JP6647922B2 - Thermal energy recovery apparatus and start-up method thereof - Google Patents

Description

  The present invention relates to a thermal energy recovery device and a method for starting the same.

  BACKGROUND ART Conventionally, a thermal energy recovery device that recovers power from a heating medium such as exhaust gas discharged from various facilities in a factory is known. For example, Patent Document 1 discloses an evaporator that heats a working medium by a heating medium supplied from an external heat source, a preheater that heats a working medium before flowing into the evaporator by a heating medium that flows out of the evaporator. An expander for expanding the working medium flowing out of the evaporator, a generator connected to the expander, a condenser for condensing the working medium flowing out of the expander, and a preheater for the working medium condensed in the condenser. A power generation device (thermal energy recovery device) that includes a working medium pump that feeds to a pump and a circulation flow path that connects a preheater, an evaporator, an expander, a condenser and a pump is disclosed.

JP 2014-47632 A

  In the thermal energy recovery device described in Patent Literature 1, when steam (gas phase medium) is supplied to the evaporator as a heating medium, the temperature of the evaporator rises rapidly at the start of operation of the device, thereby causing evaporation. There is a concern that the thermal stress generated in the vessel may increase rapidly. Specifically, before the operation of the apparatus, the temperature of the evaporator is relatively low, while the heat energy of the vapor-phase heating medium such as steam is very large. If a high-temperature gas-phase heating medium flows, the temperature of the evaporator may rise rapidly.

  An object of the present invention is to provide a thermal energy recovery device capable of suppressing a sudden increase in thermal stress generated in an evaporator at the start of operation, and a method of starting the same.

  As means for solving the above problems, the present invention provides an evaporator for evaporating the working medium by exchanging heat between a working medium and a gaseous heating medium supplied from the outside, and a heating medium flowing out of the evaporator. And a preheater that heats the working medium by exchanging heat with the working medium before flowing into the evaporator, an energy recovery unit that recovers energy from the working medium flowing out of the evaporator, the preheater, A circulation path for connecting the evaporator and the energy recovery unit and for flowing the working medium, a pump provided in the circulation path, and heating for supplying the heating medium to the evaporator and the preheater. A medium flow path, a flow rate adjustment unit provided at a portion of the heating medium flow path upstream of the evaporator, and a control unit, wherein the control unit is configured to control a temperature of the evaporator. Until value, in a state in which the pump is stopped, the inflow amount of the gas phase of the heating medium to the evaporator for controlling the flow rate adjuster so as to increase gradually, to provide a thermal energy recovery device.

  In this thermal energy recovery device, the flow rate of the gaseous heating medium (steam, etc.) into the evaporator gradually increases until the temperature of the evaporator reaches the specified value, so that a rapid rise in the temperature of the evaporator is suppressed. Is done. Furthermore, since the pump is stopped until the temperature of the evaporator reaches the specified value, a rapid inflow of the heating medium into the evaporator, that is, a rapid rise in the temperature of the evaporator is more reliably suppressed. Specifically, if the pump is driven before the temperature of the evaporator reaches the specified value, the working medium flows into the evaporator, and the working medium cools the gas-phase heating medium. Condensation of the gas phase heating medium is promoted. When the gaseous heating medium condenses, the volume (pressure) of the heating medium becomes small, so that the inflow of the gaseous heating medium from the heating medium flow path to the evaporator is promoted, whereby the temperature of the evaporator rises sharply. May be. On the other hand, in the present apparatus, the pump is stopped until the temperature of the evaporator reaches the specified value, so that the temperature of the evaporator rapidly increases at the start of operation, that is, the thermal stress generated in the evaporator rapidly increases. Is suppressed.

  In this case, the control unit, when the temperature of the evaporator is the specified value, the pressure of the portion of the heating medium flow path between the flow rate adjustment unit and the evaporator, the It is preferable to increase the number of revolutions of the pump so that a state higher than the pressure of a portion of the heating medium flow path downstream of the preheater is maintained.

  By doing so, it is possible to drive the pump while suppressing the occurrence of the so-called water hammer phenomenon in the evaporator (transition to a steady operation in which energy is recovered in the energy recovery unit). For example, when the pressure of the portion of the heating medium flow path between the flow rate adjustment unit and the evaporator is smaller than the pressure of the portion of the heating medium flow path downstream of the preheater, the evaporator or the preheater Since the liquid-phase heating medium condensed in the step becomes difficult to flow out of the preheater, the liquid-phase heating medium easily accumulates in the evaporator. In this state, when the heating medium in the gas phase flows into the evaporator, the heating medium is cooled by the heating medium (drain or mist) in the liquid phase in the evaporator and condensed, so that the volume rapidly decreases. Then, the pressure in the region where the heating medium has condensed becomes relatively low. As a result, the liquid-phase heating medium (droplets) moves toward the relatively low-pressure region, so that the liquid-phase heating medium collides with the inner surface of the evaporator (water hammer phenomenon). Can occur. On the other hand, in the present apparatus, the pressure of the part of the heating medium flow path between the flow rate adjustment unit and the evaporator is higher than the pressure of the part of the heating medium flow path downstream of the preheater. Is maintained, the occurrence of the water hammer phenomenon in the evaporator is suppressed.

  Also, in the present invention, the heating medium flow path further comprises a steam trap provided downstream of the evaporator and upstream of the preheater, wherein the steam trap is provided from the evaporator. It is preferable to prohibit the passage of the gas phase heating medium among the flowing out heating medium and allow the passage of the liquid phase heating medium.

  In this aspect, even if the heating medium flows out of the evaporator in a gaseous phase or a gas-liquid two-phase state, the passage of the gaseous heating medium is prohibited by the steam trap. Is suppressed. Therefore, the occurrence of the water hammer phenomenon in the preheater is suppressed.

  In this case, a gas discharge is provided in the heating medium channel between the steam trap and the preheater, and discharges a gaseous heating medium out of the heating medium flowing out of the evaporator to the outside. Preferably, a road is further provided.

  With this configuration, the inflow of the gaseous heating medium into the preheater is more reliably suppressed.

  Further, in the present invention, the flow rate adjusting unit may further include a first opening / closing valve provided at a portion of the heating medium flow path upstream of the evaporator, and the heating medium may bypass the first opening / closing valve. A bypass passage having an inner diameter smaller than the inner diameter of the passage; and a second on-off valve provided in the bypass passage, wherein the second on-off valve is configured to be adjustable in opening. Is preferred.

  In this aspect, the simple structure of providing the bypass flow path having an inner diameter smaller than the inner diameter of the heating medium flow path and the second on-off valve capable of adjusting the opening degree allows the heating medium in the gas phase to flow into the evaporator. The amount can be fine-tuned.

  In this case, the control unit is configured to control a pressure of a portion of the heating medium flow path upstream of the flow rate adjustment unit and a portion of the heating medium flow path between the flow rate adjustment unit and the evaporator. It is preferable to open the first on-off valve when the pressures are equal to each other.

  According to this configuration, the abrupt inflow of the vapor-phase heating medium into the evaporator when the first on-off valve is opened, that is, the rapid rise in the temperature of the evaporator is suppressed, and the evaporator of the vapor-phase heating medium is suppressed. The amount of inflow to the can be increased.

  Further, in the present invention, a pressure loss generating section is provided in a portion of the heating medium flow path downstream of the preheater, and the pressure loss generating section includes a heating medium in a liquid phase inside the preheater. It is preferable to apply a pressure loss to the heating medium flowing out of the preheater so as to satisfy

  With this configuration, since the inside of the preheater is filled with the liquid-phase heating medium, the occurrence of water hammer in the preheater is suppressed.

  Specifically, the pressure loss generating section is configured by a rising flow path having a shape that is formed by a part of the heating medium flow path and rises upward, and a position of a downstream end of the rising flow path is It is preferable that the height of the preheating device is set to be equal to or higher than the height of an inlet for allowing the heating medium to flow into the preheating device.

  With this configuration, a pressure loss can be easily generated in the heating medium flowing out of the preheater.

  Further, in the present invention, the heating medium flow path further includes an adjustment valve that is provided at a downstream side of the preheater and is capable of adjusting an opening degree. It is preferable to adjust the opening degree of the control valve so that the temperature or the pressure at a portion downstream of the control valve falls within a certain range.

  By doing so, the temperature or pressure of the heating medium flowing out of the preheater falls within a certain range, so that the heating medium can be used effectively.

  The present invention also provides an evaporator for evaporating the working medium by exchanging heat between a gaseous heating medium and a working medium supplied from the outside, and an energy for recovering energy from the working medium flowing out of the evaporator. A recovery section, a circulation path for connecting the evaporator and the energy recovery section and for flowing the working medium, a pump provided in the circulation path, and supplying the heating medium to the evaporator; A heating medium flow path; a flow rate adjustment unit provided at a portion of the heating medium flow path upstream of the evaporator; and a control unit, wherein the control unit regulates a temperature of the evaporator. A heat energy recovery device that controls the flow rate adjusting unit such that the flow rate of the gaseous phase heating medium into the evaporator gradually increases in a state where the pump is stopped until the flow rate reaches a value. .

  Also in this thermal energy recovery device, the flow rate of the gaseous heating medium (steam, etc.) into the evaporator gradually increases until the temperature of the evaporator reaches the specified value. Is suppressed. Furthermore, since the pump is stopped until the temperature of the evaporator reaches the specified value, a rapid inflow of the heating medium into the evaporator, that is, a rapid rise in the temperature of the evaporator is more reliably suppressed.

  In this case, the flow rate adjusting unit includes a first opening / closing valve provided at a portion of the heating medium flow path upstream of the evaporator, and bypasses the first opening / closing valve and the heating medium flow path And a second on-off valve provided in the bypass flow path, and the second on-off valve is preferably configured to be adjustable in opening. .

  Furthermore, in this case, the control unit is configured to control the pressure of a portion of the heating medium flow path upstream of the flow rate adjustment unit, between the flow rate adjustment unit and the evaporator in the heating medium flow path. It is preferable that the first on-off valve is opened when the pressures at the portions are equal to each other.

  The present invention also provides an evaporator for evaporating the working medium by exchanging heat with a gaseous heating medium and a working medium supplied from the outside, a heating medium flowing out of the evaporator, and flowing into the evaporator. A preheater that heats the working medium by exchanging heat with the working medium before performing the heat recovery, an energy recovery unit that recovers energy from the working medium flowing out of the evaporator, the preheater, the evaporator, and the energy recovery. A circulation flow path for connecting the parts and flowing the working medium, a pump provided in the circulation flow path, a heating medium flow path for supplying the heating medium to the evaporator and the preheater, A start-up method for starting the supply of the gaseous heating medium to the evaporator and the preheater, the method comprising: In the starting step, a start-up of the thermal energy recovery device, in which the flow rate of the gaseous heating medium into the evaporator is gradually increased while the pump is stopped until the temperature of the evaporator reaches a specified value. Provide a way.

  In this starting method, a sudden rise in the temperature of the evaporator at the time of starting (at the start of operation), that is, a sudden increase in thermal stress generated in the evaporator is suppressed.

In this case, a flow rate adjustment unit is provided at a position on the upstream side of the evaporator in the heating medium flow path, and further includes a pump driving start step of starting driving of the pump, wherein the pump driving start step includes: When the temperature of the evaporator reaches the specified value, the pressure of a portion of the heating medium channel between the flow rate adjustment unit and the evaporator is higher than the preheating of the heating medium channel. It is preferable to increase the rotation speed of the pump so as to maintain a state higher than the pressure at a portion downstream of the vessel.

  By doing so, it is possible to drive the pump while suppressing the occurrence of the so-called water hammer phenomenon in the evaporator (transition to a steady operation in which energy is recovered in the energy recovery unit).

  As described above, according to the present invention, it is possible to provide a thermal energy recovery device capable of suppressing a rapid increase in thermal stress generated in an evaporator at the start of operation, and a method of starting the same.

It is a figure showing an outline of composition of a thermal energy recovery device of a 1st embodiment of the present invention. 9 is a flowchart illustrating control contents of a control unit at the time of startup. It is a figure showing an outline of composition of a thermal energy recovery device of a 2nd embodiment of the present invention. It is a figure which shows the outline of a structure of the modification of the thermal energy recovery device of 1st Embodiment.

(1st Embodiment)
A heat energy recovery device according to a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the thermal energy recovery device includes an evaporator 10, a preheater 12, an energy recovery unit 13, a condenser 18, a pump 20, a circulation flow path 22, and a heating medium flow path 30. And a flow control unit 40 and a control unit 50.

  The evaporator 10 evaporates the working medium by exchanging heat between a gaseous heating medium (exhaust gas from a factory or the like) supplied from the outside and a working medium (HFC245fa or the like). The evaporator 10 has a first flow path 10a through which the working medium flows, and a second flow path 10b through which the heating medium flows. In the present embodiment, a brazing plate type heat exchanger is used as the evaporator 10. However, a so-called shell and tube heat exchanger may be used as the evaporator 10.

  The preheater 12 heats the working medium by causing heat exchange between the heating medium flowing out of the evaporator 10 and the working medium before flowing into the evaporator 10. The preheater 12 has a first flow path 12a through which the working medium flows, and a second flow path 12b through which the heating medium flows. In the present embodiment, a brazing plate type heat exchanger is also used as the preheater 12. However, what is called a shell-and-tube heat exchanger may be used as the preheater 12, similarly to the case of the evaporator 10. The preheater 12 has an inlet 12c for letting the heating medium flow into the second flow path 12b, and an outlet 12d for letting the heating medium flow out of the second flow path 12b. The preheater 12 is installed so that the position of the inlet 12c is higher than the position of the outlet 12d. The height position of the upstream end of the second flow path 12b of the preheater 12 is equal to or lower than the height position of the downstream end of the second flow path 10b of the evaporator 10. Is set.

  The energy recovery unit 13 includes an expander 14 and a power recovery machine 16. The circulation flow path 22 directly connects the preheater 12, the evaporator 10, the expander 14, the condenser 18, and the pump 20 in this order. A shutoff valve 25 is provided in a portion of the circulation flow path 22 between the evaporator 10 and the expander 14. Further, a bypass channel 24 that bypasses the expander 14 is provided in the circulation channel 22. An open / close valve 26 is provided in the bypass channel 24.

  The expander 14 is provided at a position downstream of the evaporator 10 in the circulation flow path 22. The expander 14 expands the gas-phase working medium flowing out of the evaporator 10. In the present embodiment, as the expander 14, a positive displacement screw expander having a rotor that is rotationally driven by expansion energy of a gas-phase working medium flowing out of the evaporator 10 is used. Specifically, the expander 14 has a pair of male and female screw rotors.

  The power recovery machine 16 is connected to the expander 14. In the present embodiment, a power generator is used as the power recovery device 16. The power recovery machine 16 has a rotating shaft connected to one of a pair of screw rotors of the expander 14. The power recovery machine 16 generates electric power by the rotation shaft rotating with the rotation of the screw rotor. In addition, a compressor or the like may be used as the power recovery machine 16 in addition to the power generator.

  The condenser 18 is provided at a position downstream of the expander 14 in the circulation channel 22. The condenser 18 condenses (liquefies) the working medium flowing out of the expander 14 by cooling it with a cooling medium (cooling water or the like) supplied from the outside.

  The pump 20 is provided at a portion of the circulation flow path 22 downstream of the condenser 18 (a portion between the condenser 18 and the preheater 12). The pump 20 pressurizes the liquid-phase working medium to a predetermined pressure and sends the working medium to the preheater 12. As the pump 20, a centrifugal pump having an impeller as a rotor, a gear pump in which the rotor includes a pair of gears, a screw pump, a trochoid pump, or the like is used.

  The heating medium flow path 30 is a flow path that supplies the heating medium from the external heat source that generates the gaseous heating medium to the evaporator 10 and the preheater 12 in this order. That is, the heating medium flow path 30 includes a supply flow path 30 a for supplying a vapor-phase heating medium to the evaporator 10 and a heating medium flowing out of the second flow path 10 b of the evaporator 10 to the second flow path of the preheater 12. It has a connection channel 30b for flowing into the 12b and a discharge channel 30c for discharging the heating medium from the preheater 12.

  The flow rate adjusting unit 40 is provided in the supply flow path 30a (a part of the heating medium flow path 30 upstream of the evaporator 10). The flow rate adjusting unit 40 is configured to be able to adjust the amount of the gas-phase working medium flowing into the evaporator 10. In the present embodiment, the flow rate adjusting unit 40 includes a first opening / closing valve V1 provided in the supply passage 30a, a bypass passage 32 bypassing the first opening / closing valve V1, and a second opening / closing valve 32 provided in the bypass passage 32. Opening / closing valve V2. The inside diameter (nominal diameter) of the bypass passage 32 is set smaller than the inside diameter (nominal diameter) of the supply passage 30a. It is preferable that the inner diameter of the bypass flow path 32 is set to be equal to or less than half of the inner diameter of the supply flow path 30a. The second on-off valve V2 is configured by an electromagnetic valve whose opening can be adjusted.

  In the present embodiment, a steam trap 38 and a gas vent channel 34 are provided in the connection channel 30b (a portion of the heating medium channel 30 between the evaporator 10 and the preheater 12). . The steam trap 38 prohibits passage of a gas phase heating medium among the heating medium flowing out of the evaporator 10 and allows passage of a liquid phase heating medium. The gas vent channel 34 is provided at a portion between the steam trap 38 and the preheater 12 in the connection channel 30b. The gas vent channel 34 is a channel for discharging the gas phase heating medium out of the heating medium flowing out of the evaporator 10 to the outside. A valve 35 is provided in the gas vent channel 34.

  The discharge channel 30c (a portion of the heating medium channel 30 downstream of the preheater 12) is a channel for discharging the heating medium after applying heat to the working medium in the preheater 12 to the outside. . In the present embodiment, the discharge channel 30c is open to the atmosphere. The pressure loss generating section 36 is provided in the discharge channel 30c. The pressure loss generator 36 applies a pressure loss to the heating medium flowing out of the preheater 12 so that the inside of the second flow path 12b of the preheater 12 is filled with the liquid phase heating medium. In the present embodiment, the pressure loss generating section 36 is configured by a rising flow path formed by a part of the discharge flow path 30c. The rising channel has a shape that rises upward. The position of the end 36a on the downstream side of the rising flow path is set to a height position equal to or higher than the height position of the inlet 12c of the preheater. An adjustment valve V3 whose opening degree can be adjusted is provided in a portion of the discharge passage 30c downstream of the pressure loss generating section 36.

  The control unit 50 mainly controls the first opening / closing valve V1, the second opening / closing valve V2, the pump 20, the shutoff valve 25, and the opening / closing valve 26 when the energy recovery device is started. Before starting (stopping) the apparatus, both the first on-off valve V1 and the second on-off valve V2 are closed, the pump 20 and the energy recovery unit 13 are both stopped, and the shutoff valve 25 is stopped. Is closed and the on-off valve 26 is open. Hereinafter, the control content of the control unit 50 will be described with reference to FIG.

  When the operation of the present apparatus is started, the control unit 50 opens the second on-off valve V2 and keeps increasing the opening degree of the second on-off valve V2 at a constant speed (step S11). Then, the heating medium in the gas phase gradually starts flowing into the evaporator 10 through the bypass passage 32. And the inflow increases gradually. As a result, the temperature T1 of the evaporator 10 gradually increases. Note that the temperature T1 of the evaporator 10 means a representative temperature of the evaporator 10. In the present embodiment (brazing plate type heat exchanger), the representative temperature is the surface temperature of the evaporator 10, and the temperature T <b> 1 is detected by the temperature sensor 51 provided on the surface of the evaporator 10. You. When a shell-and-tube heat exchanger is used as the evaporator 10, the representative temperature means the temperature of the flow path of the heat exchanger through which the heating medium flows.

  Next, the control unit 50 determines whether or not the temperature T1 of the evaporator 10 is higher than a specified value T0 (Step S12). As a result, when the temperature T1 of the evaporator 10 is lower than the specified value T0 (NO in step S11), the control unit 50 determines again whether the temperature T1 of the evaporator 10 is higher than the specified value T0. (Step S12). On the other hand, when temperature T1 of evaporator 10 is higher than specified value T0 (YES in step S11), control unit 50 increases the rotation speed of pump 20 (step S13).

  Then, the working medium is supplied to the preheater 12 and the evaporator 10. Here, since the shutoff valve 25 is closed and the on-off valve 26 is open, the working medium circulates in the circulation channel 22 via the bypass channel 24 (while bypassing the expander 14). At this time, in the evaporator 10, the gas-phase heating medium is cooled by the working medium (heats the working medium). The heating medium flowing out of the evaporator 10 in a liquid phase or a gas-liquid two-phase state flows into the preheater 12 via the steam trap 38. Then, the heating medium cooled by the working medium in the preheater 12 (giving heat to the working medium) is discharged to the outside through the discharge flow path 30c.

  Subsequently, the control unit 50 determines that the pressure Ps2 at a portion between the flow rate adjusting unit 40 and the evaporator 10 in the supply flow channel 30a is equal to the preheater 12 and the pressure loss generating unit (rising flow channel) in the discharge flow channel 30c. ) 36 (in the present embodiment, the sum of the atmospheric pressure and the pressure loss in the pressure loss generating unit 36) is determined (step S14). When the pressure Ps4 is higher than the pressure Ps2, a state in which the liquid-phase heating medium is hardly discharged from the discharge flow path 30c, that is, a state in which the liquid-phase heating medium easily stays in the second flow path 10b of the evaporator 10. It can be said that there is. The pressure Ps2 is detected by a pressure sensor 62 provided in a portion between the flow rate adjusting section 40 and the evaporator 10 in the supply flow path 30a, and the pressure Ps4 is detected in a preheater in the discharge flow path 30c. The pressure is detected by a pressure sensor 64 provided at a portion between the pressure sensor 12 and the pressure loss generating section 36.

  As a result of the determination, when the pressure Ps2 is higher than the pressure Ps4, the control unit 50 increases the rotation speed of the pump 20 (step S15), and when the pressure Ps2 is equal to or lower than the pressure Ps4, the control unit 50 Reduces the rotation speed of the pump 20 (step S16).

  Thereafter, the control unit 50 determines whether the opening degree of the second on-off valve V2 is the maximum (Step S17). As a result, when the opening of the second on-off valve V2 is not the maximum, the control unit 50 determines again whether the temperature T1 of the evaporator 10 is higher than the specified value T0 (step S12). On the other hand, when the opening degree of the second on-off valve V2 is the maximum, the control unit 50 determines whether or not the pressure Ps1 of the portion of the supply flow path 30a upstream of the flow rate adjustment unit 40 is equal to the pressure Ps2. A determination is made (step S18). The pressure Ps1 is detected by a pressure sensor 61 provided in a portion of the supply flow path 30a on the upstream side of the flow rate adjustment unit 40.

  As a result of the determination, when the pressure Ps1 is not equal to the pressure Ps2 (NO in step S18), the control unit 50 determines again whether the pressure Ps1 is equal to the pressure Ps2 (step S18). On the other hand, when the pressure Ps1 is equal to the pressure Ps2 (YES in step S18), the control unit 50 opens the first on-off valve V1 (step S19). Then, the entire amount of the gaseous heating medium flows into the evaporator 10 without being restricted by the first on-off valve V1 and the second on-off valve V2.

  Thereafter, the control unit 50 closes the on-off valve 26 and opens the shut-off valve 25, and drives the expander 14 and the power recovery device 16 (starts power recovery), thereby shifting to the warm-up operation. At this time, the control unit 50 determines the first saturation temperature of the portion between the flow rate adjustment unit 40 and the evaporator 10 in the supply flow path 30a and the first saturation temperature between the evaporator 10 and the expander 14 in the circulation flow path 22. The rotation speed of the pump 20 is increased so that the difference (pinch temperature) between the second saturation temperature of the portion and the second saturation temperature becomes the target value. Note that the first saturation temperature is calculated based on a detection value of a pressure sensor 62 provided in a portion between the flow rate adjustment unit 40 and the evaporator 10 in the supply flow path 30a, and the second saturation temperature is calculated as follows. , Is calculated based on a detection value of a pressure sensor 65 provided in a portion of the circulation flow path 22 between the evaporator 10 and the expander 14.

  Then, the control unit 50 adjusts the opening degree of the regulating valve V3 such that the temperature Ts6 or the pressure Ps6 of the portion of the discharge flow path 30c downstream of the pressure loss generating unit 36 falls within a certain range. Note that the temperature Ts6 and the pressure Ps6 are detected by a temperature sensor 66 and a pressure sensor 67, respectively, provided in a portion of the discharge passage 30c downstream of the pressure loss generating section 36.

  As described above, in the present thermal energy recovery apparatus, the flow rate of the gaseous heating medium (such as steam) into the evaporator 10 gradually increases until the temperature T1 of the evaporator 10 reaches the specified value T0. In addition, a rapid rise in the temperature T1 of the evaporator 10 is suppressed. Further, since the pump 20 is stopped until the temperature T1 of the evaporator 10 reaches the specified value T0, a rapid inflow of the heating medium into the evaporator 10, that is, a sudden increase in the temperature T1 of the evaporator 10, It is suppressed more reliably. Specifically, if the pump 20 is driven before the temperature T1 of the evaporator 10 reaches the specified value T0, the working medium flows into the evaporator 10, and the working medium cools the gas-phase heating medium. The condensation of the gaseous heating medium in the evaporator 10 is promoted. When the vapor-phase heating medium condenses, the volume (pressure) of the heating medium decreases, so that the inflow of the vapor-phase heating medium from the heating medium flow path 30 to the evaporator 10 is promoted. The temperature T1 may rise rapidly. On the other hand, in the present apparatus, the pump 20 is stopped until the temperature T1 of the evaporator 10 reaches the specified value T0. A rapid increase in thermal stress generated in the vessel 10 is suppressed.

  Further, when the temperature T1 of the evaporator 10 is the specified value T0, the control unit 50 determines that the pressure Ps2 in the portion of the heating medium flow path 30 between the flow rate adjustment unit 40 and the evaporator 10 is higher than the heating pressure. The rotation speed of the pump 20 is increased so that a state higher than the pressure Ps4 of the portion of the medium flow path 30 downstream of the preheater 12 is maintained.

  Therefore, it is possible to drive the pump 20 while suppressing the occurrence of the so-called water hammer phenomenon in the evaporator 10 (shift to the steady operation in which the energy recovery unit 13 recovers energy). For example, when the pressure Ps2 is smaller than the pressure Ps4, the liquid-phase heating medium condensed in the evaporator 10 or the preheater 12 is less likely to flow out of the preheater 12, so that the liquid-phase heating medium evaporates. It is easy to accumulate in the second flow path 10b of the vessel 10. When the gas phase heating medium flows into the second flow path 10b of the evaporator 10 in this state, the heating medium is cooled by the liquid phase heating medium (drain or mist) in the second flow path 10b and condensed. By doing so, the volume rapidly decreases. Then, the pressure in the region where the heating medium has condensed becomes relatively low. As a result, the liquid-phase heating medium (droplets) moves toward the region where the pressure is relatively low, so that the liquid-phase heating medium collides with the inner surface of the second flow path 10b of the evaporator 10. A phenomenon (water hammer phenomenon) may occur. On the other hand, in the present embodiment, since the state where the pressure Ps2 is higher than the pressure Ps4 is maintained, the occurrence of the water hammer phenomenon in the evaporator 10 is suppressed.

  In the present embodiment, a steam trap 38 is provided in the connection channel 30b. Therefore, even if the heating medium flows out of the evaporator 10 in a gaseous phase or a gas-liquid two-phase state, the passage of the gaseous heating medium is prohibited by the steam trap 38, so that the gaseous phase The inflow of the heating medium is suppressed. Therefore, the occurrence of the water hammer phenomenon in the preheater 12 is suppressed.

  Furthermore, since the gas vent channel 34 is provided in the connection channel 30b between the steam trap 38 and the preheater 12, the inflow of the gaseous heating medium into the preheater 12 is more reliable. Is suppressed.

  In the present embodiment, the flow control unit 40 includes the first on-off valve V1, the bypass flow path 32 having an inner diameter smaller than the inner diameter of the supply flow path 30a, and the second on-off valve V2. . In this embodiment, the evaporator 10 of the gaseous heating medium has a simple structure in which the bypass flow path 32 having an inner diameter smaller than the inner diameter of the supply flow path 30a and the second on-off valve V2 whose opening can be adjusted are provided. It is possible to finely adjust the inflow amount into the tank.

  Further, in the present embodiment, the control unit 50 controls the pressure Ps1 at a position upstream of the flow rate adjusting unit 40 in the supply flow path 30a and the pressure Ps1 between the flow rate adjusting unit 40 and the evaporator 10 in the supply flow path 30a. The first on-off valve V1 is opened when the pressures Ps2 at the position of the above are equal to each other. For this reason, the rapid inflow of the gas phase heating medium into the evaporator 10 when the first on-off valve V1 is opened, that is, the rapid rise of the temperature T1 of the evaporator 10, is suppressed, and the evaporation of the gas phase heating medium is suppressed. The flow rate into the vessel 10 can be increased.

  Further, in the present embodiment, the pressure loss generating section 36 including the rising flow path is provided in the discharge flow path 30c. For this reason, since the inside of the second flow path 12b of the preheater 12 is filled with the liquid phase heating medium, the occurrence of water hammer in the preheater 12 is suppressed. If the pressure loss generating section 36 is not provided, the flow of the liquid phase heating medium out of the second flow path 12b of the preheater 12 is promoted by the influence of gravity. Then, the pressure of the portion of the connection flow path 30b downstream of the steam trap 38 (including the preheater 12 and the discharge flow path 30c) becomes relatively small, so that the heating medium flowing out of the evaporator 10 is discharged from the steam trap 38. After passing through, which may result in a gaseous heating medium. In this case, a water hammer phenomenon may occur in the preheater 12.

  In addition, in the present embodiment, the control unit 50 controls the opening degree of the control valve V3 so that the temperature T6 or the pressure Ps6 of the portion of the discharge flow path 30c downstream of the control valve V3 falls within a certain range. To adjust. Therefore, the heating medium discharged from the discharge passage 30c can be effectively used.

(2nd Embodiment)
Next, a heat energy recovery device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 mainly shows a portion different from the first embodiment. In the second embodiment, only the portions different from the first embodiment will be described, and the description of the same structure, operation, and effects as those in the first embodiment will be omitted.

  In the present embodiment, an electromagnetic on-off valve capable of adjusting the opening degree is used as the pressure loss generating unit 36. In other words, in the present embodiment, the rising channel of the first embodiment is omitted, and the adjustment valve V3 also functions as the pressure loss generating unit 36.

  The control unit 50 determines that the pressure Ps4 at a portion between the preheater 12 and the pressure loss generating unit 36 in the discharge flow passage 30c is a pressure at a portion between the steam trap 38 and the preheater 12 in the connection flow passage 30b. The opening of the pressure loss generating section 36 (adjustment valve V3) is adjusted so as to be Ps3 or more. The pressure Ps3 is detected by a pressure sensor 63 provided in a portion between the steam trap 38 and the preheater 12 in the connection flow path 30b.

  Also in the present embodiment, a pressure loss can be easily generated in the heating medium flowing out of the preheater 12.

(Modification)
As shown in FIG. 4, in the thermal energy recovery device, it is not always necessary to provide a preheater. When the preheater is omitted, a portion of the heating medium flow path 30 downstream of the steam trap 38 and a configuration provided in the portion can be omitted. Other structures are the same as those in FIG. Even in this case, the flow rate of the gaseous heating medium (such as steam) into the evaporator 10 gradually increases until the temperature T1 of the evaporator 10 reaches the specified value T0. Sharp rise is suppressed. Further, since the pump 20 is stopped until the temperature T1 of the evaporator 10 reaches the specified value T0, a rapid inflow of the heating medium into the evaporator 10, that is, a sudden increase in the temperature T1 of the evaporator 10, It is suppressed more reliably.

  It should be understood that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

  For example, the flow rate adjusting unit 40 may be configured by a single solenoid valve. That is, the bypass flow path 32 and the second on-off valve V2 in the flow rate adjusting unit 40 may be omitted, and an electromagnetic valve whose opening degree can be adjusted may be used as the first on-off valve V1.

DESCRIPTION OF SYMBOLS 10 Evaporator 12 Preheater 13 Energy recovery part 20 Pump 22 Circulation flow path 30 Heating medium flow path 32 Bypass flow path 34 Gas release flow path 36 Pressure loss generation part 38 Steam trap 40 Flow rate adjustment part 50 Control part V1 1st on-off valve V2 Second on-off valve V3 Adjustment valve

Claims (14)

An evaporator that evaporates the working medium by exchanging heat between the gaseous heating medium and the working medium supplied from the outside,
A preheater that heats the working medium by exchanging heat between the heating medium flowing out of the evaporator and the working medium before flowing into the evaporator,
An energy recovery unit that recovers energy from the working medium flowing out of the evaporator,
A circulation flow path for connecting the preheater, the evaporator, and the energy recovery unit and flowing the working medium,
A pump provided in the circulation channel,
A heating medium flow path for supplying the heating medium to the evaporator and the preheater,
A flow rate adjustment unit provided at a position upstream of the evaporator in the heating medium flow path,
And a control unit,
The controller is configured to stop the pump until the temperature of the evaporator reaches a specified value. To control the heat energy recovery device. The thermal energy recovery device according to claim 1,
The controller is configured such that, when the temperature of the evaporator is the specified value, the pressure of a portion of the heating medium flow path between the flow rate adjusting unit and the evaporator is higher than the pressure of the heating medium flow path. A heat energy recovery device that increases the rotation speed of the pump so that a state that is higher than the pressure at a portion downstream of the preheater is maintained. The thermal energy recovery device according to claim 2,
The heating medium flow path further comprises a steam trap provided at a position downstream of the evaporator and upstream of the preheater,
The thermal energy recovery device, wherein the steam trap prohibits passage of a gas phase heating medium among the heating medium flowing out of the evaporator and allows passage of a liquid phase heating medium. The thermal energy recovery device according to claim 3,
A gas vent channel is provided in the heating medium channel between the steam trap and the preheater and configured to discharge a gas phase heating medium out of the heating medium flowing out of the evaporator to the outside. , Thermal energy recovery equipment. The thermal energy recovery device according to any one of claims 1 to 4,
The flow rate adjusting unit,
A first on-off valve provided at a portion of the heating medium flow path upstream of the evaporator;
A bypass passage that bypasses the first on-off valve and has an inner diameter smaller than the inner diameter of the heating medium passage;
A second on-off valve provided in the bypass flow path,
The thermal energy recovery device, wherein the second on-off valve is configured to be capable of adjusting an opening degree. The thermal energy recovery device according to claim 5,
The control unit is a pressure of a portion of the heating medium flow path upstream of the flow rate adjustment unit, a pressure of a portion of the heating medium flow path between the flow rate adjustment unit and the evaporator, A heat energy recovery device that opens the first on-off valve when the values are equal to each other. The thermal energy recovery device according to any one of claims 1 to 6,
A pressure loss generating section is provided in a portion of the heating medium flow path downstream of the preheater,
The thermal energy recovery device, wherein the pressure loss generating section applies a pressure loss to the heating medium flowing out of the preheater so that the inside of the preheater is filled with a heating medium in a liquid phase. The thermal energy recovery device according to claim 7,
The pressure loss generating section is configured by a rising channel having a shape configured by a part of the heating medium channel and rising upward.
The position of the downstream end of the rising flow path is set to a height position equal to or higher than the height position of an inlet of the preheater for flowing the heating medium into the preheater. Have a thermal energy recovery device. The thermal energy recovery device according to any one of claims 1 to 8,
The heating medium flow path further includes an adjustment valve that is provided at a downstream side of the preheater and that can adjust an opening degree,
The thermal energy recovery device, wherein the control unit adjusts an opening degree of the adjustment valve such that a temperature or a pressure of a portion of the heating medium flow path downstream of the adjustment valve falls within a certain range. An evaporator that evaporates the working medium by exchanging heat between the gaseous heating medium and the working medium supplied from the outside,
An energy recovery unit that recovers energy from the working medium flowing out of the evaporator,
A circulation flow path for connecting the evaporator and the energy recovery unit and flowing the working medium,
A pump provided in the circulation channel,
A heating medium flow path for supplying the heating medium to the evaporator,
A flow rate adjustment unit provided at a position upstream of the evaporator in the heating medium flow path,
And a control unit,
The control unit is configured to stop the pump until the temperature of the evaporator reaches a specified value.In the state where the pump is stopped, the flow rate adjusting unit is configured to gradually increase the flow rate of the gaseous heating medium into the evaporator. To control the heat energy recovery device. The thermal energy recovery device according to claim 10,
The flow rate adjusting unit,
A first on-off valve provided in a portion of the heating medium flow path upstream of the evaporator,
A bypass flow path that bypasses the first on-off valve and has an inner diameter smaller than the inner diameter of the heating medium flow path;
A second on-off valve provided in the bypass flow path,
The thermal energy recovery device, wherein the second on-off valve is configured to be capable of adjusting an opening degree. The thermal energy recovery device according to claim 11,
The control unit is a pressure of a portion of the heating medium flow path upstream of the flow rate adjustment unit,
The thermal energy recovery device, wherein the first on-off valve is opened when a pressure in a portion of the heating medium flow path between the flow rate adjustment unit and the evaporator is equal to each other. An evaporator that evaporates the working medium by exchanging heat between the gaseous heating medium and the working medium supplied from the outside,
A preheater that heats the working medium by exchanging heat between the heating medium flowing out of the evaporator and the working medium before flowing into the evaporator,
An energy recovery unit that recovers energy from the working medium flowing out of the evaporator,
A circulation flow path for connecting the preheater, the evaporator, and the energy recovery unit and flowing the working medium,
A pump provided in the circulation channel,
A heating medium flow path for supplying the heating medium to the evaporator and the preheater,
A method for activating a thermal energy recovery device comprising:
A heating medium supply start step of starting supply of the gas phase heating medium to the evaporator and the preheater,
In the heating medium supply start step, until the temperature of the evaporator reaches a specified value, in a state where the pump is stopped, gradually increase the amount of the gaseous phase heating medium flowing into the evaporator, How to start the collection device. The method for activating a thermal energy recovery device according to claim 13,
A flow rate adjustment unit is provided in a portion of the heating medium flow path upstream of the evaporator,
The method further includes a pump driving start step of starting driving of the pump,
In the pump driving start step, when the temperature of the evaporator reaches the specified value, the pressure of a portion of the heating medium flow path between the flow rate adjustment unit and the evaporator is increased by the heating. A method for activating a thermal energy recovery device, comprising: increasing the rotation speed of the pump so that a state higher than the pressure of a portion of the medium flow path downstream of the preheater is maintained.

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