JP7201562B2 - GENERATING DEVICE AND CONTROL METHOD OF GENERATING DEVICE - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power generator and a control method for the power generator.

A power generator has been developed in which a working medium vaporized by heat exchange with a heating medium in an evaporator is supplied to an expander connected to a generator, and the expansion of the working medium is used to drive the expander and the generator. (See Patent Document 1). In addition to an evaporator, a generator, and an expander, the power generator includes a condenser that condenses the working medium expanded by the expander, and a medium pump that delivers the condensed working medium to the evaporator. The amount of working medium flowing from the medium pump to the evaporator is adjusted so that the degree of superheat of the working medium supplied from the evaporator to the expander approaches a predetermined target value.

JP 2014-47632 A

When the temperature of the heating medium is high, the superheat of the working medium increases and can exceed the desired value. At this time, the amount of working medium flowing into the evaporator is increased in order to lower the degree of superheat. As the amount of working medium flowing into the evaporator increases, the amount of working medium that evaporates under heat exchange with the hot heating medium also increases. As a result of the increase in the amount of evaporation of the working medium, the internal pressure of the line that guides the working medium from the evaporator to the expander increases. If the inflow to the evaporator is increased when the pipe pressure has already reached a high value, the pipe pressure will become excessively high.

An object of the present invention is to provide a power generation technique that achieves a high amount of power generation without excessively increasing the pressure inside the pipe.

In the power generation device according to one aspect of the present invention, the working medium sent out by the medium pump is passed through the evaporator, the expander, and the condenser in this order, and then returned to the medium pump. a heat recovery unit that recovers heat from the heating medium supplied to the evaporator; a generator driven by the expander; a superheat degree determination process for determining whether or not the degree of superheat of the working medium in the pipe is within a predetermined control target range; and the rotational speed of the medium pump. is greater than a predetermined rotation speed threshold, a determination processing unit that executes a determination processing result of the determination processing unit, the working medium to the evaporator and an inflow control unit that controls the inflow of the In the upper limit determination process, when a determination result is obtained that the pipe internal pressure is equal to or less than the upper limit threshold value, the inflow control unit determines that the degree of superheat is the above The inflow is controlled so as to fall within the control target range. In the upper limit determination process, when a determination result is obtained that the pipe internal pressure exceeds the upper limit threshold, the inflow control unit reduces the inflow so that the pipe internal pressure is equal to or lower than the upper limit threshold. After reducing the degree of superheat, the inflow is controlled based on the determination result of the degree-of-superheat determination process so that the degree of superheat falls within the control target range. In the upper limit determination process, a determination result is obtained that the pipe internal pressure is equal to or less than the upper threshold, and in the rotational speed determination process, it is determined that the rotational speed of the medium pump is equal to or less than the rotational speed threshold. When the determination result is obtained, the inflow control unit controls the inflow amount based on the determination result of the superheat degree determination process so that the degree of superheat falls within the control target range. In the rotational speed determination process, when a determination result is obtained that the rotational speed of the medium pump exceeds the rotational speed threshold, the inflow control unit adjusts the rotational speed of the medium pump to the rotational speed Decrease the inflow by reducing it to a value below a number threshold .

According to the above configuration, when it is determined that the pipe internal pressure exceeds the upper threshold, the inflow control unit controls the amount of inflow of the working medium into the evaporator so that the pipe internal pressure is equal to or lower than the upper threshold. reduce Therefore, the pressure inside the pipe does not become excessively large.

The control of the inflow amount based on the determination result of the degree-of-superheat determination process is performed under the condition that the pipe internal pressure is equal to or lower than the upper limit threshold. Therefore, even if the inflow amount is increased as a result of controlling the inflow amount based on the determination result of the superheat degree determination process, the pipe internal pressure only increases by a value equal to or less than the upper threshold value, and is unlikely to take an excessively large value. Therefore, the inflow amount can be increased and the evaporation amount of the working medium in the evaporator can be increased without excessively increasing the pressure in the pipe. As a result of the increased evaporation of the working medium, the power output of the generator increases. That is, a high power generation amount can be obtained without excessively increasing the pressure in the pipe.

The superheat degree determination process is performed after the upper limit determination process. If the inflow amount control based on the superheat degree determination process is performed before the upper limit determination process, the inflow amount control based on the superheat degree determination process may be performed under a state where the pipe pressure is already high. . In the degree-of-superheat determination process, if the determination result indicates that the degree of superheat exceeds the upper limit of the target control range, the inflow of the working medium into the evaporator is increased to keep the degree of superheat within the target control range. . In this case, it is assumed that the pressure inside the pipe will further increase and take an excessively high value. On the other hand, if the upper limit judgment process is performed before the superheat degree judgment process, the pipe internal pressure is adjusted to be equal to or lower than the upper limit threshold, and then the degree of superheat is adjusted. is prevented. Even if it is determined in the upper limit determination process that the in-pipe pressure is equal to or lower than the upper threshold, the in-pipe pressure may take an excessively high value if the rotation speed of the medium pump continues to be high. . According to the above configuration, when it is determined in the rotation speed determination process that the rotation speed of the medium pump exceeds the rotation speed threshold value, the inflow control unit reduces the rotation speed of the medium pump to the rotation speed Reduce to a value below the threshold. As a result, the pipe internal pressure is prevented from taking an excessively high value.

With respect to the above configuration, the determination processing unit may further execute a lower limit determination process for determining whether or not the pipe internal pressure is below a predetermined lower limit threshold. When the pipe internal pressure is within the pressure range defined by the lower limit threshold value and the upper limit threshold value, the inflow control unit determines that the degree of superheat is the control target based on the determination result of the degree-of-superheat determination process. The inflow rate may be controlled so as to fall within a range. When the pipe internal pressure is outside the pressure range, the inflow control unit adjusts the inflow so that the pipe internal pressure falls within the pressure range, and then adjusts the determination result of the superheat degree determination process. Based on, the inflow may be controlled such that the degree of superheat falls within the control target range.

According to the above configuration, when the pipe internal pressure is outside the pressure range defined by the lower limit threshold and the upper limit threshold, the inflow control unit adjusts the inflow so that the pipe internal pressure is within the pressure range. Therefore, the in-pipe pressure neither takes an excessively high value nor takes an excessively low value. When the pipe internal pressure is lower than the lower limit threshold, the inflow control unit increases the inflow of the working medium to the evaporator in order to keep the pipe internal pressure within the pressure range. As a result, the power output from the generator driven by the expander also increases.

Control of the inflow amount based on the determination result in the superheat degree determination process is performed when the pipe internal pressure is within the pressure range. That is, when the inflow amount is controlled based on the determination result in the degree-of-superheat determination process, the pipe internal pressure exceeds the lower limit threshold. Even if the inflow is reduced as a result of the control of the inflow based on the determination result in the superheat degree determination process, the pipe internal pressure only decreases from a value equal to or higher than the lower limit threshold, and is unlikely to take an excessively small value. Therefore, the driving force of the expander is kept above a certain level, and the power generation amount from the generator driven by the expander is also kept above a certain level.

In the power generator according to another aspect of the present invention, the working medium sent out by the medium pump is passed through the evaporator, the expander, and the condenser in this order, and then returned to the medium pump. a heat recovery unit for recovering heat from the heating medium supplied to the vessel; a generator driven by the expander; and the heating medium for exchanging heat with the working medium in the evaporator to evaporate the working medium. a temperature determination process for determining whether or not the temperature of the heating medium exceeds a predetermined temperature threshold; and a degree-of-superheat determination process for determining whether or not the degree of superheat is within the target control range by increasing the control target range of the degree of superheat of the working medium in the conduit connecting the evaporator and the expander. and a determination processing unit that executes the above, and based on the result of the degree-of-superheat determination processing, the amount of inflow of the working medium into the evaporator is adjusted so that the degree of superheat of the working medium falls within the control target range. and an inflow control unit for controlling.

According to the above configuration, when it is determined in the temperature determination process that the temperature of the heating medium exceeds the temperature threshold, the control target range for the degree of superheat of the working medium is raised. When the upper limit has a high value, the superheat is less likely to exceed the upper limit. That is, it becomes difficult to perform control for increasing the inflow when the degree of superheat exceeds the upper limit. On the other hand, when the lower bound has a high value, the degree of superheat tends to fall below the lower bound. That is, it becomes easier to perform control to reduce the inflow when the degree of superheat falls below. Therefore, when it is determined that the temperature of the heating medium exceeds the temperature threshold, an increase in the amount of working medium flowing into the evaporator is suppressed.

Setting the control target range described above is useful when the temperature of the heating medium changes greatly. As the temperature of the heating medium rises, the amount of evaporation of the working medium in the evaporator increases, and the pressure inside the pipe connecting the evaporator and the expander tends to increase. However, when the temperature of the heating medium exceeds the temperature threshold, an increase in the amount of inflow is suppressed as described above, so an increase in the amount of evaporation of the working medium in the evaporator is also suppressed. Therefore, the pressure inside the pipe is unlikely to become excessively high.

In the power generator according to another aspect of the present invention, the working medium sent out by the medium pump is passed through the evaporator, the expander, and the condenser in this order, and then returned to the medium pump. a heat recovery unit for recovering heat from the heating medium supplied to the vessel; a generator driven by the expander; and the heating medium for exchanging heat with the working medium in the evaporator to evaporate the working medium. a temperature determination process for determining whether or not the temperature of the heating medium exceeds a predetermined temperature threshold; Determining whether the degree of superheat of the working medium in the conduit connecting the evaporator and the expander is within the first control target range of the degree of superheat, and determining whether the temperature of the heating medium exceeds the temperature threshold and a superheat degree determination process for determining whether or not the degree of superheat falls within a second control target range higher than the first control target range when a determination result is obtained that the a determination processing unit, when the determination result that the temperature of the heating medium is equal to or lower than the temperature threshold value is obtained, the degree of superheat is within the first control target range based on the result of the degree-of-superheat determination process; When the determination result that the temperature of the heating medium exceeds the temperature threshold is obtained, the degree of superheat is reduced to the and an inflow control unit that controls the inflow amount so as to fall within a second control target range.

In a control method according to still another aspect of the present invention, a working medium sent by a medium pump is passed through an evaporator, an expander, and a condenser in this order, and then circulated back to the medium pump. It can be used to control a generator that drives a generator using a motor. The control method includes executing an upper limit determination process for determining whether or not the internal pressure of a line connecting the evaporator and the expander exceeds a predetermined upper limit threshold; and executing a rotation speed determination process for determining whether or not the rotation speed threshold value is exceeded; and when a determination result is obtained in the upper limit determination process that the pressure in the pipe is equal to or lower than the upper threshold, the degree of superheat of the working medium in the pipe is the above Controlling the inflow amount of the working medium into the evaporator so as to fall within the control target range, and in the upper limit determination process, obtaining a determination result that the pipe internal pressure exceeds the upper limit threshold. sometimes controlling the inflow so that the degree of superheat falls within the control target range after reducing the inflow so that the pipe internal pressure is equal to or lower than the upper limit threshold ; , a determination result is obtained that the pipe internal pressure is equal to or less than the upper limit threshold value, and in the rotational speed determination process, a determination result is obtained that the rotational speed of the medium pump is equal to or less than the rotational speed threshold value. and controlling the inflow amount so that the degree of superheat falls within the control target range based on the determination result of the degree-of-superheat determination process; reducing the rotation speed of the medium pump to a value equal to or lower than the rotation speed threshold value to reduce the inflow when it is determined that the rotation speed exceeds the rotation speed threshold value. I have.

In a control method according to still another aspect of the present invention, a working medium sent by a medium pump is passed through an evaporator, an expander, and a condenser in this order, and then circulated back to the medium pump. It can be used to control a generator that drives a generator using a motor. The control method includes executing temperature determination processing for determining whether or not the temperature of a heating medium that exchanges heat with the working medium in the evaporator and evaporates the working medium exceeds a predetermined temperature threshold; In the temperature determination process, when it is determined that the temperature of the heating medium exceeds the temperature threshold, increasing a control target range and executing superheat degree determination processing for determining whether or not the degree of superheat is within the control target range; and controlling the flow rate of the working medium into the evaporator so that the degree of superheat falls within the control target range.

The power generation technology described above can achieve high power generation without excessively increasing the pressure in the pipe.

1 is a schematic diagram of a power generator according to a first embodiment; FIG. 5 is a schematic flow chart representing exemplary operations of a determination processing unit and an inflow control unit of a power generation device; 4 is a schematic flow chart representing another exemplary operation of the determination processing unit and the inflow control unit; FIG. 3 is a schematic diagram of a power generator that performs rotation speed determination processing; FIG. 4 is a schematic flow chart showing an exemplary operation of a determination processing unit that performs rotation speed determination processing; FIG. It is the schematic of the electric power generating apparatus of 2nd Embodiment. 4 is a conceptual graph of determination criteria used in superheat degree determination processing of the determination processing unit; 4 is a schematic flow chart representing exemplary operations of a determination processor and an inflow controller; 4 is a conceptual graph of criteria used in superheat degree determination processing.

<First embodiment>
FIG. 1 is a schematic diagram of a power generator 100 of the first embodiment. A power generator 100 will be described with reference to FIG.

The power generator 100 includes a heat recovery unit 110 configured to recover heat from a heating medium having a temperature higher than that of the working medium using the working medium, and a power generator 120 .

Heat recovery unit 110 is configured to perform a Rankine cycle. The heat recovery unit 110 includes a medium pump 111 that discharges a working medium, and a circulation path 112 that is connected to a discharge port and a suction port of the medium pump 111 and forms a circulation path through which the working medium circulates. . The heat recovery section 110 further includes an evaporator 113 , an expander 114 and a condenser 115 arranged on the circuit 112 . The evaporator 113, the expander 114 and the condenser 115 are arranged so that the working medium sent out from the medium pump 111 sequentially passes through them.

The evaporator 113 is configured to heat-exchange the working medium with the heating medium and recover the heat of the heating medium to the working medium. The heating medium is a sufficiently hot fluid to vaporize the working medium and is supplied from outside the power plant 100 . The heating medium may be exhaust gas from the engine or other fluid having a temperature high enough to vaporize the working medium.

The expander 114 sucks in the working medium vaporized by the evaporator 113, and the internal rotor rotates due to the expansion action of the working medium. The rotor of expander 114 is connected to and drives generator 120 .

The condenser 115 is configured to heat-exchange the working medium flowing out of the expander 114 with the cooling medium supplied from the outside of the power generation device 100 . As a cooling medium, a fluid (eg seawater, water, coolant, etc.) with a sufficiently low temperature to liquefy the working medium is used.

The medium pump 111 increases the pipe internal pressure of the pipe 116 (part of the above-described circulation 112) connecting the evaporator 113 and the expander 114 (that is, the circulation 112 from the outlet of the evaporator 113 to the inlet of the expander 114). ) and the degree of superheat of the working medium flowing through the conduit 116 . The power generator 100 includes an inflow control section 131 , a pressure detection section 132 , a temperature detection section 133 and a determination processing section 134 as control-related parts used to control the medium pump 111 .

Both the pressure detector 132 and the temperature detector 133 are attached to the pipeline 116 . As the pressure detection unit 132, a pressure sensor capable of detecting the pressure inside the pipe line 116 can be used. A temperature sensor capable of detecting the temperature of the working medium flowing through the conduit 116 can be used as the temperature detection unit 133 .

The determination processing unit 134 connects the pressure detection unit 132 and the temperature detection unit 133 to the pressure detection unit 132 and the temperature detection unit 133 so that the detection signals representing the pipe pressure and the temperature of the working medium are received from the pressure detection unit 132 and the temperature detection unit 133 respectively. It is connected to the. The determination processing section 134 is configured to perform predetermined determination processing using information represented by detection signals from the pressure detection section 132 and the temperature detection section 133 . In addition, the determination processing section 134 is configured to transmit the determination result obtained from the determination processing to the inflow control section 131 .

The inflow control unit 131 is configured to determine the operation content of maintaining, increasing, or decreasing the rotation speed of the medium pump 111 based on the determination result transmitted from the determination processing unit 134. It is The inflow controller 131 is configured to generate a drive signal so that the medium pump 111 operates according to the determined operation details. That is, the inflow control section 131 is configured to control the medium pump 111 based on the determination result obtained from the determination processing section 134 . Through control over the medium pump 111, the inflow of working medium to the evaporator 113 is controlled. The determination processing unit 134 and the inflow control unit 131 may be formed using a CPU (Central Processing Unit) that executes a program that determines the above-described determination processing and operation details, and a signal generation circuit that generates a drive signal.

The working medium flow within the power plant 100 is described below.

A liquid-phase working medium is pumped by a medium pump 111 to an evaporator 113 . The working medium flows into the evaporator 113 and exchanges heat with the heating medium. As a result, the working medium vaporizes. The vaporized working medium flows into the expander 114 and expands within the expander 114 . Expansion of the working medium within the expander 114 results in rotation of the rotor of the expander 114 and a generator 120 connected to the rotor produces electrical power. The working medium used for work in expander 114 flows from expander 114 into condenser 115 . The working medium exchanges heat with the cooling medium in the condenser 115 and returns to the liquid phase. The liquid-phase working medium is sucked by the medium pump 111 and then sent to the evaporator 113 again.

The operations of the determination processing unit 134 and the inflow control unit 131 will be described below with reference to FIGS. 1 and 2. FIG. FIG. 2 is a schematic flow chart representing exemplary operations of the determination processing unit 134 and the inflow control unit 131. As shown in FIG.

For the determination processing of the determination processing unit 134, an upper limit threshold is set for the pressure inside the pipeline 116. FIG. The upper limit threshold is set to a value smaller than the maximum internal pressure that the pipeline 116 allows so that the pipeline internal pressure does not exceed the withstand pressure capability of the pipeline 116 . Preferably, the difference between the upper threshold and the maximum internal pressure of the line 116 is determined by considering the maximum value that the intra-line pressure that increases beyond the upper threshold is expected to take.

In addition, a control target range is set for the degree of superheat of the working medium flowing through line 116 . For example, the lower limit of the control target range is the lower limit allowable value of the power generation amount of the generator 120 (lower limit value allowed for the power generation amount or the rotation speed of the generator 120 that allows the generator 120 to stably generate power). It may take a predetermined value set so as not to fall below the lower limit of the possible rotation speed). The upper limit of the control target range is a predetermined value set in consideration of the upper limits of the capabilities of the expander 114 and the generator 120 .

The determination processing unit 134 waits for reception of detection signals from the pressure detection unit 132 and the temperature detection unit 133 (step S110). When the determination processing unit 134 receives the detection signals, it calculates the degree of superheat of the working medium from the pipe internal pressure and the temperature of the working medium indicated by these detection signals (step S120). The determination processing unit 134 then executes upper limit determination processing using the above-described upper limit threshold (step S130). Regarding the upper limit determination process, the determination processing unit 134 compares the pipe pressure indicated by the detection signal from the pressure detection unit 132 with the upper limit threshold, and determines whether or not the pipe pressure exceeds the upper limit threshold. If the pipe pressure exceeds the upper limit threshold (step S130: Yes), the determination result indicating that the pipe pressure exceeds the upper limit threshold is transmitted from the determination processing unit 134 to the inflow control unit 131. In this case, the inflow control unit 131 determines to reduce the rotation speed of the medium pump 111 (step S150). The inflow controller 131 generates a drive signal so that the rotation speed of the medium pump 111 decreases. A drive signal is output from the inflow controller 131 to the medium pump 111, and the medium pump 111 rotates at a reduced number of revolutions. When the rotation speed of the medium pump 111 is reduced, the amount of working medium flowing into the evaporator 113 and the amount of vaporization of the working medium in the evaporator 113 are reduced, and the pressure in the pipe 116 is reduced. After that, step S110 is executed again. A processing loop consisting of steps S110, S120, S130 and S150 is repeated until it is determined in the upper limit determination processing of step S130 that the pipe internal pressure does not exceed the upper limit threshold.

If the pipe internal pressure does not exceed the upper limit threshold (step S130: No), the determination processing unit 134 executes the superheat degree determination process using the above-described control target range (step S140). Regarding the degree-of-superheat determination process, determination processing unit 134 compares the lower and upper limits of the above-described target control range with the degree of superheat calculated in step S120, and the degree of superheat of the working medium in conduit 116 is within the target control range. It is determined whether or not the If the degree of superheat is between the lower limit and the upper limit of the control target range (step S140: Yes), the determination result that the degree of superheat is within the control target range is transmitted from the determination processing unit 134 to the inflow control unit 131 . In this case, the inflow control unit 131 determines to maintain the rotational speed of the medium pump 111 (step S160). The inflow controller 131 generates a drive signal to maintain the rotation speed of the inflow controller 131 . A drive signal is output from the inflow control unit 131 to the medium pump 111, and the medium pump 111 discharges the working medium to the evaporator 113 without changing the rotational speed. As a result, the superheat of the working medium in line 116 remains within the control target range. After that, step S110 is executed again.

If the degree of superheat is below the lower limit of the control target range (step S140: No, bottom), the determination result that the degree of superheat is below the lower limit of the control target range is sent from the determination processing unit 134 to the inflow control unit 131. is transmitted to In this case, the inflow control unit 131 determines to reduce the rotation speed of the medium pump 111 (step S150). The inflow controller 131 generates a drive signal so that the rotation speed of the medium pump 111 decreases. A drive signal is output from the inflow controller 131 to the medium pump 111, and the medium pump 111 rotates at a reduced number of revolutions. When the rotation speed of the medium pump 111 is reduced, the amount of working medium flowing from the medium pump 111 to the evaporator 113 is reduced, so the degree of superheat of the working medium in the conduit 116 is increased. As a result, the degree of superheat of the working medium falls within the control target range. After that, step S110 is executed again.

If the degree of superheat exceeds the upper limit of the control target range (step S140: No, above), the determination result that the degree of superheat exceeds the upper limit of the control target range is sent from the determination processing unit 134 to the inflow control unit 131. is transmitted to In this case, the inflow control unit 131 determines to increase the rotation speed of the medium pump 111 (step S170). The inflow controller 131 generates a drive signal to increase the rotation speed of the inflow controller 131 . A drive signal is output from the inflow controller 131 to the medium pump 111, and the medium pump 111 rotates at the increased number of revolutions. Since the inflow of working medium from the medium pump 111 to the evaporator 113 increases, the degree of superheat of the working medium in the line 116 decreases. As a result, the degree of superheat of the working medium falls within the control target range. After that, step S110 is executed again.

As described above, the processing loop consisting of steps S110, S120, S130, and S150 is repeated until it is determined in the upper limit determination processing of step S130 that the pipe internal pressure does not exceed the upper limit threshold. Therefore, the degree-of-superheat determination processing in step S140 is performed under the condition that the pipe internal pressure does not exceed the upper limit threshold. That is, the control of the inflow amount of the working medium based on the degree-of-superheat determination process is performed under the condition that the pipe internal pressure does not exceed the upper limit threshold. When the inflow amount of the working medium is controlled based on the degree-of-superheat determination process, even if the inflow amount to the evaporator 113 is increased, the pipe internal pressure only increases from a value equal to or lower than the upper threshold value. is not overly large.

The lower limit of the control target range used in the superheat degree determination process is set so that the amount of power generated by generator 120 does not fall below the lower limit allowable value. Therefore, when the degree of superheat is equal to or higher than the lower limit of the control target range, generator 120 can generate power exceeding the lower limit allowable value.

When the degree of superheat is increased under the condition that the degree of superheat is below the lower limit of the control target range, the power generation amount of the generator 120 increases. According to the control described with reference to FIG. 2, when the degree of superheat is below the lower limit of the control target range, step S150 is executed to reduce the rotation speed of the medium pump 111 (that is, the evaporator 113 the inflow of working medium to the is reduced). As a result, the degree of superheat of the working medium flowing out of the evaporator 113 is increased. As a result of the increased superheat, the power output of generator 120 increases. Therefore, the power generation amount of the generator 120 can be maintained at a relatively high level.

The upper limit determination process is performed before the superheat degree determination process. If the superheat degree determination process is performed before the upper limit determination process, the control of the inflow amount of the working medium based on the superheat degree determination process can be performed under the condition that the pipe internal pressure has already reached a high value. . In this case, if the degree of superheat is determined to be higher than the upper limit of the control target range in the degree of superheat determination process, the inflow of the working medium to the evaporator 113 is increased, further increasing the pressure in the pipe. . On the other hand, according to the control described with reference to FIG. 2, the upper limit determination process is performed before the superheat degree determination process. Therefore, when the pipe pressure exceeds the upper threshold, the working medium flowing into the evaporator 113 is reduced under a processing loop consisting of steps S110, S120, S130 and S150, thereby reducing the pipe pressure. Since the inflow of the working medium is controlled based on the degree-of-superheat determination process after the pressure in the pipe is reduced, the pressure in the pipe does not take an excessively high value.

In the determination process shown in FIG. 2, the pipe internal pressure is compared with the upper limit threshold. However, the pipe pressure may additionally be compared with a predetermined lower threshold to determine whether the pipe pressure is below the lower threshold (lower limit determination process). The lower limit threshold may be set so that the power generation amount of the generator 120 does not fall below the lower limit allowable value even if the pipe pressure falls below the lower limit threshold. Additionally, the calculation of the degree of superheat may be performed when the degree-of-superheat determination process is performed. FIG. 3 is a schematic flow chart showing the determination process with these changes.

The lower limit determination process (step S131) is performed together with the upper limit determination process by the determination processing unit 134 after step S110. In the lower limit determination process, if the determination result that the pipe pressure is below the lower limit threshold is obtained (step S131: No, lower limit threshold>pipe pressure), the determination result is sent from the determination processing unit 134 to the inflow control unit 131. output. The inflow control unit 131 increases the rotation speed of the medium pump 111 based on the determination result (step S170).

In the lower limit determination process, the determination result that the pipe pressure is equal to or higher than the lower limit threshold is obtained, and in the upper limit determination process, the determination result that the pipe pressure is equal to or lower than the upper limit threshold is obtained (Step S131: Yes), calculation of the degree of superheat (step S132), and degree-of-superheat determination processing (step S140) are performed. The computation processing of the degree of superheat in step S132 is the same as in step S120 described with reference to FIG.

Since the lower limit determination process is performed in addition to the upper limit determination process, when it is determined in the lower limit determination process that the pipe internal pressure is lower than the lower limit threshold value, the inflow control unit 131 reduces the rotation speed of the medium pump 111 to is increased. As a result, the amount of working medium flowing from the medium pump 111 to the evaporator 113 increases. An increase in the inflow of working medium results in an increase in power generation.

The calculation of the degree of superheat is performed when the conditions for performing the degree-of-superheat determination processing (that is, the condition that the pressure in the pipe is within the pressure range equal to or greater than the lower limit threshold value and equal to or less than the upper limit threshold value) are met. When the degree-of-superheat determination process is not performed, the degree of superheat is not calculated. As a result, unnecessary calculation processing is reduced, and the calculation load of the determination processing unit 134 is reduced.

In addition to the upper limit determination process, the determination processing unit 134 may determine whether or not the rotation speed of the medium pump 111 exceeds a predetermined rotation speed threshold (rotation speed determination process). The rotational speed threshold is set in consideration of the expected maximum value when the rotational speed of the medium pump 111 increases beyond the rotational speed threshold. The rotational speed threshold is determined so that the pressure in the pipe does not exceed a predetermined value set below the withstand pressure capability of the pipe 116 even when the medium pump 111 rotates at the predicted maximum value. may A schematic diagram of the power generator 100 that performs the rotation speed determination process is shown in FIG. FIG. 5 shows a flowchart representing the operation of the determination processing section 134 including the rotation speed determination process. The rotational speed determination process will be described with reference to FIGS. 1 and 5. FIG.

When the determination processing unit 134 performs the rotation speed determination process, a rotation speed signal representing the rotation speed of the medium pump 111 is output to the determination processing unit 134 . The RPM signal may be generated by a speed detector 136 such as, for example, an encoder attached to the media pump 111 to detect the RPM of the media pump 111 . In this case, the rotational speed signal is output from the speed detector 136 to the determination processing section 134 .

The determination processing unit 134 receives the rotational speed signal together with the detection signals from the pressure detection unit 132 and the temperature detection unit 133 (step S111). After that, calculation of the degree of superheat (step S120) and upper limit determination processing (step S130) are sequentially executed. After the upper limit determination process, the rotational speed determination process is executed (step S133).

Regarding the rotation speed determination process, the determination processing unit 134 compares the rotation speed represented by the rotation speed signal with the rotation speed threshold. If the rotation speed of the medium pump 111 exceeds the rotation speed threshold (step S133: No), the determination result indicating that the rotation speed exceeds the rotation speed threshold is sent from the determination processing unit 134 to the inflow control unit 131. is transmitted to The inflow control unit 131 reduces the rotation speed of the medium pump 111 to a value equal to or lower than the rotation speed threshold based on the determination result (step S150), thereby reducing the inflow amount of the working medium from the medium pump 111 to the evaporator 113 . On the condition that the determination result that the rotation speed does not exceed the rotation speed threshold is obtained in the rotation speed determination process (step S133: Yes), the determination processing unit 134 performs the superheat degree determination process (step S140). to run.

When the rotation speed of the medium pump 111 exceeds the rotation speed threshold, even if the pipe pressure detected by the pressure detection unit 132 is low, the pipe pressure is expected to increase thereafter and exceed the upper limit threshold. However, when the rotational speed determination process is performed and the rotational speed of the medium pump 111 exceeds the rotational speed threshold value, the rotational speed is reduced, thereby preventing the pipe internal pressure from exceeding the upper limit threshold value. be.

In the series of processes shown in FIG. 5, the rotational speed determination process is performed after the upper limit determination process. However, the rotational speed determination process may be performed before the upper limit determination process, or may be performed simultaneously with the upper limit determination process.

In the series of processes shown in FIG. 5, the upper limit determination process (step S130) is performed. Alternatively, the upper limit determination process and the lower limit determination process (step S131) shown in FIG. 3 may be performed. good.

Regarding the above-described embodiment, the superheat degree determination process is performed after the upper limit determination process. However, the degree of superheat may be constantly monitored while the power generator 100 is in operation. As long as the control of the inflow amount of the working medium based on the superheat degree determination process is performed after the upper limit determination process, an excessive increase in the pipe internal pressure is suppressed as described above.

Regarding the above-described embodiments, the heat recovery section 110 may further include a superheater that further heats the working medium evaporated in the evaporator 113 .

As for the above-described embodiment, the speed detector 136 detects the rpm of the media pump 111 . However, the speed detector 136 may detect the inverter frequency of the motor driving the media pump 111 .

With respect to the above-described embodiments, the amount of working medium flowing into the evaporator 113 is regulated through control of the rotation speed of the medium pump 111 . In addition to controlling the rotational speed, a bypass configured such that a portion of the working medium discharged from the medium pump 111 flows in and the working medium that has flowed in bypasses the medium pump 111 and returns upstream of the medium pump 111. A flow path may be used to regulate the flow rate into the evaporator 113 . In this case, the inflow amount of the working medium to the evaporator 113 is adjusted by controlling the opening degree of the valve body provided in the bypass flow path.

<Second embodiment>
FIG. 6 is a schematic diagram of the power generator 100A of the second embodiment. The power generator 100A will be described with reference to FIGS. 1 and 6. FIG.

The power generation device 100A differs from the power generation device 100 in that it further includes a temperature detection unit 135 that detects the temperature of the heating medium flowing into the evaporator 113 and in the determination processing of the determination processing unit 134 . Except for these differences, the description of the power generator 100 applies to the power generator 100A.

The temperature detection unit 135 is attached to a pipeline arranged upstream of the evaporator 113 in the flow direction of the heating medium. A temperature sensor capable of detecting the temperature of the heating medium flowing through the pipe line upstream of the evaporator 113 can be used as the temperature detection unit 135 .

The temperature detector 135 is configured to generate a detection signal representing the temperature of the heating medium. The temperature detection unit 135 is wired or wirelessly connected to the determination processing unit 134 so that the detection signal is output from the temperature detection unit 135 to the determination processing unit 134 .

The determination processing unit 134 executes temperature determination processing instead of the upper limit determination processing described above. In the temperature determination process, the determination processing unit 134 compares the temperature of the heating medium indicated by the detection signal from the temperature detection unit 135 with a predetermined temperature threshold, and determines whether the temperature of the heating medium exceeds the temperature threshold. judge.

The determination processing unit 134 executes the degree-of-superheat determination processing after the temperature determination processing. In the degree-of-superheat determination process, the determination processing unit 134 uses different determination criteria depending on the result of the temperature determination process. FIG. 7 is a conceptual graph of criteria used in the degree-of-superheat determination process. The degree-of-superheat determination processing of the determination processing unit 134 will be described with reference to FIGS. 2, 6 and 7. FIG.

The horizontal axis of the graph in FIG. 7 represents the temperature of the heating medium detected by the temperature detection unit 135 . The vertical axis of the graph in FIG. 7 represents the degree of superheat of the working medium flowing through conduit 116 .

In the temperature determination process, when the determination result (step S134: No) is obtained that the temperature of the heating medium is equal to or lower than the temperature threshold, the determination processing unit 134 uses the first control target range to determine the degree of superheat. It is determined whether or not it is within the first control target range. The lower and upper limits of the first control target range are constant regardless of the temperature of the heating medium. The first control target range is similar to the control target range described with reference to FIG. The description regarding the control target range described with reference to FIG. 2 is incorporated into the first control target range.

In the temperature determination process, when it is determined that the temperature of the heating medium exceeds the temperature threshold (step S134: Yes), the determination processing unit 134 sets the second control target range higher than the first control target range. Using the target range, it is determined whether the degree of superheat is within the second control target range. The lower limit of the second target control range is set to a larger value than the lower limit of the first target control range. The upper limit of the second control target range is set to a value greater than the upper limit of the first control target range. The lower and upper limits of the second control target range take larger values as the temperature of the heating medium becomes higher than the temperature threshold. In FIG. 7, when the temperature of the heating medium is at the temperature threshold, the upper limit value of the first control target range matches the upper limit value of the second control target range, and the lower limit value of the first control target range corresponds to the second control target range. Matches the lower limit of the target range. Alternatively, when the temperature of the heating medium is at the temperature threshold, the upper limit of the second control target range may be greater than the upper limit of the first control target range, and the lower limit of the second control target range may be: It may be greater than the lower limit of the first control target range. Although the lower and upper limits of the second control target range increase linearly in FIG. 7, they may increase non-linearly. The difference between the upper limit and the lower limit of the second control target range in FIG. 7 is equal to the difference between the upper limit and the lower limit of the first control target range in FIG. Alternatively, the difference between the upper limit and the lower limit of the second control target range may be larger or smaller than the difference between the upper limit and the lower limit of the first control target range.

Regarding the setting of the temperature threshold and the second control target range, under the degree of superheat determination process using the first control target range, the pressure inside the pipe 116 is set in consideration of the withstand pressure capability of the pipe 116. Consideration is given to the amount of evaporation per unit time of the working medium, which may approach the pressure too closely. That is, the temperature threshold is set to a value that is predicted to cause the amount of evaporation of the working medium per unit time to become too large under the degree-of-superheat determination process using the first control target range. The lower and upper limits of the second control target range are set so that the amount of evaporation of the working medium per unit time does not become too large under the temperature of the heating medium exceeding the temperature threshold.

The operations of the determination processing unit 134 and the inflow control unit 131 will be described below with reference to FIGS. 6 to 8. FIG. FIG. 8 is a schematic flow chart showing exemplary operations of the determination processing unit 134 and the inflow control unit 131. As shown in FIG.

The determination processing unit 134 waits for reception of detection signals from the temperature detection units 133, 135 and the pressure detection unit 132 (step S112), and after receiving these detection signals, calculates the degree of superheat (step S120). After calculating the degree of superheat, temperature determination processing (step S134) is performed.

In the temperature determination process (step S134), the determination processing unit 134 compares the temperature of the heating medium indicated by the detection signal from the temperature detection unit 135 with the temperature threshold. If the determination result (step S134: No) is obtained that the temperature of the heating medium does not exceed the temperature threshold, the determination processing unit 134 uses the first control target range to perform the superheat degree determination process (step S141). Run. If the determination result that the temperature of the heating medium exceeds the temperature threshold is obtained (step S134: Yes), the determination processing unit 134 uses the second control target range to perform the superheat degree determination process (step S142). Run.

In the degree-of-superheat determination processing (steps S141 and S142), one of the following determination results is obtained.
(Determination result 1) Determination result that the calculated degree of superheat (step S120) is below the lower limit of the first control target range or the second control target range (step S141: No, lower, or step S142: No, bottom).
(Determination result 2) Determination result that the calculated degree of superheat (step S120) is within the first control target range or the second control target range (step S141: Yes, or step S142: Yes ).
(Determination result 3) Determination result that the calculated degree of superheat (step S120) exceeds the range of the first control target range or the second control target range (step S141: No, upper, or step S142: No, above).

The obtained determination result is transmitted from the determination processing unit 134 to the inflow control unit 131 . When the determination result 1 described above is output to the inflow control unit 131, the inflow control unit 131 reduces the rotational speed of the medium pump 111 (step S150). In this case, the amount of working medium flowing into the evaporator 113 is reduced, so the degree of superheat of the working medium in the conduit 116 is increased, and is within the control target range. When the determination result 2 described above is output to the inflow control unit 131, the inflow control unit 131 maintains the rotation speed of the medium pump 111 (step S160). In this case, the superheat of the working medium in line 116 remains within the control target range. When the determination result 3 described above is output to the inflow control unit 131, the inflow control unit 131 increases the rotational speed of the medium pump 111 (step S170). In this case, the amount of working medium flowing into the evaporator 113 increases, so the degree of superheat of the working medium in the conduit 116 decreases and falls within the control target range.

In the temperature range higher than the temperature threshold, the upper limit of the second control target range is set to a value larger than the upper limit of the first control target range. When the first control target range is used (step S142), it is less likely to be obtained than when the first control target range is used (step S141). On the other hand, the lower limit of the second target control range is set to a larger value than the lower limit of the first target control range. Therefore, determination result 1 is more likely to be obtained when the second control target range is used (step S142) than when the first control target range is used (step S141). Therefore, when step S142 is executed, control for increasing the rotation speed of the medium pump 111 (step S170) is less likely to be performed, while control for lowering the rotation speed of the medium pump 111 (step S150) is more likely to be performed. It's becoming That is, when step S142 is executed, the supply of the working medium from medium pump 111 to evaporator 113 is suppressed. As a result, evaporation of the working medium in the evaporator 113 and an increase in pressure inside the pipe 116 are also suppressed.

Regarding the above-described embodiment, the determination processing unit 134 performs determination processing using one temperature threshold. However, the determination processing unit 134 may perform determination processing using a plurality of temperature thresholds. The determination processing of the determination processing unit 134 when multiple temperature thresholds are used will be described with reference to FIGS. 6 and 9. FIG. FIG. 9 is a conceptual graph of criteria used in the degree-of-superheat determination process.

The horizontal axis of the graph in FIG. 9 represents the temperature of the heating medium detected by the temperature detection section 135 . The vertical axis of the graph in FIG. 9 represents the degree of superheat of the working medium flowing through conduit 116 .

Symbols “T1” to “T4” shown in FIG. 9 are temperature threshold values used in temperature determination processing (T1<T2<T3<T4). Five control target ranges divided by temperature thresholds T1 to T4 are used in the degree-of-superheat determination process. In the temperature determination process, when the determination result that the temperature of the heating medium is equal to or lower than the temperature threshold value T1 is obtained, the control target range used in the degree of superheat determination process is defined as "first control target range”. In the following description, the control target range used in the degree-of-superheat determination process when the determination result that the temperature of the heating medium is higher than the temperature threshold value T1 and equal to or lower than the temperature threshold value T2 is obtained in the temperature determination process. It is called a "second control target range". In the following description, the control target range used in the degree-of-superheat determination process when the determination result that the temperature of the heating medium is higher than the temperature threshold value T2 and equal to or lower than the temperature threshold value T3 is obtained in the temperature determination process. It is called the "third control target range". In the following description, the control target range used in the degree-of-superheat determination process when the determination result that the temperature of the heating medium is higher than the temperature threshold value T3 and equal to or lower than the temperature threshold value T4 is obtained in the temperature determination process. It is called a "fourth control target range". In the temperature determination process, when the determination result that the temperature of the heating medium exceeds the temperature threshold value T4 is obtained, the control target range used in the degree of superheat determination process is described in the following description as "fifth control called "target range".

The lower and upper limits of each of the first to fifth control target ranges are constant. However, the lower limit and the upper limit are different between the first control target range to the fifth control target range. The lower and upper limits of the second control target range are greater than the lower and upper limits of the first control target range. The lower and upper limits of the third control target range are greater than the lower and upper limits of the second control target range. The lower and upper limits of the fourth control target range are greater than the lower and upper limits of the third control target range. The lower limit and upper limit of the fifth control target range are greater than the lower limit and upper limit of the fourth control target range.

In the degree-of-superheat determination process, one of the first control target range to the fifth control target range is selected based on the temperature of the heating medium (the temperature detected by the temperature detection unit 135). In the degree-of-superheat determination process, when it is determined that the degree of superheat is below the lower limit of the selected control target range, the inflow control unit 131 reduces the rotation speed of the medium pump 111 . In the degree-of-superheat determination process, when it is determined that the degree of superheat exceeds the upper limit of the selected control target range, the inflow control unit 131 increases the rotational speed of the medium pump 111 . Even under the setting of the control target range shown in FIG. 9, as the temperature of the heating medium increases, the inflow amount of the working medium from the medium pump 111 to the evaporator 113 and the increase in the internal pressure of the conduit 116 are suppressed. .

In the above-described embodiment, the temperature detection unit 135 detects the temperature of the heating medium flowing through the pipeline arranged upstream of the evaporator 113 . However, the temperature detection unit 135 may detect the temperature of the heating medium flowing through the pipeline arranged downstream of the evaporator 113 .

The techniques of the above-described embodiments are suitably used in various technical fields where power generation is required.

100, 100A...... power generator 110...... heat recovery part 111..... medium pump 113...... evaporator 114・・・・・・・・・・Expander 115・・・・・・・・Condenser 120・・・・・・・・ Generator 131・・・・・・・・Inflow control unit 134 ..... Judgment processing unit

Claims (6)

The heat of the heating medium supplied to the evaporator is recovered by circulating the working medium sent out by the medium pump through the evaporator, the expander and the condenser in order and then returning to the medium pump. a heat recovery section;
a generator driven by the expander;
an upper limit determination process for determining whether or not the pressure in a pipe connecting the evaporator and the expander exceeds a predetermined upper limit threshold; a determination processing unit that executes a superheat degree determination process for determining whether or not the medium pump is within a range, and a rotation speed determination process for determining whether or not the rotation speed of the medium pump exceeds a predetermined rotation speed threshold; ,
an inflow control unit that controls an inflow amount of the working medium into the evaporator based on the result of determination processing by the determination processing unit;
In the upper limit determination process, when a determination result is obtained that the pipe internal pressure is equal to or less than the upper limit threshold value, the inflow control unit determines that the degree of superheat is the above Control the inflow so that it falls within the control target range,
In the upper limit determination process, when a determination result is obtained that the pipe internal pressure exceeds the upper limit threshold, the inflow control unit reduces the inflow so that the pipe internal pressure is equal to or lower than the upper limit threshold. After reducing, based on the determination result of the superheat degree determination process, controlling the inflow so that the degree of superheat falls within the control target range,
In the upper limit determination process, a determination result is obtained that the pipe internal pressure is equal to or less than the upper threshold, and in the rotational speed determination process, it is determined that the rotational speed of the medium pump is equal to or less than the rotational speed threshold. When the determination result is obtained, the inflow control unit controls the inflow amount based on the determination result of the superheat degree determination process so that the degree of superheat falls within the control target range,
In the rotational speed determination process, when a determination result is obtained that the rotational speed of the medium pump exceeds the rotational speed threshold, the inflow control unit adjusts the rotational speed of the medium pump to the rotational speed A power generating device that reduces said inflow to a value below a number threshold . The determination processing unit further executes a lower limit determination process for determining whether or not the in-pipe pressure is below a predetermined lower limit threshold,
When the pipe internal pressure is within the pressure range defined by the lower limit threshold value and the upper limit threshold value, the inflow control unit determines that the degree of superheat is the control target based on the determination result of the degree-of-superheat determination process. Control the inflow so that it falls within the range,
When the pipe internal pressure is outside the pressure range, the inflow control unit adjusts the inflow so that the pipe internal pressure falls within the pressure range, and then adjusts the determination result of the superheat degree determination process. The power generator according to claim 1, wherein the inflow is controlled such that the degree of superheat falls within the control target range based on. The heat of the heating medium supplied to the evaporator is recovered by circulating the working medium sent out by the medium pump through the evaporator, the expander and the condenser in order and then returning to the medium pump. a heat recovery section;
a generator driven by the expander;
a temperature determination process for determining whether or not the temperature of the heating medium for evaporating the working medium by exchanging heat with the working medium in the evaporator exceeds a predetermined temperature threshold; When it is determined that the temperature of the heating medium exceeds the temperature threshold, the control target range of the degree of superheat of the working medium in the conduit connecting the evaporator and the expander is increased. , a determination processing unit that executes a superheat degree determination process that determines whether the degree of superheat is within the control target range;
an inflow control unit that controls an inflow amount of the working medium into the evaporator based on the result of the superheat degree determination process so that the degree of superheat of the working medium falls within the control target range; There is a power generator. The heat of the heating medium supplied to the evaporator is recovered by circulating the working medium sent out by the medium pump through the evaporator, the expander and the condenser in order and then returning to the medium pump. a heat recovery section;
a generator driven by the expander;
a temperature determination process for determining whether or not the temperature of the heating medium for evaporating the working medium by exchanging heat with the working medium in the evaporator exceeds a predetermined temperature threshold; When a determination result is obtained that the temperature of the heating medium is equal to or lower than the temperature threshold, the degree of superheat of the working medium in the conduit connecting the evaporator and the expander is controlled by the first control of the degree of superheat. A second control target range higher than the first control target range is determined when a determination result is obtained that the temperature of the heating medium exceeds the temperature threshold. A determination processing unit that executes a superheat degree determination process that determines whether the degree of superheat is within the
When the determination result that the temperature of the heating medium is equal to or lower than the temperature threshold value is obtained, based on the result of the superheat degree determination process, so that the degree of superheat falls within the first control target range, The amount of inflow of the working medium into the evaporator is controlled, and when the determination result that the temperature of the heating medium exceeds the temperature threshold is obtained, the degree of superheat is within the second control target range. and an inflow control unit that controls the inflow amount so as to fit in the power generator. Control of a power generator that circulates the working medium sent out by a medium pump through an evaporator, an expander, and a condenser in order and then returns to the medium pump, and drives a generator using the expander. a method,
executing an upper limit determination process for determining whether or not the internal pressure of a pipeline connecting the evaporator and the expander exceeds a predetermined upper threshold;
executing a rotation speed determination process for determining whether or not the rotation speed of the medium pump exceeds a predetermined rotation speed threshold;
executing a superheat degree determination process for determining whether or not the degree of superheat of the working medium in the pipe falls within a predetermined control target range;
In the upper limit determination process, when a determination result is obtained that the pipe internal pressure is equal to or lower than the upper limit threshold value, the above controlling an inflow of the working medium into an evaporator;
In the upper limit determination process, when it is determined that the in-pipe pressure exceeds the upper threshold, the inflow is reduced so that the in-pipe pressure becomes equal to or lower than the upper threshold. controlling the inflow so that the degree of superheat falls within the control target range;
In the upper limit determination process, a determination result is obtained that the pipe internal pressure is equal to or less than the upper threshold, and in the rotational speed determination process, it is determined that the rotational speed of the medium pump is equal to or less than the rotational speed threshold. Controlling the inflow amount so that the degree of superheat falls within the control target range based on the determination result of the degree-of-superheat determination process when the determination result is obtained;
In the rotation speed determination process, when a determination result is obtained that the rotation speed of the medium pump exceeds the rotation speed threshold value, the rotation speed of the medium pump is set to a value equal to or lower than the rotation speed threshold value. and reducing said inflow . A control method of a power plant. Control of a power generator that circulates the working medium sent out by a medium pump through an evaporator, an expander, and a condenser in order and then returns to the medium pump, and drives a generator using the expander. a method,
performing temperature determination processing for determining whether or not the temperature of a heating medium that exchanges heat with the working medium in the evaporator and evaporates the working medium exceeds a predetermined temperature threshold;
In the temperature determination process, when it is determined that the temperature of the heating medium exceeds the temperature threshold, the degree of superheat of the working medium in the conduit connecting the evaporator and the expander and executing a superheat degree determination process for determining whether or not the degree of superheat is within the control target range by increasing the control target range for
controlling the amount of inflow of the working medium into the evaporator so that the degree of superheat of the working medium falls within the control target range based on the result of the degree-of-superheat determination process. control method.

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