Cooling water supply system and air separation plant

Abstract

The utility model provides a cooling water supply system and air separation equipment. In the cooling water supply system, a water return pipe system limits a first water return flow path and a second water return flow path which enable cooling water to reach a tower body after passing through a refrigerator and a cooler from a water pool of a water cooling tower. The water return line has a first additional line and a second additional line. The first additional pipeline is led out from a water diversion position downstream of the cooler in the second water return flow path and leads to a water supply position upstream of the refrigerator in the first water return flow path. And the second additional pipeline is led out from a water drainage position downstream of the refrigerator in the first water return flow path and leads to the water tank. The cooling water supply system can effectively ensure that the temperature of the cooling water entering the refrigerator is not too low at low cost.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the air separation field relates to a kind of air separation equipment, and particularly, it relates to a cooling water supply system. BACKGROUND

[0002] In the air separation field, the air cooling tower involved in the air separation equipment needs to use a refrigerator to provide chilled water. However, the refrigerator needs to use cooling water for cooling. However, in winter, the cooling water temperature is too low, which makes the refrigerant easily liquefy in the upper space of the condenser, and then mix with the lubricating oil in the lubricating system. This can cause poor lubrication, and then cause the temperature of the compressor bearing and rotor to be too high, causing failure problems.

[0003] Therefore, it is necessary to ensure that the cooling water temperature entering the refrigerator is not too low. How to effectively ensure this while minimizing costs is a problem to be solved. SUMMARY

[0004] The utility model aims to provide a cooling water supply system, which can effectively ensure that the cooling water temperature entering the refrigerator is not too low at a low cost.

[0005] The utility model provides a cooling water supply system. The cooling water supply system includes a cooling tower and a return water piping system. The cooling tower has a tower body and a water pool. The return water piping system defines a first return water flow path and a second return water flow path such that the cooling water reaches the tower body from the water pool through the refrigerator and the cooler respectively. The return water piping system has a first additional pipeline and a second additional pipeline. The first additional pipeline is drawn from a water introduction position downstream of the cooler in the second return water flow path and leads to a water supply position upstream of the refrigerator in the first return water flow path. The second additional pipeline is drawn from a water discharge position downstream of the refrigerator in the first return water flow path and leads to the water pool.

[0006] In one embodiment, the cooling water supply system further includes a pipeline adjustment assembly. The pipeline adjustment assembly includes a plurality of valves arranged in the return water piping system.

[0007] In one embodiment, the cooling water supply system switches between a first mode and a second mode by switching the switches of the plurality of valves. In the first mode, the return water piping system is arranged such that the cooling water reaches the tower body from the water pool through the refrigerator and the cooler via the first return water flow path and the second return water flow path respectively. In the second mode, the return water piping system is arranged such that the cooling water reaches the water pool from the water pool through the cooler and the refrigerator in sequence via a part of the second return water flow path, the first additional pipeline, a part of the first return water flow path, and the second additional pipeline.

[0008] In one embodiment, the aforementioned plurality of valves includes an isolation valve. The isolation valve is located in the first additional pipeline and / or the second additional pipeline.

[0009] In one embodiment, the cooling water supply system also includes a controller. The controller sends switching signals to multiple valves to achieve mode switching.

[0010] In one embodiment, the cooling water supply system also includes a detector for detecting the water temperature in the pool. The controller receives a temperature signal characterizing the water temperature from the detector, thereby sending switching signals to multiple valves.

[0011] In one embodiment, the return water system includes a first return water line and a second return water line that allow cooling water to flow from a water tank through a chiller and a cooler to the tower body. The first and second return water lines are connected in parallel, with their inlets connected to the same inlet line receiving water from the water tank, and their outlets connected to the same outlet line leading to the tower body. The inlet line, the first return water line, and the outlet line together constitute the first return water flow path, while the inlet line, the second return water line, and the outlet line together constitute the second return water flow path.

[0012] In one implementation, the cooling water supply system has a pump only in the inlet line.

[0013] In one embodiment, the water intake point is located at the outlet pipeline, the water supply point is located at the first return pipeline, and the drainage point is located at the first return pipeline. Thus, the cooling water sequentially passes through the inlet pipeline, the second return pipeline, the upstream section of the outlet pipeline located upstream of the water intake point, the first auxiliary pipeline, the intermediate section of the first return pipeline located between the water supply and drainage points, and the second auxiliary pipeline before returning from the water tank to the water tank.

[0014] In one embodiment, the cooling water supply system further includes a piping regulating assembly. The piping regulating assembly includes two isolation valves, which are respectively located on a first auxiliary pipeline and a second auxiliary pipeline. The piping regulating assembly also includes two switching valves, which are respectively located upstream and downstream of an intermediate section in the first return water pipeline.

[0015] This invention also provides an air separation unit. The air separation unit includes an air-cooled tower for pre-cooling the feed air. The air separation unit also includes the aforementioned cooling water supply system. The chiller is cooled by cooling water in the cooling water supply system, which then supplies chilled water to the air-cooled tower.

[0016] When using the aforementioned cooling water supply system and air separation equipment, for example, when the ambient temperature is not low, cooling water can be channeled from the water tank through the first and second return water paths, passing through the chiller and cooler respectively, before reaching the tower body. For example, when the ambient temperature is very low, the first additional pipeline can be used to guide the relatively warm cooling water, which has already passed through the cooler, into the chiller as cooling water, thus effectively ensuring that the temperature of the cooling water entering the chiller is not too low.

[0017] Furthermore, the aforementioned cooling water supply system fully considers the specific circumstances at this time, directly returning the cooling water to the pool rather than the tower body, which is sufficient to provide cool water downstream. In this way, although the cooling water return pump needs to overcome the pressure drop caused by the additional chiller, it can reduce the pressure drop caused by the tower height. Therefore, the two are balanced, eliminating the need to add or replace water pumps, and energy consumption is low. Consequently, both investment and operating costs can be very low.

[0018] Therefore, the above-mentioned cooling water supply system can ensure, in a low-cost and effective manner, that the temperature of the cooling water entering the chiller is not too low. Attached Figure Description

[0019] The advantages and spirit of this utility model can be further understood through the following detailed description and accompanying drawings.

[0020] Figure 1 This is a schematic diagram of an exemplary cooling water supply system according to an embodiment.

[0021] Figure 2 This is a schematic diagram of an exemplary cooling water supply system based on a comparative example. Detailed Implementation

[0022] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. However, it should be understood that this utility model is not limited to the embodiments described below, and the technical concept of this utility model can be implemented in combination with other known technologies or functions, or with other technologies that are the same as those known technologies.

[0023] For example, if the first feature described subsequently in the specification is formed above or on the second feature, this can include embodiments where the first and second features are formed by direct connection, or embodiments where an additional feature is formed between the first and second features, so that the first and second features are not directly connected. Furthermore, when the first element is described in a manner connected or combined with the second element, the description includes embodiments where the first and second elements are directly connected or combined with each other, as well as embodiments where one or more other intervening elements are incorporated to indirectly connect or combine the first and second elements with each other.

[0024] As described in the background section, chillers require a cooling water supply system to provide cooling water for cooling. However, the possibility of abnormalities caused by excessively low cooling water temperatures in winter needs to be considered.

[0025] Therefore, the analysis suggests that the problem can be solved by using the relatively warm cooling water that has already passed through other coolers to send to the refrigeration unit.

[0026] However, a further problem arises: the additional pressure drop at the chiller necessitates increasing the discharge pressure of the cooling water pump, which significantly increases energy consumption and investment costs.

[0027] Therefore, a cooling water supply system according to this utility model is provided. For example... Figure 1 As shown, an exemplary cooling water supply system 10 according to an embodiment of the present invention includes a cooling tower 1 and a return water pipe system 2. The cooling tower 1 has a tower body 11 and a water tank 12.

[0028] It is understood that the accompanying drawings in this article are for illustrative purposes only and are not necessarily drawn to scale. They should not be construed as limiting the scope of protection of this utility model. It is also understood that in the cooling tower 1, a fan is typically installed in the tower body 11 to cool the incoming water entering from the middle or upper part of the tower body 11 to a lower temperature before it is discharged downwards under gravity. The water tank 12 is placed at the bottom of the tower body 11 to receive the cooler drainage flowing down from the tower body 11, thus allowing cooling water q0 to be output.

[0029] The return water system 2 defines the cooling water q0 to reach the first return water flow path s1 and the second return water flow path s2 from the water tank 12 through the chiller 20 and the cooler 30 respectively.

[0030] A refrigeration unit is a machine that provides chilled water, which is cooled by passing cooling water through its condenser. A cooler, on the other hand, is another component that helps cool streams or parts, such as the aftercooler commonly found in air separation equipment. The aftercooler cools the normally hot air exiting the compressor or turbocharger to below 40°C.

[0031] The return water system 2 has a first auxiliary pipeline 23 and a second auxiliary pipeline 24. The first auxiliary pipeline 23 is led out from the water inlet position P1 downstream of the cooler 30 in the second return water flow path s2 and leads to the water supply position P2 upstream of the chiller 20 in the first return water flow path s1. The second auxiliary pipeline 24 is led out from the drainage position P3 downstream of the chiller 20 in the first return water flow path s1 and leads to the water tank 12.

[0032] It is understood that the terms "pipeline," "pipeline," and "pipe segment" used in this text refer to the path through which the flow stream passes, and do not limit the physical form of the corresponding components. Taking "pipeline" as an example, a pipeline can refer to a segment of a complete pipeline. A pipeline can also be a combination of multiple pipelines connected sequentially. These multiple pipelines can be connected by pipe fittings or other pipeline components such as valves. The space through which the flow stream passes in the pipe fittings or other pipeline components can also be considered part of the pipeline. Furthermore, when using the term "flow path," it is particularly desirable to describe the route taken by the flow stream. As mentioned earlier, when describing the first and second flow paths, it is generally necessary to distinguish between them, but it is not excluded that they may share some sections, such as the first return water flow path s1 and the second return water flow path s2, which will be described in detail later.

[0033] It can also be understood that when the text describes a stream entering the first and second elements sequentially, or uses similar descriptions, it only indicates the order in which the stream enters the first and second elements. It does not exclude the possibility that the stream passes through the second element between the first and second elements, nor does it exclude the possibility that the stream passes through the second element before or after the first element. For example, cooling water q0 is sent from the water tank 12 to the tower body 11, which in fact passes through multiple components.

[0034] In the aforementioned cooling water supply system 10, the first return water flow path s1 and the second return water flow path s2 allow cooling water q0 to flow from the water tank 12 through the chiller 20 and the cooler 30 respectively before reaching the tower body 11, meeting daily needs. Simultaneously, the first auxiliary pipeline 23 utilizes the relatively warm cooling water, which has already passed through the cooler 30, to flow into the chiller 20, ensuring that even when the cooling water source temperature is low, the temperature of the cooling water entering the chiller 20 is not too low, preventing any abnormal problems. Furthermore, the inventors have fully considered that the first auxiliary pipeline 23 is activated in winter, when the ambient temperature is very low. Therefore, the relatively warm cooling water q0, having passed through the cooler 30 and chiller 20, is directly returned to the water tank 12 without needing to be sent to the tower body 11, thus providing sufficient cool water downstream. This eliminates the need to overcome the hydraulic pressure difference caused by the height of the tower body 11. Typically, the hydraulic pressure difference along the height of the tower body 11 is significant, even exceeding the pressure difference caused by the chiller 20.

[0035] In this way, only the first additional pipeline 23 and the second additional pipeline 24 need to be added to the basic configuration of the first return water flow path s1 and the second return water flow path s2. There is no need to replace the cooling water return pump (pump 3 shown in the figure) or add an additional booster pump. Therefore, the investment cost is very low and the operating cost is also very low.

[0036] It is understood that the terms "first" and "second" are used for descriptive purposes only and do not refer to limitations on chronological order, quantity, or importance. They should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated, but are merely used to distinguish one technical feature from another in this technical solution. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of that feature. In this text, "multiple" means two or more (i.e., more than two), unless otherwise explicitly specified. Similarly, qualifiers like "one" appearing in this text do not refer to limitations on quantity, but rather describe technical features not previously mentioned. Likewise, unless a noun is modified by a specific quantifier, it should be considered to include both singular and plural forms in this text; the technical solution may include either a singular or plural number of that technical feature.

[0037] The cooling water supply system 10 may also include a piping regulating assembly 4. The piping regulating assembly 4 includes multiple valves disposed in the return water piping system 2, such as valves 41, 42, 43, 44, etc., mentioned later. The cooling water supply system 10 switches between a first mode M1 and a second mode M2 ​​by switching the opening and closing of the aforementioned multiple valves.

[0038] In the first mode M1, the return water system 2 is configured such that cooling water q0 flows from the water tank 12 through the chiller 20 and the cooler 30 via the first return water flow path s1 and the second return water flow path s2, respectively, to the tower body 11. In the second mode M2, the return water system 2 is configured such that cooling water q0 flows sequentially from the water tank 12 through a portion of the second return water flow path s2 (i.e., the portion upstream of the water intake position P1), the first additional pipeline 23, a portion of the first return water flow path s1 (i.e., the portion between the water supply position P2 and the drainage position P3), and the second additional pipeline 24, sequentially passing through the cooler 30 and the chiller 20 before returning to the water tank 12. This arrangement facilitates mode switching according to actual needs. The first mode M1 and the second mode M2 ​​can respectively correspond to operating conditions with higher water temperatures, such as summer, and operating conditions with lower water temperatures, such as winter.

[0039] The aforementioned valves include isolation valves, such as isolation valves 43 and 44 described later. Isolation valves may be located on a first additional line 23 and / or a second additional line 24.

[0040] The term "and / or" as used herein includes any and all combinations of one or more of the related listed items. Unless otherwise stated, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood in the art to which this invention pertains. It should also be understood that terms, such as those defined in common dictionaries, should be understood to have the same meaning as they have in the context of this specification and the related art, and should not be interpreted in an idealized or overly formal sense unless expressly stated herein. For the sake of brevity and / or clarity, well-known functions or constructions may not be described in detail.

[0041] The cooling water supply system 10 may also include a controller 6. The controller 6 sends switching signals to the aforementioned multiple valves to achieve mode switching. In this way, automatic control can be achieved. The controller may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof.

[0042] The cooling water supply system 10 also includes a detector 9 for detecting the water temperature in the water tank 12. The controller 6 receives a temperature signal characterizing the water temperature from the detector 9, and then sends the aforementioned switching signals to the plurality of valves. This further enhances automation. The detection element can be, for example, various sensors, such as pressure sensors, optical sensors, ultrasonic sensors, etc. Figure 1 The signal connections between controller 6, detector 9, and various valves are schematically shown in dashed lines. It can be understood that the signal connections can be wired or wireless.

[0043] The return water system 2 has a first return water line 21 and a second return water line 22 that allow cooling water q0 to travel from the water tank 12 through the chiller 20 and the cooler 30 to the tower body 11.

[0044] The first return water pipeline 21 and the second return water pipeline 22 are connected in parallel. Both inlets are connected to the same inlet pipeline 25 that receives water from the water tank 12, and both outlets are connected to the same outlet pipeline 26 leading to the tower body 11. The inlet pipeline 25, the first return water pipeline 21, and the outlet pipeline 26 together constitute the first return water flow path s1, while the inlet pipeline 25, the second return water pipeline 22, and the outlet pipeline 26 together constitute the second return water flow path s2.

[0045] The cooling water supply system 10 has a pump 3 installed only in the inlet pipe 25. That is, the cooling water supply system 10 has one and only one pump 3 installed in the inlet pipe 25. This does not preclude the cooling water supply system 10 from including multiple pumps 3 installed in the inlet pipe 25, but rather limits this to the fact that in this case, these multiple pumps 3 can only be installed in the inlet pipe 25, and not elsewhere. For example, multiple pumps 3 can be installed in parallel in the inlet pipe 25. The pump 3 can be referred to as a cooling water return pump.

[0046] like Figure 1 As shown, the water intake point P1 can be located at the outlet pipe 26. The water supply point P2 can be located at the first return water pipe 21, that is, upstream of the chiller 20 on the first return water pipe 21. The drainage point P3 is located at the first return water pipe 21, that is, downstream of the chiller 20 on the first return water pipe 21. Thus, the cooling water q0 sequentially passes through the inlet pipe 25, the second return water pipe 22, the upstream section 261 of the outlet pipe 26 located upstream of the water intake point P1, the first auxiliary pipe 23, the intermediate pipe section 210 of the first return water pipe 21 located between the water supply point P2 and the drainage point P3, and the second auxiliary pipe 24, returning from the water tank 12 to the water tank 12. It can be understood that the intermediate pipe section 210 essentially includes the path through which the cooling water q0 passes within the chiller 20. It can also be understood that the statement that the outlet water line 26 is drawn from the upstream of the chiller 20 can include the case where the outlet water line 26 is connected to the cooling water inlet of the chiller 20.

[0047] It is understandable that the text uses "upstream" and "downstream" to describe relative locations, which are all relative to the flow direction of the stream in the corresponding pipeline.

[0048] As mentioned earlier, the cooling water supply system 10 may also include a piping regulating assembly 4. The piping regulating assembly 4 may include two isolation valves 43 and 44. The two isolation valves 43 and 44 may be respectively installed on the first auxiliary pipeline 23 and the second auxiliary pipeline 24. This facilitates control.

[0049] The pipeline regulating assembly 4 may also include two switching valves 41 and 42. The two switching valves 41 and 42 may be respectively located upstream and downstream of the intermediate pipe section 210 in the first return water pipeline 21 (that is, upstream of the water supply position P2 and downstream of the drainage position P3).

[0050] Figure 2 A cooling water supply system 10a is shown as a comparative example. In the cooling water supply system 10a, the return water pipe system 2a includes a third pipe 23a connected in parallel with both the first return water pipe 21 and the second return water pipe 22. The third pipe 23a extends from a position P1a downstream of the cooler 30 in the second return water pipe 22 to a position P2a upstream of the chiller 20 in the first return water pipe 21.Figure 2 In this configuration, position P1a is located downstream of the cooler 30 on the second return water line 22. A valve 45 is installed in the third line 23a, and a valve 46 is also installed downstream of position P1a and before the outlet position P6 on the second return water line 22. Figure 2 In this process, by closing switching valves 41 and 46 while simultaneously opening valve 45, cooling water q0 can pass sequentially through cooler 30 and chiller 20 before reaching tower 11. However, since pump 3 needs to overcome the pressure drop of both cooler 30 and chiller 20, and also needs to supply water to both cooler 30 and chiller 20 simultaneously, a high-power, high-flow-rate pump is required. This not only results in high procurement costs but also significant energy consumption. Furthermore, when the two systems are not connected in series, pump 3 typically operates at lower power, which is not only wasteful but may also damage the pump.

[0051] Compared to the comparative example, the cooling water supply system 10 described above, through its pipeline layout, returns the cooling water q0, which has passed through both the cooler 30 and the chiller 20, to the water tank 12. The pump 3 can still be configured to pump the cooling water q0 separately through either the cooler 30 or the chiller 20 to the tower body 11. In this way, only two additional pipelines are needed, significantly reducing investment costs and energy consumption.

[0052] This utility model also provides an air separation unit 100. The air separation unit 100 includes an air-cooled tower 60 for precooling the feed air. The air separation unit 100 also includes a cooling water supply system 10. The chiller 20 is cooled by cooling water q0 in the cooling water supply system 10, and then supplies chilled water q1 to the air-cooled tower 60.

[0053] It is important to understand that chilled water q1 can be drawn from the nitrogen water tower (not shown) of the air separation unit 100 and frozen after being fed into the chiller 20; it is not the cooling water q0 used here to cool the chiller 20. The air-cooled tower 60, the chiller 20, the nitrogen water tower, etc., together constitute the precooling system of the air separation unit 100.

[0054] Unless otherwise clearly indicated, each aspect or embodiment defined herein may be combined with any other aspect or embodiment. In particular, any feature indicated as preferred or advantageous may be combined with any other feature indicated as preferred or advantageous.

[0055] The embodiments described in this specification are merely preferred embodiments of the present invention. These embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of the present invention. All technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation should be within the scope of the present invention.

Claims

1. A cooling water supply system, comprising a cooling tower and a return water piping system, wherein the cooling tower has a tower body and a water tank, and the return water piping system defines a first return water flow path and a second return water flow path from the water tank through a chiller and a cooler respectively to the tower body, characterized in that, The return water system has a first auxiliary pipeline and a second auxiliary pipeline. The first auxiliary pipeline is led out from the water intake position downstream of the cooler in the second return water flow path and leads to the water supply position upstream of the chiller in the first return water flow path. The second auxiliary pipeline is led out from the drainage position downstream of the chiller in the first return water flow path and leads to the water tank.

2. The cooling water supply system as described in claim 1, characterized in that, It also includes a pipeline regulating assembly, which includes multiple valves disposed in the return water pipeline system; The cooling water supply system switches between a first mode and a second mode by switching the multiple valves. In the first mode, the return water system is configured such that cooling water flows from the water tank through the chiller and cooler to the tower via the first return water path and the second return water path, respectively. In the second mode, the return water system is configured such that cooling water flows from the water tank through the cooler and chiller in sequence via a portion of the second return water path, the first additional pipeline, a portion of the first return water path, and the second additional pipeline, and then returns to the water tank.

3. The cooling water supply system as described in claim 2, characterized in that, The plurality of valves includes an isolation valve located on the first additional pipeline and / or the second additional pipeline.

4. The cooling water supply system as described in claim 2, characterized in that, It also includes a controller that sends switching signals to the plurality of valves to achieve mode switching.

5. The cooling water supply system as described in claim 4, characterized in that, It also includes a detector for detecting the water temperature in the pool, and the controller receives a temperature signal characterizing the water temperature from the detector, thereby sending the switching signal to the plurality of valves.

6. The cooling water supply system as described in claim 1, characterized in that, The return water system has a first return water line and a second return water line that allow cooling water to flow from the water tank through the chiller and the cooler to the tower body. The first return water line and the second return water line are connected in parallel. Their inlets are all connected to the same inlet water line that receives water from the water tank, and their outlets are all connected to the same outlet water line that leads to the tower body. The inlet water line, the first return water line, and the outlet water line together constitute the first return water flow path, and at the same time, the inlet water line, the second return water line, and the outlet water line together constitute the second return water flow path.

7. The cooling water supply system as described in claim 6, characterized in that, The cooling water supply system has a pump installed only in the inlet pipeline.

8. The cooling water supply system as described in claim 6, characterized in that, The water intake point is located at the water outlet pipeline, the water delivery point is located at the first return water pipeline, and the drainage point is located at the first return water pipeline. Thus, the cooling water sequentially passes through the water inlet pipeline, the second return water pipeline, the upstream section of the water outlet pipeline located upstream of the water intake point, the first auxiliary pipeline, the intermediate section of the first return water pipeline located between the water delivery point and the drainage point, and the second auxiliary pipeline to return from the water tank to the water tank.

9. The cooling water supply system as described in claim 8, characterized in that, It also includes a pipeline regulating assembly, which includes two isolation valves, which are respectively disposed on the first additional pipeline and the second additional pipeline; The pipeline regulating assembly also includes two switching valves, which are respectively located upstream and downstream of the intermediate pipe section in the first return water pipeline.

10. An air separation unit, comprising an air-cooled tower for precooling feed air, characterized in that, The air separation unit further includes a cooling water supply system as described in any one of claims 1 to 9, wherein the chiller is cooled by cooling water in the cooling water supply system, thereby providing chilled water to the air-cooled tower.

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