REPUBLIC OF KAZAKHSTAN
INNOVATIVE EURASIAN UNIVERSITY
FOOD PRODUCTION EQUIPMENT
PRODUCTS
BACKGROUND LECTURE NOTES
PAVLODAR 2012
THEMATIC PLAN OF LECTURES
| № | Lecture topics | Number of hours |
| Module 1 | ||
| Lecture 1. Introduction. Food transport equipment | ||
| Lecture 2. Sorting and calibration equipment | ||
| Lecture 3. Washing equipment | ||
| Lecture 4. Machines for grinding food | ||
| Lecture 5. Machines for mixing products | ||
| Lecture 6. Cleaning equipment | ||
| Lecture 7. Equipment for separating inhomogeneous bodies | ||
| Lecture 8. Machines for processing products by pressure | ||
| Lecture 9. Filters used in the processing industry | ||
| Lecture 10. Thermal equipment | ||
| Lecture 11. Frying and baking equipment | ||
| Lecture 12. Evaporation equipment | ||
| Lecture 13. Equipment for drying processed raw materials | ||
| Lecture 14. Equipment for packaging and packaging of food products | ||
| Lecture 15. Equipment for measuring food products by weight and volume | ||
| Total: |
Lecture 1. Introduction. Equipment for transporting food products.
Lecture outline:
1. Objectives of the course and its content.
2. Classification of technological equipment.
3. Overhead tracks, conveyors and equipment for their maintenance.
4. Devices for transferring products through pipes.
1. This course is based on the knowledge acquired in the study of general engineering and special disciplines: heat engineering, hydraulics, food production processes and apparatus, general food production technology, etc.
The discipline is one of the special disciplines of the educational process at a university and forms students' knowledge about equipment for machining.
The objectives of the discipline include:
Study of the physical essence and mechanism of phenomena accompanying food processing processes;
Study of the design forms of working parts of technological equipment;
Studying the fundamental principles of the designs of modern technological machines and devices;
Studying ways to intensify and mechanize production processes.
The course content includes studying the types of technological equipment for machining. Structural forms of technological equipment. Types of technological flows, processes and operations. Classification of modern technological equipment for the food industry. Basic requirements for technological equipment and its working parts.
2. Equipment for mechanical processing is usually classified into:
Washing of raw materials (grain, sugar beets, fruits and vegetables, animal carcasses) and containers;
Cleaning and separating grain (scalpers and destoners, air-sieve separators and sifters, triremes, paddy machines, air and magnetic separators, etc.);
Inspection, calibration and sorting of fruits and vegetables (inspection conveyors, calibrating and sorting machines, etc.);
Cleaning plant and animal raw materials from the outer cover (waisting and brushing machines, machines for peeling and grinding grain crops, whippers, comb separators, machines for peeling potatoes and root crops, machines for separating husks and stalks, rubbing machines, machines for skinning animals and for removing feathers from birds, etc.);
Grinding of food raw materials (roller machines, crushers, mills, cutting machines and beet slicers, flattening machines, meat grinders, grinders and cutters, homogenizers, etc.);
Sorting and enrichment of bulk products, grinding of food raw materials (sifters and sieve machines, grinding machines and vibrating centrifugals, entolsitors and detachers, crushing and screening machines, etc.);
Separation of liquid heterogeneous food media (settlers, centrifuges, separators, filters and filtering devices, membrane modules and devices, oil producers and oil formers, presses, etc.);
Mixing food media (mixers for liquid food media, kneading machines for highly viscous food media, machines and apparatus for the formation of foamy masses, mixers for bulk food media, etc.);
Forming of food media (extruders, machines for molding by stamping, casting, jigging and pressing, machines for cutting layers and blanks from semi-finished products, etc.).
3. Overhead tracks are a means of organizing the technological flow and are intended for the transfer of products, both during its processing, and for inter-shop transportation of bulk cargo.
Suspended tracks are usually classified according to a number of the most important characteristics:
1) according to the presence of traction, they are either with mechanical traction - conveyor belts (conveyors) or without mechanical traction - non-conveyor type.
2) by location - planar (horizontal, vertical, inclined) and spatial.
3) by type of traction organ - chain, rope, auger and rod.
4) by the type of movement - with continuous and rhythmically pulsating movement of the traction organ and load (i.e. movement with periodic stops).
5) according to the design of load-carrying bodies - with removable trolleys (trolleys) and hooks; with permanently attached hooks.
6) according to the type of transmission of motion from the conveyor chain to the load - pushing and load-carrying.
7) by type of drive - with electric, hydraulic and pneumatic drive.
8) by the number of drives - single-drive, multi-drive and with group drive.
9) by purpose - simple overhead tracks (conveyors) for processing one type of livestock; universal conveyors for processing several types of livestock (Zakharov conveyor).
4. To transfer products such as fat, blood, broth, mainly rotary pumps such as gear, eccentric vane, rotary piston, hose, rotary diaphragm are used, which create pressure by displacing the pumped mass. They are simple in design, they do not have valves or spools, which allows them to be quickly disassembled and assembled during sanitary processing, which is necessary when working with food and perishable products. On the rotating shafts of these pumps, at the entrance to the working area, there is an oil seal to prevent possible ingress of lubricating oil into the pumped product.
Self-test questions: What is the machining equipment course based on? What are the objectives of the discipline? How is it common to classify machining equipment? What are overhead tracks? How is it customary to classify overhead tracks? How are overhead tracks divided by purpose? What are rotary pumps used for? What types of rotary pumps are there?
1. Classification of food production equipment and requirements for it
All technological machines and devices can be classified according to the type of processes occurring in raw materials, semi-finished products and finished products during technological processing. In this case, technological machines and devices can be combined into the following groups:
technological machines and apparatus for performing hydromechanical processes (equipment for sedimentation, filtering, fluidization, mixing, washing, cleaning, cutting, wiping);
technological machines and apparatus for performing heat transfer and mass transfer processes (equipment for heat treatment, extraction, drying and baking);
technological machines and devices for performing mechanical processes (equipment for grinding, weighing, dosing, pressing, sifting, calibrating, molding, packaging).
Requirements for devices
An expediently constructed device must satisfy operational, structural, aesthetic, economic and safety requirements.
Operational Requirements
Compliance of the device with its intended purpose. The purpose of the apparatus is to create conditions that are optimal for carrying out the process. These conditions are determined by the type of process, the state of aggregation of the processed masses, their chemical composition and physical properties (viscosity, elasticity, plasticity, etc.). The apparatus must be given a form that would provide the necessary technological conditions for the process (pressure at which the process takes place; speed of movement and degree of turbulization of the flow of processed masses; creation of the necessary phase contact; mechanical, thermal, electrical and magnetic influences). Let's consider an elementary example. It is required to heat and mix a viscous solution containing suspended particles of a thermally unstable substance (for example, a sugar solution containing sugar crystals). Two devices can be used for this purpose. In the apparatus shown in Fig. 1, It is inevitable that solid particles will settle on the bottom and corners. In these places, burning and destruction of the product will occur. Consequently, the shape of this apparatus does not create the conditions necessary for the process to occur. The device shown in Fig. 1 satisfies its intended purpose to a greater extent. 2. The apparatus has a spherical bottom coupled with a cylindrical body and an anchor-type stirrer. All this prevents the formation of sediment and its burning on the walls of the bottom. From the above example it is clear that in order to design an apparatus, it is necessary to know and take into account the properties of the system being processed. Neglect of technological requirements leads to product damage.
High intensity of operation of the device. One of the main characteristics of the apparatus is its productivity - the amount of raw materials processed in the apparatus per unit of time, or the amount of finished product produced by the apparatus per unit of time. When producing piece products, productivity is expressed by the number of pieces of the product per unit of time. When producing mass products, productivity is expressed in mass or volume units per unit of time. The intensity of a device’s operation is its productivity related to any basic unit that characterizes this device. Thus, the intensity of the dryer’s operation is expressed by the amount of water removed from the material in 1 hour per 1 m 3dryer volume; intensity of operation of evaporators - the amount of water evaporated in 1 hour, referred to 1 m 2heating surfaces. It is obvious that in order to achieve high productivity with small overall dimensions of the devices, process intensification is the main production task. The ways in which it is achieved are different for different types of devices. However, it is possible to establish some general methods for increasing the intensity of operation of devices, independent of their design. Intensification can be achieved, for example, by replacing periodic processes with continuous ones: in this case, time spent on auxiliary operations is eliminated, and control automation becomes possible. In some cases, the intensity of operation of the apparatus can be increased by increasing the speed of movement of its working parts. Resistance of the device material against corrosion. The material from which the device is constructed must be stable when exposed to the processed media. In turn, the products of interaction between the environment and the material must not have harmful properties if the product is used for food. Low energy consumption. The energy intensity of the device is characterized by energy consumption per unit of processed raw materials or manufactured products. All other things being equal, the apparatus is considered more perfect, the less energy is spent per unit of raw material or product. Availability for inspection, cleaning and repair. For proper operation of the device, it is subjected to systematic inspection, cleaning and routine repairs. The design of the apparatus must ensure the ability to perform these operations without long stops. Reliability. Reliability of the apparatus and machine is the ability to perform specified functions and maintain its performance within specified limits for the required period of time. The reliability of the device is determined by its reliability, maintainability, and durability. Reliability and durability are indicators that are of great importance and determine the feasibility of the device. Safety requirements. Ergonomics At socialist enterprises, devices are subject to safety requirements and ease of maintenance. The device must be designed and constructed with an adequate safety margin, equipped with protective devices for moving parts, safety valves, circuit breakers and other devices to prevent explosions and accidents. Operations for loading raw materials and unloading finished products should be convenient and safe for working personnel. This is ensured by the appropriate design of hatches and valves. Hermetically sealed continuous devices with a continuous flow of materials are the safest. For ease of maintenance, the device should be controlled from one point where the control panel is installed. This is especially easy to do if remote monitoring and remote control of the device are organized. The highest form is complete automation of monitoring and control. Operating the device should not require significant physical labor. In the conditions of the technical revolution, ergonomics—the science of adapting working conditions to a person—gained great importance. Ergonomics considers practical issues that arise when organizing human work, on the one hand, and the mechanism and elements of the material environment, on the other, In modern conditions, when a person managing a process deals with fast-flowing intensive processes, there is an urgent need to adapt them to the physiological and psychological capabilities of a person in order to provide conditions for the most effective work, which does not pose a threat to human health and is performed by him with less effort. When constructing apparatus, ergonomic requirements are that the operator’s work process be adapted to his physical and mental capabilities. This should ensure maximum work efficiency and eliminate possible health hazards. Another important requirement specific to food production equipment arises from the purpose of the products of food enterprises. In food production facilities, high sanitary and hygienic conditions must be ensured to prevent the possibility of infection of products or contamination by products of the environment and the material from which the apparatus is constructed. This is ensured by the tightness of the devices, design forms that allow for thorough cleaning, automation that makes it possible to carry out the process without the touch of human hands, and the selection of appropriate material for constructing the device. Structural and aesthetic requirements This group includes requirements related to the design, transportation and installation of the device. The main ones are the following: standardization and replaceability of device parts; least labor intensive during assembly; ease of transportation, disassembly and repair; minimum weight of both the entire apparatus and its individual parts. Let's consider the requirements for the mass of the device. Reducing the weight of the device reduces its cost. This can be achieved by eliminating excess safety margins, as well as by changing the shape of the apparatus. Thus, when designing cylindrical devices, if possible, one should choose a height-to-diameter ratio such that the ratio of surface area to volume is minimal. It is known that the surface area of cylindrical vessels with flat lids is minimal at N/A = 2. With this ratio, the mass of metal spent on constructing the cylindrical apparatus is also minimal. Metal consumption can also be reduced by replacing flat covers with convex ones. In many cases, a significant reduction in the weight of the apparatus is caused by the transition from riveted structures to welded ones, the rationalization of the design of individual components, the use of high-strength metals and plastic materials (textolite, vinyl plastic, etc.). When designing devices, it is also necessary to pay attention to the manufacturability of the equipment. Technological (from the point of view of mechanical engineering) is a design that can be manufactured with the least amount of time and labor. The device should have a shape and color that is as pleasing to the eye as possible. Economic requirements The concept of optimization in design. The economic requirements for devices can be divided into two categories: requirements for the design and construction of devices and requirements for the constructed machine that is in operation. From the point of view of these requirements, the cost of designing, constructing and operating the machine should be as low as possible. Devices that satisfy operational and design requirements inevitably also meet economic requirements. With the introduction of new technology and more modern devices, it may happen that the more modern device turns out to be more expensive. However, in this case, as a rule, the cost of operating the devices decreases, and the quality of the product improves, and, thus, the introduction of a new device becomes expedient. Economic requirements are discussed in more detail in courses on production organization and industrial economics. When designing a device, it is necessary to strive to ensure that the process occurring in it is carried out in an optimal way. The optimization problem is to choose an option in which the value characterizing the operation of the apparatus (optimality criterion) has the optimal value. Product cost is most often chosen as an optimality criterion. In this case, the designer is faced with the task of designing a device with such data that will ensure the minimum cost of production. The most important stage of optimization is the selection of optimization criteria and the preparation of a mathematical model of the apparatus. Using this model, with the help of electronic computers they find the optimal solution. polishing grinding food grade 2. Mechanical processes
Grinding Grinding and polishing is used in the processing of millet, oats and corn (grinding), rice, peas, barley and wheat (grinding and polishing). When grinding, the fruit and seed shells, partly the aleurone layer and the embryo are removed from the surface of the hulled grain. Sanding improves the appearance, shelf life and cooking properties of the crepe. However, grinding reduces the biological value of the cereal, since a significant portion of the vitamins, complete proteins, and minerals found in the germ, aleurone layer and outer parts of the mealy kernel are removed with fiber and pentosans. Rolling deck machine SVU-2(fig.) is intended for peeling buckwheat and millet. Has one deck. The grain flakes between the abrasive drum and the stationary abrasive or rubber deck. Rolling deck machine SVU-2 From the receiving hopper 7, through the feed roller 2 and the hinged valve 3, the grain, distributed along the length of the rotating drum 4 and deck 5, enters the working area 6. The base of the drum is a cylinder made of sheet steel with angles 7 located along the generatrices. To regulate the size and shape of the working area, a mechanism is used, consisting of a deco holder 8 and a movable part 9 of the support, which can be moved along the support 12 by means of a nut 10 and a screw 77. By turning the screw using the steering wheel 14, you can change the size and shape of the working area of the machine. This is necessary, for example, for shelling buckwheat, when it is necessary to give the working area a crescent shape. In the lower part of the decoder holder there are pins 18 installed on both sides, connected to a screw rod 19. By turning the flywheel 20, you can change the position of the deck and give the working area a wedge-shaped shape - optimal for peeling millet. Peeling products are removed from the machine through pipe 17. The machine is driven by an electric motor 15 through a V-belt drive 16. In order to remove the deck, the support 12 together with the deck is rotated to the appropriate angle around the axis 13. Sufficiently high technological performance is achieved by using buckwheat for peeling sandstone drum and deck, and for millet peeling - an abrasive drum and elastic deck made of special rubber-fabric plates of the RTD brand. To peel buckwheat, after 24...36 hours it is necessary to cut the sandstone drum and deck with grooves 1.0...1.2 mm deep with an inclination of 4...5° to the generatrix. The number of grooves is 4...6 per 1 cm of drum circumference, depending on the size of the processed grains. When peeling millet, you need to restore the rough surface of the abrasive drum every 3-4 days and grind the rubberized deck onto the roller. The working surface of the drum when processing: buckwheat - sandstone, millet - abrasive. The working surface of the deck when processing: buckwheat - sandstone, millet - rubber. The shape of the working area of the machine during peeling: buckwheat - sickle-shaped, millet - wedge-shaped. Peeling and grinding machine A1-ZSHN-Z(Fig. 4) is intended for peeling rye and wheat during wallpaper grinding and rye varietal grinding at flour mills, grinding and polishing barley during the production of pearl barley, and peeling barley at feed mills. The sieve cylinder 4 of the machine is installed in the housing 5 of the working chamber, the shaft 3 with abrasive wheels 6 rotates in two bearing supports 8 and 12. In the upper part it is hollow and has six rows of holes, eight holes in each row. Peeling and grinding machine Al-ZSHN-Z The machine is equipped with inlet 7 and outlet 1 pipes. The latter is equipped with a device for regulating the duration of product processing. The outlet pipeline is attached to the flange of the pipe installed in the area of the annular channel (for the flour outlet) of housing 2. The machine is driven by an electric motor 9 through a V-belt drive 11. Housing 5 of the working chamber is attached to housing 2, which in turn is installed on frame 10. The grain to be processed enters the space between the rotating abrasive wheels and the stationary perforated cylinder through the receiving pipe. Here, due to intense friction as the grain moves to the outlet pipe, the shells are separated, the bulk of which is removed from the machine through the holes of the perforated cylinder and then through the annular chamber. With the help of a valve device located in the outlet pipe, not only the amount of product released from the machine is regulated, but also its processing time, the productivity of the machine and the technological efficiency of the peeling, grinding and polishing process. Air is sucked in through the hollow shaft and the holes in it and passes through the layer of the product being processed. Together with shells and light impurities, it enters the annular chamber through a sieve cylinder and then into the aspiration system. One of the most common malfunctions is increased vibration of the machine, which occurs due to wear of the abrasive wheels. Greater wheel wear also leads to a decrease in processing intensity. Therefore, the condition of the circles must be carefully monitored and replaced in a timely manner. When replacing a perforated cylinder, it is necessary to release only one cover from its fastening, remove it, and then remove the cylinder through the resulting annular slot. Al-ZShN-Z peeling and grinding machines are produced in four versions with abrasive wheels for different grain sizes (from 80 to 120). (Fig. 5) is intended for grinding rice cereals. Grinding machine A1-BSHM - 2.5 Hulled rice with a content of unhulled grains of no more than 2% is subjected to grinding. The grinding machine consists of two grinding sections 15 and 19, mounted in a housing, and a frame 4. Each grinding section has a feeder 18, a receiving pipe 12, a hinged cover 16, a sieve drum 9, a grinding drum 8, an unloader and an electric motor 20. The machine is closed from the outside by walls 7 and 7. A hopper 2 is installed under the grinding sections 15 and 19 to collect and remove flour from the machine. The drive has a protective guard 13 and a door 14 for maintenance. Grinding drum 8 is made of abrasive wheels. On the product inlet side, it has a screw feeder 10, and on the outlet side, an impeller 5. The unloader 6 is a cast cup with a hole that is closed by a load valve. A weight moves along the threads on the valve lever. Rice grains enter the grinding section through a feeder and are fed by a screw into the working area, where, passing between the rotating grinding and sieve drums with races, they are subjected to grinding. At the same time, the flour spills through a sieve into hopper 2 and is removed by gravity from the machine. The ground grain, overcoming the force of the load valve, enters pipe 3 and is also removed from the machine. Setting up a grinding machine involves choosing the optimal duration for processing rice grains. For this purpose, as indicated above, the unloaders are equipped with load valves, which make it possible to regulate the support force in the working area by changing the position of the weights on the levers. By visually observing the outgoing product through the hatch of the unloading pipe, as well as the load of the electric motor according to the ammeter reading, the required reinforcement of the cargo valve and the position of the lower damper of the feeder are selected. 3. Hydromechanical processes
Basic principles of filtering Due to the small size of the holes in the sediment layer and the filter partition, as well as the low speed of movement of the liquid phase in them, it can be considered that filtration occurs in the laminar region. Under this condition, the filtration rate at any given moment is directly proportional to the pressure difference and inversely proportional to the viscosity of the liquid phase and the total hydraulic resistance of the sediment layer and the filter wall. Due to the fact that in the general case, during the filtration process, the values of the pressure difference and hydraulic resistance of the sediment layer change over time, the filtration speed is variable w(m/sec) are expressed in differential form, and the basic filtration equation has the form: where V is the volume of filtrate, m3; S- filtration surface, m2; t -
filtering duration, sec; D.R. -
pressure difference, N/m2; m -
viscosity of the liquid phase of the suspension, N×sec/m2; Roc - sediment layer resistance, m-1; Rf.p. -
resistance of the filter partition (it can be considered approximately constant). As the thickness of the sediment layer increases, the value of Roc changes from zero at the beginning of filtration to the maximum value at the end of the process. To integrate equation (1), it is necessary to establish the relationship between Roс
and the volume of the resulting filtrate. Taking into account the proportionality of the volumes of sediment and filtrate, we denote the ratio of the volume of sediment Voc to the volume of filtrate V by x0. Then the volume of sediment Voс = x0×v. At the same time, the sediment volume can be expressed as Voс = hoc×S, where hoc is the height of the sediment layer. Hence: V×xo=hoc×S. Hence, the thickness of a uniform layer of sediment on the filter partition will be: and his resistance where ro is the resistivity of the sediment layer, m-2. Substituting the Roc value from expression (3) into equation (1) we obtain: . (4) .
Literature
1. Dragilev A.I., Drozdov V.S. Technological machines and devices for food production. - M.: Kolos, 1999, - 376 p. Stabnikov V.N., Lysinsky V.M., Popov V.D. Processes and apparatus of food production. - M.: Agropromizdat, 1985. - 503 p. Machines for peeling and grinding grain crops. #"justify">. Processes and apparatus of food production: lecture notes for the PAPP course Part 1. Ivanets V.N., Krokhalev A.A., Bakin I.A., Potapov A.N. Kemerovo Technological Institute of Food Industry. - Kemerovo, 2002. - 128 p.
MINISTRY OF EDUCATION OF THE RF
YAROSLAVSK STATE TECHNICAL UNIVERSITY
Department of Processes and Apparatuses of Chemical Technology
UDC 66.011; 663; 664
B.C. SALNIKOV
PROCESSES AND APPARATUS
FOOD PRODUCTION
Course of lectures for 3rd year students /6th semester/
Specialties 170600 "Machines and apparatus for food
Production", direction 551800 "Technological
Cars and equipment".
PAKHT. 46. 170600. 551800. KL
Yaroslavl - 2002.
attendance and performance for the 6th semester
Attendance: 38 + 12 + 20 = 70
Lab reports: 5 x 20 = 100
Abstract /at the request of the student/: 50 /printed 60/
Total: 70 + 100 + 50 = 220
Automatic departmental examination, interview and release
from the exam with the score:
220-210 – excellent, 200-190 – good.
Cathedral credit – 140-150.
^ TOPICS OF LECTURES– 38 hours
Introductory – 4 hours.
Hydromechanical processes – 8 hours.
Thermal processes – 10 hours.
Mass transfer processes – 16 hours.
HYDROMECHANICAL PROCESSES – 8 hours.
Classification, general theory – 2 hours.
Filtration – 2 hours.
Fluidization – 2 hours.
Stirring – 2 hours.
THERMAL PROCESSES – 10 hours.
Basics of heat exchanger calculation – 4 hours.
Evaporation – 6 hours.
MASS TRANSFER PROCESSES – 16 hours.
Fundamentals of mass transfer – 4 hours.
Distillation – 2 hours.
Rectification – 4 hours.
Drying – 6 hours.
PRACTICAL LESSONS – 12 hours.
Calculation of a 3-body direct-flow evaporation plant – 4 hours.
Calculation of a continuous distillation unit for
separation of a binary mixture – 4 hours.
Calculation of convective dryers: fluidized bed and drum using flue gases as an agent – 4 hours.
TOPIC
LABORATORY LESSONS – 20 hours.
No. 28 – Filtration – 4 hours.
No. 27 – Fluidization – 4 hours.
No. 21 – Mechanical stirring – 4 hours.
No. 23 – Heat exchanger test – 4 hours.
No. 24 – Kinetics of convective drying – 4 hours.
The purpose of the design is the final test of students’ mastery of the course, carried out in the process of their independent engineering work.
The course project includes the calculation of a typical installation (evaporation, drying, rectification) and its graphic design. The calculation and explanatory note contains a description of the installation diagram, apparatus design, material, thermal, structural and mechanical calculations, safety measures, and a list of references. The volume of the note is 20-40 typewritten pages. Carrying out calculations involves the use of computer technology.
The graphic part of the course project consists of a drawing of a general view of the installation in 2-3 projections and a drawing of the main apparatus with sections and components made on sheets of A1 format.
During the work period, students become familiar with current GOSTs, use reference literature, and acquire skills in selecting equipment.
^ 2.6. Contents of student’s independent work
Independent work consists of systematic study of the lecture course, independent study of individual sections and topics of the course, mastering questions submitted for independent study and designing laboratory work, completing and designing course projects, preparing for tests and exams.
Main:
Planovsky A.N., Nikolaev P.I. Processes and devices of chemical and petrochemical technology. M., Chemistry, 1987.
Kasatkin A.G. Basic processes and apparatuses of chemical technology. M., Chemistry, 1973.
Stabnikov V.N., Lysyansky V.M., Popov V.D. Processes and apparatus of food production. M., Agropromizdat, 1985.
Gelperin N.I. Basic processes and apparatuses of chemical technology. M., Khi-miya, 1981.
Pavlov K.F., Romankov P.G., Noskov A.A. Examples and tasks for the course on processes and apparatus of chemical technology. L., Chemistry, 1987.
Dytnersky Yu.I. Basic processes and apparatuses of chemical technology. Design manual. M., Chemistry, 1983.
Certain technological processes: filtering, evaporation, drying, etc. were known to mankind in ancient times and were used exclusively for food purposes. Very primitive equipment was used. But PAPP are the ancestor and historically developed earlier than PACT.
The concept of "deep antiquity" is largely relative. Archaeologists do not yet have a coherent system of human origins. It is known that the skeleton of the most ancient man was found in Africa. The age of the skeleton is 5 million years. However, the emergence of a culture of agriculture and cattle breeding, associated with various tools and household items, is usually attributed to the end of the Ice Age, i.e. 75-100 thousand years ago. We will call this time “deep antiquity.”
The sugar and distillery industries had a significant influence on the development of PAPP. Initially, the raw material for sugar production was sugar cane (homeland - India, China, Oceania). Even in ancient times, sweet syrup was obtained in India by evaporation. Hard sugar (crystallization) was apparently learned by the Arabs 800 years ago. Columbus brought cuttings of sugar cane to the Antilles. After this, Cuba and Puerto Rico became the main centers of sugar production in the world.
At the end of the 18th century, the search for sugar cane substitutes began in Russia, which culminated in the discovery of sugar beets. The first beet sugar factory was built in Russia in 1802. Around the same time, the first plant appeared in Germany, and a few years later - in France. In 1812, an industrial vacuum evaporator was created, and in 1820, a filter press.
At the end of the Ice Age, people began to live in camps /wooden and stone settlements/. When men hunted, women and children collected edible berries, fruits, roots and herbs from the surrounding area. Excess fruits and berries were placed in clay pits calcined by fire. After a month of storage at a temperature of 25-30 ° C, due to natural fermentation, dry wine was obtained from fruits and berries. This drink saved people from many intestinal diseases and helped to prolong life (on average it was 30-35 years). The discovery of alcohol led to the creation of a special human culture - winemaking. 7 thousand years ago in ancient Egypt, the production of wine from grapes was already put on stream, in China - 5 thousand years ago. Ceramic and wooden vessels were used.
The first attempts to distill dry wine were made in ancient Egypt /Alexandria/ by a monk named Zosima de Panopolis. In 1334, an alchemist from Provence (France) Arnaud de Villeneuve obtained wine alcohol by distillation.
From time immemorial, honey beer and mash have been prepared in Rus'. The production of this “mead” is still preserved in Suzdal. In the 14th century, the monk Isidore “spied” the construction of a moonshine still abroad and built the same one in a monastery near Moscow. To prepare mash, they began to use grain (wheat, rye, barley, oats) and yeast (potatoes in Germany, cellulose in Sweden). In 1813, an industrial distillation column was created.
Oil and flammable gases were known to people since ancient times. Oil was used to fill lamps and incendiary bombs, and in ancient Egypt they embalmed the dead. Distillation, adopted from the distilling industry, had a significant impact on oil refining. Industrial oil refining appeared in the 18th century. Thus, in 1745, in the Pechora region on the Ukhta River, Fedor Pryadunov at the merchant Nabatov’s factory annually produced 20 thousand liters of purified kerosene. In Germany, kerosene was obtained from oil in 1830 /Reichenbach/, in the USA - 1858 /Colonel Dreck/.
Petroleum refining essentially shaped chemical technology. Attracting significant material resources and scientific personnel, HT became dominant in the 20th century. CT itself, in turn, began to be subdivided into separate areas and industries: basic organic synthesis (OOS), synthetic rubber technology (SC), paint and varnish, etc. The food and chemical-pharmaceutical industries became an integral part of CT. For example, drum dryers developed by HT can be used for drying both quartz and granulated sugar.
The Ice Age, the remnants of which are still observed today, being essentially a natural refrigerator, contributed to the preservation of perishable foods: meat, poultry, fish, etc. - and, oddly enough, to the survival of humanity. A mammoth carcass caught in the summer could feed people for a maximum of a week, after which the meat spoiled. In winter, the same carcass could feed people for several months. Until now, some farms prepare ice in the winter and keep it underground in the summer to preserve food. In the permafrost layer (tundra), special storage facilities have been created in which the state stores strategic reserves of meat throughout the year.
According to the domestic astronomer prof. I.S. Shklovsky /Stars: their birth, life and death. – 1984, p.146/ Earth is experiencing an ice age that has lasted for 2 million years, and the usual duration of ice ages / they occur every 200-300 million. years/ is 10 million years. Now we have a short respite /15 thousand years/, but already in this century astronomers expect a sharp cooling of the Earth’s climate. The greenhouse effect, perhaps invented for edification, is not confirmed by calculations.
For oil refining, the natural refrigerator turned out to be completely insufficient. It was necessary to condense vapors of highly volatile hydrocarbons and liquefy the gases. Artificial cooling was required. In 1845 an air refrigeration machine was created, in 1874 a vapor compression machine was created, and in 1895 deep cooling appeared. / liquid nitrogen/. The food industry did not go unnoticed by HT: now it is difficult to find a food or commercial enterprise that does not have a vapor compression refrigeration machine (deep cooling is also used for quick freezing of food products).
Chemical technology largely works for the food industry, for example, it supplies agriculture with: fuels and lubricants, mineral fertilizers / unfortunately, in Russia currently 85% fertilizers are exported/, herbicides / against weeds/, insecticides / against harmful insects, surprisingly, people completely forgot about locusts, and they suddenly appeared in the summer of 2001, first in Kazakhstan, then spread to Dagestan and the Stavropol Territory/, microelements for plant growth and etc.
If Tsarist Russia was mainly an agricultural country and exported grain /the British still prefer black bread baked from Russian rye/, as well as other products, then currently Russia imports /imports/: meat 34%, milk and dairy products products 20%, sugar 70%, vegetable oil 41%.
The insufficiency of agriculture in providing food has given rise to the desire to create artificial food. The beginning was made by chemical technology in the 19th century.
In 1854, Berthelot synthesized fats (glycerol + fatty acids). During the Second World War, a plant was built in Germany to produce tens of thousands of tons of butter substitute /margarine/. Currently, margarine is also produced from vegetable oil. Natural butter is several times more expensive than margarine. The paradox is that, as an audit published in the media showed, there are now only two types of Vologda natural butter left in Russia. All other butter is margarine, but is sold at the price of natural butter.
The first synthesis of sugar was carried out by the domestic scientist A.M. Butler in 1861 /paraformaldehyde + alkali = sugar close to glucose/. The synthesis of grape sugar, which occurs in nature /α - glucose/, was carried out in 1890 by Emil Fischer /from glycerol/. Glycerin is also used as a cosmetic and food additive.
With the synthesis of proteins, the matter turned out to be much more complicated and the problem is still far from being solved. Chemical scientists have followed the path of splitting natural proteins into amino acids, studying the structure and synthesis of the latter, and then combining them into protein molecules. The first amino acid, glycine, was obtained by Braconneau in 1820 /L. and M. Fizer. Organic chemistry. – 1949, p. 359/. Since then, several dozen amino acids have been studied, some of them synthesized. Protein-like substances (plasteins) with a molecular weight of 100 thousand or more were obtained. Natural proteins have a mol. mass of several million /proteins/. The work received a chemical-pharmaceutical and medical direction. As a result, the following were developed: ultracentrifugation, X-ray diffraction analysis, extraction (the latter is included in the discipline of PAPP). Canadian scientists Banting and McLeod were awarded the Nobel Prize for the discovery of insulin /1921/. However, hormonal proteins (for example, insulin, thyroxine, adrenaline) obtained synthetically are still in many ways inferior to natural proteins obtained by extraction from a bull carcass (pancreas and thyroid glands, adrenal cortex). Therefore, in the future it is advisable for the meat processing plant to have an additional workshop in the form of a pharmaceutical factory, because Medicines obtained from the carcass of a bull are much more expensive than the cost of the bull itself.
For mass production after the Second World War, feed protein was created from oil and wood. Recently, soybeans have been attracting more and more attention from food scientists. Soybean grain contains: 24-45% protein, 13-27% fat, 20-32% starch. The preparation of milk and cheese from soybeans (hard to distinguish from cow's milk) was known to the Chinese in ancient times. Here's the thing again: soy protein, processed and formed into fibers that combine to form pieces of "meat," is now sold in cans labeled "beef" and priced like beef.
Ethyl alcohol /ethanol/ is an important raw material in the production of environmental protection and safety equipment. In the 19th century, ethanol was produced by alcoholic fermentation, which has already been discussed. In 1855, Berthelot obtained ethanol under laboratory conditions using the sulfuric acid method of ethylene hydration. In industry, the method was implemented in 1919 /USSR - 1933/. In 1948, in the USA and USSR, the industrial synthesis of ethanol was carried out by direct hydration of ethylene / temperature 290-300 ° C, pressure 7-8 MPa, catalyst - phosphoric acid. Technical ethanol obtained by this method contains up to 2% diethyl ether / boiling point 34.5 ° C, and has a pleasant odor. The latter is very toxic: it causes loss of consciousness and can lead to sudden cardiac arrest. Recently, industrial alcohol has poured into the food industry like a river (it was even discovered at the Yaroslavl Distillery Plant). As a result, several tens of thousands of people die every year in Russia from drinks containing industrial alcohol.
Thus, the chemical industry, which has mainly large-scale production, is currently, and even more so in the future, able to provide the food industry with millions and millions of tons annually of synthetic food raw materials: fats, carbohydrates, proteins. According to doctors, artificial food cannot completely replace food from natural products, because Millions of years of evolution have best adapted the human body to the latter food. It has been proven that the absence of natural proteins in food (meat, poultry, fish, dairy products, etc.) leads to depletion of the human body and even death. Therefore, doctors oppose vegetarianism and all kinds of “fasts”. Adulteration of natural food products, which has been observed recently, must be prosecuted by law.
Generalization of production experience in chemical and related technologies dates back to the beginning of the 19th century. In Russia in 1828, prof. F. Denisov published a work entitled “A lengthy guide to general technology...”, in which he expressed the idea of the commonality of a number of basic processes and apparatuses. At the end of the 90s of the 19th century, prof. Alexander Kirillovich Krupsky introduced an academic discipline in the calculation and design of basic processes and apparatus at the St. Petersburg Institute of Technology. In 1909 A.K. Krupsky published a book entitled “Initial Chapters of the Study of Design in Chemical Technology,” which is essentially the first textbook on the discipline of chemical engineering. In 1912 prof. Ivan Aleksandrovich Tishchenko introduced the PACT course as an independent discipline at the Faculty of Chemistry of the Moscow Higher Technical University.
In the USA, it was only in 1923 that the work of Walker, Lewis and McAdams, entitled “Principles of the Science of Processes and Apparatus,” was published. The book “Basic Processes and Apparatus of Chemical Production” by V. Badger and V. McCab was published in the USA in 1931 as a textbook.
Great contribution to the development of certain branches of process science
and devices were contributed by domestic scientists I.A. Tishchenko /calculation theory
evaporators/, D.P. Konovalov /basics of the theory of liquid distillation
mixtures/, L.F. Fokin and K.F. Pavlov /original and deep in content monographs/. Further, the ideas of the course were developed by domestic scientists: A.M. Tregubov, S.N. Obryadchikov, A.G. Kasatkin, N.M. Zhavoronkov, A.V. Lykov / Yaroslavl, graduated from Yaroslavl State Pedagogical Institute named after. Ushisky/, P.G. Romankov, A.N. Dlanovsky, N.I. Gelperin, V.N. Stabnikov, V.V. Kafarov and others.
It should be noted the works of Prof. V.N. Stabnikova /Kiev Food Institute/, author of a textbook on the discipline of PAPP.
Stabnikov V.N., Kharin S.E. Theoretical foundations of distillation and rectification of alcohol. – Pishchepromizdat, M., 1951.
Stabnikov V.N. Rectifying devices. – M.: Mashgiz, 1965.
Stabnikov V.N., Popov V.D., Redko F.A., Lysyansky V.M. Processes
and food production equipment. – M.: Pishchepromgiz, 1966.
Stabnikov V.N. Calculation and design of contact devices
rectification and absorption apparatuses. – Kyiv, Technika, 1970.
Stabnikov V.N., Lysyansky V.M., Popov V.D. Processes and apparatus
food production – M.: Agropromizdat, 1985.
Processes and devices common to the food, chemical, chemical-pharmaceutical and other related industries are called main processes and devices.
The study of the theory of basic processes, design principles and methods of calculating devices and machines is item And task course.
One of the objectives of the course is to identify general patterns the occurrence of various processes, for example, for the transfer of matter and heat.
The course examines the patterns of transition from laboratory processes and apparatus to industrial ones, i.e. Problems modeling.
The course studies the so-called macrokinetics, associated with the visible, mass movement of matter: streams, drops, bubbles, solid particles, etc. At the same time, it is used only to explain some phenomena microkinetics, i.e. movement of matter at the molecular level.
^ CLASSIFICATION OF PROCESSES
Depending on the patterns characterizing the flow of processes, the latter are classified:
HYDROMECHANICAL – mixing and separation of heterogeneous gas and liquid systems.
THERMAL - transfer of heat from one coolant to another.
MASS TRANSFER – transferred /predominant/ substances from one phase to another to achieve equilibrium.
The course also includes refrigeration, mechanical and chemical processes. But for this specialty they are considered in other disciplines.
According to the organizational and technical structure, processes can be divided into periodic/non-stationary/ and continuous/stationary/.
IN periodic In the process, its individual stages (for example, heating - boiling - cooling) are carried out in one apparatus, but at different times. Economically, these processes are feasible in small-scale production with a diverse range of products, which is typical for the food industry.
IN continuous of the process, its individual stages are carried out simultaneously, but in different apparatuses /heater - boiler - refrigerator/. They are economically beneficial in medium- and large-scale production (evaporation), allowing for mechanization and automation, as well as the use of standard equipment.
^ GENERAL SCHEME
RESEARCH, DEVELOPMENT AND CALCULATION OF EQUIPMENT
Based laws of statics set the initial and final values of the process parameters and the direction of its flow.
Based law of conservation of matter make up a material balance.
Based law of conservation of energy constitute the energy/heat/ balance.
Based laws of kinetics establish the driving force and speed coefficient of the process.
Based on the data obtained, the main size of the apparatus is determined.
Several equipment options are calculated and, based on a technical and economic analysis, the optimal option is determined.
The laws of statics and kinetics, conservation of matter and energy, being fundamental laws of nature, essentially formed the discipline of PAPP as a science. Science differs from other “teachings” in that the response to a violation of the law in any production follows immediately: accident, fire, explosion, catastrophe, etc. To avoid this, safety precautions /TB/ are passed through the entire course of PAPP. Let us consider the above points of the scheme in a little more detail.
^ PROCESS STATICS
Any process continues until the system reaches a state of equilibrium. Statics considers the process in a state of equilibrium.
There are hydrostatics /the study of the equilibrium of liquids/, as well as thermal, phase and chemical equilibrium.
For example, phase or diffusion equilibrium for saturated solutions in water at 100 °C /solubility/:
Table salt /sodium chloride/ – 39.8 g/100 g of water; 28.5% wt.
Sugar – 487 g/100 g of water; 83% wt.
^ 2. MATERIAL BALANCE
In general, it can be written as follows:
Where 
– the amount of substances received for processing;
– amount of substances obtained as a result of processing
Modern technologies must provide that there should be no losses and waste /waste-free technologies/. But for now they are there.
Waste in the food industry is usually used for fattening animals /additional workshop/.
Losses from the chemical industry quite often poison the environment, including the population. For example, the Yaroslavl Oil Refinery /Slavneft/ annually “loses” 100 thousand tons of hydrocarbons into the atmosphere. In 1999, emissions of pollutants (not only from the chemical industry) into the atmosphere of the city of Yaroslavl amounted to 270 thousand tons.
From Western Europe, with a tailwind, 2 million tons of sulfur dioxide and 10 million tons of sulfates enter Russia annually.
^ 3. ENERGY / HEAT / BALANCE
In general it is written like this:
Where 
– heat supplied with the starting substances,
– thermal effect of the process,
– heat leaving with the final products,
– heat loss to the environment.
Heat loss is inevitable; but they must be minimized /selection of thermal insulation/ or recycled /heat losses of devices are taken into account in the workshop heating system/. One of the best heat insulators is considered to be fiberglass /mats/, density 120-200 kg/m 3, thermal conductivity coefficient 0.04 W/m.°C, which is also reliable protection against rodents.
Heat losses in the form of a “smoke screen” from furnaces, boiler houses and thermal power plants (TPPs) are associated with environmental pollution. Thus, thermal power plants operating on hard coal emit 15 tons of sulfur dioxide, 10 tons of ash and 3 tons of nitrogen oxides per 1 million kWh of electricity generated.
The discipline of PAPP has an extensive arsenal of equipment for purification (up to the maximum permissible concentration) of flue gases from dust and harmful gas components, as well as for the recovery of heat from them: dust and gas purification devices, contact heat exchangers, absorbers, adsorbers, etc.
^ 4. KINETICS OF PROCESSES
Kinetics examines processes in their development, in their desire to reach a state of equilibrium.
– The degree of deviation of the system from the equilibrium state expresses the driving force of the process.
For discipline processes, PAPP is applicable basic kinetic law:
– The speed of the process is directly proportional to the driving force and inversely proportional to the resistance.
This pattern does not apply to mechanical and chemical processes. But these processes are sometimes located on the same production line with the main processes, for example, sugar beets are crushed or chopped before leaching. Therefore, in some universities, these processes are introduced into the PAPP discipline.
For hydromechanical processes, the main kinetic law takes the form:
/3/
where V is the volume of flowing liquid, m3,
S – apparatus cross-section, m2,
τ – time, s,
ρ – liquid density, kg/m3,
G = 9.81 m/s 2,
R Г – hydraulic resistance, kg/m2.s,
K Г – speed coefficient, m 2 .s/kg,
ΔH d – difference in total hydrodynamic heads, m.
The last value is determined by the Bernoulli equation:
In educational and technical literature, pressure loss in the apparatus /Δp n or h n / is often mistakenly taken for hydraulic resistance.
For thermal processes, the kinetic equation is written:
/5/
Where Q is the amount of heat transferred, J,
F – heat transfer surface, m2,
Δt – temperature difference between coolants, K or °C,
R – thermal resistance, m 2 .K/W,
K – heat transfer coefficient, W/m2.K.
For mass transfer processes:
/6/
Where M is the amount of substance transferred from one phase to another, kg or kmol,
F – phase contact surface /mass transfer/, m2,
K Y – mass transfer coefficient, kg/m 2 .c. 
,
R Y – diffusion resistance, m 2 .s. /kg,
ΔY – the difference between the equilibrium and working (or vice versa) concentrations for one of the phases, kg A/kg B – relative mass fractions, or kmol A/kmol B – relative mole fractions.
For example, if pure water /Y=0/ is used to dissolve sugar at 100 °C, then at the initial moment of time the driving force of the dissolution process will be:
ΔY = Y us. – Y = 487/100 – 0 = 4.87 rel. wt. shares
^ 5. MAIN SIZE OF THE UNIT
Determined from the integral form of equations /3, 5, 6/, for example, from equation /5/, i.e. from the basic heat transfer equation:
/7/
Δt av – average temperature difference between coolants, K or °C.
Based on the main size, the device is accepted according to the catalog /standard/ or is developed structurally /non-standard/.
^ 6. TECHNICAL AND ECONOMIC ANALYSIS
Calculations on this topic are usually very cumbersome, so they are carried out using a computer. Thus, 264 options are possible for calculating the heat exchanger.
First of all, the optimality criterion is adopted. There can be several such criteria: economic /unit cost of production, production profit, etc./, production /productivity, product quality, etc./, etc. The optimal option is accepted according to the maximum or minimum of the optimality criterion. When choosing options, among other things (for example, the type of coolant, its initial temperature, etc.), the following are taken into account:
A/ the material of the device must comply with safety requirements - durability, anti-corrosion, harmlessness;
B/ human adaptation /ergonomics/;
B/ aesthetic requirements;
G/ environmental requirements.
MATERIALS
A. Metals
Contact with food products of metals such as Fe, Al, Cu, Zn, Cd, Ni, Ti, which are still used alone or in the form of coatings, should be avoided.
Toxicity of the above metals.
/Grushko Ya.M., Harmful inorganic compounds in industrial emissions into the atmosphere. Ref. ed. – L.: Chemistry, 1987. – 192 p./
Al – aluminum /melting point 660.4 °C, density 2699 kg/m 3 /.
Faced with such a “prospect,” a desire arises to collect all the household aluminum utensils and sell them for scrap.
Fe – iron /1539 °C, 7870 kg/m 3 /.
Сd – cadmium / 321.1 °С, 8650 kg/m 3 /.
Сu – copper /1084.5 °С, 8960 kg/m 3 /.
Ag – silver /261.9 °C, 10500 kg/m 3 /.
Zn – zinc /419.5 °C, 7130 kg/m 3 /.
Ni – nickel /1455 °C, 8900 kg/m 3 /.
Ti – titanium /1665 °C, 4320 kg/m 3 /.
/Malakhov A.I., Andreev N.Kh. Structural materials of chemical equipment. – M.: Chemistry, 1978. – 224 p./
A/ Corrosion-resistant / stainless / structural steels.
For example, steel 2Х13 /0.2% carbon, 13% chromium/, heat resistance up to 600 °C, tensile strength 850 MPa.
B/ Ordinary carbon steels st.2 and st.Z with coating:
– tin, Sn, /231.9 °C, 5850 kg/m 3 /, tin, tin cans.
– enamels based on organosilicon compounds / enamels density 2100-2500 kg/m 3, heat resistance up to 300 °C, compressive strength 600 MPa.
– Teflon /polymer CF 2 =CFCl or fluoroplastic 3/, density 2100-2160 kg/m 3, heat resistance up to 210 °C, tensile strength 35-40 MPa.
B. ^ Silicate materials
The data is summarized in table 1.
Table 1.
Particular attention should be paid to glass ceramics – the materials of the future. Sitall is a transparent, corrosion-resistant material, superior in strength to ordinary carbon steel, and much lighter in density (at the level of aluminum). Recently, equipment (including pipelines) for milk processing workshops, distillation columns (still of small capacity), etc. have been made from glass ceramics.
IN. ^ Polymer materials
Fluoroplast 4 – tetrafluoroethylene polymer, density 2160-2260 kg/m 3, tensile strength 14-25 MPa, maximum temperature 327 °C /pipes, fittings, gaskets, etc./.
Fluorine rubber / conventional name for rubber containing fluorine rubber and up to 30% wt. filler - silicic acid, vulcanization is carried out using diamines / - density 1800-1900 kg/m 3, tensile strength 20-25 MPa, maximum temperature 200-250 ° C / hoses, tapes, gaskets, etc./.
G. ^ Other materials
In this section, we should note materials that are not structural for industry, but are very widely used in artisanal production (winemaking, fermentation, etc.), as well as for the manufacture of household utensils.
Wood - density of raw wood 300-900 kg/m 3, compressive strength: fir - 47, oak - 65 MPa; heat resistance up to 150 °C, flash point /when adding fire/ 230-260 °C, auto-ignition temperature: /heating without fire/ about 400 °C.
Ceramics /faience/ – a fired mixture of pottery clay, quartz sand, feldspar, etc., covered with glaze. Firing temperature 1250-1300 °C, density 1800-1900 kg/m 3, compressive strength 100-130 MPa.
^ STRENGTH CALCULATION
For devices operating under internal excess pressure, a strength calculation must be submitted according to the Gosgortekhnadzor formula. Apparatus wall thickness:
mm /8/
Where D in is the internal diameter of the device, mm,
P – design pressure, MPa /1.03-1.1 from nominal/,
φ – correction factor for weld strength /1.0-0.8/,
C – corrosion allowance, mm,
σ add – permissible stress, MPa.
For devices located outdoors, wind load calculations are carried out. The wind speed is assumed to be 45 m/s / hurricane speed is 33 m/s/. For rotating drums with two supports, bending calculations are carried out. For gratings operating under load, shear calculations are provided.
^ ERGONOMICS, AESTHETIC REQUIREMENTS
Ergonomics is a science that studies the mutual adaptation of man and machine. Ergonomic indicators reflect the interaction of a person with technology in the complex of hygienic, anthropometric, physiological and psychological properties of a person.
Ergonomics is directly related to safety precautions, in fact, it came out of it. When choosing equipment options, for example, it is necessary to provide for guards for rotating parts, convenient shape and location of control handles, and low effort to activate them. There must be sufficient passages between devices for ease of maintenance and repair. If the devices are located in the open air (evaporation, rectification), then the operator’s workplace should be organized nearby in the room. Illumination, temperature and humidity in the workplace must comply with the /air conditioning/ standard. The workplace must be protected from dust, noise, vibration, radiation, harmful substances, and have an emergency exit for urgent evacuation. The staff is provided with special clothing (helmet, jacket, trousers, boots, mittens, goggles, etc.), drinking water (tea and coffee allowed), hot shower, etc.
Aesthetic indicators characterize information expressiveness, rationality of form, integrity of composition, perfect execution of devices and machines. The color design of the devices and workplace is of no small importance.
For safety reasons, the following coloring of pipelines is accepted:
Water vapor is red,
Purified water – green,
Fire pipeline - orange,
Process water – black.
^ ENVIRONMENTAL REQUIREMENTS
Ecology is the relationship of organisms with each other and with the environment.
Environmental indicators are the level of harmful effects on the environment that arise during the operation of equipment, for example, the content of harmful impurities, the likelihood of emissions of harmful particles, gases, radiation, etc.
In conditions of payment for natural resources, payment for environmental pollution also arises. Depending on the amount of pollution, payments are made for discharges of pollutants. The amount of payments is established on the basis of the draft standards for maximum permissible discharges /MPD/ and emissions /MPE/.
Integrated emissions indicator
/9/
K – coefficient of compliance with standards,
A – significance coefficient,
R b – basic indicators,
P i is the actual value of the MPE and MPD indicators.
At K i< 1 наблюдается низкий уровень работы предприятия и оно должно быть остановлено.
Zoological examination of the design of an installation, workshop or enterprise is carried out in accordance with the Law of the Russian Federation “0b for the protection of the natural environment”. The examination is carried out by the Ministry of Environmental Protection, the Ministry of Health, and the Sanitary and Epidemiological Supervision Authority.
The project must ensure the capture, recycling, neutralization of harmful substances and waste, or the complete elimination of emissions of pollutants.
^ SCALE TRANSITION AND SIMULATION
There are three main types of process modeling:
1/ physical,
2/ mathematical,
3/ elemental.
1/ ^ Physical modeling
According to this method, the study of the process with the processing of experimental data is sequentially carried out on physical models: laboratory /glass, capacity up to 1 l/, pilot /metal, up to 100 l/, semi-industrial /up to 0.5 m 3 /, industrial /5 m 3 or more/. The method is very cumbersome and time-consuming, but provides reliable results.
Physical modeling is based on similarity theory.
Definition. Phenomena similar to each other are called systems of bodies,
A/ geometrically similar to each other;
B/ in which processes of the same nature occur;
B/ in which quantities of the same name characterizing phenomena are related to each other as constant numbers
X´ = a x · x´´ /10/
Where a x is the similarity constant.
The principle of “similarity” itself was known to mankind in ancient times (a clear example is the Egyptian pyramids). However, the theory of similarity was formed only in the 20th century. The theory is based on three theorems.
/Braines Ya.M. Similarity and modeling in chemical and petrochemical technology. – M.: Gostoptekhizdat, 1961. – 220 p./
^ 1st theorem. Joseph Bertrand, French mathematician, 1848
– For similar phenomena, the similarity indicators are equal to one or the similarity criteria are numerically the same.
/Similarity indicator is a complex of similarity constants, similarity criterion is a dimensionless complex of quantities/.
^ 2nd theorem. T.A. Afanasyeva-Erenfest, 1925, father. mathematician.
– A system of equations that is literally the same for a group of similar phenomena can be transformed into a criterion equation.
^ 3rd theorem. M.V. Kirpichev, A.A. Gukhman, 1930, father. scientists.
– For similar phenomena, similarity criteria, composed of unambiguity conditions, are numerically the same.
^ Uniqueness conditions include:
a/ geometric dimensions of the system;
B/ physical constants of substances;
B/ characteristic of the initial state of the system;
Г/ state of the system at its boundaries /boundary condition/.
Thus, the application of similarity theory to process research and development is as follows.
Drawing up a complete mathematical description of the process, i.e. derivation of the differential equation and setting conditions for uniqueness.
Carrying out such a transformation of the differential equation and uniqueness conditions, determining similarity criteria and the general form of the criterion equation / equation analysis method/.
Determination experimentally using models of a specific type of criterion equation /physical modeling/.
For complex processes, when it is not yet possible to create a differential equation, similarity criteria are obtained based on dimensional analysis method quantities influencing the process /theorems of Bertrand and Buckingham/. For example, criteria for mechanical mixing were obtained using this method.
There are geometric, hydrodynamic, thermal, diffusion and chemical similarities.
^ Geometric similarity taken into account by simplexes "G", for example, the ratio of pipeline length to diameter.
Hydrodynamic similarity is studied in a hydraulics course using the example of a similar transformation of the Navier-Stokes equation. Thermal and diffusion similarity are considered in the PAPP discipline.
Let us recall the criterion equation of hydrodynamics:
Where 
– homochrony criterion, takes into account unsteady fluid movement;
– Froude criterion, takes into account gravity;
– Euler criterion, takes into account hydrostatic pressure forces;
– Reynolds criterion, takes into account the forces of internal friction.
2/ ^ Math modeling
Methods of similarity theory are also used when using other types of modeling, in which the modeling processes differ from those being modeled in physical nature. The most important of them is math modeling, in which various processes are reproduced on electrical models - electronic computers /computers/.
According to R. Franks, the general scheme of mathematical modeling includes seven stages / Franks R. Mathematical modeling in chemical technology. – M.: Chemistry, 1971. – 272 p./.
Formulation of the problem.
Determination of the fundamental laws that govern the mechanism of the phenomena underlying the problem.
Based on the selected physical model, a system of corresponding mathematical equations is written in relation to the problem being solved.
A natural arrangement of equations is carried out using
constructing a block information flow diagram. Diagram
reflects the connection diagram of individual stages of the technological process.
One of several possible ways to solve the system of equations /models/ is selected, for example, logical, analytical, numerical using a computer.
Solution /model analysis/.
Study and confirmation of the results obtained when solving a mathematical model /checking the adequacy of the model/.
Mathematical modeling is much cheaper than physical modeling, it allows you to solve issues of automatic control and optimization of processes, to study a process with an incomplete mathematical description / cybernetic problem /.
3/ ^ Elemental modeling
In this simulation, the process is studied on the elementary cell of an industrial apparatus, and the apparatus itself is then assumed to consist of hundreds and thousands of such cells. For example, the heat exchange on one tube of the apparatus is being studied, and the heat exchanger will consist of 1000 such tubes. The method is used for filtration processes, heat exchange, catalytic cracking, etc., and allows laboratory data to be transferred to industry in the shortest possible time.
^ HYDROMECHANICAL PROCESSES
In food production, many processes lead to the formation of heterogeneous mixtures, which are subsequently subject to separation (crystallization, drying, etc.).
A task of the opposite nature is often encountered: from substances in different states of aggregation, it turns out to be necessary to obtain a mixture /mixing, stirring/.
The solution to both the first and second problems relates to the field of hydromechanical processes.
Classification
In hydromechanical processes, heterogeneous systems are used. The latter consist of at least two phases:
A/ internal or dispersed phase, in a finely crushed state;
B/ external phase or dispersion medium surrounding particles of the internal dispersed phase.
There are different systems.
Gas – solid: a/dust, particle diameter 5-50 microns,
/For comparison: the size of cosmic dust is 0.1–1 microns/.
Gas – liquid: a/ fog 0.3–3 µm; b/ foam.
Liquid – solid: a/ coarse suspensions, > 100 µm,
B/ colloidal solutions,< 0,1 мкм.
Liquid – liquid; a/ emulsions.
1/ Separation of heterogeneous gas systems.
2/ Separation of liquid heterogeneous systems.
3/ Fluidization.
4/ Stirring.
In all hydromechanical processes, particles move in a gas or liquid medium. The study of the laws of this movement is an important task of hydrodynamics. Some general concepts and patterns of particle motion are discussed below.
^ Movement of bodies in liquids
Defining size
The determining size of a solid particle of arbitrary shape is taken to be the equivalent diameter of a spherical particle having the same mass /M/ and volume /V/.
/12/
Where 
– solid particle density, kg/m3.
Flow modes
To estimate the external flow around a solid particle, the Reynolds number is used:
/13/
Where 
– density and viscosity of the medium.
Regions are distinguished.
Laminar flow, Re< 2 /0,1 по другим данным/.
Transition region, 2 /0.1/< Re < 500.
Turbulent flow, Re > 500.
Particle sedimentation in a gravity field
When a particle settles in a stationary medium, after a short period of time (from a second to a fraction of a second), a balance of forces is established and the movement of the particle becomes uniform.
– The speed of uniform motion of a particle with a balance of forces acting on it is called deposition rate.
In the ideal case, the action of forces on a single spherical particle during deposition in a stationary medium is shown in Fig. 1.
Main tasks processing industry and the Russian Federation are the comprehensive processing of agricultural raw materials, increasing the volume of products produced, improving their quality, as well as expanding the range.
Solving these problems at large processing enterprises is possible provided that modern high-tech equipment is used.
Processing industries use a wide variety of equipment and technology.
Classification of processing equipment carried out according to the following criteria:
By the nature of the effect on the processed product;
work cycle structure;
degree of mechanization and automation;
the principle of combination in the production flow;
functional sign.
In addition to the listed characteristics, each type of equipment has specific characteristics.
Depending on the nature of the impact on the product being processed, technological equipment is divided into devices and machines. Heat, mass transfer, physico-chemical, biochemical and other processes are carried out in the apparatus, as a result of which a change in the physical, chemical properties and physical state of the processed product occurs. A characteristic feature of the apparatus is the presence of a reaction space or chamber.
The machines exert mechanical influence on the product, as a result of which its shape and size change. A design feature of machines is the presence of moving executive (working) bodies. In some cases, technological equipment is a combination of a machine and an apparatus, since mechanical, physicochemical and thermal effects are simultaneously carried out in it.
According to the structure of the operating cycle, equipment can be periodic, semi-continuous and continuous. In batch equipment, the product is exposed for a certain time, after which it is discharged.
In semi-continuous (cyclic) equipment, the product is loaded and acted upon continuously throughout the entire operating cycle, and unloaded at certain intervals.
In continuous equipment, loading, processing and unloading of product are carried out simultaneously.
During operation, technological equipment performs not only basic (grinding, mixing, cooking, etc.), but also auxiliary (loading, moving, control, unloading, etc.) operations. Depending on the degree of mechanization and automation of these operations, equipment can be non-automatic, semi-automatic and automatic. In non-automatic (simple) equipment, auxiliary operations, as well as some of the main operations, are performed manually.
In semi-automatic equipment, all technological and most auxiliary operations are performed without the participation of a worker. Transport and control operations, starting and stopping the machine remain manual.
In automatic equipment, all basic and auxiliary operations are performed by the equipment without human intervention. A special case of automatic equipment are cybernetic machines (robots).
Based on the principle of combining technological equipment in the production flow, individual units are distinguished (perform one operation); units or complexes (perform sequentially various operations); combined (perform a complete cycle of operations) and automatic flow systems (perform all technological operations in a continuous flow).
One of the features on the basis of which classification of equipment is possible is the commonality of the functions it performs in the process of processing raw materials or semi-finished products. Based on this criterion, the following large groups and subgroups of equipment are distinguished (Table 1):
1. Equipment for preparing raw materials for processing:
1.1) for cleaning and sorting;
1.2) washing and moistening;
1.3) grain peeling.
2. Separation machining equipment:
2.1) for crushing and grinding;
2.2) separation of grain grinding products;
2.3) separation of suspended solid and colloidal particles from liquid heterogeneous systems;
2.4) separation of the liquid phase.
3. Joint machining equipment:
3.1) for mixing in order to obtain liquid, bulk, dough-like semi-finished products and finished products;
3.2) molding by extrusion, stamping.
4. Equipment for carrying out heat and mass transfer processes:
4.1) for carrying out thermal processes;
4.2) carrying out mass transfer processes;
4.3) drying and dehydration;
4.4) boiling and boiling;
4.5) baking and roasting;
4.6) cooling and freezing.
5. Equipment for carrying out microbiological processes:
5.1) for malting;
5.2) obtaining biomass;
5.3) obtaining secondary metabolites.
6. Equipment for finishing operations:
6.1) for sanitary treatment of containers;
6.2) dosing and capping;
6.3) inspection and labeling.
The above classification applies to a greater extent to food production equipment and does not sufficiently characterize individual groups of equipment for processing agricultural products. This is explained by the fact that in a number of technological processes for processing agricultural raw materials, equipment is used that is very specific in purpose, design and principle of operation and requires a separate approach for its classification. An example is equipment for pre-slaughter immobilization of animals, slaughter of animals and poultry, blood collection, skinning, so it is more convenient to classify equipment for processing agricultural products depending on the technological process being performed.
Based on this principle, equipment for processing agricultural products is divided into:
1) equipment for processing crop products;
2) equipment for processing livestock products.
In turn, the second group is divided into equipment for meat processing and equipment for milk processing. Meat processing equipment includes the following groups:
livestock and poultry slaughter line;
equipment for primary processing of pig carcasses;
processing of livestock and poultry slaughter products;
mechanical processing of raw meat;
heat treatment of raw meat;
packaging of meat and meat products.
With a more detailed classification, for example, equipment for the mechanical processing of raw meat, it is divided into equipment for grinding meat and lard, mixing raw meat, salting meat and molding meat products.
Equipment for milk processing according to the general classification is divided into equipment:
for transportation, reception and storage of milk;
mechanical processing of milk;
heat treatment of milk;
butter production;
cottage cheese production;
cheese production;
ice cream production;
production of condensed dairy products;
production of dry dairy products;
filling and packaging of milk and dairy products.
As an example, we can also cite the general classification of equipment for grain processing enterprises. Based on the functional characteristics and method of influencing the product, it is divided into separating, weight-dosing, mixing, grinding, forming, as well as equipment for hydrothermal treatment (HTT) of grain.
Mechanical equipment for food processing plants
industry belongs to the class of technological machines.
Mechanical equipment is designed to perform
technological operations for primary food processing
products in order to change their properties (structure, shape,
sizes, etc.)
Classification of mechanical equipment
The technological machine isdevice consisting of a motion source, transmission
mechanism, actuator and auxiliary
elements combined into a single whole by a frame or body.
The auxiliary elements of the technological machine include
control and regulation units, devices providing
safety of operating personnel, loading and
unloading devices, etc.
frame
Remote control
M
P.m.
Them
.
bed
Classification of mechanical equipment
Mechanical equipment for food processing plantsindustries can be classified:
By
By
By
By
functional purpose;
number of operations performed;
work cycle structure;
degree of automation, etc.
Classification of mechanical equipment
By functional purpose:sorting and calibration;
detergent;
cleansing;
grinding and cutting;
kneading and mixing;
dosing and molding;
pressing.
Classification of mechanical equipment
Sorting equipment is used for sorting,calibration and sifting of bulk products, vegetables, fruits and
etc.
Washing equipment – for washing vegetables and other raw materials.
Cleaning equipment – for cleaning root tubers,
fish.
Chopping and cutting equipment – for grinding,
crushing, wiping, cutting food products.
Kneading and mixing equipment – for kneading dough,
mixing minced meat, beating confectionery mixtures, etc.
Dosing and forming equipment – for forming cutlets,
dividing butter into portions, rolling out dough, etc.
Pressing equipment - mechanisms for obtaining juice from
fruits and berries, pasta production, etc.
Classification of mechanical equipment
By the number of operations performed:Single-operational – performing one technological process
operation (potato peeler - peeling potatoes).
Multi-operational – performing the technological process,
consisting of several technological operations
(dishwasher - wash dishes with hot water and
detergent solution, pre-rinse,
final rinsing, sterilization).
Multi-purpose – performing several technological
processes using alternately connected replaceable
actuators (universal kitchen machines
with replaceable working bodies).
Classification of mechanical equipment
According to the structure of the work cycle:Batch machines in which loading, processing and
The product is unloaded one by one, i.e. start
processing of the next portion of the product is possible only after
how the previously processed material will be unloaded from the working chamber
product. (potato peelers, dough mixers, beaters
cars, etc.)
Continuous machines in which loading processes,
processing and unloading of the product in steady state
coincide in time, i.e. the product is continuously promoted from
loading device into the working chamber, moves along it
and at the same time exposed to the working bodies, after
which is removed through the unloading device, i.e. new portions
product are fed into the machine before processing of the previous and
accordingly, its operating time will be reduced (meat grinders,
vegetable cutters, wipers, sifters, etc.)
Classification of mechanical equipment
According to the degree of automation of technological processes,performed by the machine:
Non-automatic machines. They have technological
operations (feeding products into the working chamber, removing from it
finished products, control over product readiness)
performed by the operator servicing the machine.
Semi-automatic machines. Basic
technological operations are carried out by machine, manually
only auxiliary operations remain (for example, loading and
unloading products).
Automatic machines. All technological and
auxiliary operations are performed by machines. Such
machines can be used in the technological process
autonomously or as part of production lines.
10. Productivity, power and efficiency of the machine
Process performancemachine is its ability to process
a certain amount of product per unit
time (kg/h, pcs./s, m³/h, t/day, etc.).
11. Productivity, power and efficiency of the machine
Theoretical productivity (Qt) isquantity of production that the machine can
release per unit of time with uninterrupted and
continuous operation in stationary mode.
B
E
Q B z
,
T
T P TT
where B is the quantity of products produced by the machine per worker
cycle (kg, pcs., t, etc.);
z – number of working cycles per unit of time;
Тr – machine operating cycle (h, s, day, etc.);
E – capacity of the working chamber (m³);
Тт – technological cycle of the machine (h, s, day, etc.)
(Тт=tз+to+tв, where tз – loading time, to – time
processing, tв – time of unloading of products from the machine).
12. Productivity, power and efficiency of the machine
The technological cycle of a machine is calledresidence time of the processed object in
technological machine, during which he
undergoes processing from the initial state to
final according to the technology of this process.
The operating cycle of a machine is called the interval
time between two consecutive moments
output of finished product units.
13. Productivity, power and efficiency of the machine
Technical (valid)productivity (Qtech.) is average
quantity of products that a machine produces in
over a unit of time under operating conditions in
in accordance with technological requirements
process. Technical and technological
productivity are related by the ratio:
QTECH. K T.I.QT
where Kt.i. – coefficient of technical utilization of the machine;
14. Productivity, power and efficiency of the machine
Machine technical utilization rate:KT.I.
T MASH.
T MASH. T T.O. T OTK.
where is Tmash? - time of effective operation of the machine in a stationary
mode (h);
Tt.o. – time required for maintenance and commissioning
machines in stationary mode (losses of the first kind) (h);
Totk. – time required to restore functionality
machine and putting it into stationary mode after failure
(losses of the second kind) (h.).
15. Productivity, power and efficiency of the machine
Operating performance (Qex.)is the productivity of the machine operated at
this enterprise, taking into account all worker losses
time.
QEX. K O.I.QT
where Ko.i. – coefficient of total machine utilization, taking into account all
loss of computer time (including machine downtime due to
organizational reasons), it is impossible to calculate accurately.
16. Productivity, power and efficiency of the machine
Machine power is the energy thatsupplied to the machine per unit time and
characterizes the speed of work.
Engine power must make up for losses
it in the engine itself, in the transmission mechanism, on
the working shaft transmitting movement to the workers
authorities, and be sufficient for the worker
the organ performed work at a given speed.
17. Productivity, power and efficiency of the machine
The total power that needs to be transferred toactuator input shaft,
is determined taking into account losses in the mechanism itself and
gears:
,
PO
PD PTR
,
where Рд – power expended on propulsion
working body;
Ptr – power expended on movement
processed object;
- efficiency, taking into account power losses during its transmission from
the engine shaft to the working element.
18. Productivity, power and efficiency of the machine
During forward movement of the working body:P.D.F.O. R.O.
PTR FO. ABOUT.
where Fр.о. – force applied to the working body, N;
p.o. - linear speed of movement of the working body, m/s;
Fo. - force applied to the processed object, N;
o - linear speed of movement of the processed object
under the action of the working body, m/s;
19. Productivity, power and efficiency of the machine
During rotational movement:P.D.M.R.O. R.O.
PTR M O.O.
where Mr.o. - torque applied to the working element, N m;
p.o. - angular speed of movement of the working body, rad/s;
Mo. - torque applied to the object being processed, N m;
O
- angular velocity of movement of the processed object under
action of the working body, rad/s.
20. Productivity, power and efficiency of the machine
If the electric motor is selected with insufficient power incompared with the expected load, this will lead to
incomplete use of the machine (apparatus) or
overloading individual parts of the electric motor and
its premature failure.
If the electric motor power exceeds
expected load, technical and economic
the machine's performance will decrease (the initial
the cost of the electric drive, the efficiency will decrease, etc.).
21. Productivity, power and efficiency of the machine
Efficiency of a technological machine (apparatus)is the ratio of useful work (useful
energy expended) to all work done
(energy expended).
Hence,
coefficient
useful
action characterizes the amount of losses and the amount
useful energy expended and is one of
criteria for the degree of transformation perfection
electrical (thermal, etc.) energy in
mechanical and vice versa.
22. Productivity, power and efficiency of the machine
Energy losses in machines and deviceshappen:
in the technological process;
when the mechanisms are idling;
in the presence of friction forces in kinematic pairs;
as a result of energy dissipation during
deformation and vibration of parts and machines;
when released into the environment, etc.
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