A small-hole segmental baffle heat exchanger

Abstract

The application discloses a small-hole segmental baffle tube-shell heat exchanger, and belongs to the heat exchanger field. The heat exchanger can be a fixed tube plate type, a floating head type and a U-shaped tube type heat exchanger. Two rows of small holes are formed in the corresponding baffle between the tube holes, but the number of the small holes is not limited to two, and the position of the small holes can be close to or far from the notch. The shell side fluid of the common segmental baffle heat exchanger is changed from the transverse flow through the tube bundle into a mixed flow which is a combination of the transverse flow perpendicular to the tube bundle and the longitudinal flow parallel to the tube bundle. The tube holes of the heat exchange tube are distributed according to the conventional technology, and can be arranged in a triangular or square mode. The application obviously reduces the flow "dead zone", lowers the shell side pressure drop and slows down the vibration and abrasion of the tube bundle.

Description

Technical Field

[0001] The invention belongs to the technical field of heat exchangers, and specifically relates to a bow-shaped baffle heat exchanger with small holes. Since the small holes are processed on the bow-shaped baffles, the shell-side fluid in the traditional bow-shaped baffle heat exchanger is transformed from a transverse flow perpendicular to the tube bundle to a mixed flow - with both longitudinal flow parallel to the tube bundle and transverse flow perpendicular to the tube bundle. Background Art

[0002] Shell-and-tube heat exchangers, with their simple structure, low cost, and strong adaptability, are widely used in fields such as petrochemicals, metallurgy, light industry, and energy. They hold approximately 70% of the market share in heat exchange equipment, maintaining an irreplaceable dominant position. They typically consist of a tube box, tube sheet, shell, baffles, heat exchange tubes, tie rods, spacer tubes, and nozzles. Traditional bowed baffles not only support the tube bundle within the shell of a horizontal heat exchanger but also guide fluid flow through specific channels, increasing flow velocity, turbulence, and heat transfer characteristics. However, due to the transverse flow of the shell-side fluid, bowed baffles have several drawbacks, including the formation of a large "dead zone" behind the baffle, severe and harmful vibration caused by transverse flow, and significant pressure loss, scaling, and leakage at the baffle notches. In order to change this undesirable flow state of shell-side fluid, scholars from various countries have developed a variety of new tube bundle support structures and put them into use, such as deflector rods, spiral deflectors, longitudinal flow deflectors (three-leaf orifice plates, rectangular orifice plates, plum blossom orifice plates and mesh orifice plates, etc.). Summary of the Invention

[0003] The present invention aims to solve the technical problems existing in traditional bow-shaped baffle heat exchangers and provides a bow-shaped baffle heat exchanger with small holes. The shell-side fluid has both transverse flow perpendicular to the tube bundle and longitudinal flow along the tube bundle, which can effectively improve the flow "dead zone" behind the baffle, improve the heat transfer efficiency, and reduce the vibration and wear of the tube bundle.

[0004] The present invention provides a shell-and-tube heat exchanger with arched baffles and small holes, including fixed tube-sheet heat exchangers, floating head heat exchangers, and U-tube heat exchangers. The baffles are characterized by small circular holes distributed between the tube hole arrays, arranged in two or three rows, etc. Furthermore, each row of small circular holes is evenly distributed between two adjacent rows of tube hole arrays, and the small circular holes can be positioned close to or away from the notches. The diameter of the small circular holes varies depending on the diameter of the heat exchange tubes and is 5-15 mm smaller than the diameter of the heat exchange tubes. Furthermore, two rows of small circular holes are distributed between three adjacent rows of tube hole arrays.

[0005] The present invention has a small hole bow baffle shell and tube fixed tube plate heat exchanger. Figure 1, comprising a first cylinder (3), a first shell-side fluid inlet (7) and a first shell-side fluid outlet (12) are respectively opened at both ends of the first cylinder (3), a first fixed tube sheet (2) is provided at both ends of the first cylinder (3), the outer sides of the two tube sheets are respectively connected to two first tube boxes (1), the two first tube boxes (1) are respectively opened with a first tube-side fluid inlet (8) and a first tube-side fluid outlet (12), a first heat exchange tube bundle (6) and a first bow-shaped baffle (4) are arranged in the first cylinder (3), the baffle is perpendicular to the tube bundle and is fixed axially and parallelly by a first tie rod (10) and a first distance tube (5), the first tie rod (10) is fixed on the first fixed tube sheet (2), and the first bow-shaped baffle (4) is provided with a small circular hole. When the shell-and-tube fixed tube sheet heat exchanger with the bow-shaped baffles and small circular holes of the present invention is in operation, after the shell-side fluid enters the shell, a portion of the fluid flows in a "Z" shape under the guidance of the bow-shaped baffles, and the other portion of the fluid passes through the small circular holes on the baffles and passes through other baffles in the same manner to exchange heat with the tube-side fluid.

[0006] In actual application, the first cylinder (3) is generally placed on the first saddle (9). The heat exchange tube holes on the first bow-shaped baffle (4) with small holes are arranged according to conventional technology, wherein the diameter of the heat exchange tube holes is designed according to the heat exchanger standard GB151, and the diameter of the small circular hole varies according to the diameter of the heat exchange tube, which is 5-15 mm smaller than the diameter of the heat exchange tube. In addition, the distribution of the heat exchange tube holes is triangular or square. It is characterized in that the small circular holes are distributed between the tube hole arrays, and the small circular holes are arranged in two rows, but not limited to two rows, and further each row of small circular holes is evenly distributed between two adjacent rows of tube hole arrays, and two rows of small circular holes are distributed between three adjacent rows of tube hole arrays; the position of the small circular holes can be close to the notch or far away from the notch, for example Figure 2 、 Figure 3 .

[0007] The present invention has a small hole bow baffle shell and tube floating head heat exchanger. Figure 4, comprising a second cylinder (5'), the second cylinder (5') having a second shell-side fluid inlet (4') and a second shell-side fluid outlet (13') respectively opened at both ends, one end of the second cylinder (5') being connected to the second fixed tube sheet (3') through a flange, the outer side of the tube sheet being connected to the second pipe box (1'), i.e., the left pipe box, the second pipe box (1') having a second tube-side fluid inlet (17') and a second tube-side fluid outlet (2') respectively opened, the other end of the second cylinder (5') being connected to the second floating head pipe box (9'), i.e., the right pipe box, through a second floating head flange (10'), the second floating head pipe box (9') having The second floating head tube sheet (11') is connected to the floating head cover plate by a second hook ring (12') and a second floating head flange (10'). The second cylinder (5') contains a second heat exchange tube bundle (8'), a second bow-shaped baffle (7'), and a second baffle tube (14') located at the center of the cylinder. The second bow-shaped baffle (7') is perpendicular to the tube axis and is fixed in parallel along the axial direction by a second tie rod (15') and a second distance tube (6'). The second tie rod (15') is fixed to the second tube sheet (3'). The second bow-shaped baffle (7') is provided with a small circular hole. When the bow-shaped baffle tube shell-type floating head flow plate heat exchanger with small holes of the present invention is in operation, after the shell-side fluid enters the shell, a portion of the fluid flows in a "Z" shape under the guidance of the bow-shaped baffle, and the other portion of the fluid passes through the small holes on the baffle and passes through other baffles in the same manner to exchange heat with the tube-side fluid.

[0008] In actual application, the second cylinder (5') is generally placed on the second saddle (16'). The heat exchange tube holes on the second bow-shaped baffle (7') with small holes are arranged according to conventional technology, wherein the diameter of the heat exchange tube holes is designed according to the heat exchanger standard GB151, and the diameter of the small circular hole varies according to the diameter of the heat exchange tube, which is 5-15mm smaller than the diameter of the heat exchange tube. In addition, the distribution of the heat exchange tube holes is triangular or square. It is characterized in that the small circular holes are distributed between the tube hole arrays, and the small circular holes are arranged in two rows, but not limited to two rows, and further each row of small circular holes is evenly distributed between two adjacent rows of tube hole arrays, and two rows of small circular holes are distributed between three adjacent rows of tube hole arrays; the position of the small circular holes can be close to the notch or far away from the notch, for example Figure 5 、 Figure 6 .

[0009] The present invention has a small circular hole with the bow baffle shell and tube type U-tube heat exchanger Figure 7, comprising a third cylinder (5"), a third shell-side fluid inlet (4") and a third shell-side fluid outlet (8") are respectively provided at both ends of the third cylinder (5"), one end of the third cylinder (5") is connected to a third fixed tube sheet (3") through a flange, the outer side of the tube sheet is connected to a third pipe box (1"), a third tube-side fluid inlet (12") and a third tube-side fluid outlet (2") are respectively provided on the third pipe box (1"), a third U-shaped tube bundle (7") and a third bow-shaped baffle (6") are arranged in the third cylinder (5"), the baffle is perpendicular to the tube axis and is uniformly fixed in parallel along the axial direction by a third tie rod (11") and a third distance tube (10"), the third tie rod (11") is fixed on the third fixed tube sheet (3"), and the third bow-shaped baffle (6") has a small circular hole. When the shell-and-tube U-tube heat exchanger with the bow-shaped baffles and small holes of the present invention is in operation, after the shell-side fluid enters the shell, a portion of the fluid flows in a "Z" shape under the guidance of the bow-shaped baffles, and the other portion of the fluid passes through the small holes on the baffles and passes through other baffles in the same manner to exchange heat with the tube-side fluid.

[0010] In practical applications, the third cylinder (5") is generally placed on the third saddle (9"). The heat exchange tube holes on the third bow-shaped baffle (6") with small holes are arranged according to conventional technology, wherein the diameter of the heat exchange tube holes is designed according to the heat exchanger standard GB151, and the diameter of the small circular holes varies according to the diameter of the heat exchange tubes, and is 5-15 mm smaller than the diameter of the heat exchange tubes. In addition, the distribution of the heat exchange tube holes is triangular or square. It is characterized in that the small circular holes are distributed between the tube hole arrays, and the small circular holes are arranged in two rows, but not limited to two rows. Further, each row of small circular holes is evenly distributed between two adjacent rows of tube hole arrays, and the two rows of small circular holes are distributed between three adjacent rows of tube hole arrays; the position of the small circular holes can be close to the notch or far away from the notch, for example Figure 8 、 Figure 9 .

[0011] Effects of the Invention: This invention changes the fluid flow in traditional bow-shaped baffle heat exchangers from transverse flow perpendicular to the tube bundle to a mixed flow combining transverse and longitudinal flow, significantly reducing pressure drop, significantly minimizing flow "dead zones," improving heat transfer efficiency, and mitigating tube bundle vibration and wear. Under identical conditions, the shell-and-tube heat exchanger with bow-shaped baffles and small circular holes provided by the present invention improves shell-side heat transfer efficiency by 10%-20% and reduces shell-side pressure drop by 2%-10% compared to traditional bow-shaped baffle shell-and-tube heat exchangers. This also maintains the advantages of bow-shaped baffles for easy processing, installation, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Structural diagram of shell and tube fixed tube sheet heat exchanger with bow-shaped baffles and small holes

[0013] 1 is the first tube box, 2 is the first tube sheet, 3 is the first cylinder, 4 is the first baffle, 5 is the first distance tube, 6 is the first heat exchange tube bundle, 7 is the first shell-side fluid inlet, 8 is the first tube-side fluid outlet, 9 is the first saddle, 10 is the first tie rod, 11 is the first shell-side fluid outlet, and 12 is the first tube-side fluid inlet.

[0014] Figure 2 This is a schematic diagram of the distribution of the small circular holes on the baffle when they are located away from the arched notch.

[0015] Figure 3 This is a schematic diagram of the distribution of the small circular holes on the baffle when they are close to the arched notch.

[0016] Figure 4 Structural diagram of shell and tube floating head heat exchanger with bow-shaped baffles and small holes

[0017] 1' is the second pipe box, 2' is the second tube-side fluid outlet, 3' is the second fixed tube sheet, 4' is the second shell-side fluid inlet, 5' is the second shell, 6' is the second distance tube, 7' is the second baffle, 8' is the second heat exchange tube bundle, 9' is the second floating head pipe box, 10' is the second floating head flange, 11' is the second floating head tube sheet, 12' is the second hook ring, 13' is the second shell-side fluid outlet, 14' is the second intermediate baffle, 15' is the second pull rod, 16' is the second saddle, and 17' is the second tube-side fluid inlet.

[0018] Figure 5 This is a schematic diagram of the distribution of the small circular holes on the baffle when they are located away from the arched notch.

[0019] Figure 6 This is a schematic diagram of the distribution of the small circular holes on the baffle when they are close to the arched notch.

[0020] Figure 7 Structural diagram of shell and tube U-tube heat exchanger with bowed baffles and small holes

[0021] 1" is the third pipe box, 2" is the third tube-side fluid outlet, 3" is the third fixed tube sheet, 4" is the third shell-side fluid inlet, 5" is the third shell, 6" is the third baffle, 7" is the third heat exchange tube bundle, 8" is the third shell-side fluid outlet, 9" is the third saddle, 10" is the third distance tube, 11" is the third tie rod, and 12" is the third tube-side fluid inlet.

[0022] Figure 8 This is a schematic diagram of the distribution of the small circular holes on the baffle when they are located away from the arched notch.

[0023] Figure 9 This is a schematic diagram of the distribution of the small circular holes on the baffle when they are close to the arched notch.

[0024] Figure 10 The hole structure and corresponding size of the baffle corresponding to Example 1. DETAILED DESCRIPTION

[0025] The present invention is further described below with examples, but the present invention is not limited to the following examples.

[0026] Example 1

[0027] Numerical simulations are conducted on the shell-side fluid flow and heat transfer of a shell-and-tube fixed tube-sheet heat exchanger with bowed baffles and small holes.

[0028] The shell side of the shell-and-tube fixed tube sheet heat exchanger with bow-shaped baffles and small holes includes: a cylinder placed on a saddle, with a shell-side fluid inlet and a shell-side fluid outlet respectively opened at both ends of the cylinder, fixed tube sheets at both ends of the cylinder, a heat exchange tube bundle and bow-shaped baffles with small holes in the cylinder, the heat exchange tubes are distributed in a square shape, and the bow-shaped baffles with small holes are evenly arranged perpendicular to the tube axis.

[0029] The shell inner diameter of the fixed tube sheet heat exchanger with bow-shaped baffles and small holes is 500mm, the heat exchange tube specification is φ25×2.5, the number of tubes is 129, the distance between the centers of two adjacent holes is 32mm, the baffle spacing is 168mm, the height of the notch of the bow-shaped baffle is 125mm, the diameter of the small hole is 11mm, the small hole is located between the two heat exchange tube holes, and the distance between two adjacent small holes in each row is 32mm. Figure 10 As shown in the figure, the shell-side fluid is water, with an inlet temperature of 22°C and an inlet fluid velocity of 1.5 m / s. The heat exchange tube wall temperature is set to a constant 77°C. After heat exchange, the shell-side fluid outlet temperature is 58.87°C.

[0030] Compared with the ordinary bow-shaped baffle fixed tube sheet heat exchanger, the shell side heat transfer coefficient is increased by 10.14% and the shell side pressure drop is reduced by 8.53%.

[0031] By using the above-mentioned bowed baffles with small holes and corresponding conditions, the shell-side heat transfer coefficient of the shell-and-tube floating head heat exchanger with bowed baffles with small holes and the shell-and-tube U-tube heat exchanger with bowed baffles with small circular holes are increased by about 10%, and the shell-side pressure drop is reduced by about 8%.

Claims

1. A heat exchanger with an arcuate baffle with small holes, characterized in that: The invention relates to a shell and tube type fixed tube sheet heat exchanger with an arched baffle with small holes, comprising a first cylinder (3), a first shell-side fluid inlet (7) and a first shell-side fluid outlet (11) respectively provided at both ends of the first cylinder (3), a first fixed tube sheet (2) provided at both ends of the first cylinder (3), two first tube boxes (1) respectively connected to the outer sides of the two tube sheets, the two first tube boxes (1) respectively provided with a first tube-side fluid inlet (8) and a first tube fluid outlet (12), a first heat exchange tube bundle (6) and a first arched baffle (4) provided in the first cylinder (3), the baffle being perpendicular to the tube bundle and being fixed axially and parallelly by a first tie rod (10) and a first distance tube (5), the first tie rod (10) being fixed on the first fixed tube sheet (2), the first arched baffle (4) being provided with small circular holes, the small circular holes being distributed between the tube hole arrays, the small circular holes being arranged in two rows, and each row of small circular holes being evenly distributed between two adjacent rows of tube hole arrays, The two rows of small circular holes are located between the 1st to 3rd rows of tube holes on the side away from the notch; the diameter of the small circular holes varies according to the diameter of the heat exchange tube and is 5-15 mm smaller than the diameter of the heat exchange tube.

2. The segmented baffle heat exchanger with small holes according to claim 1, characterized in that: The diameter of the heat exchange tube holes on the first bow-shaped baffle (4) with small holes is designed according to the heat exchanger standard GB151, and the distribution of the heat exchange tube holes is triangular or square.

3. A heat exchanger with an arcuate baffle with small holes, characterized in that: The invention relates to a shell and tube floating head heat exchanger with an arcuate baffle having small holes, comprising a second cylinder (5'), with a second shell-side fluid inlet (4') and a second shell-side fluid outlet (13') respectively provided at both ends of the cylinder; one end of the second cylinder (5') is connected to a second fixed tube sheet (3') via a flange; the outer side of the tube sheet is connected to a second tube box (1'), i.e., a left tube box; the second tube box (1') is provided with a second tube-side fluid inlet (17') and a second tube-side fluid outlet (2'); the other end of the second cylinder (5') is connected to a second floating head tube box (9'), i.e., a right tube box, via a second floating head flange (10'); a second floating head tube sheet (11') is provided in the second floating head tube box (9'); the second floating head tube sheet (11') is connected to the second fixed tube sheet (3') via a flange; and the second fixed tube sheet (3') is connected to the second fixed tube sheet (3') via a flange; and the second fixed tube sheet (3') is connected to the second fixed tube box ... 12') and a second floating head flange (10') are connected to the floating head cover plate, a second heat exchange tube bundle (8'), a second bow-shaped baffle (7') and a second baffle tube (14') located at the center of the cylinder are arranged in the second cylinder (5'), the second bow-shaped baffle (7') is perpendicular to the tube axis and is fixed by a second tie rod (15') and a second distance tube (6') in parallel and evenly distributed along the axial direction, the second tie rod (15') is fixed on the second fixed tube sheet (3'), the second bow-shaped baffle (7') is provided with small circular holes, the small circular holes are distributed between the tube hole arrays, the small circular holes are arranged in two rows, each row of small circular holes is evenly distributed between two adjacent rows of tube hole arrays, and the positions of the two rows of small circular holes are distributed between the first to third rows of tube holes on the side away from the notch; The diameter of the small circular hole varies according to the diameter of the heat exchange tube and is 5-15mm smaller than the diameter of the heat exchange tube.

4. The segmented baffle heat exchanger with small holes according to claim 3, characterized in that: The diameter of the heat exchange tube holes on the second bow-shaped baffle (7') with small holes is designed according to the heat exchanger standard GB151, and the distribution of the heat exchange tube holes is triangular or square.

5. A heat exchanger with an arcuate baffle with small holes, characterized in that: The invention relates to a shell-and-tube type U-tube heat exchanger with an arcuate baffle and a small circular hole, comprising a third cylinder (5"), a third shell-side fluid inlet (4") and a third shell-side fluid outlet (8") respectively provided at both ends of the third cylinder (5"), one end of the third cylinder (5") being connected to a third fixed tube sheet (3") via a flange, the outer side of the tube sheet being connected to a third tube box (1"), a third tube box (1") being provided with a third tube-side fluid inlet (12") and a third tube-side fluid outlet (2") respectively, and a third U-shaped tube bundle being arranged in the third cylinder (5") (7") and a third bow-shaped baffle (6"), the baffle is perpendicular to the tube axis and is fixed uniformly along the axial direction by a third tie rod (11") and a third distance tube (10"), the third tie rod (11") is fixed on the third fixed tube sheet (3"), and the third bow-shaped baffle (6") has small circular holes; the small circular holes are distributed between the tube hole arrays, the small circular holes are arranged in two rows, each row of small circular holes is evenly distributed between the two adjacent rows of tube hole arrays, and the positions of the two rows of small circular holes are distributed between the 1st to 3rd rows of tube holes on the side away from the notch; The diameter of the small circular hole varies according to the diameter of the heat exchange tube and is 5-15mm smaller than the diameter of the heat exchange tube.

6. The segmental baffle heat exchanger with small holes according to claim 5, characterized in that: The diameter of the heat exchange tube holes on the third bow-shaped baffle (6") with small holes is designed according to the heat exchanger standard GB151, and the distribution of the heat exchange tube holes is triangular or square.

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