A cooling recovery system and a method for preparing cooling liquid

Abstract

The present invention provides a cold recovery system and a method for preparing a coolant, the system comprising: a cold source supply device; a heat exchange device, the heat exchange device comprising a heat exchange tank connected to the cold source supply device and a heat exchange tube arranged in the heat exchange tank, the heat exchange tank stores a coolant, and the heat exchange tube forms an independent flow channel in the coolant; a to-be-cooled liquid supply device, the to-be-cooled liquid supply device is connected to the inlet of the heat exchange tube, and is used to provide the to-be-cooled liquid to the heat exchange tube. According to the cold recovery system and the method for preparing a coolant of the present invention, the coolant can be prepared by utilizing the cold of the recovered cold source, while improving the cold recovery efficiency of the cold source and making full use of the recovered cold, avoiding the waste of cold caused by direct heat exchange between the cold source and the air, and saving the cost of factory operation.

Description

Technical Field

[0001] The invention relates to the field of cold recovery processing, and in particular to a cold recovery system and a method for preparing a cooling liquid. Background Art

[0002] The recycling and reuse of cold source cold is widely used in industrial production. For example, waste incineration plants and hazardous waste treatment plants usually need a large amount of nitrogen, and waste incineration plants and hazardous waste treatment plants generally purchase liquid nitrogen from outside and then vaporize the purchased liquid nitrogen on site through a liquid nitrogen vaporizer to obtain the required nitrogen. During the vaporization process of liquid nitrogen, a large amount of cold energy is directly discharged into the air, which is not fully utilized. In addition, when liquid nitrogen is vaporized by the vaporizer, it exchanges heat with the air, and the heat transfer coefficient of air is very small, which is not conducive to heat exchange.

[0003] At the same time, waste incineration plants and hazardous waste treatment plants require chilled water during their operations. Usually, waste incineration plants and hazardous waste treatment plants will purchase refrigerators to prepare the chilled water required for the operation process. The use of refrigerators to prepare chilled water consumes a lot of electricity.

[0004] To this end, the present invention provides a cooling recovery system and a method for preparing cooling liquid to solve the problems in the prior art. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] The present invention provides a cold recovery system, the system comprising:

[0007] Cold source supply device;

[0008] A heat exchange device, the heat exchange device comprising a heat exchange tank connected to the cold source supply device and a heat exchange tube arranged in the heat exchange tank, a coolant is stored in the heat exchange tank, and the heat exchange tube forms an independent flow channel in the coolant;

[0009] A device for supplying liquid to be cooled is connected to the inlet of the heat exchange tube and is used for supplying liquid to be cooled to the heat exchange tube.

[0010] A coolant storage device is connected to the outlet of the heat exchange tube.

[0011] Exemplarily, the cold source is liquid nitrogen, the liquid to be cooled is chilled water, and the cooling liquid is chilled water.

[0012] Exemplarily, the heat exchange device further includes a heat exchanger connected between the liquid to be cooled supply device and the heat exchange tube, wherein the refrigerant is passed into the heat exchanger to perform primary heat exchange with the liquid to be cooled to form a primary cooling liquid.

[0013] Exemplarily, the heat exchanger is a tubular heat exchanger, the shell side inlet of the tubular heat exchanger is connected to the cooling liquid supply device, the shell side outlet of the tubular heat exchanger outputs the primary cooling liquid to the heat exchange tubes, the tube side inlet of the tubular heat exchanger inputs the coolant in the heat exchange tank into the tubular heat exchanger, and the tube side outlet of the tubular heat exchanger outputs the coolant from the tubular heat exchanger to the heat exchange tank.

[0014] Exemplarily, the coolant is ethylene glycol.

[0015] Exemplarily, the cold source supply device also includes a liquid nitrogen spray gun disposed at the bottom of the heat exchange tank and connected to the cold source supply device.

[0016] Exemplarily, the liquid nitrogen spray gun includes a regulating device for regulating the amount of liquid nitrogen sprayed into the coolant by the liquid nitrogen spray gun.

[0017] Exemplarily, a first cryogenic pump is provided between the tube inlet and the heat exchange tank.

[0018] Exemplarily, a second cryogenic pump is provided between the outlet of the heat exchange tube and the coolant storage device.

[0019] Exemplarily, the system further comprises a nitrogen recovery device connected to the heat exchange tank, for recovering nitrogen after vaporization of the liquid nitrogen.

[0020] The present invention also provides a method for preparing a cooling liquid, comprising:

[0021] Mixing the cold source with the coolant to reduce the temperature of the coolant;

[0022] The liquid to be cooled is heat exchanged with the coolant to form a cooling liquid.

[0023] Exemplarily, the cold source is liquid nitrogen, the liquid to be cooled is chilled water, and the cooling liquid is chilled water.

[0024] Exemplarily, the step of mixing the cold source with the coolant includes spraying the liquid nitrogen into the coolant.

[0025] Exemplarily, in the step of spraying the liquid nitrogen into the coolant, the amount of the liquid nitrogen sprayed into the coolant is adjusted.

[0026] Exemplarily, the step of exchanging heat between the liquid to be cooled and the coolant includes a first heat exchange step of providing a channel in the coolant during the mixing of the cold source and the coolant, and passing the liquid to be cooled through the channel.

[0027] Exemplarily, the step of exchanging heat between the liquid to be cooled and the coolant further comprises a second heat exchange step of exchanging heat between the liquid to be cooled and the coolant in a heat exchanger before the first heat exchange step.

[0028] Exemplarily, before performing the step of exchanging heat between the chilled water and the coolant, the coolant is passed into the heat exchanger for pre-heat exchange, so that the heat exchanger is in a low-temperature environment.

[0029] Exemplarily, when the temperature of the refrigerant is between -8°C and 0°C, the refrigerant is passed into the heat exchanger for pre-heat exchange.

[0030] Exemplarily, the step of exchanging heat between the chilled water and the coolant is performed when the temperature of the coolant is between -8°C and 5°C.

[0031] Exemplarily, the method further comprises the step of recovering nitrogen.

[0032] According to the cold source cold energy recovery system and the method for preparing coolant of the present invention, the cold energy of the cold source recovered by directly mixing the cold source with the refrigerant can, on the one hand, avoid the waste of cold energy caused by direct heat exchange between the cold source and the air, and on the other hand, the recovered cold energy can be used to prepare the coolant, replacing the refrigerator to prepare the coolant, saving electric energy, thereby saving the cost of factory operation. At the same time, according to the cold source cold energy recovery system and the method for preparing coolant of the present invention, the cold energy is recovered and reused by directly mixing the cold source with the refrigerant, the cold energy recovery utilization rate is high, the recovery speed is fast, and the dual functions of cold source cold energy recovery and coolant preparation are realized at the same time, the equipment is compact, and the investment and operation costs are low. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following drawings of the present invention are used to understand the present invention as part of the present invention. The embodiments of the present invention are shown in the drawings and the description thereof is used to explain the principle of the present invention.

[0034] In the attached figure:

[0035] Figure 1 A schematic structural diagram of a cold recovery system according to an embodiment of the present invention;

[0036] Figure 2 The present invention is a flowchart of a method for preparing a cooling liquid according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0038] In order to fully understand the present invention, a detailed description will be provided in the following description to illustrate a cold recovery system and a method for preparing a coolant according to the present invention. Obviously, the implementation of the present invention is not limited to the specific details familiar to those skilled in the art of biomass incineration flue gas treatment. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0040] Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of layers and regions is exaggerated, and the same reference numerals are used to represent the same elements, and thus their description will be omitted.

[0041] The following is an illustrative description of the cold recovery system and the coolant preparation method of the present invention using the liquid nitrogen cold recovery system and the chilled water preparation process involved in waste incineration treatment. It should be understood that the embodiment uses the waste incineration system involving the liquid nitrogen cold recovery system and the chilled water preparation process as an example for description and is not intended to limit the present invention. Any system involving the need to recover cold and the process of preparing cooling are applicable to the present invention.

[0042] Waste incineration plants and hazardous waste treatment plants usually require a large amount of nitrogen, and waste incineration plants and hazardous waste treatment plants generally purchase liquid nitrogen from outside and then vaporize the purchased liquid nitrogen on site through a liquid nitrogen vaporizer to obtain the required nitrogen. During the vaporization process of liquid nitrogen, a large amount of cold energy is directly discharged into the air, which is not fully utilized. In addition, liquid nitrogen exchanges heat with the air when it is vaporized by the vaporizer, and the heat transfer coefficient of air is very small, which is not conducive to heat exchange. At the same time, waste incineration plants and hazardous waste treatment plants require chilled water during operation. Usually, waste incineration plants and hazardous waste treatment plants will purchase refrigerators to prepare the chilled water required for the operation process. The use of refrigerators to prepare chilled water consumes a lot of electricity.

[0043] To this end, the present invention provides a cold recovery system, the system comprising:

[0044] Cold source supply device;

[0045] A heat exchange device, the heat exchange device comprising a heat exchange tank connected to the cold source supply device and a heat exchange tube arranged in the heat exchange tank, a coolant is stored in the heat exchange tank, and the heat exchange tube forms an independent flow channel in the coolant;

[0046] A device for supplying liquid to be cooled is connected to the inlet of the heat exchange tube and is used for supplying liquid to be cooled to the heat exchange tube.

[0047] A coolant storage device is connected to the outlet of the heat exchange tube.

[0048] According to the cold source cold energy recovery system and the method for preparing coolant of the present invention, the cold energy of the cold source recovered by directly mixing the cold source with the refrigerant can, on the one hand, avoid the waste of cold energy caused by direct heat exchange between the cold source and the air, and on the other hand, the recovered cold energy can be used to prepare the coolant, replacing the refrigerator to prepare the coolant, saving electric energy, thereby saving the cost of factory operation. At the same time, according to the cold source cold energy recovery system and the method for preparing coolant of the present invention, the cold energy is recovered and reused by directly mixing the cold source with the refrigerant, the cold energy recovery utilization rate is high, the recovery speed is fast, and the dual functions of cold source cold energy recovery and coolant preparation are realized at the same time, the equipment is compact, and the investment and operation costs are low.

[0049] Embodiment 1

[0050] Reference below Figure 1 The cold recovery system of the present invention is exemplified, wherein Figure 1 Schematic diagram of the structure of a cold recovery system according to an embodiment of the present invention.

[0051] like Figure 1As shown, the cold recovery system includes a cold source supply device. In the waste incineration treatment industry with liquid nitrogen as a cold source, the cold source supply device is set to a liquid nitrogen supply device composed of a liquid nitrogen transport vehicle 1, a self-pressurized liquid nitrogen tank 2, a first stop valve 3 and a second stop valve 4. Wherein, the first stop valve is arranged between the upper opening and the lower opening of the self-pressurized liquid nitrogen tank 2 to adjust the pressure of the self-pressurized liquid nitrogen tank, and the second stop valve is arranged between the lower opening of the self-pressurized liquid nitrogen tank 2 and the heat exchange tank to control the outflow of the liquid in the self-pressurized liquid nitrogen tank. It should be understood that the present embodiment uses the combination of a liquid nitrogen transport vehicle, a self-pressurized liquid nitrogen tank, a first stop valve and a second stop valve as an example to illustrate the setting of the liquid nitrogen supply device, which is only exemplary, and any device that can provide liquid nitrogen is applicable to the present invention; at the same time, it should be understood that the present embodiment uses liquid nitrogen as a cold source as an example to illustrate only exemplary, and any cold source that is low temperature and can provide cold for exchange is applicable to the present invention.

[0052] Continue to view Figure 1 , the cold recovery system also includes a heat exchange device, wherein the heat exchange device includes a heat exchange tank 11 and a heat exchange tube 5 located in the heat exchange tank 11, the heat exchange tank 11 is connected to the self-pressurized liquid nitrogen tank 2 of the liquid nitrogen supply device, a refrigerant is stored in the heat exchange tank, and the heat exchange tube 5 forms an independent flow channel in the refrigerant. Exemplarily, the refrigerant can be any organic solution with a low freezing point, such as ethylene glycol, trichloroethylene, etc. Exemplarily, the refrigerant is ethylene glycol. The heat exchange tank is connected to the liquid nitrogen supply device, that is, the liquid nitrogen provided by the liquid nitrogen supply device is directly introduced into the refrigerant, so that the refrigerant and the liquid nitrogen undergo direct heat exchange, and at the same time, all the liquid nitrogen is vaporized in the refrigerant, and sufficient heat exchange occurs, so that the cold recovery rate of the liquid nitrogen vaporization process is high and the recovery speed is fast.

[0053] Exemplarily, the heat exchange tube is a spirally arranged heat exchange coil. Figure 1 As shown, the heat exchange tube 5 is configured as a heat exchange coil that spirally rises from the bottom to the top of the heat exchange tank 11. The heat exchange tube is configured as a spirally arranged heat exchange coil, which can increase the stroke of the chilled water in the heat exchange tube and increase the time for heat exchange between the chilled water and the refrigerant, so that the chilled water can be fully cooled to fully utilize the cold capacity recovered by the liquid nitrogen.

[0054] Exemplarily, the liquid nitrogen supply device further comprises a liquid nitrogen spray gun disposed at the bottom of the heat exchange tank and connected to the liquid nitrogen supply device. Figure 1As described, a liquid nitrogen spray gun 6 is provided at the bottom of the heat exchange tank 11, and the liquid nitrogen spray gun can be any form of device for spraying liquid nitrogen into the refrigerant, exemplarily, such as a nozzle. Liquid nitrogen enters the refrigerant through the spray gun. Since the temperature of the refrigerant is higher than the boiling point of liquid nitrogen -196°C, the liquid nitrogen naturally vaporizes into nitrogen gas after entering the refrigerant and overflows from the top of the heat exchange tube. The liquid nitrogen is sprayed into the refrigerant in the form of a spray gun. The liquid nitrogen provides an impact in the process of entering the refrigerant, which can further enhance the mixing of liquid nitrogen and the refrigerant, so that the refrigerant and the liquid nitrogen can fully exchange heat, and the coldness of the liquid nitrogen can be fully recovered, so that the recovery rate of the liquid nitrogen coldness is high and the recovery speed is fast.

[0055] Exemplarily, the liquid nitrogen spray gun includes a regulating device capable of regulating the amount of liquid nitrogen sprayed into the coolant by the liquid nitrogen spray gun. By regulating the amount of liquid nitrogen sprayed into the coolant by the liquid nitrogen spray gun through the regulating device, the cooling speed and cooling temperature of the coolant can be controlled, thereby controlling the speed at which the chilled water is cooled into the chilled water, and preventing the chilled water from solidifying during the cooling process or failing to reach a predetermined cooling temperature due to the coolant temperature being too low or too high.

[0056] The cold recovery system also includes a device for supplying liquid to be cooled, which is connected to the inlet of the heat exchange tube to provide the liquid to be cooled to the heat exchange tube. In this embodiment, chilled water preparation is designed in the waste incineration process, and for this purpose, the incoming chilled water is set as the liquid to be cooled, the prepared chilled water is the cooling liquid, and the device for supplying water to be cooled is set as the incoming chilled water supply device. It should be understood that this embodiment uses the incoming chilled water and the preparation of chilled water by the incoming chilled water through heat exchange as an example to illustrate the setting of the liquid to be cooled and the preparation of the cooling liquid by the liquid to be cooled through heat exchange in the cold recovery system. It is only exemplary, and any liquid that needs to be cooled is suitable for the present invention.

[0057] Continue to view Figure 1 , Chilled water supply device ( Figure 1The heat exchanger 5 is not shown in the figure. The chilled water is provided to the heat exchanger through the inlet 501 of the heat exchange tube 5, and is output from the outlet 502 of the heat exchange tube 5. In the heat exchange device, liquid nitrogen is provided to the heat exchange device through the liquid nitrogen supply device, and the liquid nitrogen is vaporized into nitrogen in the heat exchange tank, while reducing the temperature of the refrigerant in the heat exchange tank. The chilled water is cooled in the independent flow channel formed by the heat exchange tube 5 in the refrigerant to form chilled water, so that the liquid nitrogen cold can be recovered, and the recovered liquid nitrogen cold can be used to prepare chilled water. On the one hand, the waste of cold caused by direct heat exchange between liquid nitrogen and air can be avoided. On the other hand, the recovered cold is used to prepare chilled water, replacing the refrigerator to prepare chilled water, saving electric energy, thereby saving the cost of factory operation. According to the liquid nitrogen cold recovery system and the method for preparing chilled water of the present invention, the cold utilization rate is high, the recovery speed is fast, and the dual functions of liquid nitrogen cold recovery and chilled water preparation are realized at the same time. The equipment is compact and the investment and operation costs are low.

[0058] Continue to view Figure 1 The chilled water prepared by the heat exchange device is output to the chilled water storage device 9 through the outlet 502 of the heat exchange pipe 5. The chilled water storage device can be a container or a device that directly uses chilled water. Those skilled in the art can select and use it according to actual needs.

[0059] Exemplarily, the heat exchange device also includes a heat exchanger connected between the chilled water supply device and the heat exchange tube, wherein the cold fluid in the heat exchanger is provided by the refrigerant, and the heat exchanger performs primary heat exchange on the chilled water to form primary chilled water. The chilled water is passed through the heat exchanger to perform primary freezing to form primary chilled water, and then enters the heat exchange tank to finally prepare chilled water. The preparation process of chilled water is divided into steps and performed multiple times to form fully frozen chilled water, thereby avoiding the situation that the chilled water formed by only passing through the heat exchange tank is not fully frozen and the temperature does not meet the requirements. At the same time, since the cold fluid in the heat exchanger is still provided by the refrigerant that recovers the cold of liquid nitrogen, the cold recovered by liquid nitrogen is further fully utilized, thereby improving the utilization rate of the recovered liquid nitrogen cold.

[0060] Exemplarily, the heat exchanger includes a first input port connected to the chilled water supply device, and a first output port for outputting the primary chilled water, wherein the first output port is connected to the inlet of the heat exchange tube. Figure 1 The heat exchange device further includes a heat exchanger 8 connected between the chilled water supply device and the heat exchange tank 11. The heat exchanger 8 includes a first input port 801 connected to the chilled water supply device (not shown) for inputting the chilled water, and a first output port 802 connected to the heat exchange pipe 5. The primary chilled water formed after the chilled water passes through the heat exchanger 8 for primary freezing is input through the heat exchange pipe 5, and is output from the heat exchange pipe 5 to the chilled water storage device 9, thereby completing the freezing of the chilled water.

[0061] Exemplarily, the heat exchanger further comprises a second input port and a second output port respectively connected to both ends of the heat exchange tank, wherein the second input port inputs the coolant in the heat exchange tank into the heat exchanger, and the second output port outputs the coolant from the heat exchanger to the heat exchange tank. Figure 1 The heat exchanger 8 also includes a second input port 803 and a second output port 804 respectively connected to the two ends of the heat exchange tank 11, wherein the second input port 803 inputs the brine in the heat exchange tank 11 into the heat exchanger 8, and the second output port 804 outputs the brine from the heat exchanger 8 to the heat exchange tank 11. Such a configuration allows the brine to form a circulation channel between the heat exchange tank and the heat exchanger, so that the primary refrigeration of the chilled water by the heat exchanger is also obtained through the exchange of cold with the brine, and the liquid nitrogen cold recovered by the brine is further utilized to improve the utilization rate of the recovered cold, while also reducing the use of other brine, further reducing costs.

[0062] Exemplarily, the heat exchanger is a tubular heat exchanger, the first input port is a shell side inlet, the first output port is a shell side outlet, the second input port is a tube side inlet, and the second output port is a tube side outlet. It should be understood that the heat exchanger can be set as any form of heat exchanger, such as an immersion type, a spray type, a plate type heat exchanger, etc. The use of a tubular heat exchanger in this embodiment can increase the turbulence effect and improve the heat exchange efficiency.

[0063] Exemplarily, a first cryogenic pump is provided between the second input port and the heat exchange tank. Figure 1 A first cryogenic pump 7 is provided between the second input port 803 of the heat exchanger 8 and the heat exchange tank 11. The cryogenic pump provided between the second input port and the heat exchange tank can ensure smooth circulation of the coolant between the heat exchanger and the heat exchange tank.

[0064] Exemplarily, a second cryogenic pump is provided between the chilled water storage device and the heat exchange tube. Figure 1 A second cryogenic pump 10 is provided between the chilled water storage device 9 and the outlet 502 of the heat exchange tube 5. The first cryogenic pump is used to pump the chilled water to the chilled water storage device, forming a circulation channel for the chilled water from the chilled water supply device through the heat exchange device to the chilled water storage device, thereby avoiding possible blockage of the chilled water during the circulation process.

[0065] Exemplarily, the outside of the tubular heat exchanger and / or the inside of the heat exchange tank are lined with polytetrafluoroethylene coating. The outside of the tubular heat exchanger is lined with polytetrafluoroethylene coating, thereby effectively avoiding corrosion of the heat exchanger due to temperature changes. Similarly, the inside of the heat exchange tank is lined with polytetrafluoroethylene coating, which also avoids corrosion caused by temperature changes during the circulation process.

[0066] Exemplarily, the system further comprises a nitrogen recovery device connected to the heat exchange tank, for recovering nitrogen gas after the liquid nitrogen is vaporized. The nitrogen recovery device comprises: a gas storage tank, a compressor, and / or a filter. Figure 1 , the nitrogen recovery device includes a filter 12 connected to the heat exchange tank, a compressor 13, and an air tank 14. The filter 12 is used to remove impurities in the nitrogen, such as the vaporized gas of the refrigerant and / or the air. The compressor 13 compresses the nitrogen filtered by the filter and stores it in the air tank 14. The nitrogen in the air tank can be further used for industrial applications, such as waste incineration. At the same time, it should be understood that the present embodiment uses the air tank, the compressor and the filter as examples to illustrate the setting of the nitrogen recovery device is merely exemplary, and any equipment that can utilize or store nitrogen is applicable to the present invention.

[0067] At this point, the exemplary introduction to the cold recovery system of the present invention is completed. It should be understood that the arrangement structure of the cold recovery system shown in this embodiment is not intended to limit the present invention. Any liquid nitrogen cold recovery system provided with a liquid nitrogen supply device, a heat exchange device, a chilled water supply device and a chilled water storage device is applicable to the present invention.

[0068] Embodiment 2

[0069] The present invention also provides a method for preparing a cooling liquid, which utilizes the recovered liquid nitrogen cooling capacity to prepare chilled water. Figure 2 The method of the present invention is exemplified.

[0070] First, see Figure 2 , perform step S1: mix the cold source with the coolant to reduce the temperature of the coolant. This step can be performed in any device that can mix the cold source with the coolant, and the cold source can be any cold source with low temperature and can provide cold for exchange. Exemplarily, the cold source is liquid nitrogen. The coolant can be any organic solution with a low freezing point, such as ethylene glycol, trichloroethylene, etc. Exemplarily, the coolant is ethylene glycol.

[0071] Exemplarily, liquid nitrogen is sprayed into the coolant to mix the liquid nitrogen with the coolant. The liquid nitrogen is sprayed into the coolant in the form of a spray gun to provide impact when the liquid nitrogen enters the coolant, which can further enhance the mixing of the liquid nitrogen and the coolant, so that the coolant and the liquid nitrogen can fully exchange heat, and the coldness of the liquid nitrogen can be fully recovered, so that the recovery rate of the coldness of the liquid nitrogen is high and the recovery speed is fast.

[0072] Further, illustratively, in the step of spraying the liquid nitrogen into the coolant, the amount of the liquid nitrogen sprayed into the coolant is adjusted. By adjusting the amount of liquid nitrogen sprayed into the coolant, the cooling speed and cooling temperature of the coolant can be controlled, so that the chilled water is cooled at an appropriate rate, and the chilled water is prevented from solidifying during the cooling process or failing to reach a predetermined cooling temperature due to the coolant temperature being too low or too high.

[0073] Next, continue to see Figure 2 , execute step S2: exchange heat between the liquid to be cooled and the coolant to form a coolant. The liquid to be cooled can be any liquid that needs to be cooled. Exemplarily, the liquid to be cooled is chilled water, and the chilled water is high-temperature water after heat exchange in the waste incineration process. Exemplarily, the temperature of the chilled water is 2 to 80°C. This temperature is the common temperature of the chilled water formed in the process of waste incineration. It should be understood that the setting of the temperature of the chilled water to 2 to 80°C in this embodiment is not intended to limit the scope of the present invention, and any chilled water that can circulate is applicable to the present invention. At the same time, it should be understood that the setting of the liquid to be cooled using chilled water as an example in this embodiment is only exemplary, and any liquid that needs to be cooled is applicable to the present invention.

[0074] Exemplarily, the step of exchanging heat between the chilled water and the coolant includes a first heat exchange step performed in a channel provided in the coolant during the mixing of the liquid nitrogen and the coolant. The chilled water is directly heat exchanged through a channel provided in the coolant during the mixing of the liquid nitrogen and the coolant, and the step of exchanging heat between the chilled water and the coolant is performed while the coolant recovers the cold of the liquid nitrogen, thereby reducing the time difference between the energy exchange between the coolant and the liquid nitrogen and the energy exchange between the coolant and the chilled water, improving the efficiency of transferring cold between the liquid nitrogen, the coolant and the chilled water, and improving the recovery efficiency and utilization rate of cold. It should be understood that, in this embodiment, the step of exchanging heat between the chilled water and the refrigerant is illustrated by taking the first heat exchange step performed in the channel provided in the refrigerant during the mixing of the liquid nitrogen with the refrigerant as an example, and any form of heat exchange between the chilled water and the refrigerant, such as a heat exchange step performed in a heat exchange tube using the refrigerant after heat exchange with liquid nitrogen as a cold fluid, is applicable to the present invention.

[0075] Exemplarily, the channel includes a spirally arranged coil channel. The channel includes a spirally arranged coil channel, which can increase the distance of the chilled water in the pipeline and increase the heat exchange time between the chilled water and the coolant, so that the chilled water is fully cooled to fully utilize the cold capacity recovered by the liquid nitrogen.

[0076] Exemplarily, the step of exchanging heat between the incoming chilled water and the brine further includes a second heat exchange step performed in a heat exchanger using the brine as a cold fluid. Performing a multi-step heat exchange between the incoming chilled water and the brine can increase the heat exchange between the incoming chilled water and the brine, so that the chilled water is fully cooled.

[0077] Exemplarily, the heat exchanger is a tubular heat exchanger, wherein the chilled water is passed through the shell side of the tubular heat exchanger and the secondary coolant is passed through the tube side of the tubular heat exchanger to perform the second heat exchange step. The use of a tubular heat exchanger can increase the turbulence effect and improve the heat exchange efficiency.

[0078] Exemplarily, the second heat exchange step is performed before the first heat exchange step. Thus, the step of exchanging heat between the incoming chilled water and the secondary coolant includes the second heat exchange step and the second heat exchange step performed sequentially, while improving the efficiency of cold recovery, circulating the secondary coolant between the first heat exchange step and the second heat exchange step, the second heat exchange step performs primary heat exchange on the incoming chilled water to form primary freezing, and the first heat exchange step further performs heat exchange on the incoming chilled water to form final chilled water, thereby improving the freezing effect of the chilled water.

[0079] Exemplarily, before the step of exchanging heat between the incoming chilled water and the brine, the brine is passed through the heat exchanger for pre-heat exchange, so that the heat exchanger is in a low temperature environment. Exemplarily, when the temperature of the brine is -8°C to 0°C, the brine is passed through the heat exchanger for pre-heat exchange. Exemplarily, when the temperature of the brine is -8°C to 5°C, the step of exchanging heat between the incoming chilled water and the brine is performed.

[0080] Exemplarily, the method further comprises a step of recovering nitrogen in the heat exchanging step. The step of recovering nitrogen is performed simultaneously with the step of mixing liquid nitrogen with a coolant and the step of exchanging heat between chilled water and the coolant. The recovered liquid nitrogen can be further used in industrial applications, such as waste incineration. Exemplarily, the step of recovering nitrogen comprises: filtering the vaporized nitrogen, compressing and storing the filtered nitrogen.

[0081] Exemplarily, the temperature of the chilled water is 2-80° C. This temperature is a common temperature of the chilled water formed in the process of waste incineration. It should be understood that the setting of the temperature of the chilled water to 2-80° C. in this embodiment is not intended to limit the scope of the present invention, and any chilled water that can flow is applicable to the present invention.

[0082] See below Figure 1The receiving of a cold recovery system in the illustrated embodiment 1 describes the process of preparing chilled water according to the present invention. The liquid nitrogen cold recovery device includes a liquid nitrogen transport vehicle 1, a self-pressurized liquid nitrogen tank 2, a first stop valve 3, a second stop valve 4, a heat exchange pipe 5, a liquid nitrogen spray gun 6, a first cryogenic pump 7, a heat exchanger 8, a chilled water storage device 9, a second cryogenic pump 10, a heat exchange tank 11, a filter 12, a compressor 13, and a gas storage tank 14. Figure 1 In the process of preparing chilled water by the liquid nitrogen cold recovery device, the first stop valve 3 and the second stop valve 4 are first closed; then the liquid nitrogen transported by the liquid nitrogen transport vehicle 1 is stored in the self-pressurized liquid nitrogen tank 2; the second stop valve 4 is opened, and the liquid nitrogen is directly sprayed into the heat exchange tank 11 containing anhydrous ethylene glycol through the second stop valve 4 and the liquid nitrogen spray gun 6 for vaporization. The vaporized nitrogen passes through the filter 12 from the heat exchange tank 11, and then enters the gas storage tank 14 for storage through the compressor 13. When the temperature of the ethylene glycol solution in the heat exchange tank 11 drops to -8°C, the first cryogenic pump 7 is started. At this time, the anhydrous ethylene glycol in the heat exchange tank 11 is transported to the heat exchanger 8 through the first cryogenic pump 7, and then returns to the heat exchange tank 11 after heat exchange in the heat exchanger 8. When the temperature of the ethylene glycol solution in the heat exchange tank 11 drops to -8°C, the chilled water with a temperature of 20°C is injected into the heat exchange tube 5 through the heat exchanger 8, and the chilled water is cooled by heat exchange through the heat exchange tube 5, and then transported to the chilled water storage device 9 through the second cryogenic pump 10. It should be understood that the present embodiment uses the liquid nitrogen cooling capacity recovery device disclosed in the first embodiment to illustrate the method for preparing chilled water of the present invention for exemplary purposes only, and any device that can directly mix liquid nitrogen with a coolant and then exchange heat between the coolant and the chilled water is applicable to the present invention.

[0083] In summary, according to the cold source cold energy recovery system and the method for preparing coolant of the present invention, the cold energy of the cold source recovered by directly mixing the cold source with the refrigerant can, on the one hand, avoid the waste of cold energy caused by direct heat exchange between the cold source and the air, and on the other hand, the recovered cold energy can be used to prepare the coolant, replacing the refrigerator to prepare the coolant, saving electric energy, thereby saving the cost of factory operation. At the same time, according to the cold source cold energy recovery system and the method for preparing coolant of the present invention, the cold energy is recovered and reused by directly mixing the cold source with the refrigerant, the cold energy recovery utilization rate is high, the recovery speed is fast, and the dual functions of cold source cold energy recovery and coolant preparation are realized at the same time, the equipment is compact, and the investment and operation costs are low.

[0084] The present invention has been described by the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A cold recovery system, characterized in that: The system comprises: Cold source supply device; A heat exchange device, the heat exchange device comprising a heat exchange tank connected to the cold source supply device and a heat exchange tube arranged in the heat exchange tank, a coolant is stored in the heat exchange tank, and the heat exchange tube forms an independent flow channel in the coolant; a device for supplying a liquid to be cooled, the device being in communication with an inlet of the heat exchange tube and being used for supplying the liquid to be cooled to the heat exchange tube, wherein the liquid to be cooled is chilled water; A coolant storage device connected to an outlet of the heat exchange tube; A heat exchanger connected between the liquid supply device to be cooled and the heat exchange tube, wherein the coolant is passed into the heat exchanger to perform primary heat exchange with the liquid to be cooled to form a primary coolant; Wherein, the heat exchange tank is connected with the cold source supply device so that the cold source of the cold source supply device can directly pass into the coolant; the heat exchanger is a tubular heat exchanger, the shell side inlet of the tubular heat exchanger is connected to the cooling liquid supply device, the shell side outlet of the tubular heat exchanger outputs the primary cooling liquid to the heat exchange tube, the tube side inlet of the tubular heat exchanger inputs the coolant in the heat exchange tank into the tubular heat exchanger, and the tube side outlet of the tubular heat exchanger outputs the coolant from the tubular heat exchanger to the heat exchange tank.

2. The system according to claim 1, characterized in that The cold source is liquid nitrogen, and the cooling liquid is chilled water.

3. The system according to claim 1, characterized in that The coolant is ethylene glycol.

4. The system according to claim 2, characterized in that The cold source supply device also includes a liquid nitrogen spray gun which is arranged at the bottom of the heat exchange tank and connected to the cold source supply device.

5. The system according to claim 4, characterized in that The liquid nitrogen spray gun comprises a regulating device for regulating the amount of liquid nitrogen sprayed into the coolant by the liquid nitrogen spray gun.

6. The system according to claim 1, wherein: A first cryogenic pump is provided between the tube inlet and the heat exchange tank.

7. The system according to claim 1, characterized in that A second cryogenic pump is provided between the outlet of the heat exchange tube and the coolant storage device.

8. The system according to claim 2, characterized in that The system also includes a nitrogen recovery device connected to the heat exchange tank, which is used to recover nitrogen after the liquid nitrogen is vaporized.

9. A method for preparing a cooling liquid, characterized in that: include: Directly mixing the cold source with the coolant to reduce the temperature of the coolant; Passing the coolant into a heat exchanger for pre-heat exchange, so that the heat exchanger is in a low temperature environment; Exchanging heat between the liquid to be cooled and the coolant to form a cooling liquid, wherein the liquid to be cooled is chilled water; Among them, the heat exchange of the liquid to be cooled and the coolant to form the coolant includes: performing a second heat exchange step of the liquid to be cooled and the coolant in the heat exchanger; setting a channel in the coolant during the mixing process of the cold source and the coolant, and performing a first heat exchange step of the liquid to be cooled through the channel.

10. The method according to claim 9, characterized in that The cold source is liquid nitrogen, and the cooling liquid is chilled water.

11. The method according to claim 10, characterized in that The step of mixing the cold source with the coolant includes spraying the liquid nitrogen into the coolant.

12. The method according to claim 11, characterized in that In the step of spraying the liquid nitrogen into the brine, the amount of the liquid nitrogen sprayed into the brine is adjusted.

13. The method according to claim 9, characterized in that When the temperature of the coolant is between -8°C and 0°C, the coolant is passed into the heat exchanger for pre-heat exchange.

14. The method according to claim 10, characterized in that The step of exchanging heat between the chilled water and the coolant is performed when the temperature of the coolant is between -8°C and 5°C.

15. The method according to claim 10, characterized in that The method further comprises the step of recovering the nitrogen.

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