are designed to condense vapors, and the second - to cool products to a predetermined temperature. These devices are made in the form of coils from smooth or finned tubes or in the form of single- and multi-pass shell-and-tube devices. Immersion condensers and sectional-type refrigerators have become widespread at refineries, less often - irrigation refrigerators; in recent years, air coolers have been increasingly used. Mixing condensers (scrubbers) are also used.
Tube furnaces in oil technology.
Tube furnaces are the leading group of fired heaters in most process plants in refineries and petrochemical plants. The first tube furnaces were fire type with an upward flow of flue gases. In these furnaces, the upper rows of serpentine tubes were thermally underloaded, while the lower rows were overloaded and often burned out; the efficiency of these furnaces was also low.
Convection ovens have replaced the campfire ovens.
in which the pipe coil is separated from the combustion chamber of the saddle
wall. By shielding the combustion chamber and increasing its volume, normal conditions were created for the operation of the coil.
Oil refineries and especially gas refineries
factories have found the use of vertical cylindrical furnaces
with pipes located on the surface of the cylinder (Fig. 8). This achieves a uniform thermal load of the pipes. Such furnaces are compact and transportable, the intensity of their furnace space reaches 75,000 kcal/(m 3 * h). At the top of the fire heater, a heat-resistant steel cone is suspended, which contributes to
uniform heating of raw materials along the length of the pipes as a result of increasing
flue gas flow rate at the top of the furnace.
Industrial installations for the primary processing of oils and fuel oils
Primary processing (direct distillation) is the process
obtaining oil fractions differing in boiling point, without thermal decomposition of the components that make up the distillate. This process can be carried out in bottom or tubular plants at atmospheric and elevated pressures or in vacuum.
At the present stage of oil refining, tubular units
are part of all oil refineries and serve
suppliers of both commercial petroleum products and raw materials for secondary processes (catalytic cracking, reforming, hydrocracking, coking, isomerization, etc.).
The widely used secondary methods of oil refining have increased the requirements for the clarity of distillation, for a deeper selection of medium and heavy fractions of oils. In connection with these requirements, refineries began to improve the design of distillation columns, increasing their
the number of plates and increasing their efficiency, apply a secondary
distillation, deep vacuum, antispray agents, antifoam additives, etc. Along with the increase in the capacity of primary oil refining plants, this process began to be combined with other technological processes, primarily with dehydration and desalting, stabilization and secondary distillation
gasoline (in order to obtain narrow fractions), with catalytic
cracking, coking, etc. The productivity of some installations for the primary processing of oils reaches 200 thousand tons per year.
Depending on the pressure in the distillation columns, tubular installations are divided into atmospheric (AT), vacuum (VT) and atmospheric vacuum (AVT). According to the number of evaporation stages, tubular installations are distinguished
single, double, triple and quadruple evaporation. At installations of single evaporation from oil in one distillation column at atmospheric pressure, all distillates are obtained - from gasoline. The rest of the distillation is tar. At double evaporation plants, distillation to tar is carried out in two stages: first, at atmospheric pressure, oil is distilled to fuel oil, which is then distilled in vacuum until tar is obtained in the remainder. These processes are carried out in two distillation columns; in the first of them atmospheric pressure is maintained, in the second - vacuum. Double evaporation of oils to fuel oil can also be carried out at atmospheric pressure in two distillation columns; in the first, only gasoline is taken and the distillation residue is stripped oil; in the second, stripped oil, heated to a higher temperature, is distilled to fuel oil. Similar two-column
installations belong to the group of atmospheric (AT).
At triple evaporation plants, oil is distilled in three columns: two atmospheric and one vacuum. A variation of the triple oil evaporation unit is the AVT unit with one atmospheric and two vacuum columns. The second vacuum column is designed for post-evaporation
tar, it maintains a deeper vacuum than in the main vacuum column.
The quadruple evaporation plant is an AVT plant with an atmospheric topping column at the head and a post-evaporation vacuum tar column at the end.
Let us consider in more detail the schemes of tubular installations.
Atmospheric, vacuum and atmospheric-vacuum tubular installations
Oil Flash Units
At these units, stabilized and desalinated oil (Fig. 9) is pumped through heat exchangers 4 and the tube furnace coil 1 into distillation column 2; superheated water vapor is fed down the column. Fractions differing in boiling point are taken from the column: gasoline, naphtha, kerosene, gas oil, solarium and others.
Low-boiling components from the naphtha fraction are distilled off in the stripping column 5, equipped with a boiler. The unit processes up to 1000 tons/day of light oil. The yield of fractions is: gasoline 26-30%, naphtha
7-14%, kerosene 5-8%, gas oil and solar 19-20%,
light and heavy paraffin distillates 15-18%, the rest is tar.
The positive features of a single-stage tubular installation are a smaller number of devices and, as a result, a smaller
length of communication lines; compactness; smaller area
occupied by the installation; lower heating temperature of raw materials in the furnace; lack of vacuum devices; lower fuel and steam consumption. The disadvantages of such installations include high hydraulic resistance to the flow of raw materials in the heat exchangers and furnace pipes and, as a result, increased energy consumption to drive the raw pump; increased back pressure in the pipes and casing of the heat exchange equipment and, in connection with this, the likelihood of oil getting into distillates in case of violation of the tightness of the heat exchangers.
Installations of double evaporation of oil to fuel oil
These units are characterized by preliminary partial evaporation of oil
before entering the tube furnace. Evaporation can take place in an evaporator (hollow column) or in a fractionating column with trays. The evaporator is used in cases where the raw material is stabilized (degassed), slightly watered and not containing hydrogen sulfide oil. Oils containing dissolved gases (including hydrogen sulfide), water and salts,
sent to the topping distillation column.
Double evaporation installations, in which a separate distillation column is installed instead of an evaporator, are widely used. At such units (Fig. 10), oil I is pumped in several parallel flows through a group of heat exchangers 7 into the middle part of the pre-evaporation column 2. Gasoline and water vapors, together with hydrocarbon gases dissolved in oil and hydrogen sulfide, pass through a condenser-refrigerator 6 into a gas separator 5. Gas III from the gas separator is sent to the gas fractionation plant, and gasoline is partially fed into the column as irrigation, the rest of its amount is fed to the stabilization column 4. The main product of this pressure column is liquefied gas IV, also sent to the gas fractionation plant.
The topped oil II from column 2 is pumped through the coil of the furnace 1 into the main column 3 under the 7th plate, counting from the bottom. In total, there are 40 plates in the column. Its main product is heavy gasoline V, the vapors of which, after passing through the condenser-refrigerator 6, enter the gas separator 5, and from there, partly for irrigation into column 3, and the rest after leaching and washing with water for compounding with stable gasoline VI from
columns 4. Fractions VII aviation kerosene, diesel fuel and from the bottom of the column 3 fuel oil.
Vacuum plants for the distillation of fuel oil
During vacuum distillation, oil distillates are obtained from fuel oil, differing in boiling points, viscosity and other properties,
as the remainder - half-tar or tar. Vacuum plants
(VT) are divided into fuel and oil. in fuel plants
a wide fraction up to 550 ° C is taken from fuel oil - vacuum gas oil, which is used as a feedstock for catalytic cracking or hydrocracking.
The requirements for the accuracy of distillation when selecting a wide fraction are less stringent than when selecting oil distillates: it is mainly necessary to prevent the smallest droplets of tar from entering the vacuum gas oil so that the content of organometallic compounds poisoning the catalyst does not increase in it, and so that coke formation does not increase during cracking.
To do this, anti-foaming additives such as silicones are used and fenders made of pressed or corrugated metal mesh are installed above the place of input of raw materials.
For a clearer separation of oil fractions, fuel oil is distilled in two-column installations. According to one of the options in the first vacuum column select a broad oil fraction, and in the second vacuum column with a large number of plates, this fraction is separated into narrower fractions. According to another variant of two-column distillation, fuel oil is distilled in two series-connected vacuum columns. In the first column, lighter distillates and semi-tar are taken, which enters the second column to produce viscous distillates and tar.
An example of the first option is the diagram of a vacuum installation (Fig. 11). At this plant, in the first vacuum column 2, distillate II is taken as the main product ( 
Atmospheric vacuum plants
Vacuum tubular installations are usually built in a single complex with an atmospheric oil distillation stage. Combination of atmospheric processes
and vacuum distillation in one unit has the following advantages: reduction of communication lines; fewer intermediate tanks; compactness; serviceability; the possibility of a more complete use of the heat of distillates and residues; reduction of metal consumption and operating costs; great labor productivity.
On fig. 12 shows a technological scheme of an atmospheric-vacuum installation of a fuel profile designed for the processing of sour oil. The gas oil taken from the top of the vacuum column is a broad fraction and is used as a feedstock for catalytic cracking.
Combined installations
The ever-increasing capacity of oil refineries under construction and design requires that they be equipped with a minimum
the number of technological installations, which reduces capital investments,
reduces the construction time of factories. The solution to this problem is achieved both by increasing the productivity of technological installations, and by combining processes in one installation.
Various combinations of processes on one installation are possible:
ELOU - AVT; AWT - secondary distillation of wide gasoline
factions; primary oil distillation - catalytic cracking
vacuum gas oil - destructive distillation of tar; primary distillation of oil - coking of fuel oil in a fluidized bed of coke.
ELOU - AVT installations
The technological scheme of the combined installation ELOU - AVT is shown in Fig.13. Heated in heat exchangers 5 oil I with a temperature of 120-140 ° C in dehydrators 1 is subjected to thermochemical and electrical dehydration
and desalination in the presence of water, demulsifier and alkali.
Oil prepared in this way is additionally heated
in other heat exchangers and with a temperature of 220 ° C enters column 2. On top of this column, a fraction of light gasoline XV is taken. Residue III from the bottom of column 2 is fed into furnace 7, where it is heated to 330°C, and enters column 3. Part of the oil from furnace 7 is returned to column 2 as a hot jet. Top of column 3
heavy gasoline XVII is selected, and from the side through the stripping columns
11 fractions VI (140-240, 240-300 and 300-350°C). Fuel oil IV from below
column 3 is fed into furnace 15, where it is heated to 420 ° C, and enters
into vacuum column 4 operating at residual pressure
60 mmHg Art. Water vapor, gaseous decomposition products and light vapors XIV from the top of the column 4 enter the barometric condenser 12, uncondensed gases are sucked off by the ejector 1.3. The side straps of column 4 are fractions VII, the remainder is tar VIII. Gasolines IV and XVII, obtained from columns 2 and 5, are mixed and diverted to stabilizer 5. After compression, gas from gas separators 10 is fed into absorber 6, irrigated with stable gasoline V. Dry gas XII is discharged to furnace nozzles. Head
the stabilization product of column 5 is sent to the HFC. Stable gasoline undergoes alkalization.
The process of obtaining rubber includes the following main stages:
The stage of preparation of the charge;
Stage of preparation of the catalytic complex (s/s);
continuous polymerization.
The polymerization is carried out in a stage of two polymerizers connected in series, cooled by brine. The polymerizer is a vertical cylindrical apparatus with a capacity of 20 m3, equipped with a jacket through which the refrigerant circulates (polymerization enthalpy 1050 kJ / kg), and a spiral agitator with blades and scrapers that ensure continuous mixing and cleaning of the polymer from the entire inner surface of the apparatus. The pre-cooled solvent is mixed in a predetermined ratio with the monomer (isoprene) in a special mixer and is fed by a dosing pump to the first apparatus of the polymerization battery. The technological scheme of the process is shown in Figure 2. The concentration of isoprene in solution is 16-18% by weight. A pre-prepared catalytic complex is continuously supplied to the same apparatus. The catalyst used is a titanium-based Ziegler-Natta catalyst. The formation of the catalytic complex proceeds at a high rate and releases 251.4 kJ/mol of heat. All components of the catalytic complex, namely, titanium tetrachloride (ТiCl4), triisobutylaluminum (TIBA), as well as modifiers diphenyl oxide (diproxide) are mixed in a certain ratio in a special mixer. Next, the mixture in the heat exchanger is brought to a temperature of 70 ºC and is fed by a dosing pump into the pipeline for the charge immediately before it is introduced into the polymerization battery. Hydrogen is supplied to the same pipeline at a dosage of 0.1 m3/t. The duration of the polymerization process is 2-6 hours, the conversion of isoprene can reach 95%. The schematic diagram of the polymerization stage of the isoprene rubber production process is shown in Figure 3.
P1, P2 - polymerizers.
Figure 3 - Schematic diagram of the polymerization stage
The final stages of the technological process are the deactivation of the catalyst, as well as the isolation of rubber from the solution by water degassing and drying of the rubber.
Architectures of remote access systems
Modern remote research and simulation systems are built on the principle of client-server architecture. This provides them with a number of advantages over file server applications. The client-server system is characterized by the presence of two interacting independent processes - the client and the server, which, in general, can be executed on different computers, exchanging data over the network. According to this scheme, data processing systems based on DBMS, mail and other systems can be built. We will talk, of course, about databases and systems based on them. And here it will be more convenient not just to consider the client-server architecture, but to compare it with another one - the file-server one.
In a file server system, data is stored on a file server (for example, Novell NetWare or Windows NT Server), and its processing is carried out at workstations, which, as a rule, operate one of the so-called "desktop DBMS" - Access, FoxPro , Paradox, etc.
The application on the workstation is "responsible for everything" - for the formation of the user interface, the logical processing of data and for the direct manipulation of data. The file server provides only the lowest level services - opening, closing and modifying files, I emphasize - files, not databases. The database exists only in the "brain" of the workstation.
Thus, several independent and inconsistent processes are engaged in the direct manipulation of data. In addition, to carry out any processing (search, modification, summation, etc.), all data must be transferred over the network from the server to the workstation (Figure 4).
Figure 4 - File-server model of the system
computer-aided learning system design
In the client-server system, there are (at least) two applications - the client and the server, which share between them the functions that in the file-server architecture are entirely performed by the application on the workstation. The database server, which can be Microsoft SQL Server, Oracle, Sybase, etc., is responsible for storing and directly manipulating data.
The user interface is built by the client, which can be built using a range of custom tools, as well as most desktop DBMSs. Data processing logic can be executed both on the client and on the server. The client sends requests to the server, usually formulated in SQL. The server processes these requests and sends the result to the client (of course, there can be many clients).
Thus, one process is engaged in the direct manipulation of data. At the same time, data processing takes place in the same place where the data is stored - on the server, which eliminates the need to transfer large amounts of data over the network (Figure 5)
Figure 5 - Client-server model of the system
What qualities does the client-server bring to the information system:
Reliability. The database server performs data modification based on the transaction mechanism, which gives any set of operations declared as a transaction the following properties:
atomicity - under any circumstances, all transactions of the transaction will either be performed, or none of them will be performed; data integrity at the end of the transaction;
independence - transactions initiated by different users do not interfere in each other's affairs;
· fault tolerance - after the completion of the transaction, its results will not be lost.
The transaction mechanism supported by the database server is much more efficient than that found in desktop DBMSs. the server centrally controls the operation of transactions. In addition, in a file-server system, a failure on any of the workstations can lead to data loss and inaccessibility to other workstations, while in a client-server system, a failure on the client almost never affects the integrity of the data and their availability for other clients.
Scalability is the ability of the system to adapt to the growth of the number of users and the size of the database with an adequate increase in the performance of the hardware platform, without replacing the software.
It is well known that the capabilities of desktop DBMS are seriously limited - these are five to seven users and 30-50 MB, respectively. The numbers represent some average values, in specific cases they can deviate both in one direction and in the other. Most importantly, these barriers cannot be overcome by increasing hardware capabilities.
Database server based systems can support thousands of users and hundreds of GB of information - just give them the right hardware platform.
Safety. The database server provides powerful data protection from unauthorized access that is not possible in desktop DBMS. At the same time, access rights are administered very flexibly - down to the level of table fields. In addition, it is possible to prohibit direct access to tables altogether, by performing user interaction with data through intermediate objects - views and stored procedures. So the administrator can be sure that no too smart user will read what he is not supposed to read.
Flexibility. There are three logical layers in a data application:
user interface;
logical processing rules (business rules);
Data management (do not confuse the logical layers with the physical layers, which will be discussed below).
As already mentioned, in a file-server architecture, all three layers are implemented in one monolithic application running on a workstation. Therefore, changes in any of the layers lead unequivocally to the modification of the application and the subsequent updating of its versions on workstations.
In a two-tier client-server application shown in Figure 1.4, as a rule, all user interface functions are implemented on the client, all data management functions are implemented on the server, but business rules can be implemented both on the server using server programming mechanisms (stored procedures, triggers, views, etc.) and on the client. In a three-tier application, a third, intermediate layer appears that implements business rules, which are the most frequently changed components of the application (Figure 6).
Figure 6 - Three-tier client-server model
The presence of not one, but several layers allows you to flexibly and cost-effectively adapt the application to changing requirements. If you need to make changes to the logic of the program, then:
1) In a file server system, we "simply" make changes to the application and update its versions on all workstations. But this "simple" entails maximum labor costs.
2) In a two-level client-server system, if the data processing algorithms are implemented on the server in the form of rules, it is executed by the business rules server, implemented, for example, as an OLE server, and we will update one of its objects without changing anything in client application, nor on the database server.
Thus, the client-server architecture is more promising and less costly to operate, however, the initial costs for its development are greater than when using the file-server architecture of the system. In addition, processing data on the server and transferring the results to the client is necessary condition for building remote systems.