Classification of basic processes and apparatuses of chemical technology

Depending from patterns Characterizing the flow, chemical technology processes are divided into five main groups.

1. Mechanical processes , the speed of which is related to the laws of solid state physics. These include: grinding, classification, dosing and mixing of solid bulk materials.

2. Hydromechanical processes , the flow rate of which is determined by the laws of hydromechanics. These include: compression and movement of gases, movement of liquids, solid materials, sedimentation, filtration, mixing in the liquid phase, fluidization, etc.

3. Thermal processes , the flow rate of which is determined by the laws of heat transfer. These include the following processes: heating, evaporation, cooling (natural and artificial), condensation and boiling.

4. Mass transfer (diffusion) processes , the intensity of which is determined by the rate of transition of a substance from one phase to another, i.e. laws of mass transfer. Diffusion processes include: absorption, rectification, extraction, crystallization, adsorption, drying, etc.

5. Chemical processes associated with the transformation of substances and changes in them chemical properties. The rate of these processes is determined by the laws of chemical kinetics.

In accordance with the listed division of processes, chemical apparatuses are classified as follows:

– grinding and classifying machines;

– hydromechanical, thermal, mass transfer devices;

– equipment for carrying out chemical transformations – reactors.

By organizational and technical structure processes are divided into periodic and continuous.

IN periodic process individual stages (operations) are carried out in one place (device, machine), but in different time(Fig. 1.1). IN continuous process (Fig. 1.2) individual stages are carried out simultaneously, but in different places (devices or machines).

Continuous processes have significant advantages over periodic processes, including the possibility of specializing equipment for each stage, improving product quality, stabilizing the process over time, ease of regulation, automation capabilities, etc.

When carrying out processes in any of the listed devices, the parameters of the processed materials change. The parameters characterizing the process are pressure, temperature, concentration, density, flow rate, enthalpy, etc.

Depending on the nature of the movement of flows and changes in the parameters of substances entering the device, all devices can be divided into three groups: devices ideal (full )mixing , devices ideal (full )repression and devices intermediate type .

It is most convenient to demonstrate the features of flows of various structures using the example of continuous heat exchangers of various designs. Figure 1.3a shows a diagram of a heat exchanger operating on the principle of ideal displacement. It is assumed that in this apparatus there is a “piston” flow of the flow without mixing. The temperature of one of the coolants changes along the length of the apparatus from the initial temperature to the final temperature as a result of the fact that subsequent volumes of liquid flowing through the apparatus do not mix with the previous ones, completely displacing them. The temperature of the second coolant is assumed to be constant (condensing steam).

In the device perfect mixing subsequent and previous volumes of liquid are ideally mixed, the temperature of the liquid in the apparatus is constant and equal to the final temperature (Fig. 1.3, b).

In real devices, neither the conditions of ideal mixing nor ideal displacement can be ensured. In practice, only a fairly close approximation to these circuits can be achieved, so real devices are intermediate type devices (Fig. 1.3, c).

Rice. 1.1. Apparatus for carrying out a periodic process:

1 – raw materials; 2 – finished product; 3 – steam; 4 – condensate; 5 – cooling water

Rice. 1.2. Apparatus for carrying out a continuous process:

1– heat exchanger-heater; 2 – apparatus with a stirrer; 3 – heat exchanger-refrigerator; I – raw materials; II – finished product; III – steam; IV – condensate;
V – cooling water

Rice. 1.3. Temperature changes when heating a liquid in devices of various types: a – complete displacement; b – complete mixing; c – intermediate type

The driving force of the liquid heating process under consideration for any element of the apparatus is the difference between the temperatures of the heating steam and the heated liquid.

The difference in the course of processes in each type of apparatus becomes especially clear if we consider how the driving force of the process changes in each type of apparatus. From a comparison of the graphs it follows that the maximum driving force occurs in complete displacement devices, the minimum in complete mixing devices.

It should be noted that the driving force of processes in continuously operating ideal mixing apparatus can be significantly increased by dividing the working volume of the apparatus into a number of sections.

If the volume of an ideal mixing apparatus is divided into n apparatuses and the process is carried out in them, then the driving force will increase (Fig. 1.4).

With an increase in the number of sections in ideal mixing apparatuses, the value of the driving force approaches its value in ideal displacement apparatuses, and with a large number of sections (about 8–12), the driving forces in apparatuses of both types become approximately the same.

Rice. 1.4. Changing the driving force of the process during partitioning

Modern chemical technology is associated with grinding, crushing, and transportation of various materials. Some of them are converted into aerosol form during processing; the resulting dust, along with ventilation and process gases, enters the atmosphere. Let's consider the basics of chemical technology currently used in production.

Devices for cleaning dust from gaseous substances

Dust particles have a high total surface area, as a result they exhibit increased biological and chemical activity. Some substances in aerodispersed form acquire new properties; for example, they are capable of spontaneous explosion. There are various chemical technology devices used to purify gaseous substances generated in production from dust particles of various sizes and shapes.

Despite significant differences in design, the principle of their operation is based on the delay of the weighted phase.

Cyclone and dust settling chambers

Analyzing various processes and devices of chemical technology, we will focus on the group of dust collecting devices, which include:

• rotary dust collectors;
• cyclones;
• louver models;
• dust settling chambers.

Among the advantages of such devices, we note the simplicity of their design, due to which they are produced at non-specialized enterprises.

As a disadvantage of such devices, professionals note insufficient efficiency and the need for repeated cleaning. All types of dust collecting devices operate on the basis of centrifugal forces and differ in the power and speed of deposition of dust particles.

For example, the classical chemical technology for the production of sulfuric acid involves the use of a cyclone to remove impurities from the furnace gas formed during the roasting of pyrite. Gas, which contains particles of cinder (mixed iron oxide), enters the cyclone through a special tangential pipe, then rotates along the inner walls of the apparatus. The accumulation and deposition of dust is carried out in a dust collection hopper, and the purified gas rises upward and goes to the next apparatus through the central pipe.

Chemical technology is associated with the use of a cyclone in cases where high demands are not placed on the resulting gaseous substance.

Wet cleaning devices

The wet method in modern production is considered one of the most effective and simple types purification of industrial gases from various suspended particles. Chemical technology processes and apparatus associated with wet gas purification are currently in demand not only in domestic but also in foreign industry. In addition to suspended particles, they are capable of capturing gaseous and vaporous components that reduce the quality of products.

There is a division of such devices into packed hollow, foam and bubbling, turbulent and centrifugal types.

The disintegrator consists of a rotor and a stator equipped with special guide vanes. The liquid is fed into the rotating rotor through nozzles. Thanks to the gas flow moving between the stator and rotor rings, it is crushed into separate drops, resulting in increased contact of gases with captured liquid particles. Thanks to centrifugal forces, the dust is thrown to the walls of the apparatus, then removed from it, and the purified gaseous substances enter the next apparatus or are released into the atmosphere.

Porous filters

Chemical technology often involves filtering substances through special porous partitions. This method involves a high degree of purification from various suspended particles, which is why porous filters are in demand in chemical production.

Their main disadvantages are the need for systematic replacement of filter components, as well as the large dimensions of the devices.

Industrial filters are divided into granular and fabric classes. They are designed for purification of industrial gaseous substances with a high concentration of dispersed phase. To periodically remove accumulated particles, special regenerating devices are installed in the devices.

Features of oil refining

Fine chemical technologies associated with the purification of petroleum products from mechanical impurities and high humidity are based precisely on filtration processes.

Among the processes and devices that are currently used in the petrochemical industry are filtration through coalescing partitions and ultrasound. With the help of centrifugal separators, coalescent filters, settling systems, a preliminary stage of purification is carried out.

In order to carry out complex purification of petroleum products, porous polymer compositions are currently used as

They have confirmed their effectiveness, strength, and reliability, which is why they are increasingly used in general chemical technology.

Electrical filters

The technology for producing sulfuric acid involves the use of this particular apparatus. Their cleaning efficiency ranges from 90 to 99.9 percent. Electrostatic precipitators are capable of trapping liquid and solid particles of different sizes; the devices operate in the temperature range of 400-5000 degrees Celsius.

Due to their low operating costs, these devices have become widespread in modern chemical production. Among the main disadvantages characteristic of such equipment, we highlight the significant initial costs of their construction, as well as the need to allocate a large space for installation.

WITH economic point In view of this, it is advisable to use them when cleaning significant volumes, otherwise the use of electric precipitators will be a costly undertaking.

Contact device

Chemistry and chemical technology involves the use of a variety of apparatus and devices. An invention such as a contact apparatus is intended to carry out catalytic processes. An example is the oxidation of sulfur oxide (4) into sulfur dioxide, which is one of the stages technological production sulfuric acid.

Thanks to the radial-spiral year, the gas passes through a layer with a catalyst located on special partitions. Thanks to the contact apparatus, the efficiency of catalytic oxidation significantly increases and the maintenance of the device is simplified.

A special removable basket with a protective layer of the catalyst allows you to replace it without any problems.

Kiln

This apparatus is used in the production of sulfuric acid from The chemical reaction takes place at a temperature of 700 °C. Thanks to the counter-flow principle, which involves feeding into opposite directions oxygen of the air and iron pyrites, a so-called fluidized layer is formed. The bottom line is that the mineral particles are distributed evenly throughout the oxygen volume, which guarantees a high-quality oxidation process.

After the oxidation process is completed, the resulting “cinder” (iron oxide) falls into a special hopper, from which it is periodically removed. The resulting furnace gas (sulfur oxide 4) is sent for dust removal and then dried.

Modern kilns used in chemical production can significantly reduce the loss of reaction products, while simultaneously increasing the quality of the resulting furnace gas.

In order to speed up the oxidation process of pyrite in the kiln, in the production of sulfuric acid, the feedstock is pre-crushed.

Shaft furnaces

Such reactors include blast furnaces, which form the basis of ferrous metallurgy. The charge enters the furnace, comes into contact with oxygen supplied through special holes, and then the resulting cast iron is cooled.

Various modifications of such devices have found their application in the processing of not only iron but also copper ores and the processing of calcium compounds.

Conclusion

It's hard to imagine a full life modern man without the use of a chemical product. The chemical industry, in turn, cannot fully operate without the use of automated and mechanical technologies and the use of special equipment. Currently, chemical production is a complex set of equipment and machines that are designed for chemical-physical and chemical processes, automated equipment for packaging and transportation of finished products.

Among the main machines and devices in demand in such production, there are those that allow increasing the working surface of the process, carrying out high-quality filtration, full heat exchange, increasing the yield of reaction products, and reducing energy costs.

Preface.

The discipline “Processes and Apparatuses of Chemical Technology” (PACT) is one of the fundamental general engineering disciplines. It is final in a student’s general engineering training and fundamental in special training.

The technology for producing a variety of chemical products and materials includes a number of similar physical and physicochemical processes characterized by general laws. These processes in various industries are carried out in devices similar in operating principle. Processes and apparatuses common to different branches of the chemical industry are called basic processes and apparatuses of chemical technology.

The PACT discipline consists of two parts:

· theoretical foundations of chemical technology;

· standard processes and apparatuses of chemical technology;

The first part outlines the general theoretical principles of typical processes; fundamentals of the methodology of approach to solving theoretical and applied problems; analysis of the mechanism of the main processes and identification general patterns their course; generalized methods of physical and mathematical modeling and calculation of processes and apparatus are formulated.

The second part consists of three main sections, the content of which reveals applied engineering issues of the fundamentals of chemical technology:

· hydromechanical processes and devices;

· thermal processes and devices;

· mass transfer processes and apparatus.

These sections provide theoretical justification for each typical technological process, discuss the basic designs of devices and the methodology for their calculation. Lectures, laboratory and practical classes, course design, independent work of students and general engineering production practice ensure the acquisition of knowledge, skills and abilities necessary both for further education and for work in production.

Introduction.

1.1 Subjects and objectives of the course.

Technology (techne-art, craftsmanship) is a set of methods of processing, manufacturing, changing the state, properties, form of raw materials, materials or semi-finished products during the production process.

Studying technological processes constitutes the subject course. Technology, as a science, determines the conditions for the practical application of laws natural sciences(physics, chemistry, mechanics, etc.) for the most efficient implementation of various technological processes. Technology is directly related to production, and production is constantly in a state of change and development.

The main objective of the course: identifying general patterns of processes of transfer and preservation of various substances; development of methods for calculating technological processes and devices for their implementation; familiarization with the designs of devices and machines, their characteristics.

As a result of mastering the discipline, students should know:

1. Theoretical foundations of chemical technology processes; laws; describing them; physical essence of processes, installation diagrams; designs of devices and principles of their operation; methods for calculating processes and devices, including using a computer.

2. Principles of modeling and large-scale transition, correct selection of equipment for carrying out relevant processes and the possibility of their intensification.

3. Modern achievements of science and technology in the field of chemical technology.

Skills that students must master:

1. Correctly apply theoretical knowledge when solving specific problems of informed choice:

a) designs of apparatus for carrying out certain processes;

b) operating parameters of the devices;

c) process flow diagrams.

2. Carry out calculations of devices independently.

3. Work independently on laboratory research facilities, process experimental data, obtain empirical dependencies, analyze calculation methods.

4. Design standard processes and devices, use technical literature and GOSTs, fill out technical documentation in accordance with the ESKD.

1.2 Classification of the main processes of chemical technology.

Modern chemical technology studies the processes of production of various acids, alkalis, salts, mineral fertilizers, petroleum and coal products, organic compounds, polymers, etc. However, despite the huge variety of chemical products, their production is associated with a number of similar processes (moving liquids and gases, heating and cooling, drying, chemical interaction, etc.). So, depending on the laws that determine the speed of processes, they can be combined into the following groups:

1. Hydromechanical processes, the speed of which is determined by the laws of hydromechanics. This includes the transportation of liquids and gases, the production and separation of heterogeneous systems, etc.

2. Thermal processes, the speed of which is determined by the laws of heat transfer (cooling and heating of liquids and gases, condensation of vapors, boiling of liquids, etc.).

3. Mass transfer processes, the rate of which is determined by the laws of mass transfer from one phase to another through the interface (absorption, adsorption, extraction, distillation of liquids, drying, etc.)

4. Chemical processes, the speed of which is determined by the laws of chemical kinetics.

5. Mechanical processes that are described by the laws of mechanics solids(grinding, sorting, mixing solid materials, etc.).

The listed processes form the basis of most chemical production and are therefore called the basic (standard) processes of chemical technology.

PACT studies the first three groups, the fourth group studies the discipline of OCT, the fifth group studies the subject of special disciplines of the major departments.

Depending on whether the process parameters (flow rates, temperature, pressure, etc.) change or do not change over time, they are divided into stationary(steady) and non-stationary(unstable). If we denote any parameter by U, Then:

Stationary process U(x,y,z)

Unsteady process U(x,y,z,t)

Batch process characterized by the unity of the location of its individual stages. The process is non-stationary.

Continuous process characterized by the unity of time during all its stages. The process is steady (stationary).

Meet combined processes - some stages are carried out continuously, some periodically.

However, the PACT course is not structured as a presentation of the individual groups listed above. The general theoretical foundations of chemical technology are studied separately, and then typical processes and apparatuses of chemical technology are outlined.

1.3 Medium continuity hypothesis.

A liquid medium fills a particular volume without any free spaces, in a continuous manner, or is a continuous medium. When describing such media, it is assumed that they consist of particles. Moreover, by a particle of a continuous medium we mean not any arbitrarily small part of its volume, but a very small part of it, containing billions of molecules inside it. In general, the minimum cost of dividing the macroscopic scale of the spatial Δl or temporal Δt coordinate should be small enough to neglect the change in macroscopic physical quantities within Δl or Δt, and large enough to neglect fluctuations of microscopic quantities obtained by averaging these quantities over time Δt or particle volume Δl 3. The choice of the minimum division price of the macroscopic scale is determined by the nature of the problem being solved.

The movement of macroscopic volumes of the medium leads to the transfer of mass, momentum and energy.

LITERATURE 1. Kasatkin A. G. Basic processes and apparatus of chemical technology. Ed. 9th, M.: Chemistry. 1973 – 754 p. 2. Planovsky A. N., Nikolaev P. I. Basic processes and apparatus of chemical and petrochemical technology. Ed. 2nd, M.: Chemistry. 1972 – 493 p. 3. Basic processes and apparatus of chemical technology: A manual for design / G. S. Borisov, V. P. Brykov, Yu. I. Dytnersky and others. Ed. Yu. I. Dytnersky. Ed. 2nd, M.: Chemistry. 1991 – 496 p. 4. Aksartov M. M. Basic processes and apparatus of chemical technology. Lecture course. Publ. Kar. GI in 1-2 tons.

General principles analysis and calculation of processes and apparatuses I. General information 1. Subject of the course "Processes and apparatuses" 2. The emergence and development of the science of processes and apparatuses 3. Classification of basic processes 4. General principles of analysis and calculation of processes and apparatuses 5. Various systems of units of measurement of physical quantities

Classification of basic processes n n n Hydromechanical processes, the speed of which is determined by the laws of hydrodynamics - the science of the movement of liquids and gases. Thermal processes occurring at a speed determined by the laws of heat transfer - the science of methods of heat distribution. Mass transfer (diffusion) processes, characterized by the transfer of one or more Chemical (reaction) processes that occur at a rate determined by the laws of chemical kinetics. components of the initial mixture from one phase to another through the phase interface. Mechanical processes described by the laws of solid mechanics.

According to the method of organization, processes are divided into: 1. 2. 3. Periodic processes are carried out in devices into which raw materials are loaded at certain intervals; After their processing, the final products are unloaded from these devices. Continuous processes are carried out in flow-through devices. Combined processes. These include continuous processes, individual stages of which are carried out periodically, or periodic processes, one or more stages of which occur continuously.

According to the distribution of residence times, they are distinguished: 1. 2. 3. 4. In ideal displacement apparatuses, all particles move in a given direction; without mixing with particles moving in front and behind and completely displacing the particles in front of the flow. In ideal mixing apparatuses, incoming particles are immediately completely mixed with the particles located there, i.e., they are evenly distributed throughout the volume of the apparatus. Real continuously operating devices are devices of an intermediate type. Processes can also be classified depending on the change in their parameters (speeds, temperatures, concentrations, etc.) over time. On this basis, processes are divided into established (stationary) and non-steady (non-stationary, or transient).

Hydromechanical processes. II. Basics of hydraulics. General questions of applied hydraulics in chemical equipment 1. Basic definitions 2. Some physical properties of liquids A. Hydrostatics 3. Euler's differential equilibrium equations 4. Basic equation of hydrostatics 5. Some practical applications of the basic equation of hydrostatics

n Newton's law of internal friction Surface tension is expressed in the following units: in the SI system [ν] = [j/m 2] = [n m/m] = [n/m] in the CGS system ] = erg/cm 2] = [din/cm 2] in the MKGSS system] = kgf m/m 2] = kgf/m]

For each point of a fluid at rest, the sum of the leveling height and piezometric pressure is a constant value. (II, 18) (II, 18 d) n The last equation is an expression of Pascal’s law, according to which the pressure created at any point of a resting incompressible fluid is transmitted equally to all points of its volume.

Some practical applications of the basic equation of hydrostatics Equilibrium conditions in communicating vessels: Fig. II-4. Conditions for equilibrium in communicating vessels: a – homogeneous liquid; b – dissimilar (immiscible) liquids

In open or closed communicating vessels under the same pressure, filled with a homogeneous liquid, its levels are located at the same height, regardless of the shape and cross-section of the vessels

Rice. II-5. To determine the height of the hydraulic seal in a continuously operating liquid separator Fig. II-6. Pneumatic Liquid Level Meter

HYDROMECHANICAL PROCESSES. B. Hydrodynamics 1. Basic characteristics of the movement of fluids 2. Equation of continuity (continuity) of flow 3. Euler's differential equations of motion 4. Navier-Stokes differential equations of motion 5. Bernoulli's equation 6. Some practical applications of Bernoulli's equation 7. Motion of bodies in liquids 8. Movement of liquids through stationary granular and porous layers 9. Hydrodynamics of boiling (fluidized) granular layers 10. Elements of hydrodynamics of two-phase flows 11. Structure of flows and distribution of residence time of liquid in apparatus

Hydraulic radius Hydraulic radius r (m) is understood as the ratio of the area of ​​the flooded section of a pipeline or channel through which liquid flows, i.e., the live cross-section of the flow, to the wetted perimeter: (II, 26)

The equivalent diameter is equal to the diameter of a hypothetical circular pipeline for which the ratio of area S to wetted perimeter P is the same as for a given non-circular pipeline.

Steady and unsteady flows. The movement of a liquid is steady, or stationary, if the speeds of the particles of the flow, as well as all other factors influencing its movement (density, temperature, pressure, etc.), do not change in time at each fixed point in space through which the liquid passes. Under these conditions, for each flow section, the fluid flow rate is constant over time.

Modes of fluid movement. n n The movement in which all the particles of the liquid move along parallel trajectories is called stream or laminar. Disordered motion, in which individual particles of a fluid move along intricate, chaotic trajectories, while the entire mass of the fluid as a whole moves in one direction, is called turbulent.

Reynolds criterion (Re) n The Re criterion is a measure of the relationship between viscous and inertial forces in a moving flow.

Stokes' law The equation is Stokes's law, expressing the parabolic distribution of velocities in a cross-section of a pipeline during laminar motion.

Poiseuille's equation n With laminar flow in a pipe, the average velocity of the fluid is equal to half the speed along the axis of the pipe.

Turbulent viscosity n Turbulent viscosity, unlike ordinary viscosity, is not a physicochemical constant determined by the nature of the liquid, its temperature and pressure, but depends on the speed of the liquid and other parameters that determine the degree of turbulence of the flow (in particular, the distance from the pipe wall and etc.).

Differential equation flow continuity for unsteady motion of a compressible fluid. Differential continuity equation for incompressible fluid flow.

Equation of constant flow n These expressions represent the equation of continuity (density) of flow in its integral form for steady motion. This equation is also called the constant flow equation or material flow balance. 1 w 1 S 1 = 2 w 2 S 2 = 3 w 3 S 3 M 1 = M 2 = M 3 n The velocities of the dropping liquid in various cross sections of the pipeline are inversely proportional to the areas of these sections. w 1 S 1 = w 2 S 2 = w 3 S 3 = const Q 1 = Q 2 = Q 3

Euler's differential equations of motion n System of equations (II, 46) taking into account expressions (II, 47) represents the differential equations of motion of an ideal Euler fluid for a steady flow. (II, 46) (II, 47)

Bernoulli's equation n n Bernoulli's equation for an ideal fluid The quantity is called the total hydrodynamic head, or simply the hydrodynamic head.

Consequently, according to Bernoulli's equation, for all cross sections of a steady flow of an ideal fluid, the hydrodynamic pressure remains unchanged. z - leveling height, also called geometric, or altitude, pressure (hg), represents the specific potential energy of the position at a given point (given section); – pressure pressure (hpress), or piezometric pressure, characterizes the specific potential energy of pressure at a given point (given section). The sum z+, called the total hydrostatic, or simply static head (hst), therefore expresses the total specific potential energy at a given point (a given section).

Bernoulli's equation n n Thus, according to the Bernoulli equation, during steady motion of an ideal fluid, the sum of the velocity and static pressure, equal to the hydrodynamic pressure, does not change when moving from one cross section of the flow to another. Thus, the Bernoulli equation is a special case of the law of conservation of energy and expresses the energy balance of the flow.

MOVEMENT OF LIQUIDS n 1. 2. 3. 4. 5. Movement of liquids Displacement pumps Design of positive displacement pumps Centrifugal pumps Design of centrifugal pumps Other types of pumps. Siphons

MOVEMENT OF LIQUIDS Depending on the operating principle of the pump, an increase in the energy and pressure of the liquid can be carried out: 1. in volumetric pumps - by displacing liquid from the closed space of the pump with bodies moving back and forth or rotating; 2. in vane or centrifugal pumps - the centrifugal force that arises in the liquid when the vane wheels rotate; 3. in vortex pumps - intensive formation and destruction of vortices that arise during rotation of the impellers; 4. in jet pumps - a moving stream of air, steam or water; 5. in gas lifts - the formation of foam when air or gas is supplied to the liquid; 6. in monteju and siphons - pressure of air, gas or steam on the liquid.

Rice. III-8. Valve designs. I – ball valve. 1 - body; 2 – valve; 3 – cover. II – flap valve. 1 – cover; 2 – saddle.

Diaphragm (diaphragm) pumps Fig. III-9. Diaphragm pump: 1 – housing; 2 – valves; 3 – cylinder; 4 – plunger; 5 – diaphragm (membrane).

Centrifugal pumps III-13 Fig. III-13. Diagram of a centrifugal pump: 1 – inlet valve; 2 - suction pipeline; 3 – impeller; 4 – shaft; 5 – body; 6 – valve; 7 – check valve; 8 – discharge pipeline.

Types of seals n n I – seal with a hydraulic seal: 1 – lantern; 2 – oil seal. II – gland for acids: 1, 2 – annular cavities; 3, 4 – outlet holes. III – spring seal: 1 – gasket; 2 – spring.

Sealless pump n 1 housing, 2 – cover, 3 – impeller, 4 – housing sleeve, 5 – shaped sleeve, 6 – sleeve, 7 – left disk, 8 – pin, 9 – right disk, 10 – tie rod, 11 – spring, 12 – shaft, 13, 14 – rings.

Montaju. Rice. III-8. Montage: 1 – filling pipe; 2, 3, 4, 5, 8 – taps; 6 – pressure gauge; 7 – pipes for pressing

Jet pumps. Steam pump. Rice. III-22. Steam pump. 1 – steam fitting; 2 – steam nozzle; 3 – mixing nozzle; 4 - suction chamber; 5 – suction fitting; 6 - diffuser; 7 – discharge fitting; 8 – condensate fitting; 9, 10 - check valves.

Water jet pump. III-22 Fig. III-22. Water jet pump. 1 – nozzle; 2 – hole; 3 – suction pipeline; 4 1 – nozzle; 2 – hole; 3 – suction fitting pipeline; 4 - fitting III-23

Air lift diagram Fig. III-24. Air lift diagram: 1, 2 – pipes; 3 – mixer; 4 - separator Fig. III-24

Air lifts (airlifts) and siphons Fig. III-25. Air lift systems 1 – air pipe; 2 – supply pipe for the mixture; 3 – mixer. Rice. III- 26. Siphons. 1 – reservoir; 2 – siphon pipe; 3, 4, 5 – taps, 6 – inspection channel

Movement and compression of gases (compressor machines) n n n n 1. General information 2. Piston compressors 3. Rotary compressors and gas blowers 4. Centrifugal machines 5. Axial fans and compressors 6. Screw compressors 7. Vacuum pumps 8. Comparison and applications of compressor machines various types

MOVEMENT AND COMPRESSION OF GASES (COMPRESSOR MACHINES) n n n n General information Machines designed to move and compress gases are called compressor machines. Depending on the degree of compression, the following types of compressor machines are distinguished: fans (3. 0) - to create high pressures; vacuum pumps - for suction of gases at pressure below atmospheric.

Piston compressors n Single-stage horizontal single-acting compressor Fig. IV-1. Schemes of single-stage piston compressors: a – single-cylinder, single-acting; b – single-cylinder, double-acting; c – two-cylinder single action. 1 = cylinder; 2 – piston; 3 – suction valve; 4 – discharge valve; 5 – connecting rod; 6 – crank; 7 – flywheel; 8 – slider (crosshead)

Multi-stage compression. Rice. IV-2. Schemes of multi-stage piston compressors. a, b, c – with compression stages in separate cylinders (a – simultaneous design; b – double-row design; c – with a V-shaped arrangement of cylinders); d – with a differential piston: 1 – cylinder; 2 – piston; 3 – suction valve; 4 – discharge valve; 5 – connecting rod; 6 – slider (crosshead); 7 – crank; 8 – flywheel; 9 – intermediate refrigerator.

Turbo gas blowers. Rice. IV-8. Scheme of a multi-stage turbo-gas blower. 1 – body; 2 – impeller; 3 – guide vane; 4 – check valve. Rice. IV-9. Entropy diagram of gas compression in a turbo-gas blower

Separation of inhomogeneous systems V. Separation of inhomogeneous systems 1. Heterogeneous systems and methods of their separation 2. Separation of liquid systems 2. Material balance of the separation process A. Settlement 3. Rate of constrained sedimentation (sedimentation) 4. Settling tanks B. Filtration 5. General information 6. Filter partitions 7. Filter arrangement

Continuous settling tank Fig. IV-3. Continuous settling tank with a rake mixer 1 – housing; 2 – annular groove; 3 - stirrer; 4 – blades with paddles; 5 – pipe for supplying the initial suspension; 6 – fitting for removing clarified liquid; 7 – unloading device for sediment (sludge); 8 – electric motor.

Rice. V-6. Continuous settling tank with conical shelves; 1 – fitting for supplying the separated suspension; 2 – conical shelves; 3 – fitting for draining sludge; 4 – channels for draining clarified liquid; 5 – fitting for removing clarified liquid

Rice. V-7. Continuous sedimentation tank for separating suspensions. 1 – fitting for supplying emulsions; 2 – perforated partition; 3 – pipeline for light phase removal; 4 – pipeline for removal of heavy phase; 5 device for breaking the siphon.

B. FILTERING Fig. V-8. Diagram of the filtration process. 1 – filter; 2 – filter partition; 3 suspension; 5 sediment

Filter arrangement Fig. V-10. Nutsch operating under pressure up to 3 atm. 1 – body; 2 – turbine; 3 - removable cover; 4 – filter bottom; 5 – filter partition; 6 – supporting partition; 7 – protective mesh; 8 – annular partition; 9 – fitting for supplying suspension; 10 – fitting for compressed air supply; 11 – fitting for removing filtrate; 12 – safety valve

Drum filters. Rice. V-13. Diagram of the operation of a drum vacuum filter with an external filtration surface. 1 – drum; 2 – connecting tube; 3 – switchgear; 4 – reservoir for suspension; 5 – swinging mixer; 6, 8 - cavities of the distribution device; 7 – spraying device; 9 – endless tape; 10 – guide roller; 11, 13 – cavities of the distribution device communicating with a source of compressed air; 12 – knife for removing sediment.

B. Centrifugation D. Separation of gas systems (gas purification) VI. Mixing in liquid media B. Centrifugation 1. Basic principles 2. Design of centrifuges D. Separation of gas systems (gas purification) 1. General information 2. Gravity purification of gases 3. Purification of gases under the action of inertial and centrifugal forces 4. Purification of gases by filtration 5. Wet gas purification 6. Electric gas purification VI. Mixing in liquid media 1. General information 2. Mechanical mixing 3. Mechanical mixing devices

Design of centrifuges n Three-column centrifuges. Rice. V-14. Three-column centrifuge. 1 – perforated rotor; 2 – support cone; 3 – lag; 4 – bottom of the frame; 5 fixed casing; 6 – casing cover; 7 – bed; 8 – traction; 9 – column; 10 – hand brake.

Hanging centrifuges. Rice. V-15. Suspended centrifuge. 1 - pipeline for supplying suspension; 2 – rotor with solid walls; 3 – shaft; 4 – fixed casing; , 5 fitting for removing liquid; 6 – conical cover; 7 – connecting ribs

Horizontal centrifuges with a knife device for removing sediment. Rice. V-16. Horizontal centrifuge with a knife device for removing sediment. 1 – perforated rotor; 2 – pipe for supplying suspension; 3 – casing; 4 – fitting for removing centrate; 5 – knife; 6 – hydraulic cylinder for lifting the knife; 7 inclined chute; 8 – channel for removing sediment

Centrifuges with a pulsating piston for discharging sediment. Rice. V-17. Centrifuge with pulsating piston for discharge of sediment. 1 – pipe for the supply of suspension; 2 conical funnel; 3 – perforated rotor; 4 – metal slotted sieve; 5 – piston; 6 – fitting for removing centrate; 7 – channel for sediment removal; 8 – rod; 9 – hollow shaft; 10 – disk moving back and forth

Centrifuges with a screw device for unloading sediment. Rice. V-18. Centrifuge with a screw device for unloading sediment. 1 – outer pipe; 2, 4 – hole for the passage of suspension; 3 – inner pipe; 5 – conical rotor with solid walls; 6 – cylindrical base of the auger; 7 – auger; 8 – casing; 9 – hollow pins; 10 – holes for sediment passage; 11 – chamber for sediment; 12 – hole for passage of centrate; 13 – chamber for centrate.

Centrifuges with inertial sediment discharge. Rice. V-19. Centrifuge with inertial sediment discharge. 1 – funnel for the suspension; 2 – rotor; 3 – channel for removing the liquid phase; 4 – channel for removing solid phase; 6 – auger.

Liquid separators. Rice. V-20. Disc type liquid separator. 1 – pipe for supplying emulsion; 2 – plates; 3 – hole for draining heavier liquid; 4 – holes for draining lighter liquid; 5 – ribs.

1. 2. 3. 4. 5. SEPARATION OF GAS SYSTEMS (GASE CLEANING) The following methods of gas purification are distinguished: sedimentation under the influence of gravity (gravity purification); sedimentation under the influence of inertial, in particular centrifugal forces; filtration; wet cleaning; deposition under the influence of electrostatic forces (electric

Gravity purification of gases Dust settling chambers. Rice. V-21. Dust settling chamber. 1 – camera; 2 – horizontal partitions (shelves); 3 reflective partition; 4 – doors.

Gas purification under the influence of inertial and centrifugal forces. Inertial dust collectors. Rice. V-22. Inertial louvered dust collector. 1 – primary louvered dust collector; 2 – cyclone; 3 – pipes for purified gas; 5 – dust removal pipe.

Cyclone Fig. V-23. Cyclone designed by NIIOgaz. 1 – body; 2 – conical bottom; 3 – cover: 4 – inlet pipe; 5 – dust collector; 6 - exhaust pipe.

Battery cyclone V-24. V-25. Rice. V-26. Element of a direct-flow battery cyclone. 1 – twisting device; 2 inlet pipe; 3 – annular slot gap; 4 – exhaust pipe.

Gas purification by filtration Depending on the type of filter partition, the following gas filters are distinguished: a) with flexible porous partitions made of natural, synthetic and mineral fibers (fabric materials), non-woven fibrous materials (felt, cardboard, etc.), porous sheet materials (sponge rubber, polyurethane foam, etc.), metal fabrics; b) with semi-rigid porous partitions (layers of fibers, shavings, meshes); c) with rigid porous partitions made of granular materials (porous ceramics, plastics, sintered or pressed metal powders, etc.); d) with granular layers of coke, gravel, quartz sand, etc.

Filters with flexible porous partitions. Rice. V-27. Bag filter with mechanical shaking and backwashing of the fabric. I-IV – filter sections; 1, 9 – fans; 2 – inlet gas duct; 3 – camera; 4 – sleeves; 5 – distribution grid; 6, 8 – throttle valves; 7 – exhaust pipe; 10 – shaking mechanism; 11 – frame; 12 – auger; 13 – sluice gate.

Filters with rigid porous partitions Ceramic-metal filter Fig. V-28. Metal-ceramic filter. 1 – body; 2 – metal sleeves; 3 – grid; 4 - inlet fitting; 5 – outlet fitting; 6 – compressed air manifold; 7 – bunker.

Filters with granular layers. Rice. V-29. Continuous filter with a moving layer of granular filter material. 1 – body; 2 – filter partition; 3 – filter material; 4 inlet fitting; 5 – outlet fitting; 6 – gates; 7 – feeders.

V-34

MIXING IN LIQUID MEDIA Methods of mixing. Regardless of what medium is mixed with a liquid - gas, liquid or solid granular substance - there are two main methods of mixing in liquid media: mechanical (using mixers of various designs) and pneumatic (compressed air or inert gas). In addition, mixing in pipelines and mixing using nozzles and pumps are used.

Preface
Introduction
1. Subject of chemical technology and course objectives
2. Classification of processes
3. Material and energy calculations
General concepts about material balance. Exit. Performance. Intensity production processes. Energy balance. Power and efficiency.
4. Dimension of physical quantities
PART ONE. HYDRODYNAMIC PROCESSES
Chapter first. Basics of hydraulics
A. Hydrostatics)