Shell and tube heat exchanger

Abstract

This utility model relates to heat exchange equipment. The technical result of the proposed shell-and-tube heat exchanger design is increased heat transfer efficiency. This technical result is achieved in the shell-and-tube heat exchanger by installing turbulators inside the tube bundle. These turbulators are made of a plate with alternating petals made of sheet material with inserts in the form of tubes equipped with limiters and rings along which the petals move. A perforated distribution grid is located inside the housing under the rings, the diameter of the holes of which corresponds to the condition dн. <dо<dш,где dн - наружный диаметр труб трубного пучка, м; dо - диаметр отверстия в распределительной решетке, м; dш - диаметр выполненного в виде кольца груза цилиндрической пружины, м.

Description

[0001] The utility model relates to heat exchange equipment that can be used in the energy, nuclear, chemical, petrochemical, metallurgical, biochemical, pharmacological, mechanical engineering, construction and other industries, in environmental processes for the treatment of industrial and municipal wastewater, as well as the purification and utilization of thermal energy from ventilation emissions and flue gases.

[0002] A known design of an industrial shell-and-tube heat exchanger consists of a body (casing) and tube sheets welded to it, in which a tube bundle is fixed; covers are bolted to the tube sheets, and the joint between the covers and the tube sheets is sealed with gaskets. The covers are equipped with inlet and outlet pipes for one coolant moving in the tubes of the tube bundle, and the body (casing) is equipped with inlet and outlet pipes for the second coolant moving in the annular space [Machines and apparatus for chemical production: A textbook for universities / edited by A.S. Timonin. - Kaluga: N.F. Bochkareva Publishing House, 2008, 872 p.: pp. 473, 474].

[0003] The factors that prevent the desired technical result from being achieved include the gradual buildup of thermal deposits on the inner and outer side heat-transfer surfaces of the pipes, in the form of soot, scale, salt scale, and degradation products. This requires periodic shutdowns and cleaning of the outer and inner surfaces of the pipes and tube bundle from the aforementioned deposits. The thermal boundary layer near the wall also negatively impacts heat transfer intensity, limiting the intensity of the heat transfer process. All of the above indicates an overall decrease in heat transfer efficiency.

[0004] A shell-and-tube heat exchanger is known, consisting of a shell, tube sheets in which the tubes of the tube bundle are hermetically fixed, a cover, a bottom and branches for the supply and discharge of coolants, in which the upper tube sheet is made with a given outer diameter, and the upper tube sheet is connected by means of studs to a ring hermetically fixed in detachable joints fastening the upper cover to the shell, the outer diameter of which is equal to the outer diameter of the lower tube sheet [Patent for Utility Model of the Russian Federation No. 209163, IPC: F28D 7 / 16, F28F 9 / 013, published 03.02.2022].

[0005] The reasons that prevent the achievement of the specified technical result include a decrease in productivity over time due to a decrease in the rate of heat transfer during the accumulation of thermal deposits: (scale, salt stone, thermal destruction products) on the walls of the pipes and the boundary thermal layer present on both sides of the pipes, which reduces the efficiency of heat transfer.

[0006] The closest technical solution in terms of the set of features to the claimed object and adopted as a prototype is a shell-and-tube heat exchanger consisting of a shell, upper and lower tube sheets in which the tubes of the tube bundle are hermetically fixed, upper and lower covers, pipes for the supply and discharge of the first and second coolants, where the pipe for supplying the second coolant is equipped with a pulsator, each tube of the tube bundle is equipped with a cylindrical spring provided with a weight in the form of a ring and rigidly fixed on the upper tube sheet [Patent for Utility Model of the Russian Federation No. 214087, IPC B01D 3 / 28, B01D 1 / 22, published. 11.10.2022].

[0007] The reasons that prevent the achievement of the specified technical result include the fact that the pulsation effect goes to the entire volume of the coolant in the intertube space, as a result of which it is distributed unevenly and dampedly (from the coolant inlet pipe to its outlet pipe), which sets in motion only the nearby springs in a chaotic direction, as a result of which the tubes of the tube bundle begin to wear out, and the springs with the load do not have the ability to oscillate the spring and load along the length of the tube bundle, which leads to a disruption in the heat transfer process and collectively indicates a low efficiency of the heat transfer process.

[0008] The technical result of the proposed design of a shell-and-tube heat exchanger is an increase in the efficiency of the heat transfer process.

[0009] The stated technical result is achieved in a shell-and-tube heat exchanger consisting of a casing, upper and lower tube sheets in which the tubes of a tube bundle are hermetically secured, each of which is equipped with a cylindrical spring provided with a load in the form of a ring and rigidly secured to the upper tube sheet, upper and lower covers, pipes for supplying and removing the first and second coolants, a pulsator with which the pipe for supplying the second coolant is equipped, and inside the tubes of the tube bundle there are turbulators installed, made of a plate with alternating petals made of sheet material with inserts in the form of tubes equipped with limiters and rings along which the petals move, and inside the housing under the rings there is a perforated distribution grid, the diameter of the holes of which corresponds to the condition

[0010] d н <d о <d ш , (1)

[0011] where d н - outer diameter of tubes of tube bundle, m;

[0012] d о - diameter of the opening in the distribution grid, m;

[0013] d ш - diameter of the cylindrical spring load made in the form of a ring, m.

[0014] Installation of turbulators inside the tubes of a tube bundle, made of a plate with alternating petals made of sheet material with inserts in the form of tubes equipped with limiters and rings along which the petals move, allows to increase the efficiency of heat transfer by creating vortex flows of rotating elements during operation at the macro- and micro-level, to destroy the wall thermal layer on the inner surface of the tubes, and also to prevent the formation of deposits on the surface of the petal due to their continuous rotation during operation, and the inner surface of the tube walls (due to the constant interaction of vortices of the coolant flow with the surface), which together leads to an increase in the efficiency of the heat transfer process.

[0015] Placing a perforated distribution grid inside the housing under a ring, the diameter of the holes of which corresponds to condition (1), makes it possible to create a uniform pulsating effect of the coolant flow on the springs with weights in the form of rings on each tube of the tube bundle, which will lead them to harmonious axial oscillations with a large amplitude that destroy the thermal boundary layer near the outer heat-transfer surfaces of the tubes, thus intensifying the heat transfer process.

[0016] The diameter of the perforated holes in the distribution grid, according to condition (1), cannot be less than or equal to the diameter of the tube bundle, as otherwise the process will not be possible. If the diameter of the perforated holes in the distribution grid, according to condition (1), is greater than or equal to the diameter of the ring-shaped cylindrical spring weight, the coolant flow lines will not fully impact the surface of the weight, which will prevent the creation of sufficiently intense axial oscillations of the spring along the outer surface of the tube bundle.

[0017] Fig. 1 shows a diagram of the proposed design of a shell-and-tube heat exchanger.

[0018] Fig. 2 shows a tube of a tube bundle with a turbulator.

[0019] The shell-and-tube heat exchanger consists of a shell 1 with pipes for supplying a second coolant 2 and a second coolant outlet 3, moving in the intertube space. Tubes 4 of the tube bundle are installed inside the shell 1, hermetically secured in tube sheets 5 at the top and bottom. The top cover 6 and bottom cover 7 are detachably connected to the tube sheets 5 at the top and bottom, respectively. A supply pipe 8 for the first coolant is provided on the top cover 6, and a discharge pipe 9 for the first coolant is provided on the bottom cover 7.

[0020] Each tube 4 of the tube bundle is equipped with a cylindrical spring 10, rigidly fixed on the upper tube sheet 5 and provided with a load in the form of a ring 11 from below.

[0021] The supply pipe of the second coolant 2 is equipped with a pulsator 12.

[0022] Inside the housing 1, under the weights of the cylindrical springs 10, which are made in the form of rings 11, and above the lower tube sheet 5, a perforated distribution grid 13 is located, the diameter of the holes of which corresponds to condition (1). The supply pipe for the second coolant 2 is located between the lower tube sheet 5 and the perforated distribution grid 13.

[0023] Inside each tube 4 of the tube bundle, a turbulator 14 is installed, made in the form of a plate 15 with an insert in the form of a tube 16, equipped with a ring 17, on which a petal 18 is mounted with the ability to move along the ring 17. The petals 18 are made of sheet material. The tubes 16 are equipped with limiters 19, installed closer to their center.

[0024] For installation on the foundation, the shell and tube heat exchanger is equipped with 20 feet.

[0025] Example of shell and tube heat exchanger operation.

[0026] The first coolant is supplied through the supply pipe 8 into the upper cover 6, and from there into the tubes 4 of the tube bundle. This coolant begins to interact with the turbulators 14 and, getting onto the curved surface of the petals 18, will lead to the formation of a vortex flow on their back part, which will force the petals 18 to move along the rings 17 and will cause them to rotate around the tubes 16, while the limiters 19 prevent the supplied flow from pressing the rings 17 to the plates 15. This leads to intensive mixing of the coolant passing through the tubes 4 of the tube bundle at the macro- and microlevel due to the creation of vortex flows and the destruction of the wall thermal layer on the inner side of the tubes 4 of the tube bundle, and also significantly reduces the formation of deposits on the surface of the moving petals 18 and the inner surface of the tubes 4 of the tube bundle, which contributes to an increase in the efficiency of the heat transfer process.

[0027] The first coolant, passing the lower cover 7, exits through the outlet pipe 9 to the outside. The second coolant is simultaneously fed through the second coolant supply pipe 2 under the distribution grate 13 and, passing through its holes, the diameter of which corresponds to the condition (1), enters the inter-pipe space of the casing 1 and, washing the outer surface of the tubes 4, exits to the outside through the second coolant outlet pipe 3. Simultaneously with the supply of coolants, the pulsator 12 creates oscillations in the incoming flow of the second coolant, uniformly distributed throughout the entire volume of the perforated distribution grate 13, which set the cylindrical springs 10 with the ring 11 into axial movement.Under the influence of vibrations, the boundary thermal layer on the outer surface of tubes 4 is destroyed, intensifying the heat transfer process in the thermal boundary layer, which prevents the formation and accumulation of a layer of thermal deposits, while maintaining a high rate of heat transfer and facilitating the operation of the shell-and-tube heat exchanger with increased productivity.

[0028] Thus, the use of a shell-and-tube heat exchanger consisting of a shell, upper and lower tube sheets in which the tubes of the tube bundle are hermetically secured, equipped with a cylindrical spring with a load, upper and lower covers, pipes for the supply and discharge of the first and second coolants, a pulsator, turbulators made of a plate with alternating petals of sheet material with inserts in the form of tubes equipped with limiters and rings along which the petals move, and a perforated distribution grid makes it possible to increase the efficiency of the heat transfer process.

Claims

A shell and tube heat exchanger consisting of a casing, upper and lower tube sheets in which the tubes of a tube bundle are hermetically secured, each of which is equipped with a cylindrical spring provided with a weight in the form of a ring and rigidly secured to the upper tube sheet, upper and lower covers, pipes for the supply and discharge of the first and second coolants, a pulsator with which the pipe for supplying the second coolant is equipped, characterized in that turbulators are installed inside the tubes of the tube bundle, made of a plate with alternating petals made of sheet material with inserts in the form of tubes provided with limiters and rings along which the petals move, and a perforated distribution grid is located inside the housing under the weights of the cylindrical springs made in the form of rings, the diameter of the holes of which corresponds to the condition d н <d о <d ш , where d н – outer diameter of tubes of tube bundle, m; d о – diameter of the opening in the distribution grid, m; d ш – diameter of the ring-shaped load of the cylindrical spring, m.

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