RU2166716C1 - Shell-and-tube heat exchanger - Google Patents

Abstract

FIELD: applicable in heat exchangers for heating of fluid media due to the energy of vapor. SUBSTANCE: the heat exchanger has a tube bunch for liquid secured inside the shell by means of tube plates, pipe connection for inlet of operating vapor and a pipe connection for outlet of waste vapor, the pipe connection for inlet of vapor is installed in alignment inside the pipe connection for outlet of waste vapor connected to the condensate tank. EFFECT: enhanced efficiency of operation of shell-and-tube heat exchanger. 4 cl, 3 dwg

Description

 The invention relates to heat engineering, specifically to heat exchangers for heating fluids with steam energy.

 A shell-and-tube heat exchanger is known that contains headers of the inlet-outlet of the tube medium, headers of the inlet-outlet of the annulus, a heat exchange bundle in the form of Field tubes and a thin-walled shell installed in the gap (see A.S. USSR N 885784, class F 28 D 7 / 17, publ. 1981).

 The disadvantage of this type of heat exchangers is their relatively low efficiency.

 A heat exchange element is also known, containing two coaxially mounted pipes, the outer of which is plugged from the end, and the inside is permeable to the coolant along the entire length (see A.S. USSR N 1657922, class F 28 D 7/12, publ. 1991 g.). Elements of this design are not applicable in heat exchangers where direct contact between steam and heated water is unacceptable.

 Closest in design to the proposed device is a shell-and-tube heat exchanger in a. from. USSR N 1538006, class F 28 D 7/16, 1990 - prototype.

 The specified heat exchanger contains a casing with fittings for the inlet-outlet of the first heat transfer medium.

 Inside the casing there is a bundle of pipes fixed in pipe boards in communication with the manifolds for the inlet-outlet of another heat transfer medium.

 The disadvantages of the prototype include the relatively low efficiency of the heat exchanger of this design. The problem is that when using a shell-and-tube heat exchanger of the indicated design in the power system, when steam is the first medium, a significant amount of passing steam leaves the casing, having not had time to condense on pipes with another heat-transfer medium.

 Studies show that heat transfer is hindered by a film of condensate that forms on the surface of pipes. This film plays the role of a heat insulating layer and reduces the intensity of heat transfer between the first heat transfer medium and the pipe metal with another heat transfer medium.

 The technical problem is to increase the efficiency of the shell-and-tube heat exchanger.

 The technical result is achieved by the fact that in a shell-and-tube heat exchanger containing a casing, a pipe for inlet of the first heat-transfer medium, a pipe for exhaust of the spent first heat-transfer medium, a tube bundle fixed in pipe boards in communication with the collectors for the inlet-outlet of another heat-transfer medium, and according to According to the invention, the first heat transfer medium is predominantly steam, and the other heat transfer medium is predominantly liquid. In addition, the heat exchanger includes a pipe for the inlet of the first heat transfer medium, mounted coaxially inside the pipe for exhausting the spent heat transfer medium, which is located in the lower part of the casing and connected to the condensate tank.

 The heat exchanger is also characterized in that in a vertical arrangement of the tube bundle, the pipe for inlet of the first heat transfer medium is equipped with a conical tip, which is located in the annular space of the casing. The heat exchanger is also characterized in that a jet pump with a steam separator is installed on the nozzle for the inlet of the first heat transfer medium.

 The heat exchanger also differs in that in the horizontal arrangement of the tube bundle, the casing is divided into sections by internal partitions, each section is equipped with a pipe for inlet of the first heat transfer medium, which is installed coaxially inside the pipe for exhausting the spent heat transfer medium.

 The technical result consists in the fact that the steam flow introduced through the nozzle mounted along the axis of the casing is divided into many turbulent vortices that blow the pipes with TPA, not allowing drops of condensate to merge into the film. In this case, fresh steam condenses itself on dry pipes, turning into drops, which in turn are churned by a new portion of steam, etc. At the same time, the heat exchange intensity increases significantly and the fraction of passing steam decreases.

 The invention is illustrated by drawings, which show 3 options for specific performance for various operating conditions. In FIG. 1 shows the basic version of a vertical heat exchanger, figure 2 is a vertical version with a jet pump and a steam separator, figure 3 is a horizontal version of a long heat exchanger.

 The basic version of the heat exchanger contains a casing 1, inside of which pipes 2 are placed, fixed in pipe boards 3.4. Board 3 is in communication with a collector 5 having a pipe 6 for introducing cold water, and with a collector 7 having a pipe 8 for outputting heated water. Between collectors 5.7 installed waterproof partition 9.

 Board 4 is in communication with the transition chamber 10. On the board 4, a pipe 11 is fixed with a fitting 12 for outputting the spent heat-transfer medium, specifically condensate. Inside the pipe 11, a pipe 13 is coaxially fixed for introducing steam into the casing. The pipe 13 has a conical tip 13a, which is located in the annular space of the casing.

 In the second embodiment of the heat exchanger (see FIG. 2), a jet pump 14 with a steam separator 15, which is mounted on the suction part of the funnel, is fixed on the conical tip 13a.

 In the horizontal version (see Fig. 3), the heat exchanger comprises a long casing 16 with a tube bundle 17 fixed in the front 18 and rear 19 tube boards. Board 18 is in communication with a collector 20 for entering cold water and a collector 21 for outputting hot water. A waterproof partition 22 is installed between the collectors. The tube board 19 is in communication with the transition chamber 23. Inside the casing 16, partitions 24 are installed (one partition is conventionally shown), dividing its volume into sections. In each section at the bottom, a pipe 25 is welded to remove condensate from the section. The nozzles 25 are connected to a drain line 26 in communication with a condensate tank (not shown conditionally). Inside the nozzles 25, the nozzles 27 coaxially pass for introducing steam into the casing section. The nozzles 27 are connected to a steam source using the steam line 28.

 The heat exchanger shown in FIG. 1, works as follows.

 The cold water intended for heating under pressure enters through the pipe 6 to the collector 5, passes through the pipes 2 down to the transition chamber 10, from where it is forced out into the right branch of the pipe bundle 2. Here, the water rises and through the collector 7 and the pipe 8 enters the consumer distribution line.

Steam under pressure is fed through the pipe 13 into the annular space of the casing 1. The steam flow flying from the conical tip 13a reaches the tube plate 3 and, having made a 180 ^° rotation, begins to move towards the entrance. The oncoming steam flows are divided into turbulent eddies, indicated in FIG. 1, 2 arrows. These steam vortices condense on pipes 2, transferring to them the latent heat of vaporization. In this case, vortices accelerate condensate droplets that have formed on the pipes, not allowing them to merge into a continuous film. Drops flow down the pipes to the pipe 4 and through the pipe 11 and the nozzle 12 are discharged into a condensate tank.

 Some part of the downward flow of steam can, under certain conditions, enter the nozzle 11 as passing steam. Here, the passing steam in the form of a vapor-condensate mixture finally condenses, giving off the latent heat of vaporization to the pipe to remove the OTC, which reduces the efficiency of the heat exchanger. In order to return the fraction of span steam to the annular space, it is possible to use a nozzle in the form of a jet pump 14 with a steam separator 15, which is fixed directly to the tip 13a (see Fig. 2).

 The jet pump 14 operates in this way.

 The vapor-condensate mixture is sucked into the jet pump and enters the steam separator 15, which allows dry steam to pass through, but traps condensate droplets that gradually drain into the pipe 11. Dry steam is injected into the annulus to condense on pipes with another heat-transfer medium.

 For more powerful heat transfer, long heat exchangers with a bundle of long pipes are used, which are advisable to install horizontally (see Fig. 3). In the horizontal version, the cyclic movement of the steam vortices coming from the nozzles 27 in the section of the casing 16 is created by partitions 24 and the cylindrical walls of the casing. If necessary, it is possible to use jet pumps 14 similarly to option 2. The condensate formed in each section flows into the nozzles 25 and is discharged through the line 26 into a condensate tank.

 According to the scheme described above, the company Velon LLC (Yekaterinburg) manufactured the basic version of the heat exchanger and tested it, which showed good results. During the many hours of operation of the heat exchanger, the hot water at the outlet had a set temperature. At the same time, only pure condensate without span steam entered the drain pipe.

 Currently, the company is designing a horizontal heat exchanger of high capacity.

 Considering the above, it can be concluded that this device, presented in three versions that implement a single inventive concept, meets the criteria of novelty, non-obviousness and industrial applicability, in connection with which it is proposed to legal protection a patent for an invention.

Claims (4)

 1. Shell-and-tube heat exchanger comprising a casing, a nozzle for inlet of the first heat-transfer medium, a nozzle for discharging the spent first heat-transfer medium, a bundle of pipes fixed in tube boards in communication with manifolds for inlet-outlet of another heat-transfer medium, characterized in that the first heat-exchange medium it is mainly steam, and the other heat transfer medium is mainly liquid, the pipe for the inlet of the first heat transfer medium is installed coaxially inside the pipe for exhausting eploobmennoy medium, which is housed in the lower housing portion and is connected to the condensate tank.  2. The shell-and-tube heat exchanger according to claim 1, characterized in that in the vertical arrangement of the tube bundle, the pipe for inlet of the first heat-transfer medium is provided with a conical tip, which is located in the annular space of the casing.  3. Shell-and-tube heat exchanger according to claim 2, characterized in that a jet pump with a steam separator is installed on the nozzle for inlet of the first heat-transfer medium.  4. The shell-and-tube heat exchanger according to claim 1, characterized in that in the horizontal arrangement of the tube bundle, the casing is divided into sections by internal partitions, each section being equipped with a nozzle for inlet of the first heat-transfer medium installed coaxially inside the nozzle for discharging the spent heat-transfer medium.

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