CC BY
7Martynov D. Y.
Candidate of Engineering Sciences, Associate Professor, Russian State Agrarian University - Moscow Timiryazev Agricultural Academy
Novichenko A.I.
Candidate of Engineering Sciences, Associate Professor, Russian State Agrarian University - Moscow Timiryazev Agricultural Academy
Martynov V.Y.
research officer,
Open Company "Scientific-production Ekorintekh enterprise"
Kuchinova I. V.
research officer,
Open Company "Scientific-production Ekorintekh enterprise"
Puzenko E.E.
research officer,
Open Company "Scientific-production Ekorintekh enterprise"
Мартынов Дмитрий Юрьевич
кандидат технических наук, доцент Российский государственный аграрный университет - МСХА
имени К.А. Тимирязева Новиченко Антон Игоревич кандидат технических наук, доцент Российский государственный аграрный университет - МСХА
имени К.А. Тимирязева Мартынов Виктор Юрьевич научный сотрудник, ООО «НПП «Экоринтех» Кучинова Инна Викторовна научный сотрудник, ООО «НПП «Экоринтех» Пузенко Екатерина Евгеньевна научный сотрудник, ООО «НПП «Экоринтех»
OPTIMIZATION AND COSTS REDUCTION OF THE PRODUCTION PROCESSES WITH APPLICATION OF NEW TECHNOLOGICAL
SOLUTIONS AND HEAT EXCHANGERS ОПТИМИЗАЦИЯ И СНИЖЕНИЕ ЗАТРАТ ПРОИЗВОДСТВЕННЫХ ПРОЦЕССОВ С ПРИМЕНЕНИЕМ НОВЫХ ТЕХНОЛОГИЧЕСКИХ РЕШЕНИЙ И ТЕПЛООБМЕННЫХ АППАРАТОВ
Summary: The article presents possible ways of modernization of the column heat exchangers for the food and chemical industry in the technological process of rectification of liquid mixtures that require heat processing circuit and produce a valuable end product. The presented version of the system to external automated monitoring of hydrodynamic flow regime inside the column thin film evaporator and installation of heating the liquid mixture, which allows to reduce energy costs by 10% and reduce duration by 5 times in comparison with rotary machines of the same size and volume.
Key words: equipment for food industry, heat exchangers, thin-film evaporators, distillation equipment.
Аннотация: В статье представлены возможные пути модернизации колонных теплообменных аппаратов для пищевой и химической промышленности в технологических процессах ректификации жидкой смеси, которые требуют тепловой схемы переработки и получения ценного конечного продукта. Представлен вариант системы внешнего автоматизированного мониторинга гидродинамического режима потока внутри колонны тонкопленочного испарителя и установки нагрева жидкой смеси, которая позволяет снизить затраты энергии на 10% и сократить продолжительность обслуживания в 5 раз по сравнению с роторным аппаратам такого же размера и объема.
Ключевые слова: оборудование для пищевой промышленности, теплообменные аппараты, тонкопленочные испарители, ректификационное оборудование.
In many ways, obtaining financially valuable and valuable from the customer's point of view products can be achieved, according to [1, 2, 3], in the frame-
work of a multi-stage thermo-biological or thermo-chemical processing. As a valuable final products may be, for example, the dairy products which are demand-
ing to thermal regime of processing, obtained by [2, 3, 4] within the food production cycle. Thus, according to [6, 7, 8, 9], columnar, film evaporators can be one of the basic elements of the overall structure of the food or chemical production. In spite of the large consumption of materials and on a large dimensions of the columnar, film evaporator, these evaporators have the following advantage: the possibility of almost uniform heating of the entire volume of the liquid under separation, ending up with obtaining a valuable end product with use of such thermo-hydraulic and ther-modynamic conditions which allowing to keep the product in its entirety. The main function of modern columnar, film evaporators is the formation of an effective hydrodynamic flows and regimes along its inner, externally heated walls , according to [10, 11], intensifying heat and evaporation separated liquid, and partially or completely preventing resinification and thermal destruction of thermally degradable products on the internal surface of this apparatus. Exemplary, comparative characteristics of various types of heat
exchangers - evaporators according to [2, 6] are presented in Table 1.
According the data shown in Table 1, the columnar, film evaporator can be evaluated as being sufficiently productive given nominal heat transfer coefficient in the reference mode and cheap apparatuses, which are practically no replaceable in the field of specialization - the rectification of the thermally unstable liquid medias. At the same time, according to [2, 3, 6], columnar, film evaporators can be simplisti-cally divided in two types:
- the rotary columnar, film evaporators, in which a uniform distribution of heated fluid along the vertical cylindrical wall is effected by means of spinning of the rotor;
- the columnar, film evaporators where the rotor is absent, so the regular distribution of the heated fluid along the cylindrical vertical walls is effected in other ways, via the nozzles, guiding rail and other distribution devices.
Designation and name Mode The surface area of the heat exchanger, m2 Parameters of liquid media Total weight of the heat exchanger (including stainless steel), kg The heat transfer coefficient in the reference mode, W / (m2 • K)
Range of operating temperature, °C The pressure in the working part of the apparatus, max P, atm.
Columnar membranous evaporators
Columnar membranous evaporator Demountable 1,55 from 0 till +250 2,5 300 1000-1200
"Tube in tube" Heat exchangers
Tubes from 10 till 100 from -30 till +300 from 10 till 80 10000 (4800) 1400
Air cooling Heat exchangers
Air cooling heat exchangers Ribbed tubes from 85 till 540 from -40 до +400 from 6 till 100 12000 (5000) 65
Pipe Heat exchangers
Pipe heat exchangers With stationary grids from 1 till 960 from -30 till +350 from 6 till 40 3410 (2700) 1200
Pipe heat exchangers With floating head from 10 till 1240 from -30 till +450 from 16 till 80 4700 (3100) 830
Twisted pipe from 100 till 600 from -200 till +475 from 16 till 200 3600 (3400) 1150
Plate Heat exchangers
Demountable from 1 till 800 from -20 till +150 10 1900 (940) 1750
Semi- demountable from 31 till 300 from -20 till +200 16 2755 (1370) 1900
Non- Demountable from 100 till 500 from -100 till +300 25 2200 (1200) 1800
Special from 100 till 550 320 2400 (1800) 1600
2000
Spiral Heat excjangers
Steel Tape from 10 till 100 from -20 till +200 10 6000 (3500) 1400
Plate-Ribbed Heat exchangers
Ribbed plate 16 from -200 till +200 3 1680 (1600) 850
Heat exchangers from nonmetals
- Graphite from 1 till 120 from 10 till +150 5 6000 (2400) 1000
- Fluoroplastic from 1 till 40 till 150 2 1850 300
According the data shown in Table 1, the columnar, film evaporator can be evaluated as being sufficiently productive given nominal heat transfer coefficient in the reference mode and cheap (considering the total mass) apparatuses, which are practically no replaceable in the field of specialization - the rectification of the thermally unstable liquid medias. At the same time, according to [2, 3, 6], columnar, film evaporators can be simplistically divided in two types:
• The rotary columnar, film evaporators, in which a uniform distribution of heated fluid along the vertical cylindrical wall is effected by means of spinning of the rotor;
• The columnar, film evaporators where the rotor is absent, so the regular distribution of the heated fluid along the cylindrical vertical walls is effected in other ways, via the nozzles, guiding rail and other distribution devices.
At the same time, the rotary columnar, film evaporators have some drawbacks which complicate their work:
1. When driving and rotating the rotor in a volume of liquid there occur the pressure differences between the edge of the rotor blades and the inner wall surface, which are accompanied with unevenly distributed turbulent flow and excess fluid compression, which leads to the additional thermal and electric energy consumption and in some cases to the resinifica-tion and the temperature' degradation of the liquid on the inner wall of the rotary columnar, film evaporator, which is the loss of the valuable part of the final product.
2. The presence of the spinning rotor in a columnar, film evaporator which is operating under excessive pressure or in a vacuum, requires: additional financial costs for the making of high-quality insulation system between the moving rotor and the fixed evaporator body, as well as the costs for additional service, including one associated with partial or complete dismantling of the columnar, film evaporator and with the replacement of worn out components and mechanisms (which also results in downtime and additional losses of financial assets).
The columnar, film evaporator without he rotor are generally more easy to maintain, less energy con-
suming, but requires the creation of the effective systems of the automation and regulation for the guiding rail and the nozzles for creating the hydrodynamic and hydraulic conditions, which would allow to separate the liquid mixtures with maximum quality and without losses of final product (e.g. such as water and capro-lactam in the cycle of production of caprolactam and nylon).
Thus for in order to get moved along the inner surface of the evaporator the liquid film with the required characteristics such as thickness and dynamics can be used the guide rails serving for the adjustment of the movement direction of the liquid film and the jet nozzles which carry jet drip irrigation and which press the film with required pressure to the cylindrical walls of the evaporator. The authors developed a conceptual diagram of the layout and operation of the columnar, film evaporator which is equipped with the guide rails and the jet nozzles adjustable via automation.
The design concept of the column evaporator may include: cylindrical vertical tank (height of 1 meter or more); an outer cylindrical vertical heat exchanger jacket unit parallel to the side wall, and divided into several sections with quick feeding and pumping out the coolant at a certain temperature in/out of each of the sections of thermal jacket in order to create a required temperature regimen on the side wall of the evaporator; the system of the liquid mixture entering, adjustable (by intensity and angle); the system of withdrawal of a portion of the liquid mixture from the walls of the apparatus and re-supply of the liquid mixture through the nozzle; the automated complex which regulates the heating in the sections of the heat exchange jacket, in order to create optimal thermal conditions of heat exchange and to prevent resinification on the walls and thermal degradation of the final product. Internal pressure and the temperature in the column, film evaporator can selected according to particular manufacturing requirements. Possible layout of the column, film evaporator (in a front view) is shown in Fig. 1-a, the vertical sectional view (A-A) Fig. 1-c, and the horizontal section view (B-B) in Fig. 1-d.
a)
Fig. 1 The column, film evaporator contains the elements as follows
b)
c)
1 - input system of the liquid mixture to the column, film evaporator;
2 - outer casing of the heat mass transfer jacket of the column, film evaporator;
3 - inner casing of the column thin film evaporator;
4 - pipes to enter coolant into a heat exchange jacket;
5 - pipes for output of the coolant from the heat exchange jacket;
6 - reinforcing rods for fixing the nozzles and the sensors;
7 - jet nozzles for horizontal mixing of the liquid mixture;
8 - lid of the column, film evaporator;
9 - system of fixing the reinforcing rods on the lid of the column, film evaporator;
10 - lower fixing mechanism for reinforcing rods;
11 - pipe for the output of the liquid product from the column thin film evaporator;
12 - temperature sensors at the inlet of the heat exchange jacket;
13 - temperature sensors at the outlet of the heat exchange jacket;
14 - temperature sensors on the inside wall of the column, film evaporator (at the top of the evaporator);
15 - flow rate sensor (at the top of the evaporator);
16 - flow rate sensor (in the middle of the evaporator);
17 - flow rate sensors (at the liquid mixture's outlet from the evaporator);
18 - temperature sensors on the inside wall of the column film evaporator (at the bottom of the evaporator);
19 - pressure sensor in the interior of the evaporator;
20 - hydraulic seal;
21 - vertical legs.
The process of distillation of the liquid mixture in a column evaporator, as shown in Fig. 1 may be implemented as follows. Through the entry system (1) the liquid mixture is at an angle to the horizontal 0° is injected and guided to the inner wall (3) of the column body film evaporator. Depending on the type of the model liquid and on its processing time the speed of liquid 'supply to the column thin film evaporator can be from 5 to 20 m/sec. Further, the liquid mixture un-
der the influence of gravity acquires a vertically downward component of velocity and enters the receiving -interception device connected to the conductive pipe with nozzle (7). The angle, at which the liquid mixture reaches the receiving- interception device, is determined by its input speed and by the height on which the shut-off devices are located relative to the fluid entering system (1). In this case the receiving-interception device is a wide rectangular orifice with
dimensions of the access opening 100 x 5 mm, which is arranged in the direction of fluid flow and can approach and move away from the wall a distance in the range from 0 to 20 mm and can be rotated at an angle of from 0° to 20° to the vertical axis due to the automatic mechanized device.
The receiving - interception device which acts in the automated regimen, separates liquid mixture flowing along the wall into two parts, where the part of the liquid mixture remains on the wall and the other part is discharged through the receiving - interception device and through the conductive pipe to a nozzle (7)
from which the liquid mixture is displayed in the horizontal direction on the wall below the axis location of the shut-off device. Base distance in height between the receiving - interception device and the nozzle can be selected the interval in 100 mm. The nozzles (7) can be fixed on the housing of the column film evaporator by means of mechanized automated device managed via shifting of vertical wires (not shown on drawings), or the nozzles (7) can be simply welded to the vertical reinforcement rods (6) fixed on the housing in the case of using the standard parameters for the liquid mixture processing.
Fig. 2. Scheme of work column film evaporator
The evaporator has 12 nozzles in total, and the outer side of the wall of the receiving - interception device of the following nozzle (located below), is in contact with the conductive tube of the previous nozzle (located upstream of) the way that the liquid mixture remaining on the wall after passing located above the receiver- interception device can be mixed with the liquid mixture flowing out of the nozzle positioned just below (7) to form an effective micromixing zone and heat transfer between the inner casing (3) and the surface (film flow) of the liquid mixture. The reinforcing rods for fixing the nozzles and sensors (6) are fixed by means of fastening system on the lid of the column, film evaporator (9) and lower automated fastening mechanism for reinforcing rods (10) can be fixed at different heights in the range of 100 mm up and down in a vertical position in order to automatically change the position of nozzles (7) along the vertical axis. To prevent leakage and depressurization of the column, film evaporator, the system of fixture of the reinforcing rods to the lid of the column of the film evaporator (9) and a lower automated mounting
mechanism for reinforcing rods (10), comprise a gasket and a gland, which let the reinforcing rods move in the vertical direction in the range of 0 to 100 millimeters and wherein the internal space of the apparatus is sealed for a long time, without extra maintenance.
After setting, the system of nozzles (7) forms the basic mode of the hydrodynamic flow of the liquid mixture on the wall (3) of the inner casing of the column, film evaporator. At the final stage end (not steamed) liquid product gradually flows down into the container - into the space formed between the inner casing of the column film evaporator (3) and water seal (20), where from uniformly evacuated through the outlet pipe (11) of the column, film evaporator. The hydroseal also collects individual droplets of the liquid mixture, which fall down separated from the film of liquid mixture flowing over the wall (3) and under the action of gravity they are dropping on the hy-droseal. The vapor, retrieved, as a result of evaporation, elapse upwards inside the column, and remove trough the pipe (on the drawing, not shown), in the upper part of the apparatus
Here below is shown the List of the electrical and electronic devices with use of which can be significantly improved energy and economic efficiency of the column thin film.
Conclusion
Thus, by creating a system of external automated monitoring of hydrodynamic flow regime within the column thin film evaporator and of the temperature
settings of the heating of the liquid mixture (treated liquid raw material) and by creating an evaporator (apparatus) without having the rotating parts (rotor blades) with the jet nozzles of a new type is expected to increase capacity (by 5% or more), decrease of the energy consuming (by 10% or more) and reduction of the maintenance time in 5 times as compared with rotary apparatuses of the same size and volume.
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