Vapor compression system and control method thereof

Abstract

The invention discloses a steam compression system and a control method thereof. The steam compression system comprises a flash tank, at least one stage of steam compressor and a first water circulation pipe. The flash tank is used for enabling the steam generation water heated to the specified flash temperature to be subjected to flash evaporation under the negative pressure condition in the tank to become low-pressure steam; the steam compressor is used for compressing the low-pressure steam into superheated steam of which the saturation pressure is target condensing pressure; and the first water circulating pipe is used for guiding water of a target water source to motors of the steam compressors at all levels and exchanging heat with heat dissipation mechanisms of all the motors, and the water subjected to heat exchange returns to the target water source. Compared with the prior art, heat at the motor is recycled through water circulation, so that the enthalpy value of water for steam generation is increased, energy consumption needed by steam generation is reduced, and the comprehensive energy efficiency of the system is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of steam heating, and in particular relates to a steam compression system and a control method thereof. Background Art

[0002] Steam is widely used for heating in industrial applications, and one source of steam is an open-loop steam heat pump. This type of system typically consists of a water purification and deaeration system, a water pump, a heat pump (optional when the heat source temperature is too low), a steam generator, a steam compressor, a steam cooler, and supporting piping, valves, and a power supply. After being filtered through the water purification and deaeration system, tap water is fed into the steam generator for heat exchange with the heat source. The water absorbs heat and evaporates, converting it into low-pressure steam. This steam is then compressed by the steam compressor into high-temperature, high-pressure steam for industrial use.

[0003] During the compression process, the steam compressor's motor generates a significant amount of heat, equivalent to approximately 5% to 10% of the motor's power consumption. This heat is typically not effectively utilized, resulting in energy waste. Furthermore, when the steam compressor compresses steam, it causes the steam to superheat, which affects the compressor's efficiency. For example, when steam is compressed from a saturated pressure of 0.047 MPa to 0.182 MPa via a two-stage centrifugal steam compressor, spraying water in the middle to cool it down will improve overall energy efficiency by approximately 11% compared to not cooling it. Water spray cooling systems are difficult to control. Too little water spray results in insignificant cooling, while too much water spray can cause liquid hammering on the centrifugal steam compressor impeller. This overall solution presents significant challenges in implementation. Summary of the Invention

[0004] In view of this, an embodiment of the present application provides a steam compression system and a control method thereof to solve at least one of the above technical problems.

[0005] A first embodiment of the present application provides a steam compression system, comprising:

[0006] a flash tank, at least one steam compressor and a first water circulation pipe;

[0007] The flash tank is used to flash the steam generating water heated to a specified flash temperature into low-pressure steam under negative pressure conditions in the tank;

[0008] The steam compressor is used to compress the low-pressure steam into superheated steam with a saturation pressure equal to a target condensing pressure;

[0009] The first water circulation pipe is used to lead water from the target water source to the motors of each stage of the steam compressor and perform heat exchange with the heat dissipation mechanism of each motor. The water after the heat exchange is returned to the target water source.

[0010] The steam compression system according to the first aspect of the present application draws water from the target water source to the motors of each stage of the steam compressor through the first water circulation pipe, exchanges heat with the heat dissipation mechanism of each motor, and the water after heat exchange returns to the target water source. The heat at the motor is recovered through water circulation to increase the enthalpy value of the water for steam generation, reduce the energy consumption required for steam generation, and improve the overall energy efficiency of the system.

[0011] In a possible implementation, the system further includes a second water circulation pipe;

[0012] The second water circulation pipe is used to draw water from the target water source to the lubricating oil stations of each stage of the steam compressor, exchange heat with the cooling mechanism of each oil station, and the water after heat exchange returns to the target water source.

[0013] In a possible implementation, the system further includes a steam cooler and a third water circulation pipe;

[0014] The steam cooler is used to cool the superheated steam output by the steam compressor to the saturated state;

[0015] The third water circulation pipe is used to draw water from the target water source to the steam cooler, conduct indirect heat exchange with the steam cooler, and the water after heat exchange returns to the target water source.

[0016] In a possible implementation, the system further includes:

[0017] A heat pump, which is used to extract the waste heat from the heat source and release it into the water for steam generation, so as to raise the water temperature of the water for steam generation to the specified flash evaporation temperature.

[0018] In a possible implementation, the target water source is the stored water in the flash tank, the water for steam generation before being heated by the heat pump, or the heat source water before the waste heat is extracted by the heat pump.

[0019] In a possible implementation, the system further includes a first water storage tank for storing the water for steam generation before being heated by the heat pump.

[0020] In a possible implementation, the system further includes a second water storage tank for storing the heat source water before the waste heat is extracted by the heat pump.

[0021] In a possible implementation, a first water pump and a first control valve are provided on the first water circulation pipe;

[0022] The first water pump is used to pump the water from the target water source into the first water circulation pipe;

[0023] The first control valve is used to control the water flow rate of the first water circulation pipe.

[0024] In a possible implementation, a second water pump and a second control valve are provided on the second water circulation pipe;

[0025] The second water pump is used to pump the water of the target water source into the second water circulation pipe;

[0026] The second control valve is used to control the water flow rate of the second water circulation pipe.

[0027] In a possible implementation, a third water pump and a third control valve are provided on the third water circulation pipe;

[0028] The third water pump is used to pump the water of the target water source into the third water circulation pipe;

[0029] The third control valve is used to control the water flow rate of the third water circulation pipe.

[0030] The control method of the steam compression system according to the second aspect embodiment of the present application includes:

[0031] Detect whether the motor temperature of the steam compressor exceeds the first temperature range;

[0032] According to the motor temperature of the steam compressor exceeding the first temperature range, adjust the operating frequency of the first water pump and / or the opening degree of the first control valve until the motor temperature of the steam compressor is within the first temperature range.

[0033] The control method of the steam compression system according to the second aspect embodiment of the present application adjusts the cooling water flow rate in the first water circulation pipe by adjusting the operating frequency of the first water pump and / or the opening degree of the first control valve provided on the first water circulation pipe, so as to improve the cooling effect. The heat at the motor is recovered through water circulation to increase the enthalpy value of the water for steam generation, reduce the energy consumption required for steam generation, and improve the comprehensive energy efficiency of the system.

[0034] In a possible implementation, the method further includes:

[0035] Detect whether the temperature of the lubricating oil station of the steam compressor exceeds the second temperature range;

[0036] According to the temperature of the lubricating oil station of the steam compressor exceeding the second temperature range, adjust the operating frequency of the second water pump and / or the opening degree of the second control valve until the temperature of the lubricating oil station of the steam compressor is within the second temperature range.

[0037] In a possible implementation, the method further includes:

[0038] Detect whether the exhaust superheat degree of the steam cooler exceeds the third temperature range;

[0039] Adjust the operating frequency of the third water pump and / or the opening degree of the third control valve according to the exhaust superheat degree of the steam cooler exceeding the third temperature range until the exhaust superheat degree of the steam cooler is within the third temperature range. Description of the Drawings

[0040] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to denote the same components. In the drawings:

[0041] Attached Figure 1 Shows one of the schematic structural diagrams of a steam compression system provided by the present application;

[0042] Attached Figure 2 Shows another schematic structural diagram of a steam compression system provided by the present application;

[0043] Attached Figure 3 Shows a third schematic structural diagram of a steam compression system provided by the present application;

[0044] Attached Figure 4 Shows a fourth schematic structural diagram of a steam compression system provided by the present application;

[0045] Attached Figure 5 Shows the schematic structural diagram of a multi-parallel-axis single-stage multi-stage compressor;

[0046] Attached Figure 6 Shows the flowchart of a control method for a specific steam compression system provided by the present application.

[0047] The realization of the object of the present invention, functional features and advantages will be further described with reference to the embodiments and the drawings. Detailed Embodiments

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0049] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0050] In addition, in the present invention, descriptions such as "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plural" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, terms such as "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In addition, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0053] To make the above objects, features, and advantages of the present application more obvious and understandable, the following detailed description of the specific embodiments of the present application will be given with reference to the accompanying drawings.

[0054] The steam compression system provided by the embodiment of the present application includes a flash tank, at least one stage of steam compressor, and a first water circulation pipe. Specifically, at least one stage of steam compressor can be a single-stage steam compressor of a single machine, a multi-stage steam compressor of a single machine, or a multi-stage steam compressor in series of multiple machines.

[0055] Embodiment 1

[0056] Figure 1 is a schematic diagram of a steam compression system provided by an embodiment of the present application. As Figure 1 shown, the steam compression system includes: a heat pump (11 - 14), a flash tank 26, a steam compressor 31, and a first water circulation pipe. A first water pump 34 and a first control valve 35 are provided on the first water circulation pipe.

[0057] The heat pump is used to extract the waste heat in the heat source and release it into the water for steam generation, so as to raise the water temperature of the water for steam generation to the specified flash temperature.

[0058] Specifically, as Figure 1As shown, the heat pump is a system composed of a heat pump evaporator 11, a heat pump compressor 12, a heat pump condenser 13, and a heat pump throttle valve 14. Its operating principle is the same as that of a refrigeration system, which will not be elaborated here.

[0059] The heat source can be an industrial waste heat source, such as Figure 1 As shown, the heat source flows in from the A1 port of the pipeline and out from the A2 port, passing through the heat pump evaporator 11. The heat pump evaporator 11 extracts the waste heat in the heat source, and the heat pump condenser 13 releases the waste heat in the heat source into the water inlet pipe of the flash tank 26 to heat the steam generation water in the water inlet pipe of the flash tank 26.

[0060] Such as Figure 1 As shown, the inlet of the water inlet pipe of the flash tank 26 is B1. The flow rate is controlled by the fourth control valve 21 and is connected to the flash tank 26 through the fourth water pump 22, which can be used to pump out the stored water in the flash tank 26. After passing through the heat pump condenser 13, the steam generation water heated by the heat pump condenser 13 is pumped into the flash tank 26 through the fifth water pump 23, and the pumping method and flow rate are controlled by the fifth control valve 24 and the sixth control valve 25.

[0061] The flash tank 26 is used to make the heated steam generation water flash into low-pressure steam under the negative pressure condition in the tank. It should be noted that there are various ways to preheat the steam generation water, including but not limited to heat pumps.

[0062] The steam compressor 31 is used to suck the low-pressure steam in the flash tank 26 and compress it into superheated steam with a saturation pressure of the target condensation pressure, and output it through the port C1 of the main air outlet path. The superheated steam can be cooled to the saturated state by the steam cooler 38 and then sent to the heat-using link.

[0063] During the compression process, at least three parts in the steam compression system will generate excess heat: 1. The motor of the steam compressor will generate a large amount of waste heat (accounting for about 5% - 20% of the input electric energy) during operation, which is processed by the heat dissipation mechanism of the motor; 2. The friction between gears in the transmission system of the steam compressor will generate heat during operation, and this part of the heat will be taken out by the lubricating oil in the transmission system and processed in the oil station; 3. Superheat will be generated during steam compression. At this time, the enthalpy difference between the steam and the saturated steam at the same pressure is negative heat, which will hinder the compression, affect the system efficiency, and will also hinder the subsequent heat use and reduce the heat transfer efficiency.

[0064] The water in the flash tank needs to absorb heat when flashing under negative pressure. The flashing temperature is usually between 70 and 80 °C, and the flashing temperature difference is about 10 °C. When the large steam compressor motor runs, the temperature inside the motor can exceed 140 °C. The temperature of the lubricating oil in the compressor oil station before cooling is usually between 80 and 100 °C, and the temperature of the compressed steam can reach up to over 250 °C. Therefore, there is a sufficient heat exchange temperature difference with the water for steam generation.

[0065] The first water circulation pipe is used to lead the water from the target water source to the motors of each stage of the steam compressor, and exchange heat with the heat dissipation mechanism of each motor. The water after heat exchange returns to the target water source.

[0066] Optionally, the target water source can be the stored water in the flash tank, the water for steam generation before being heated by the heat pump, or the heat source water before the waste heat is extracted by the heat pump, or it can be other water sources, which are not limited in this application. Different water circulation pipes can be connected to different target water sources, which are not limited in this application.

[0067] As Figure 1 shown, the target water source is the stored water in the flash tank. The first water pump 34 pumps the stored water in the flash tank into the first water circulation pipe, and the first control valve 35 controls the water flow rate of the first water circulation pipe. The cooling water in the first water circulation pipe can take away part of the heat generated by the motor 32 of the steam compressor.

[0068] As Figure 1 shown, the above steam compression system can also include: a second water circulation pipe, which is used to lead the water from the target water source to the lubricating oil stations of each stage of the steam compressor, exchange heat with the cooling mechanism of each oil station, and the water after heat exchange returns to the target water source.

[0069] As Figure 1 shown, a second water pump 36 and a second control valve 37 are provided on the second water circulation pipe. The second water pump 36 is used to pump the water from the target water source into the second water circulation pipe; the second control valve 37 is used to control the water flow rate of the second water circulation pipe. The cooling water in the second water circulation pipe can take away part of the heat generated by the lubricating oil station 33 of the steam compressor.

[0070] As Figure 1 shown, the above steam compression system can also include: a steam cooler 38 and a third water circulation pipe; the steam cooler 38 is used to cool the superheated steam output by the steam compressor 31 to the saturated state; the third water circulation pipe is used to lead the water from the target water source to the steam cooler 38, indirectly exchange heat with the steam cooler 38, and the water after heat exchange returns to the target water source.

[0071] As Figure 1As shown, a third water circulation pipe is provided with a third water pump 28 and a third control valve 27. The third water pump 28 is used to pump water from a target water source into the third water circulation pipe; the third control valve 27 is used to control the water flow rate of the third water circulation pipe. Part of the heat of the superheated steam at the steam cooler 38 can be recovered by the cooling water in the third water circulation pipe.

[0072] In summary, Figure 1 As shown, in addition to the water inlet pipe, water return pipe, sewage discharge pipe, and steam outlet on the flash evaporation tank 26, a number of water circulation pipes are also provided. The water stored in the tank is led to the compressor motor 32, oil station 33, and steam cooler 38 in the system through a water pump. After heat exchange, it returns to the flash evaporation tank 26. At the same time, control valves are provided on each water circulation pipe to adjust the flow rate. It should be particularly noted that the steam cooler is an indirect heat exchange heat exchanger, such as a double-pipe heat exchanger, etc.

[0073] Figure 1 The specific working method of the steam compression system shown is: taking the flash evaporation tank 26 as the waste heat recovery center, in Figure 1 In the embodiment, there are three heat recovery pipelines in total. The first water circulation pipe pumps out the surface flash evaporation water through the first water pump 34 and sends it into the liquid cooling device of the steam compressor motor 32 to cool the motor; the second water circulation pipe flows into the cooling mechanism in the steam compression oil station 33 through the second water pump 36 to complete the cooling of the lubricating oil. The steam generation water after heat exchange and temperature rise returns to the flash evaporation tank to increase the water temperature in the tank and strengthen the flash evaporation; the third water circulation pipe pumps out the flash evaporation water through the third water pump 28 and sends it into the steam cooler 38 to indirectly exchange heat with the superheated steam (such as entering a double-pipe heat exchanger for heat exchange) and cool the superheated steam to saturation. The flash evaporation water after heat exchange also flows back to the flash evaporation tank. The motor, oil station, and outlet steam all have corresponding optimal temperature ranges. When the operating temperature is higher than the upper limit of the optimal temperature range, the frequency of the water pump motor on the corresponding water circulation pipe can be increased and / or the opening degree of the control valve on the corresponding water circulation pipe can be increased, thereby increasing the cooling water flow rate of the corresponding water circulation pipe and strengthening the cooling effect; when the operating temperature is lower than the lower limit of the optimal temperature range, the frequency of the water pump motor on the corresponding water circulation pipe and / or the opening degree of the control valve are reduced to reduce the cooling water flow rate to weaken the cooling effect.

[0074] The water temperature in the flash evaporation tank is monitored in real time, and the water temperature range in the flash evaporation tank is determined according to the set system discharge steam temperature. Here is a control example: when the suction temperature is set to 75 °C, the water temperature in the flash evaporation tank needs to be controlled between 74.5 and 75.5 °C. If the detected water temperature is lower than 74.5 °C, control the pre-stage heat pump compressor to increase the frequency by 2 hz; if the detected water temperature is higher than 75.5 °C, then control the pre-stage heat pump to reduce the frequency by 1 hz. It is verified every 30 s, and the control of the heat pump compressor stops after the water temperature returns to the predetermined water temperature range.

[0075] In some embodiments, such asFigure 2 As shown, the above steam compression system may further include a first water storage tank 41 for storing the steam generation water before being heated by the heat pump. Specifically, the first water storage tank 41 is arranged at the inlet B1 of the steam generation water. When the target water source is the steam generation water before being heated by the heat pump, the first water storage tank 41 serves as the waste heat recovery center, and each water circulation pipe can be connected to the first water storage tank 41. An independent tank body (the first water storage tank 41) is arranged on the water inlet side B1 of the steam generation water to serve as the heat recovery carrier. The steam generation water is stored in the water storage tank (the first water storage tank 41) before exchanging heat with the heat pump, and after being stabilized by the water storage tank, it is sent to each cooling point for heat recovery. The advantage of independently arranging the water storage tank is that the temperature of the cooling water is lower, the heat exchange temperature difference is larger, and more heat is recovered.

[0076] In some embodiments, such as Figure 3 As shown, the above steam compression system may further include a second water storage tank 42 for storing the heat source water before the waste heat is extracted by the heat pump. Specifically, the second water storage tank 42 is arranged at the inlet A1 of the heat source water. When the target water source is the heat source water before the waste heat is extracted by the heat pump, the second water storage tank 42 serves as the waste heat recovery center, and each water circulation pipe can be connected to the second water storage tank 42. An independent tank body (the second water storage tank 42) is arranged on the water inlet side A1 of the heat source water to serve as the heat recovery carrier. The heat source water is stored in the water storage tank (the second water storage tank 42) before exchanging heat with the heat pump, and after being stabilized by the water storage tank, it is sent to each cooling point for heat recovery. The advantage of independently arranging the water storage tank is that the temperature of the cooling water is lower, the heat exchange temperature difference is larger, and more heat is recovered.

[0077] In some embodiments, Figure 2 In the Figure 3 scheme, the independent tank body can be removed, and each water circulation pipe can directly draw water from the A1 or B1 water inlet pipe. Only the control valve needs to be controlled according to a certain logic to ensure that the water volume on the cooling side meets the requirements.

[0078] It is worth mentioning that the water circulation pipes can be flexibly arranged according to the actual situation: a. Completely independent hot water circuits can be set for each heat source, or multiple waste heat sources can be freely connected in series according to the actual scenario needs. For example, only one water path is led out from the flash evaporation tank and flows through the motor, oil station, and steam cooler once. b. When the oil temperature of the equipment is relatively low and the recovery value is not large, the waste heat recovery of the oil station can be abandoned. c. When higher requirements are placed on the compactness of the equipment, or for other considerations, the form of spray cooling can be used to cool the steam, and the recovery of the heat of the superheated part of the steam can be abandoned.

[0079] In some embodiments, such as Figure 4 As shown, the steam compression system can adopt a multi-stage steam compressor with multiple machines connected in series, and Figure 1The main difference of the single-machine system shown is that in order to obtain steam with a higher saturation temperature, multiple compressors need to be connected in series to increase the total pressure ratio. Multiple machines mean that there will be multiple compressors in the system ( Figure 4 in the case of two compressors 31-1 and 31-2 connected in series), so it is necessary to recover the waste heat in multiple compression systems. The water circulation pipe will be provided with branches to introduce the target water source into the motors and oil stations of each stage of the compressor respectively for heat exchange, and then return to the main pipe and return to the target water source. Considering reasons such as system cost and system complexity, a water pump and multiple control valves can be selected to control the cooling effect of each compressor.

[0080] In the scenario of multi-stage compression, a single-machine multi-stage compression system as shown in Figure 5 can be used to compress water vapor. In the case of single-machine multi-stage compression, there is only one motor waste heat source in the system, but there are multiple steam cooling heat sources available. For example, Figure 5 the single-machine four-stage compressor shown has 4 cooling points, 3 are located between stages, and 1 is located after compression.

[0081] Based on the above steam compression system, the present application also provides a control method for a steam compression system, including the following steps:

[0082] 101. Detect whether the motor temperature of the steam compressor exceeds the first temperature range (Te1~Te2);

[0083] 102. According to the motor temperature of the steam compressor exceeding the first temperature range (Te1~Te2), adjust the operating frequency of the first water pump and / or the opening degree of the first control valve until the motor temperature of the steam compressor is within the first temperature range.

[0084] Specifically, when the motor temperature of the steam compressor is lower than the lower limit Te1 of the first temperature range, reduce the frequency of the first water pump 34 and at the same time reduce the opening degree of the first control valve 35 to reduce the cooling water flow; when the motor temperature of the steam compressor is higher than the upper limit Te2 of the first temperature range, increase the frequency of the first water pump 34 and increase the opening degree of the first control valve 35 to improve the cooling effect.

[0085] The control method of the steam compression system in the embodiment of the present application introduces the water of the target water source to the motors of each stage of the steam compressor through the first water circulation pipe, and exchanges heat with the heat dissipation mechanism of each motor. The water after heat exchange returns to the target water source, and the heat at the motor is recovered through the water circulation to increase the enthalpy value of the water for steam generation, reduce the energy consumption required for steam generation, and improve the comprehensive energy efficiency of the system.

[0086] In some implementation manners, the control method of the above steam compression system may further include the following steps:

[0087] 103. Detect whether the temperature of the lubricating oil station of the steam compressor exceeds the second temperature range (To1 - To2).

[0088] 104. According to the fact that the temperature of the lubricating oil station of the steam compressor exceeds the second temperature range (To1 - To2), adjust the operating frequency of the second water pump and / or the opening degree of the second control valve until the temperature of the lubricating oil station of the steam compressor is within the second temperature range.

[0089] Specifically, when the temperature of the lubricating oil station is lower than the lower limit To1 of the second temperature range, reduce the frequency of the second water pump 36 and at the same time reduce the opening degree of the second control valve 37 to reduce the cooling water flow; when the temperature of the lubricating oil station is higher than the upper limit To2 of the second temperature range, increase the frequency of the second water pump 36 and increase the opening degree of the second control valve 37 to improve the cooling effect.

[0090] In some implementation manners, the control method of the above steam compression system may further include the following steps:

[0091] 105. Detect whether the exhaust superheat degree of the steam cooler exceeds the third temperature range (Ts1 - Ts2).

[0092] 106. According to the fact that the exhaust superheat degree of the steam cooler exceeds the third temperature range (Ts1 - Ts2), adjust the operating frequency of the third water pump and / or the opening degree of the third control valve until the exhaust superheat degree of the steam cooler is within the third temperature range.

[0093] Specifically, when the exhaust superheat degree of the steam cooler is lower than the lower limit Ts1 of the third temperature range, reduce the frequency of the third water pump 28 and at the same time reduce the opening degree of the third control valve 27 to reduce the cooling water flow; when the exhaust superheat degree of the steam cooler is higher than the upper limit Ts2 of the third temperature range, increase the frequency of the third water pump 28 and increase the opening degree of the third control valve 27 to improve the cooling effect.

[0094] For the sake of easy understanding, the present application provides a flowchart of a specific control method of a steam compression system as shown in Figure 6 the following.

[0095] Refer to Figure 1 and Figure 6, first, detect whether the water temperature in the flash tank is within the specified range (Tf1 to Tf2). If the water temperature is too high, reduce the operating frequency of the pre-system heat pump compressor 12 of the system to reduce energy consumption; if the water temperature is too low, increase the operating frequency of the heat pump compressor 12 to ensure the water temperature in the flash tank. Under any circumstances, the cooling system will operate, and the water supply at the three cooling points is controlled separately by the water circuits composed of three water pumps and control valves. When the temperature at the cooling point is lower than its respective set temperature range, reduce the water pump frequency and at the same time turn down the control valve to reduce the cooling water flow; when the temperature at the cooling point is higher than its respective set temperature range, increase the water pump frequency and open the control valve wider to improve the cooling effect.

[0096] It should be noted that:

[0097] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0098] Similarly, it should be understood that, in order to streamline the present application and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting the intention that the claimed present application requires more features than those expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim itself serves as a separate embodiment of the present application.

[0099] Those skilled in the art can understand that the modules in the devices in the embodiments can be adaptively changed and arranged in one or more devices different from this embodiment. The modules or units or components in the embodiments can be combined into a module or unit or component, and in addition, they can be divided into multiple sub-modules or sub-units or sub-components. Except that at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all the features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all the processes or units of any method or device so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) can be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

[0100] In addition, those skilled in the art can understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of this application and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

[0101] Each component embodiment of this application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of the functions of some or all of the components in the virtual machine creation device according to the embodiments of this application. This application can also be implemented as a device or device program (such as a computer program and a computer program product) for executing part or all of the methods described herein. Such a program for implementing this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0102] It should be noted that the above embodiments illustrate rather than limit this application, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim listing several devices, several of these devices can be embodied by the same hardware item. The use of the words first, second, and third, etc. does not denote any order. These words can be interpreted as names.

[0103] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural transformations made under the concept of the present invention by using the content of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A steam compression system, characterized in that: include: a flash tank, at least one steam compressor and a first water circulation pipe; The flash tank is used to flash the steam generating water heated to a specified flash temperature into low-pressure steam under negative pressure conditions in the tank; The steam compressor is used to compress the low-pressure steam into superheated steam with a saturation pressure equal to a target condensing pressure; The first water circulation pipe is used to lead water from the target water source to the motors of each stage of the steam compressor, exchange heat with the heat dissipation mechanism of each motor, and transport the water that has completed the heat exchange back to the target water source.

2. The vapor compression system according to claim 1, wherein: The system further comprises a second water circulation pipe; The second water circulation pipe is used to lead the water from the target water source to the lubricating oil stations of each stage of steam compressors, exchange heat with the cooling mechanism of each oil station, and transport the water that has completed the heat exchange back to the target water source.

3. The vapor compression system according to claim 1, wherein: The system also includes a steam cooler and a third water circulation pipe; The steam cooler is used to cool the superheated steam output by the steam compressor to a saturated state; The third water circulation pipe is used to lead water from the target water source to the steam cooler, perform indirect heat exchange with the steam cooler, and transport the water that has completed the heat exchange back to the target water source.

4. The vapor compression system according to claim 1, wherein: The system further comprises: The heat pump is used to extract waste heat from the heat source and release it into the water used for steam generation, thereby raising the temperature of the water used for steam generation to the specified flash temperature.

5. The vapor compression system according to claim 4, characterized in that The target water source is the stored water in the flash tank, the water used for steam generation before being heated by the heat pump, or the heat source water before waste heat is extracted by the heat pump.

6. The vapor compression system according to claim 5, characterized in that The system further includes a first water storage tank for storing water for steam generation before being heated by the heat pump.

7. The vapor compression system according to claim 5, wherein: The system further includes a second water storage tank for storing heat source water before waste heat is extracted by the heat pump.

8. The vapor compression system according to claim 1, wherein: The first water circulation pipe is provided with a first water pump and a first control valve; The first water pump is used to pump water from the target water source into the first water circulation pipe; The first control valve is used to control the water flow of the first water circulation pipe.

9. The vapor compression system according to claim 2, wherein: The second water circulation pipe is provided with a second water pump and a second control valve; The second water pump is used to pump water from the target water source into the second water circulation pipe; The second control valve is used to control the water flow of the second water circulation pipe.

10. The vapor compression system according to claim 3, wherein: The third water circulation pipe is provided with a third water pump and a third control valve; The third water pump is used to pump water from the target water source into the third water circulation pipe; The third control valve is used to control the water flow of the third water circulation pipe.

11. A method for controlling a vapor compression system according to any one of claims 8 to 10, characterized in that: include: detecting whether the motor temperature of the steam compressor exceeds a first temperature range; According to the motor temperature of the steam compressor exceeding the first temperature range, the operating frequency of the first water pump and / or the opening of the first control valve are adjusted until the motor temperature of the steam compressor is within the first temperature range.

12. The control method according to claim 11, characterized in that: The method further comprises: detecting whether the lubricating oil station temperature of the steam compressor exceeds a second temperature range; According to the lubricating oil station temperature of the steam compressor exceeding the second temperature range, the operating frequency of the second water pump and / or the opening of the second control valve are adjusted until the lubricating oil station temperature of the steam compressor is within the second temperature range.

13. The control method according to claim 11, characterized in that: The method further comprises: detecting whether the exhaust gas superheat of a steam cooler exceeds a third temperature range, wherein the steam cooler is used to cool the superheated steam output by the steam compressor to a saturated state; According to the exhaust gas superheat of the steam cooler exceeding the third temperature range, the operating frequency of the third water pump and / or the opening of the third control valve are adjusted until the exhaust gas superheat of the steam cooler is within the third temperature range.

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