RU187107U1 - RETAILER WITH STEAM SPACE - Google Patents

Abstract

The utility model relates to the field of power engineering, namely, to the design of shell-and-tube heat exchangers with a steam space, designed for boiling and vaporizing liquid products in the chemical, petrochemical, and other industries.

The steam reboiler consists of a distribution chamber (1), a casing (2), a drain chamber (3), a tube bundle (4) with a floating head (5). The distribution chamber (1) can be made with a removable or blank cover. The floating head (5) is moved outside the casing (2) and is closed by a separate cover (6). A drain chamber (3) with an overflow partition (7) is placed on the side surface of the casing. Between the supporting surfaces (9) of the casing (2) and the sliding strips (10) of the tube bundle (4), a guide channel (8) is organized. The reboiler is equipped with level gauge pipes (12), which monitor the liquid level, and a drain pipe (11). Above the steam space (13) is a device for the separation of steam (14).

The technical results achieved in the implementation of the utility model are: an increase in the heat-exchange surface area with a constant diameter of the tube bundle and distribution chamber, a decrease in the dimensions of the apparatus, in particular in length, an improvement in the service conditions of the floating head without removing it from the apparatus together with the entire tube bundle. 7 c.p. f-ly, 2 ill.

Description

The utility model relates to the field of power engineering, namely, to the design of shell-and-tube heat exchangers with a steam space, designed for boiling and vaporizing liquid products in the chemical, petrochemical, and other industries.

In order to deepen the processing of raw materials in various technological processes, liquid products are boiled and evaporated, for which horizontal heat exchangers with a steam space are used - the so-called. reboilers (boilers or evaporators). Typically, such devices consist of a casing and a tube bundle immersed in a liquid. A coolant is supplied to the tube bundle, due to the heat of which heating and boiling of the liquid product takes place. The separation of the generated vapor occurs in the vapor space, which is located above the boiling liquid and is created by constantly maintaining its normal level in the casing.

Due to the large temperature difference between the heat transfer medium and the refrigerant (liquid product in the casing) and the need to compensate for the corresponding difference in the temperature elongations of the casing and heat transfer pipes, two types of tube bundles are used in the heat exchangers - with U-shaped heat transfer pipes and with floating heads - which are placed in blind casings . The fundamental difference between them is that the floating head allows you to clean the inner surface of the direct heat transfer pipes, and U-shaped heat transfer pipes do not have this possibility. Therefore, in devices with floating heads, less pure heat carriers can be used, which are prone to the formation of deposits on the heat exchange surface. However, the practical realization of this advantage of tube bundles with floating heads in known designs is difficult, since removing the cover of the floating head requires complete disassembly of the entire apparatus to remove the tube bundle together with the cover from the deaf casing. The tightness control of the floating head and its maintenance are also impossible without removing the entire tube bundle together with the cover from the casing of the apparatus. In addition, in known devices, the removal of the liquid residue of the vaporized product is carried out through a drain chamber located at the end of the casing behind the tube bundle and the drain wall. This requires, on the one hand, a significant increase in the length of the casing and the apparatus as a whole, and on the other hand, leads to a certain unevenness in the concentration of the evaporated product along the length of the tube bundle, which ultimately affects the intensity of the processes of heating, boiling, and evaporation of the liquid product.

From the prior art, in practice, reboilers of the ACT, VKT and SKT types are widely known (in accordance with the classification according to the international standard TEMA), that is:

- with distribution chambers of types A, B and C (type A - channel type with a removable cover, type B - channel type with a blind cover, type C - channel type with a welded tube sheet and a removable cover);

- with a casing of type K, that is, a type of boiler with a steam space;

- with a full bore floating head of type T, which is placed in the casing and removed from it only assembled with a tube bundle, being the only possible option for use in a deaf casing.

A common drawback of all of the above devices is the use of a T-type floating head in them, the cover of which must be mounted on a movable tube sheet before assembling a tube bundle with a casing due to its placement in a non-separable blind housing. At the same time, the mass of the tube bundle assembled with the casing increases significantly, the leakage of the floating head requires its removal from the casing together with the tube bundle, the use of a full bore floating head significantly reduces the heat exchange surface area with comparable tube bundle sizes.

Known heat exchanger containing a casing, a tubular lattice of a floating head, heat transfer tubes, a fixed tube lattice, a distribution chamber with a lid, while the heat exchanger further comprises a hatch for mounting a tube bundle, a pipe for leaving the remainder of the product, a drain pipe, a pipe for entering the liquid product, a nozzle for the exit of gas or liquid (thermal agent), a nozzle for the entrance of gas or liquid (thermal agent) and a hatch for inspection (RF Patent for the invention No. 2306514, IPC F28 D7 / 00. publ. September 20, 2007).

A disadvantage of the known device is the use of a floating head in it, the cover of which must be mounted on a movable tube sheet before assembling the tube bundle with a casing due to its placement in a non-separable blind housing. Installation and maintenance of the floating head is limited by the dimensions of the hatches and the dimensions of the casing. In this case, the mass of the tube bundle assembled with the casing increases significantly, and the leakage of the floating head requires its removal from the casing together with the tube bundle. The use of a full bore floating head significantly reduces the heat-exchange surface area with comparable tube bundle sizes.

The task to which the present utility model is directed is to create a reboiler design with a steam space, which allows to increase the efficiency of the apparatus while reducing the cost of its manufacture and maintenance.

The technical results achieved in the implementation of the utility model are an increase in the area of the heat exchange surface with a constant diameter of the tube bundle and distribution chamber, a decrease in the dimensions of the apparatus, and improvement of the service conditions of the floating head without removing it from the apparatus along with the entire tube bundle.

To achieve the claimed technical result in a reboiler with a steam space containing a channel-type distribution chamber, a casing and a tube bundle with a floating head, according to a utility model, the floating head is moved outside the casing and closed with a separate cover.

In this case, the following can be used in the reboiler:

- channel type distribution chamber with a removable cover;

- channel type distribution chamber with blank cover;

- channel type distribution chamber with welded tube sheet and removable cover;

- floating head, sealed outside;

- a floating head with a movable tube sheet sealed from the outside;

- one drain chamber placed on the side surface of the casing;

- two drain chambers placed on opposite side surfaces of the casing;

- a device for the separation of steam in the vapor space of the casing;

- a channel for uniform distribution of the liquid product stream along the entire length of the tube bundle.

The utility model is illustrated by drawings.

Figure 1 shows a longitudinal section of a reboiler with steam space. Figure 2 presents a cross section of a reboiler with steam space.

The reboiler consists of a distribution chamber 1, a casing 2, a drain chamber 3, a tube bundle 4 with a floating head 5. In the reboiler, the floating head 5 is moved outside the casing and is closed by a separate cover 6. On the side surface of the casing there is a drain chamber 3 with an overflow partition 7, maintaining a normal fluid level. A distribution channel 8 is formed between the supporting surfaces 9 of the casing 2 and the sliding strips 10 of the tube bundle 4. The reboiler is equipped with nozzles for level gauges 12 that control the liquid level and a drain nozzle 11. Above the steam space 13 is a device for separating steam 14.

Placing the floating head 5 outside the casing 2 allows its assembly after placing the tube bundle 4 in the casing 2 and perform maintenance without removing the tube bundle 4 from the reboiler. In case of leakage of the floating head 5 during operation, it is enough to disassemble the cover 6 of the casing 2 for repair work.

Due to the removal of the floating head 5 outside the casing 2, the outer diameter of its cover is not limited to the inner diameter of the distribution chamber 1, which can significantly increase the number of heat transfer pipes placed in the movable tube sheet. With a constant size of the distribution chamber, the heat-exchange surface area in such an apparatus increases by no less than 40% in comparison with the known structures. So, for example, in the well-known reboiler with a diameter of Ø1200 mm with a T type floating head with a heat exchange pipe length of 6 m, the heat exchange surface area is 357 m ² , and in a floating head apparatus outside the casing, the heat exchange surface area will be at least 499 m²

In addition, the removal of the floating head 5 outside the casing 2 involves placing the drain chamber 3 along the lateral cylindrical part of the casing, which leads to a significant reduction in the total length of the reboiler. Moreover, the length of the overflow partition 7 is at least half the length of the tube bundle 4, which greatly facilitates the removal of the liquid residue of the boiling product.

In contrast to the known construction, the tube bundle 4 in the reboiler is raised above the lower generatrix of the casing 2. The guide channel 8, located under the tube bundle 4 and formed by the supporting surfaces 9 of the casing 2 and the slip bands 10 of the tube bundle 4, ensures uniform distribution of the liquid product flow, entering the reboiler, along the entire length of the heat exchange tubes and directs it into the tube bundle 4, which, of course, contributes to the intensification of heat transfer, as it eliminates bypass (parasitic) flows.

The drain chamber 3, located on the side surface of the casing, is made in the form of a pocket equipped with a drain pipe 11, through which the liquid residue of the boiling product is removed from the apparatus. If necessary, the reboiler can be equipped with a second drain chamber located on the opposite side of the casing 2.

Equipping the heat exchanger with nozzles 12 for level gauges allows you to control the liquid level, both in the drain chamber and in the device itself, in order to prevent overheating of the heat exchanger tubes during drainage and to prevent the passage of steam through the drain chamber.

To exclude the entrainment of droplets of boiling liquid with a steam stream from the vapor space 13, the reboiler can be equipped with a device for separating steam 14.

Thus, in comparison with the known technical solution, the proposed reboiler design has the following advantages:

- increased heat exchange surface area, which is not less than 40% higher than a similar characteristic of a standard reboiler having a comparable diameter of the distribution chamber;

- high intensity of heat transfer, which is ensured by optimizing the high-speed mode of flow of the coolant and a corresponding increase in the degree of heating of the heat exchange tubes;

- increased reliability and durability, which are a consequence of the removal of the floating head outside the casing and ensuring its high strength and accessibility for maintenance during operation;

- simplicity of manufacture and operation, which is ensured by the removal of the floating head outside the casing and the creation of conditions for its convenient collection, both during the assembly of the tube bundle itself and the apparatus as a whole.

The claimed technical solution meets the criterion of "novelty", because the prior art did not identify technical solutions with the proposed set of features, and the criterion of "industrial applicability".

Claims (8)

1. Reboiler with a steam space, comprising a channel-type distribution chamber with a removable or blind cover, a casing and a tube bundle with a floating head, characterized in that the floating head is moved outside the casing and closed with a separate cover. 2. The reboiler according to claim 1, characterized in that the channel-type distribution chamber is made with a welded tube sheet and a removable cover. 3. The reboiler according to claim 1, characterized in that the floating head is sealed on the outside. 4. The reboiler according to claim 1, characterized in that the floating head is made with a movable tube sheet sealed from the outside. 5. The reboiler according to claim 1, characterized in that it contains one drain chamber located on the side surface of the casing. 6. The reboiler according to claim 1, characterized in that it contains two drain chambers located on opposite sides of the casing. 7. Reboiler according to claim 1, characterized in that the steam space of the casing contains a device for separating steam. 8. The reboiler according to claim 1, characterized in that it contains a distribution channel of the liquid product.

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