JP7209669B2 - Working medium recovery method and working medium recovery device - Google Patents

Description

The present invention relates to a working medium recovery method and a working medium recovery apparatus for converting a gaseous working medium used in a heat recovery device using a Rankine cycle into a liquid working medium and recovering it in a cylinder.

A heat recovery device that recovers heat from a heat source using a Rankine cycle is known (see Patent Document 1). The heat recovery device includes a working medium pump that discharges a working medium, a circulation channel that is connected to the discharge port and the suction port of the working medium pump, and an evaporator, an expander, a condenser, and a receiver that are arranged in the circulation channel. and have The working medium sent out from the working medium pump sequentially passes through the evaporator, expander, condenser and receiver, and returns to the working medium pump. The heat of the heat source is recovered by the working medium in the evaporator.

JP 2016-56689 A

In the heat recovery device as described above, during maintenance of the heat recovery device, the gaseous working medium in the heat recovery device is liquefied and recovered in a predetermined recovery cylinder. When the liquid working medium accumulates in the recovery cylinder during recovery of the working medium, the pressure in the recovery cylinder rises, so there is a problem that it becomes difficult to recover the gaseous working medium into the recovery cylinder.

Accordingly, the present invention has been made based on the above problems, and an object of the present invention is to recover a working medium capable of suppressing difficulty in recovering a gaseous working medium in a heat recovery device into a recovery cylinder. It is to provide a method and a working medium recovery device.

In the working medium recovery method according to the present invention, a gaseous working medium in a heat recovery device using a Rankine cycle is converted into a liquid working medium through a recovery passage connecting the heat recovery device and a recovery cylinder, and the working medium is returned to the recovery cylinder. a recovery step of recovering, and when the pressure in the recovery cylinder or a pressure corresponding thereto exceeds a threshold value during the recovery step , the gaseous working medium in the recovery cylinder is removed from the recovery cylinder. a reflux step of refluxing to the heat recovery device or the recovery channel through a reflux channel connecting the cylinder and the heat recovery device or the recovery channel, wherein the reflux step is performed by reducing the pressure in the recovery cylinder or is terminated when the pressure corresponding to is equal to or lower than the preset threshold value .

According to the present invention, the gaseous working medium in the heat recovery device using the Rankine cycle is converted into a liquid working medium through the recovery channel connecting the heat recovery device and the recovery cylinder and recovered in the recovery cylinder. A larger amount of the gaseous working medium in the heat recovery device can be recovered in the recovery cylinder as compared with the case where the working medium in the form of gas is recovered in the recovery cylinder. Part of the liquid working medium recovered in the recovery cylinder is gasified by heat input from the outside. Therefore, when the liquid working medium accumulates in the recovery cylinder, the pressure inside the recovery cylinder rises. However, when the pressure in the recovery cylinder or the pressure corresponding thereto exceeds a threshold value, the gaseous working medium in the recovery cylinder is returned to the heat recovery device or the recovery channel through the reflux channel. Excessive increase in internal pressure can be suppressed. Therefore, it is possible to prevent the gaseous working medium in the heat recovery device from being difficult to recover into the recovery cylinder.

In the above configuration, a manual valve may be provided in the reflux flow path. In the reflux step, the manual valve may be opened when the pressure in the collection cylinder or a pressure equivalent thereto exceeds a threshold value.

According to this configuration, when the pressure in the recovery cylinder or the pressure equivalent to it exceeds the threshold value, the operator opens the manual valve to cause the gaseous working medium in the recovery cylinder to return to the reflux flow. It can be returned to a heat recovery device or recovery channel through a passage.

In the above configuration, a relief valve may be provided in the reflux flow path. In the reflux step, even if the relief valve is opened when the differential pressure across the relief valve becomes larger than a set value due to the pressure in the recovery cylinder or the pressure equivalent thereto exceeding a threshold value. good.

According to this configuration, the relief valve is opened when the differential pressure across the relief valve becomes larger than the set value due to the pressure in the recovery cylinder or the pressure equivalent thereto exceeding the threshold value. The gaseous working medium therein is returned to the heat recovery device or recovery channel through the reflux channel.

In the above configuration, a pressure regulating valve may be provided in the reflux flow path. Pressure acquisition means may be provided for acquiring the pressure in the recovery cylinder or a pressure equivalent thereto. In the reflux step, when the pressure acquired by the pressure acquisition means exceeds a threshold, the opening of the pressure regulating valve may be adjusted so that the pressure becomes equal to or less than the threshold.

According to this configuration, when the pressure acquired by the pressure acquisition means exceeds the threshold, the opening of the pressure regulating valve is adjusted so that the pressure becomes equal to or less than the threshold. Excessive rise of the pressure corresponding to is suppressed.

In the above configuration, in the recovery step, a recovery header connected to a plurality of recovery cylinders may be used as the recovery channel to recover the liquid working medium into the plurality of recovery cylinders. In the reflux step, a reflux header connected to a plurality of recovery cylinders may be used as the reflux flow path, and the gaseous working medium in the plurality of recovery cylinders may be refluxed to the heat recovery device or the recovery flow path. .

According to this configuration, in the recovery process, the liquid working medium is recovered in the plurality of recovery cylinders by using the recovery header connected to the plurality of recovery cylinders as the recovery flow path, so that the gaseous working medium in the heat recovery device can be simultaneously recovered into a plurality of recovery cylinders through the recovery channel. Furthermore, in the reflux step, the gaseous working medium in the plurality of recovery cylinders is refluxed to the heat recovery device or the recovery flow path using a reflux header connected to the plurality of recovery cylinders as a reflux flow path. The gaseous working medium therein can be simultaneously returned to the heat recovery device or recovery channel through the reflux channel. Therefore, it is possible to simultaneously suppress an excessive increase in pressure in the plurality of recovery cylinders, thereby simultaneously suppressing difficulty in recovering the gaseous working medium in the heat recovery device into the plurality of recovery cylinders. In addition, more gaseous working medium in the heat recovery device can be recovered in a plurality of recovery cylinders in a short time.

In the above configuration, a recovery channel for recovering the gaseous working medium in the heat recovery device to the recovery cylinder, and a gaseous working medium in the recovery cylinder is returned to the heat recovery device or the recovery channel. A closed circuit may be formed by the reflux channel and the recovery cylinder. Before the recovery step, the closed circuit may be evacuated by a compressor provided in the recovery channel.

According to this configuration, since the closed circuit is evacuated by the compressor provided in the recovery flow path before the recovery process, the air in the closed circuit is prevented from accumulating in the recovery cylinder during the recovery process. can be suppressed. Furthermore, since the gaseous working medium in the recovery passage can be delivered to the recovery cylinder using the compressor, there is no need to prepare a compressor separate from the recovery compressor.

A working medium recovery device according to the present invention is a working medium recovery device used in the above working medium recovery method. The working medium recovery device includes a recovery cylinder, a recovery channel capable of connecting a gas region in which a gaseous working medium exists in a heat recovery device using a Rankine cycle, and the recovery cylinder, and a recovery channel provided in the recovery channel. a compressor for sending out the gaseous working medium in the recovery passageway toward the recovery cylinder; and a gaseous working medium provided in the recovery passageway and delivered toward the recovery cylinder by the compressor. a liquefaction device for condensing a medium; a reflux passage capable of connecting the upstream side of the compressor in the gas region or the recovery passage to the recovery cylinder; a manual valve provided in the reflux passage; a pressure gauge for measuring the pressure in the recovery cylinder or an equivalent pressure.

According to the present invention, the gaseous working medium in the heat recovery device using the Rankine cycle is converted into the liquid working medium by the liquefying device and recovered in the recovery cylinder. More of the gaseous working medium in the heat recovery system can be recovered in the recovery cylinder compared to . Part of the liquid working medium recovered in the recovery cylinder is gasified by heat input from the outside. Therefore, when the liquid working medium accumulates in the recovery cylinder, the pressure inside the recovery cylinder rises. However, the operator can open the manual valve when the pressure measured by the pressure gauge or its equivalent exceeds a threshold value, thereby heating the gaseous working medium in the recovery cylinder. It is possible to prevent the pressure in the recovery bomb from excessively increasing by recirculating it to the recovery device or the recovery channel. For this reason, it is possible to prevent an excessive load from being applied to the compressor, and it is possible to prevent difficulty in recovering the gaseous working medium in the heat recovery device into the recovery cylinder.

A working medium recovery device according to the present invention is a working medium recovery device used in the above working medium recovery method. The working medium recovery device includes a recovery cylinder, a recovery channel capable of connecting a gas region in which a gaseous working medium exists in a heat recovery device using a Rankine cycle, and the recovery cylinder, and a recovery channel provided in the recovery channel. a compressor for sending out the gaseous working medium in the recovery passageway toward the recovery cylinder; and a gaseous working medium provided in the recovery passageway and delivered toward the recovery cylinder by the compressor. a liquefying device for condensing a medium; a reflux passage capable of connecting the upstream side of the compressor in the gas region or the recovery passage to the recovery cylinder; a pressure regulating unit that opens the reflux channel when the pressure or a pressure equivalent thereto exceeds a threshold value.

According to the present invention, the gaseous working medium in the heat recovery device using the Rankine cycle is converted into the liquid working medium by the liquefying device and recovered in the recovery cylinder. More of the gaseous working medium in the heat recovery system can be recovered in the recovery cylinder compared to . Part of the liquid working medium recovered in the recovery cylinder is gasified by heat input from the outside. Therefore, when the liquid working medium accumulates in the recovery cylinder, the pressure inside the recovery cylinder rises. However, since the pressure adjustment unit is provided in the reflux channel and opens the reflux channel when the pressure in the recovery cylinder or the pressure equivalent thereto exceeds a threshold value, the pressure in the recovery cylinder does not rise excessively. is suppressed. Therefore, the compressor is prevented from being subjected to an excessive load, and the gaseous working medium in the heat recovery device is prevented from being difficult to be recovered into the recovery cylinder.

According to the present invention, it is possible to prevent the gaseous working medium in the heat recovery device from being difficult to recover into the recovery cylinder.

FIG. 2 is a diagram showing a usage state of a working medium recovery device used in the working medium recovery method according to the first embodiment of the present invention; 4 is a flow chart showing the processing flow of a preparation step in the working medium recovery method according to the first embodiment of the present invention. 4 is a flow chart showing the process flow of the recovery step in the working medium recovery method according to the first embodiment of the present invention. 4 is a flow chart showing the process flow of the reflux step in the working medium recovery method according to the first embodiment of the present invention. FIG. 5 is a diagram showing a usage state of a first modification of the working medium recovery device used in the working medium recovery method according to the first embodiment of the present invention; FIG. 5 is a diagram showing a usage state of a second modification of the working medium recovery device used in the working medium recovery method according to the first embodiment of the present invention; FIG. 10 is a diagram showing a usage state of a working medium recovery device used in a working medium recovery method according to a second embodiment of the present invention; FIG. 9 is a flow chart showing the process flow of the reflux step in the working medium recovery method according to the second embodiment of the present invention; FIG. FIG. 10 is a diagram showing a usage state of a working medium recovery device used in a working medium recovery method according to a third embodiment of the present invention; FIG. 10 is a flow chart showing the process flow of a recycling step of a working medium recovery method according to a third embodiment of the present invention; FIG.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. However, for convenience of explanation, the drawings referred to below are necessary for explaining the working medium recovery method according to each embodiment of the present invention and the working medium recovery device used in the working medium recovery method. It is a simplified representation of the main components. Therefore, the working medium recovery method and working medium recovery device according to each embodiment of the present invention may include optional components not shown in each drawing referred to in this specification.

(First embodiment)
Hereinafter, a working medium recovery method and a working medium recovery device according to a first embodiment of the present invention will be described with reference to FIG.

The working medium recovery device 1 is connected to the heat recovery device 10 when maintenance is performed on the heat recovery device 10 that utilizes heat such as exhaust heat for power generation using the Rankine cycle of the working medium. The gaseous working medium is liquefied and recovered in the recovery cylinder 2 . Exhaust heat includes supercharged air supplied to marine engines, exhaust heat from engines, exhaust heat from thermal power plants, incineration facilities, factories, and the like.

As shown in FIG. 1, the heat recovery device 10 includes an evaporator 11, an expander 13, a power recovery machine 14, a condenser 15, a working medium pump P, a circulation flow path 17 through which the working medium flows, It has

The evaporator 11 evaporates the working medium by exchanging heat between the working medium flowing through the circulation flow path 17 and the heating medium.

The expander 13 expands the gaseous working medium evaporated by the evaporator 11 .

The power recovery machine 14 is connected to the expander 13 . The power recovery machine 14 recovers the expansion energy of the gaseous working medium expanding in the expander 13 . As the power recovery device 14, for example, a generator or a compressor that is rotationally driven by expansion energy can be used.

The condenser 15 condenses the gaseous working medium by exchanging heat between the gaseous working medium flowing out of the expander 13 and a cooling medium (cooling water, air, etc.).

The working medium pump P pressurizes the liquid working medium that has flowed out of the condenser 15 and sends it to the evaporator 11 .

The circulation flow path 17 includes a gas region 17a where the gaseous working medium vaporized by the evaporator 11 exists, and a liquefaction region 17b where the liquid working medium condensed by the condenser 15 exists. The gas region 17a extends from the evaporator 11 to the condenser 15 in the working medium flow direction. The liquefaction zone 17b extends from the condenser 15 to the evaporator 11 in the working medium flow direction.

Two device-side connection valves 18 and 19 for connecting the working medium recovery device 1 to the heat recovery device 10 are provided in the circulation flow path 17 in the gas region 17a. In FIG. 1 , two device side connection valves 18 and 19 are connected between the expander 13 and the condenser 15 . The device-side connection valve 18 is configured to be connectable to the recovery passageway 3, which will be described later. The apparatus-side connection valve 19 is configured to be connectable to a recirculation flow path 6, which will be described later.

The working medium recovery device 1 includes a recovery cylinder 2 , a recovery channel 3 and a reflux channel 6 .

The recovery cylinder 2 stores the working medium recovered from the heat recovery device 10 in a liquid state. The recovery cylinder 2 is provided with two cylinder side connection valves 20 and 21 .

The recovery channel 3 connects the circulation channel 17 in the gas region 17a of the heat recovery device 10 and the recovery cylinder 2 to recover the gaseous working medium in the heat recovery device 10 to the recovery cylinder 2. . The recovery flow path 3 is connected to one apparatus side connection valve 18 and one cylinder side connection valve 20 . A cylinder-side recovery pipe 24 extending inside the recovery cylinder 2 is connected to one of the cylinder-side connection valves 20 . The outlet (lower end) of the cylinder-side recovery pipe 24 is located at the bottom inside the recovery cylinder 2 .

A compressor 4 and a liquefying device 5 are provided in the recovery channel 3 . The compressor 4 feeds the gaseous working medium in the recovery channel 3 sucked from the gas region 17 a of the circulation channel 17 toward the recovery cylinder 2 . The liquefying device 5 is provided between the compressor 4 and the recovery cylinder 2 in the recovery channel 3 . The liquefying device 5 condenses the gaseous working medium sent toward the recovery cylinder 2 by the compressor 4 by exchanging heat with a cooling medium (cooling water, air, etc.).

The reflux flow path 6 connects the gas region 17 a of the heat recovery device 10 and the recovery cylinder 2 to return the gaseous working medium in the recovery bomb 2 to the gas region 17 a of the heat recovery device 10 . The reflux flow path 6 is connected to the other device side connection valve 19 and the other cylinder side connection valve 21 . A cylinder-side recirculation pipe 25 extending inside the recovery cylinder 2 is connected to the other cylinder-side connection valve 21 . The inlet (lower end) of the cylinder-side reflux pipe 25 is located at the upper part in the recovery cylinder 2 (see FIG. 1). This makes it easier for the gaseous working medium in the recovery cylinder 2 to flow into the reflux passage 6 .

A manual valve 7 and a pressure gauge 8 are provided in the reflux flow path 6 . The manual valve 7 is configured to be manually opened and closed. A pressure gauge 8 is provided between the manual valve 7 and the recovery cylinder 2 in the reflux passage 6 . The pressure gauge 8 measures the pressure on the recovery cylinder 2 side of the manual valve 7 in the reflux passage 6 , that is, the pressure corresponding to the pressure inside the recovery cylinder 2 . Incidentally, the pressure gauge 8 may measure the pressure inside the recovery cylinder 2 .

A closed circuit forming pipe 9 that connects the recovery channel 3 and the reflux channel 6 is provided on the heat recovery device 10 side of the manual valve 7 and the compressor 4 in the recovery channel 3 and the reflux channel 6 . The closed circuit forming pipe 9 is provided with a closed circuit on-off valve 22 (see FIG. 1). Note that the closed circuit on-off valve 22 may be omitted.

Here, a recovery method for recovering the gaseous working medium in the heat recovery device 10 into the recovery cylinder 2 using the working medium recovery device 1 will be described with reference to FIGS.

First, as an initial state, the recovery channel 3 and the reflux channel 6 in the heat recovery device 10 are not connected to the two device side connection valves 18 and 19 of the heat recovery device 10, respectively, and the two device side connection valves 18 , 19 are set to the closed state. On the other hand, the recovery channel 3 and the reflux channel 6 are connected to two cylinder side connection valves 20 and 21, respectively, and the manual valve 7, the two cylinder side connection valves 20 and 21, and the open/close valve 22 for closed circuit are closed. state is set.

In this initial state, a preparatory step of connecting the working medium recovery device 1 to the heat recovery device 10 is performed (see FIG. 2). In the preparation step, first, the recovery channel 3 is connected to one device-side connection valve 18, and the reflux channel 6 is connected to the other device-side connection valve 19 (step S1). As a result, a closed circuit 23 is formed by the recovery channel 3 , the reflux channel 6 and the recovery cylinder 2 . Next, the manual valve 7, the two cylinder side connection valves 20 and 21, and the closed circuit on-off valve 22 are opened (step S2).

Next, the closed circuit 23 is evacuated by the compressor 4 of the working medium recovery device 1, and the air in the closed circuit 23 is discharged to the outside (step S3). To discharge the air in the closed circuit 23, for example, a discharge valve (not shown) is provided downstream of the compressor 4 in the recovery passage 3, and the discharge valve is opened as the compressor 4 draws a vacuum. can be done by A compressor other than the compressor 4 of the working medium recovery device 1 is connected to the closed circuit 23, and the closed circuit 23 is evacuated by the other compressor to discharge the air in the closed circuit 23 to the outside. may

After the preparation process is finished, a recovery process is performed in which the gaseous working medium in the heat recovery device 10 is converted into a liquid working medium through the recovery passage 3 and recovered in the recovery cylinder 2 .

Specifically, as shown in FIG. 3, in the recovery step, first, the manual valve 7 and the closed circuit opening/closing valve 22 are closed, and the two device side connection valves 18 and 19 are opened (step S4). Next, the working medium pump P of the heat recovery device 10 is driven to circulate the working medium in the circulation flow path 17, and the compressor 4 of the working medium recovery device 1 is driven to flow the cooling medium to the liquefaction device 5 ( step S5). As a result, the liquid working medium in the circulation flow path 17 is vaporized by the evaporator 11 and transferred to the vaporization region 17a, and the gaseous working medium transferred to the vaporization region 17a is transferred from the gas region 17a to the recovery stream. It flows out into path 3 and is delivered by compressor 4 towards recovery cylinder 2 . The gaseous working medium sent toward the recovery cylinder 2 is stored in the recovery cylinder 2 after being condensed by exchanging heat with the cooling medium in the liquefier 5 . Here, since part of the liquid working medium stored in the recovery cylinder 2 is gasified, when the liquid working medium accumulates in the recovery cylinder 2, the pressure in the recovery cylinder 2 gradually increases. .

Finally, when all the working medium in the circulation flow path 17 is recovered in the recovery cylinder 2, the working medium pump P and the compressor 4 are stopped (step S6). This completes the collection process.

It should be noted that the working medium pump P does not have to be driven in step S5 of the recovery process. In this case, the working medium pump P is driven after the compressor 4 is stopped and the recovery process is completed. As a result, the liquid working medium in the circulation flow path 17 is vaporized by the evaporator 11 and transferred to the vaporization region 17a. After that, the working medium pump P is stopped and the compressor 4 is driven to restart the recovery process.

While the recovery process is being performed, the reflux process is performed as appropriate (see FIG. 4). In the reflux process, first, the operator grasps the indicated value I of the pressure gauge 8 and appropriately determines whether or not the indicated value I of the pressure gauge 8 exceeds a preset threshold value T (step S7). When the operator determines in step S7 that the indicated value I of the pressure gauge 8 does not exceed the preset threshold value T (NO), the operator makes the determination in step S7 again after a while. On the other hand, when the operator determines in step S7 that the indicated value I of the pressure gauge 8 exceeds the preset threshold value T (YES), the manual valve 7 is opened (step S8). As a result, the gaseous working medium in the recovery cylinder 2 is recirculated to the heat recovery device 10 through the recirculation passage 6 . By performing the reflux process, the gaseous working medium in the recovery cylinder 2 is refluxed to the heat recovery device 10 through the reflux passage 6, and the pressure in the recovery cylinder 2 is reduced. Incidentally, the threshold value T is appropriately set according to the pressure resistance capability of the recovery cylinder 2, the capability of the compressor 4, and the like.

After the manual valve 7 is opened, the operator appropriately determines whether or not the indicated value I of the pressure gauge 8 has become equal to or less than a preset threshold value T (step S9). When the operator determines in step S9 that the indicated value I of the pressure gauge 8 is not equal to or less than the preset threshold value T (NO), the operator makes the determination in step S9 again after a while. On the other hand, when the operator determines in step S9 that the indicated value I of the pressure gauge 8 has become equal to or less than the preset threshold value T (YES), the operator closes the manual valve 7 (step S10). This completes the reflux process.

The operator may appropriately determine whether or not the indicated value I of the pressure gauge 8 exceeds a preset threshold value T after completing the reflux process. At this time, if it is determined that the indicated value I of the pressure gauge 8 does not exceed the preset threshold value T, the reflux step is not performed. On the other hand, when it is determined that the indicated value I of the pressure gauge 8 exceeds the preset threshold value T, the manual valve 7 is opened again to perform the reflux process. After that, when the operator determines that the indicated value I of the pressure gauge 8 has become equal to or less than the preset threshold value T, the operator closes the manual valve 7 to end the reflux process.

In the recovery process, when the liquid working medium in the recovery cylinder 2 is full, the liquid working medium may be stored in another recovery cylinder 2 . In this case, the compressor 4 of the working medium recovery device 1 is stopped, and the two cylinder side connection valves 20 and 21 and the two device side connection valves 18 and 19 are closed. In this state, the recovery channel 3 and the reflux channel 6 are removed from the two cylinder side connection valves 20 and 21 and connected to the two cylinder side connection valves 20 and 21 of another recovery cylinder 2 . Then, the two device side connection valves 18 and 19 and the two cylinder side connection valves 20 and 21 of the other recovery cylinder 2 are opened, and the compressor 4 of the working medium recovery device 1 is driven to restart the recovery process. .

When ending the recovery process, the two device-side connection valves 18 and 19 are closed, and the two cylinder-side connection valves 20 and 21 are closed. After the two device side connection valves 18, 19 and the two cylinder side connection valves 20, 21 are closed, the recovery flow path 3 and the reflux flow path 6 are connected to the device side connection valves 18, 19 and the cylinder side connection valve 20 , 21.

In the working medium recovery method of the first embodiment, the gaseous working medium in the heat recovery device 10 using the Rankine cycle is converted into a liquid working medium through the recovery channel 3 connecting the heat recovery device 10 and the recovery cylinder 2. Therefore, more gaseous working medium in the heat recovery device 10 can be recovered in the recovery cylinder 2 than in the case where the gaseous working medium is recovered in the recovery cylinder 2. . Part of the liquid working medium recovered in the recovery cylinder 2 is gasified by heat input from the outside. Therefore, when the liquid working medium accumulates in the recovery cylinder 2, the pressure inside the recovery cylinder 2 increases. However, in the working medium recovery method of the first embodiment, when the pressure in the recovery cylinder 2 exceeds the threshold value, the gaseous working medium in the recovery cylinder 2 is transferred through the reflux passage 6 to the heat recovery device or the recovery stream. Since it is returned to the path 3, the pressure in the recovery cylinder 2 can be suppressed from rising excessively. Therefore, it is possible to prevent the gaseous working medium in the heat recovery device 10 from being difficult to recover into the recovery cylinder 2 .

In the working medium recovery method of the first embodiment, the operator can open the manual valve 7 when the pressure measured by the pressure gauge 8 exceeds the threshold value. It is possible to prevent the pressure in the recovery cylinder 2 from rising excessively by recirculating the working medium in the form of heat to the heat recovery device. Therefore, it is possible to prevent an excessive load from being applied to the compressor 4 , and it is possible to prevent the gaseous working medium in the heat recovery device 10 from being difficult to be recovered into the recovery cylinder 2 .

(Modified example of the first embodiment)
Modifications of the working medium recovery method and the working medium recovery device 1 of the first embodiment will be described below.

In the working medium recovery device 1 of the first embodiment, the return channel 6 is connected to the circulation channel 17 in the gas region 17a of the heat recovery device 10, but the first modification of the working medium recovery device 1 shown in FIG. In the example, it is connected upstream of the compressor 4 in the recovery passage 3 . In this case, the device side connection valve 19 and the closed circuit opening/closing valve 22 are omitted.

In the preparation step, first, by connecting the recovery channel 3 to the device-side connection valve 18, the recovery channel 3, the reflux channel 6, and the recovery cylinder 2 form a closed circuit 23, and the two cylinder-side connection valves are connected. 20, 21 and manual valve 7 are opened. Next, the closed circuit 23 is evacuated by the compressor 4 of the working medium recovery device 1, and the air in the closed circuit 23 is discharged to the outside.

In the reflux process, the gaseous working medium in the recovery cylinder 2 is refluxed to the upstream side of the compressor 4 in the recovery passage 3 through the reflux passage 6 . Other points are the same as in the reflux step of the first embodiment. Note that the recovery step and the working medium circulation step are the same as those in the first embodiment, so description thereof will be omitted.

In the working medium recovery method of the first embodiment, the gaseous working medium in the heat recovery device 10 is recovered into the recovery cylinders 2 one by one. In this case, in the second modification of the working medium recovery device 1 shown in FIG. a recovery header 3b branching from 3a and connected to a plurality of recovery cylinders 2; The recovery header 3 b is connected to one cylinder side connection valve 20 of each recovery cylinder 2 .

The return flow path 6 includes a device-side return pipe 6a configured to be connectable to the other device-side connection valve 19, and a return header 6b branched from the device-side return pipe 6a and connected to a plurality of recovery cylinders 2. (See Figure 6). The reflux header 6 b is connected to the other cylinder side connection valve 21 of each recovery cylinder 2 .

In the recovery step in the second modified example, the liquid working medium is recovered in a plurality of recovery cylinders 2 using a recovery header 3 b connected to the plurality of recovery cylinders 2 . In the reflux process, the gaseous working medium in the plurality of recovery cylinders 2 is refluxed to the heat recovery device 10 using the reflux header 6 b connected to the plurality of recovery cylinders 2 . Therefore, the gaseous working medium in the heat recovery device 10 can be simultaneously recovered into the plurality of recovery cylinders 2 through the recovery channel 3 . Furthermore, in the reflux process, the gaseous working medium in the plurality of recovery cylinders 2 is refluxed to the heat recovery device 10 using the reflux header 6b connected to the plurality of recovery cylinders 2 as the reflux flow path 6, so that the plurality of recovery The gaseous working medium in the cylinder 2 can be simultaneously returned to the heat recovery device 10 through the reflux channel 6 . As a result, it is possible to suppress an excessive increase in the pressure in the plurality of recovery cylinders 2 at the same time. At the same time, it is possible to suppress and recover more of the gaseous working medium in the heat recovery device 10 in a plurality of recovery cylinders 2 in a short time.

(Second embodiment)
A working medium recovery method and a working medium recovery device according to the second embodiment will be described below with reference to FIG. Elements similar to those of the first embodiment are assigned the same reference numerals as those of the first embodiment, and descriptions thereof are omitted.

In the working medium recovery device 1 of the first embodiment, the manual valve 7 is provided in the recirculation flow path 6, but in the working medium recovery device 31 of the second embodiment, as shown in FIG. A relief valve 32 is provided in the return flow path 6 . Incidentally, the pressure gauge 8 may be omitted.

The relief valve 32 is configured to open when the differential pressure Pa1 across the relief valve 32 becomes greater than the set value K1. The set value K1 is set to the differential pressure across the relief valve 32 when the pressure in the recovery cylinder 2 or a pressure equivalent thereto exceeds a threshold value. The set value K1 is, for example, 0.05 to 0.3 MPa, preferably 0.1 MPa.

Next, a recovery method for recovering the gaseous working medium in the heat recovery device 10 into the recovery cylinder 2 using the working medium recovery device 31 of the second embodiment will be described with reference to FIG. Since the preparation process and the collection process are the same as in the first embodiment, the description of the first embodiment is used.

In the reflux process of the second embodiment, first, when the pressure in the recovery cylinder 2 or the pressure equivalent thereto exceeds a threshold value and the differential pressure Pa1 across the relief valve 32 becomes larger than the set value K1 (step S11). , the relief valve 32 is opened (step S12). Thereby, the gaseous working medium in the recovery cylinder 2 is returned to the heat recovery device 10 through the reflux passage 6 . As a result, the pressure inside the recovery cylinder 2 is lowered. When the differential pressure Pa1 before and after the relief valve 32 becomes equal to or less than the set value K1 due to the pressure drop in the recovery cylinder 2 (step S13), the relief valve 32 is closed (step S14). This completes the reflux process. The relief valve 32 is an example of a pressure regulating section that opens a reflux passage when the pressure in the recovery cylinder 2 or a pressure corresponding thereto exceeds a threshold value.

Also in the working medium recovery method and the working medium recovery device 31 of the second embodiment, a large amount of gaseous working medium in the heat recovery device 10 can be recovered in the recovery cylinder 2 . The relief valve 32 is configured to open when the differential pressure across the relief valve 32 becomes greater than a set value due to the pressure in the recovery cylinder 2 or a pressure equivalent thereto exceeding a threshold value. Therefore, the pressure in the recovery cylinder 2 is suppressed from rising excessively. Therefore, the compressor 4 is prevented from being overloaded, and the gaseous working medium in the heat recovery device 10 is prevented from being difficult to be recovered into the recovery cylinder 2 .

In addition, in the second embodiment, the return flow path 6 may be connected to the upstream side of the compressor 4 in the recovery flow path 3 in the same manner as in the embodiment shown in FIG. Also in the second embodiment, the working medium may be recovered in a plurality of recovery cylinders 2 . In this case, the recovery channel 3 includes a device-side recovery pipe 3a connected to one of the device-side connection valves 18 and a plurality of recovery pipes branched from the device-side recovery pipe 3a, as in the embodiment shown in FIG. and a recovery header 3b connected to the cylinder 2. The return flow path 6 includes a device-side return pipe 6a configured to be connectable to the other device-side connection valve 19, and a device-side return pipe 6a branched from the device-side return pipe 6a. and a reflux header 6 b connected to a plurality of recovery cylinders 2 .

(Third embodiment)
A working medium recovery method and a working medium recovery device 41 according to the third embodiment will be described below with reference to FIG. Elements similar to those of the first embodiment are assigned the same reference numerals as those of the first embodiment, and descriptions thereof are omitted.

In the working medium recovery device 1 of the first embodiment, the return flow path 6 is provided with the manual valve 7 and the pressure gauge 8, but in the working medium recovery device 41 of the third embodiment, as shown in FIG. Instead of the manual valve 7 and the pressure gauge 8 , a pressure regulating valve 43 and a pressure acquiring means 42 for acquiring a pressure corresponding to the pressure inside the recovery cylinder 2 are provided in the reflux flow path 6 as a pressure regulating unit.

Specifically, the pressure acquisition means 42 is a differential pressure gauge, and acquires the differential pressure Pa2 across the pressure regulating valve 43 in the reflux passage 6 . When the pressure acquisition means 42 determines that the acquired differential pressure Pa2 is greater than the set value K2, the pressure acquisition means 42 adjusts the opening of the pressure regulating valve 43 so that the acquired differential pressure Pa2 is equal to or less than the set value K2. to the pressure regulating valve 43 . When the pressure acquisition means 42 determines that the acquired differential pressure Pa2 is equal to or lower than the set value K2, the pressure acquisition means 42 transmits a closing signal for closing the pressure control valve 43 to the pressure control valve 43 . The set value K2 is set to a differential pressure across the pressure regulating valve 43 when the pressure corresponding to the pressure inside the recovery cylinder 2 exceeds the threshold value. The set value K2 is, for example, 0.05 to 0.3 MPa, preferably 0.1 MPa.

Next, a recovery method for recovering the gaseous working medium in the heat recovery device 10 into the recovery cylinder 2 using the working medium recovery device 41 of the third embodiment will be described with reference to FIG. Since the preparation process and the collection process are the same as in the first embodiment, the description of the first embodiment is used.

In the reflux process of the third embodiment, first, the pressure acquiring means 42 determines whether or not the acquired differential pressure Pa2 is greater than the set value K2 (step S21). At this time, when the pressure acquisition means 42 determines in step S21 that the acquired differential pressure Pa2 is equal to or less than the set value K2 (NO), the determination in step S21 is repeated. On the other hand, when the pressure acquisition means 42 determines in step S21 that the acquired differential pressure Pa2 exceeds the set value K2 (YES), it outputs an opening adjustment signal (step S22). When the pressure regulating valve 43 receives the opening degree adjustment signal output from the pressure acquisition means 42, the pressure regulating valve 43 opens the reflux flow path 6 to the opening degree indicated by the opening degree adjustment signal (step S23). As a result, the degree of opening of the pressure regulating valve 43 is adjusted so that the pressure corresponding to the pressure inside the recovery cylinder 2 is equal to or lower than the threshold value. When the pressure regulating valve 43 opens, the gaseous working medium in the recovery cylinder 2 is returned to the heat recovery device 10 through the reflux passage 6, and the pressure in the recovery cylinder 2 decreases.

After that, the pressure acquiring means 42 determines whether or not the acquired differential pressure Pa2 has become equal to or less than the set value K2 (step S24). When the pressure acquiring means 42 determines in step 24 that the acquired differential pressure Pa2 is not equal to or lower than the set value K2 (NO), it repeats the determination in step S24. On the other hand, when the pressure acquiring means 42 determines in step 24 that the acquired differential pressure Pa2 has become equal to or less than the set value K2 (YES), it transmits a close signal to the pressure regulating valve 43 (step S25). Upon receiving the closing signal, the pressure regulating valve 43 closes the reflux passage 6 (step S26). This completes the reflux process. The pressure acquisition means 42 and the pressure regulating valve 43 are an example of a pressure regulating section that opens a reflux passage when the pressure in the recovery cylinder 2 or the pressure corresponding thereto exceeds a threshold value.

Also in the working medium recovery method and the working medium recovery device 41 of the third embodiment, a large amount of gaseous working medium in the heat recovery device 10 can be recovered in the recovery cylinder 2 . Since the pressure regulating valve 43 opens to the degree of opening indicated by the degree of opening regulating signal received from the pressure acquisition means 42, the pressure in the recovery cylinder 2 is prevented from rising excessively. Therefore, the compressor 4 is prevented from being overloaded, and the gaseous working medium in the heat recovery device 10 is prevented from being difficult to be recovered into the recovery cylinder 2 .

In the working medium recovery method and the working medium recovery device 41 of the third embodiment, the pressure acquisition means 42 is configured so that the pressure regulating valve in the reflux passage 6 can acquire the differential pressure across the pressure regulating valve 43 in the reflux passage 6 . 43 (see FIG. 9), it may be connected only downstream of the pressure regulating valve 43 in the reflux passage 6 so that only the pressure corresponding to the pressure in the recovery cylinder 2 can be obtained. Alternatively, the pressure acquisition means 42 may be connected to the recovery cylinder 2 so as to acquire the pressure inside the recovery cylinder 2 .

In this case, when the acquired pressure exceeds the threshold, the pressure acquiring means 42 outputs an opening adjustment signal for adjusting the opening of the pressure regulating valve 43 so that the acquired pressure becomes equal to or less than the threshold. Send to the regulating valve 43 . When the pressure regulating valve 43 receives the opening degree adjustment signal from the pressure acquisition means 42, the pressure regulating valve 43 opens the reflux flow path 6 to the opening degree indicated by the opening degree adjustment signal.

Incidentally, in the third embodiment, the return flow path 6 may be connected to the upstream side of the compressor 4 in the recovery flow path 3 as in the embodiment shown in FIG. In addition, in the second embodiment, as in the embodiment shown in FIG. 3, the recovery channel 3 includes a device-side recovery pipe 3a connected to one of the device-side connection valves 18 and a device-side recovery pipe 3a branched from the device-side recovery pipe 3a. and a recovery header 3b connected to a plurality of recovery cylinders 2, and the return flow path 6 includes a device-side return pipe 6a configured to be connectable to the other device-side connection valve 19, and a device-side return pipe 6a. A reflux header 6b branching from 6a and connected to a plurality of recovery cylinders 2 may also be included.

1 working medium recovery device 2 recovery cylinder 3 recovery channel 3b recovery header 4 compressor 5 liquefaction device 6 reflux channel 6b reflux header 7 manual valve 8 pressure gauge 10 heat recovery device 17a gas region 23 closed circuit 32 relief valve 42 pressure acquisition Means 43 Pressure regulating valve

Claims (8)

a recovery step of converting a gaseous working medium in a heat recovery device using a Rankine cycle into a liquid working medium through a recovery channel connecting the heat recovery device and a recovery cylinder and recovering it in a recovery cylinder;
During the recovery process, when the pressure in the recovery cylinder or the pressure equivalent thereto exceeds a threshold value, the gaseous working medium in the recovery cylinder is transferred to the recovery cylinder and the heat recovery device. or a reflux step of refluxing to the heat recovery device or the recovery channel through a reflux channel connecting with the recovery channel ,
The reflux step ends when the pressure in the collection cylinder or a pressure equivalent thereto becomes equal to or less than the preset threshold value .
Working medium recovery method. A manual valve is provided in the reflux channel,
In the reflux step, the manual valve is opened when the pressure in the recovery cylinder or a pressure equivalent thereto exceeds a threshold value.
The working medium recovery method according to claim 1. A relief valve is provided in the reflux flow path,
In the reflux step, the relief valve opens when the differential pressure across the relief valve becomes greater than a set value due to the pressure in the recovery cylinder or a pressure equivalent thereto exceeding a threshold value.
The working medium recovery method according to claim 1. A pressure regulating valve is provided in the reflux flow path,
A pressure acquisition means for acquiring the pressure in the recovery cylinder or a pressure equivalent thereto is provided,
In the reflux step, when the pressure acquired by the pressure acquisition means exceeds a threshold, the opening of the pressure regulating valve is adjusted so that the pressure becomes equal to or less than the threshold.
The working medium recovery method according to claim 1. In the recovery step, a recovery header connected to a plurality of recovery cylinders is used as the recovery channel to recover the liquid working medium into the plurality of recovery cylinders,
In the reflux step, a reflux header connected to a plurality of recovery cylinders is used as the reflux flow path to reflux the gaseous working medium in the plurality of recovery cylinders to the heat recovery device or the recovery flow path.
The working medium recovery method according to any one of claims 1 to 4. a recovery channel for recovering the gaseous working medium in the heat recovery device to the recovery cylinder; and a reflux channel for returning the gaseous working medium in the recovery cylinder to the heat recovery device or the recovery channel. , forming a closed circuit with the recovery cylinder,
before the recovery step, the closed circuit is evacuated by a compressor provided in the recovery channel;
The working medium recovery method according to any one of claims 1 to 5. A working medium recovery device used in the working medium recovery method according to any one of claims 1 to 6,
a recovery cylinder;
a recovery channel capable of connecting a gas region in which a gaseous working medium exists in a heat recovery device using a Rankine cycle and the recovery cylinder;
a compressor provided in the recovery channel for sending out the gaseous working medium in the recovery channel toward the recovery cylinder;
a liquefying device provided in the recovery passageway for condensing the gaseous working medium sent toward the recovery cylinder by the compressor;
a reflux channel capable of connecting the upstream side of the compressor in the gas region or the recovery channel and the recovery cylinder;
a manual valve provided in the reflux channel;
a pressure gauge that measures the pressure in the recovery cylinder or a pressure equivalent thereto,
Working medium recovery device. A working medium recovery device used in the working medium recovery method according to any one of claims 1 to 6,
a recovery cylinder;
a recovery channel capable of connecting a gas region in which a gaseous working medium exists in a heat recovery device using a Rankine cycle and the recovery cylinder;
a compressor provided in the recovery channel for sending out the gaseous working medium in the recovery channel toward the recovery cylinder;
a liquefying device provided in the recovery passageway for condensing the gaseous working medium sent toward the recovery cylinder by the compressor;
a reflux channel capable of connecting the upstream side of the compressor in the gas region or the recovery channel and the recovery cylinder;
a pressure regulating unit provided in the reflux channel and opening the reflux channel when the pressure in the recovery cylinder or a pressure equivalent thereto exceeds a threshold value;
Working medium recovery device.

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