Steam heat exchange tube and steam-water mixing heat exchanger thereof

Abstract

The invention provides a steam heat exchange tube and a steam-water mixing heat exchanger thereof, the heat exchange tube comprises a tube body and spiral flow channel sheets arranged outside the tube body, one end of the heat exchange tube is opened for steam to flow in, the other end of the heat exchange tube is closed, steam outlet holes are formed in the tube body between the spiral flow channel sheets, and the steam in the heat exchange tube flows out through the steam outlet holes. Steam flows along the spiral flow channel and is fully mixed with liquid flowing outside, the turbulent flow effect of steam-liquid mixing is enhanced, and the steam-liquid heat exchange effect can be improved.

Description

Technical Field

[0001] The invention relates to a heat exchange tube and a heat exchanger thereof, in particular to a steam heat exchange tube and a steam-water mixed heat exchange heat exchanger thereof. Background Art

[0002] Shell and tube heat exchangers are widely used in industries such as chemical, petroleum, refrigeration, nuclear energy and power. Due to the global energy crisis, in order to reduce energy consumption, the demand for heat exchangers in industrial production is increasing, and the quality requirements for heat exchangers are also getting higher and higher. In recent decades, although compact heat exchangers (plate, plate-fin, press-welded plate heat exchangers, etc.), heat pipe heat exchangers, direct contact heat exchangers, etc. have developed rapidly, shell and tube heat exchangers still dominate production and usage due to their high reliability and wide adaptability. According to relevant statistics, the use of shell and tube heat exchangers in industrial devices still accounts for about 70% of all heat exchangers.

[0003] At present, people usually use heat exchangers to heat water. In various shell and tube and plate heat exchangers, steam and water go through different channels respectively, and the two realize heat exchange through good conductors. The water flow channels are generally coiled and tortuous to increase the contact area with the steam so that it can be fully heated. Therefore, there are defects such as complex structure, slow heating speed, high vibration and noise, and low thermal efficiency. Although the noise can be reduced to a certain extent by installing a silencer, the flow rate and flow velocity of the steam must be limited, and there are still shortcomings such as slow heating speed and low thermal efficiency.

[0004] There are also some related inventions of direct steam-liquid mixing heat exchange in the prior art, for example, CN104075590A discloses a silent steam-water mixing heat exchanger. This silent steam-water mixing heat exchanger has a main body, which is arranged as a water inlet end and a water outlet end along the water flow direction, and a steam inlet end is arranged on the side wall of the main body, and the water inlet end and the water outlet end are both cone structures, and a spray hole for steam spraying is arranged on the pipe wall of the water outlet end, and the angle between the axis of the spray hole and the axis of the pipe wall is 40-65°, and a packing layer for muteness is filled in the main body, and a filter screen is arranged at the steam inlet end, and a drain plug is arranged on the side wall of the main body corresponding to the steam inlet end. The present invention has a reasonable design, adopts a silent packing layer, is silent, has no vibration, is low in cost, is installed in a pipeline system, has high heating efficiency, and is easy to install and maintain, thereby improving work efficiency. CN202709791U discloses a composite soda-water mixing tank, which includes a tank body, a drain valve, a steam inlet, a cold water inlet, a porous partition, a thermostat interface, a water outlet, and a vent pipe, wherein the drain valve is arranged at the bottom of the tank body, the steam inlet is arranged at the side of the lower end of the tank body, the porous partition is installed inside the tank body, the cold water inlet is arranged at the side of the tank body, and it is located between the steam inlet and the porous partition, and the water outlet, the vent pipe and the thermostat interface are arranged at the top of the tank body. The utility model has made sufficient improvements on the scaling problem on the basis of the traditional mixing tank, is suitable for environments with high water hardness, can realize convenient disassembly and cleaning, and can solve the problem of waste heat recovery, and fundamentally prevents the occurrence of scaling and blockage.

[0005] In the prior art, there are many problems in the mixed heat exchange of steam and liquid, such as a single heat exchange tube, a small heat exchange area for the mixed heat exchange of steam and liquid, and poor steam and liquid mixing effect. The present application improves the heat exchange tube, adopts a new structure of the heat exchange tube and its heat exchanger, expands the heat exchange area, increases the mixing area, and achieves a better steam-liquid mixing effect. Summary of the invention

[0006] In order to overcome the defects and shortcomings in the prior art, the present invention provides a steam heat exchange tube and a vapor-liquid heat exchanger thereof, which can expand the heat exchange area and increase the mixing area, thereby effectively improving the heat transfer efficiency.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: A steam heat exchange tube comprises a tube body and a spiral flow channel sheet arranged outside the tube body. One end of the heat exchange tube is open for steam to flow in, and the other end is closed. Steam outlet holes are arranged on the tube body between the spiral flow channel sheets, and the steam in the heat exchange tube flows out through the steam outlet holes.

[0008] Preferably, the flow area of ​​the steam outlet hole increases continuously from one end to the other end of the heat exchange tube.

[0009] Preferably, the flow area of ​​the steam outlet hole increases increasingly from one end to the other end of the heat exchange tube.

[0010] Preferably, the ratio of the spacing between the spiral flow channel sheets to the height of the spiral flow channel sheets is 1:(1.5-2).

[0011] A steam-water mixing heat exchanger, the heat exchanger comprising a tube shell, a heat exchange tube, a liquid inlet pipe, an inlet head and an outlet head, the liquid inlet pipe is arranged on the tube shell, and a steam inlet pipe and a fluid outlet pipe are respectively arranged on the inlet head and the outlet head; an inlet tube sheet is arranged between the inlet head and the tube shell, and an outlet tube sheet is arranged between the outlet head and the tube shell, the heat exchange tube is arranged in the tube shell, the first end and the second end of the heat exchange tube are respectively fixedly connected to the inlet tube sheet and the outlet tube sheet, wherein the first end is connected to the inlet head, and the second end is not connected to the outlet head; a steam outlet hole for steam outflow is arranged on the tube wall of the heat exchange tube, and a through hole connecting the tube shell and the outlet head is arranged on the outlet tube sheet, characterized in that the heat exchange tube comprises a tube body and a spiral flow channel sheet arranged outside the tube body, steam outlet holes are arranged on the tube body between the spiral flow channel sheets, and the steam in the heat exchange tube flows out through the steam outlet holes.

[0012] Preferably, the flow area of ​​the steam outlet hole increases continuously from the inlet head to the outlet head.

[0013] Preferably, the flow area of ​​the steam outlet hole increases increasingly.

[0014] Preferably, the steam enters the heat exchange tube through the header from the steam inlet pipe, then comes out through the steam outlet hole of the heat exchange tube, mixes with the liquid entering through the liquid inlet pipe for heat exchange, and the fluid after heat exchange enters the outlet header through the through hole of the outlet tube sheet, and then flows out from the fluid outlet pipe.

[0015] Preferably, the ratio of the spacing between the spiral flow channel sheets to the height of the spiral flow channel sheets is 1:(1.5-2).

[0016] Preferably, the height of the spiral flow channel sheet is 0.3-0.4 times the outer diameter of the heat exchange tube.

[0017] Compared with the prior art, the present invention has the following advantages: The present invention provides a steam heat exchange tube with a spiral flow channel. Steam flows out from the steam hole of the heat exchange tube with the spiral flow channel structure, flows along the spiral flow channel, and is spirally mixed with the external flowing liquid. Moreover, because a part of the external fluid also flows along the spiral flow channel, the structure of the spiral flow channel causes the mixed fluid to change its flow direction when flowing therein, forming a vortex, thereby enhancing turbulence and mixing, enhancing the turbulence effect, and improving the mixing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 2. It is a schematic cross-sectional view of the spiral flow channel heat exchange tube structure of the heat exchanger of the present invention; Figure 2 It is a structural schematic diagram of a shell and tube heat exchanger of the present invention; Figure 3 It is a schematic diagram of a heat exchanger provided with a spiral flow channel heat exchange tube structure according to the present invention. DETAILED DESCRIPTION

[0019] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0020] In this article, unless otherwise specified, “ / ” represents division, and “×” and “*” represent multiplication.

[0021] Figure 1 A spiral flow channel steam heat exchange tube 2 is disclosed. Figure 1 As shown, the heat exchange tube 2 includes a tube body 25 and a spiral flow channel sheet 24 arranged outside the tube body. One end 21 of the heat exchange tube is open for steam to flow in, and the other end 22 is closed. Steam outlet holes 23 are arranged on the tube body between the spiral flow channel sheets 24. The steam in the heat exchange tube 2 flows out through the steam outlet holes 23 to mix with the external fluid for heat exchange.

[0022] The present invention provides a steam heat exchange tube with a spiral flow channel. Steam flows out from the steam hole of the heat exchange tube with the spiral flow channel structure, flows along the spiral flow channel, and is spirally mixed with the external flowing liquid. Moreover, because a part of the external fluid also flows along the spiral flow channel, the structure of the spiral flow channel causes the mixed fluid to change its flow direction when flowing therein, forming a vortex, thereby enhancing turbulence and mixing, enhancing the turbulence effect, and improving the mixing effect.

[0023] In addition, the provision of a spiral flow channel is equivalent to the provision of an external spiral fin, so that the external fluid and steam can also exchange heat indirectly through the wall of the heat exchange tube, further improving the effect of heat exchange mixing.

[0024] As an improvement, the diameter of the heat exchange tube and the shape and size of the spiral flow channel can be changed according to the flow rate of the vapor and liquid. In order to maintain a good mixing effect and make the steam and the external fluid mix more evenly, the height of the spiral flow channel sheet and the cylinder diameter, and the pitch and the cylinder diameter are kept at a certain data. Therefore, it is preferred that the spacing between adjacent spiral flow channel sheets and the height of the spiral flow channel sheet is 1: (1.5-2), and the height of the spiral flow channel sheet is 0.3-0.4 times the outer diameter of the heat exchange tube, maintaining a good turbulence effect and a good mixing effect.

[0025] As an improvement, the through hole area of ​​the steam outlet 23 of the heat exchange tube increases from the open end 21 to the closed end 22. By such a configuration, the flow area of ​​the steam outlet 23 of the heat exchange tube increases with the flow direction of the steam in the tube. By such a configuration, the heat exchange effect can be improved. Because the heat exchange between liquid and steam is divided into two parts, one part is the indirect heat exchange through the heat exchange tube, and the other part is the mixed heat exchange of steam and liquid coming out of the steam outlet 23. Because the steam inlet and the liquid inlet are in the same direction, for example Figure 2 , 3 , the above situation is to reduce the flow resistance. However, the above situation is actually equivalent to downstream heat exchange, and there is a problem of poor heat exchange effect. Moreover, because the pressure is higher near the steam inlet, the steam is easier to discharge, which also leads to uneven distribution of steam outlet volume front and back. Therefore, further improvement is needed. By setting the change of the distribution density of the steam outlet, the distribution of steam can be improved, so that the steam at the rear and the steam at the front are relatively evenly distributed or the steam distribution at the rear is more. Moreover, with the continuous flow, the temperature difference between the cold and hot fluids gradually decreases. By increasing the steam flow at the rear, the heat exchange per unit area is relatively uniform overall.

[0026] As an improvement, the through hole area of ​​the steam outlet hole 23 of the heat exchange tube increases from the open end 21 to the closed end 22 of the heat exchange tube, so that the steam output of the heat exchange tube per unit length gradually increases from the open end 21 to the closed end 22 of the heat exchange tube. With the continuous flow, the temperature difference between the cold and hot fluids gradually decreases, and the steam output of the heat exchange tube per unit length is gradually increased, thereby increasing the steam flow rate, and reducing the decrease in heat exchange caused by the decrease in temperature difference by increasing the flow rate, so that the heat exchange per unit length is relatively uniform as a whole, overcoming the problem of uneven heat exchange of the downstream heat exchanger, thereby achieving the technical effect of improving the heat exchange effect.

[0027] The present invention also provides a shell and tube heat exchanger for mixing steam and water, such as Figure 2 As shown, the shell and tube heat exchanger includes a tube shell 1, a heat exchange tube 2, a liquid inlet pipe 3, an inlet head 4 and an outlet head 5, the liquid inlet pipe 3 is arranged on the tube shell, and a steam inlet pipe 6 and a fluid outlet pipe 7 are respectively arranged on the inlet head 4 and the outlet head 5; an inlet tube sheet 8 is arranged between the inlet head 6 and the tube shell 1, and an outlet tube sheet 9 is arranged between the outlet head 7 and the tube shell 1, the heat exchange tube 2 is arranged in the tube shell 1, and the first end 21 and the second end 22 of the heat exchange tube are fixedly connected to the inlet tube sheet 8 and the outlet tube sheet 9 respectively, wherein the first end 21 is connected to the inlet head 4, and the second end 22 is not connected to the outlet head 5; a steam outlet hole 23 for steam outflow is arranged on the tube wall of the heat exchange tube 2, and a through hole 10 for connecting the tube shell and the outlet head is arranged on the outlet tube sheet.

[0028] The steam enters the heat exchange tube 2 from the steam inlet pipe 6 through the end cap 4, and then exits through the steam outlet hole 23 of the heat exchange tube 2. Because the second end of the heat exchange tube is a closed structure, the steam cannot directly enter the outlet end cap 5 through the second end, and therefore must flow out through the steam outlet hole 23. The liquid flows in from the liquid inlet pipe 3, and then directly mixes and exchanges heat with the steam flowing out of the steam outlet hole 23 in the tube shell 1. The fluid after heat exchange enters the outlet end cap through the through hole of the outlet tube sheet, and then flows out from the fluid outlet pipe.

[0029] The present invention proposes a heat exchanger for direct steam-water mixing heat exchange with a shell and tube heat exchanger structure. The heat exchanger can provide an expanded heat exchange area and increase the mixing area. Moreover, because of the shell and tube heat exchanger, the steam in the heat exchange tube can achieve indirect heat exchange with the liquid even inside the tube, so that the steam can achieve heat exchange with the liquid both inside and outside the tube, extending the heat exchange length and heat exchange area, so that more heat exchange area is distributed within a unit volume.

[0030] As an improvement, Figure 3 As shown, the heat exchange tube is Figure 1 Spiral channel heat exchange tube.

[0031] As an improvement, the height of the spiral channel sheet extending outward from the outer wall of the horizontal tube increases continuously from the inlet head 4 to the outlet head 5. Through the above arrangement, in the upstream of the liquid flow, because the blade height is small, the liquid can be fully mixed with the steam, and then as the height of the channel sheet increases, the fully mixed steam and water enter the spiral channel, and the rotation force becomes stronger and stronger, so that the rotation force of the airflow output at the rear becomes stronger and stronger, enhancing the rotation mixing effect at the rear, strengthening the heat exchange at the rear, thereby promoting the uniformity of the overall heat exchange and further improving the uniformity of mixing.

[0032] As an improvement, the height of the rotating channel sheet extending outward from the outer wall of the horizontal tube increases continuously from the inlet head 4 to the outlet head 5. By increasing the height continuously, the uniformity of mixing can be further improved.

[0033] As an improvement, the spiral flow channel sheets can be arranged at intervals. For example, the heat exchange pipe sections with spiral flow channel sheets and the heat exchange pipe sections without spiral flow channel sheets can be arranged at intervals. This allows the fluid to be mixed and disturbed in sections, reducing flow resistance, and can also destroy the laminar bottom layer in sections, improving the heat exchange effect.

[0034] As an improvement, the shell and tube heat exchanger is a horizontal shell and tube heat exchanger, wherein a plurality of through holes 10 are provided, and the distribution density of the through holes 10 is decreasing along the height direction from bottom to top. The purpose of setting the through hole density change is to achieve the change of the flow area of ​​the fluid after heat exchange, so that the flow area from bottom to top is gradually reduced. The main purposes are as follows. On the one hand, because the steam density is small, the discharged steam is not exchanged with heat in time, so it may gather in the upper part, thereby increasing the upper pressure. The steam is likely to be discharged directly through the upper through holes without mixing and heat exchange, thereby reducing the short circuit of heat exchange; on the other hand, because there is too much steam in the upper part, the pressure increases, but if no through holes are set, it will also make it difficult for the liquid to mix in the upper part. Therefore, it is necessary to set small flow through holes to reduce the pressure. At the same time, the flow area of ​​the through holes should be as small as possible to ensure the heat exchange effect; on the third hand, because the upper flow area is small, the steam flows from the lower part, and the liquid is more in the lower part due to gravity. Therefore, the liquid and steam are fully mixed in the lower part, and the accumulation of steam in the upper part is reduced, so that the heat exchange is uniform as a whole, the pressure in the shell and tube is reduced, and the purpose of sufficient mixing and heat exchange is further achieved.

[0035] As an improvement, along the height direction from bottom to top, the distribution density of the through holes 10 is gradually increasing. By changing the distribution density of the through holes, that is, changing the flow area, the overall heat exchange can be further uniform, the pressure in the tube shell can be reduced, and the purpose of fully mixing and heat exchange can be further achieved.

[0036] As an improvement, a plurality of baffles 11 are arranged in the tube shell, including a lower baffle located at the lower part of the tube shell and an upper baffle located at the upper part of the tube shell, and the lower baffles and the upper baffles are arranged at intervals. By arranging the baffles, the liquid flows in a zigzag manner, thereby improving the heat exchange effect.

[0037] As an improvement, the liquid inlet pipe 3 is arranged on a side close to the inlet head 4. By such an arrangement, the steam flow and the liquid flow directions can be made the same, thereby reducing the flow resistance.

[0038] As an improvement, Figure 2 As shown, the liquid inlet pipe is located at the lower part of the tube shell, and the baffle near the liquid inlet pipe is the lower baffle. Through the above arrangement, the inlet fluid must flow upward to avoid flowing from the lower part due to gravity, thereby improving the heat exchange effect.

[0039] As an improvement, the steam is water vapor, the liquid is cold water, and the fluid after heat exchange is hot water.

[0040] As an improvement, Figure 2As shown, the baffle near the outlet tube sheet is the lower baffle. And as a further improvement, the height of the baffle near the outlet tube sheet is greater than the height of other baffles. Preferably, the height of the baffle near the outlet tube sheet is 0.75-0.85 times the diameter of the tube shell 1, and is 1.2-1.3 times the height of other baffles. By setting the height of the outlet baffle, the liquid can pass through from the upper part as much as possible to flush the steam on the upper part and avoid steam accumulation on the outlet tube sheet. Moreover, the height setting of the baffle is coordinated with the distribution density change of the through hole 10, so that the liquid and steam are fully mixed in the lower part, and the upper steam accumulation is reduced, so that the heat exchange is uniform as a whole, the pressure in the tube shell is reduced, and the purpose of sufficient mixing and heat exchange is further achieved.

[0041] As an improvement, the spacing between the lower baffle plate near the outlet tube sheet and the outlet tube sheet is smaller than the spacing between the lower baffle plate near the outlet tube sheet and the adjacent baffle plates. By reducing the spacing, the liquid flows quickly, flushing the steam gathered on the upper part of the baffle plate and other positions, reducing the upper steam accumulation, making the overall heat exchange uniform, reducing the pressure in the tube shell, and further achieving the purpose of fully mixing and heat exchange.

[0042] As an improvement, the height of the lower baffle is gradually increased from the inlet head 4 to the outlet head 5. This is mainly because as the steam and liquid continue to exchange heat, the steam will be increasingly concentrated in the upper part due to its low density, thereby increasing the pressure in the upper part. As the steam gathers in the upper part, the heat exchange effect deteriorates, so it is necessary to increase the continuous impact of the liquid to disperse and mix the steam. Because the liquid has a high density, it is not easy to impact the upper part. Therefore, by gradually increasing the height of the lower baffle, the flow rate of the liquid flowing to the upper part is increased, so that the impact force becomes greater and greater with the flow direction. Compared with the baffles of the same height, it can not only ensure that the flow resistance is not large, but also achieve full mixing of the vapor and liquid, thereby improving the heat exchange effect.

[0043] As an improvement, the height of the lower baffle gradually increases from the inlet end cap 4 to the outlet end cap 5. Through the above arrangement, the gas-liquid is fully mixed and the heat exchange effect is improved.

[0044] As an improvement, the spacing between adjacent baffles 11 increases continuously from the inlet head 4 to the outlet head 5. As the fluid continues to flow, steam continues to flow out, causing more and more fluid mixed with steam and liquid, which leads to a continuous increase in flow velocity. In particular, due to the presence of steam, a steam-water mixture may exist, which increases the flow velocity during the flow process and increases the noise. By increasing the spacing between adjacent baffles, the flow velocity can be balanced to avoid generating a lot of noise.

[0045] As an improvement, the distance between adjacent baffles 11 increases from the inlet end cap 4 to the outlet end cap 5, which can further ensure the flow velocity balance and reduce the noise.

[0046] Although the present invention has been disclosed as above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A steam heat exchange tube, comprising a tube body and a spiral flow channel sheet arranged outside the tube body, one end of the heat exchange tube is open for steam to flow in, and the other end is closed, a steam outlet hole is arranged on the tube body between the spiral flow channel sheets, and the steam in the heat exchange tube flows out through the steam outlet hole to mix with the external fluid for heat exchange.

2. The heat exchange tube according to claim 1, characterized in that: From one end of the heat exchange tube to the other end, the flow area of ​​the steam outlet hole increases continuously.

3. The heat exchange tube according to claim 2, characterized in that: From one end of the heat exchange tube to the other, the flow area of ​​the steam outlet hole increases continuously and more and more.

4. The heat exchange tube according to claim 1, characterized in that: The spacing between the spiral flow channel sheets and the height of the spiral flow channel sheets are 1:(1.5-2).

5. A steam-water mixing heat exchanger, the heat exchanger comprising a tube shell, a heat exchange tube, a liquid inlet pipe, an inlet head and an outlet head, the liquid inlet pipe is arranged on the tube shell, the inlet head and the outlet head are respectively provided with a steam inlet pipe and a fluid outlet pipe; an inlet tube sheet is arranged between the inlet head and the tube shell, and an outlet tube sheet is arranged between the outlet head and the tube shell, the heat exchange tube is arranged in the tube shell, the first end and the second end of the heat exchange tube are respectively fixedly connected to the inlet tube sheet and the outlet tube sheet, wherein the first end is connected to the inlet head, and the second end is not connected to the outlet head; a steam outlet hole for gas outflow is arranged on the tube wall of the heat exchange tube, and a through hole connecting the tube shell and the outlet head is arranged on the outlet tube sheet, characterized in that The heat exchange tube comprises a tube body and a spiral flow channel sheet arranged outside the tube body. Steam outlet holes are arranged on the tube body between the spiral flow channel sheets, and the steam in the heat exchange tube flows out through the steam outlet holes.

6. The heat exchanger according to claim 5, characterized in that From the inlet head to the outlet head, the flow area of ​​the steam outlet hole increases continuously.

7. The heat exchanger according to claim 6, characterized in that The flow area of ​​the steam outlet hole is increasing more and more.

8. The heat exchanger according to claim 5, characterized in that The steam enters the heat exchange tube through the header from the steam inlet pipe, then comes out through the steam outlet hole of the heat exchange tube, mixes with the liquid entering through the liquid inlet pipe for heat exchange, and the fluid after heat exchange enters the outlet header through the through hole of the outlet tube sheet, and then flows out from the fluid outlet pipe.

9. The heat exchanger according to claim 5, characterized in that The spacing between the spiral flow channel sheets and the height of the spiral flow channel sheets are 1:(1.5-2).

10. The heat exchanger according to claim 5, characterized in that The height of the spiral flow channel sheet is 0.3-0.4 times the outer diameter of the heat exchange tube.

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