JP5527513B2 - Fluid machine drive system - Google Patents

Description

  The present invention relates to a fluid machine drive system for driving a fluid machine such as a compressor or a blower using exhaust heat.

  Conventionally, as disclosed in Patent Document 1 below, facilities that generate power using exhaust heat are known. The outline will be described based on FIG. 3 of this document. The exhaust heat power generation facility includes a working medium circulation path 16, a jacket cooling water circulation path 35, an exhaust warm water circulation system 39, and a cooling water circulation system 45.

  Each circuit will be described in turn. The working medium circulation path 16 is a circuit including the steam generator 11, the turbine 12, the condenser 14, and the feed pump 15. The jacket cooling water circulation path 35 is a circuit including a diesel engine 33, a heat recovery heat exchanger 36, a three-way valve 37, a jacket cooling water circulation pump 38, and a heat dissipation heat exchanger 49. The exhaust hot water circulation system 39 is a circuit including the heat recovery heat exchanger 36, a forward water header 41, a hot water circulation pump 40, the steam generator 11, and a return water header 42. Furthermore, the cooling water circulation system 45 is a circuit that sends the water from the cooling tower 48 to the condenser 14 in addition to sending it to the diesel engine 33 and the heat dissipation heat exchanger 49 using the cooling water pump 46.

  Because of such a configuration, the heat of the jacket cooling water of the diesel engine 33 evaporates the working medium in the steam generator 11 via the jacket cooling water circulation path 35 and the exhaust warm water circulation system 39. The generator 12 is driven by the turbine 12 by rotating the turbine 12 with the working medium vapor.

JP 2007-2688 A

  However, in the invention described in Patent Document 1, since the generator is driven by the turbine and the electricity from the generator is sent to the system, the equipment cost increases in relation to legal regulations. In addition, an expensive converter or inverter is required to send electricity from the generator to the system.

  Furthermore, in the invention described in Patent Document 1, the recovered heat is only jacket cooling water. Therefore, it is preferable that other heat, for example, heat discarded when cooling the compressed air from the supercharger to the engine or heat discarded by the exhaust gas from the engine can be recovered. However, even if these are collected, they must be collected efficiently with a simple configuration, and a design that takes into consideration the respective temperatures is particularly required.

  The problem to be solved by the present invention is to provide a system that efficiently recovers various exhaust heat at low cost and drives a fluid machine such as a compressor or a blower.

The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 uses an evaporator that heats and vaporizes a working medium using exhaust heat, and a working medium from the evaporator. An expander that generates power, a condenser that cools and condenses the working medium from the expander, a circulation pump that sends the working medium from the condenser to the evaporator, and a compressor, a blower, or a pump. A fluid machine driven by the expander , and an exhaust gas boiler through which exhaust gas from the engine is passed and generates steam using the exhaust gas heat, compressed air from the supercharger to the engine, and the working medium, The second heat exchanger and the third heat exchanger of the steam from the exhaust gas boiler and the working medium from the second heat exchanger are sequentially used as the evaporator to heat the working medium. Flow A mechanical drive system.

According to the first aspect of the present invention, since the compressor, blower or pump is directly driven by the expander, a generator is not required and it is not necessary to connect to an electric system. Thereby, cost reduction can be aimed at rather than the case where a generator is used. Further, the efficiency is higher than when a compressor or the like is once driven instead of electricity.
According to the first aspect of the present invention, heat can be recovered from the compressed air from the supercharger to the engine and the exhaust gas from the engine to drive the compressor and the like. In addition, the heat recovery rate can be improved by using compressed air from the supercharger to the engine and exhaust gas from the engine in this order.
By the way, the working medium in the circuit including the evaporator, the expander, the condenser, and the circulation pump has an upper limit on the practical temperature in relation to the critical temperature. Therefore, since the exhaust gas from the engine is too hot as it is, it may not be able to directly exchange heat with the working medium in the evaporator. In the case of an engine using a fuel containing sulfur, it is necessary to consider the acid dew point of the exhaust gas. That is, if the exhaust gas and the working medium are directly heat-exchanged in the evaporator and the exhaust gas temperature is lowered too much, the heat exchanger may be corroded. However, according to the first aspect of the present invention, steam is generated by the exhaust gas heat using the exhaust gas boiler, and the steam and the working medium are heat-exchanged, so that such inconvenience can be prevented.

The invention according to claim 2 further includes a first heat exchanger of the engine jacket coolant and a working medium to the second heat exchanger as the evaporator. A fluid machine drive system as described.

According to the invention described in claim 2, it can be jacket coolant of the engine, the compressed air from the supercharger to the engine, and to flue gas or et heat recovery from the engine to drive the like compressor . Moreover, the jacket coolant engine, the compressed air from the supercharger to the engine, and by using the order of the exhaust gas from the engine, it is possible to improve the heat recovery rate.

Further, the invention according to claim 3 is that the engine is a diesel engine mounted on a ship, the fluid machine is an air compressor, and the condenser exchanges heat between the working medium and seawater. The fluid machine drive system according to claim 1 or 2 , wherein the fluid machine drive system is a container.

According to invention of Claim 3 , an air compressor can be driven using the exhaust heat of the engine of a ship. Moreover, since the condenser condenses the working medium using seawater, it is efficient with a simple configuration.

  According to the fluid machine drive system of the present invention, it is possible to provide a system that efficiently collects various exhaust heat at low cost and drives a fluid machine such as a compressor or a blower.

It is the schematic which shows an example of the motive power system with which one Example of the fluid machine drive system of this invention is applied. It is the schematic which shows one Example of the fluid machine drive system of this invention applied to the power system of FIG.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of a power system 1 to which an embodiment of a fluid machine drive system of the present invention is applied. FIG. 2 is a schematic view showing an embodiment of the fluid machine drive system 2 of the present invention applied to the power system 1 of FIG.

  First, the power system 1 will be described with reference to FIG. The power system 1 is a system that generates power using the engine 3. The type of the engine 3 is not particularly limited, but is typically a diesel engine. The power system 1 in the illustrated example is a power system mounted on a ship, and includes a marine diesel engine.

  In the illustrated engine 3, a cylinder 5 is held in a main machine box 4, and a piston 6 is fitted in the cylinder 5 so as to be able to advance and retreat. As is well known, in the case of a diesel engine, the engine 3 sucks air into the cylinder 5 and compresses it with the piston 6 so as to have a high temperature. The fuel is injected and ignited, and the explosion force is transmitted to the crankshaft 9 through the connecting rod 8. The rotational power obtained in this way is used for navigation of ships.

  The lubricating oil in the main engine box 4 is circulated between the oil cooler 10 and maintained at a desired temperature. Specifically, the lubricating oil in the main machine box 4 is supplied to the oil cooler 10 via the oil pump 11 and is cooled by heat exchange with the coolant (for example, seawater) in the oil cooler 10. Returned into box 4. The lubricating oil from the oil cooler 10 is also supplied to the cylinder 5, and after the cylinder 5 is lubricated and cooled, it is returned to the main engine box 4.

  The cylinder 5 is also cooled by a jacket coolant (typically water). Specifically, the water in the jacket 12 of the cylinder 5 is maintained at a desired temperature by being circulated with the first heat exchanger 13. That is, the coolant in the jacket 12 is drawn into the first heat exchanger 13 by the liquid feed pump 14, and exchanges heat with the working medium (or a coolant such as seawater) in the first heat exchanger 13 as will be described later. After being cooled, it is returned to the jacket 12. In FIG. 1, the liquid feed pump 14 is installed in the drainage path from the first heat exchanger 13, but as shown in FIG. 2, it is installed in the liquid supply path to the first heat exchanger 13. May be.

  In the illustrated example, the exhaust gas from the engine 3 is released to the outside air via the exhaust gas supercharger 15 and the exhaust gas boiler 16. In the exhaust gas supercharger 15, as is well known, the air compressor 17 is driven using the energy of the exhaust gas. The compressed air from the air compressor 17 is supplied to the engine 3 (more specifically, in the cylinder 5) via the second heat exchanger 18 as an air cooler. At that time, the compressed air from the air compressor 17 is cooled by exchanging heat with a working medium (or a cooling liquid such as seawater) in the second heat exchanger 18 as will be described later, and then to the engine 3. Supplied.

  As is well known, the exhaust gas boiler 16 is a device that generates heat by exchanging heat between exhaust gas and water. That is, in the exhaust gas boiler 16, the exhaust gas is cooled by water, while the water is vaporized by exhaust gas heat. This steam is heat-exchanged with a working medium (or a coolant such as seawater) in the third heat exchanger 19 as will be described later.

  Next, an embodiment of the fluid machine drive system 2 of the present invention will be described with reference to FIG. The fluid machine drive system 2 of the present embodiment includes an evaporator 20 that heats and vaporizes a working medium using exhaust heat, an expander 21 that generates power using the working medium from the evaporator 20, and the expander A Rankine cycle is configured by sequentially connecting a condenser 22 that cools and condenses the working medium from 21 and a circulation pump 23 that sends the working medium from the condenser 22 to the evaporator 20.

  As the evaporator 20, any one or more of the first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19 described above are provided. That is, the heat exchanger 13 as the evaporator 20 using heat from any one or more of the jacket coolant of the engine 3, the compressed air from the supercharger 15 to the engine 3, and the exhaust gas from the engine 3. , 18 and 19 can heat and vaporize the working medium.

  In this embodiment, all of the first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19 are provided in this order. However, any one of the first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19 may be used as the evaporator 20, or any two may be used as the evaporator 20. May be. Of the first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19, the heat exchanger that is not used as the evaporator 20 is removed from the cycle of FIG. Instead, it is a heat exchanger with a coolant (for example, seawater).

  When a plurality of heat exchangers are used as the evaporator 20 among the first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19, the installation order is the heat of the downstream (expansion machine 21 side). The first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19 are preferably installed in series so that the working medium exchanges heat with the hot fluid as the exchanger.

  For example, when the first heat exchanger 13 and the third heat exchanger 19 are used, the working medium from the circulation pump 23 is passed through the first heat exchanger 13 and then to the third heat exchanger 19. . In this case, as described above, the second heat exchanger 18 that is not used as the evaporator 20 is a heat exchanger between compressed air and seawater. For example, when the second heat exchanger 18 and the third heat exchanger 19 are used, the working medium from the circulation pump 23 passes through the second heat exchanger 18 and then passes through the third heat exchanger 19. Is done. In this case, as described above, the first heat exchanger 13 that is not used as the evaporator 20 is a heat exchanger for jacket cooling liquid and seawater.

  In any case, the working medium supplied to the evaporator 20 in the circulation pump 23 is heated and evaporated in the evaporator 20. When a plurality of heat exchangers among the first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19 are used as the evaporator 20, the working medium does not change phase in the upstream heat exchanger. Heated and the working medium is vaporized in the downstream heat exchanger. Alternatively, the working medium may be vaporized by a heat exchanger upstream from the most downstream heat exchanger, and the working medium may be further heated by a heat exchanger downstream from it. Therefore, the evaporator 20 may function as a preheater or a superheater in addition to functioning as a literal evaporator.

  In order to heat and vaporize the working medium in the evaporator 20 as desired, each heat exchanger constituting the evaporator 20 exchanges heat with the working medium based on the temperature or pressure of the working medium on the outlet side of the heat exchanger. The flow rate of the fluid to be used (jacket coolant in the first heat exchanger 13, compressed air in the second heat exchanger 18, and steam from the exhaust gas boiler 16 in the third heat exchanger 19) may be controlled. At this time, at the outlets of the heat exchangers 13, 18, and 19, if the working medium is liquid, it is preferable to control based on temperature, and if the working medium is gas, it is preferable to control based on pressure.

  For example, when the first heat exchanger 13, the second heat exchanger 18, and the third heat exchanger 19 are installed in series in this order and the working medium is phase-changed from liquid to gas in the third heat exchanger 19 Control may be performed as follows. That is, in the first heat exchanger 13, the working medium and the jacket coolant are heat-exchanged, and the jacket cooling to the first heat exchanger 13 is performed based on the temperature of the working medium at the outlet of the first heat exchanger 13. The supply flow rate of the liquid may be adjusted. Further, in the second heat exchanger 18, the working medium and the compressed air are heat-exchanged, and based on the temperature of the working medium at the outlet of the second heat exchanger 18, the compressed air is supplied to the second heat exchanger 18. The supply flow rate may be adjusted. Furthermore, in the third heat exchanger 19, the working medium and steam exchange heat, and the amount of steam flowing into the third heat exchanger 19 based on the pressure of the working medium at the outlet of the third heat exchanger 19. Can be adjusted.

  The supply flow rate of the fluid that exchanges heat with the working medium to each of the heat exchangers 13, 18, and 19 can be controlled by controlling a flow rate adjusting mechanism 24 such as a pump or a valve provided in the fluid conduit. The temperature or pressure of the working medium at the outlet of each heat exchanger 13, 18, 19 is detected by a temperature sensor or a pressure sensor. In the above example, the temperature sensor 25 is provided at the outlet of the first heat exchanger 13, the temperature sensor 26 is provided at the outlet of the second heat exchanger 18, and the pressure sensor 27 is provided at the outlet of the third heat exchanger 19.

  The type of the expander 21 is not particularly limited. For example, the expander 21 is a scroll type, a screw type, or a turbine type, and generates power using the working medium from the evaporator 20 to drive various fluid machines. At that time, the fluid machine 28 is driven by the expander 21 without using a generator. The fluid machine 28 is not particularly limited in type, and is, for example, a compressor, a blower (fan or blower), or a pump.

  In the illustrated example, the air compressor is driven by the expander 21, and the compressed air is discharged as, for example, microbubbles on the bottom of the ship, and is used to reduce frictional resistance with seawater by forming a bubble film on the bottom of the ship. In this case, the microbubbles are necessary during the navigation of the ship (that is, during the operation of the engine 3), but the fluid machine drive system 2 can be operated during the engine operation to generate compressed air. Therefore, the time required for compressed air matches the time zone in which compressed air can be generated, and the demand and supply of compressed air can be matched.

  However, in the fluid machine drive system 2 of the present invention, the fluid machine 28 driven by the expander 21 is not limited to an air compressor for use in such applications, but is used in addition to an air compressor used for other applications. The present invention can be similarly applied to a compressor other than the compressor, and a blower and a pump other than the compressor.

  The condenser 22 is a heat exchanger that cools and condenses the working medium from the expander 21. Specifically, the working medium and the cooling liquid (for example, seawater) are subjected to heat exchange to condense the working medium. Then, the working medium from the condenser 22 is sent again to the evaporator 20 via the circulation pump 23. At this time, in this embodiment, the temperature or pressure of the working medium at the outlet of the condenser 22 is detected by the sensor 29, and the feed water pump to the condenser 22 is maintained so that the detected temperature or detected pressure is maintained as desired. 30 is controlled to adjust the flow rate of the coolant supplied to the condenser 22.

  According to the fluid machine drive system 2 of the present embodiment, the compressor and the like are directly driven by the expander 21, so that no generator is required and it is not necessary to connect to the electrical system. Thereby, cost reduction can be aimed at rather than the case where a generator is used. Further, the efficiency is higher than when a compressor or the like is once driven instead of electricity. When the fluid machine driven by the expander 21 is a compressor, the efficiency can be further improved by recovering the compression heat.

  In the embodiment, the exhaust gas from the engine 3 is not directly exchanged heat with the working medium in the third heat exchanger 19 but is first exchanged with water in the exhaust gas boiler 16 and steam from the exhaust gas boiler 16 is exchanged. Was exchanged with the working medium in the third heat exchanger 19. This is because the working medium has an upper limit on the practical temperature in relation to its critical temperature. That is, since the exhaust gas from the engine 3 is too hot as it is, it may not be able to directly exchange heat with the working medium in the evaporator 20. In the case of the engine 3 using a fuel containing sulfur, it is necessary to consider the acid dew point of the exhaust gas. That is, if the exhaust gas and the working medium are directly heat-exchanged in the evaporator 20 and the exhaust gas temperature is lowered too much, the heat exchanger may be corroded. However, such inconvenience can be prevented by generating steam with exhaust gas heat using the exhaust gas boiler 16 and exchanging heat between the steam and the working medium using the third heat exchanger 19. However, in consideration of the above points, depending on the exhaust gas temperature, the type of fuel of the engine 3 and the type of working medium, the exhaust gas from the engine 3 may be directly exchanged with the working medium in the third heat exchanger 19. It may be good.

  The fluid machine drive system 2 of the present invention and the system to which the fluid machine drive system 2 is applied are not limited to the configuration of the above-described embodiment, and can be changed as appropriate. In particular, the system to which the fluid machine drive system 2 of the above embodiment is applied is not limited to the power system 1 of FIG. 1 and can be similarly applied to other various systems. Of course, it is not limited to the system installed in the ship.

  In the power system 1 of FIG. 1, the engine 3 is supplied with compressed air from the supercharger 15, but the supercharger 15 can be omitted in some cases. Even when a supercharger is used, the supercharger does not have to be the exhaust gas supercharger 15 that obtains compressed air using the energy of the exhaust gas, and even if the air compressor is driven without using the exhaust gas. Good.

  Furthermore, in the said Example, the example which uses any one, two, or all three among the 1st heat exchanger 13, the 2nd heat exchanger 18, and the 3rd heat exchanger 19 as the evaporator 20 is used. Although described, a heat exchanger other than these may be used as the evaporator 20 in some cases.

DESCRIPTION OF SYMBOLS 1 Power system 2 Fluid machine drive system 3 Engine 12 Jacket 13 First heat exchanger 15 Supercharger 16 Exhaust gas boiler 17 Air compressor 18 Second heat exchanger 19 Third heat exchanger 20 Evaporator 21 Expander 22 Condenser 23 Circulating pump 28 Fluid machinery

Claims (3)

An evaporator that heats and vaporizes the working medium using exhaust heat;
An expander that generates power using the working medium from the evaporator;
A condenser that cools and condenses the working medium from the expander;
A circulation pump for feeding the working medium from the condenser to the evaporator;
A fluid machine composed of a compressor, a blower or a pump and driven by the expander ;
An exhaust gas boiler that passes exhaust gas from the engine and generates steam using the exhaust gas heat,
A second heat exchanger of compressed air from the supercharger to the engine and the working medium, and a third heat exchanger of steam from the exhaust gas boiler and the working medium from the second heat exchanger, A fluid machine drive system, wherein the working medium is heated in order as an evaporator . The fluid machine drive system according to claim 1, further comprising a first heat exchanger as a jacket coolant of the engine and a working medium for the second heat exchanger as the evaporator . The engine is a diesel engine installed in a ship;
The fluid machine is an air compressor;
The fluid machine drive system according to claim 1 or 2 , wherein the condenser is a heat exchanger between the working medium and seawater.

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