CN104406430A - Winding tubular heat exchanger provided with vertical partition plate in cavity - Google Patents

Abstract

The invention discloses a winding tube heat exchanger in which a vertical partition is arranged in a cavity. It includes a shell and a central tube; the central tube is set in the cavity of the shell to form a ring cavity; a number of winding pipes are wound in the ring cavity; a number of metal orifice plates are arranged in the ring cavity ; The metal orifice plate is vertically arranged in the ring cavity, and the winding tube passes through the through hole on the metal orifice plate; one end of the metal orifice plate is connected to the inner wall of the housing, and the other end Connected to the outer wall of the central cylinder; a gas-liquid distributor is provided in the cavity between the metal orifice plate and the top of the housing. The present invention divides a complete cavity into several independent cavities by vertically arranging metal orifice plates inside the cavity, and the refrigerant inside each independent cavity will not flow into other cavities, so it can ensure that it enters the cavity. The liquid film of the refrigerant on the shell side of the independent cavity fully exchanges heat with the working fluid in the tube inside the cavity, and will not flow into other independent cavities due to the inclination of the hull, resulting in the failure of the heat exchange inside the original cavity.

Description

Winding tube heat exchanger with vertical partitions in the cavity

technical field

The invention relates to a coiled tube heat exchanger with vertical partitions arranged in a cavity, and belongs to the technical field of low temperature heat exchange.

Background technique

Spiral tube heat exchangers are the primary cryogenic heat exchangers of choice for large offshore natural gas floating platforms. According to statistics, 90% of large-scale offshore natural gas floating platforms use coiled tube heat exchangers. The wound tube heat exchanger is formed by winding multiple layers of circular tubes around the central tube. Each layer of coiled tubes is separated by a metal spacer. in the cavity between the outer housings. The hot medium in the tube exchanges heat with the cold medium flowing in the cavity. Such coiled tube heat exchangers are described in the following public documents: Hausen/Linde, Cryogenic Technology, 2nd Edition, 1985, pp. 471-475; Gu Anzhong, Liquefied Natural Gas Technical Handbook, 1st Edition, 2012 , pp. 484-485. In the above-mentioned published documents, the shell side of the wound tube heat exchanger is a complete cavity, and the refrigerant on the shell side can freely circulate. When the wound tube heat exchanger is applied to an offshore floating platform, the inclination angle of the sea sloshing will cause the two-phase refrigerant distribution on the shell side to be uneven. area, the outer wall of the other side of the winding tube is not covered by liquid film, which is the evaporation area. The uneven distribution of the liquid film on the shell side caused by the tilting of the hull during sea sloshing is not obvious at the top of the cavity, but very obvious at the middle and bottom of the cavity. Studies have shown that the uneven distribution of the liquid film on the shell side will cause the performance of the heat exchanger to drop by 30%, and in severe cases, the entire heat exchanger will fail.

After searching the literature of the prior art, it was found that an improved design for the uneven distribution of the liquid film on the shell side of the existing wound tube heat exchanger has appeared. For example, the Chinese patent application number is 200580028572. A coiled tube heat exchanger with a distributor for distributing the liquid on the shell side as described in "Heater". The wound heat exchanger described in this invention has a distributor for distributing the liquid in the external space, which is beneficial to reduce the uneven distribution of gas and liquid at the top inlet of the shell side cavity, but it cannot solve the problem of the shell side under the sea sloshing condition. The problem of uneven gas-liquid distribution in the middle and bottom of the cavity.

Contents of the invention

The object of the present invention is to provide a wound tube heat exchanger with a vertical partition in the cavity. The present invention replaces the conventional wound tube heat exchanger with a vertical metal orifice inside the shell side cavity. The traditional metal gasket divides the entire cavity into several independent cavities, and the refrigerant between the independent cavities cannot circulate freely, but can only flow downward inside the independent cavity, avoiding the shell caused by sea sloshing. The poor heat transfer conditions of partial evaporation and partial accumulation of liquid inside the body.

The wound tube heat exchanger provided by the present invention has a vertical partition in the cavity, which includes a shell and a central cylinder; the central cylinder is arranged in the cavity of the shell to form a ring cavity; the ring There are several winding tubes wound in the cavity;

Several metal orifice plates are arranged in the ring cavity; the metal orifice plates are vertically arranged in the ring cavity, and the winding pipe passes through the through holes on the metal orifice plates; One end is connected to the inner wall of the housing, and the other end is connected to the outer wall of the central cylinder;

A gas-liquid distributor is arranged in the cavity between the metal orifice plate and the top of the housing.

In the coiled tube heat exchanger, the metal orifice plates are arranged symmetrically along the circumference of the central cylinder.

In the coiled tube heat exchanger, the metal orifice plate has a thickness of 1 mm to 3 mm, and the size of the through holes provided on it is determined by the outer diameter of the coiled tube: the orifices on the orifice plate form a linear array Arrangement, the transverse spacing of the orifices is equal to the radial spacing between the winding tubes of each layer, and the longitudinal spacing of the orifices is equal to the axial spacing between the adjacent winding tubes of the same layer, so that the winding tubes can just pass through each layer through holes for fixing.

In the coiled tube heat exchanger, the outer diameter of the coiled tube is 5 mm to 30 mm.

In the coiled tube heat exchanger, the metal orifice plate is welded to the shell and the central cylinder, which improves the strength.

When using the wound tube heat exchanger of the present invention, the shell-side refrigerant flows from the upper part of the shell through the gas-liquid distributor into each independent cavity separated by the metal orifice plate arranged vertically, from top to bottom The falling film flows down the outer wall of the coiled tube, and finally flows out from the bottom of the heat exchanger; after entering the heat exchanger, the fluid in the tube flows from bottom to top along the inner wall of each coiled tube, and passes through the wall of the coiled tube and the shell. The refrigerant on the side exchanges heat, and finally flows out from the top of the heat exchanger, realizing the heat exchange between the fluid and the refrigerant.

Compared with the existing coiled tube heat exchanger, the present invention divides a complete cavity into several independent cavities by vertically setting metal orifice plates inside the cavity, and the refrigerant inside each independent cavity It will not flow into other cavities, so it can ensure that the liquid film of the shell-side refrigerant entering the independent cavity can fully exchange heat with the working medium in the tube inside the cavity, and will not flow into other independent cavities due to the inclination of the hull. The heat exchange inside the original cavity fails. By installing metal partitions under sea sloshing conditions, the coverage of the liquid film area is increased by at least 20%, which means that the effective heat transfer area of the heat exchanger is increased by 20%, and the overall heat transfer performance is also increased by more than 20%. In addition, all the winding pipes in the present invention need to be fixed through the metal orifice plate, and the metal orifice plate is welded together with the central cylinder and the shell, which can withstand high strength stress and is suitable for sea sloshing conditions.

Description of drawings

Fig. 1 is a schematic structural view of a wound tube heat exchanger with vertical partitions installed in the cavity of the present invention.

Fig. 2 is a comparison diagram of the application effect of the wound tube heat exchanger (right picture) with vertical partitions in the chamber of the present invention and the existing wound tube heat exchanger (left picture) under sea sloshing conditions.

The marks in the figure are as follows:

1 winding pipe, 2 metal orifice plate, 3 central cylinder, 4 shell, 5 gas-liquid distributor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

As shown in Figure 1, the coiled tube heat exchanger with vertical partitions arranged in the cavity of the present invention includes a shell 1 and a central cylinder 3, wherein the central cylinder 3 is arranged in the cavity of the shell 1, forming a a ring cavity. A plurality of winding tubes 1 are wound in the annular cavity for passing in fluid. There are a plurality of metal orifice plates 2 in the ring cavity, which are vertically arranged in the ring cavity and arranged symmetrically along the circumference of the central cylinder 3, and each layer of winding pipe 1 passes through the through holes on each metal orifice plate 2 to fix. One end of the metal orifice plate 2 is welded on the inner wall of the housing 4, and the other end is welded on the outer wall of the central cylinder 3, which enhances its strength. A gas-liquid distributor 5 is provided in the cavity between the metal orifice plate 2 and the top of the housing 4 for distributing refrigerant.

In the above coiled tube heat exchanger, the outer diameter of the coiled tube 1 can be adjusted in the range of 5 mm to 30 mm.

In the above-mentioned wound tube heat exchanger, the thickness of the metal orifice plate 2 can be adjusted within the range of 1 mm to 3 mm, and the size of the through hole set on it is determined by the outer diameter of the coiled tube 1: the orifice on the orifice plate is Arranged in a linear array, the horizontal spacing of the orifices is equal to the radial spacing between the winding tubes of each layer, and the longitudinal spacing of the orifices is equal to the axial spacing between adjacent winding tubes of the same layer, so that the winding tube 1 can just pass through Each through hole is fixed.

When applying the wound tube heat exchanger of the present invention, the shell-side refrigerant flows from the upper part of the shell 4 through the gas-liquid distributor 5 into each independent cavity separated by the vertical metal orifice plate 2, and flows along the winding tube from top to bottom. The falling film on the outer wall of the tube 1 flows down, and finally flows out from the bottom of the heat exchanger; the fluid in the tube enters the heat exchanger and flows along the inner wall of each coiled tube 1 from bottom to top, passing through the refrigerant on the wall of the coiled tube 1 and the shell side The heat exchange is carried out, and finally flows out from the top of the heat exchanger, realizing the heat exchange of the fluid.

The schematic diagram of the application effect comparison between the coiled tube heat exchanger with vertical partitions in the chamber of the present invention and the existing coiled tube heat exchanger is shown in Figure 2, and the left figure in Figure 2 is the existing coiled tube heat exchanger The schematic diagram of the application effect of the heat exchanger. The right diagram in Figure 2 is a schematic diagram of the application effect of the coiled tube heat exchanger of the present invention. Comparing these two diagrams, it can be seen that the present invention integrates the complete metal orifice plate 2 vertically inside the cavity. A cavity is divided into several independent cavities, and the refrigerant inside each independent cavity will not flow into other cavities, so it can ensure that the liquid film of the shell-side refrigerant entering the independent cavity is consistent with the inside of the cavity. The working medium in the tube is fully heat-exchanged, and will not flow into other independent cavities due to the inclination of the hull, which will cause the heat exchange failure inside the original cavity.

According to the actual test, by installing the metal orifice plate 2 under the sea sloshing condition, the coverage of the liquid film area is increased by at least 20%, which means that the effective heat exchange area of the heat exchanger is increased by 20%, and the overall heat exchange performance is therefore Improve by more than 20%.

In addition, all coiled pipes 1 in the present invention need to be fixed through the through holes on the metal orifice plate 2, and the metal orifice plate 2 is welded together with the central cylinder 3 and the shell 4, which can withstand high strength stress. Suitable for sea sloshing conditions.

Claims (5)

1. a wrap-round tubular heat exchanger for vertical clapboard is set in cavity, it is characterized in that: it comprises housing and central tube; Described central tube is arranged in the cavity of described housing, is formed with ring cavity; Be wound with some around pipe in described ring cavity;

Several metal perforated plates are provided with in described ring cavity; Described metal perforated plate is vertically arranged in described ring cavity, described around pipe through the through hole on described metal perforated plate; One end of described metal perforated plate is connected to the inwall of described housing, and the other end is connected to the outer wall of described central tube;

A gas-liquid uniform distributer is provided with in cavity between the top of described metal perforated plate and described housing.

2. wrap-round tubular heat exchanger according to claim 1, is characterized in that: described metal perforated plate is arranged symmetrically with along the circumference of described central tube.

3. wrap-round tubular heat exchanger according to claim 1 and 2, is characterized in that: the thickness of described metal perforated plate is 1mm ~ 3mm.

4. the wrap-round tubular heat exchanger according to any one of claim 1-3, is characterized in that: the described external diameter around pipe is 5mm ~ 30mm.

5. the wrap-round tubular heat exchanger according to any one of claim 1-4, is characterized in that: described metal perforated plate and described housing and described central tube are and are welded and fixed.