JPH0244193A - Multitubular heat exchanger - Google Patents

Abstract

PURPOSE:To enable a cleaning within a pipe without any interruption of a practical use of a heat exchanger and further to enable a use of it for a long period of time by a method wherein a thermal conducting pipe cleaning mechanism is provided in which each of injection nozzles may divide and inject high pressure gas into one or a plurality of openings of the thermal conducting pipes which are present on the same radius through rotation of a high pressure gas feeding pipe. CONSTITUTION:A high pressure gas feeding pipe 10 rotatably passed through a high pressure gas supplying mechanism and capable of always supplying a high pressure gas without being influenced by its rotation caused by a driving of a motor 8 has a plurality of injection nozzles 18a, 18b, 18c and 18d opened at a different radius distance in correspondence with a distribution in a radius direction of openings of several thermal conducting pipes 2 extending in a horizontal direction and located below within an inner space of a header 4a. The high pressure gas feeding pipe 10 is vertically inserted from a central part of an upper cover 4a of multi-pipe type heat exchanger and it may be rotated in an axial direction of the multitubular heat exchanger, so that each of the injection nozzles 18a, 18b, 18c and 18d may divide and inject high pressure gas to one or a plurality of openings of the thermal conducting pipes which are present on the same radius under a rotation of the high pressure gas feeding pipe 10.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a shell-and-tube heat exchanger.

Specifically, the present invention aims to provide a shell-and-tube heat exchanger that enables continuous operation (prior art).A shell-and-tube heat exchanger is a typical type of heat exchanger. By changing the number of channels on the heat transfer tube side, the arrangement of heat transfer tubes, the arrangement of baffle plates, etc., it has the flexibility to be applied to various usage conditions without major changes to the basic structure. It is widely used in the chemical industry, petroleum refining industry, and various other industries for applications such as heaters, coolers, evaporators, condensers, or heat exchangers in a narrow sense.

However, if this multi-tube heat exchanger is used continuously for a long period of time, for example as a cooler, a layer of deposits will form on the inner walls of the heat transfer tubes, reducing heat transfer efficiency and increasing pressure loss. Therefore, it becomes necessary to clean the inside of the heat transfer tube every time a certain period of time passes.

Conventionally, cleaning the inside of the heat exchanger tubes in such a multi-tubular heat exchanger involves stopping the use of the heat exchanger, disassembling the heat exchanger by removing the lid of the heat exchanger, and cleaning the inside of the heat exchanger tubes. This was done by injecting high-pressure fluid or applying pressure to an elastic material such as rubber and passing it through a heat transfer tube. However, with these conventional methods, the use of the heat exchanger must be stopped during cleaning, which can lead to problems such as reduced operating efficiency in the plant or the need for an alternative heat exchanger. Moreover, since the heat exchanger must be disassembled, the work is complicated and requires a great deal of labor. Furthermore, from this point of view, it is difficult to frequently clean the inside of the heat exchanger pipes, and the heat exchanger must continue to be used in a state with poor heat transfer efficiency or large pressure loss, resulting in a decrease in energy efficiency in the plant. It was something that caused

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a novel multi-tubular heat exchanger. Another object of the present invention is to provide a multi-tubular heat exchanger in which the inside of the tubes can be easily cleaned. A further object of the present invention is to provide a multi-tubular heat exchanger that can be used continuously for a long period of time without reducing heat transfer efficiency or increasing pressure loss, and the inside of the pipes can be cleaned without interrupting use. It is something to do.

(Means for Solving the Problems) In a vertical multi-tube heat exchanger, the high pressure gas introduction pipe which rotatably communicates with an external high pressure gas supply mechanism is arranged such that the high pressure gas introduction pipe rotatably moves upward in a ladder manner. The high-pressure gas introduction pipe is inserted in a gas-tight manner and has a plurality of injection nozzles that open in the interior space of the upper header at different radial distances depending on the radial distribution of the openings of the plurality of heat exchanger tubes located below. Each injection nozzle is equipped with a heat exchanger tube cleaning mechanism that can separately inject high pressure gas into the openings of one or more heat exchanger tubes located on the same radius by rotation of the high pressure gas introduction tube. Achieved by a shell-and-tube heat exchanger.

(Example> Hereinafter, the present invention will be explained in more detail with reference to Examples.

FIG. 1 is a sectional view schematically showing the structure of an embodiment of the multi-tubular heat exchanger of the present invention.

As shown in FIG. 1, the multi-tubular heat exchanger of the present invention is of a vertical type, and a large number of heat exchanger tubes 2 are arranged in a vertical cylindrical body 1 at a distance from each other. It is something that exists. However, in the multi-tube heat exchanger of the present invention, the number of channels on the heat exchanger tube 2 side, the arrangement of the heat exchanger tubes 2, the arrangement of the baffle plates, etc. are arbitrary, and there is no difference in the embodiment shown in FIG. It is not limited. At both open ends of this body 1, a tube plate 3a,
3b is provided to make the inside of the shell 1 a closed space, but at the same time, these tube sheets 3a and 3b do not block the openings of the respective heat exchanger tubes 2 disposed in the shell 1, and allow the heat exchanger tubes to be 2 is kept airtight. Furthermore, heads 4a and 4b are provided on the outside of the tube sheets 3a and 3b, respectively, and the internal spaces of these heads 4a and 4b are similar to those of the tube sheets 3a and 3.
b is separated from the internal space of the shell 1, and on the other hand, the heat exchanger tube 2
It communicates with the internal space of.

Therefore, in this multi-tubular heat exchanger, the upper head 4
The first fluid flowing into the head 4a from the first fluid inlet 5a provided in the first fluid inlet 5a passes through the internal space of the communicating heat transfer tube 2, reaches the lower head 4b, and the first fluid flows into the head 4a through the first fluid inlet 5a provided in the lower head 4b. The fluid is guided out of the thread from the first fluid outlet 5b,
Heat exchanger tubes 2 are disposed, and the inner space of the heat exchanger tubes 2 is defined as the inner space of the shell 1, which is airtightly partitioned by the tube walls of the heat exchanger tubes 2 and tube sheets 3a and 3b. In order for the second fluid to flow in from the second fluid inlet 6a and to be discharged to the outside from the second fluid outlet 6b, the first fluid and the second fluid flow through the tube wall of the heat transfer tube 2. Heat exchange takes place between the two fluids.

In the multi-tubular heat exchanger of the embodiment shown in FIG. The built-in high pressure gas introduction pipe 10 is connected to the header 4a.
is inserted into the internal space of. An O-ring 11 is interposed on the fitting surface between the rotary shaft 9 and the lower high-pressure gas introduction pipe insertion, so that airtightness is maintained while being rotatable.

Further, the rotating shaft 9 is surrounded by a high-pressure gas distribution group 12 on its outer periphery outside the shell-and-tube heat exchanger. This high-pressure gas distribution base 12 has a high-pressure gas supply pipe connected to a high-pressure gas supply mechanism (not shown) at the same height as the circumferential opening 13 of the high-pressure gas introduction pipe 10 incorporated in the rotating shaft 9. A high pressure gas distribution groove 14 is inserted through the high pressure gas distribution base 12 and is open on the inner circumference, and a high pressure gas distribution groove 16 is provided on the inner circumference of the high pressure gas distribution base 12 over the entire circumference including the opening 15 of the high pressure gas supply pipe 14. There is. Therefore, as the rotating shaft 9 rotates, the position of the circumferential opening 13 of the high-pressure gas introduction pipe 10 moves on the rotating surface, and the opening 1 of the high-pressure gas supply pipe 14 moves on the rotating surface.
5, the high-pressure gas distribution groove 16 communicating with the opening 15 always faces the high-pressure gas distribution groove 16, and as a result, the high-pressure gas introduction pipe 10 is always free of gas regardless of its rotation. High pressure gas will be supplied.

Furthermore, on the fitting surface between the rotating shaft 9 and the high pressure gas distribution base 12,
O-rings 17 are interposed above and below this high-pressure gas distribution groove 15, and as mentioned above, the airtightness at the communication portion between the high-pressure gas introduction pipe 10 and the high-pressure gas supply pipe 14 or the high-pressure gas distribution groove 16 is maintained. It is maintained. However, in the multi-tubular heat exchanger of the present invention, the communication method between the high pressure gas supply mechanism and the high pressure gas introduction pipe is as shown in FIG. For example, the airtightness in the rotating communication part is not limited to the example shown in the example.
It can also be held by various known methods, such as a method of mechanically sealing by forming a contact surface perpendicular to the axis of rotation.

In this way, the high-pressure gas introduction pipe 10 is connected to the high-pressure gas supply mechanism in a rotatable manner and is capable of constantly supplying high-pressure gas without being affected by the rotation driven by the motor 8.
In the internal space of a, a plurality of injection nozzles 18a, 18b, 18c, and 18d extend horizontally and open at different radial distances depending on the distribution in the radial direction of the openings of a large number of heat exchanger tubes 2 located below. are doing. As described above, the high-pressure gas introduction pipe 10 is inserted vertically from the center of the upper cover 4a of the shell-and-tube heat exchanger, and since it can rotate in the axial direction of the shell-and-tube heat exchanger, each injection nozzle 1
8a, 18b, 18c, 18d are high pressure gas introduction pipes 10
The rotation allows high-pressure gas to be separately injected into the openings of one or more heat exchanger tubes located on the same radius. That is, with such a small number of injection nozzles, it is possible to inject high-pressure gas to all the heat exchanger tubes 2 in the multi-tube heat exchanger.

In the multi-tubular heat exchanger of the present invention, only one high-pressure gas introduction pipe may be installed in the upper header, but as in the embodiment shown in FIG. Providing an injection nozzle is preferable in terms of operability and efficiency when cleaning the inside of the heat exchanger tube.

In the embodiment shown in FIG. 1, the lower header 4b
A deposit removal port 19 is provided at the center of the bottom of the heat exchanger tube 2, and by operating the heat exchanger tube cleaning mechanism as described above, deposits that are removed from the inner surface of the heat exchanger tube 2 and deposited on the lower header 4b are removed. It is possible to take it out.

The shell-and-tube heat exchanger of the present invention having such a configuration is suitably used as a cooler in various industries. Cooling of gases containing sublimable organic compounds such as naphthalic anhydride, pyromellitic anhydride, anthraquinone, etc. It is particularly effective when used in That is, a gas containing such a sublimable organic compound is passed through the heat exchanger tubes of a multi-tubular heat exchanger, and a cooling medium is passed outside the heat exchanger tubes, thereby indirectly cooling the gas through the walls of the heat exchanger tubes. In this case, a large amount of crystals of the sublimable organic compound precipitated by cooling adheres to the inner wall of the heat exchanger tube, so it is important to clean the inside of the heat exchanger tube by the heat exchanger tube cleaning mechanism as described above. In addition, if there is a large temperature difference between the gas containing the sublimable organic compound and the cooling medium, for example 30°C
When the temperature difference exceeds the temperature difference, the crystals of the sublimable organic compound precipitated by cooling stick to the inner wall of the heat exchanger tube, so cleaning the inside of the heat exchanger tube tends to be more difficult than when the temperature difference is small.

In addition, as the high-pressure gas used to remove the deposits adhering to the inner wall of the heat exchanger tube, it is preferable that the gas is inert to the fluid such as the gas to be cooled flowing inside the heat exchanger tube. Furthermore, when using the fluid after cooling, it is preferable to use a fluid that does not hinder its usage. For example, for gases containing sublimable organic compounds such as those mentioned above, combustion exhaust gas, nitrogen gas, etc. can be used.

Furthermore, when using the shell-and-tube heat exchanger of the present invention, even if the injection of high-pressure gas into the heat exchanger tubes by the heat exchanger tube cleaning mechanism is performed continuously throughout the operation of the shell-and-tube heat exchanger, Alternatively, it may be controlled intermittently by a pulse mechanism, etc., but in any case, the internal heat transfer tubes can be cleaned without interrupting the operation of the multi-tube heat exchanger. It is something.

(Effects of the Invention) As described above, in the shell-and-tube heat exchanger of the present invention, the high-pressure gas introduction pipe, which rotatably communicates with the external high-pressure gas supply mechanism, is arranged so that the high-pressure gas introduction pipe is rotatably and airtightly connected to the upper part. The high-pressure gas introduction pipe is inserted into the inner space of the upper header and has a plurality of injection nozzles that open at different radial distances depending on the radial distribution of the openings of the plurality of heat transfer tubes located below. It is characterized in that each injection nozzle is equipped with a heat exchanger tube cleaning mechanism that can separately inject high pressure gas into the openings of one or more heat exchanger tubes existing on the same radius by rotation of the high pressure gas introduction tube. Therefore, since the heat exchanger tubes inside a shell-and-tube heat exchanger can be cleaned very easily without stopping the operation of the shell-and-tube heat exchanger, shell-and-tube heat exchangers are used. It is possible to improve the operating efficiency and energy efficiency of the plant.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing the structure of an embodiment of the multi-tubular heat exchanger of the present invention. 1... Shell, 2... Heat exchanger tube, 3a, 3b... Tube plate,
4a, 4b...Header 7...High pressure gas introduction pipe insertion port, 8...Motor 9.
... Rotating shaft, 10... High pressure gas introduction pipe, 11.17.
...0 ring, 12...high pressure gas distribution tower, 14...
High pressure gas supply pipe, 16... High pressure gas distribution groove, 18a,
18b, 18s, 18d=--Injection nozzle, 19...
Debris removal port.

Claims (1)

[Claims] (1) In a vertical multi-tubular heat exchanger, a high pressure gas introduction pipe that rotatably communicates with an external high pressure gas supply mechanism is rotatably and airtightly inserted into the upper header, and this high pressure gas introduction pipe is The internal space of the upper header has a plurality of injection nozzles that open at different radial distances according to the distribution in the radial direction of the openings of a large number of heat transfer tubes located below, and each injection nozzle is connected to a high-pressure gas introduction pipe. 1. A multi-tube heat exchanger comprising a heat exchanger tube cleaning mechanism capable of separately injecting high-pressure gas into the openings of one or more heat exchanger tubes located on the same radius by rotation of the tube.