JP2016160869A - Low temperature heat recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low temperature heat recovery system capable of miniaturizing a device and stabilizing turbine output without increasing equipment costs.SOLUTION: A low temperature heat recovery system includes a waste heat gas discharged from an engine 2 with a supercharger 1, a first heat exchanger 3 recovering heat from the waste heat gas, a two-phase flow conversion nozzle 4, a generator 6 for introducing two-phase flow jet of a gas phase and a liquid phase produced by the two-phase flow conversion nozzle to a two-phase flow turbine 5, and generating power by rotating the two-phase flow turbine 5, a condenser 7 for cooling an organic medium to liquefy the same, a medium tank 8 for storing the organic medium, and a circulation pump 9 for feeding the organic medium from the medium tank 8 to the first heat exchanger 3. A thermometer 31 is disposed in a transfer pipe 10, a measured temperature is transferred to a control portion 12, and the control portion 12 determines a saturation pressure Pa corresponding to the temperature of the organic medium, and controls a rotating speed of the circulation pump on the basis of the saturation pressure Pa so that the organic medium keeps the liquid phase.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a low-temperature heat recovery system, and more particularly to a low-temperature heat recovery system that recovers heat from a marine motor with a supercharger for ships.

  As a low-temperature heat recovery system, an ORC (Organic Rankine Cycle) power generation system that drives a turbine by vaporizing a low boiling point organic medium is a typical system, and its application to ships has also been reported. As examples of the ORC power generation system, the techniques of Patent Documents 1 and 2 are disclosed.

JP2013-167241A JP 2011-231636 A

  In the technique described in Patent Literature 1, heat is recovered from scavenging of a prime mover to an organic medium in a heat exchanger, the organic medium is vaporized, only the gas is introduced into a steam turbine, and power is generated by a generator. In this method, since the organic medium is vaporized from the heat exchanger to the steam turbine, the pipe size becomes large and the equipment cost increases.

  In Patent Document 2, a method is clarified so that the organic medium introduced into the steam turbine is only gas, and an evaporator is used as a heat exchanger in front of the steam turbine. However, the use of an evaporator increases the size of the device.

  Further, when it is necessary to vaporize the organic medium, the organic medium is not sufficiently vaporized unless the pressure is lowered when the waste heat temperature is low, and the output of the steam turbine is reduced.

  An object of the present invention is to provide a low-temperature heat recovery system capable of downsizing the apparatus and stabilizing turbine output without causing an increase in equipment cost.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

1. A first heat exchanger that recovers heat from the waste heat gas that exchanges heat between the waste heat gas discharged from the motor with a supercharger and the organic medium that is pumped in a liquid phase;
A two-phase flow nozzle for converting the organic medium heat recovered by the first heat exchanger into a two-phase flow of a gas phase and a liquid phase;
A generator for generating electric power by rotating the two-phase flow turbine by introducing a gas-phase and liquid-phase two-phase flow jet generated by the two-phase flow nozzle into the two-phase flow turbine;
A condenser for cooling and liquefying the organic medium discharged from the two-phase turbine;
A medium tank for storing an organic medium liquefied by the condenser;
A circulation pump for sending an organic medium from the medium tank to the first heat exchanger;
A thermometer is provided in the transfer pipe of the organic medium from the first heat exchanger to the two-phase flow nozzle,
The temperature measured by the thermometer is sent to the control unit, and the control unit obtains a saturation pressure Pa corresponding to the temperature of the organic medium. Based on the saturation pressure Pa, the control unit maintains the liquid phase in the organic medium. The low-temperature heat recovery system is characterized in that the number of rotations of the circulation pump is controlled.

2. A second heat exchanger that recovers heat from the pressurized scavenging that exchanges heat between the pressurized scavenging obtained by compression from the supercharger and the organic medium that is pumped in a liquid phase;
A two-phase flow nozzle for converting the organic medium heat-recovered by the second heat exchanger into a two-phase flow of a gas phase and a liquid phase;
A generator for generating electric power by rotating the two-phase flow turbine by introducing a gas-phase and liquid-phase two-phase flow jet generated by the two-phase flow nozzle into the two-phase flow turbine;
A condenser for cooling and liquefying the organic medium discharged from the two-phase turbine;
A medium tank for storing an organic medium liquefied by the condenser;
A circulation pump for feeding an organic medium from the medium tank to the second heat exchanger;
A thermometer is provided in the transfer pipe of the organic medium from the second heat exchanger to the two-phase flow nozzle,
The temperature measured by the thermometer is sent to the control unit, and the control unit obtains a saturation pressure Pa corresponding to the temperature of the organic medium. Based on the saturation pressure Pa, the control unit maintains the liquid phase in the organic medium. The low-temperature heat recovery system is characterized in that the number of rotations of the circulation pump is controlled.

3. A first heat exchanger that recovers heat from the waste heat gas that exchanges heat between the waste heat gas discharged from the motor with a supercharger and the organic medium that is pumped in a liquid phase;
A second heat exchanger that recovers heat from the pressurized scavenging that exchanges heat between the pressurized scavenging obtained by compression from the supercharger and the organic medium that is pumped in a liquid phase;
A two-phase flow nozzle for converting the organic medium heat-recovered by the first heat exchanger and the second heat exchanger into a two-phase flow of a gas phase and a liquid phase;
A generator for generating electric power by rotating the two-phase flow turbine by introducing a gas-phase and liquid-phase two-phase flow jet generated by the two-phase flow nozzle into the two-phase flow turbine;
A condenser for cooling and liquefying the organic medium discharged from the two-phase turbine;
A medium tank for storing an organic medium liquefied by the condenser;
A circulation pump for sending an organic medium from the medium tank to the first heat exchanger and the second heat exchanger;
A thermometer is provided in a transfer pipe for the organic medium from the first heat exchanger and the second heat exchanger to the two-phase flow nozzle,
The temperature measured by the thermometer is sent to the control unit, and the control unit obtains a saturation pressure Pa corresponding to the temperature of the organic medium. Based on the saturation pressure Pa, the control unit maintains the liquid phase in the organic medium. The low-temperature heat recovery system is characterized in that the number of rotations of the circulation pump is controlled.

4). A third heat exchanger in the line for sending the organic medium from the circulation pump;
The motor is provided with a cooling pipe for passing cooling water that absorbs heat generated from the motor,
Providing a cooling water pipe circulating between the cooling pipe and the third heat exchanger;
The said 3rd heat exchanger has the structure which carries out a heat transfer to the said organic medium from the cooling water which absorbed the heat_generation | fever of the said motor | power_engine, and raised the temperature, The said any one of 1-3 characterized by the above-mentioned. Low temperature heat recovery system.

5. The control unit has a storage unit for storing “organic medium temperature-saturation pressure correspondence information” in which the temperature of the organic medium and the saturation pressure at the temperature are associated with each other.
The thermometer transmits a measured temperature obtained by measuring the temperature of the organic medium to the control unit,
Upon receiving the measured temperature, the control unit obtains a saturation pressure based on the “organic medium temperature-saturation pressure correspondence information” stored in the storage unit,
Next, the number of revolutions of the circulating pump is controlled based on the obtained saturation pressure, and the low-temperature heat recovery system according to any one of 1 to 4 above.

6). The control unit further includes a storage unit that stores a predetermined pressure such that the organic medium maintains a liquid phase,
The control unit calculates a set pressure by adding the predetermined pressure to the saturation pressure,
6. The low-temperature heat recovery system according to 5 above, wherein the number of rotations of the circulation pump is controlled based on the set pressure.

  According to the present invention, in heat exchange using an organic medium, the organic medium is not vaporized, so that only the liquid phase is handled as a heat exchanger, and specifications without phase change are possible. Therefore, an evaporator is not required as a heat exchanger as in the prior art, and not only the configuration of the heat exchanger can be simplified, but also the effect of downsizing the equipment can be obtained.

  In addition, according to the present invention, only the liquid phase is provided from the heat exchanger to the two-phase flow nozzle, so that a gas-liquid separator is not required as in the prior art.

  Furthermore, according to the present invention, since the organic medium is transferred in the liquid phase from the heat exchanger to the two-phase flow turbine, the diameter of the pipe from the heat exchanger to the two-phase flow turbine can be reduced, and the cost can be reduced. it can.

Furthermore, according to the present invention, an effect of stabilizing the turbine output can be obtained by not evaporating the organic medium in the heat exchanger. As a result, the waste heat can be effectively recovered even when the temperature is relatively low. Therefore, the waste heat source can be applied to a wide variety of waste heat sources provided in the supercharger-equipped motor.
Furthermore, according to the present invention, since the organic medium is not vaporized in the heat exchanger, the control can be easily realized because only the liquid phase is handled and only the saturation pressure is observed.

Explanatory drawing which shows an example of the low-temperature heat recovery system of this invention Diagram showing an example of a control table Explanatory drawing which shows the other example of the low-temperature heat recovery system of this invention Explanatory drawing which shows the other example of the low-temperature heat recovery system of this invention Explanatory drawing which shows the other example of the low-temperature heat recovery system of this invention Explanatory drawing which shows the other example of the low-temperature heat recovery system of this invention Explanatory drawing which shows the other example of the low-temperature heat recovery system of this invention

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram showing an example of the low-temperature heat recovery system of the present invention.

  The example of illustration has shown an example in the case of heat | fever recovery from the waste heat gas discharged | emitted from the motor | power_engine 2 with the supercharger 1. FIG.

  The low-temperature heat recovery system of the present invention exchanges heat between the waste heat gas discharged from the prime mover 2 with the supercharger 1 and the organic medium pumped in a liquid phase, and heat is generated from the waste heat gas. A first heat exchanger 3 to be recovered is provided, and a two-phase flow nozzle 4 is provided for converting the organic medium heat recovered by the first heat exchanger 3 into a two-phase flow of a gas phase and a liquid phase. The low-temperature heat recovery system of the present invention can be preferably applied to ships.

  The low-temperature heat recovery system of the present invention introduces a gas-phase and liquid-phase two-phase flow jet generated by the two-phase flow nozzle 4 into the two-phase flow turbine 5 and rotates the two-phase flow turbine 5. A generator 6 for generating electric power, a condenser 7 for cooling and liquefying the organic medium discharged from the two-phase flow turbine 5, and a medium tank 8 for storing the organic medium liquefied by the condenser 7, A circulation pump 9 for feeding an organic medium from the medium tank 8 to the first heat exchanger 3 is provided. When the circulation pump 9 is driven, a boost pump 9a may be provided in order to exhibit a boosting assist function, or a boost pump 9a may be provided for the convenience of the capacity of the circulation pump 9.

  The first heat exchanger 3 is a heat exchanger for recovering waste heat. In the process of sending the waste heat gas discharged from the prime mover (engine) 2 with the supercharger 1 to the chimney 20, Heat recovery from hot gas.

  The supercharger 1 includes a turbine 1 a that is rotated by waste heat gas discharged from the prime mover 2 and a compressor 1 b that compresses scavenging gas supplied to the prime mover 2.

  As the organic medium, for example, an organic medium having a low boiling point such as R245fa and R134a which are alternative chlorofluorocarbons can be preferably used as a heat exchange medium with a medium / low temperature heat source.

  The organic medium exiting the first heat exchanger 3 is supplied to a turbine unit (not shown) while remaining in a liquid phase. The turbine unit includes at least a two-phase flow nozzle 4 and a two-phase flow turbine 5.

  The two-phase flow nozzle 4 is partially vaporized and generates a two-phase flow in which a gas phase and a liquid phase are mixed. Then, the two-phase flow is discharged from the tip of the two-phase flow nozzle 4 at a high speed.

  At this time, in the two-phase flow nozzle 4, the shearing stress of the gas divides the liquid phase into fine droplets toward the nozzle tip, and the momentum of the gas is transmitted to the droplets.

  The microfluidization can be sufficiently accelerated by the dense coupling of the gas phase and the liquid phase, and the gas flow rate and the droplet flow rate can be made uniform at the tip outlet of the two-phase flow nozzle 4. It is desirable that the flow rate of the two-phase flow from the nozzle be sufficiently lower than the erosion limit speed.

  In order to effectively convert the thermal energy of the organic medium into kinetic energy, it is desirable to make the droplets as uniform and fine as possible.

  The tip of the two-phase flow nozzle 4 is arranged in a predetermined direction toward the turbine blades of the two-phase flow turbine 5.

  For example, when the generator 6 uses a three-phase induction generator, when the rated rotational speed (3600 rpm) is reached, a generator breaker (not shown) is closed and power generation is started.

  In the generator 6, a two-phase flow of a gas phase and a liquid phase generated by the two-phase flow nozzle 4 is introduced into the two-phase flow turbine 5, and the two-phase flow turbine 5 is rotated to generate electric power.

  In the present invention, the low-temperature waste heat of the waste heat gas discharged from the prime mover 2 with the supercharger 1 can be recovered to generate power.

  In the present invention, as a motor with a supercharger, for example, a diesel engine or a gas engine provided with a supercharger can be preferably exemplified.

  In the condenser 7, the organic medium discharged from the two-phase flow turbine 5 is cooled and liquefied.

  The organic medium liquefied by the condenser 7 is stored in the medium tank 8. The liquefied organic medium in the medium tank 8 is transferred to the first heat exchanger 3 by the circulation pump 9 and is circulated for use.

  The rotation speed of the circulation pump 9 is controlled by a VFD (Variable Frequency Driver) so as to maintain a heat medium pressure at which evaporation does not occur in the first heat exchanger 3 in accordance with the engine load. At the time of start-up, since the temperature of the organic medium is low, the rotation speed of the circulation pump 9 may be zero, and the circulation of the organic medium may be performed by a boost pump 9a (not shown).

  As described above, by not evaporating the organic medium in the first heat exchanger 3, only the liquid phase is handled as the first heat exchanger 3, and specifications without phase change are possible. Therefore, an evaporator or a vaporizer is not required as the first heat exchanger 3 as in the prior art, and not only the configuration of the heat exchanger can be simplified, but also the effect of downsizing the equipment can be obtained.

  Furthermore, since partial vaporization of the organic medium is performed in a two-phase flow nozzle 4 built in a turbine unit (not shown), only the liquid phase is from the first heat exchanger 3 to the two-phase flow nozzle 4. There is no need for a gas-liquid separator as in the prior art, and in this respect, the effect of reducing the size of the equipment can be obtained.

  Moreover, since the organic medium is transferred from the first heat exchanger 3 to the two-phase flow nozzle 4 in a liquid phase, the diameter of the pipe from the first heat exchanger 3 to the two-phase flow nozzle 4 can be reduced, Cost reduction can be realized.

  Specifically, as shown in the embodiment, the diameter of the pipe from the first heat exchanger 3 to the two-phase flow nozzle 4 is set to 2 with respect to the case where the gas phase is transferred in the conventional manner. The size can be reduced. This also contributes to downsizing of the equipment.

  Especially in a limited space in a ship, downsizing of the equipment is an excellent effect.

  Conventionally, when the waste heat temperature is low, the organic medium is not sufficiently vaporized unless the pressure is reduced in the first heat exchanger, and the turbine output is reduced. By not vaporizing the organic medium in the heat exchanger 3 of 1, the effect of stabilizing the turbine output can be obtained. As a result, the waste heat can be effectively recovered even when the temperature is relatively low. Therefore, the waste heat source can be applied to a wide variety of waste heat sources provided in the supercharger-equipped motor.

  Furthermore, by driving the two-phase flow turbine 5 with a two-phase flow jet, an effect of preventing erosion of the turbine blade can be obtained.

  The first control in the present invention is a control for transferring the organic medium from the first heat exchanger 3 to the two-phase flow turbine 5 in a liquid phase.

  A thermometer 31 is provided in the organic medium transfer pipe 10 from the first heat exchanger to the two-phase flow nozzle 4, and the thermometer 31 measures the temperature of the organic medium and sends the measured temperature to the control unit 12. The control unit 12 obtains a saturation pressure Pa corresponding to the temperature of the organic medium, and based on the saturation pressure Pa, the control unit 12 rotates the circulation pump 9 so that the organic medium maintains a liquid phase. Control the number.

An example of specific control will be described below based on FIG.
The control unit 12 preferably includes a storage unit 120 that stores a table I that associates the temperature of the organic medium with the saturation pressure at the temperature.

  Using the table I, control is performed as follows. That is, the control unit 12 measures the temperature of the organic medium with the thermometer 31 and receives the measured temperature from the thermometer 31. Here, it is preferable that the measured temperature from the thermometer 31 is always transmitted to the control unit, and the control unit 12 can constantly monitor the temperature of the organic medium.

  Next, the control unit 12 calls a saturation pressure corresponding to the received measured temperature based on the table I.

  Next, a set pressure obtained by adding a predetermined pressure to the called saturation pressure is calculated. Here, the predetermined pressure refers to a pressure that takes into account the pressure loss of the piping, the pressure loss in the first heat exchanger, and the like.

  Next, in order to perform PID control, a pump rotation number for maintaining a liquid phase based on the calculated set pressure is calculated.

  Next, a VFD described later is applied by PID control to adjust the pump rotational speed of the circulation pump 9 to match the calculated pump rotational speed so as to maintain the calculated set pressure.

  The rotation speed of the circulation pump 9 is controlled based on the rotation speed calculated based on the set pressure. Therefore, the discharge pressure of the circulation pump 9 is not substantially different from the set pressure calculated by adding a predetermined pressure such as pressure loss to the saturation pressure.

  In addition, the pressure gauge 32 can measure the pressure of the transfer pipe 10 from the first heat exchanger 3 to the two-phase flow nozzle 4.

  In the above example, an example of control using a table has been described, but without using Table I that associates the temperature of the organic medium and the saturation pressure at the temperature, an approximate expression of the temperature and saturation pressure of the organic medium. And the saturation pressure can be calculated based on the temperature.

  Further, the rotation speed of the pump can be obtained based on the calculated set pressure using the table II in which the set pressure is associated with the rotation speed of the circulation pump without using the PID control. Thereby, the pump rotation speed of the circulation pump 9 can also be controlled based on the calculated set pressure.

  Note that the pressure of the organic medium can be controlled by using the adjustment of the opening degree of the valve together with the pump rotation speed.

  At the time of start-up, the turbine shut-off valve 33 is closed and the bypass adjusting valve 35 is in the open state. Subsequently to the boost pump 9a, the circulation pump 9 is automatically started, and the organic medium is passed through the bypass line 11 so that the turbine bypass Start driving.

  The temperature at which the waste heat gas discharged from the prime mover 2 passes through the first heat exchanger 3 rises according to the load on the prime mover 2, and the temperature of the organic medium rises accordingly.

  In the performance test, the temperature of the organic medium reaches about 80 ° C. with a motor load of 60%, and the rotational speed of the circulation pump 9 gradually increases in order to maintain a predetermined organic medium flow rate and pressure.

  In the present invention, the second control is such that the temperature of the outlet of the first heat exchanger is maintained while maintaining the organic medium in a liquid phase between the first heat exchanger and the gas-liquid two-phase flow nozzle. When the temperature is equal to or higher than the predetermined temperature, the organic medium supply to the turbine is controlled.

  At the start of operation, the turbine shut-off valve 33 and the turbine control valve 34 provided in the transfer pipe 10 for the organic medium from the first heat exchanger 3 to the two-phase flow nozzle 4 are closed, and the bypass line 11 The bypass control valve 35 provided in is in an open state.

  When the control unit 12 receives the temperature sent from the thermometer 31 and determines that the temperature has reached a predetermined temperature, the turbine cutoff valve 33 and the turbine control valve 34 are opened, and the bypass control valve 35 is closed. As a result, the transfer line 10 is switched from the bypass line 11 to the two-phase flow nozzle 4 from the first heat exchanger 3.

  When the switching is performed and the two-phase turbine 5 is driven, and the generator 6 is driven, power generation is performed. When the generator 6 connected to the two-phase flow turbine 5 uses a three-phase induction generator, for example, when the rated rotational speed (3600 rpm) is reached, a generator breaker (not shown) is closed and power generation is started.

  In the test operation of the low-temperature waste heat recovery system, after the engine load reached 100%, power generation of about 8% of the waste heat amount was confirmed.

  In the normal stop of the two-phase flow turbine 5, the switching from the turbine control valve 34 to the bypass control valve 35 is gradually performed, and the low-temperature heat recovery system shifts to the operation mode from the transfer pipe 10 to the bypass line 11. When the power generation output becomes zero, the generator circuit breaker is opened and at the same time the turbine shut-off valve 33 is closed.

  The low-temperature heat recovery system of the present invention is a VPC (Variable Phase Cycle) power generation system, and the VPC can always be stopped regardless of the operating state of the prime mover 1. In addition, a cooling seawater pump (not shown) cannot be stopped regardless of the stop of the VPC when used in combination with the hull side, but can be stopped after the stop of the VPC when dedicated to the VPC.

  FIG. 3 is a diagram showing another example of the low-temperature heat recovery system of the present invention. In the figure, the description given with reference to FIG. 1 can be used for the configuration indicated by the same reference numerals as in FIG.

  The illustrated example shows an example in the case where heat recovery is performed from the pressurized scavenge compressed by the compressor 1 b provided in the supercharger 1.

  In another preferred embodiment of the present invention, the marine low-temperature heat recovery system is provided between a pressurized scavenge compressed by a compressor 1b provided in the supercharger 1 and an organic medium pumped in a liquid phase. And a second heat exchanger 13 that performs heat exchange and recovers heat from the pressurized scavenging.

  The second heat exchanger 13 is a heat exchanger that recovers surplus heat from the pressurized scavenge compressed by the compressor 1 b provided in the supercharger 1 using an organic medium, and the compressor 1 b of the supercharger 1. The pressurized scavenging air that is compressed in step S3 and supplied to the prime mover 2 is cooled by an organic medium and recovered. In addition, 40 can use a boiler.

  FIG. 4 is a diagram showing another example of the low-temperature heat recovery system of the present invention. In the figure, for the configuration indicated by the same reference numerals as in FIGS. 1 and 3, the description with reference to FIGS. 1 and 3 can be used.

  In the illustrated example, heat is recovered from the pressurized scavenge compressed by the compressor 1b provided in the supercharger 1, and heat is recovered from the waste heat gas discharged from the motor 2 with the supercharger 1. Is shown.

  FIG. 5 is a diagram showing another example of the low-temperature heat recovery system of the present invention. In the figure, the description given with reference to FIG. 1 can be used for the configuration indicated by the same reference numerals as in FIG.

  The illustrated example shows an example in which waste heat is recovered from the cooling water that cools the prime mover 2 with the supercharger 1, and heat is recovered from the waste heat gas discharged from the prime mover 2 with the supercharger 1.

  A cooling pipe 16 is provided around the prime mover 2, and waste heat from the prime mover 2 is recovered into cooling water in the cooling pipe 16.

  A cooling water pipe 15 through which the cooling water flows is provided between the cooling pipe 16 and the third heat exchanger 14, and the cooling water in the cooling pipe 16 is configured to flow therethrough.

  The third heat exchanger 14 recovers waste heat from the cooling water to an organic medium.

  The cooling water recovered and cooled by the third heat exchanger 14 is preferably introduced again into the cooling pipe 16 so as to contribute to cooling the prime mover 2.

  FIG. 6 is a diagram showing another example of the low-temperature heat recovery system of the present invention. In the figure, the description given with reference to FIGS. 1, 3 and 5 can be applied to the configuration indicated by the same reference numerals as those in FIGS.

  In the illustrated example, waste heat is recovered from the cooling water that cools the prime mover 2 with the supercharger 1, and excess heat is recovered from the pressurized scavenge compressed by the compressor 1 b provided in the supercharger 1. An example is shown.

  FIG. 7 is a diagram showing another example of the low-temperature heat recovery system of the present invention. In the figure, the description given with reference to FIGS. 1, 3 and 5 can be applied to the configuration indicated by the same reference numerals as those in FIGS.

  In the illustrated example, waste heat is recovered from the cooling water that cools the prime mover 2 with the supercharger 1, excess heat is recovered from the pressurized scavenge compressed by the compressor 1 b provided in the supercharger 1, and An example in the case of recovering heat from waste heat gas discharged from the motor 2 with the supercharger 1 is shown.

  In the present invention, in the event of an emergency such as a load interruption of the generator 6, in principle, the turbine cutoff valve 33 blocks the flow path of the transfer pipe 10 to the two-phase flow turbine 5 to prevent the organic medium from flowing in. ing.

  The effects of the present invention will be illustrated below by examples of the present invention.

Experiment 1
When the state of the organic medium in the transfer pipe 10 at the first heat exchanger outlet is 100% liquid phase, the organic medium pressure (MPaA), temperature (° C.) in the transfer pipe 10 at the heat exchanger outlet, Table 1 shows the density (kg / m ³ ), flow rate (kg / h), flow rate (m / s), and diameter (A). In addition, MPaA has shown the absolute pressure.

Comparative experiment 1
When the state of the organic medium in the transfer pipe 10 at the first heat exchanger outlet is 100% gas phase, the organic medium pressure (MPaA), temperature (° C.) in the transfer pipe 10 at the heat exchanger outlet, Table 1 shows the density (kg / m ³ ), flow rate (kg / h), flow rate (m / s), and diameter (A).

  According to Table 1, when the 100% liquid phase is maintained in the heat exchanger outlet pipe, the pipe size is reduced by two sizes from 150A (6 inches) to 100A (4 inches) compared to 100% vaporization. It turns out to be economical.

  Therefore, according to the present invention, in both the first heat exchanger 3 and the second heat exchanger 13, the organic medium remains in a liquid phase (in a liquid state) and functions as a heat exchange medium.

  In addition, although this invention demonstrated that the predetermined pressure in FIG. 1 said the pressure which considered the pressure loss of piping, the pressure loss in a 1st heat exchanger, etc., in FIG. The pressure includes the pressure in consideration of the pressure loss in the second heat exchanger 13 and the third heat exchanger 14.

  Accordingly, in any of the embodiments of FIGS. 1 to 7, the present invention allows simple control because the organic medium functions as a heat exchange medium in the liquid phase only by the temperature of the organic medium. .

1: Supercharger 1a: Turbine 1b: Compressor 2: Primer 3: First heat exchanger 4: Two-phase flow nozzle 5: Two-phase flow turbine 6: Generator 7: Condenser 8: Medium tank 9: Circulation Pump 9a: Boost pump 10: Transfer piping 11: Bypass line 12: Control unit 120: Storage unit 13: Second heat exchanger 14: Third heat exchanger 15: Cooling water piping 16: Cooling piping 20: Chimney 31 : Thermometer 32: Pressure gauge 33: Turbine shutoff valve 34: Turbine control valve 35: Bypass control valve 40: Boiler

Claims (6)

A first heat exchanger that recovers heat from the waste heat gas that exchanges heat between the waste heat gas discharged from the motor with a supercharger and the organic medium that is pumped in a liquid phase;
A two-phase flow nozzle for converting the organic medium heat recovered by the first heat exchanger into a two-phase flow of a gas phase and a liquid phase;
A generator for generating electric power by rotating the two-phase flow turbine by introducing a gas-phase and liquid-phase two-phase flow jet generated by the two-phase flow nozzle into the two-phase flow turbine;
A condenser for cooling and liquefying the organic medium discharged from the two-phase turbine;
A medium tank for storing an organic medium liquefied by the condenser;
A circulation pump for sending an organic medium from the medium tank to the first heat exchanger;
A thermometer is provided in the transfer pipe of the organic medium from the first heat exchanger to the two-phase flow nozzle,
The temperature measured by the thermometer is sent to the control unit, and the control unit obtains a saturation pressure Pa corresponding to the temperature of the organic medium. Based on the saturation pressure Pa, the control unit maintains the liquid phase in the organic medium. The low-temperature heat recovery system is characterized in that the number of rotations of the circulation pump is controlled. A second heat exchanger that recovers heat from the pressurized scavenging that exchanges heat between the pressurized scavenging obtained by compression from the supercharger and the organic medium that is pumped in a liquid phase;
A two-phase flow nozzle for converting the organic medium heat-recovered by the second heat exchanger into a two-phase flow of a gas phase and a liquid phase;
A generator for generating electric power by rotating the two-phase flow turbine by introducing a gas-phase and liquid-phase two-phase flow jet generated by the two-phase flow nozzle into the two-phase flow turbine;
A condenser for cooling and liquefying the organic medium discharged from the two-phase turbine;
A medium tank for storing an organic medium liquefied by the condenser;
A circulation pump for feeding an organic medium from the medium tank to the second heat exchanger;
A thermometer is provided in the transfer pipe of the organic medium from the second heat exchanger to the two-phase flow nozzle,
The temperature measured by the thermometer is sent to the control unit, and the control unit obtains a saturation pressure Pa corresponding to the temperature of the organic medium. Based on the saturation pressure Pa, the control unit maintains the liquid phase in the organic medium. The low-temperature heat recovery system is characterized in that the number of rotations of the circulation pump is controlled. A first heat exchanger that recovers heat from the waste heat gas that exchanges heat between the waste heat gas discharged from the motor with a supercharger and the organic medium that is pumped in a liquid phase;
A second heat exchanger that recovers heat from the pressurized scavenging that exchanges heat between the pressurized scavenging obtained by compression from the supercharger and the organic medium that is pumped in a liquid phase;
A two-phase flow nozzle for converting the organic medium heat-recovered by the first heat exchanger and the second heat exchanger into a two-phase flow of a gas phase and a liquid phase;
A generator for generating electric power by rotating the two-phase flow turbine by introducing a gas-phase and liquid-phase two-phase flow jet generated by the two-phase flow nozzle into the two-phase flow turbine;
A condenser for cooling and liquefying the organic medium discharged from the two-phase turbine;
A medium tank for storing an organic medium liquefied by the condenser;
A circulation pump for sending an organic medium from the medium tank to the first heat exchanger and the second heat exchanger;
A thermometer is provided in a transfer pipe for the organic medium from the first heat exchanger and the second heat exchanger to the two-phase flow nozzle,
The temperature measured by the thermometer is sent to the control unit, and the control unit obtains a saturation pressure Pa corresponding to the temperature of the organic medium. Based on the saturation pressure Pa, the control unit maintains the liquid phase in the organic medium. The low-temperature heat recovery system is characterized in that the number of rotations of the circulation pump is controlled. A third heat exchanger in the line for sending the organic medium from the circulation pump;
The motor is provided with a cooling pipe for passing cooling water that absorbs heat generated from the motor,
Providing a cooling water pipe through which cooling water flows between the cooling pipe and the third heat exchanger;
The said 3rd heat exchanger has a structure which carries out heat transfer to the said organic medium from the cooling water which absorbed the heat_generation | fever of the said motor | power_engine, and rose in temperature. Low temperature heat recovery system. The control unit has a storage unit for storing “organic medium temperature-saturation pressure correspondence information” in which the temperature of the organic medium and the saturation pressure at the temperature are associated with each other.
The thermometer transmits a measured temperature obtained by measuring the temperature of the organic medium to the control unit,
Upon receiving the measured temperature, the control unit obtains a saturation pressure based on the “organic medium temperature-saturation pressure correspondence information” stored in the storage unit,
5. The low-temperature heat recovery system according to claim 1, wherein the number of revolutions of the circulation pump is controlled based on the obtained saturation pressure. The control unit further includes a storage unit that stores a predetermined pressure such that the organic medium maintains a liquid phase,
The control unit calculates a set pressure by adding a predetermined pressure based on the predetermined pressure information to the saturation pressure,
6. The low-temperature heat recovery system according to claim 5, wherein the number of rotations of the circulation pump is controlled based on the set pressure.

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