JP2007092584A - Thermal power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal power generation system wherein a contact bearing with a minimum contact area is used, a turbine can be rotated for a long period of time without restriction of kinds of working medium, rotation can be smoothly started, and a problem of deterioration in whole efficiency caused by a troublesome control or electric consumption unlike electromagnetic support is eliminated, so that a cost is reduced and generating efficiency is good. <P>SOLUTION: By a collector 1 absorbing thermal energy, the working medium 3 is heated directly or indirectly, vapor of the working medium 3 is jetted from a nozzle 8, and the turbine 5 is rotary driven by high-pressure vapor from the nozzle 8. The rotation of the turbine 5 rotates a generator rotor 6A in a generator 6, and a generator starter part 6B disposed to face the generator rotor 6A generates electric power. A main shaft 7 connecting the turbine 5 with the generator rotor 6A is installed in a vertical direction, and a lower end of a main shaft 7 is supported by a pivot part 11, and an upper part of the main shaft 7 is supported by repulsion of permanent magnets 12, 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermoelectric generation system that converts thermal energy such as solar heat into electric energy.

As a conventional example of this type of thermal power generation system, a solar thermal power generation system is known in which a working medium is heated by solar heat, a turbine is rotated by high-pressure steam of the working medium, and a generator is generated by the rotation of the turbine. (For example, Patent Documents 1 to 3).
JP 2002-242893 A JP 2000-110515 A JP 2003-227315 A

In the solar thermal power generation system described above, since the obtained thermal energy is small and the energy density is low, an organic medium that easily vaporizes or an organic medium having a low boiling point (for example, ammonia, alternative chlorofluorocarbon, alcohol, acetone, etc.) is used as the working medium. . However, when such a working medium is used, there is a problem in that it is difficult to hold the lubricant for the bearing for rotating and supporting the turbine due to high heat, and long-term rotation is not possible.
As an example of measures for solving this problem, for example, it is conceivable to rotationally support the turbine using a dynamic pressure bearing or a foil bearing. However, in this case, since the bearing portion is in mechanical contact with the turbine in a rotation stopped state, there is a problem that the rotation starting torque is large and it is difficult to start the rotation.
In addition, it is possible to support the turbine in a completely non-contact state by using an electromagnet alone or a combination of an electromagnet and a permanent magnet. In this case, however, a controller for controlling the non-contact support is required. There is a problem in terms of cost. Another problem is that the power generation efficiency of the system is reduced by the amount of power consumed by the electromagnet.

There are also the following problems.
・ When a contact bearing is used, the contact area generates heat.
-The working medium remains in the unit consisting of the turbine and generator, and the working medium cannot be used effectively.
-The organic medium used as the working medium may deteriorate the coating of the coil of the generator stator and the mold resin protecting the coil, adversely affecting stable power generation performance.
-In solar thermal power generation, the thermal energy obtained is small and the energy density is low, so if the mass and moment of inertia of the turbine member are large, it is difficult to start rotation.
The thermoelectric power generation system is a system that generates power based on the temperature difference of the working medium. However, using a dedicated device for cooling the working medium increases the system cost.
-In the heat conversion system, the energy conversion efficiency is low when the temperature of the working medium is low.

  The object of the present invention is to make the contact area as small as possible while using a contact bearing, enabling long-term rotation of the turbine without being restricted by the type of working medium, enabling smooth start-up, and using an electromagnet support. It is an object to provide a thermoelectric power generation system that is low in cost and good in power generation efficiency, without the problem of a decrease in overall efficiency due to the complicated control and power consumption.

  In the thermoelectric generation system of the present invention, the working medium is directly or indirectly heated by the collector that absorbs thermal energy, the steam of the working medium is ejected from the nozzle, and the turbine is rotationally driven by the high-pressure steam from the nozzle. The turbine and the generator rotor are connected in a system in which the generator rotor in the generator is rotated by the rotation of the turbine, thereby generating power with a generator stator provided opposite to the generator rotor. The main shaft is installed in a vertical direction, the lower end of the main shaft is supported by a pivot portion, and the upper portion of the main shaft is supported by repulsion of a permanent magnet. This thermoelectric power generation system may be a solar thermal power generation system that uses solar heat as thermal energy.

According to this configuration, because the main shaft is rotatably supported, the main shaft is installed in the vertical direction, the lower end of the shaft is supported by the pivot portion, and the upper portion of the shaft is supported in a non-contact state by the repulsion of the permanent magnet. The contact area can be reduced while using a contact bearing. For this reason, there are fewer restrictions on the use of lubricants, and there is a problem with bearing lubrication even when using ammonia, alternative chlorofluorocarbons, alcohols, acetone, or other organic media that are easily vaporized, or organic solvents with low boiling points. It does not occur. As a result, the turbine can be rotated for a long time without being limited by the type of working medium.
In addition, since the lower end of the main shaft is supported by a pivot portion having a small contact area, and the upper portion of the main shaft is supported in a non-contact state by the repulsion of the permanent magnet, there is less rotational torque and wear, and energy loss can be reduced as much as possible. Rotation can be started smoothly.
Further, since the pivot portion and the permanent magnet are used for the support, a controller when using an electromagnet is not required, and the support structure for the main shaft is simplified, thereby reducing the cost. There is no problem of a decrease in overall efficiency due to the power consumption of the electromagnet.

In this invention, you may connect the main shaft which connects the said turbine and a generator rotor so that a turbine may become a lower part of a main shaft, and a generator rotor may be an upper part of a main shaft.
When the turbine is at the lower part and the generator rotor is at the upper part, it is difficult for the working medium flowing into the turbine to enter the generator side, and it is possible to prevent the generator from being deteriorated by the working medium. Further, the liquefied working medium can be used as a lubricant for the pivot portion, and it is not necessary to prepare a lubricant separately. The working medium liquefied after being ejected from the nozzle of the turbine may have means for storing around the pivot portion. Thereby, it becomes easy to use the liquefied working medium ejected from the nozzle of the turbine for lubrication of the pivot portion.

  In this invention, it is good also as what has a partition in a part between the rotation part and stationary part of the said generator. By providing a partition wall between the rotating part and stationary part of the generator, the insulating film on the surface of the coil in the generator stator and the coil mold resin that protects the coil are organic solvents that are the working medium. It is possible to avoid a situation in which stable power generation cannot be performed due to being violated by the like.

  In this invention, the turbine impeller may be made of a plastic material that is not affected by the working medium. If the turbine is made of a plastic material, the weight of the turbine is reduced, so that the turbine can be rotated even with a small jet pressure. Even if a plastic material is used for the turbine impeller, there is no problem as long as the material is not affected by the working medium. For example, the plastic material may be a PEEK material (polyether ether ketone material). The PEEK material is an engineering plastic excellent in heat resistance, flame retardancy, and chemical resistance, and is excellent in various aspects as a material for a turbine impeller.

  In the present invention, the turbine may liquefy the high-pressure steam by a cooling action accompanying expansion. When the working medium is cooled in the turbine as described above, a dedicated device for cooling the working medium is not necessary, and the cost can be reduced accordingly.

  In this invention, it is good also as what has a means to heat the said working medium. By further reheating the working medium heated by the collector with the heating means, the heating temperature of the working medium can be further increased to increase the vapor pressure, thereby increasing the energy conversion efficiency by the turbine.

  In the thermoelectric generation system of the present invention, the working medium is directly or indirectly heated by the collector that absorbs thermal energy, the steam of the working medium is ejected from the nozzle, and the turbine is rotationally driven by the high-pressure steam from the nozzle. The turbine and the generator rotor are connected in a system in which the generator rotor in the generator is rotated by the rotation of the turbine, thereby generating power with a generator stator provided opposite to the generator rotor. The main shaft is installed in the vertical direction, the lower end of the main shaft is supported by the pivot part, and the upper part of the main shaft is supported by the repulsion of the permanent magnet, so that the contact area can be made as small as possible while using the contact bearing. The turbine can be rotated for a long time without being restricted by the type of medium, and the rotation can be started smoothly. Without problems lowering of overall efficiency due to complicated control and power consumption in the case by the electromagnet support, it is an electrical efficient heat generation system at low cost.

  A first embodiment of the present invention will be described with reference to FIGS. This thermal power generation system is a solar thermal power generation system that converts solar heat, which is thermal energy, into electric energy and outputs the electric energy. As shown in FIG. 1, this thermoelectric generator system circulates a working medium 3 between a collector 1 that absorbs solar heat, a turbine unit 2 having a turbine 5 and a generator 6, and the collector 1 and the turbine 5. A medium circulation path 4.

  The working medium circulation path 4 was used for rotating the turbine 5 and the nozzle 8 for rotating the turbine 5 by injecting the steam of the working medium 3 heated directly by the collector 1 to the turbine 5 as high-pressure steam. And a pump 9 for circulating and supplying the working medium 3 to the collector 1. A tank (not shown) for storing the working medium 3 may be provided between the turbine 5 and the pump 9.

  The generator 6 of the turbine unit 2 includes a generator rotor 6A that is a rotating portion and a generator stator portion 6B that is a stationary portion. The turbine 5 and the generator rotor 6A are connected by a main shaft 7. The main shaft 7 is installed in the vertical direction so that the lower portion thereof becomes the turbine 5 and the upper portion thereof becomes the generator rotor 6A. The main shaft 7 in such a vertical posture is rotatable by supporting the lower end of the shaft with the pivot portion 11 (FIG. 2) and supporting the upper portion of the shaft with the repulsion of the permanent magnets 12 and 13. Specifically, the generator 6 is an axial gap generator, and a generator rotor 6A is provided on an outer peripheral portion of a thrust plate 7a which is a circular flange portion provided in the middle body portion of the main shaft 7. A pair of generator stator portions 6B and 6B are arranged opposite to each other with a predetermined gap in the axial direction across the rotor 6A. An impeller (not shown in FIG. 1) of the turbine 5 is connected to the lower end side of the main shaft 7. Thus, the rotation of the turbine impeller becomes the rotation of the generator rotor 6A, and power is generated by the generator stator portion 6B provided to face the generator rotor 6A. This power generation is controlled by the controller 10.

  2 shows an enlarged cross-sectional view of the turbine unit 2 in FIG. 1, and FIG. 3 shows a cross-sectional view taken along the line III-III in FIG. In FIG. 2, a cylindrical nozzle member 18 is fixedly installed on the outer periphery of a turbine impeller 5 a connected to the lower portion of the main shaft 7 through a minute gap. The nozzle member 18 is provided with a plurality of nozzles 8 penetrating toward the turbine blade 5aa of the turbine impeller 5a in the circumferential direction. The upper end portion of the nozzle member 18 is connected to the upstream portion of the working medium circulation path 4 through an air supply port 19, and the working medium 3 heated by the collector 1 flows into the nozzle member 18 through the air supply port 19. Has been.

  The pivot part 11 described above is provided at the center of the lower end of the unit housing jig 2 a of the turbine unit 2, and the surrounding wall 22 is provided on the outer peripheral side of the pivot part 11. The surrounding wall 22 is a means for accumulating the working medium 3 liquefied after being ejected from the nozzle 8 of the turbine 5 around the pivot portion 11. Thus, the liquefied working medium 3 collected around the pivot portion 11 becomes a lubricant for lubricating the pivot portion 11. On the outer peripheral side of the surrounding wall 22, an exhaust port 20 is provided through the unit housing 2 a to allow the working medium 3 that has given rotational energy to the turbine impeller 5 a to flow out to the downstream portion of the working medium circulation path 4. .

  The turbine 5 is made of a plastic material that is not affected by the working medium 3. In particular, the turbine impeller 5a and the turbine blade 5aa of the turbine 5 are made of the plastic material. As a plastic material in this case, for example, a PEEK material (polyether ether ketone material) is suitable. When the turbine 5 is made of a plastic material, the weight of the turbine 5 is reduced, so that the turbine 5 can be rotated even with a small jet power. Even if a plastic material is used, no trouble is caused by using a material that is not affected by the working medium 3. The PEEK material is an engineering plastic excellent in heat resistance, flame retardancy, and chemical resistance, and is excellent in various aspects as the material of the turbine 5.

  Of the permanent magnets 12 and 13 that support the upper portion of the main shaft 7, the first permanent magnet 12 is provided on the outer periphery of the main shaft 7 on the rotating side, and the second permanent magnet 13 is on the fixed side facing this. Provided on the inner periphery of the unit housing 2a. These permanent magnets 12 and 13 are arranged with their polar directions determined so that their opposing surfaces have the same magnetic pole. Thereby, a repulsive force acts in the radial direction perpendicular to the axis of the main shaft 7 between the first permanent magnet 12 and the second permanent magnet 13, and supports the upper portion of the main shaft 7 in the radial direction in a non-contact state. Here, three combinations of the first permanent magnet 12 and the second permanent magnet 13 are arranged in the axial direction.

  A partition wall 21 is provided in a part between the rotating portion and the stationary portion of the generator 6. Specifically, the surfaces of the generator stator portions 6B and 6B, which are stationary portions of the generator 6, are covered and protected by the partition walls 21. In this way, by covering and protecting with the generator stator portion 6B, it is possible to prevent the insulating film on the surface of the coil in the generator stator portion 6B from being damaged by an organic medium or the like that is the working medium 3 to prevent stable power generation. it can.

  Next, operation | movement of this solar thermal power generation system is demonstrated. The working medium 3 in the working medium circulation path 4 is directly heated by the collector 1 that absorbs solar heat to become high-pressure steam, and this high-pressure steam is injected through the nozzle 8 onto the turbine blade 5aa of the turbine 5. Thereby, the turbine 5 is rotationally driven. The generator rotor 6A is rotated by the rotation of the turbine 5, and electric power is generated by the generator stator portion 6B provided to face the generator rotor 6A. The working medium 3 that gives rotational energy to the turbine 5 is transported to the collector 1 by the pump 9. At this time, since the turbine 5 liquefies the high-pressure steam of the working medium 3 by the cooling action accompanying expansion, the working medium 3 completely returns to the liquid in the path from the turbine 5 to the pump 9. As a result, a dedicated device for cooling the working medium 3 becomes unnecessary, and the cost can be reduced accordingly.

Thus, in this solar thermal power generation system, in order to rotatably support the main shaft 7, the main shaft 7 is installed in the vertical direction, the lower end of the shaft is supported by the pivot portion 11, and the upper portion of the shaft is supported by the permanent magnets 12 and 13. Since it supports in a non-contact state, a contact area becomes very small, using a contact bearing. For this reason, there are fewer restrictions on the use of lubricants, and there is a problem with bearing lubrication even when using ammonia, alternative chlorofluorocarbons, alcohols, acetone, or other organic media that are easily vaporized, or organic solvents with low boiling points. It does not occur. As a result, the turbine 5 can be rotated for a long time without being restricted by the type of the working medium.
Further, since the lower end of the main shaft 7 is supported by the pivot portion 11 having a small contact area, and the upper portion of the main shaft 7 is supported in a non-contact state by the repulsion of the permanent magnets 12 and 13, there is less rotational torque and wear, and energy loss. Can be reduced as much as possible, and rotation can be started smoothly.
In addition, since the support by the pivot portion 11 and the permanent magnets 12 and 13 is not required, a controller when using an electromagnet is unnecessary, and the support structure of the main shaft 7 is simplified, thereby reducing the cost. There is no problem of a decrease in overall efficiency due to the power consumption of the electromagnet.

  Further, in this embodiment, the turbine 5 and the generator rotor 6A are connected by the vertically installed main shaft 7 so that the turbine 5 is the lower portion of the main shaft 7 and the generator rotor 6A is the upper portion of the main shaft 7. It is difficult for the working medium 3 flowing into the turbine 5 to enter the generator 6 side, and the working medium 3 can prevent the generator 6 from deteriorating.

  Further, since the surrounding wall 22 is provided around the pivot portion 11 supporting the lower end of the main shaft 7 as means for storing the working medium 3 liquefied after being ejected from the nozzle 8 of the turbine 5, the liquefaction operation stored in the surrounding wall 22 is provided. The pivot portion 11 can be lubricated by using the medium 3 as a lubricant, and there is no need to prepare a special lubricant for the pivot portion 11.

  Furthermore, in this embodiment, since the partition wall 21 is provided in a part between the rotating portion and the stationary portion of the generator 6, the insulating film on the surface of the coil in the generator stator portion 6B is the working medium 3. It is possible to avoid a situation where stable power generation cannot be performed due to being attacked by an organic solvent or the like.

  FIG. 4 shows another embodiment of the present invention. In this thermoelectric generation system, instead of the working medium circuit 4 in the embodiment of FIG. 1, the first working medium circuit 4 </ b> A that circulates the first working medium 3 </ b> A through the collector 1 and the second operation through the turbine 5. By providing the second working medium circulation path 4B for circulating the medium 3B and applying the heat amount of the first working medium 3A heated by the collector 1 to the second working medium 3B via the heat exchanger 23 The second working medium 3B is indirectly heated. The nozzle 8 and the pump 9 are provided in the second working medium circulation path 4B. Other configurations are the same as those in the first embodiment.

  Thus, by separating the working medium 3A for acquiring thermal energy from the collector 1 and the working medium 3B for driving the turbine 5, the working medium suitable for each role can be individually selected. The degree of freedom of selection can be expanded.

FIG. 5 shows still another embodiment of the present invention. In the first embodiment, the thermoelectric generation system is provided with a heater 14 as means for heating the working medium 3 in the middle of the path from the collector 1 of the working medium circulation path 4 to the turbine 5. The heater 14 may be provided in the collector 1. Other configurations are the same as those in the first embodiment.
In this way, by further heating the working medium 3 heated by the collector 1 with the heater 14, the heating temperature of the working medium 3 can be further increased to increase the vapor pressure, and the injection energy to the turbine 5 can be increased. Can be increased. Thereby, the energy conversion efficiency by the turbine 5 can be improved.

  In each of the above embodiments, the case where an axial gap generator is used as the generator 6 has been described, but a radial gap generator may be used. Moreover, although each said embodiment illustrated and demonstrated the case of the solar thermal power generation system which uses solar heat as a thermal energy, even if it applies to the thermoelectric power generation system which uses another heat source as a thermal energy, the same effect as the above is raised. be able to.

1 is a cross-sectional view showing a schematic configuration of a thermoelectric generator system according to a first embodiment of the present invention. It is an expanded sectional view of the turbine unit in the thermoelectric power generation system. It is the III-III arrow sectional drawing in FIG. It is sectional drawing which shows schematic structure of the thermoelectric power generation system concerning other embodiment of this invention. It is sectional drawing which shows schematic structure of the thermoelectric power generation system concerning further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Collector 2 ... Turbine unit 3, 3A, 3B ... Working medium 5 ... Turbine 6 ... Generator 6A ... Generator rotor 6B ... Generator stator part 7 ... Main shaft 8 ... Nozzle 14 ... Heater 21 ... Partition 22 ... Enclosure

Claims (10)

The working medium is heated directly or indirectly by a collector that absorbs thermal energy, the steam of the working medium is ejected from the nozzle, the turbine is rotated by the high-pressure steam from the nozzle, and the generator is generated by the rotation of the turbine. In the system for generating power by the generator stator portion provided to face the generator rotor by rotating the generator rotor in
A thermoelectric power generation system comprising: a main shaft connecting the turbine and the generator rotor is installed in a vertical direction; a lower end of the main shaft is supported by a pivot portion; and an upper portion of the main shaft is supported by repulsion of a permanent magnet. .   2. The thermoelectric generation system according to claim 1, wherein the main shaft that connects the turbine and the generator rotor is connected so that the turbine is located below the main shaft and the generator rotor is located above the main shaft.   The thermoelectric generation system according to claim 2, wherein the working medium is a lubricant that lubricates the pivot portion.   4. The thermoelectric generator system according to claim 3, further comprising means for storing a working medium liquefied after being ejected from a nozzle of the turbine around the pivot portion.   5. The thermoelectric generator system according to claim 1, further comprising a partition wall between a rotating portion and a stationary portion of the generator.   6. The thermoelectric generation system according to claim 1, wherein the turbine impeller is made of a plastic material that is not affected by the working medium.   The thermoelectric generation system according to claim 6, wherein the plastic material is a PEEK material.   The thermoelectric power generation system according to any one of claims 1 to 7, wherein the turbine liquefies high-pressure steam by a cooling action accompanying expansion.   8. The thermoelectric generation system according to claim 1, further comprising means for heating the working medium.   The thermoelectric power generation system according to any one of claims 1 to 9, wherein the thermal energy is solar heat.

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