JP2009138684A - Rankine cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ranking cycle device provided with an expander and a pump which are lubricated with lubricating oil, separately collecting the lubricating oil mixed into working fluid in the expander and pump and supplying the appropriate amount of lubricating oil to the expander and pump. <P>SOLUTION: This ranking cycle device 10 includes: a working fluid circulating circuit 20 formed by sequentially connecting a force feeding pump 2 forcibly feeding the working fluid, heaters (a regenerative heat exchanger 16 and an evaporator 5), the expander 1 and a condenser 6 through channels; an oil separator 11 separating the lubricating oil mixed into the working fluid in the expander 1 and force feeding pump 2 from the working fluid; an oil reservoir tank 12 reserving the lubricating oil; a first lubricating oil supplying passage 31 supplying the lubricating oil from the oil reservoir tank 12 to the expander 1; and a second lubricating oil supplying passage 32 supplying the lubricating oil from the oil reservoir tank 12 to the force feeding pump 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technology for separating and recovering lubricating oil mixed in a working fluid and supplying the lubricating oil to the expander and the pump in a Rankine cycle apparatus including an expander and a pump lubricated with the lubricating oil.

  2. Description of the Related Art Conventionally, there is known a Rankine cycle apparatus that recovers energy from a heat source such as waste heat by providing a working fluid circulation circuit in which a pressure pump, an evaporator, an expander, and a condenser are connected in order through a flow path. In general, among the fluid machines included in the Rankine cycle apparatus, those having a mechanical sliding portion such as a bearing are an expander and a pressure feed pump, and these mechanical sliding portions are lubricated with lubricating oil. However, the lubricating oil that lubricates the expander and the pressure feed pump is mixed into the working fluid passing therethrough and flows out. As a result, in the expander and the pressure feed pump, the efficiency resulting from the insufficient amount of lubricating oil Reduction and seizure occur. Therefore, Patent Document 1 proposes a technique for separating the lubricating oil from the working fluid and returning it to the expander, and Patent Document 2 discloses a technique for separating the lubricating oil from the working fluid and returning it to the expander and the pressure pump. Proposed.

  As shown in FIG. 8, the Rankine cycle device 100 described in Patent Document 1 lubricates the working fluid circulation circuit 20 including the evaporator 5, the expander 1, the condenser 6, and the pumping pump 2, and the expander 1. An oil passage 95 through which the lubricating oil circulates, a water separation means 96 provided in the oil passage 95 for separating water as the working fluid from the lubricating oil, and a gas disposed between the pressure feed pump 2 and the condenser 6. A bypass passage 93 that branches from the liquid separator 98 and bypasses the condenser 6 is provided, and an oil separation means 94 that is provided in the bypass passage 93 and separates the lubricating oil from the working fluid. In the Rankine cycle device 100, the working fluid is separated from the lubricating oil circulating in the oil passage 95 by the water separation means 96 and returned to the working fluid circulation circuit 20, and the working fluid circulation circuit 20 is obtained by the oil separation means 94. The lubricating oil is separated from the working fluid circulating through the refrigerant and returned to the expander 1.

As shown in FIG. 9, the Rankine cycle device 101 described in Patent Document 2 includes an oil supply passage 91 that communicates the outlet side of the expander 1 and the inlet side of the pressure feed pump 2 in the working fluid circulation circuit 20. The lubricating oil separated from the gas-phase working fluid in the oil storage chamber 92 provided in the oil supply passage 91 is utilized by utilizing the pressure difference between the back pressure on the expander 1 outlet side and the back pressure on the pumping pump 2 inlet side. Thus, it is supplied to the pressure feed pump 2. The expander 1 and the pressure pump 2 are integrated, and the lubricating oil supplied to the pressure pump 2 reaches the bearing of the pressure pump 2 via the bearing of the expander 1, and the expander 1 and the pressure pump. 2 is configured to lubricate both mechanical sliding portions.
JP 2003-97222 A JP 2006-329182 A

  FIG. 10 shows the relationship of the optimum lubricating oil flow rate (lubricating oil supply amount) with respect to the rotational speed of a general fluid machine. As shown in FIG. 10, the lubricating oil flow rate at which the fluid machine exhibits an optimal lubrication state is determined by the rotational speed, and the optimal lubricating oil flow rate increases as the rotational speed increases. If the amount of the lubricating oil is insufficient, the mechanical loss of the fluid machine is caused and the durability is lowered. On the other hand, if the amount of lubricating oil is excessive, the recovery power in the expander is reduced, the driving force of the pressure feed pump is increased, and further the lubricating oil content of the working fluid is increased. If the lubricating oil content of the working fluid increases, the heat exchanger (evaporator and condenser) reduces the heat exchange efficiency and causes energy loss due to heating or cooling of the lubricating oil. May adversely affect performance. In view of the above, in order to operate an expander and a pressure pump having different rotational speeds in an optimal lubrication state, it is necessary to individually supply an appropriate amount of lubricating oil to the expander and the pressure pump. There is.

  The Rankine cycle device 100 described in Patent Document 1 can lubricate the expander 1, but does not mention lubrication of the pump 2. In other words, there is no mention of a technique for lubricating both the mechanical sliding portions of the expander 1 and the mechanical sliding portions of the pressure feed pump 2 included in the Rankine cycle device. .

  In the Rankine cycle device 101 described in Patent Document 2, lubricating oil is supplied to the mechanical sliding parts of both the expander 1 and the pressure feed pump 2, and the lubricating oil supply path to these is a single path. It consists of That is, since the lubricating oil is supplied to the expander 1 and the pressure pump 2 through one path, the amount of lubricating oil supplied to these is the same, and the optimum lubricating oil is individually provided for each mechanical sliding portion. The amount cannot be supplied.

  The present invention has been made to solve the above-described problems. In the Rankine cycle apparatus, the mechanical sliding parts included in the fluid machines of the expander and the pressure feed pump are individually optimized. Provide technology for supplying the quantity of lubricant. Accordingly, it is an object of the present invention to improve the efficiency and durability of each fluid machine included in the Rankine cycle apparatus, thereby realizing an increase in the efficiency of the Rankine cycle apparatus.

  The Rankine cycle device according to the present invention includes a pressure pump that pumps a working fluid, a heater that heats the working fluid pumped from the pump, the pressure pump, and the working fluid that has been pressurized and heated by the heater. And an expander for taking out the motive power and a working fluid circulation circuit in which a condenser for cooling the working fluid whose temperature has been lowered and lowered by the expander is sequentially connected by a flow path, and is operated by the expander and the pressure feed pump. An oil separator that separates the lubricating oil mixed in the fluid from the working fluid, an oil storage tank that stores the lubricating oil separated by the oil separator, and supplies the lubricating oil from the oil storage tank to the expander A first lubricating oil supply path and a second lubricating oil supply path for supplying lubricating oil from the oil storage tank to the pumping pump are provided.

  In the Rankine cycle apparatus according to the present invention, the first lubricating oil supply path and the second lubricating oil supply path include a flow rate adjusting device that adjusts the flow rate of the lubricating oil.

  The present invention has the following effects.

  According to the Rankine cycle device of the present invention, an optimum amount of lubricating oil can be supplied to the expander and the pressure pump, respectively. By supplying an optimum amount of lubricating oil to each fluid machine of the expander and the pressure feed pump, it is possible to reduce the mechanical loss of each fluid machine. In addition, since the lubricating oil is stored in one oil storage tank without any shortage or unevenness, the management becomes easy, and the reliability of the device can be improved by stably supplying the lubricating oil to the expander and the pressure feed pump. it can. Further, since the amount of lubricating oil mixed in the working fluid can be minimized, it is possible to prevent the performance of heat exchangers such as an evaporator and a condenser from being deteriorated, and to improve the efficiency of the cycle.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted.

Embodiment 1

  Embodiment 1 of the present invention will be described. FIG. 1 is a diagram illustrating a configuration of a Rankine cycle device according to the first embodiment.

  As shown in FIG. 1, the Rankine cycle device 10 according to the first embodiment includes a working fluid circulation circuit 20 through which a working fluid circulates, and an oil separation and supply mechanism 30. In Rankine cycle device 10 according to the present embodiment, a natural refrigerant of carbon dioxide or water is used as the working fluid. Hereinafter, the structure of the working fluid circulation circuit 20 and the oil separation supply mechanism 30 will be described.

[Working fluid circulation circuit 20]
First, the configuration of the working fluid circulation circuit 20 will be described. The working fluid circulation circuit 20 is configured by sequentially connecting a pressure pump 2, a regenerative heat exchanger 16, an evaporator 5, an expander 1, and a condenser 6 through flow paths 21, 22, 23, 24, 25, and 26. ing. Between the regenerative heat exchanger 16 and the evaporator 5 on the high pressure side of the working fluid circulation circuit 20, an oil separator 11 provided in the oil separation and supply mechanism 30 for separating and removing the lubricating oil from the working fluid is provided. . Therefore, in more detail, the pressure feed pump 2 and the regenerative heat exchanger 16 are connected by the flow path 21, the regenerative heat exchanger 16 and the oil separator 11 are connected by the flow path 22, and the oil separator 11 and the evaporator 5 are connected. Are connected by a flow path 23, the evaporator 5 and the expander 1 are connected by a flow path 24, the expander 1 and the condenser 6 are connected by a flow path 25, and the condenser 6 and the pressure pump 2 are connected by a flow path. 26, a working fluid circulation circuit 20 that circulates the working fluid is configured.

  The pressure feed pump 2 is a pressure increase part of the Rankine cycle, and is rotationally driven by the motor 14 whose drive is controlled by the control device 50 to pump the working fluid to the regenerative heat exchanger 16. The control device 50 is a programmable logic controller or a computer, and is configured to control the operation of the motor 14 and the generator 4 described later in accordance with a preset program.

  The regenerative heat exchanger 16 is the first heating part (heater) of the Rankine cycle, and includes a working fluid from the outlet of the pressure pump 2 to the inlet of the expander 1 and from the outlet of the expander 1 to the inlet of the condenser 6. By exchanging heat with the working fluid, the working fluid discharged from the pressure pump 2 is heated, and the working fluid discharged from the expander 1 is cooled. The flow path 25 connecting the outlet of the expander 1 and the inlet of the condenser 6 includes a heat exchange flow path 28 that passes through the regenerative heat exchanger 16 in the middle. The working fluid discharged from the expander 1 to the flow path 25 flows into the heat exchange flow path 28, and while passing through the heat exchange flow path 28, the working fluid and heat discharged from the pressure pump 2 in the regenerative heat exchanger 16. Then, it returns to the flow path 25 and flows into the condenser 6.

  The evaporator 5 is a second heating part (heater) of the Rankine cycle, and the working fluid heated by the regenerative heat exchanger 16 is further heated to a high temperature and a high pressure by exchanging heat with a high temperature heat source. . As described above, the Rankine cycle apparatus 10 includes the two heaters of the regenerative heat exchanger 16 and the evaporator 5, and the working fluid is heated in stages.

  The expander 1 is an output extraction part of a Rankine cycle, expands the working fluid which became high temperature and high pressure, and converts the heat and pressure into mechanical energy. The mechanical energy taken out by the expander 1 is converted into electric energy by the generator 4 connected to the expander 1 by a power take-off shaft. The electrical energy extracted by the generator 4 is controlled by the control device 50.

  The condenser 6 is a Rankine cycle cooling unit, and further cools the working fluid that has been cooled and reduced in pressure by the expander 1 and cooled by the regenerative heat exchanger 16 by exchanging heat with a low-temperature heat source.

  Next, the flow of the working fluid in the working fluid circulation circuit 20 configured as described above will be described. The working fluid pressurized by the pressure pump 2 is heated through the regenerative heat exchanger 16, the lubricating oil content is reduced through the oil separator 11, and further heated through the evaporator 5 to become a high temperature. The working fluid that has become high temperature and high pressure expands through the expander 1 and its expansion energy is recovered as power to become low temperature and low pressure. The working fluid having a low temperature and a low pressure is cooled through the regenerative heat exchanger 16, further cooled through the condenser 6, and returned to the pumping pump 2.

[Oil separation supply mechanism 30]
Next, the configuration of the oil separation and supply mechanism 30 will be described. The oil separation and supply mechanism 30 includes an oil separator 11 disposed between the outlet of the regenerative heat exchanger 16 and the inlet of the evaporator 5 on the high pressure side of the Rankine cycle, and the lubricating oil separated and recovered by the oil separator 11. Oil storage tank 12 and lubricating oil supply passages 31 and 32 for supplying lubricating oil to the mechanical sliding portions of fluid machines 1 and 2 included in Rankine cycle device 10.

  The fluid machine included in the Rankine cycle device 10 is the expander 1 and the pressure feed pump 2, and the mechanical sliding portion is a portion lubricated with lubricating oil such as a bearing or a piston. In Rankine cycle apparatus 10 according to the present embodiment, PAG (polyalkylene glycol) is used as the lubricating oil. Lubricating oil flows into the cycle through a small gap in the mechanical sliding portion, and the lubricating oil is mixed into the working fluid while the working fluid passes through the expander 1 or the pressure feed pump 2.

  The oil separator 11 separates the lubricating oil from the working fluid mixed with the lubricating oil, returns the working fluid from which the lubricating oil has been separated and removed to the working fluid circulation circuit 20, and collects the lubricating oil separated from the working fluid. The oil is stored in the oil storage tank 12.

  As the oil separator 11, a centrifugal oil separator that separates the working fluid and the lubricating oil by using a density difference is used. The centrifugal oil separator is a device in which a working fluid mixed with lubricating oil is swirled in a container to separate oil droplets by centrifugal force. The separated lubricating oil is a lower part of the container of the oil separator 11. The working fluid recovered and separated from the lubricating oil flows out from the upper part of the container.

  The oil storage tank 12 includes a first lubricating oil supply passage 31 that supplies lubricating oil to the mechanical sliding portion of the expander 1, and a second lubricating oil that supplies lubricating oil to the mechanical sliding portion of the pressure feed pump 2. A supply path 32 is provided. The optimum lubricating oil flow rate for the mechanical sliding portion of the expander 1 and the optimum lubricating oil flow rate for the mechanical sliding portion of the pressure feed pump 2 have been determined in advance experimentally or theoretically. Depending on the oil flow rate, the flow areas of the first lubricating oil supply path 31 and the second lubricating oil supply path 32 are individually determined. Here, the “optimum lubricating oil flow rate” refers to the amount of lubricating oil supplied to the mechanical sliding portion without excess or deficiency so that the fluid machine operates optimally. In the Rankine cycle device 10, the expansion machine 1 normally has a higher rotational speed than the pumping pump 2, so that the optimum lubricating oil flow rate is larger (see FIG. 10). One lubricating oil supply passage 31 has a larger passage area.

  Next, the flow of lubricating oil in the oil separation and supply mechanism 30 will be described. The lubricating oil separated and recovered from the working fluid by the oil separator 11 is stored in the oil storage tank 12. The lubricating oil stored in the oil storage tank 12 is supplied to the mechanical sliding portion of the expander 1 through the first lubricating oil supply passage 31, and the mechanical sliding portion of the pressure feed pump 2 through the second lubricating oil supply passage 32. Supplied to. Thus, the lubricating oil supplied to the mechanical sliding portions of the fluid machines 1 and 2 flows out into the cycle through the minute gaps of the mechanical sliding portions and mixes with the working fluid. It is separated and recovered by the separator 11 and supplied to the mechanical sliding portion. Since the lubricating oil circulates in this way, it is not necessary to replenish the lubricating oil to the mechanical sliding portions of the fluid machines 1 and 2 of the Rankine cycle apparatus 10.

  Hereinafter, the features of the Rankine cycle apparatus 10 configured as described above will be described.

  In the Rankine cycle apparatus 10, the oil separator 11 is disposed on the high pressure side of the Rankine cycle. That is, the oil separator 11 is disposed between the outlet of the pressure pump 2 of the working fluid circulation circuit 20 and the inlet of the expander 1. Thereby, the lubricating oil separated from the working fluid by the oil separator 11 has a high pressure, and the oil storage tank 12 also has a high pressure. Therefore, the lubricating oil in the oil storage tank 12 flows through the lubricating oil supply passages 31 and 32 to each mechanical sliding portion without providing the oil storage tank 12 and the lubricating oil supply passages 31 and 32 with a pump or the like. Supplied. Therefore, the structure of the oil separation and supply mechanism becomes simple and can contribute to cost reduction.

  In the Rankine cycle apparatus 10, the oil separator 11 is disposed between the outlet of the regenerative heat exchanger 16 and the inlet of the evaporator 5. That is, the Rankine cycle apparatus 10 includes two heaters (the regenerative heat exchanger 16 and the evaporator 5), and the oil separator 11 is disposed between these heaters. With this configuration, since the working fluid has a reduced lubricating oil content before flowing into the evaporator 5, it is possible to prevent a decrease in heat exchange performance in the evaporator 5. Further, since the working fluid is heated by the regenerative heat exchanger 16 and flows into the oil separator 11 in a state where the density difference between the working fluid and the lubricating oil is larger, the working fluid and the lubricating oil are separated with higher accuracy. Is done. Compared to lubricating oil, the working fluid has a larger density decreasing rate with increasing temperature, and in the normal Rankine cycle operating temperature range (100 to 500 ° C.), the density difference between the working fluid and lubricating oil increases as the temperature increases. The oil separator 11 that uses the difference in density between the two to separate the oil has a good separation accuracy.

  Further, in the Rankine cycle device 10, independent lubricating oil supply paths 31 and 32 are provided for the mechanical sliding portions of the two fluid machines 1 and 2, respectively. This makes it possible to supply an optimal amount of lubricating oil to each mechanical sliding portion. Further, the flow rate of the lubricating oil is adjusted according to the flow passage areas of the lubricating oil supply passages 31 and 32, and an optimal amount of lubricating oil is supplied to each mechanical sliding portion. Therefore, the mechanical loss of the expander 1 and the pressure feed pump 2 due to insufficient lubrication can be reduced, and the performance degradation of the evaporator 5 and the condenser 6 due to excessive supply of lubricating oil can be prevented.

  In the Rankine cycle device 10, one oil storage tank 12 is provided. In this way, by using one oil storage tank 12 provided in the Rankine cycle device 10, it is possible to manage the lubricating oil in an integrated manner, and it is difficult for excess or deficiency in the amount of stored lubricant oil, and the Rankine cycle device. The bias of the lubricating oil storage amount that occurs when a plurality of oil storage portions are installed in 10 does not occur. Therefore, lubricating oil can be stably supplied with respect to each mechanical sliding part, the efficiency fall of the expander 1 and the pumping pump 2 can be prevented, and the reliability of operation | movement can be improved.

Embodiment 2

  A second embodiment of the present invention will be described. FIG. 2 is a diagram illustrating a configuration of a Rankine cycle device according to the second embodiment, and FIG. 3 is a diagram illustrating a relationship between a throttle amount of a flow path and a lubricating oil flow rate.

  As shown in FIG. 2, the Rankine cycle apparatus according to the second embodiment has the same configuration as that of the Rankine cycle apparatus according to the first embodiment, except for the lubricating oil supply path included in the oil separation and supply mechanism. Therefore, here, regarding the oil separation and supply mechanism, a lubricating oil supply path different from the first embodiment will be described in detail, and other description will be omitted.

  The oil separation and supply mechanism 30 includes an oil separator 11 disposed between the outlet of the regenerative heat exchanger 16 and the inlet of the evaporator 5 on the high pressure side of the Rankine cycle, and the lubricating oil separated and recovered by the oil separator 11. And a lubricating oil supply passage 33 for supplying lubricating oil to the mechanical sliding portions of the fluid machines 1 and 2 provided in the Rankine cycle device 10.

  A lubricating oil supply path 33 is connected to the oil storage tank 12. On the way, the lubricating oil supply path 33 is a first lubricating oil supply path 31 that supplies lubricating oil to the mechanical sliding portion of the expander 1 and a first lubricating oil that supplies lubricating oil to the mechanical sliding portion of the pressure feed pump 2. Branching into two lubricating oil supply paths 32. The first lubricating oil supply passage 31 and the second lubricating oil supply passage 32 are respectively provided with flow rate adjusting means 34 and 35 for adjusting the flow rate of the lubricating oil. A variable throttle mechanism is provided as the flow rate adjusting means 34, 35 so that the flow rate of the lubricating oil supplied to the expander 1 and the pressure feed pump 2 can be individually adjusted by adjusting the throttle amount of the lubricating oil supply passages 31, 32. It is configured. In the present embodiment, an electromagnetic proportional control type variable orifice whose flow area is changed by changing the input current under the control of the control device 50 is used as the variable throttle mechanism.

  FIG. 3 shows the relationship between the amount of flow restriction and the lubricating oil flow rate. As shown in FIG. 3, the throttle amount Ai of the flow path with respect to the lubricating oil flow rate Qi is uniquely determined, and the lubricating oil flow rate decreases as the throttle amount of the flow path increases. Therefore, if the relationship between the rotational speed of the fluid machine and the optimum lubricant flow rate for the mechanical sliding part of the fluid machine operating at the rotational speed is obtained experimentally or theoretically, the rotational speed of the fluid machine From the relationship with the optimum lubricating oil flow rate, the relationship between the rotational speed of the fluid machine and the throttle amount of the flow path can be derived.

  The expander 1 and the pressure feed pump 2 are provided with rotation speed sensors 1a and 2a that detect the rotation speed and transmit the detection signal to the control device 50, respectively. Further, the control device 50 obtains the relationship between the rotational speed and the optimum lubricating oil flow rate in advance experimentally or theoretically for the mechanical sliding portion of the expander 1 and the mechanical sliding portion of the pressure feed pump 2. The relationship between the derived number of rotations and the amount of restriction of the flow path, and the relationship between the amount of restriction of the flow path and the input current are stored. Further, the control device 50 is set with a program for controlling the input current to the variable orifice in accordance with the rotational speed detected by the rotational speed sensors 1a and 2a.

  In the above configuration, the control device 50 performs control to change the input current to the variable orifice in accordance with the rotational speed detected by the rotational speed sensors 1a and 2a. As a result, the throttle amount of the variable orifice is adjusted so that the optimum amount of lubricating oil is supplied to the mechanical sliding portions of the fluid machines 1 and 2. Therefore, since the optimum amount of lubricating oil is supplied to the mechanical sliding portions of the fluid machines 1 and 2 corresponding to the rotational speeds of the fluid machines 1 and 2, the mechanical sliding portions are always optimally lubricated. The state is maintained, and the mechanical loss of the fluid machines 1 and 2 can be reduced.

  In the present embodiment, the variable throttle mechanism is provided as the flow rate adjusting means 34, 35, but a fixed throttle in which the throttle amount of the flow path is fixed may be provided as the flow rate adjusting means 34, 35. In this case, from the relationship between the optimum lubricating oil flow rate of the mechanical sliding portion of each fluid machine 1 and 2 and the restriction amount of the flow path with respect to the optimum lubricating oil flow rate, a fixed amount having a restriction amount capable of supplying the optimum lubricating oil flow rate. A throttle is selected, and the fixed throttle is used as the flow rate adjusting means 34 and 35.

  Further, in the present embodiment, the variable throttle mechanism is provided as the flow rate adjusting means 34, 35, but an oil pump may be installed instead of the variable throttle mechanism. In this case, the relationship between the optimum lubricating oil amount with respect to the rotational speed of the fluid machines 1 and 2 and the relationship between the oil pump discharge amount with respect to the optimum lubricating oil amount are stored in the control device 50, and the control device 50 detects the detected fluid. It is configured to perform control to change the discharge amount of the oil pump in accordance with the rotational speed of the machines 1 and 2.

Embodiment 3

  Embodiment 3 of the present invention will be described. FIG. 4 is a diagram showing a configuration of the Rankine cycle apparatus according to the third embodiment, and FIG. 5 is a diagram showing a modification of the Rankine cycle apparatus according to the third embodiment.

  As shown in FIG. 4, the Rankine cycle apparatus according to the third embodiment has the same configuration as the Rankine cycle apparatus according to the first embodiment except for the oil separation and supply mechanism 30. Therefore, here, regarding the oil separation and supply mechanism 30, particularly the parts different from the first embodiment will be described in detail, and the other description will be omitted.

  The oil separation supply mechanism 30 stores the oil separator 11 disposed between the outlet of the expander 1 and the inlet of the condenser 6 on the low pressure side of the Rankine cycle, and the lubricating oil separated and recovered by the oil separator 11. The oil storage tank 12, the oil passage 38 for sending the lubricating oil from the oil separator 11 to the oil storage tank 12, the pressurizing pump 39 provided in the oil passage 38, and the Rankine cycle device 10 from the oil storage tank 12. Provided with lubricating oil supply passages 31 and 32 for supplying lubricating oil to the mechanical sliding portions of the fluid machines 1 and 2.

  The oil separator 11 is disposed on the low pressure side of the Rankine cycle, that is, between the outlet of the expander 1 and the inlet of the pressure pump 2 in the working fluid circulation circuit 20. Two heat exchangers, a regenerative heat exchanger 16 and a condenser 6, are provided on the low pressure side of the Rankine cycle. In the heat exchanger, the lower the lubricating oil content of the working fluid, the better the heat exchange efficiency. For this reason, it is preferable to reduce the lubricating oil content by removing the lubricating oil from the working fluid before flowing into these heat exchangers. Therefore, the oil separator 11 is provided in the working fluid circulation circuit 20 on the low pressure side of the Rankine cycle and between the outlet of the expander 1 and the inlet of the regenerative heat exchanger 16. However, since the oil separator 11 may be disposed between the outlet of the expander 1 and the inlet of the condenser 6 in the working fluid circulation circuit 20, the outlet of the regenerative heat exchanger 16 and the inlet of the condenser 6 An oil separator 11 may be provided between them.

  In a general Rankine cycle device, the working fluid discharged from the expander 1 is a gas phase, and the lubricating oil mixed in the working fluid is a liquid phase. 20, the density difference between the working fluid and the lubricating oil is relatively large between the expander 1 and the regenerative heat exchanger 16 (condenser 6). Since the oil separator 11 is a mechanism for separating the working fluid and the lubricating oil by using the density difference, the oil separator disposed between the expander 1 and the regenerative heat exchanger 16 (condenser 6). 11, the working fluid and the lubricating oil can be separated with higher accuracy.

  The lubricating oil separated and recovered from the working fluid by the oil separator 11 is sent to the oil storage tank 12 through the oil passage 38 and stored. Since the oil separator 11 is disposed on the low pressure side of the Rankine cycle, the lubricating oil separated and recovered by the oil separator 11 is also at a low pressure. Therefore, the lubricating oil stored in the oil storage tank 12 is equal to or higher than the pressure on the high pressure side of the Rankine cycle by being pressurized by the pressurizing pump 39 while the lubricating oil passes through the oil passage 38. Increased to pressure. Since the lubricating oil stored in the oil storage tank 12 is the same pressure as or higher than the pressure on the high-pressure side of the Rankine cycle, the lubricating oil supply passages 31 and 32 are not required without pumping means such as a pump. To the mechanical sliding parts of the fluid machines 1 and 2.

  As a modification of the present embodiment, as shown in FIG. 5, instead of providing a pressurizing pump 39 in the oil passage 38 connecting the oil separator 11 and the oil storage tank 12, the first lubricating oil supply Metering pumps 44 and 45 may be provided in the passage 31 and the second lubricating oil supply passage 32, respectively. In this case, although the lubricating oil stored in the oil storage tank 12 is at a low pressure, the fluid machinery 1 is adjusted through the lubricating oil supply passages 31 and 32 by increasing the pressure of the lubricating oil and adjusting the flow rate by the metering pumps 44 and 45. , 2 can be supplied with an optimum amount of lubricating oil.

Embodiment 4

  Embodiment 4 of the present invention will be described. FIG. 6 is a diagram showing a configuration of a Rankine cycle device according to the fourth embodiment.

  As shown in FIG. 6, the Rankine cycle apparatus 10 according to the fourth embodiment has the same configuration as the Rankine cycle apparatus according to the first embodiment except for the oil separation and supply mechanism 30. Therefore, here, regarding the oil separation and supply mechanism 30, particularly the parts different from the first embodiment will be described in detail, and the other description will be omitted.

  The oil separation supply mechanism 30 includes a first oil separator 11a disposed between the outlet of the regenerative heat exchanger 16 and the inlet of the evaporator 5 on the high pressure side of the Rankine cycle, and the expander on the low pressure side of the Rankine cycle. A second oil separator 11b disposed between one outlet and the inlet of the condenser 6, an oil storage tank 12 for storing lubricating oil separated and recovered by these oil separators 11a and 11b, An oil passage 38 for sending lubricating oil from the second oil separator 11b to the oil storage tank 12, a pressure pump 39 provided in the oil passage 38, and a fluid machine 1 provided in the Rankine cycle device 10 from the oil storage tank 12 , 2 are provided with lubricating oil supply passages 31, 32 for supplying lubricating oil to the mechanical sliding portions.

  The first oil separator 11 a is provided on the high pressure side of the Rankine cycle, that is, between the outlet of the pressure feed pump 2 and the inlet of the expander 1 in the working fluid circulation circuit 20. The working fluid circulation circuit 20 is provided with a regenerative heat exchanger 16 and an evaporator 5 as heat exchangers on the high pressure side, and the first oil separator 11a is disposed between these heat exchangers. ing. By disposing the first oil separator 11a in this way, the lubricating oil content of the working fluid flowing into the evaporator 5 is reduced to prevent a reduction in heat exchange efficiency, and the first oil separator 11a. By increasing the density difference between the working fluid and the lubricating oil by heating the working fluid flowing into the regenerative heat exchanger 16, the separation accuracy in the first oil separator 11 a is improved.

  The second oil separator 11b is provided on the low pressure side of the Rankine cycle, that is, between the outlet of the expander 1 and the inlet of the pressure pump 2 in the working fluid circulation circuit 20. The working fluid circulation circuit 20 is provided with a regenerative heat exchanger 16 and a condenser 6 as heat exchangers on the low pressure side, and the second oil separator 11 b is connected between the expander 1 and the regenerative heat exchanger 16. Arranged between. By arranging the second oil separator 11b in this manner, the lubricating oil content of the working fluid flowing into the regenerative heat exchanger 16 and the condenser 6 is reduced, thereby preventing a reduction in heat exchange efficiency.

The lubricating oil separated and recovered from the working fluid by the second oil separator 11b is sent to the oil storage tank 12 through the oil passage 38 and stored. As the lubricating oil passes through the oil passage 38, the pressure is increased by the pressurizing pump 39 to a pressure equal to or higher than the pressure on the high-pressure side of the Rankine cycle. The lubricating oil separated and recovered from the working fluid by the first oil separator 11 a and the second oil separator 11 b and stored in the oil storage tank 12 is expanded through the first lubricating oil supply path 31. 1 is supplied to the mechanical sliding portion 1, and is supplied to the mechanical sliding portion of the pressure feed pump 2 through the second lubricating oil supply passage 32.

In the Rankine cycle apparatus 10 according to the present embodiment, the oil separators 11a, 11a, An oil separator 11b is provided. Therefore, the working fluid having a reduced lubricating oil content flows into the heat exchanger provided in the working fluid circulation circuit 20, and a reduction in the efficiency of heat exchange in the heat exchanger can be prevented.

Embodiment 5

  Embodiment 5 of the present invention will be described. FIG. 7 is a diagram showing a configuration of a Rankine cycle device according to the fifth embodiment.

  As shown in FIG. 7, the Rankine cycle device 10 according to the fifth embodiment includes a working fluid circulation circuit 20 that circulates a working fluid and extracts energy, and mechanical sliding of a fluid machine included in the Rankine cycle device 10. And an oil separation and supply mechanism 30 that separates and collects lubricating oil mixed in the working fluid from the section and supplies the lubricating oil to the mechanical sliding section.

  First, the configuration of the working fluid circulation circuit 20 will be described. The working fluid circulation circuit 20 is configured by sequentially connecting a pressure pump 2, a regenerative heat exchanger 16, an evaporator 5, an expander 1, and a condenser 6 through flow paths 21, 22, 23, 24, 25, and 26. ing. In the working fluid circulation circuit 20, a sealed container 41 and an oil separator 11 disposed in the sealed container 41 are provided between the regenerative heat exchanger 16 and the evaporator 5. Further, the flow path 25 connecting the expander 1 and the condenser 6 includes a heat exchange flow path 28 for passing through the regenerative heat exchanger 16 on the way, and is discharged from the expander 1 to the flow path 25. The applied working fluid flows into the heat exchange flow path 28, passes through the regenerative heat exchanger 16, returns to the flow path 25, and flows into the condenser 6.

  The power shaft of the expander 1 and the power shaft of the pressure feed pump 2 are connected to one shaft by a transmission shaft 40, and the power recovered when the working fluid expands in the expander 1 is used for driving the pressure feed pump 2. Is done. Thus, since the pumping pump 2 is driven by the power recovered by the expander 1, the Rankine cycle is highly efficient, and the apparatus is simplified and reduced in size as compared with the case where the pumping pump 2 is driven by the motor. Can be achieved. Further, the generator 4 is provided on the transmission shaft 40, and the power recovered when the working fluid expands in the expander 1 is converted into electric energy by the generator 4 and taken out.

  Next, the configuration of the oil separation and supply mechanism 30 will be described. The oil separation and supply mechanism 30 includes an oil separator 11, an oil storage tank 12, a first lubricating oil supply path 31, and a second lubricating oil supply path 32. The oil separator 11 is a centrifugal oil separator that separates the lubricating oil mixed in the working fluid from the working fluid, and the lubricating oil separated and recovered by the oil separator 11 is stored in the oil storage tank 12. Stored. The oil storage tank 12 includes a first lubricating oil supply passage 31 that supplies lubricating oil from the oil storage tank 12 to the mechanical sliding portion of the expander 1, and a mechanical sliding portion of the pressure feed pump 2 from the oil storage tank 12. And a second lubricating oil supply passage 32 for supplying lubricating oil to

  In the above, the expander 1, the pressure pump 2, the generator 4, the oil separator 11, the oil storage tank 12, the first lubricating oil supply path 31 and the second lubricating oil supply path 32 are provided in the sealed container 41. ing. The working fluid heated by the regenerative heat exchanger 16 flows into the sealed container 41 through the flow path 22, and the inside of the sealed container 41 is filled with the working fluid. The inside of the sealed container 41 is communicated with the inlet of the oil separator 11, and the outlet of the oil separator 11 is connected to the inlet of the evaporator 5 through the flow path 23.

  As described above, since the oil separation and supply mechanism 30 is provided in the sealed container 41, the outer container of the oil separator 11 and the oil storage tank 12 can be eliminated, thereby reducing the cost and downsizing the entire apparatus. Can be planned. The oil separator 11 is provided between the inside of the sealed container 41 and the evaporator 5 in the working fluid circulation circuit 20, but is provided between the regenerative heat exchanger 16 and the inside of the sealed container 41. You can also. Moreover, although the oil separator 11 is arrange | positioned in the airtight container 41, the airtight container 41 itself may be provided with a lubricating oil separation function, or the oil separator 11 may be arranged outside the airtight container 41. it can.

  The sealed container 41 is filled with a working fluid having a temperature higher than the atmospheric temperature flowing out from the regenerative heat exchanger 16, and the difference between the member temperature of the expander 1 and the surrounding temperature is determined by the member of the expander 1. Since it can be made smaller than the temperature difference between the temperature and the atmospheric temperature, it is possible to reduce heat loss due to heat radiation from the expander 1. Furthermore, since the heat energy released by the expander 1 can be used for heating the working fluid, the heat loss of the entire cycle can be reduced.

  Here, the flow of the working fluid of the Rankine cycle device 10 configured as described above will be described. The working fluid pressurized by the pressure feed pump 2 is heated through the regenerative heat exchanger 16 and then flows into the sealed container 41. The working fluid that has flowed into the sealed container 41 is further heated through the evaporator 5 and becomes high temperature after the lubricating oil mixed therein is separated through the oil separator 11 disposed in the sealed container 41. The working fluid that has reached a high temperature and a high pressure is expanded through the expander 1, and this expansion energy is used for driving the pumping pump 2 and generating power by the generator 4. The low-temperature and low-pressure working fluid flowing out from the expander 1 is cooled by exchanging heat with the working fluid on the high-pressure side through the regenerative heat exchanger 16, and further cooled through the condenser 6. And return to the pressure pump 2.

  Next, the flow of the lubricating oil in the Rankine cycle device 10 will be described. The lubricating oil separated from the working fluid by the oil separator 11 is stored in the oil storage tank 12. The lubricating oil stored in the oil storage tank 12 is supplied to the mechanical sliding portion of the expander 1 through the first lubricating oil supply path 31, and the mechanical sliding of the pressure feed pump 2 through the second lubricating oil supply path 32. Supplied to the department. The lubricating oil supplied to the mechanical sliding portion in this way flows out into the cycle from the minute gap of the mechanical sliding portion and mixes with the working fluid.

  The Rankine cycle apparatus of the present invention has an expander and a pressure pump that are lubricated with lubricating oil, and is useful as, for example, a Rankine cycle apparatus provided in a solar thermal power generation system, an automobile waste heat energy regeneration system, and the like.

It is a figure which shows the structure of the Rankine cycle apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the structure of the Rankine cycle apparatus which concerns on Embodiment 2. FIG. It is a figure which shows the relationship between the amount of throttles of a flow path, and lubricating oil flow volume. It is a figure which shows the structure of the Rankine cycle apparatus which concerns on Embodiment 3. FIG. It is a figure which shows the modification of the Rankine-cycle apparatus which concerns on Embodiment 3. FIG. It is a figure which shows the structure of the Rankine cycle apparatus which concerns on Embodiment 4. FIG. It is a figure which shows the structure of the Rankine cycle apparatus which concerns on Embodiment 5. FIG. It is a figure which shows the structure of the conventional Rankine cycle apparatus. It is a figure which shows the structure of the conventional Rankine cycle apparatus. It is a figure which shows the relationship between the rotation speed of a fluid machine, and the optimal lubricating oil flow volume.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Expander 2 Pumping pump 4 Generator 5 Evaporator 6 Condenser (second heater)
DESCRIPTION OF SYMBOLS 10 Rankine cycle apparatus 11 Oil separator 12 Oil storage tank 14 Motor 16 Regenerative heat exchanger (1st heater)
DESCRIPTION OF SYMBOLS 20 Working fluid circulation circuit 28 Heat exchange flow path 30 Oil separation supply mechanism 31 1st lubricating oil supply path 32 2nd lubricating oil supply path 34,35 Flow rate adjustment means 50 Control apparatus

Claims (14)

A pump that pumps the working fluid, a heater that heats the working fluid pumped from the pump, an expander that expands the working fluid that has been pressurized and heated by the pump and the heater, and extracts its power, And a working fluid circulation circuit in which a condenser for cooling the working fluid whose temperature has been lowered and lowered by the expander is sequentially connected in a flow path;
An oil separator that separates lubricating oil mixed in the working fluid by the expander and the pressure pump from the working fluid;
An oil storage tank for storing lubricating oil separated by the oil separator;
A first lubricating oil supply path for supplying lubricating oil from the oil storage tank to the expander;
A second lubricating oil supply path for supplying lubricating oil from the oil storage tank to the pumping pump,
Rankine cycle equipment. The oil separator is disposed between the outlet of the pressure pump and the inlet of the expander in the working fluid circulation circuit.
The Rankine cycle apparatus according to claim 1. The working fluid circulation circuit includes a plurality of the heaters in series, and the oil separator is disposed between the heaters.
The Rankine cycle apparatus according to claim 1 or 2. At least one of the plurality of heaters is a regeneration unit that exchanges heat between the working fluid from the outlet of the pumping pump to the inlet of the expander and the working fluid from the outlet of the expander to the inlet of the condenser. A heat exchanger,
The Rankine cycle apparatus according to claim 3. The oil separator is disposed between the outlet of the expander and the inlet of the condenser in the working fluid circulation circuit.
The Rankine cycle apparatus according to claim 1 or 2. The oil passage for sending the lubricating oil separated by the oil separator to the oil storage tank has a lubricating oil pressurizing pump.
The Rankine cycle apparatus according to claim 5. The first lubricating oil supply path and the second lubricating oil supply path are provided with a flow rate adjusting device for adjusting the flow rate of the lubricating oil,
The Rankine cycle apparatus according to any one of claims 1 to 6. The flow rate adjusting device is a fixed throttle that sets the flow path area of the lubricating oil to a predetermined value.
The Rankine cycle apparatus according to claim 7. The flow rate adjusting device is a variable throttle mechanism capable of changing the throttle amount.
The Rankine cycle apparatus according to claim 7. The flow rate adjusting device is a metering pump that sends out a predetermined amount of lubricating oil,
The Rankine cycle apparatus according to claim 7. Power shafts of the expander and the pressure pump are connected,
The Rankine-cycle apparatus as described in any one of Claims 1-10. The expander and the pumping pump are provided in one sealed container,
The Rankine cycle apparatus according to any one of claims 1 to 11. The inside of the sealed container forms a part of a flow path from the outlet of the pressure pump to the inlet of the expander in the working fluid circulation circuit, and is filled with the working fluid.
The Rankine cycle apparatus according to claim 12. The working fluid is a natural refrigerant of water or carbon dioxide,
The Rankine-cycle apparatus as described in any one of Claims 1-13.

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