JP5460663B2 - Power generator - Google Patents

Description

  The present invention relates to a power generator.

  As a power generator, flash power generation in which a generator is driven by a water vapor flash has been widely introduced. However, in recent years, from the viewpoint of energy saving, there is an increasing need for a system that can generate power using low-temperature heat that cannot be used for flash power generation in order to recover exhaust heat.

  As such a power generation device, a working fluid evaporator, a turbine for causing the working fluid vapor to perform expansion work, and a working fluid vapor for driving a turbine or an expander (expander) by a low-boiling working medium. There is a binary power generation system using a Rankine cycle, which is a thermal cycle in which a working fluid is circulated in a closed loop in which a condenser for condensing the gas and a circulation pump for circulating the working fluid are connected in series.

  For example, the binary power generation system disclosed in Patent Document 1 uses a screw turbine (also referred to as a screw expander or a screw expander) that is a positive displacement fluid machine as a turbine, and rotates the screw turbine by a Rankine cycle to generate a generator. This is a binary power generator that drives the motor.

  In the binary power generation system of Patent Document 1, a screw turbine that is a positive displacement fluid machine is used as a turbine. In the case of this screw turbine, a configuration for supplying a working medium in which lubricating oil is mixed to the screw turbine is often employed for lubrication, sealing, etc. of a pair of male and female screw rotors constituting the screw turbine. .

  Many binary power generation systems include an emergency shut-off valve for stopping the circulation of the working medium in the circulation flow path (“working medium loop” referred to in Patent Document 1) in order to cope with an emergency. It has been. For example, in the binary power generation system of Patent Document 1, an emergency shutoff valve (V1) is installed in the middle of the working medium loop from the evaporator (12) to the screw turbine (14) as shown in FIG. Yes. The emergency shut-off valve (V1) is a kind of stop valve, and serves to close the working medium loop when the pressure exceeds a set value for some reason.

  Moreover, in the binary power generation system of Patent Document 1, the upstream part of the emergency shutoff valve (V1) of the working medium loop and the downstream part of the oil separator (16) are connected by a bypass pipe (28), A pressure control valve (V2) is installed in the bypass line (28). The pressure control valve (V2) detects the pressure on the upstream side of the screw turbine (14), that is, on the inlet side, and when the pressure exceeds a set value, the pressure control valve (V2) passes through the bypass pipe (28) to the upstream side of the screw turbine (14). The side (entrance side) and the downstream side (exit side) are communicated with each other.

JP 09-088511 A

  In the system, even after the working medium loop is closed by the emergency shut-off valve (V1), if hot water continues to be supplied to the evaporator (12), the emergency shut-off valve (V1) more specifically on the upstream side of the screw turbine (14). The temperature of the working medium in the working medium loop on the upstream side of) rises, and the pressure also rises. In addition, if cold water continues to be supplied to the condenser (18) even after the working medium loop is closed by the emergency shutoff valve (V1), the temperature of the working medium in the working medium loop on the downstream side of the screw turbine (14). Decreases and the pressure also decreases.

  Then, when the emergency shut-off valve (V1) is opened from that state and the circulation of the working medium in the working medium loop is restarted (the binary power generation system is restarted), the screw turbine (14) is connected between the upstream side and the downstream side. Due to the excessive pressure difference, the screw rotor may suddenly accelerate, causing a problem such as damage to the bearing. If the working medium loop is closed, the supply of hot water to the evaporator (12) is stopped, and the supply of cold water to the condenser (18) is also stopped, the upstream side and the downstream side of the screw turbine (14) Can be suppressed, but it is difficult to eliminate the pressure difference at all.

  In Patent Document 1, in order to open the pressure control valve (V2) when the pressure on the upstream side, that is, the inlet side of the screw turbine (14) is sensed and the pressure exceeds a set value, the pressure control valve (V2) is opened. The upstream side (inlet side) and the downstream side (outlet side) of the screw turbine (14) can be communicated with each other. For this reason, by opening the pressure control valve (V2), it is possible to suppress the possibility of problems such as the rapid acceleration of the screw rotor and the breakage of the bearing as described above.

  However, the working medium loop is closed by the emergency shutoff valve (V1), the pressure control valve (V2) is opened, and the upstream side (inlet side) and the downstream side of the screw turbine (14) through the bypass line (28). Even if the (exit side) is connected, a high-pressure working medium remains between the emergency shutoff valve (V1) and the upstream side (inlet side) of the screw turbine (14). Therefore, since the force which rotates a screw turbine (14) generate | occur | produces, even if a working-medium loop is closed by the emergency shut-off valve (V1), the problem that operation | movement of a binary power generation system cannot be stopped immediately remains. ing.

  Further, when the working medium loop is closed by the emergency shut-off valve (V1), the working medium loop between the emergency shut-off valve (V1) and the upstream side (inlet side) of the screw turbine (14) has an emergency shut-off valve (V1). ) Holds the working medium having a pressure substantially equal to the pressure at the time when the working medium loop is closed. On the other hand, the working medium having a pressure higher than the pressure is held on the upstream side of the emergency shut-off valve (V1) by the steam generated by supplying warm water to the evaporator (12). Therefore, when the upstream side (inlet side) and the downstream side (outlet side) of the screw turbine (14) are communicated with each other through the bypass line (28), the working medium loop is closed by the emergency shut-off valve (V1). The working medium is slightly higher than the pressure of the emergency shutoff valve (V1), more specifically from the working medium loop between the emergency shutoff valve (V1) and the evaporator (12). ) On the downstream side (exit side). For this reason, in the working medium loop between the emergency shutoff valve (V1) and the upstream side (inlet side) of the screw turbine (14) and the working medium loop on the downstream side (outlet side) of the screw turbine (14), A state in which the level of pressure is reversed may occur.

  In this state where the pressure level is reversed, a so-called reverse thrust force is applied to the screw turbine (14) from the downstream side (exit side) to the upstream side (inlet side) of the screw turbine (14). Due to this reverse thrust force, the end surface on the upstream side (entrance side) of the screw rotor constituting the screw turbine (14) comes into contact with the surface of the casing facing the end surface, or the bearing is damaged. There is a risk of malfunction.

  Therefore, the present invention has been made in view of the above problems, and the flow of the working medium is temporarily stopped by closing an on-off valve such as an emergency shutoff valve interposed in the circulation flow path (working medium loop). After that, even if the on-off valve is opened and the circulation of the working medium in the circulation channel (working medium loop) is resumed (the power generation device is restarted), the expander is prevented from suddenly accelerating, After stopping the circulation of the working medium, it is possible to stop the operation of the power generator substantially early, and further, the reverse thrust force is not loaded on the expander, and the occurrence of troubles due to the reverse thrust force loaded on the expander is prevented. It aims at providing the electric power generating apparatus which can be avoided.

  In order to achieve the above object, the present invention introduces a circulation flow path through which a working medium flows, an evaporator that evaporates the working medium by a heating medium supplied from the outside, and an evaporated working medium. An expander that rotationally drives the generator, a condenser that introduces the working medium discharged from the expander and condenses the working medium by a cooling medium supplied from the outside, and a working medium condensed by the condenser A working medium pump re-supplied to the evaporator, an open / close valve disposed in a portion of the circulation channel between the evaporator and the inlet side of the expander; A pressure equalizing flow path, in the circulation flow path, capable of communicating a portion between the on-off valve and the evaporator, and a portion between the outlet side of the expander and the condenser; An expander bypass valve is provided In the circulation channel, an expander bypass channel capable of communicating a portion between the on-off valve and the inlet side of the expander, and a portion between the outlet side of the expander and the condenser; When the operation is stopped, control is performed to close the open / close valve and open the expander bypass valve and the pressure equalizing valve after the working medium pump is stopped. And a controller that performs control to close the expander bypass valve and the pressure equalizing valve before driving the pump.

  In this configuration, when the operation is stopped, the controller closes the open / close valve interposed in the circulation flow path between the evaporator and the inlet side of the expander, while the pressure equalizing valve and the expansion valve are stopped after the working medium pump is stopped. Open the machine bypass valve. For this reason, the pressure in the circulation channel from the evaporator to the inlet side of the expander (that is, the pressure in the circulation channel before and after the on-off valve) is almost equal to the pressure in the circulation channel on the outlet side of the expander. Will be equal. As a result, it is possible to prevent the expander from continuing to be driven due to the pressure difference, and it is possible to substantially stop the operation of the power generation device at an early stage after the working medium is stopped. Further, it is possible to avoid a situation in which the upstream side (inlet side) pressure and the downstream side (outlet side) pressure of the expander are reversed. Therefore, it is possible to avoid the occurrence of problems associated with the reverse thrust force applied to the expander. Further, at the time of start-up, the open / close valve is opened while the open pressure equalizing valve and the expander bypass valve are closed, so that the working medium pump is driven to recirculate the working medium (restart the binary power generator). It is also possible to prevent the expander from suddenly accelerating when starting up.

  Here, when the operation is stopped, control may be performed to open the expander bypass valve and the pressure equalizing valve when a predetermined time has elapsed after the working medium pump is stopped.

  On the other hand, when an evaporating pressure sensor is provided between the evaporator and the on-off valve in the circulation flow path, the evaporating pressure sensor is used after the working medium pump is stopped when the operation is stopped. Control may be performed to open the expander bypass valve and the pressure equalizing valve when the detected pressure is equal to or higher than a predetermined upper limit value.

  According to this configuration, since the pressure equalizing valve is not unnecessarily opened, the effect of avoiding the occurrence of problems associated with the reverse thrust force applied to the expander can be further ensured.

  The circulation channel is provided with an evaporation pressure sensor disposed between the evaporator and the on-off valve, and a discharge pressure sensor disposed between the expander and the condenser. In this case, when the operation is stopped, a differential pressure between the pressure detected by the evaporation pressure sensor and the pressure detected by the discharge pressure sensor after the working medium pump is stopped is equal to or greater than a predetermined value. When it becomes, control which opens the said expander bypass valve and the said pressure equalizing valve may be performed.

  In this configuration, since the pressure equalizing valve is not unnecessarily opened, the effect of avoiding the occurrence of problems associated with the reverse thrust force applied to the expander can be further ensured.

  As described above, according to the present invention, an on-off valve such as an emergency shut-off valve provided in a circulation flow path (working medium loop) is closed to temporarily stop the flow of the working medium. , And the circulation of the working medium in the circulation channel (working medium loop) is restarted (the power generation device is restarted), and the expander does not accelerate rapidly, and the working medium is stopped. Thereafter, the operation of the power generator can be stopped substantially at an early stage. Further, the reverse thrust force is not applied to the expander, and the occurrence of a problem associated with the reverse thrust force applied to the expander can be avoided.

It is a figure which shows the structure of the electric power generating apparatus which concerns on 1st Embodiment of this invention. It is a flowchart for demonstrating the control action at the time of starting of the said electric power generating apparatus. It is a flowchart for demonstrating the control action at the time of the operation stop of the said electric power generating apparatus. It is a figure which shows the structure of the electric power generating apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart for demonstrating the control action at the time of starting of the electric power generating apparatus shown in FIG. It is a flowchart for demonstrating the control action at the time of the operation stop of the electric power generating apparatus shown in FIG. It is a figure which shows the structure of the electric power generating apparatus which concerns on 3rd Embodiment of this invention. It is a flowchart for demonstrating the control action at the time of starting of the electric power generating apparatus shown in FIG. It is a flowchart for demonstrating the control action at the time of the operation stop of the electric power generating apparatus shown in FIG. It is a flowchart for demonstrating the control action at the time of starting of the electric power generating apparatus which concerns on the modification of 3rd Embodiment of this invention. It is a flowchart for demonstrating the control action at the time of the operation stop of the electric power generating apparatus which concerns on the modification of 3rd Embodiment of this invention. It is a figure which shows the structure of the electric power generating apparatus which concerns on 4th Embodiment of this invention. It is a flowchart for demonstrating the control action at the time of starting of the electric power generating apparatus shown in FIG. It is a flowchart for demonstrating the control action at the time of the operation stop of the electric power generating apparatus shown in FIG. It is a figure which shows the structure of the conventional electric power generating apparatus.

  Embodiments of the present invention will now be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a configuration of a power generator 1 according to a first embodiment of the present invention. The power generation device 1 is a Rankine cycle heat engine including a circulation passage 6 provided with an evaporator 2, a screw expander 3, a condenser 4, and a working medium pump 5. A working medium (for example, a chlorofluorocarbon heat medium such as R245fa) is enclosed in the circulation channel 6.

  The evaporator 2 is a heat exchanger that evaporates the working medium by exchanging heat between a working medium (for example, steam collected from a well or steam produced by a boiler) supplied from a heat source outside the apparatus and the working medium. is there. The working medium evaporated in the evaporator 2 is introduced into the screw expander 3 through the circulation channel 6. In the screw expander 3, when the working medium expands, a screw rotor (not shown) is rotationally driven. The working medium that is expanded by the screw expander 3 and discharged in a state where the pressure is reduced is introduced into the condenser 4. The condenser 4 is a heat exchanger that cools and condenses the working medium by exchanging heat between the cooling medium supplied from a cooling source outside the apparatus (for example, cooling water supplied from a river or a cooling tower) and the working medium. It is. The working medium condensed into a liquid by the condenser 4 is supplied again to the evaporator 2 by the working medium pump 5.

  A generator 7 is connected to the rotating shaft of the screw expander 3. The generator 7 converts the rotational energy of the screw expander 3 into electric energy, that is, generates power.

  In the power generation apparatus 1, as described above, the screw expander 3, which is a positive displacement fluid machine, is used as a drive unit for driving the generator 7. In the present embodiment, a screw expander is used as the expander, but the present invention is not limited to this configuration, and another form of expander may be used.

  In order to lubricate and seal a pair of male and female screw rotors (not shown) constituting the screw expander 3, the screw expander 3 is supplied with a working medium mixed with lubricating oil. However, if the lubricating oil is supplied to the condenser 4 and the evaporator 2 which are heat exchangers, it may lead to problems such as a decrease in heat exchange efficiency. For this reason, in this power generator 1, an oil separator 8 is provided on the outlet side of the screw expander 3. The working medium mixed with the lubricating oil is separated from the lubricating oil by the oil separator 8. The lubricating oil separated from the working medium by the oil separator 8 is supplied to the vicinity of the entry side of the screw expander 3 through an oil supply passage 10 provided with an oil pump 9.

  The heating medium is supplied to the evaporator 2 through the heating medium supply channel 11, and heat exchange with the working medium is performed in the evaporator 2. After passing through the evaporator 2, the heating medium is further circulated to the heat source through the discharge passage 12 outside the heating medium, or is secondarily used or discarded outside.

  The cooling medium is supplied to the cooling medium supply flow path 13, passes through the condenser 2, and further circulates or is discarded to the cooling source through the cooling medium discharge flow path 14.

  An opening / closing valve 15 is provided in a flow path between the evaporator 2 and the inlet side of the screw expander 3 in the circulation flow path 6. Further, a pressure equalizing channel 17 is connected to the circulation channel 6. The pressure equalizing flow path 17 has one end connected to the flow path 6 a between the on-off valve 15 and the evaporator 2, while the other end is a flow path 6 b on the outlet side of the screw expander 3 (with the screw expander 3 and It is connected to a flow path 6b) between the oil separator 8. The pressure equalizing flow path 17 is provided with a pressure equalizing valve 16 composed of an on-off valve. That is, the pressure equalizing flow path 17 opens the pressure equalizing valve 16, thereby condensing the portion between the on-off valve 15 and the evaporator 2 in the circulation flow path 6 and the outlet side of the screw expander 3 in the circulation flow path 6. The site | part between the container 4 (or oil separator 8) can be connected. The other end of the pressure equalizing flow path 17 may be connected to a flow path between the oil separator 8 and the condenser 4, or may be connected to a flow path inside the condenser.

  An expansion machine bypass channel 19 is connected to the circulation channel 6. One end of the expander bypass channel 19 is connected to the channel 6 c between the opening / closing valve 15 and the inlet side of the screw expander 3, and the other end is located downstream of the pressure equalizing valve 16 in the pressure equalizing channel 17. It is connected. Accordingly, the expander bypass flow channel 19 communicates with the flow channel 6 b on the outlet side of the screw expander 3 through the pressure equalization flow channel 17. The expander bypass passage 19 is provided with an expander bypass valve 18 composed of an on-off valve. Therefore, the expander bypass channel 19 opens the expander bypass valve 18, thereby opening the site between the on-off valve 15 in the circulation channel 6 and the inlet side of the screw expander 3 and the screw in the circulation channel 6. The site | part between the exit side of the expander 3 and the condenser 4 (or oil separator 8) can be connected. As will be described later, the power generator 1 is configured to open and close the pressure equalizing valve 16 and the expander bypass valve 18 in accordance with the opening and closing of the opening and closing valve 15. The other end of the expander bypass flow channel 19 may be connected to the flow channel 6 b on the outlet side of the screw expander 3 instead of the pressure equalization flow channel 17.

  The power generation apparatus 1 according to the present embodiment is provided with a controller 20 that is a control unit. The controller 20 is roughly divided into three parts. First, the controller 20 includes an input unit 20a configured with a keyboard, an input switch, and the like. Furthermore, the controller 20 receives an input signal output from the input unit 20a and the like, performs an operation according to the input signal, and appropriately configures components other than the controller 20 constituting the power generation apparatus 1, and a display unit described later. An arithmetic unit 20b that outputs a control signal to 20c is provided. And the controller 20 is provided with the display part 20c as an output part which performs a predetermined | prescribed display (or audio | voice output depending on the case) according to the output from the calculating part 20b.

  The calculation unit 20b of the controller 20 includes a ROM, a RAM, a CPU, and the like, and exhibits a predetermined function by executing a program stored in the ROM. This function includes opening / closing control means for opening / closing the opening / closing valve 15, the pressure equalizing valve 16, and the expander bypass valve 18. More specifically, the calculation unit 20b of the controller 20 receives an input signal output from the input unit 20a or the like based on an operation of the operator of the power generation device 1 or an input signal from components (various sensors) other than the controller 20. Accordingly, an output signal for opening and closing the on-off valve 15, the pressure equalizing valve 16, and the expander bypass valve 18 is output.

  Next, operation control of the power generation device 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a flowchart showing operation control of the power generation device 1 at the time of activation. FIG. 3 is a flowchart showing the operation control of the power generator 1 when the operation is stopped.

  First, the control operation of the power generation device 1 at the time of activation will be described. First, when the operator of the power generation device 1 performs an operation for activation (such as pressing a “start switch” (not shown)), an activation command is transmitted from the input unit 20a of the controller 20 to the arithmetic unit 20b. (Step St1).

  Upon receiving the start command, the calculation unit 20b of the controller 20 opens the expander bypass valve 18 and opens the pressure equalizing valve 16 (step St2). Subsequently, a predetermined time is counted by a timer (step St3), and when the predetermined time has elapsed, the on-off valve 15 is opened (step St4). Then, the expander bypass valve 18 is closed, and the pressure equalizing valve 16 is closed (step St5). Finally, the working medium pump 5 is started (step St6).

  That is, at the time of activation, the power generator 1 is configured to close the expander bypass valve 18 and close the pressure equalizing valve 16 (step St5) at the same time as or after opening the on-off valve 15 (step St4). Yes. The opening / closing operation of the opening / closing valve 15 and the like is performed before the working medium pump 5 is started.

  At the time of starting, first, the pressure equalizing valve 16 and the expander bypass valve 18 are opened, so that the pressure upstream of the on-off valve 15 (the flow path 6a between the on-off valve 15 and the evaporator 2) and the on-off valve 15 are increased. The pressure on the downstream side (flow path 6c between the opening and closing valve 15 and the inlet side of the screw expander 3) is equalized, and the pressure on the inlet side of the screw expander 3 (the pressure on the downstream side of the opening and closing valve 15). ) And the pressure in the flow path 6b on the outlet side of the expander 3 are equalized. As a result, even when the pressure equalizing valve 16 of the pressure equalizing flow path 17 is opened while the on-off valve 15 is closed when the working medium pump is started, the inlet side of the screw expander 3 (the on-off valve 15 and the screw expander It is possible to avoid a situation in which the pressure on the outlet side becomes higher than the upstream side (inlet side) of 3. Moreover, sudden acceleration of the screw expander 3 can be suppressed.

  Next, the control operation of the power generation device 1 when the operation is stopped will be described with reference to FIG. When the operation is stopped, first, when an operation for stopping the operation (such as pushing a “stop switch” not shown) is performed by the operator of the power generation device 1, a stop command is sent from the input unit 20a of the controller 20 to the calculation unit 20b. It is transmitted to (step St11).

  When the calculation unit 20b of the controller 20 receives the input of the stop command, the calculation unit 20b stops the working medium pump 5 (step St12). Subsequently, the open / close valve 15 is closed and the expander bypass valve 18 is opened (step St13). Then, a predetermined time (which may be zero time in some cases) determined by a timer is counted (step St14), and when the predetermined time has elapsed, the pressure equalizing valve 16 is finally opened (step St15).

  As described above, the power generation device 1 opens the expander bypass valve 18 at the same time as or after the closing of the on-off valve 15 when the operation is stopped (step St13), and then opens the pressure equalizing valve 16. (Step St15).

  That is, when the working medium pump 5 is stopped, if the high pressure working medium remains in the flow path 6c between the opening / closing valve 15 and the inlet side of the screw expander 3, The force that rotates the expander 3 will work. However, in this power generator 1, the on-off valve 15 is closed (simultaneously), and the expander bypass valve 18 is opened, thereby reducing the pressure in the flow path 6 c to the inlet side of the expander 3. The pressure of the flow path 6b after the outlet side of the expander 3 is set to the same pressure. As a result, it is possible to reduce the occurrence of a force for rotating the screw expander 3 after the on-off valve 15 is closed. That is, the operation of the power generator 1 can be substantially stopped early after the stop of the distribution of the working medium.

  Further, at the time of start-up, before the opening / closing valve 15 is opened (step St4), the expander bypass valve 18 is opened and the pressure equalizing valve 16 is opened (step St2). Further, when the operation is stopped, At the same time as or after the closing of the on-off valve 15, the expander bypass valve 18 is opened (step St13) and the pressure equalizing valve 16 is opened (step St15), whereby the working medium pump 5 is started to actuate the working medium. Even if the distribution of the power is resumed (the binary power generator 1 is restarted), the screw expander 3 is not accelerated rapidly, and the reverse thrust force is not applied to the expander 3. For this reason, generation | occurrence | production of the malfunction accompanying the reverse thrust force loaded on the expander 3 can be avoided.

  As described above, in the present embodiment, when the operation is stopped, the controller 20 sets the on-off valve 15 interposed in the circulation flow paths 6 a and 6 c between the evaporator 2 and the inlet side of the screw expander 3. On the other hand, the pressure equalizing valve 16 and the expander bypass valve 18 are opened after the working medium pump 5 is stopped. For this reason, the pressure of the circulation channels 6 a and 6 c extending from the evaporator 2 to the inlet side of the screw expander 3 (that is, the pressure in the circulation channel before and after the on-off valve 15) is the outlet side of the screw expander 3. Becomes substantially equal to the pressure in the circulation flow path 6b. As a result, it is possible to substantially stop the operation of the power generator 1 at an early stage after the stop of the working medium flow, and the pressure on the upstream side (inlet side) and the downstream side (outlet side) of the screw expander 3. It is possible to avoid the occurrence of a state in which the level of the pressure is reversed. Therefore, it is possible to avoid the occurrence of problems associated with the reverse thrust force applied to the screw expander 3. At the time of start-up, the open / close valve 15 is opened while the open pressure equalization valve 16 and the expander bypass valve 18 are closed, so that the working medium pump 5 is driven to resume the circulation of the working medium (binary power generation). When the apparatus 1 is restarted), it is possible to prevent the screw expander 3 from rapidly accelerating.

(Second Embodiment)
FIG. 4 shows a power generator 1a according to the second embodiment of the present invention. In the following description of the embodiment, the same constituent elements as those of the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In addition to the configuration of the power generation device 1 of the first embodiment, the power generation device 1a of the second embodiment includes a pressure sensor (evaporation pressure sensor) 21 provided in the flow path 6a between the evaporator 2 and the on-off valve 15. In other points, the configuration is the same as that of the power generation device 1 described above. The evaporation pressure sensor 21 detects the pressure of the working medium on the downstream side of the evaporator 2 in the circulation flow path 6, and the evaporation pressure sensor 21 can detect the evaporation pressure in the evaporator 2. Yes.

  As will be described later, the controller 20 of the power generator 1a is configured to open the pressure equalizing valve 16 when the pressure Pv detected by the evaporation pressure sensor 21 is equal to or higher than a predetermined upper limit value Pv_H when the operation is stopped. ing.

  Next, the contents of control of the power generator 1a will be described with reference to FIGS. FIG. 5 is a flowchart showing the control operation of the power generator 1a at the time of startup. FIG. 6 is a flowchart showing the control operation of the power generator 1a when the operation is stopped.

  First, the content of control of the power generator 1a at the time of starting is demonstrated. The control operation of the power generation device 1a at the time of start-up is often in common with the control operation at the time of start-up of the power generation device 1 of the first embodiment, but a start command is output as shown in FIG. It differs from the first embodiment in that a branch processing step (step St7) is provided after step St1). In the branch processing step (step St7), it is determined whether or not the pressure Pv detected by the evaporation pressure sensor 21 is equal to or higher than a predetermined upper limit value Pv_h.

  If it is determined YES in this branch processing step (step St7), that is, if it is determined that the pressure Pv is equal to or higher than the predetermined upper limit value Pv_h, the expander bypass valve 18 is opened and the pressure equalizing valve 16 is opened. (Step St2), and thereafter, the same processing as that of the power generation device 1 of the first embodiment is performed. On the other hand, if NO is determined in the branch processing step (step St7), that is, if it is determined that the pressure Pv is smaller than the predetermined upper limit value Pv_h, the opening / closing is immediately performed without performing steps St2 and St3. The valve 15 is opened (step St4).

  When the operation is stopped, the control operation of the power generation device 1a of the second embodiment is often in common with the control operation of the power generation device 1 of the first embodiment, but in the second embodiment, it is shown in FIG. As shown in the figure, the second embodiment is different from the first embodiment in that a branch processing step (step St16) is provided after the step (step St14) of measuring a predetermined time by the timer. In the branch processing step (step St16), it is determined whether or not the pressure Pv detected by the evaporation pressure sensor 21 is equal to or higher than a predetermined upper limit value Pv_h.

  If it is determined YES in this branch processing step (step St16), that is, if it is determined that the pressure Pv is equal to or higher than the predetermined upper limit value Pv_h, the pressure equalizing valve 16 is opened (step St15). On the other hand, if NO is determined in the branch process step (step St16), that is, if it is determined that the pressure Pv is smaller than the predetermined upper limit value Pv_h, the process returns to this branch process step without shifting to step St15. .

  In the second embodiment, when it is determined that the pressure Pv is lower than the predetermined upper limit value Pv_h at the time of startup, the on-off valve 15 is immediately opened (step St4) without performing steps St2 and St3. Can be started quickly. Further, when the operation is stopped, while the pressure Pv is smaller than the predetermined upper limit value Pv_h, the process is not shifted to step St15, and this branching process step is repeated, so that the pressure equalizing valve 16 is not activated. There is no need to open it up. That is, since the load of the reverse thrust force is caused by opening the pressure equalizing valve 16, the generation of the reverse thrust force applied to the screw expander 3 is suppressed by not opening the pressure equalizing valve 16 unnecessarily. The effect of avoiding the accompanying trouble can be further ensured.

(Third embodiment)
FIG. 7 shows a power generator 1b according to a third embodiment of the present invention.

  The power generation device 1b of the third embodiment is common in many respects to the configuration of the power generation device 1a of the second embodiment. However, in addition to the configuration of the power generation device 1a described above, a discharge pressure sensor 22 is provided. Different from the second embodiment. The discharge pressure sensor 22 is provided in the flow path 6 b between the expander 3 and the condenser 4 in the circulation flow path 6.

  As will be described later, the calculation unit 20b of the controller 20 has a predetermined pressure difference ΔP between the pressure Pv detected by the evaporation pressure sensor 21 and the pressure Pd detected by the discharge pressure sensor 22 when the operation is stopped. The pressure equalizing valve 16 is configured to open when the value is equal to or greater than a predetermined value ΔPH.

  Next, the contents of control of the power generator 1b will be described with reference to FIGS. FIG. 8 is a flowchart showing the control operation of the power generator 1b at the time of startup. FIG. 9 is a flowchart showing the control operation of the power generator 1b when the operation is stopped.

  First, the contents of control of the power generation device 1b at the time of activation will be described. The control operation of the power generation device 1b at the time of start-up is often in common with the control operation at the time of start-up of the power generation device 1a of the second embodiment, but as shown in FIG. It differs from 2nd Embodiment by the point (step St8) based on differential pressure | voltage (DELTA) P is provided instead of. The determination step (step St8) is a step that is executed after the output step (step St1) of the start command, and is the difference between the pressure Pv detected by the evaporation pressure sensor 21 and the pressure Pd detected by the discharge pressure sensor 22. In this step, it is determined whether or not the differential pressure ΔP is equal to or greater than a predetermined value ΔPH.

  If it is determined YES in this determination step (step St8), that is, if it is determined that the differential pressure ΔP is equal to or greater than the predetermined value ΔPH, the expander bypass valve 18 is opened and the pressure equalizing valve 16 is opened ( Step St2), and thereafter, the same processing as in the first and second embodiments is performed. On the other hand, if NO is determined in the determination step (step St8), that is, if it is determined that the differential pressure ΔP is smaller than the predetermined value ΔPH, steps St2 and St3 are not performed, and the on-off valve 15 is immediately turned on. Open (step St4).

  When the operation is stopped, the control operation of the power generation device 1b of the third embodiment is often in common with the control operation of the power generation device 1a of the second embodiment, but as shown in FIG. The second embodiment is different from the second embodiment in that a determination step (step St17) is provided after the step (step St14) of measuring a predetermined time. In the determination step (step St17), it is determined whether or not the differential pressure ΔP between the pressure Pv detected by the evaporation pressure sensor 21 and the pressure Pd detected by the discharge pressure sensor 22 is equal to or greater than a predetermined value ΔPH.

  If YES is determined in this determination step (step St17), that is, if it is determined that the differential pressure ΔP is equal to or greater than the predetermined value ΔPH, the pressure equalizing valve 16 is opened (step St15). On the other hand, if NO is determined in the determination step (step St17), that is, if it is determined that the differential pressure ΔP is smaller than the predetermined value PH, the process returns to this determination step without shifting to step St15.

  In the third embodiment, when it is determined that the differential pressure ΔP is smaller than the predetermined value ΔPH at the time of startup, the on-off valve 15 can be opened immediately without performing Steps St2 and St3 (Step S1). St4), activation can be speeded up. In addition, when the operation is stopped, while the pressure difference ΔP is determined to be smaller than the predetermined value PH, the determination step is not repeated and the determination step is repeated. There is no need to open it unnecessarily. That is, since the load of the reverse thrust force is caused by opening the pressure equalizing valve 16, the generation of the reverse thrust force applied to the screw expander 3 is suppressed by not opening the pressure equalizing valve 16 unnecessarily. The effect of avoiding the accompanying trouble can be further ensured.

  Here, another control example of the power generation device 1b according to the third embodiment will be described with reference to FIGS. FIG. 10 is a flowchart showing the control operation of the power generator 1b at the time of startup. FIG. 11 is a flowchart showing the control operation of the power generator 1b when the operation is stopped.

  At the time of start-up, as shown in FIG. 10, detection is performed by the evaporation pressure sensor 21 between the step of performing the counting process by the timer (step St3) and the step of performing the process of opening the on-off valve 15 (step St4). A second determination processing step (step St9) is provided in which it is determined whether or not the differential pressure ΔP between the generated pressure Pv and the pressure Pd detected by the discharge pressure sensor 22 is smaller than a predetermined value ΔPH. This is different from the flowchart shown in FIG.

  In a second determination process step (step St9) for determining whether or not the differential pressure ΔP between the pressure Pv detected by the evaporation pressure sensor 21 and the pressure Pd detected by the discharge pressure sensor 22 is smaller than a predetermined value ΔPH. If YES is determined, the process proceeds to a step (step St4) of performing a process of opening the on-off valve 15, and thereafter, the same process as the flowchart illustrated in FIG. 8 is performed. On the other hand, if it is determined NO in the second determination processing step (step St9), it means that “the expander bypass valve and the pressure equalizing valve are not open” or “the evaporation pressure sensor or the discharge pressure sensor is An alarm process (step St10) for transmitting an alarm “abnormal” to the display unit 11c of the controller 11 is performed.

  By executing this second determination processing step (step St9), the differential pressure ΔP between the pressure Pv detected by the evaporating pressure sensor 21 and the pressure Pd detected by the discharge pressure sensor 22 is determined from a predetermined value ΔPH at startup. Since the release valve 15 can be opened only in the case where the size of the screw expander is small, the screw expander 3 does not accelerate rapidly even when the circulation of the working medium is resumed (the binary power generation device 1b is restarted). This effect can be further ensured.

  When the operation is stopped, the same control as the control shown in FIG. 9 is executed as shown in FIG.

(Fourth embodiment)
FIG. 12 shows a power generator 1c according to a fourth embodiment of the present invention.

  The power generation device 1c according to the fourth embodiment is common in many respects to the configuration of the power generation device 1b according to the third embodiment. In addition to the configuration of the power generation device 1b described above, the heating medium supply channel 11 includes an opening / closing valve. Unlike the third embodiment in that a heating medium supply valve 23 is provided, one end of the expander bypass flow path 19 is not connected to the pressure equalization flow path 17 but the screw expander 3 and the oil separator 8. The third embodiment is different from the third embodiment also in that one of the pressure equalizing channels 17 is connected to the channel 6b between the two and the channel 6b.

  Next, the contents of control of the power generator 1c will be described with reference to FIGS. FIG. 13 is a flowchart showing the control operation of the power generator 1c at the time of startup. FIG. 14 is a flowchart showing the control operation of the power generator 1c when the operation is stopped.

  First, the contents of control of the power generation device 1c at the time of activation will be described. The control operation of the power generation device 1c at the time of start-up is often in common with the control operation at the time of start-up of the power generation device 1b of the third embodiment, but as shown in FIG. 13, the step of opening the on-off valve 15 It differs from 3rd Embodiment by the point (step St20) which performs the process which open | releases the heating-medium supply valve 23 is performed before (step St4).

  Next, the details of the control of the power generation device 1c when the operation is stopped will be described. Although the control operation of the power generation device 1c at the time of operation stop is common in common with the control operation at the time of operation stop of the power generation device 1b of the third embodiment, a stop command is output as shown in FIG. The third embodiment is different from the third embodiment in that after the processing step (step St11), a step (step St21) of performing a process of closing the heating medium supply valve 23 is executed.

  As described above, when the operation is stopped, the heating medium supply valve 23 is closed to first stop the supply of the heating medium to the evaporator 2, and the temperature of the evaporator 2 is increased, which is detected by the evaporation pressure sensor 21. By suppressing the increase in the pressure Pv, the power generation device 1c can be smoothly stopped.

  Further, by directly connecting one of the pressure equalization channels 17 to the condenser 4, it is possible to prevent the working medium from returning to the oil separator 8 through the pipe. That is, when the power generation device 1 is started, the heating medium supply valve 23 is opened (step St20), and when the heating medium flows into the evaporator 2, the working medium vaporized in the evaporator 2 (in liquid state) Is also moved from the evaporator 2 to the condenser 4, but at this time, the working medium can be prevented from moving from the evaporator 2 to the oil separator 8.

1, 1a, 1b Power generation device power generation cycle 2 Evaporator 3 Screw expander 4 Condenser 5 Working medium pump 6 Circulating flow path 7 Generator 8 Oil separator 9 Oil pump 10 Oil supply path 11 Heating medium supply path 12 Heating medium discharge Flow path 13 Cooling medium supply flow path 14 Cooling medium discharge flow path 15 On-off valve 16 Pressure equalizing valve 17 Pressure equalizing flow path 18 Expander bypass valve 19 Expander bypass flow path 20 Controller 21 Evaporating pressure sensor 22 Discharge pressure sensor 23 Heating medium supply valve

Claims (4)

A circulation channel through which the working medium flows;
An evaporator for evaporating the working medium by a heating medium supplied from the outside;
An expander that rotates the generator by introducing the evaporated working medium;
A condenser in which the working medium discharged from the expander is introduced and the working medium is condensed by a cooling medium supplied from the outside;
A working medium pump that re-feeds the working medium condensed in the condenser to the evaporator;
A power generation device comprising:
An on-off valve disposed at a site between the evaporator and the inlet side of the expander in the circulation channel;
A pressure equalizing valve, and in the circulation flow path, a pressure equalizing flow path capable of communicating a portion between the on-off valve and the evaporator and a portion between the outlet side of the expander and the condenser; ,
An expander bypass valve is provided, and in the circulation channel, a portion between the on-off valve and the inlet side of the expander and a portion between the outlet side of the expander and the condenser can be communicated An expander bypass channel,
When the operation is stopped, control is performed to close the open / close valve and open the expander bypass valve and the pressure equalizing valve after the working medium pump is stopped. A controller that performs control to close the expander bypass valve and the pressure equalizing valve before driving the pump;
A power generator characterized by comprising:   2. The control according to claim 1, wherein when the operation is stopped, control is performed to open the expander bypass valve and the pressure equalizing valve when a predetermined time has elapsed after the working medium pump is stopped. Power generation device. In the circulation channel, an evaporation pressure sensor is provided between the evaporator and the on-off valve,
When the operation is stopped, control is performed to open the expander bypass valve and the pressure equalizing valve when the pressure detected by the evaporation pressure sensor after the stop of the working medium pump exceeds a predetermined upper limit value. The power generation device according to claim 1, wherein the power generation device is performed. The circulation flow path is provided with an evaporation pressure sensor disposed between the evaporator and the on-off valve, and a discharge pressure sensor disposed between the expander and the condenser.
At the time of stopping the operation, when the pressure difference between the pressure detected by the evaporation pressure sensor and the pressure detected by the discharge pressure sensor after the working medium pump is stopped becomes equal to or higher than a predetermined value. The power generator according to claim 1, wherein control is performed to open the expander bypass valve and the pressure equalizing valve.

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