A four-pass plate-tube heat exchanger and a method of using the same

Abstract

The present invention discloses a four-pass plate-and-tube heat exchanger, comprising a cylinder, both ends of which are fixed with end plates to form a heat exchanger shell; a partition is fixed in the shell along its axial direction, and the partition divides the shell into a plate-pass heat exchange chamber and a tube-pass heat exchange chamber; a plurality of heat exchange plates are arranged in parallel with the end plates in the plate-pass heat exchange chamber; four through holes are opened on the heat exchange plates and the end plates, and the through holes are fixed with fluid distribution inlet and outlet pipes, and the heat exchange plates, the end plates, the cylinder and the partition together form a plurality of small cavities, and each small cavity has two fluid distribution holes on the fluid distribution inlet and outlet pipes leaking out, thereby forming a phase-changeable gas condensation chamber and a cooling liquid chamber that are alternate with each other. The four-pass plate-and-tube heat exchanger and the use method disclosed by the present invention save space and improve heat exchange efficiency because circulating coolant and low-temperature coolant are used in one heat exchanger to perform heat exchange, condensation and cooling on the phase-changeable fluid at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange equipment, and more particularly to a four-flow plate-and-tube heat exchanger and a method for using the same. Background Art

[0002] Heat exchanger is a device that transfers part of the heat of hot fluid to cold fluid. It is also called heat exchanger. Heat exchanger plays an important role in chemical, petroleum, power, food and many other industrial production. In chemical production, heat exchanger can be used as heater, cooler, condenser, evaporator and reboiler, etc., and is widely used.

[0003] At present, the heat exchangers currently used cannot guarantee sufficient heat exchange and precise temperature control for heat exchange processes with phase change. Even for double-pass tube-sheet heat exchangers, because the plate-side and tube-side heat exchange use the same coolant, the temperature of the outflowing liquid cannot be precisely controlled. Multiple heat exchangers need to be connected in parallel or in series and work continuously to complete the process, which increases the overall cost and occupied space of the entire heat exchange system.

[0004] Therefore, how to provide a four-flow plate and tube heat exchanger and a method for using the same is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] In view of this, the present invention provides a four-pass plate and tube heat exchanger and a method for using the same, in which circulating coolant and low-temperature coolant are used in one heat exchanger to perform heat exchange, condensation and cooling on a phase-changeable fluid, which can not only save space and improve heat exchange efficiency, but also accurately control the temperature of the outflowing condensed liquid by controlling the exchange area of ​​the plate side and the tube side and the temperature and flow rate of the two coolants.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A four-pass plate-and-tube heat exchanger, comprising a cylinder, both ends of which are fixed with end plates to form a heat exchanger shell; a partition is fixed in the shell along its axial direction, and the partition divides the shell into a plate-pass heat exchange chamber and a tube-pass heat exchange chamber; a plurality of heat exchange plates are arranged in parallel with the end plates in the plate-pass heat exchange chamber; four through holes are opened in the heat exchange plates and the end plates, and the through holes are fixed with fluid collecting and distributing inlet and outlet pipes, and the heat exchange plates, the end plates, the cylinder and the partition together form a plurality of small cavities, and each of the small cavities has two fluids on the fluid collecting and distributing inlet and outlet pipes The collecting and distributing holes leak out, thereby forming a phase-changeable gas condensation chamber and a cooling liquid chamber alternately spaced from each other; a plurality of heat exchange tubes are fixedly arranged vertically to the end plate in the tube-side heat exchange chamber, and holes are opened near the two end plates of the cylinder and fixedly connected with a low-temperature coolant inlet pipe and a low-temperature coolant outflow pipe; a semi-cap is fixed at both ends of the cylinder corresponding to the tube-side heat exchange chamber, and both ends of the plurality of heat exchange tubes pass through the end plate and are communicated with the inner cavity of the semi-cap, and the semi-caps on both sides are respectively connected with a condensate inlet pipe and a cooling condensate outflow pipe; and the condensate inlet pipe is connected with one of the fluid collecting and distributing inlet and outlet pipes.

[0008] In the four-pass plate-and-tube heat exchanger disclosed in the present invention, the phase-changeable gas is condensed after heat exchange in the plate-pass heat exchange chamber, and the condensed liquid enters the tube-pass heat exchange chamber for heat exchange, and finally flows out from the cooling condensate outflow pipe; the phase-changeable gas uses circulating coolant and low-temperature coolant in one heat exchanger to condense and cool the phase-changeable fluid for heat exchange, which not only saves space and improves heat exchange efficiency, but also controls the exchange area of ​​the plate-pass and tube-pass and the temperature and flow rate of the two coolants, thereby accurately controlling the temperature of the outflowing condensed liquid.

[0009] Preferably, the four through holes opened on the heat exchange plate and the end plate are respectively an air flow hole, a condensate outflow hole, a coolant inflow hole and a coolant outflow hole; the air flow hole, the condensate outflow hole, the coolant inflow hole and the coolant outflow hole respectively correspond to the fluid collecting and distributing inlet and outlet pipes passing through them, which are respectively a gas inlet pipe, a condensate outflow pipe, a coolant inflow pipe and a coolant outflow pipe; the condensate outflow pipe is connected with the condensate inflow pipe through a connecting pipe.

[0010] The beneficial effect of adopting the above technical solution is that the four tubes with different functions, namely the gas inlet tube, the condensate outlet tube, the coolant inlet tube and the coolant outlet tube, are all completed by the fluid distribution inlet and outlet tubes and are used in pairs, and the fluid distribution holes of each pair of tubes are exactly staggered with the fluid distribution holes of the other pair of tubes; the gas inlet tube and the condensate outlet tube are paired, and the coolant inlet tube and the coolant outlet tube are paired, so as to correspond to the phase-changeable gas condensation cavity and the cooling liquid cavity respectively.

[0011] Preferably, the aperture and spacing distance of the fluid collecting and distributing holes are equal.

[0012] The beneficial effect of adopting the above technical solution is that the fluid collecting and dispersing holes are evenly distributed, making the heat exchange more uniform.

[0013] Preferably, the interval between adjacent fluid collecting and distributing holes is at least greater than the thickness of the heat exchange plate.

[0014] The beneficial effect of adopting the above technical solution is to ensure that the phase-changeable gas condensation chamber and the cooling liquid chamber form independent chambers.

[0015] Preferably, an upper guide plate and a lower guide plate perpendicular to the heat exchange tube are provided on the heat exchange tube, and the lowest end of the upper guide plate is lower than the highest end of the lower guide plate.

[0016] The beneficial effect of adopting the above technical solution is that the low-temperature coolant can be evenly distributed inside the heat exchange cavity of the tube side, thereby ensuring uniform heat exchange.

[0017] Preferably, the semi-head is fixed to both ends of the cylinder by means of an inner flange, an outer flange, bolts and nuts, and its fixed position is on the outer side of the end plate corresponding to the tube-side heat exchange cavity; a semi-head gasket is arranged between the semi-head and the end plate.

[0018] The beneficial effect of adopting the above technical solution is that the inner flange, outer flange, bolts and nuts can ensure a firm connection between the semi-head and the end plate, and the semi-head gasket can prevent the condensate in the semi-head from leaking out.

[0019] Preferably, the semi-end cap is a semi-circular arc-shaped body with an inner cavity, including an arc-shaped portion and a flat plate portion, and the arc-shaped portion is provided with a condensate inlet and outlet.

[0020] The beneficial effect of adopting the above technical solution is that it is convenient for the condensed liquid in the heat exchange tube to be collected and then flow out through the cooling condensed liquid outflow pipe.

[0021] Preferably, the partition is fixed to the cylinder by welding, and the two ends of the connecting pipe are respectively fixed to the condensate outflow pipe and the condensate inflow pipe.

[0022] The beneficial effects of adopting the above technical solution are that the welding fixation is firm and the process is simple.

[0023] Preferably, the end plate is provided with a plurality of heat exchange tube holes at positions corresponding to the heat exchange tubes, and the fluid collecting and distributing holes are square holes or round holes.

[0024] The beneficial effect of adopting the above technical solution is that the multiple heat exchange tube holes are used for the condensate in the heat exchange tube to flow into the inner cavity of the semi-head; the shape of the fluid collecting and distributing holes can be freely selected according to actual needs.

[0025] The present invention also discloses a method for using a four-flow plate-and-tube heat exchanger. After the phase-changeable gas enters the plate-side heat exchange cavity from the gas inlet pipe, the cooling liquid cavity and the phase-changeable gas condensation cavity are arranged alternately with each other. The phase-changeable gas is condensed after entering the plate-side heat exchange cavity. The condensed liquid passes through the condensate outlet pipe, the connecting pipe and the condensate inlet pipe into the tube-side heat exchanger for heat exchange, and finally flows out from the cooling condensate outlet pipe.

[0026] It can be seen from the above technical solution that, compared with the prior art, the present invention discloses a four-pass plate and tube heat exchanger and a method of using the same, which can simultaneously use circulating coolant and low-temperature coolant in one heat exchanger to perform heat exchange, condensation and cooling on a phase-changeable fluid, which can not only save space and improve heat exchange efficiency, but also, by controlling the exchange area of ​​the plate pass and the tube pass and the temperature and flow rate of the two coolants, the temperature of the outflowing condensed liquid can be precisely controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 This is a schematic diagram of the appearance of the four-flow plate and tube heat exchanger provided by the present invention.

[0029] Figure 2 This is a schematic diagram of the internal structure of the four-flow plate and tube heat exchanger provided by the present invention.

[0030] Figure 3 A side schematic diagram of a four-flow plate and tube heat exchanger provided by the present invention.

[0031] Figure 4 A schematic diagram of fluid flow and heat exchange of four fluids in a heat exchanger provided by the present invention.

[0032] Figure 5 This is a schematic diagram of the heat exchange plate provided by the present invention.

[0033] Figure 6 This is a schematic diagram of the fluid collecting and distributing inlet and outlet pipes provided by the present invention.

[0034] Figure 7 This is a schematic diagram of a half head provided by the present invention.

[0035] Figure 8 This is a partial enlarged view of the internal structure of the plate-pass heat exchange chamber provided by the present invention.

[0036] Fig. 9This is a schematic diagram of the end plate provided by the present invention.

[0037] Wherein, each figure is marked as:

[0038] 1-cylinder, 2-end plate, 3-heat exchange plate, 4-partition, 5-semi-end, 6-end gasket, 7-lower guide plate, 8-upper guide plate, 9-gas inlet pipe, 10-condensate outlet pipe, 11-coolant inlet pipe, 12-coolant outlet pipe, 13-condensate inlet pipe, 14-cooling condensate outlet pipe, 15-low-temperature coolant inlet pipe, 16-low-temperature coolant outlet pipe, 17-connecting pipe, 18-inner flange, 19-outer flange, 20 bolts, 21 nuts, 22-air flow hole, 23-condensate outlet hole, 24-coolant inlet hole, 25-coolant outlet hole, 26-fluid distribution inlet and outlet pipe, 27-heat exchange tube, 28-fluid distribution hole, 29-outside of semi-end flange, 30- Inside the semi-end flange, 31-phase-changeable gas condensation chamber, 32-cooling liquid chamber, 33-condensate inlet and outlet, 34-heat exchange tube hole, 51-arc-shaped part, 52-flat plate part. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Depend on Figure 1 , 2 , 3, and 4 show that an embodiment of the present invention discloses a four-flow plate and tube heat exchanger, comprising: a cylinder 1, an end plate 2, a heat exchange plate 3, a partition 4, a semi-end head 5, a semi-end head gasket 6, a lower guide plate 7, an upper guide plate 8, a gas inlet pipe 9, a condensate outlet pipe 10, a coolant inlet pipe 11, a coolant outlet pipe 12, a condensate inlet pipe 13, a cooling condensate outlet pipe 14, a low-temperature coolant inlet pipe 15, a low-temperature coolant outlet pipe 16, a connecting pipe 17, an inner flange 18, an outer flange 19, a fluid collecting and distributing inlet and outlet pipe 26, and a heat exchange tube 27. End plates 2 are fixed at both ends of the cylinder 1 to form a heat exchanger shell; a partition plate 4 is fixed in the shell along its axial direction, and the partition plate 4 divides the shell into a plate-side heat exchange chamber and a tube-side heat exchange chamber; a plurality of heat exchange plates 3 are arranged in parallel with the end plate 2 in the plate-side heat exchange chamber; four through holes are opened on the heat exchange plates 4 and the end plates 5, and the through holes are fixed with fluid distribution inlet and outlet pipes 26, and the heat exchange plates 3, the end plates 2, the cylinder 1 and the partition plate 4 together form a plurality of small cavities, and each small cavity has two fluid distribution holes 28 on the fluid distribution inlet and outlet pipes 26 leaking out, thereby forming a phase-changeable gas condensation chamber and a cooling liquid chamber alternately spaced from each other;

[0041] A plurality of heat exchange tubes 27 are vertically fixed to the end plate 2 in the tube-side heat exchange cavity. Holes are opened in the cylinder 1 near the two end plates 2 and fixedly connected with a low-temperature coolant inlet pipe 15 and a low-temperature coolant outflow pipe 16. Semi-end caps 5 are fixed at the two ends of the cylinder 1 corresponding to the tube-side heat exchange cavity. Both ends of the plurality of heat exchange tubes 27 penetrate the end plate 2 and communicate with the inner cavity of the semi-end caps 5, and the semi-end caps on both sides are respectively connected with a condensate inlet pipe 13 and a cooling condensate outflow pipe 14; and the condensate inlet pipe 13 is connected to one of the fluid collecting and distributing inlet and outlet pipes 26.

[0042] The four-pass plate-and-tube heat exchanger is specifically implemented in the following steps: first, end plates 2 are welded at both ends of the cylinder 1 to form a heat exchanger shell, and a partition plate 4 is welded inside the shell to divide the shell into two cavities, namely a plate-side heat exchange cavity and a tube-side heat exchange cavity. In one of the cavities, at least three heat exchange plates 3 are arranged parallel to the end plate 2 to form a plate-side heat exchange cavity: in the other cavity, a plurality of heat exchange tubes 27 are arranged perpendicular to the end plate 2, and both ends of each heat exchange tube 27 are welded and fixed to the end plates 2 at both ends of the cylinder 1 to form a tube-side heat exchange cavity.

[0043] Secondly, see Figure 5 and Fig. 9 Four holes with the same diameter are respectively opened on the two end plates 2 and all the heat exchange plates 3, namely the air flow hole 22, the condensate outflow hole 23, the coolant inflow hole 24, and the coolant outflow hole 25. The four holes on all the heat exchange plates 3 are respectively welded to the four fluid collecting and distributing inlet and outlet pipes 26, and the heat exchange plates are welded to the inner wall of the cylinder 1 and one side of the partition 4.

[0044] Further, see Figure 8 The plate heat exchange cavity is composed of multiple heat exchange plates 3, fluid distribution inlet and outlet pipes 26, cylinder 1 and partition 4 to form multiple small cavities. In each small cavity, only two fluid distribution holes 28 on the fluid distribution inlet and outlet pipes 26 can leak out, thereby forming a phase-changeable gas condensation cavity 31 and a cooling liquid cavity 32 arranged alternately with each other.

[0045] Further, see Figure 6 , the fluid collecting and distributing inlet and outlet pipe 26 is blocked at one end, and fluid collecting and distributing holes 28 are evenly spaced along the length of the pipe. Preferably, the hole diameter and the spacing are equal. They can be circular holes or polygonal holes, preferably square holes. The spacing between adjacent holes must be at least greater than the thickness of the heat exchange plate 3. The hole diameter and hole spacing are determined by heat exchange balance calculation.

[0046] Further, see Figure 2 and Fig. 9The tube-side heat exchange cavity is formed by opening two holes on the side of the cylinder 1 close to the two end plates 2 and welding a low-temperature coolant inlet pipe 15 and a low-temperature coolant outlet pipe 16, and setting several upper guide plates 8 and lower guide plates 7 on several heat exchange tubes 27.

[0047] Further, see Figure 1 , Figure 2 and Figure 7 The two half heads 5 are fixed respectively by welding the inner flanges 18 at both ends of the cylinder 1 and the outer flanges 19, bolts 20 and nuts 21, and the fixing position is outside the end plate 2 corresponding to the heat exchange cavity of the tube side. Figure 7 As shown, the semi-end cap 5 is a semi-circular arc-shaped body with an inner cavity, including an arc-shaped portion 51 and a flat portion 52, and the installation method is that the outer side 29 of the semi-end cap flange is close to the outer flange 19, and the inner side 30 of the semi-end cap flange is installed close to the inner flange 18. The arc-shaped portion 51 is provided with a condensate inlet and outlet 33, and the condensate inlet and outlet 33 are respectively connected to the condensate inlet pipe 13 and the cooling condensate outflow pipe 14. A semi-end cap gasket 6 is arranged between the semi-end cap 5 and the end plate 2. The condensate inlet pipe 13 and the cooling condensate outflow pipe 14 are welded on the outer sides of the two semi-end caps 5.

[0048] Furthermore, a connecting pipe 17 is welded between the condensate outflow pipe 10 and the condensate inflow pipe 13 .

[0049] It needs to be further explained that the four tubes with different functions, namely the gas inlet tube 9, the condensate outlet tube 10, the coolant inlet tube 11 and the coolant outlet tube 12, are all completed by the fluid distribution inlet and outlet tube 26, but are used in pairs, and the fluid distribution holes 28 of each pair of tubes are exactly staggered with those of the other pair of tubes.

[0050] The use process of the four-process plate-and-tube heat exchanger disclosed in the present invention is as follows: after the phase-changeable gas enters the plate-side heat exchange cavity from the gas inlet pipe 9, the phase-changeable gas is condensed after entering the plate-side heat exchange cavity because the cooling liquid cavity 32 and the phase-changeable gas condensation cavity 31 are arranged alternately with each other. The condensed liquid enters the tube-side heat exchanger through the condensate outlet pipe 10, the connecting pipe 17 and the condensate inlet pipe 13 for heat exchange, and finally flows out from the cooling condensate outlet pipe 14, thereby realizing heat exchange, condensation and cooling of the phase-changeable fluid by using circulating coolant and low-temperature coolant in the same heat exchanger, which not only saves space and improves heat exchange efficiency, but also controls the exchange area of ​​the plate side and the tube side and the temperature and flow rate of the two coolants, thereby accurately controlling the temperature of the outflowing condensed liquid.

[0051] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0052] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A four-pass plate and tube heat exchanger, characterized in that: It comprises a cylinder (1), with end plates (2) fixed at both ends of the cylinder (1) to form a heat exchanger shell; a partition plate (4) is fixed inside the shell along its axial direction, and the partition plate (4) divides the shell into a plate-side heat exchange chamber and a tube-side heat exchange chamber; A plurality of heat exchange plates (3) are arranged in parallel with the end plate (2) in the plate heat exchange cavity; four through holes are provided on the heat exchange plate (3) and the end plate (2), and a fluid collecting and distributing inlet and outlet pipe (26) is fixedly passed through the through holes; the heat exchange plate (3), the end plate (2), the cylinder (1) and the partition (4) together form a plurality of small cavities, and each of the small cavities has two fluid collecting and distributing holes (28) on the fluid collecting and distributing inlet and outlet pipe (26) leaking out, thereby forming a phase-changeable gas condensation cavity (31) and a cooling liquid cavity (32) alternately disposed with each other; A plurality of heat exchange tubes (27) are fixedly arranged vertically in the tube-side heat exchange cavity and the end plate (2); holes are opened in the cylinder (1) near the two end plates (2) and fixedly connected with a low-temperature coolant inlet pipe (15) and a low-temperature coolant outlet pipe (16); a semi-end cap (5) is fixedly arranged at the two ends of the cylinder (1) corresponding to the tube-side heat exchange cavity; the two ends of the plurality of heat exchange tubes (27) pass through the end plate (2) and are in communication with the inner cavity of the semi-end cap (5); and the semi-end caps (5) on both sides are respectively connected with a condensate inlet pipe (13) and a cooling condensate outlet pipe (14); and the condensate inlet pipe (13) is in communication with one of the fluid collecting and distributing inlet and outlet pipes (26); The four through holes formed on the heat exchange plate (3) and the end plate (2) are respectively an air flow hole (22), a condensate outflow hole (23), a coolant inflow hole (24) and a coolant outflow hole (25); the fluid collecting and distributing inlet and outlet pipes (26) passing through the air flow hole (22), the condensate outflow hole (23), the coolant inflow hole (24) and the coolant outflow hole (25) are respectively a gas inflow pipe (9), a condensate outflow pipe (10), a coolant inflow pipe (11) and a coolant outflow pipe (12); the condensate outflow pipe (10) is connected to the condensate inflow pipe (13) via a connecting pipe (17); After the phase-changeable gas enters the plate-side heat exchange chamber from the gas inlet pipe (9), the phase-changeable gas is condensed after entering the plate-side heat exchange chamber because the cooling liquid chamber (32) and the phase-changeable gas condensation chamber (31) are arranged alternately with each other. The condensed liquid enters the tube-side heat exchanger through the condensate outlet pipe (10), the connecting pipe (17) and the condensate inlet pipe (13) for heat exchange, and finally flows out from the cooling condensate outlet pipe (14).

2. A four-pass plate-and-tube heat exchanger according to claim 1, characterized in that: The aperture and spacing distance of the fluid collecting and dispersing holes (28) are equal.

3. A four-pass plate-and-tube heat exchanger according to claim 2, characterized in that: The interval between adjacent fluid collecting and dispersing holes (28) is at least greater than the thickness of the heat exchange plate (3).

4. A four-pass plate-and-tube heat exchanger according to claim 1, characterized in that: An upper guide plate (8) and a lower guide plate (7) perpendicular to the heat exchange tube (27) are provided on the heat exchange tube (27), and the lowest end of the upper guide plate (8) is lower than the highest end of the lower guide plate (7).

5. A four-pass plate-and-tube heat exchanger according to claim 1, characterized in that: The semi-end cap (5) is fixed to the two ends of the cylinder (1) by means of an inner flange (18), an outer flange (19), bolts (20) and nuts (21), and its fixing position is located on the outer side of the end plate (2) corresponding to the tube-side heat exchange cavity; a semi-end cap gasket (6) is provided between the semi-end cap (5) and the end plate (2).

6. A four-pass plate-and-tube heat exchanger according to claim 1, characterized in that: The semi-end cap (5) is a semicircular arc-shaped body with an inner cavity, comprising an arc-shaped portion (51) and a flat plate portion (52), and the arc-shaped portion (51) is provided with a condensate inlet and outlet (33).

7. A four-pass plate-and-tube heat exchanger according to claim 1, characterized in that: The partition plate (4) is fixed to the cylinder (1) by welding; and the two ends of the connecting pipe (17) are respectively fixed to the condensate outflow pipe (10) and the condensate inflow pipe (13).

8. The four-pass plate-and-tube heat exchanger according to claim 1, characterized in that: The end plate (2) is provided with a plurality of heat exchange tube holes (34) at positions corresponding to the heat exchange tubes (27); the fluid collecting and distributing holes (28) are square holes or round holes.

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