Dry and wet integrated falling film evaporation heat exchanger

Abstract

The utility model discloses a dry-wet integrated falling film evaporation heat exchanger which is composed of a high-temperature medium channel, heat pipe bundles with different evaporation temperatures, a partition plate and a low-temperature medium channel. The high-temperature medium channel and the low-temperature medium channel are separated by the partition plate to form independent channels for high-temperature media and low-temperature media, and the heat pipe bundle penetrates through the partition plate and is in sealed connection, so that the high-temperature media and the low-temperature media exchange heat under the complete isolation condition. The heat pipe bundles are sequentially arranged into a high-temperature tube bundle, a medium-temperature tube bundle and a low-temperature tube bundle in the flowing direction of a high-temperature medium, the low-temperature tube bundle, the medium-temperature tube bundle and the high-temperature tube bundle are sequentially arranged in the flowing direction of a low-temperature medium, and a high-low-temperature medium countercurrent flow heat exchange and complete cascade heat transfer model is formed. And the heat pipe bundle partially or completely adopts falling film evaporation heat transfer in the low-temperature medium channel. The heat pipe heat exchanger overcomes the defects that the heat transfer temperature difference of a traditional heat pipe heat exchanger is reduced along the process and the heat transfer coefficient is low, and is particularly suitable for application scenes where heat transfer is isolated and low-temperature media need to be heated and humidified at the same time.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heat pipe heat exchanger, in particular to a dry-wet integrated falling film evaporation heat exchanger. BACKGROUND

[0002] Heat pipe is a kind of high-efficiency phase change heat transfer element, which has been widely used in various application scenarios, especially in liquid-gas, gas-gas and solid-gas heat transfer environments where high and low temperature media need to be fully isolated. The heat pipe is generally a sealed tubular element, filled with phase change material, which absorbs heat by evaporation at the high temperature medium end and releases heat by condensation at the low temperature medium end, completing the heat transfer process. The evaporation temperature of the heat pipe is different due to different phase change materials or different initial pressures in the pipe. Affected by the temperature difference, the heat transfer capacity of the same evaporation temperature heat pipe in different external media is also different, that is, the optimal application temperature of the heat pipe is determined by the evaporation temperature of the internal phase change medium and the external medium temperature.

[0003] The conventional heat pipe heat exchanger generally uses heat pipes with a single evaporation temperature, which shows that the heat transfer temperature difference decreases gradually along the flow direction of the heat transfer medium, and the heat transfer capacity of the heat pipe also decreases gradually, which leads to uneven heat load in each region of the device, causing large thermal expansion stress and affecting the service life of the device. When using economic area arrangement, the high temperature medium discharge temperature is high, and the low temperature medium has limited temperature rise, which leads to low system energy efficiency.

[0004] In the conventional heat pipe heat exchanger, when the heat pipe releases heat to the gas phase medium, dry outer fins are generally used for heat transfer enhancement. This method essentially increases the amount of material in a unit space, that is, increases the contact area between the heat pipe and the gas phase medium in a unit volume, which has limited effect on the heat transfer coefficient, and the overall steel consumption is high.

[0005] Under the background of more and more precise energy utilization, a new type of heat exchanger is needed to make up for the defects of conventional heat pipe heat exchangers. SUMMARY

[0006] To solve the problems of conventional heat pipe heat exchangers, such as decreasing heat transfer capacity along the flow process and low heat transfer coefficient between the heat pipe and the gas phase medium, the present application discloses a dry-wet integrated falling film evaporation heat exchanger, which is particularly suitable for application scenarios that require heat isolation and simultaneous temperature and humidity increase of low temperature medium.

[0007] The dry-wet integrated falling film evaporative heat exchanger comprises a high-temperature medium channel 1, a heat pipe bundle 2, a partition plate 3 and a low-temperature medium channel 4. The high-temperature medium channel 1 and the low-temperature medium channel 4 are separated by the partition plate 3 to form independent medium channels. The high-temperature medium channel 1 is used for flowing of a heat releasing medium, and the low-temperature medium channel 4 is used for flowing of a heat absorbing medium. The heat pipe bundle 2 penetrates through the partition plate 3 and is sealingly connected with the partition plate 3. One end of the heat pipe bundle 2 is located in the high-temperature medium channel 1, and the other end is located in the low-temperature medium channel 4. The heat pipe bundle 2 is a bundle composed of heat pipes with different evaporation temperatures, and the working medium in the heat pipe bundle 2 is a phase change material. The phase change material absorbs heat in the high-temperature medium channel, evaporates into gaseous material, flows in the pipe to the low-temperature medium channel, heats the low-temperature medium, is condensed back to liquid state and flows back to the high-temperature medium channel along the inner wall of the pipe to perform the next evaporation-condensation cycle.

[0008] To solve the problem of temperature difference between the heat pipe and the external working medium, the heat pipe bundle 2 is composed of one, two or three of a high-temperature pipe bundle 21, a medium-temperature pipe bundle 22 and a low-temperature pipe bundle 23. The phase change temperature in the pipe of the high-temperature pipe bundle 21 is 100-500 DEG C, the phase change temperature in the pipe of the medium-temperature pipe bundle 22 is 50-100 DEG C, and the phase change temperature in the pipe of the low-temperature pipe bundle 23 is 5-50 DEG C. The high-temperature pipe bundle 21, the medium-temperature pipe bundle 22 and the low-temperature pipe bundle 23 of the heat pipe bundle 2 are arranged from high to low in evaporation temperature along the direction in which the temperature of the high-temperature medium decreases.

[0009] To solve the problem of low heat transfer coefficient between the heat pipe and the gaseous medium, all or part of the heat pipe bundle 2 in the low-temperature medium channel 4 uses falling film evaporation to heat the low-temperature medium. The falling film evaporation heat transfer coefficient is 3-8 times that of the conventional dry heat transfer coefficient.

[0010] Compared with the prior art, the present application has the following beneficial effects:

[0011] 1. In the same heat exchanger, the high-temperature, medium-temperature and low-temperature heat pipe bundles are sequentially arranged along the direction in which the high-temperature medium flows, i.e. the direction in which the temperature decreases, so as to maintain a stable heat transfer temperature difference in each region of the heat exchanger, to obtain approximately equivalent heat load, to reduce the thermal expansion stress of each region of the heat exchanger and to prolong the service life. The heat transfer temperature difference of the region is greater than that of the conventional heat exchanger, so the overall heat exchange capacity of the heat exchanger can be improved.

[0012] 2. The falling film evaporation is used as a heat transfer enhancement measure between the heat exchanger and the low-temperature gaseous medium, and the heat transfer coefficient is higher than that of the conventional dry heat transfer, so the heat exchange capacity of the heat exchanger can be further improved.

[0013] 3. When the heat pipe bundle 2 adopts partial falling film evaporation, the dry heat exchange part can further increase the low temperature medium temperature and adjust the relative humidity of the low temperature medium, so that the functions of temperature rising, humidifying and relative humidity adjusting can be realized in the same heat exchanger, and the advantages of integrated arrangement and multi-function of one machine of the application are fully embodied. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The dry-wet integrated falling film evaporation heat exchanger.

[0015] Figure 2 The K-K view of Figure 1

[0016] SEQUENCE OF DRAWINGS

[0017] 1 - high temperature medium channel; 11 - high temperature medium inlet; 12 - high temperature medium outlet; 13 - high temperature medium channel shell; 14 - blowdown port.

[0018] 2 - heat pipe bundle; 21 - high temperature pipe bundle; 22 - medium temperature pipe bundle; 23 - low temperature pipe bundle;

[0019] 3 - partition plate;

[0020] 4 - low temperature medium channel; 41 - low temperature medium inlet; 42 - low temperature medium outlet; 43 - low temperature medium channel shell; 431 - first water pool; 432 - second water pool; 44 - drain port; 45 - feed water port; 46 - distribution pump; 47 - connecting pipe system; 48 - first distribution device; 49 - water amount control valve; 410 - falling film pool; 411 - falling film pool shell;

[0021] A - falling film channel; A1 - first kind of falling film channel; A2 - second kind of falling film channel. DETAILED DESCRIPTION

[0022] The application and its embodiments will be described in further detail below with reference to the drawings, and it should be noted that the following description is intended to facilitate the understanding of the application and does not impose any limitation on the application.

[0023] Unless otherwise defined, the professional terms used in the present application have the same meanings as commonly understood by those skilled in the art. The professional terms used in the present application are only used for describing the specific embodiments and are not intended to limit the protection scope of the application.

[0024] The application is described in detail below in combination with the drawings. Figure 1 ​The dry-wet integrated falling film evaporative heat exchanger comprises a high-temperature medium channel 1, a heat pipe bundle 2, a partition plate 3 and a low-temperature medium channel 4. The high-temperature medium channel 1 and the low-temperature medium channel 4 are separated by the partition plate 3 to form independent medium channels. The high-temperature medium channel 1 is used for flowing through a heat releasing medium, and the low-temperature medium channel 4 is used for flowing through a heat absorbing medium. The heat pipe bundle 2 penetrates through the partition plate 3 and is sealingly connected with the partition plate 3. One end of the heat pipe bundle 2 is located in the high-temperature medium channel 1, and the other end is located in the low-temperature medium channel 4, which is a heat transfer unit of the heat releasing medium and the heat absorbing medium. The heat pipe bundle 2 comprises one, two or three of a high-temperature pipe bundle 21, a medium-temperature pipe bundle 22 and a low-temperature pipe bundle 23. The high-temperature pipe bundle 21, the medium-temperature pipe bundle 22 and the low-temperature pipe bundle 23 are filled with phase change materials, the phase change materials have different evaporation phase change temperatures, and the high-temperature pipe bundle 21, the medium-temperature pipe bundle 22 and the low-temperature pipe bundle 23 are sequentially arranged along the high-temperature medium flow direction, i.e. the direction of temperature reduction, and are inversely arranged along the low-temperature medium flow direction according to the evaporation temperatures of the phase change materials in the high-temperature pipe bundle 21, the medium-temperature pipe bundle 22 and the low-temperature pipe bundle 23. Part or all of the heat pipe bundle 2 in the low-temperature medium channel 4 uses a falling film evaporation mode to heat the low-temperature medium.

[0025] The high-temperature medium channel 1 comprises a high-temperature medium inlet 11, a high-temperature medium outlet 12, a high-temperature medium channel shell 13 and a blowdown port 14. The high-temperature medium enters the heat exchanger from the high-temperature medium inlet 11, sequentially washes the high-temperature pipe bundle 21, the medium-temperature pipe bundle 22 and the low-temperature pipe bundle 23 of the heat pipe bundle 2 located in the high-temperature medium channel 1, and then exits the high-temperature medium channel from the high-temperature medium outlet 12 and enters a subsequent system.

[0026] The evaporation phase change temperature in the pipe of the high-temperature pipe bundle 21 is 100-500 DEG C, the evaporation phase change temperature in the pipe of the medium-temperature pipe bundle 22 is 50-100 DEG C, and the evaporation phase change temperature in the pipe of the low-temperature pipe bundle 23 is 5-50 DEG C. That is, the heat pipe bundle 2 is arranged in the high-temperature medium channel 1 from high to low according to the phase change temperature, the arrangement order is consistent with the temperature reduction order of the high-temperature medium, and therefore a relatively stable heat transfer temperature difference between the high-temperature medium and the heat pipe bundle 2 can be maintained.

[0027] The high-temperature medium is a heat releasing medium of the heat exchanger, and the heat releasing medium is flue gas, air, water vapor, water, fuel gas, oil or quicksand with a temperature higher than that of the low-temperature medium.

[0028] The low-temperature medium passage 4 is composed of a low-temperature medium inlet 41, a low-temperature medium outlet 42, a low-temperature medium passage shell 43, a first water pool 431, a second water pool 432, a water outlet 44, a water inlet 45, a spray pump 46, a connecting pipeline 47, a first spray device 48, a water volume control valve 49, a falling film pool 410, and a falling film pool shell 411. The low-temperature medium enters the heat exchanger from the low-temperature medium inlet 41, sequentially flushes the low-temperature tube bundle 23, the medium-temperature tube bundle 22, and the high-temperature tube bundle 21 of the heat pipe tube bundle 2, and then exits the low-temperature medium passage from the low-temperature medium outlet 42 and enters the subsequent system.

[0029] The low-temperature medium is a heat-absorbing medium of the heat exchanger, and the heat-absorbing medium is flue gas, air, or gas with a temperature lower than that of the heat-releasing medium.

[0030] The low-temperature medium and the high-temperature medium are arranged in countercurrent, and the low-temperature medium and the heat pipe tube bundle 2 are arranged in stepwise downstream, so that a relatively stable temperature difference higher than that of a conventional heat exchanger is maintained between the low-temperature medium and the high-temperature medium, between the low-temperature medium and the heat pipe tube bundle 2, and between the heat pipe tube bundle 2 and the high-temperature medium, thereby achieving the goal of increasing the heat exchange capacity of the heat exchanger.

[0031] The heat pipe tube bundle 2 and the low-temperature medium are arranged in all or part of the regions in a falling film evaporation method for heat transfer strengthening. The falling film evaporation is preferably arranged at the top of the medium-temperature tube bundle 22 and the low-temperature tube bundle 23. The falling film mode at the top of the low-temperature tube bundle 23 is preferably a large-water-volume spray, which is arranged at the top of the low-temperature tube bundle 23 to quickly increase the temperature and humidity of the low-temperature medium. A part of the spray water is sprayed on the outer surface of the low-temperature tube bundle 23 to form a water film, which evaporates under the heating of the working medium in the low-temperature tube bundle 23 to transfer heat to the low-temperature medium, thereby increasing the temperature of the low-temperature medium and its ability to carry gaseous water. The falling film mode at the top of the medium-temperature tube bundle 22 is preferably a controlled-water spray, which is arranged in a film-like spray structure and flows downward along the outer wall of the medium-temperature tube bundle 22 to form a water film, which evaporates under the heating of the working medium in the medium-temperature tube bundle 22 to transfer heat to the low-temperature medium. Since the water volume is controllable, the spray temperature of the medium-temperature tube bundle 22 is also controllable. The controlled-water spray is completed by the water volume control valve 49 and the falling film pool 410. The water volume control valve 49 adjusts and controls the water volume entering the falling film pool 410, and the stored water in the falling film pool 410 forms a water film on the outer wall of the medium-temperature tube bundle 22 through the falling film passage A.

[0032] The large-water-volume spray and the controlled-water spray can be arranged at the top of the high-temperature tube bundle 21, the medium-temperature tube bundle 22, and the low-temperature tube bundle 23, and the specific arrangement mode is determined according to the temperature and humidity requirements of the low-temperature medium.

[0033] The falling film evaporation water source is from the water storage pool at the bottom of the low-temperature medium channel 4. The water storage pool is arranged as one, two or three, respectively storing the remaining water of the corresponding falling film evaporation area, one, two or three of the water pools are provided with one or both of the water inlet 45 and the water outlet 44, and one, two or three of the water pools are provided with the water distribution pump 46, which provides the falling film evaporation with the water source through the connecting pipeline 47.

[0034] Preferably, the high-temperature tube bundle 21 adopts dry heat exchange with the low-temperature medium, and the temperature of the low-temperature medium is raised through the dry heat exchange, so as to adjust the relative humidity of the low-temperature medium at the low-temperature medium outlet 42, so as to meet the control requirements of the system on the dewing of the low-temperature medium in the subsequent section. The high-temperature tube bundle 21 of the dry heat exchange adopts a fin structure as a heat transfer enhancement measure.

[0035] In combination with Figure 2 : The heat pipe tube bundle 2 adopting the falling film pool water distribution and control passes through the falling film pool shell 411, and a gap is left between the pipe penetrating position and the falling film pool shell 411 as a falling film channel A. The falling film channel A is a continuous gap, referred to as a first falling film channel A1, or an intermittent gap, referred to as a second falling film channel A2.

[0036] In combination with Figure 1 and Figure 2 : The heat pipe tube bundle 2 adopting the falling film pool water distribution and control has a part inserted into the inside of the falling film pool 410 at the top, and the heat inside the heat pipe tube bundle 2 is used to heat the stored water in the falling film pool.

[0037] The above is only an application example of the present application, and does not limit the protection scope of the present application. Any equivalent structure made by using the content of the specification and the drawings, or directly or indirectly used in the related technical field is also included in the patent protection scope of the present application.

Claims

1. A falling film evaporator heat exchanger integrated with wetting and drying, which is composed of a high-temperature medium channel (1), a heat pipe bundle (2), a partition plate (3), and a low-temperature medium channel (4), characterized in that: The high-temperature medium passage (1) and the low-temperature medium passage (4) are separated by the partition plate (3) to form independent medium passages, the high-temperature medium passage (1) is used for flowing through the heat releasing medium, and the low-temperature medium passage (4) is used for flowing through the heat absorbing medium; the heat pipe bundle (2) penetrates through the partition plate (3), the heat pipe bundle (2) is in sealing connection with the partition plate (3); one end of the heat pipe bundle (2) is located in the high-temperature medium passage (1), and the other end is located in the low-temperature medium passage (4), and the heat pipe bundle (2) is a heat transfer unit of the heat releasing medium and the heat absorbing medium; the heat pipe bundle (2) is composed of heat pipes with different evaporation temperatures, the heat pipes are filled with phase change materials, the heat pipe bundle (2) is composed of one, two or three of high-temperature pipe bundles, medium-temperature pipe bundles and low-temperature pipe bundles, and part or all of the heat pipe bundle (2) in the low-temperature medium passage (4) adopts a falling film evaporation mode to heat the low-temperature medium.

2. The falling film evaporative heat exchanger of claim 1, wherein: The low-temperature medium passage (4) is provided with a water pool at the bottom, the water pool is divided into one, two or three, and the water pool is used for storing residual water corresponding to the falling film evaporation area, one, two or three of the water pools are provided with one or two of a water inlet and a water outlet, and one, two or three of the water pools are provided with a spray pump to provide a water source for the falling film evaporation.

3. The falling film evaporative heat exchanger of claim 1, wherein: The low-temperature medium passage (4) is provided with a falling film pool or a spray device at the top of the heat pipe bundle (2) which adopts the falling film evaporation mode to heat the low-temperature medium; the top of the heat pipe bundle (2) is immersed in the falling film pool or the lower part of the spray device.

4. The falling film evaporative heat exchanger of claim 3, wherein: The heat pipe bundle (2) and the shell of the falling film pool are provided with a falling film passage, and the falling film passage is a continuous or intermittent gap.

5. The falling film evaporative heat exchanger of claim 1, wherein: The heat releasing medium is flue gas, air, water vapor, water, fuel gas or oil, or flowing sand, which has a higher temperature than the heat absorbing medium.

6. The falling film evaporative heat exchanger of claim 1, wherein: The heat absorbing medium is flue gas, air or fuel gas, which has a lower temperature than the heat releasing medium.

7. The falling film evaporative heat exchanger of claim 1, wherein: The heat pipe bundle (2) is sequentially provided with one, two or three of high-temperature pipe bundles, medium-temperature pipe bundles and low-temperature pipe bundles along the temperature decreasing direction of the heat releasing medium.

8. The falling film evaporator of claim 1, wherein: The heat pipe bundle (2) is filled with phase change materials, and the high-temperature medium heat is transferred to the low-temperature medium in a phase change mode, the phase change temperature in the pipe of the high-temperature pipe bundle is 100-500 DEG C, the phase change temperature in the pipe of the medium-temperature pipe bundle is 50-100 DEG C, and the phase change temperature in the pipe of the low-temperature pipe bundle is 5-50 DEG C.

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