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Shell and tube heat exchangers

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Shell and tube condensers Shell and tube condensers
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128 000.00 грн
  • Working temperatures (°C): -60...+ 350
  • Nominal pressure (MPa): 0.6; 1.0; 1.6; 2.5
Shell and tube evaporators Shell and tube evaporators
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  • Working temperatures (°C): -60...+ 350
  • Nominal pressure (MPa): 0.6; 1.0; 1.6; 2.5
Shell and tube coolers Shell and tube coolers
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90 000.00 грн
  • Working temperatures (°C): -60...+400
  • Nominal pressure (MPa): 0.6; 1.0; 1.6; 2.5; 4.0
Shell and tube heaters Shell and tube heaters
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90 000.00 грн
  • Working temperatures (°C): -60...+400
  • Nominal pressure (MPa): 0.6; 1.0; 1.6; 2.5; 4.0
Tubeintube heat exchanger liquidliquid Tube-in-tube heat exchanger (liquid-liquid)
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80 000.00 грн
  • Working temperatures (°C): -60...+ 250
  • Nominal pressure (MPa): 0.6; 1.0; 1.6

Shell and tube heat exchangers

A shell-and -tube heat exchanger is a type of recuperative type heat engineering apparatus in which heat exchange occurs between two immiscible media separated by the walls of the passage channels. It owes its name to the peculiarities of its design, in which a pipe (or more often a bundle of pipes), along which one coolant moves, is inside a pipe of a larger diameter, called a casing, through which another coolant is pumped. The system of internal heat exchange pipes is called the tube (in-tube) space, and the capacity inside the casing is called the shell-and-tube heat exchanger shell. Heat transfer between the two media in it occurs through the walls of the inner tube or tubes of the inner bundle. A large casing pipe also serves as the basis for the outer casing of such a heat exchanger.

Device and principle of operation

The classic design is considered to be a one-way shell-and-tube heat exchanger. In it, the inner tube space is formed by a bundle of tubes (3), sandwiched between two tube sheets (2), made according to the diameter of the casing, and hermetically fixed in it. The three-pipe space is closed by two end caps (4) with attached pipes (inlet and outlet, respectively). The in-tube coolant from the supply line through the inlet pipe enters the space under the first cover, is distributed by the tube sheet along individual tubes in the bundle, passes through them, enters the space under the second cover, and exits through its outlet pipe. The annular space for the second medium is formed by the side walls of the casing (1) and the back sides of the tube sheets (2). The inlet and outlet pipes of the intertube coolant, as a rule, are located on the casing body. To increase the thermal head and intensify heat transfer, heat carriers are usually passed through the pipe and annular spaces in opposite directions, the so-called. Countercurrent.

Схема одноходового кожухотрубного теплообменника

Fig. 1 Diagram of a one-way shell-and-tube heat exchanger

Варианты конструкции трубных решеток, и соответственно, размещения труб в пучке.

Fig. 2 Variants of tube sheet design and, accordingly, tube placement in a bundle.

In terms of spatial orientation, shell-and-tube heat exchangers can be:

  • vertical - more compact in terms of the occupied area, they effectively work with vapor-gas media, including as condensers, since the vertical orientation facilitates the drainage of condensate;
  • horizontal - they work more efficiently with liquid media, with a horizontal orientation it is easier to implement structures of very large dimensions and thermal power.

Other types of shell and tube heat exchangers

The disadvantage of a one-way shell-and-tube heat exchanger is the relatively low speed of movement of the coolant in the annular space (inside the wide casing), which entails a relatively low intensity of heat exchange and low heat transfer power.

To intensify heat exchange and increase the transmitted heat power, a multi-pass design of a shell-and-tube heat exchanger is used. In it, the space inside the casing is divided by partitions (6), which simultaneously serve as intermediate supports for the tube bundle, which form transverse “passages” for the annular medium. The cross-section of the transverse passages is made significantly smaller than that of the direct-flow one-pass casing, due to which the speed of passage of the intertubular medium through the heat exchanger increases. Transverse baffles also cause the formation of strong turbulence (mixing) of the annular medium, which intensifies its heat transfer. In turn, for the formation of turbulence of the coolant pumped through the in-tube space, instead of smooth-walled, specially profiled, so-called helicoid tubes are used.

Схема многоходового кожухотрубного теплообменника

Fig. 3 Diagram of a multi-pass shell-and-tube heat exchanger

Пример профилированной геликоидной трубки

Fig. 4 Example of a profiled helicoidal tube

If the temperature gradient between two heat exchange media is significant (50 degrees C or more), then the difference in the coefficients of thermal expansion of the shell-and-tube heat exchanger parts can literally break their connections, disrupting the tightness of the circuits and creating a threat of mixing of the heat exchange media. In such cases, schemes of shell-and-tube heat exchangers with temperature compensation mechanisms are used:

a) - with a lens compensator;

b) - with a floating head;

c) - with U-shaped tubes.

Схемы кожухотрубных теплообменников с механизмами температурной компенсации

Fig. 5 Schemes of shell-and-tube heat exchangers with temperature compensation mechanisms

Separately, there is a two-tube heat exchanger of the “tube-in-tube” type. Apparatuses of this type consist of several elements (sections) connected in series, formed by two pipes, one of which (of smaller diameter) is located inside the other, with the presence of a sufficient through annular gap that forms the annular space. The inner pipes (1) are interconnected by bends (3), and the outer pipes (2) are interconnected by side pipes (4). In such a system, one coolant is pumped through the inner pipe system, and the second through the annular gap system of the annular space. Devices of this type are designed to operate at low flow rates of heat transfer agents, high operating pressures and high pumping rates of heat exchange media.

Схема теплообменника «труба в трубе»

Fig. 6 Scheme of a pipe-in-pipe heat exchanger

Advantages of shell and tube heat exchangers

The design of shell and tube heat exchangers is primarily characterized by a very high flexibility and the ability to adapt to a wide variety of technological or production conditions, needs and processes. There is a possibility:

  • to manufacture them in a wide variety of flow cross-sections for in-pipe and inter-pipe media;
  • manufactured with thick-walled (hardened) heat exchange tubes and various temperature compensation mechanisms;
  • use a variety of construction materials - heat-resistant, acid-resistant, cold-resistant, etc.

Due to this, shell-and-tube heat exchangers are able to operate in a very wide range of operating temperatures and pressures, including chemically aggressive, abrasive, contaminated media. An important factor is the ability to implement a multi-sectional scheme to ensure almost any of its performance (thermal power).

In comparison with other types of heat exchangers, among other things, shell-and-tube heat exchangers differ:

  • simplicity in engineering (technical) implementation;
  • ease of maintenance and good maintainability;
  • high technical reliability, long service life.

Scope of application

With all their indisputable advantages, it should be recognized that shell-and-tube heat exchangers are still characterized by high metal consumption, cumbersomeness and relatively large dimensions. Therefore, the scope of their application, first of all, is a variety of industrial technological processes with severe operating conditions, characterized by high operating temperatures and pressures, chemically aggressive media, which require a very high thermal power or productivity. Functionally shell-and-tube heat exchangers can serve as powerful and highly efficient: heaters, coolers, condensers, evaporators.

Shell and tube heat exchanger specifications

As for any heat exchanger, the main technical parameter for a shell-and-tube heat exchanger is the effective heat exchange area (in m 2 ), which determines its thermal power (performance).

Other important technical characteristics of a shell-and-tube heat exchanger are:

  • materials for the manufacture of pipes and casing, which determine the list of working environments with which it is possible to use;
  • Operating temperature range;
  • maximum pressure in the tubular and annular spaces;
  • parameters of access to maintenance and repair (collapsible or non-collapsible);
  • external dimensions.

Calculation of a shell-and-tube heat exchanger

The calculation and design of shell-and-tube heat exchangers is carried out by the heating engineers of the manufacturer, in accordance with the customer's specifications. To accomplish this design, the customer should provide the manufacturer with a number of critical technical parameters that characterize the future operating conditions of the shell and tube heat exchanger. These critical parameters include:

  • the type of working media for the pipe and annular space;
  • nature of application (as a heater, cooler, evaporator, condenser);
  • required thermal power (performance);
  • mass flow rate of working media;
  • inlet and outlet temperatures for each of the working media;
  • maximum pressure for each of the working media.

Advantages of heat exchangers manufactured by OPEKS Energosystem

OPEKS Energosystems has many years of experience in the industrial manufacture of shell-and-tube heat exchangers of various types, designs and purposes, for the most difficult operating conditions, owns a modern automated machine park, as well as experienced, qualified personnel of engineering and working specialties. We implement the entire accumulated amount of experience and knowledge in our modern products, which are objectively characterized by:

  • high quality and design accuracy, strictly in accordance with the stated operating conditions;
  • the use of the most modern technical solutions and materials;
  • impeccable workmanship;
  • very long warranty and estimated service life;
  • the availability of effective technical support and service programs for our heating equipment.

Today we have a large number of already implemented projects of shell-and-tube heat exchangers, and we can confirm our impeccable business reputation with numerous real positive reviews from our customers.

The principle of operation of a shell-and-tube heat exchanger manufactured by OPEKS Energosystem

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Shell and tube heat exchangers

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