JP2020070975A - Working medium recovery method - Google Patents

Abstract

To provide a technique to recover a working medium from a thermal energy recovery device so as to enable the recovered working medium to be recycled.SOLUTION: A working medium recovery method is to recover a working medium, a zeotropic mixture made by mixing a first medium component with a second medium component having higher saturation vapor pressure than the first medium component, from a thermal energy recovery device which recovers thermal energy by circulating the working medium through a Rankine cycle. The working medium recovery method comprises the processes to: selectively vaporize the first medium component in the working medium and recover the vaporized first medium component in a manner that creates a pressure environment having pressure lower than the saturation vapor pressure of the second medium component and higher than the saturation vapor pressure of the first medium component at a location where the working medium is in a liquid phase; and recover the second medium component remained in the thermal energy recovery device after selectively recovering the first medium component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a recovery method for recovering a working medium from a heat energy recovery device that recovers heat energy by circulating a non-azeotropic mixed medium as a working medium under a Rankine cycle.

  Various heat energy recovery devices have been developed that circulate a working medium under a Rankine cycle to recover heat energy (see Patent Document 1). The working medium exchanges heat with the heating medium in the evaporator and changes its phase from the liquid phase to the gas phase. At this time, the working medium recovers heat energy from the heating medium. The working medium that has recovered the heat energy expands in the expander and performs a predetermined work. That is, the thermal energy recovered by the working medium is converted into the power of the expander. The working medium in the gas phase after working in the expander is then converted into the working medium in the liquid phase in the condenser. The liquid-phase working medium is supplied to the evaporator again by the pump.

JP, 2017-190741, A

  A non-azeotropic mixed medium may be used as the working medium. The non-azeotropic mixed medium contains a plurality of types of medium components (hereinafter, referred to as a first medium component and a second medium component) that differ from each other in saturated vapor pressure. These medium components have a property as a mere mixture in which the dew point and the boiling point are separated.

  When the working medium leaks from the thermal energy recovery device, it is preferable that the working medium remaining in the thermal energy recovery device after the leakage is recovered and reused. However, when leakage of the working medium occurs in the section where the working medium is in the gas phase state (that is, the section from the evaporator to the condenser), the recovered working medium is reused under the conventional technique. It is difficult to do this for the following reasons.

  Leakage amounts of the first medium component and the second medium component are affected by their saturated vapor pressures. If the saturated vapor pressure of the first medium component is lower than the saturated vapor pressure of the second medium component, the leak amount of the first medium component becomes larger than the leak amount of the second medium component. In this case, the ratio of the first medium component to the working medium remaining in the heat energy recovery device is smaller than that before the leakage. Even if the working medium remaining in the heat energy recovery device is recovered, the mixing ratio of the first medium component and the second medium component in the working medium is different from that before the leakage, and thus the recovered working medium is used. Cannot achieve the desired performance.

  It is an object of the present invention to provide a technique for recovering a working medium from a heat energy recovery device so that the recovered working medium can be reused.

  A recovery method according to one aspect of the present invention uses a non-azeotropic mixed medium in which a first medium component and a second medium component having a higher saturated vapor pressure than the first medium component are mixed as a working medium for Rankine cycle It is used to recover the working medium from a heat energy recovery device that circulates below to recover heat energy. A recovery method selectively creates the first medium component in the liquid working medium by creating a pressure environment below the saturated vapor pressure of the second medium component and above the saturated vapor pressure of the first medium component. Vaporizing and recovering the vaporized first medium component, and recovering the second medium component remaining in the thermal energy recovery device after selectively recovering the first medium component. I have it.

  According to the above configuration, since the second medium component is recovered after the first medium component vaporized from the liquid-phase working medium is selectively recovered, the recovery amounts of the first medium component and the second medium component are different. Turns out. Therefore, it is possible to know how much each of the first medium component and the second medium component needs to be replenished to obtain an appropriate mixing ratio of the first medium component and the second medium component. After the first medium component and the second medium component are respectively replenished by an appropriate replenishment amount, when the replenished first medium component and the second medium component are mixed, a reusable working medium is generated in the heat energy recovery device. Produced.

  Selectively recovering the first medium component for the above configuration includes (i) measuring the temperature of the working medium, and (ii) the first medium component corresponding to the measured temperature. Creating the pressure environment above the saturated vapor pressure of the second medium component above the saturated vapor pressure and corresponding to the measured temperature.

  According to the above configuration, since the pressure environment is set based on the temperature of the working medium, the first medium component is selectively vaporized even if the temperature of the working medium changes.

  Selectively recovering the first medium component with respect to the above configuration includes reducing a pressure in a pipe connected from the thermal energy recovery device to the vacuum device by using a vacuum device to create the pressure environment. There is.

  According to the above configuration, the pressure in the pipe connecting the heat energy recovery device to the vacuum device is reduced by the vacuum device and a pressure environment for selectively vaporizing the first medium component is created. Evaporate in the pipe. Since the pipe is connected to the vacuum device, the vaporized first medium component is sucked and collected by the vacuum device.

  Selectively collecting the first medium component with respect to the above configuration includes (i) sucking the vaporized first medium component using the vacuum device, and (ii) sucking the first medium component. Compressing the components, (iii) cooling and liquefying the compressed first medium component, and (iv) storing the liquefied first medium component.

  According to the above configuration, since the first medium component sucked by the vacuum device is compressed and then liquefied, the volume of the stored first medium component becomes small.

  With respect to the above configuration, recovering the second medium component includes recovering the second medium component while maintaining the liquid phase of the second medium component.

  According to the above configuration, since the second medium component is recovered in the liquid phase, the volume of the recovered second medium component does not become excessively large as compared with the gas phase second medium component.

  With regard to the above configuration, selectively recovering the first medium component includes stopping the Rankine cycle, and upstream and downstream of the expander through a bypass that bypasses the expander that is responsible for the expansion process of the Rankine cycle. Allowing the flow of the first medium component to and from the site.

  When the recovery position for selectively recovering the first medium component is set at one of the upstream part and the downstream part of the expander, the pressure environment for the selective recovery of the first medium component is set. The spatial region expands around the recovery position as the recovery amount of the first medium component increases. According to the above configuration, since there is a detour that bypasses the expander, the above-mentioned space region can be expanded to the other of the upstream part and the downstream part through the detour without being blocked by the stopped expander. .. As a result, the working medium existing in the other of the upstream portion and the downstream portion is also exposed to the pressure environment for the selective recovery of the first medium component. As a result, the first medium component can be vaporized also from the working medium existing in the other of the upstream portion and the downstream portion. The first medium component vaporized at the other of the upstream portion and the downstream portion reaches the collection position through the detour and is collected.

  With respect to the above configuration, the recovery method further comprises measuring the recovered first medium component and the recovered second medium component.

  According to the above configuration, since the recovery amounts of the first medium component and the second medium component can be known, the first medium component and the second medium component can be respectively obtained in order to obtain an appropriate mixing ratio of the first medium component and the second medium component. You can see how much you need to replenish.

  The technique described above enables the recovery of the working medium from the thermal energy recovery device so that the recovered working medium can be reused.

1 is a schematic diagram of an exemplary heat energy recovery device. It is a schematic ph diagram of the working medium circulated in the heat energy recovery device. It is a schematic block diagram showing an example functional composition of a control system which controls a recovery operation for recovering a working medium. 7 is a schematic flowchart showing an exemplary control operation of a control unit. It is a schematic diagram of the 1st recovery equipment which collects the 1st medium ingredient of a working medium from a thermal energy recovery device in the section between a condenser and a pump.

  FIG. 1 is a schematic diagram of an exemplary heat energy recovery device 100. The thermal energy recovery device 100 is described with reference to FIG.

  The thermal energy recovery device 100 is configured to circulate a non-azeotropic mixed medium as a working medium under a Rankine cycle to recover thermal energy. One of the plurality of components contained in the non-azeotropic mixed medium is referred to as a "first medium component" in the following description. Another component having a higher saturated vapor pressure than the first medium component is referred to as a "second medium component" in the following description. The types and mixing ratios of the first medium component and the second medium component are determined so that desired characteristics can be obtained. For example, HFC and HFO may be used as the first medium component and the second medium component, respectively.

  The heat energy recovery device 100 is configured to generate electric power from the heat energy recovered as a result of circulating the working medium under the Rankine cycle. That is, the thermal energy recovery device 100 includes a circulation part that circulates the working medium under a Rankine cycle, and a power generation part that generates electric power by using the recovered thermal energy. In addition to the circulation part and the power generation part, the thermal energy recovery device 100 includes a circulation assisting part that allows the working medium to circulate in the thermal energy recovery device 100 while the expansion process of the Rankine cycle is stopped. The circulation assisting portion is used, for example, when the heat energy recovery device 100 is started up. The circulation part, the power generation part, and the circulation support part are described below.

  The circulation part has a pump 111 that discharges a liquid-phase working medium, a circulation path 116 configured so that the working medium discharged from the pump 111 returns to the pump 111, an evaporator 112 disposed on the circulation path 116, and an expander. Includes 113 and condenser 114. The evaporator 112, the expander 113, and the condenser 114 are arranged so that the working medium discharged from the pump 111 passes through these in order. The evaporator 112 is a device responsible for the evaporation process of the Rankine cycle, and causes the liquid-phase working medium discharged from the pump 111 to exchange heat with a heating medium (for example, exhaust gas from an internal combustion engine) generated from another facility. It is configured to recover thermal energy. As a result of heat exchange with the heating medium, the working medium evaporates (i.e. enters the gas phase). The working medium in the gas phase flows into the expander 113 that is responsible for the expansion process of the Rankine cycle. The working medium in the vapor phase expands in the expander 113 and causes the rotor of the expander 113 to rotate. The rotary motion of the expander 113 is used for power generation at the power generation site. The working medium expanded by the expander 113 flows into the condenser 114 which is responsible for the condensation process of the Rankine cycle. The condenser 114 is configured to exchange heat between the working medium and cooling water having a temperature lower than that of the working medium. As a result of the heat exchange with the cooling water, the working medium is cooled and becomes the liquid phase. The liquid-phase working medium is sucked by the pump 111 and discharged again to the evaporator 112.

  The power generation site produces electric power while the working medium circulates through the pump 111, the evaporator 112, the expander 113 and the condenser 114.

  The power generation site includes a generator 115 mechanically connected to the rotor of expander 113. The generator 115 rotates according to the rotational movement of the rotor of the expander 113 to generate electric power.

  Circulation of the working medium may be required during a period other than the period in which the generator 115 is producing electric power (for example, during start-up work of the heat energy recovery device 100). In this case, the circulation assisting portion is used for circulating the working medium.

  The circulation assisting portion includes a bypass 140 that forms a flow path that bypasses the expander 113, and a valve body 141 that is disposed on the bypass 140. The bypass 140 is connected to an upstream portion (that is, a section between the evaporator 112 and the expander 113) and a downstream portion (that is, a section between the expander 113 and the condenser 114) of the expander 113. The valve body 141 arranged on the bypass 140 is opened when it is necessary to circulate the working medium while the expander 113 is stopped. When the valve body 141 is opened, the working medium can bypass the expander 113 and flow from the upstream part to the downstream part of the expander 113.

  The saturated vapor pressure characteristics of the first medium component and the second medium component contained in the working medium and the problems associated with utilizing a non-azeotropic mixed medium as the working medium will be described with reference to FIGS. 1 and 2. FIG. 2 is a schematic ph diagram of the working medium.

  As shown in FIG. 2, the saturated vapor pressure of the first medium component is lower than the saturated vapor pressure of the second medium component. Therefore, the first medium component vaporizes at a lower pressure than the second medium component. In other words, the first medium component is easier to vaporize than the second medium component. The difference in easiness of vaporization is that the first medium component and the second medium component when the vapor-phase working medium leaks from the heat energy recovery device 100 (for example, when the circulation path 116 of the heat energy recovery device 100 is damaged). Resulting in a difference in the amount of leakage. Since the first medium component is more easily vaporized than the second medium component, the leak amount of the first medium component exceeds the leak amount of the second medium component. A leakage point where the first medium component and the second medium component leak is indicated by a point L drawn on the flow path of the working medium from the evaporator 112 to the expander 113 in FIG. 1.

  When the working medium leaks out, it becomes unclear how much each of the first medium component and the second medium component has been lost. Even if the working medium is recovered from the circulation path 116 after the leakage portion of the working medium is repaired while keeping the mixed state of the first medium component and the second medium component, the first medium component in the recovered working medium is recovered. Also, the mixing ratio of the second medium component may be significantly different from the mixing ratio before leakage. Therefore, the recovered working medium is not suitable for reuse.

  Techniques for reclaiming the working medium for reuse are described with reference to FIGS.

  FIG. 1 shows a first recovery facility 120 exclusively used for recovering a first medium component in a working medium and a second recovery facility 130 exclusively used for recovering a second medium component in a working medium. The first recovery facility 120 is connected to the thermal energy recovery device 100 in a working medium flow path from the expander 113 to the condenser 114. The connection part where the first recovery equipment 120 is connected to the thermal energy recovery device 100 is indicated by "point C1" in FIG. The second recovery facility 130 is connected to the thermal energy recovery device 100 in a working medium flow path from the condenser 114 to the pump 111 and a working medium flow path from the expander 113 to the condenser 114. The connection point on the flow path of the working medium from the condenser 114 to the pump 111 is indicated by "point C2" in FIG. The connection point on the flow path of the working medium from the expander 113 to the condenser 114 is indicated by "point C3" in FIG. The first recovery equipment 120 and the second recovery equipment 130 may be attached to the thermal energy recovery device 100 after the working medium leaks, or may be attached to the thermal energy recovery device 100 in advance. The first recovery facility 120 and the second recovery facility 130 are described below.

  The first recovery facility 120 includes a pipe 125 configured to branch from the working medium circulation path 116 in the thermal energy recovery device 100 at a point C1, a vacuum device 121, a compressor 122, and a heat generator arranged on the pipe 125. It includes an exchanger 123 and a first tank 124. The vacuum device 121 is arranged most upstream in the flow direction of the first medium component among the vacuum device 121, the compressor 122, the heat exchanger 123, and the first tank 124, while the first tank 124 has Is located at the most downstream. The compressor 122 is arranged downstream of the vacuum device 121. The heat exchanger 123 is arranged between the compressor 122 and the first tank 124.

  The vacuum device 121 is provided to create a pressure environment in which the first medium component is selectively vaporized in the space between the vacuum device 121 and the liquid-phase working medium in the thermal energy recovery device 100. The first medium component is vaporized under the pressure environment created by the vacuum device 121 and is sucked by the vacuum device 121. The first medium component then flows from the vacuum device 121 to the compressor 122.

  The compressor 122 is used to reduce the volume of the first medium component vaporized by the vacuum device 121. The first medium component vaporized by the vacuum device 121 is sucked by the compressor 122. The compressor 122 compresses the vaporized first medium component and reduces the volume of the first medium component. The compressed first medium component flows from the compressor 122 into the heat exchanger 123.

  The heat exchanger 123 is used to liquefy the first medium component compressed by the compressor 122. The heat exchanger 123 is configured to exchange heat between the first medium component and the cooling water. The first medium component is cooled by the cooling water in the heat exchanger 123 and becomes a liquid phase. The liquid-phase first medium component flows into the first tank 124 and is stored in the first tank 124.

  After the first medium component in the working medium is recovered in the first tank 124, the second recovery facility 130 is used for recovering the second medium component.

  The second recovery facility 130 has a pipe 134 forming a flow path connected to the circulation path 116 of the thermal energy recovery device 100 at points C2 and C3, a pump 131 arranged on the pipe 134, and a second tank. 132 and the valve body 133. The pump 131 is arranged so as to suck the second medium component from the point C2. The second tank 132 is arranged downstream of the pump 131 in the flow direction of the second medium component. The second medium component sucked by the pump 131 is stored in the second tank 132. The section of the pipe 134 between the second tank 132 and the point C2 guides the gas extruded from the second tank 132 by the inflow of the second medium component into the second tank 132 to the circulation path 116 of the thermal energy recovery device 100. It is used to The valve body 133 is arranged in the section of the pipe 134 between the second tank 132 and the point C2. The valve body 133 is opened during the collection of the second medium component, while being closed for the other periods.

  The method of recovering the first medium component and the second medium component is described below.

  The recovery of the first medium component and the second medium component is executed when the working medium leaks from the thermal energy recovery device 100. When the working medium leaks from the heat energy recovery device 100, the heat energy recovery device 100 is stopped and the leaked portion is repaired. After the repair, the heat energy recovery device 100 is operated so as to obtain the liquid phase state of the working medium. For example, the flow of the heating medium into the evaporator 112 is stopped. In addition, the valve body 141 is opened, and the upstream portion of the expander 113 communicates with the downstream portion through the bypass 140. After that, the pump 111 is driven and the working medium is circulated. Since the evaporation function of the evaporator 112 is lost while the working medium is circulated, the working medium in the heat energy recovery device 100 is entirely in the liquid phase. After the liquid-phase working medium is obtained, the circulation of the working medium is stopped. Then, the selective recovery of the first medium component in the working medium is started.

  In order to selectively recover the first medium component, the vacuum device 121 decompresses the space formed between the vacuum device 121 and the liquid-phase working medium to create a predetermined pressure environment. The space decompressed by the vacuum device 121 is referred to as a “decompression space” in the following description. The initial pressure set at the beginning of the recovery of the first medium component to create a reduced pressure environment is shown in FIG. 2 by the symbol "V1". The initial pressure "V1" is a value that is higher than the saturated vapor pressure of the first medium component and lower than the saturated vapor pressure of the second medium component. When the pressure in the decompression space is set to the initial pressure "V1", the first medium component is mainly vaporized. The vaporized first medium component passes through the vacuum device 121 and is compressed by the compressor 122. The compressed first medium component then becomes a liquid phase in the heat exchanger 123. The liquid-phase first medium component flows into the first tank 124 and is stored in the first tank 124.

  While the first medium component is collected in the first tank 124, the pressure in the decompression space gradually decreases from the initial pressure “V1”. The threshold pressure set to a value smaller than the initial pressure "V1" is shown in FIG. 2 by the symbol "V2". The threshold pressure “V2” is set so that a state in which most of the first medium component is separated from the working medium can be obtained when the pressure in the depressurized space drops to the threshold pressure “V2”.

  When the pressure in the depressurized space drops to the threshold pressure “V2”, the vacuum device 121 stops. When the pressure in the depressurized space is reduced to the threshold pressure “V2”, most of the first medium component is separated from the working medium and stored in the first tank 124. Therefore, the working medium (that is, the liquid-phase second medium component) in which the first medium component is almost removed remains in the thermal energy recovery device 100. The recovery process for the first medium component is switched to the recovery process for the second medium component in the liquid phase when the pressure in the depressurized space reaches the threshold pressure “V2”.

  The pump 131 is started and the valve body 133 is opened for the recovery process of the second medium component in the liquid phase. The pump 131 sucks the liquid-phase second medium component through the point C2 and sends the sucked second medium component to the second tank 132. At this time, the gas in the second tank 132 is pushed out by the inflow of the second medium component in the liquid phase. The gas in the second tank 132 flows from the point C3 into the circulation path 116 of the thermal energy recovery device 100 through the valve body 133. A liquid-phase second medium component is stored in the second tank 132.

  The second medium component is stored in the second tank 132, while the first medium component is stored in the first tank 124. Therefore, it becomes possible to individually measure the collected first medium component and second medium component, and the leakage amount of the first medium component and the second medium component can be known. The recovered first medium component is then replenished with a leakage amount of the first medium component. Similarly, the leaked amount of the second medium component is replenished to the recovered second medium component. The replenished first medium component and second medium component are mixed to create a new working medium. The mixing ratio of the first medium component and the second medium component in the new working medium is the mixing ratio of the first medium component and the second medium component in the working medium that was circulated in the heat energy recovery device 100 before the leakage. Is approximately equal to. Therefore, the new working medium can be reused as the heat energy recovery medium in the heat energy recovery device 100.

  A schematic block diagram showing an exemplary functional configuration of the control system 200 for controlling the above-mentioned recovery operation of recovering the second medium component after selectively recovering the first medium component from the working medium is shown in FIG. .. The control system 200 is described with reference to FIGS.

  The control system 200 is configured to control the vacuum device 121 of the first recovery facility 120, the pump 131 and the valve body 133 of the second recovery facility 130 based on the temperature of the working medium and the state of the pressure environment of the decompression space. .. The control system 200 includes a temperature detection unit 210 that detects the temperature of the working medium, a pressure detection unit 220 that detects the pressure of the working medium, and a control unit 230 that controls the vacuum device 121, the pump 131, and the valve body 133.

  The temperature detector 210 is attached to the heat energy recovery device 100 so as to detect the temperature of the working medium in the heat energy recovery device 100. For example, the temperature detection unit 210 may be attached to the circulation path 116 in the flow section between the expander 113 and the condenser 114. The temperature detection unit 210 is configured to generate a detection signal representing the detected temperature.

  The temperature detector 210 is used to detect the temperature of the working medium, while the pressure detector 220 is used to detect the pressure in the decompression space.

  The pressure detection unit 220 is attached to the thermal energy recovery device 100 so as to detect the pressure in the decompression space. The pressure detection unit 220 is configured to generate a detection signal representing the detected pressure. The detection signals generated by the pressure detection unit 220 and the temperature detection unit 210 are used for control by the control unit 230.

  The controller 230 is connected to the pressure detector 220 and the temperature detector 210 so as to receive the detection signals generated by the pressure detector 220 and the temperature detector 210. The control unit 230 is configured to control the vacuum device 121, the pump 131, and the valve body 133 based on these detection signals. The control unit 230 includes an operation unit 231, a pressure setting unit 232, a first drive unit 233, a second drive unit 234, and a determination unit 235.

  The operation unit 231 is operated by an operator at the start and end of the working medium recovery operation. The operation unit 231 is configured to generate and output a signal according to the operation of the operator. When the worker operates the operation unit 231 so as to instruct the start of the recovery work, the operation unit 231 generates a start request signal for transmitting a request for the start instruction of the worker. When the worker operates the operation unit 231 so as to instruct the end of the collecting work, the operation unit 231 generates an end request signal for transmitting a request for the end instruction of the worker. The end request signal is output to the second drive unit 234, while the start request signal is output to the pressure setting unit 232.

  The pressure setting unit 232 is configured to receive the start request signal and the detection signal from the temperature detection unit 210, which are generated according to the operation of the operator. After receiving the start request signal, the pressure setting unit 232 is configured to determine the initial pressure “V1” and the threshold pressure “V2” according to the temperature represented by the detection signal from the temperature detection unit 210.

  The pressure setting unit 232 includes an initial pressure setting unit 236 and a threshold value setting unit 237 as parts for setting the initial pressure “V1” and the threshold pressure “V2”, respectively. The threshold setting unit 237 is configured to set the threshold pressure “V2” based on the temperature represented by the detection signal from the temperature detecting unit 210. The threshold setting unit 237 is configured such that the information indicating the threshold pressure “V2” is transmitted from the threshold setting unit 237 to the initial pressure setting unit 236 and the determination unit 235. The initial pressure setting unit 236 is configured to set the initial pressure “V1” based on the threshold pressure “V2” and the temperature represented by the detection signal from the temperature detection unit 210. The initial pressure setting unit 236 is configured such that information indicating the initial pressure “V1” is output from the initial pressure setting unit 236 to the first drive unit 233.

  The first driver 233 is configured to receive the detection signal generated by the pressure detector 220, in addition to the information indicating the initial pressure “V1”. The first drive unit 233 is configured to drive the vacuum device 121 so as to obtain the initial pressure “V1” by referring to the pressure represented by the detection signal from the pressure detection unit 220. The first drive unit 233 is configured to operate the vacuum device 121 in a steady state when the pressure in the depressurized space drops to the initial pressure “V1”.

  Since the first medium component is selectively vaporized during the steady operation of the vacuum device 121, the pressure represented by the detection signal generated by the pressure detection unit 220 gradually decreases. The detection signal generated by the pressure detection unit 220 is output not only to the first drive unit 233 but also to the determination unit 235.

  The determination unit 235 is configured to receive the information indicating the threshold pressure “V2” from the threshold setting unit 237 in addition to the detection signal from the pressure detection unit 220. The determination unit 235 is configured to instruct the second drive unit 234 to drive the pump 131 and the valve body 133 when the pressure represented by the detection signal from the pressure detection unit 220 decreases to the threshold pressure “V2”. ..

  The second drive unit 234 is configured to receive the end request signal from the operation unit 231 in addition to the drive instruction of the determination unit 235. The second drive unit 234 includes a pump drive unit 238 provided corresponding to the pump 131, and a valve drive unit 239 provided corresponding to the valve body 133. The pump drive unit 238 is configured to drive and stop the pump 131 according to a drive instruction from the determination unit 235 and an end request signal from the operation unit 231. The valve drive unit 239 is configured to open or close the valve body 133 according to a drive instruction from the determination unit 235 and an end request signal from the operation unit 231.

  A control operation of the control unit 230 which is started in response to an operation on the operation unit 231 will be described with reference to FIGS. 1 to 4. FIG. 4 is a schematic flowchart showing an exemplary control operation of the control unit 230.

(Step S205)
The control unit 230 waits for the operator to operate the operation unit 231. During this time, the worker is repairing the leaked portion and performing operations for obtaining the working medium in the liquid phase. When these operations are completed, the operator operates the operation unit 231 to instruct the control unit 230 to start the collection of the working medium. When the operator operates the operation unit 231 to instruct to start the collection of the working medium, the operation unit 231 generates a start request signal. When the start request signal is output from the operation unit 231 to the pressure setting unit 232, step S210 is executed.

(Step S210)
The threshold setting unit 237 of the pressure setting unit 232 waits for a detection signal from the temperature detection unit 210. When the detection signal is output from the temperature detection unit 210 to the threshold value setting unit 237, step S215 is executed.

(Step S215)
The threshold setting unit 237 finds the saturated vapor pressures (saturated vapor pressures corresponding to the detected temperatures) of the first medium component and the second medium component based on the temperature represented by the detection signal from the temperature detection unit 210. .. The threshold setting unit 237 sets the threshold pressure "V2" to a value lower than the intermediate value between the high pressure and the low pressure of the Rankine cycle based on the found saturated vapor pressures of the first medium component and the second medium component. Information indicating the threshold pressure “V2” is output from the threshold setting unit 237 to the initial pressure setting unit 236 and the determination unit 235. In addition to the information indicating the threshold pressure “V2”, the information indicating the saturated vapor pressure of the second medium component is also transmitted from the threshold setting unit 237 to the initial pressure setting unit 236. When the information indicating the threshold pressure “V2” and the saturated vapor pressure of the second medium component is output from the threshold setting unit 237 to the initial pressure setting unit 236, step S220 is executed.

(Step S220)
The initial pressure setting unit 236 sets the initial pressure “V1” to a value that is higher than the threshold pressure “V2” and lower than the saturated vapor pressure of the second medium component. When the information indicating the initial pressure “V1” is output from the initial pressure setting unit 236 to the first drive unit 233, step S225 is executed.

(Step S225)
The first drive unit 233 and the determination unit 235 wait for a detection signal from the pressure detection unit 220. When the first drive unit 233 and the determination unit 235 receive the detection signal from the pressure detection unit 220, steps S230 and S245 are executed.

(Step S230)
The first drive unit 233 adjusts the output of the vacuum device 121 so that the initial pressure “V1” is obtained, and creates a pressure environment of the initial pressure “V1” in the depressurized space. Then, step S235 is executed.

(Step S235)
The first drive unit 233 refers to the detection signal from the pressure detection unit 220 and determines whether the pressure in the depressurized space has reached the initial pressure “V1”. If the first driving unit 233 determines that the pressure represented by the detection signal has not reached the initial pressure “V1”, step S230 is executed. If the first drive unit 233 determines that the pressure represented by the detection signal has reached the initial pressure “V1”, step S240 is executed.

(Step S240)
The first drive unit 233 causes the vacuum device 121 to perform a steady operation with the output adjusted in step S230. During the steady operation of the vacuum device 121, the first medium component is selectively vaporized. The vaporized first medium component passes through a vacuum device 121 and is subsequently compressed by a compressor 122. The compressed first medium component is cooled in the heat exchanger 123 and becomes a liquid phase. The liquid-phase first medium component flows into the first tank 124.

(Step S245)
While the first medium component is being collected in the first tank 124, the pressure in the depressurized space (that is, the pressure represented by the detection signal from the pressure detection unit 220) gradually decreases. The first drive unit 233 and the determination unit 235 determine whether the pressure represented by the detection signal from the pressure detection unit 220 has reached the threshold pressure “V2”. The first drive unit 233 and the determination unit 235 wait for the pressure represented by the detection signal from the pressure detection unit 220 to reach the threshold pressure “V2”. When the pressure represented by the detection signal from the pressure detection unit 220 reaches the threshold pressure “V2”, most of the first medium component is recovered in the first tank 124, and the thermal energy recovery device 100 is in the liquid phase. The second medium component of is mainly remained. The determination unit 235 generates a drive instruction for driving the second recovery facility 130 to recover the liquid-phase second medium component remaining in the thermal energy recovery device 100. When the drive instruction is output from the determination unit 235 to the second drive unit 234, step S250 is executed.

(Step S250)
When the drive instruction is output from the determination unit 235 to the second drive unit 234, the recovery process of the first medium component is switched to the recovery process of the second medium component. In order to switch the recovery process, the first drive unit 233 stops the vacuum device 121 substantially in synchronization with the output of the drive instruction from the determination unit 235 to the second drive unit 234. The pump drive unit 238 and the valve drive unit 239 of the second drive unit 234 drive the pump 131 of the second recovery facility 130 and open the valve body 133 of the second recovery facility 130 according to the drive instruction from the determination unit 235. When the second drive unit 234 drives the pump 131 and opens the valve body 133, the second medium component remaining in the thermal energy recovery device 100 in the liquid phase flows into the second tank 132. When the collection of the second medium component into the second tank 132 is started, step S255 is executed.

(Step S255)
After starting the collection of the second medium component into the second tank 132, the second drive unit 234 waits for the reception of the end request signal. The end request signal is output from the operation unit 231 to the second drive unit 234 when the operator operates the operation unit 231 and requests the control unit 230 to end the collection process. When the end request signal is output from the operation unit 231 to the second drive unit 234, step S260 is executed.

(Step S260)
The pump drive unit 238 and the valve drive unit 239 of the second drive unit 234 stop the pump 131 and close the valve body 133 in response to the end request signal, and the collection process of the working medium is completed.

  After the recovery process of the working medium, the first medium component and the second medium component in the first tank 124 and the second tank 132 are individually weighed. As a result, it is known how much each of the first medium component and the second medium component leaked. The leaked amount of the first medium component is replenished in the first tank 124. Similarly, the leaked second medium component is replenished in the second tank 132. After replenishing them, the first medium component in the first tank 124 is mixed with the second medium component in the second tank 132 to generate a new working medium. The mixing ratio of the first medium component and the second medium component in the new working medium is substantially equal to the mixing ratio of the first medium component and the second medium component in the working medium used before the leakage. Therefore, the new working medium is preferably reused as the heat energy recovery medium circulated in the heat energy recovery device 100.

  The bypass 140 is preferably used for the recovery of the first medium component. When the valve body 141 on the detour 140 is closed, the influence of the pressure environment set by the vacuum device 121 is stopped by the expander 113 in the stopped state. That is, the working medium existing between the expander 113 and the evaporator 112 is not exposed to the pressure environment set by the vacuum device 121. On the other hand, when the valve body 141 on the detour 140 is opened, the working medium existing between the expander 113 and the evaporator 112 can be exposed to the pressure environment set by the vacuum device 121 as described below. become.

  At the start of collecting the first medium component, the working medium in the liquid phase around the point C1 is exposed to the pressure environment set by the vacuum device 121. As a result, the first medium component is selectively vaporized from the liquid-phase working medium around the point C1. Since the vaporized first medium component is recovered by the first recovery facility 120, the depressurized space between the vacuum device 121 and the liquid-phase working medium gradually expands. When the first medium component is recovered to some extent, the depressurized space can reach the flow path section between the expander 113 and the evaporator 112 through the bypass 140. As a result, the working medium existing in the flow path section between the expander 113 and the evaporator 112 is exposed to the pressure environment set by the vacuum device 121, and the first medium component in the working medium is selectively vaporized. can do. The vaporized first medium component reaches the point C1 through the bypass 140 and is recovered by the first recovery facility 120.

  Since the first recovery facility 120 uses the compressor 122 and the heat exchanger 123 to compress and liquefy the first medium component, the volume of the first medium component is significantly reduced as compared with the gas phase medium component. Therefore, the capacity of the first tank 124 used for storing the first medium component does not have to be excessively large.

  Like the first medium component, the second medium component is recovered in the liquid phase. Therefore, the capacity of the second tank 132 provided for storing the second medium component does not have to be excessively large. Unlike the first medium component, the second medium component is recovered without forming a gas phase, so that the recovery of the second medium component is completed in a short time.

  It should be understood that the embodiments disclosed this time are illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

  Regarding the recovery of the second medium component, the second recovery facility 130 is provided differently from the first recovery facility 120 in the above-described embodiment. However, the vacuum device 121, the compressor 122, and the heat exchanger 123 of the first recovery facility 120 may be used to recover the second medium component. In this case, the second tank 132 for storing the second medium component is replaced with the first tank 124 after collecting the first medium component. After the recovery of the first medium component, the vacuum device 121 creates a pressure environment having a pressure higher than the saturated vapor pressure of the second medium component in the decompression space. As a result, the second medium component is vaporized and flows into the compressor 122 through the vacuum device 121. The second medium component is compressed by the compressor 122 and then cooled by the heat exchanger 123 to become a liquid phase. The liquid-phase second medium component flows into the second tank 132, which is replaced with the first tank 124.

  Regarding the recovery of the first medium component, in the above-described embodiment, the compressor 122 and the heat exchanger 123 are arranged in order to reduce the capacity of the first tank 124. However, the first medium component may be recovered in the first tank 124 without passing through the compressor 122 and the heat exchanger 123. In this case, the first medium component in the vapor phase is stored in the first tank 124.

  Regarding the composition of the working medium, in the above-described embodiment, a technique for collecting the working medium in which the first medium component and the second medium component are mixed is exemplified. However, the recovery techniques described above may be used to recover a working medium that is mixed with more than three types of media components.

  Regarding the collection position of the working medium, in the above-described embodiment, the first medium component of the working medium is collected from the point C1 set in the section between the expander 113 and the condenser 114. However, the first medium component may be recovered from another section where the liquid-phase working medium is present. A first recovery facility 120 connected to the circulation path 116 of the thermal energy recovery system 100 in the section between the condenser 114 and the pump 111 is schematically shown in FIG. Since the working medium in the section between the condenser 114 and the pump 111 is in the liquid phase, no operation is required to bring the working medium into the liquid phase throughout the heat energy recovery device 100. In this case, the temperature detection unit 210 is attached to the thermal energy recovery device 100 so as to detect the temperature of the working medium in the section between the condenser 114 and the pump 111.

  In the above-described embodiment, the second medium component of the working medium is collected from the point C2 set in the section between the condenser 114 and the pump 111. However, the recovery position of the second medium component may be set to another part in the circulation path 116 of the working medium (a part where the second medium component in the liquid phase remains after the selective recovery of the first medium component). Good.

  Regarding the number of recovery positions provided, one recovery position is set for each of the first medium component and the second medium component in the above-described embodiment. However, a plurality of recovery positions may be set for at least one of the first medium component and the second medium component. As a result of setting many collecting positions, the working medium collecting operation is completed in a short time.

  The principles of the above-described embodiments are preferably utilized in various technical fields where it is necessary to recover thermal energy under a Rankine cycle.

100 Thermal energy recovery device 113 Expander 121・ ・ ・ ・ Vacuum device 125 ・ ・ ・ ・ ・ ・ Pipe 140 ・ ・ ・ ・ ・ ・

Claims (7)

Heat energy recovery for recovering heat energy by circulating a non-azeotropic mixed medium in which a first medium component and a second medium component having a higher saturated vapor pressure than the first medium component are mixed as a working medium under Rankine cycle A recovery method for recovering the working medium from an apparatus, comprising:
Creating a pressure environment below the saturated vapor pressure of the second medium component and above the saturated vapor pressure of the first medium component to selectively vaporize the first medium component in the working medium in the liquid phase Recovering the vaporized first medium component;
Recovering the second medium component remaining in the thermal energy recovery device after the selective recovery of the first medium component. Selectively recovering the first medium component comprises:
(I) measuring the temperature of the working medium,
(Ii) creating the pressure environment above the saturated vapor pressure of the first medium component corresponding to the measured temperature and below the saturated vapor pressure of the second medium component corresponding to the measured temperature. The collecting method according to claim 1, comprising: Selectively recovering the first medium component includes reducing a pressure in a pipe connected from the thermal energy recovery device to the vacuum device by using a vacuum device to create the pressure environment. The collection method described in. Selectively recovering the first medium component comprises:
(I) sucking the vaporized first medium component using the vacuum device;
(Ii) compressing the aspirated first medium component;
(Iii) cooling and liquefying the compressed first medium component;
(Iv) storing the liquefied first medium component. The recovery method according to any one of claims 1 to 4, wherein recovering the second medium component includes recovering the second medium component while maintaining a liquid phase of the second medium component. Selectively recovering the first medium component includes stopping the Rankine cycle, and between the upstream portion and the downstream portion of the expander through a bypass that bypasses the expander that is responsible for the expansion process of the Rankine cycle. Allowing the flow of the first medium component in the method according to any one of claims 1 to 5. The recovery method according to claim 1, further comprising measuring the recovered first medium component and the recovered second medium component.