WO2008131616A1

WO2008131616A1 - A short-circuit-proof heat-exchanger with helical baffles

Info

Publication number: WO2008131616A1
Application number: PCT/CN2007/003328
Authority: WO
Inventors: Xiaoping Song; Zhizhong Pei
Original assignee: Dalian Haite Oil Refining Tech; Xiaoping Song; Zhizhong Pei
Priority date: 2007-04-26
Filing date: 2007-11-26
Publication date: 2008-11-06
Also published as: CN101042289A; US20100193167A1

Abstract

A short-circuit-proof heat-exchanger with helical baffles, includes a shell (1), helical baffles (4) provided inside the shell (1) and heat-exchanging tubes (5) throughout the helical baffles (4). Each helical baffle (4) has a 360˚/4 quadrant-shaped projection. Both straight sides of the helical baffles (4) are widened and overlapped one by one. The heat-exchanging tubes (5) penetrate the widened and overlapped sections. The heat-exchanger further includes a plurality of tie rods (2), one of which is located at the central axis of the shell (1) and penetrates the widened and overlapped sections of the helical baffles (4), the othersof which penetrate the end portions of the central lines of the widened and overlapped sections' projections. The tie rods (2) are fixed on the inner surface of a tube sheet (7) on one end, and are fixed on the corresponding distal helical baffle (4) on the other end. Spacing tubes (3) are divided into several segments and are provided on the tie rods (2).

Description

Short-circuit proof spiral baffle heat exchanger

The invention relates to a shell-and-shell spiral baffle heat exchanger in the processes of petroleum, chemical, power generation, metallurgy, food, and pharmaceutical industries. Background technique

Nearly one thousand shell-and-tube spiral baffle heat exchangers have been used in China's petrochemical plants. As shown in Figure 1, the shell-and-tube spiral baffle heat exchanger is used to solve the vertical bow-baffle heat exchanger. The vertical arcuate baffle structure causes a large shell-side pressure drop, and there are problems such as a triangular dead zone occupying heat exchange area of about 2/5, serious fouling deposition, low heat exchange efficiency, and short operating cycle. The application results show that the shell-side spiral baffle structure has the advantage of reducing the shell-side fluid pressure drop compared with the vertical bow-baffle structure. However, the measured results show that the heat transfer efficiency of the shell side is not as obvious as expected. Some heat exchangers, especially large diameter heat exchangers, use a spiral baffle structure, and the heat transfer efficiency is not as good as that of the bow baffle structure.

Why is the heat transfer efficiency of the spiral baffle heat exchanger not as good as that of the bow baffle? After several simulation experiments with spiral baffle heat exchangers with different angles of different diameter shells, it was found that the short-circuit leakage reduces the ideal channel due to the large amount of medium short-circuit leakage from the triangular space formed between adjacent baffles. The flow rate, and the larger the diameter of the casing, the more significant the leakage phenomenon of the short circuit, and the more the spiral flow of the main flow channel is reduced, which reduces the flow velocity of the medium, thereby seriously weakening the heat exchange efficiency. It has been suggested to add a blocking triangle in this triangle, but this plate blocks the flow path in the same direction on the back of the baffle, increases the pressure drop, forms a new dead zone, and repeats the vertical bow baffle Overwrite.

Chinese patent "Short-proof spiral baffle shell-and-tube heat exchanger" (Patent No.: ZL200620008595.6) discloses an improved spiral baffle shell-and-tube heat exchanger, as shown in Figure 3, its characteristics For each piece of the fan-shaped baffle structure with a projection of 360° / 4, one to two rows of pipe widths are respectively added on both sides of the straight side, and the widened portions are overlapped. The simulation results show that after this improvement, the medium in the shell side passes through the shell process with an ideal spiral flow, and the short circuit phenomenon is almost no.

Even so, as can be seen from Figure 2, the tie rods on the baffle plate can not be shared, resulting in a large number of tie rods and unreasonable position and structure. The main performances are as follows: On the one hand, too many tie rods occupy the position of the heat exchange tubes, which affects The heat exchange efficiency of the entire equipment; on the other hand, each baffle is positioned on the curved side by a tie rod.

1

Confirmation However, there is no tie rod positioning near the right angle area, and the positioning effect is poor, which affects the overall rigidity and shock resistance of the heat exchange tube, thereby reducing the service life of the heat exchange tube and increasing the maintenance cost; meanwhile, due to the overlapping portion of the spiral baffle Without the same tie rod running through, the two adjacent quadrant baffles can not be connected together, which makes the assembly process of the tube bundle particularly cumbersome. Usually, the welding positioning is required before assembly, or the baffle plate is fixed on the tube bundle by wire binding. Then insert a part of the heat exchange tube, cut the weld, or remove the wire for binding. The process is cumbersome, consuming a lot of manpower and material and working hours, thereby increasing the manufacturing cost and increasing the probability of generating errors; the use of special tire positioning in foreign countries also inevitably increases the cost of manufacturing. Summary of the invention

In view of the above-mentioned deficiencies of the prior art, the present invention aims to disclose a short-circuit proof spiral baffle heat exchanger with a more reasonable structure, thereby further improving the heat exchange efficiency of the heat exchanger, and enhancing the rigidity and shock resistance of the equipment. The performance, and simplify the installation process of the tube bundle, improve the installation accuracy, reduce the manufacturing cost, and effectively improve the use efficiency and service life of the equipment.

The technical solution of the present invention is implemented as follows:

An anti-short-circuit spiral baffle heat exchanger comprises a casing, a spiral baffle inside the casing, and a heat exchange tube running through the spiral baffle, each of which is projected on both sides of a fan-shaped baffle of 360 ° /4 The straight sides are respectively widened and overlapped in sequence, and the heat exchange tube passes through the widened overlapping portion, and is characterized by further comprising a pull rod, one of the pull rods is located on the central axis of the casing and runs through the spiral baffle a wide overlapping portion, the remaining drawbars extend through the end portions of the center line of the projection of the overlapping portion of the spiral baffle; the one ends of the pull rods are respectively fixed on the inner surface of the tube sheet at one end of the housing, and the other end is fixed to the corresponding end On the last spiral baffle plate, the spacer tube is sleeved on the tie rod.

Here, the drawbar extends through the widened overlapping portion of the spiral baffle, and is distributed on two planes perpendicular to the central axis of the casing and perpendicular to each other, occupying as little as possible or occupying the position of the effective heat exchange tube, effective Increasing the heat exchange efficiency; on the other hand, the tie rod located on the central axis of the casing and the tie rods penetrating both ends of the center line of the projection of the fan-shaped spiral baffle widened to form a most effective large triangular position, thereby significantly The overall rigidity and shock resistance of the device are improved; moreover, as previously mentioned, the tie rod on the central axis runs through all the spiral baffles, and this structure has great significance for the assembly process of the tube bundle, and the structure is adopted. The assembly process of the tube bundle is greatly simplified, saving at least half of the manpower and man-hours, and eliminating the need for a dedicated mounting of the tire, which greatly saves the installation cost, and at the same time avoids the splicing and bundling. The error and the damage caused by the brutal forced pipe wear will greatly improve the accuracy and quality of the installation. The short circuit-proof spiral baffle heat exchanger further includes a connecting positioning tube and a tie rod extending through an intermediate portion of a center line of the widened overlapping portion of the spiral baffle, wherein the two ends of the connecting positioning tube A distance from the tube sheets at both ends of the housing is fixed to the baffle plate of the corresponding end portion, and one end of the pull rod is respectively fixed on the inner surface of the tube sheet at one end of the housing, and the other end is fixed to the corresponding end. On the last spiral baffle plate, the spacer tube is sleeved on the tie rod. The connecting positioning tube is a hollow metal tube, and the size thereof is the same as the outer diameter of the heat exchange tube. When the diameter of the housing is large, the connecting rod of the positioning tube is increased at the above position, especially the connection of the positioning tube is increased. On the one hand, the anti-short circuit effect is improved, on the other hand, the baffle heat exchange tube hole alignment is accurate, thereby improving the pipe penetration efficiency, and strengthening the connection between the baffles, so that the tube bundle structure is more compact, thereby improving The rigidity and seismic performance of the tube bundle further avoid radial separation during assembly.

The width of the overlapping portion of the spiral baffle is lOmn! ~ 100ram. In the case where the diameter of the casing becomes large, the width of the baffle widening and overlapping portion is also increased to sufficiently prevent the short-circuit leakage, thereby ensuring the heat exchange efficiency of the shell side.

The beneficial effects of the present invention are obvious compared to the prior art:

The technical scheme of the invention has a more reasonable and compact structure, increases the effective heat exchange area, reduces the short-circuit leakage phenomenon of the triangular dead zone, thereby improving the heat exchange efficiency; on the other hand, the rigidity of the whole device is increased. And shockproof and seismic performance, and greatly simplify the assembly process of the tube bundle, saving costs and improving work efficiency. DRAWINGS

Figure 6 of the accompanying drawings, wherein

1 is a schematic structural view of a heat exchanger of a conventional non-overlapping spiral baffle;

Figure 2 is a cross-sectional view taken along line E-E of Figure 1;

Figure 3 is a schematic view showing the structure of a heat exchanger which is improved on the basis of Figure 1;

Figure 4 is a cross-sectional view taken along line F-F of Figure 3;

Figure 5 is a schematic view of the structure of the present invention;

Figure 6 is a cross-sectional view taken along line G-G of Figure 5;

In the figure, 1, the housing 2, the tie rod 3, the distance tube 4, the baffle 5, the heat exchange tube 6, the connection positioning tube 7, the tube plate. detailed description

Example 1

The short-circuit proof spiral baffle heat exchanger has a casing 1 having a diameter of Φ 500πιπι and a casing length of 3 m, and a heat exchange tube 5 is inserted in the casing through the spiral baffle 4; the spiral baffle 4 of the casing In order to project a fan shape of 360 ° /4, the straight sides of the fan-shaped baffle 4 are respectively widened by 30 mm and overlapped in sequence, and the heat exchange tube 5 is penetrated in the widened overlapping portion; and five of the diameters are 12 mm. a tie rod 2, one of which is located on a central axis of the casing and penetrates the widened overlapping portion of the spiral baffle, and the other four tie rods extend through the center line of the projection of the overlapping portion of the spiral baffle One end of the pull rod is respectively fixed on the inner surface of the tube sheet 7 at one end of the housing, and the other end is fixed on the corresponding last spiral baffle 4, and the distance tube 3 is sleeved on the rod 2. The widened overlapping fan-shaped spiral baffles 4 guide the medium flowing through the casing 1 to eliminate the short-circuit leakage phenomenon of the triangular space formed by the straight edges of the two adjacent fan-shaped baffles; the setting of the tie rod 2 The positioning effect of the baffle 4 is greatly improved, and the position of the heat exchange tube 5 occupied by the tie rod in the existing design is effectively saved, the heat exchange area is increased, and the heat exchange efficiency is most effectively improved; and the heat transfer efficiency is located on the central axis. The pull rod 2 penetrates all the spiral baffles 4, and when the tube bundle is assembled, all the fan-shaped baffles 4 are sequentially positioned through the tie rods 2 on the central axis of the casing, and then the cage is woven, and the whole assembly process is large. For simplification, at least half of the manpower and man-hours are saved, which saves manufacturing costs; at the same time, the overall rigidity and shock resistance of the equipment are also significantly enhanced.

Example 2

For the anti-short-circuit spiral baffle heat exchanger with a large diameter of the casing 1, for example, when the diameter of the casing 1 is Φ 1200 or more, the straight sides of the fan-shaped baffles 4 are respectively widened and overlapped by more than 46 mm, that is, The width of the widened overlapping portion increases as the diameter of the casing increases, and the arrangement of the tie rod and the heat exchange tube is the same as that of the first embodiment. Unlike the first embodiment, the short-circuit proof spiral baffle is replaced. The heat exchanger further includes a hollow connecting positioning pipe 6 which is the same as the outer diameter of the heat exchange pipe 5, which is thicker than the tie rod 2, and the connecting positioning pipe 6 penetrates the center line projected by the widened overlapping portion of the spiral baffle 4. The intermediate portion is disposed between the two tie rods 2, and the two ends of the connecting positioning tube 6 are separated from the tube sheets at both ends of the housing 1 by a distance, and are fixed on the baffles of the corresponding end portions, as shown in the figure. 5 and Figure 6. The addition of the connecting positioning tube 6 further improves the anti-short circuit effect, in particular, the overall rigidity and shockproof performance of the device are enhanced, and the baffle plate and the heat exchange tube hole are aligned accurately, thereby improving the pipe penetration efficiency.

Claims

1. A short-circuit proof spiral baffle heat exchanger comprising a casing (1), a spiral baffle (4) in the casing, and a heat exchange pipe (5) penetrating the spiral baffle, each projection being The straight sides of the 360° /4 fan-shaped baffle (4) are respectively widened and overlapped in sequence, and the heat exchange tube (5) is passed through the widened overlapping portion, and is characterized in that it further comprises a pull rod (2), the pull rod One of them is located on the central axis of the casing (1) and extends through the widened overlapping portion of the spiral baffle (4), and the remaining drawing rods extend through the center line of the projection of the overlapping portion of the spiral baffle The two ends of the rod (2) are respectively fixed on the inner surface of the tube sheet at one end of the casing (1), and the other end is fixed on the corresponding last spiral baffle (4), and the distance tube ( 3) The sleeve is placed on the tie rod ( 2).

2. The short-circuit proof spiral baffle plate heat exchanger according to claim 1, further comprising a connection through an intermediate portion of a center line projected by the widened overlapping portion of the spiral baffle (4) a positioning tube (6) and a tie rod (2), wherein the two ends of the connecting positioning tube (6) are separated from the tube sheets at both ends of the housing (1) by a distance, and are fixed at the corresponding end baffles The one end of the pull rod (2) is respectively fixed on the inner surface of the tube sheet at one end of the casing (1), and the other end is fixed on the corresponding last spiral baffle (4), and the distance tube (3) The sleeve is placed on the tie rod (2).

The short-circuit proof spiral baffle heat exchanger according to claim 1 or 2, characterized in that the width of the overlapping portion of the spiral baffle (4) is lOmn! ~ 100 dishes.