JP2011140899A - Method of modifying gas turbine plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost, space-saving and highly-efficient gas turbine plant in reference to modification of the existing uniaxial gas turbine plant. <P>SOLUTION: The existing uniaxial gas turbine is replaced with a biaxial gas turbine including a compressor 1 compressing air to generate compressed air, a combustor 2 generating combustion gas by mixing and burning the compressed air compressed by the compressor 1 and fuel, a high-pressure turbine 3 rotatively driven by the combustion gas generated by the combustor 2 and a low-pressure turbine 4 rotatively driven by gas discharged from the high-pressure turbine 3, and rotatably supported by a plurality of bearings. Members used in the existing uniaxial gas turbine are utilized in at least a part of a lubricating oil device such as a lubricating oil tank and a lubricating oil pump to supply lubricating oil to the bearings of the biaxial gas turbine. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for remodeling a two-shaft gas turbine for replacing an existing single-shaft gas turbine with a two-shaft gas turbine in which a compressor driving high-pressure turbine and an output low-pressure turbine have different shaft configurations. .

  There are two types of industrial gas turbines depending on the application. One is a single-shaft gas turbine in which a high-pressure turbine and a low-pressure turbine are connected on the same shaft in order to operate at a constant rotational speed for power generation. The other is a two-shaft gas turbine that is used for driving a machine in a natural gas pipeline or the like and is divided into two (two-shaft) rotating shafts. Generally, the turbine is divided into a high pressure turbine and a low pressure turbine. For example, Patent Document 1 discloses a two-shaft gas turbine in which a high-pressure turbine that drives a compressor and a low-pressure turbine that drives a generator, a pump, and the like have different shaft configurations.

  In the two-shaft gas turbine, the compressor and the high-pressure turbine can be rotated at high speed even when the rotational speed of a driven machine such as a pump or a screw compressor is low. Therefore, it is possible to increase the torque in the low speed range of the low pressure turbine. In that respect, the two-shaft gas turbine is often used for driving a machine such as a pump or a screw compressor. In addition, it can be used for power generation in which a generator is driven by a low-pressure turbine.

  Further, for example, Patent Document 2 discloses a gas turbine configuration that is remodeled to a configuration of a two-shaft gas turbine by using a medium pressure turbine of a regenerative one-shaft three-stage turbine as an output turbine and improves partial load efficiency. Has been.

JP-A-5-18271 JP-A-3-290024

  When replacing an existing single-shaft gas turbine plant, it is difficult to provide a gas turbine with improved performance after solving problems of cost and space.

  It is an object of the present invention to provide a gas turbine plant that is highly efficient with low cost and space, with respect to modification of an existing single-shaft gas turbine plant.

  To achieve the above object, the present invention is a uniaxial gas in which a rotating shaft is rotatably supported by a plurality of bearings, in which fuel is mixed with compressed air and burned, and a turbine is driven by high-temperature and high-pressure combustion gas. A lubricating oil device having a turbine, a lubricating oil tank, a lubricating oil pump, and a lubricating oil cooler; a lubricating oil supply system that supplies lubricating oil from the lubricating oil device to the plurality of bearings; and A gas turbine plant remodeling method comprising: a lubricating oil discharge system that collects lubricating oil into a lubricating oil device; and a compressor that generates compressed air by compressing air in the single-shaft gas turbine, and the compressor A combustor that generates a combustion gas by mixing and combusting the compressed air compressed by the fuel and the fuel, a high-pressure turbine that is rotationally driven by the combustion gas generated by the combustor, and a gas that is discharged from the high-pressure turbine. A two-shaft gas turbine having a low-pressure turbine to be driven and rotatably supported by a plurality of bearings, and lubricating the bearings of the two-shaft gas turbine using at least a part of the lubricating oil device Configure to supply oil.

  According to the present invention, it is possible to provide a highly efficient gas turbine plant with low cost and space-saving with respect to modification of an existing single-shaft gas turbine plant.

1 is a system configuration diagram of a two-shaft gas turbine that is one embodiment of the present invention. FIG. 1 is a cross-sectional view of a directly lubricated journal bearing that is one embodiment of the present invention. The perspective view of the tilting pad of the direct lubrication type bearing which is one of the embodiment of this invention. 1 is a system configuration diagram of a two-shaft gas turbine that is one embodiment of the present invention. FIG. 1 is a system configuration diagram of a two-shaft gas turbine that is one embodiment of the present invention. FIG. 1 is a system configuration diagram of a two-shaft gas turbine that is one embodiment of the present invention. FIG. 1 is a system configuration diagram of a two-shaft gas turbine that is one embodiment of the present invention. FIG.

  When remodeling an existing single-shaft gas turbine plant, the inventors came up with the knowledge that a high-efficiency gas turbine plant could be realized by replacing the existing single-shaft gas turbine with a two-shaft gas turbine. . This is because even when the rotational speed on the low-pressure turbine side is low, the characteristic of the two-shaft gas turbine that the rotational speed on the compressor side can be increased can be utilized. The reason will be described below.

  Usually, the output at the power plant is limited by the authorized output. Even when remodeling from a single-shaft type to a two-shaft type gas turbine, it is necessary to operate at or below this approved output. In the replacement of a gas turbine, when a gas turbine of the same output band is newly installed, the efficiency of the gas turbine is inevitably increased due to technological progress. For this reason, if the gas turbine in the same output band is operated in the same manner as before the modification, there is a possibility that a power generation output exceeding the authorized output may be generated. On the other hand, when the scale is reduced by rotating the gas turbine at a high speed in consideration of the output improvement due to the high efficiency of the gas turbine, it is necessary to provide a speed reducer between the gas turbine and the generator. This leads to a decrease in efficiency.

  Therefore, in the replacement of the gas turbine, by changing from a single-shaft type to a two-shaft type, the power turbine side is made the same rotation speed as the generator, eliminating the need for a speed reducer, and the gas generator side reducing the scale by high-speed rotation By doing so, the compressor suction flow rate can be reduced, and the gas turbine output can be limited to the authorized output or less. Furthermore, the rotation speed can be freely selected on the gas generator side so that the optimum efficiency of the compressor can be achieved, and high efficiency of the gas turbine can be achieved. In addition, since there is no need to provide a reduction gear between the power turbine and the generator, the efficiency of the gas turbine can be improved without gear loss that is a reduction gear loss. Even when a reduction gear is used, since the reduction ratio can be reduced, there are advantages in cost reduction and efficiency improvement.

  However, when replacing a single-shaft gas turbine with a twin-shaft gas turbine, it is generally necessary to replace most equipment including auxiliary equipment, which is disadvantageous in terms of cost and space. Among these, the cost for replacing the lubricating oil system is particularly great.

  Therefore, paying attention to the lubricating oil system, the difference in configuration between the single-shaft gas turbine and the two-shaft gas turbine will be described.

  A single-shaft gas turbine used for power generation is configured to mix and burn fuel with compressed air compressed by a compressor, and drive the turbine with high-temperature and high-pressure combustion gas. The rotational energy of the driven turbine is converted to electrical energy by a generator coupled to the turbine. Both ends of the single-shaft gas turbine rotor are rotatably supported by two journal bearings. In addition, a thrust bearing is provided on the compressor side.

  On the other hand, the two-shaft gas turbine includes a gas generator and a power turbine. The gas generator is connected to the compressor that compresses the intake air to generate compressed air, the combustor that mixes and burns compressed air and fuel, and the compressor on the same shaft, and is driven to rotate by the combustion gas from the combustor. And a high-pressure turbine having a high-pressure turbine rotor. The power turbine is composed of a low-pressure turbine including a low-pressure turbine rotor that is connected to load equipment such as a generator, a compressor, and a pump, and is driven to rotate by combustion gas that has passed through the high-pressure turbine. The high-pressure turbine rotor is rotatably supported by a journal bearing installed between the compressor and the high-pressure turbine, and a journal bearing installed on the opposite side in the axial direction from the high-pressure turbine with the compressor as the center. The low pressure turbine rotor is rotatably supported by two journal bearings installed between the low pressure turbine and the generator or the load device. As a result, the gas generator and the power turbine are supported by a total of four journal bearings. A thrust bearing is provided on the upstream side of the compressor and between the low-pressure turbine and the generator or load device.

  When an existing single-shaft gas turbine is remodeled into a two-shaft gas turbine for the purpose of higher output and higher efficiency, the number of bearings that support the high-pressure turbine rotor and the low-pressure turbine rotor increases. The bearing of an industrial gas turbine is generally a sliding bearing. Lubricating oil is supplied to and discharged from the bearing, and the bearing surface is lubricated to suppress an increase in bearing metal temperature. Therefore, auxiliary equipment such as a lubricating oil tank, a lubricating oil pump, a lubricating oil filter, a lubricating oil supply / discharge system, a lubricating oil cooler, and a lubricating oil cooling water system are required. If the auxiliary equipment is strengthened in response to the increase in the total amount of lubricating oil required as the number of bearings increases as a result of the modification to the twin-shaft gas turbine, the installation space for the auxiliary equipment will increase, In addition to the turbine, the design and development period of the auxiliary equipment is further increased, and the cost is increased.

  On the other hand, if the amount of lubricating oil in the existing lubricating oil device is maintained against the doubled number of bearings, the amount of lubricating oil supplied to one bearing is reduced. When the amount of lubricating oil is reduced, the bearing metal surface temperature and the oil film temperature of the lubricating surface increase, and the bearing pad surface may be damaged. Further, there is a concern that the unstable shaft vibration of the gas turbine may increase due to a decrease in viscosity of the lubricating oil or a decrease in damping due to a rise in the temperature of the bearing.

  In addition, if the lubricating oil system is changed in response to the increase in the number of bearings, the cost increases and installations are made by modifying auxiliary equipment such as a lubricating oil tank, lubricating oil pump, filter, and cooling oil cooling system such as a cooling tower. Space may be expanded. In the case of replacement of a gas turbine, it is desirable to use equipment other than the gas turbine in consideration of the reliability of equipment and equipment, equipment cost, and installation space.

  Hereinafter, a modification method for replacing an existing single-shaft gas turbine with a two-shaft gas turbine will be described through each embodiment. The reliability of the gas turbine is maintained by making the bearing device compatible with a reduction in the amount of lubricating oil supplied to each bearing device due to an increase in the number of bearings. Furthermore, it is an example of replacement of a gas turbine that can improve the plant output and efficiency by making two shafts, and can reduce the equipment cost and the installation space by sharing the existing auxiliary equipment. .

  FIG. 1 shows the configuration of the first embodiment after remodeling the two-shaft gas turbine.

  The two-shaft gas turbine is a compressor 1 that compresses atmospheric air to generate compressed air 11, a combustor 2 that generates combustion gas 13 by mixing and compressing compressed air 11 and fuel 12, and a high pressure that is rotationally driven by the combustion gas. The turbine 3 includes a low-pressure turbine 4 that is rotationally driven by exhaust gas 14 discharged from the high-pressure turbine 3, and a load device 5 that is directly connected to the low-pressure turbine 4. The rotor of the compressor 1 and the rotor of the high-pressure turbine 3 are connected by a first rotating shaft 21 to form a gas generator 0. The rotor of the low-pressure turbine 4 is connected to the load device 5 to be driven by the second rotary shaft 22, and forms a power turbine 00 that rotationally drives the low-pressure turbine 4 by the energy generated by the gas generator. The first rotating shaft 21 of the gas generator 0 is installed on the opposite side in the axial direction from the journal bearing 32 installed between the compressor 1 and the high-pressure turbine 3 and the high-pressure turbine 3 side with the compressor 1 as the center. The journal bearing 31 is rotatably supported. The second rotating shaft 22 of the power turbine 00 is rotatably supported by two journal bearings 33 and 34 installed between the low-pressure turbine 4 and the load device 5. Further, axial thrust is received by thrust bearings 41 and 42 between the upstream side of the compressor 1, the low-pressure turbine 4 and the load device 5.

  The sliding bearing is provided with a lubricating oil supply system 61 and a lubricating oil discharge system 62 for supplying and discharging lubricating oil to and from each bearing, and a lubricating oil tank 51 so that the lubricating oil can circulate in the lubricating oil supply and discharge system. Between the lubricating oil pump 52 and the auxiliary equipment of the lubricating oil filter 54. Further, a lubricating oil cooler 53 is formed to cool the thermal energy generated due to friction loss with the bearing, and cooling water is supplied by the lubricating oil cooling system 55. In this embodiment, the lubricating oil tank 51, the lubricating oil pump 52, the lubricating oil filter 54, the lubricating oil cooler 53, and the lubricating oil cooling system 55 utilize the existing auxiliary equipment of the single-shaft gas turbine. .

  Next, problems when remodeling the gas turbine will be described. For example, in a power plant having a single-shaft gas turbine, when replacing it with a single-shaft gas turbine of the same output band for the purpose of improving output and efficiency against the aging of the gas turbine, the number of bearings and the bearing size are Since it becomes equivalent, the amount of lubricating oil supplied to each bearing is also equivalent to the existing equipment. The lubricating system supplied to the bearings is also a general oil bath system (so-called oil dripping system), the lubricating oil tank 51, the lubricating oil pump 52, the lubricating oil filter 54, the lubricating oil cooler 53, the lubricating oil cooling. The auxiliary equipment such as the system 55 can use existing equipment. However, when replacing a single-shaft gas turbine with a twin-shaft gas turbine, the number of bearings increases, so the amount of lubricating oil supplied to each bearing decreases. When the amount of lubricating oil is reduced, the bearing metal surface temperature and the oil film temperature of the lubricating surface increase, and the bearing pad surface may be damaged. Further, there is a concern that the viscosity of the lubricating oil decreases due to a rise in the temperature of the bearing, and the unstable shaft vibration of the gas turbine increases due to a decrease in damping. Therefore, in order to secure the required amount of lubricating oil, it is necessary to modify auxiliary equipment such as a lubricating oil system such as a lubricating oil tank and a lubricating oil cooling water system, which has a long design period and installation process. , Leading to increased development costs. When the lubricating oil tank and the lubricating oil cooling water system are expanded in order to increase the amount of lubricating oil, the installation space may be different from that of the existing equipment, which may lead to a large remodeling. The high-pressure turbine 3 of the gas generator 0 is installed on the downstream side in the combustion gas flow direction of the two journal bearings 31 and 32 that support the first rotating shaft 21 that is a high-pressure turbine rotor. A so-called overhang structure is obtained. Therefore, the journal bearing 32 needs to support the rotation of the high-pressure turbine 3 that is heavy. In such an overhang structure of the high-pressure turbine rotor, a large radial load is applied to the journal bearing 32, so that the bearing surface pressure increases. In order to reduce the bearing surface pressure to an appropriate surface pressure, it is necessary to increase the bearing size. An increase in bearing size can cause an increase in the amount of lubricating oil. The journal bearing 32 is disposed in a high temperature region of the gas turbine between the compressor and the high pressure turbine. Therefore, the bearing is installed inside the casing of the gas turbine, and the lubricating oil supply / discharge system piping is introduced into the casing so that the lubricating oil can be supplied and discharged inside the casing. Therefore, it is important to secure the space for the piping of the lubricating oil supply / discharge system. The casing near the journal bearing 32 is provided with a combustor can in the circumferential direction, and the piping of the lubricating oil supply / discharge system is connected between the combustor transition pieces while avoiding the space of the outer cylinder of the combustor and the transition piece. Therefore, considering the space, it is desirable to make the pipe diameter as small as possible. An increase in the amount of lubricating oil and a reduction in the pipe diameter lead to an increase in the flow rate of lubricating oil supply / discharge, which may increase bearing loss and leak the lubricating oil. In particular, since the vicinity of the journal bearing 32 is in a high temperature range, avoidance of ignition due to leakage of lubricating oil is important for ensuring safety.

  Next, the characteristics of the bearing portion when remodeling from a single-shaft gas turbine to a twin-shaft gas turbine will be described. FIG. 2 schematically shows an example of a direct lubrication journal bearing according to the first embodiment as a cross-sectional view taken along a plane perpendicular to the rotor. FIG. 3 is a simplified perspective view of a direct lubrication type tilting pad bearing. The direct lubrication type bearing 32 has a configuration in which a slit 81 penetrating from the outer peripheral surface to the inner peripheral surface is provided in the tilting pad 71. Although not shown, the lubricating oil can be supplied to the slit on the outer peripheral surface of the tilting pad 71 from the outside of the bearing by the lubricating oil supply system 61. Further, the lubricating oil flowing from the slit 81 on the outer peripheral surface of the tilting pad 71 flows out to the inner peripheral surface, and the lubricating oil flows in the axial direction of the gas turbine rotor and is finally recovered by the lubricating oil discharge system 62. Returned to the lubricating oil tank 51. Lubricating by changing from an oil bath type in which the entire bearing is filled with oil to a direct lubrication type that enables rotation with the minimum amount of lubricating oil necessary to secure a liquid film between the pad surface and the rotor. It is possible to reduce the amount of oil. In particular, in the journal bearing 32, the bearing size is increased due to the overhang of the high-pressure turbine rotor, the amount of the lubricating oil is increased, and the flow rate of the lubricating oil supply / discharge is increased due to the reduction of the piping diameter of the lubricating oil supply / discharge system. In order to suppress it, the amount of lubricating oil can be reduced by adopting a direct lubrication type, and the flow rate of lubricating oil supply and discharge can be reduced to a predetermined flow rate. The improvement of directly applying the lubrication type to the journal bearing 32 has a great effect of reducing the total amount of lubricating oil.

  In order to improve the lubrication oil supply system of the sliding bearing from the oil bath system to the direct lubrication system in response to the modification from the single-shaft gas turbine to the 2-shaft gas turbine, the capacity of the existing lubricating oil tank 51 is improved. However, it is desirable to improve the journal bearing 32 positioned on the high pressure turbine side on the gas generator with priority. Furthermore, when there is no allowance for the amount of lubricating oil in the lubricating oil tank, it is desirable to improve the bearings 33, 34, and 31 in the order that the ambient temperature of the bearing is high. Since the lubricating oil also has an effect of lubricating the bearing surface and cooling the bearing metal, it is considered that improving the direct lubrication type from the bearing in the high temperature atmosphere has a great effect of reducing the total amount of the lubricating oil. Further, when there is a margin in the lubricating oil tank 51, it is not necessary to improve from the oil bath type. In the case of the direct lubrication type, as shown in FIG. Normally, the lubricating oil removes impurities in the lubricating oil through the lubricating oil filter 54. However, if there is a large scale impurity and the slit 81 is closed, the lubricating oil is supplied to the bearing surface. Otherwise, the bearing surface may be damaged. Therefore, when there is a margin in the amount of lubricating oil in the lubricating oil tank 51, it is not necessary to change directly to the lubrication type.

  The effect by having employ | adopted the direct lubrication type bearing of this Embodiment 1 is demonstrated. Reducing the amount of lubricating oil supplied to each bearing by increasing the number of bearings by remodeling from a single-shaft gas turbine to a twin-shaft gas turbine. Since a limited and appropriate amount of oil can be secured, the sliding characteristics are improved, and damage to the bearing pad surface due to increases in the bearing metal surface temperature and the oil film temperature on the lubricating surface can be suppressed. Further, it is possible to suppress an increase in unstable shaft vibration of the gas turbine due to the temperature rise of the bearing, and it is possible to maintain the reliability of the gas turbine and ensure the equipment life. Furthermore, since it is not necessary to modify auxiliary equipment such as a lubricating oil tank, lubricating oil pump, lubricating oil cooler, lubricating oil filter, and lubricating oil cooling water system, expansion of the installation space can be suppressed. If the auxiliary equipment can be diverted, the design and development period for modification can be shortened and the development cost can be reduced.

Furthermore, since the plant output and efficiency can be improved by remodeling from a single-shaft type to a two-shaft type gas turbine, it can also contribute to a reduction in fuel consumption and CO ₂ reduction effects. Moreover, the thermal efficiency of a gas turbine system can be improved by reducing the friction loss of a bearing.

  The present embodiment described above is a uniaxial gas turbine in which fuel is mixed with compressed air and burned, and the turbine is driven by high-temperature and high-pressure combustion gas. Lubricating oil device having a lubricating oil tank, a lubricating oil pump and a lubricating oil cooler, a lubricating oil supply system for supplying lubricating oil from the lubricating oil device to a plurality of bearings, and lubricating from the plurality of bearings to the lubricating oil device A gas turbine plant having a lubricating oil discharge system for recovering oil is modified. An existing single-shaft gas turbine, a compressor 1 that compresses air to generate compressed air, a combustor 2 that generates combustion gas by mixing and compressing compressed air and fuel compressed by the compressor 1, and combustion A two-shaft gas that has a high-pressure turbine 3 that is rotationally driven by the combustion gas generated in the vessel 2 and a low-pressure turbine 4 that is rotationally driven by the gas discharged from the high-pressure turbine 3 and is rotatably supported by a plurality of bearings Replace the turbine and supply the oil to the bearings of the two-shaft gas turbine using the one used in the existing single-shaft gas turbine in at least part of the lubricating oil equipment such as the lubricating oil tank and lubricating oil pump. It is configured to do.

  With this configuration, the time, labor, and space required when designing, manufacturing, and installing a new lubricating oil system can be saved, so a low-cost, space-saving and highly reliable gas turbine plant can be obtained. it can. In addition, since the single-shaft gas turbine is replaced with the twin-shaft gas turbine, the plant efficiency can be increased as compared with the existing one.

  In order to use what was used in the existing single-shaft gas turbine for at least part of the lubricating oil system, it is necessary for at least part of the bearings of the two-shaft gas turbine than for the existing single-shaft gas turbine. A bearing with a small amount of lubricating oil may be used. In this embodiment, a direct lubrication type bearing is used instead of the oil bath type bearing used in the existing single-shaft gas turbine as a bearing with a small amount of required lubricating oil. Lubricating oil is unnecessary for water bearings and magnetic bearings, which will be described later, and these can be said to be bearings that require a smaller amount of lubricating oil than directly lubricated bearings. By using such a bearing for the two-shaft gas turbine after replacement, the existing lubricating oil device for the single-shaft gas turbine can be used for the two-shaft gas turbine.

  Further, the two-shaft gas turbine of the present embodiment includes a first journal bearing 31 located on the upstream side of the compressor 1 and a second journal bearing 32 located between the compressor 1 and the high-pressure turbine 3. Have. Upstream means upstream in the flow direction of the working fluid in the axial direction. In this two-shaft gas turbine, it is desirable to use a bearing having a small amount of required lubricating oil such as a direct lubrication bearing as at least the second journal bearing 32. This is because the journal bearing 32 has a large bearing surface pressure and is installed in a high temperature range, and therefore requires a large amount of lubricating oil.

  The two-shaft gas turbine of the present embodiment further includes a third journal bearing 33 located downstream of the low-pressure turbine 4 and a fourth journal bearing 34 located downstream of the third journal bearing 33. Yes. The downstream means downstream in the flow direction of the working fluid in the axial direction. In this two-shaft gas turbine, the second journal bearing 32, the third journal bearing 33, the fourth journal bearing 34, and the first journal bearing 31 are required in the priority order according to the capacity of the lubricating oil tank 51. It is desirable to apply a bearing with a small amount of lubricating oil. That is, if the required amount of lubricating oil cannot be ensured only by changing the second journal bearing 32, the third journal bearing 33 is also a bearing having a small amount of necessary lubricating oil. 34 may also be a bearing with a small amount of lubricating oil. In this way, it is possible to consider changing bearings in descending order of the effect of reducing the total amount of lubricating oil, and efficient design becomes possible.

  FIG. 4 shows an example of a configuration after the two-shaft gas turbine is modified in the second embodiment.

  4 is different from the embodiment of FIG. 1 in that a pad of polyether ether ketone (PEEK) resin is introduced into the thrust bearings 41 and 42 of the gas generator 0 and the power turbine 00. Normally, white metal is used for bearing pads of industrial gas turbines, but pads using PEEK resin have better sliding characteristics than white metal. Therefore, the supply system and the discharge system of the lubricating oil supplied from the lubricating oil tank 51 to the thrust bearings 41 and 42 by the lubricating oil pump 52 are simplified (in FIG. 4, the simplification is achieved by omitting the lubricating oil supply / discharge system). Is shown.)

  Supply to other journal bearings by changing the specifications of the thrust bearing, which is a part of the gas turbine body, in response to an increase in the number of bearings accompanying the modification from a single-shaft gas turbine to a two-shaft gas turbine The amount of lubricating oil can be set appropriately, and the reliability of the bearing and the gas turbine can be ensured. In addition, since auxiliary equipment for lubricating oil can be used, it is possible to suppress an increase in installation space and an increase in cost. Furthermore, since the lubrication oil supply / discharge system to the bearing employing the PEEK resin can be simplified, the complexity of routing the piping is reduced. In addition, since PEEK resin generates little wear, maintenance work and maintenance costs can be reduced.

  In the embodiment of the present invention, the PEEK resin is used for the pad of the thrust bearing, but it can also be applied to other journal bearings. Moreover, you may utilize resin members other than PEEK resin.

  In FIG. 5, an example of the structure after the two-shaft type gas turbine remodeling in this Embodiment 3 is shown.

  5 is different from the embodiment of FIG. 1 in that the bearing lubrication of the journal bearing 31 and the thrust bearing 41 on the upstream side of the compressor of the gas generator 0 and the journal bearing 34 and the thrust bearing 42 on the load equipment side of the power turbine 00 are different. The material is water, that is, a water bearing is applied to the bearing.

  Next, the supply and discharge system of the lubricating water to the water bearing will be described. Lubricating water is supplied from an external lubricating water tank 56 to the journal bearing 31 and the thrust bearing 41 on the upstream side of the compressor and the journal bearing 34 and the thrust bearing 42 on the power turbine side via the lubricating water supply system 63 by the lubricating water pump 57. Is done. The supplied lubricating water absorbs frictional heat while serving as a lubricant in the vicinity of the bearing, and is collected into the lubricating water tank 56 through the lubricating water discharge system 64. Or it may be drained to the outside. In this embodiment, normal temperature water is used as the lubricating water, and there is a possibility that foreign matter in the lubricating water tank or the piping system may be mixed in the lubricating water, in order to avoid damage to the bearing pad surface. It is desirable to remove foreign matter through a lubricating water filter before supplying it to the bearing.

  In addition, when water is applied to the lubricant, it is desirable to avoid a high ambient temperature around the bearing. If a water bearing is applied to the journal bearing between the compressor and the high pressure turbine, the journal bearing is exposed to a high temperature of about 200 ° C. to 600 ° C. Therefore, the lubricating water supplied to the bearing is locally saturated. Possible to exceed 100 ° C. If part of the lubricating water inside the bearing exceeds the saturation temperature, bubbles may be generated as the lubricating water tries to evaporate. When air bubbles are generated on the bearing surface, the lubricating water liquid film between the bearing pad surface and the rotor is cut to increase friction loss. Further, the pad surface and the metal surface of the rotor may be in direct contact with each other, which may damage the bearing pad and may cause unstable vibration of the gas turbine. Thus, when the temperature of the lubricating water is equal to or higher than the saturation temperature, the reliability of the bearing portion is lowered.

  In contrast to the increase in the number of bearings accompanying the modification from a single-shaft gas turbine to a two-shaft gas turbine, the amount of lubricating oil supplied to other bearings can be reduced by applying water bearings to bearings in a low-temperature atmosphere. It is possible to set appropriately, and the reliability of a bearing and a gas turbine can be ensured. Also, since auxiliary equipment for lubricating oil can be used, it is possible to suppress an increase in installation space and an increase in cost. The piping of the lubrication oil supply / drainage system and the lubrication water supply / exhaust system may be complicated, but water is used instead of oil for the lubricant, so it will ignite even if lubrication water leaks from the bearings and piping. There is no danger of doing. Therefore, safety can be maintained.

  In the embodiment of the present invention, the water bearing is applied to the bearing on the upstream side of the compressor and the bearing on the load equipment side of the power turbine. However, the present invention is not limited to this. Is also applicable.

  FIG. 6 shows an example of a configuration after the two-shaft gas turbine is modified in the fourth embodiment.

  6 is different from the embodiment in FIG. 1 in that magnetic bearings are applied to the journal bearings 33 and 34 and the thrust bearing 42 on the power turbine side. A magnetic bearing is a bearing that uses an electromagnet as a bearing and floats and supports the rotor by electromagnetic force generated by the electromagnet. When the power turbine 00 rotates at a high speed, the rotor position is detected by a displacement sensor, and an electromagnetic force necessary for the electromagnet is induced to control the rotor position. Therefore, no lubricant is required between the bearing surface and the rotor, and there is no need to supply lubricating oil to the power turbine bearing, and there is no need to provide a lubricating oil supply / discharge system.

  In contrast to the increase in the number of bearings accompanying the modification from a single-shaft gas turbine to a two-shaft gas turbine, magnetic bearings are used instead of plain bearings, so the amount of lubricating oil supplied to other plain bearings can be reduced. It becomes possible to set appropriately, and the reliability of a bearing and a gas turbine can be ensured. In addition, since the piping of the lubricating oil supply / discharge system is not required, the equipment can be made compact and maintenance work can be reduced. Further, unlike the sliding bearing, the magnetic bearing has no lubricant between the bearing pad surface and the rotor, so that no friction loss occurs. Therefore, the wear and noise of the bearing are small and high-speed rotation is possible, and a long life can be expected. Since the friction loss of the bearing can be reduced, it is possible to improve the efficiency and output of the gas turbine system.

  In the embodiment of the present invention, the magnetic bearing is applied to the bearing of the power turbine. However, the present invention is not limited to this and can be applied to other bearing configurations. However, since the heat resistance temperature of a magnetic bearing is generally about 150 ° C., when the temperature limit value is exceeded by using a magnetic bearing in a high temperature portion, the bearing portion may be cooled and applied at a temperature limit value or less. desirable.

  FIG. 7 shows an example of a configuration after remodeling the two-shaft gas turbine in the fifth embodiment.

  7 differs from the embodiment of FIG. 1 in that a separate lubricating oil tank 58, lubricating oil pump 59, lubricating oil amount adjusting mechanism 60, and lubricating oil supply / discharge system are installed. In an ordinary industrial gas turbine, the temperature of the bearing metal is measured, and the flow rate is adjusted by an orifice or the like installed in the lubricating oil supply pipe so as to be equal to or lower than a predetermined temperature. In this embodiment, the temperature of each bearing metal is monitored, and when it exceeds a predetermined temperature, a lubricating oil amount adjusting mechanism 60 such as a throttle valve installed downstream from the separately installed lubricating oil tank 58 and the lubricating oil pump 59. Is used to introduce the lubricating oil into the lubricating oil supply system 61 so that the bearing metal temperature is controlled to a predetermined temperature or lower. The lubricating oil supplied to the bearing lubricates and cools the bearing pad surface, and is collected in the existing lubricating oil tank 51 through the lubricating oil discharge system 62. When the lubricating oil in the existing lubricating oil tank 51 reaches a certain amount or more, the lubricating oil passes through the lubricating oil discharge system that communicates with the existing lubricating oil tank 51 and the separate lubricating oil tank 58, and the lubricating oil becomes a separate lubricating oil. It is introduced into the tank 58.

  This makes it possible to adjust the amount of lubricating oil supplied to the bearing while monitoring the bearing metal temperature, as the number of bearings increases as a result of remodeling from the single-shaft gas turbine to the twin-shaft gas turbine. Therefore, the reliability of the bearing and the gas turbine can be ensured.

  In the above-described embodiment, the configuration is such that all the lubricating oil supplied to each bearing is adjusted by one separate lubricating oil tank and the lubricating oil amount adjusting mechanism, but is not limited thereto. For example, a mechanism capable of individually adjusting the lubricating oil amount while monitoring each bearing metal temperature by providing a lubricating oil amount adjusting mechanism in the lubricating oil supply system supplied to each bearing is also possible.

  According to each embodiment described above, in a remodeling method for replacing an existing single-shaft gas turbine with a twin-shaft gas turbine, even if the amount of lubricating oil supplied to each bearing device is reduced due to an increase in the number of bearings. The damage of the bearing surface and the unstable vibration of the gas turbine rotor due to the temperature rise of the bearing can be suppressed, the reliability of the gas turbine can be improved, and the equipment life can be ensured.

  Further, the plant output and efficiency can be improved by remodeling the gas turbine from the single-shaft type to the two-shaft type. Furthermore, since the existing auxiliary equipment such as a lubricating oil device, a lubricating oil tank, a pump, and a cooling system for the lubricating oil can be shared, the equipment cost can be reduced. In addition, since the auxiliary equipment can be shared, the design period and production period required for remodeling can be greatly reduced.

  In addition to being used for power generation as a high-efficiency gas turbine, it can also be applied as a cogeneration system that can supply both heat and power.

DESCRIPTION OF SYMBOLS 0 Gas generator 00 Power turbine 1 Compressor 2 Combustor 3 High pressure turbine 4 Low pressure turbine 5 Load apparatus 21 1st rotating shaft 22 2nd rotating shaft 31-34 Bearing 41,42 Thrust bearing 51 Lubricating oil tank 52 Lubricating oil pump 53 Lubricating oil cooler 54 Lubricating oil filter 55 Lubricating oil cooling system 56 Lubricating water tank 57 Lubricating water pump 58 Separate lubricating oil tank 59 Separate lubricating oil pump 60 Lubricating oil amount adjusting mechanism 61 Lubricating oil supply system 62 Lubricating oil Discharge system 71 Tilting pad 81 Slit

Claims (7)

A single-shaft gas turbine in which fuel is mixed with compressed air and burned, and a turbine is driven by high-temperature and high-pressure combustion gas, and a rotary shaft rotatably supported by a plurality of bearings;
A lubricating oil device having a lubricating oil tank, a lubricating oil pump, and a lubricating oil cooler; a lubricating oil supply system for supplying lubricating oil from the lubricating oil device to the plurality of bearings; and the lubricating oil device from the plurality of bearings In a method for remodeling a gas turbine plant having a lubricating oil discharge system for collecting lubricating oil,
The single-shaft gas turbine,
A compressor that generates compressed air by compressing air, a combustor that generates combustion gas by mixing and compressing compressed air and fuel compressed by the compressor, and rotationally driven by the combustion gas generated by the combustor A high-pressure turbine and a low-pressure turbine that is rotationally driven by gas discharged from the high-pressure turbine, and is replaced with a two-shaft gas turbine that is rotatably supported by a plurality of bearings;
A method for remodeling a gas turbine plant, characterized in that at least part of the lubricating oil device is used to supply lubricating oil to a bearing of the two-shaft gas turbine. The gas turbine plant remodeling method according to claim 1,
A method for remodeling a gas turbine plant, wherein a bearing having a smaller amount of lubricating oil than that of the single-shaft gas turbine is used as at least a part of the bearing of the double-shaft gas turbine. The method for remodeling a gas turbine plant according to claim 1 or 2,
The single-shaft gas turbine has an oil bath bearing,
A method for remodeling a gas turbine plant, wherein at least one oil bath type bearing of the one-shaft gas turbine is changed to a direct lubrication type bearing in the two-shaft gas turbine. In the modification method of the gas turbine plant in any one of Claims 1-3,
A method for remodeling a gas turbine system, wherein at least one of a water bearing and a magnetic bearing is used for at least a part of a bearing of the two-shaft gas turbine. In the gas turbine plant remodeling method according to any one of claims 1-4,
A method for remodeling a gas turbine plant, wherein a bearing member constituting the bearing is made of resin. In the remodeling method of the gas turbine plant in any one of Claims 2-5,
The two-shaft gas turbine has a first journal bearing located on the upstream side of the compressor, and a second journal bearing located between the compressor and the high-pressure turbine,
A method for remodeling a gas turbine plant, wherein at least the second journal bearing is a bearing that requires less lubricating oil than the single-shaft gas turbine. The gas turbine plant remodeling method according to claim 6,
The two-shaft gas turbine has a third journal bearing located downstream of the high-pressure turbine, and a fourth journal bearing located downstream of the third journal bearing,
Depending on the capacity of the lubricating oil tank, the second journal bearing, the third journal bearing, the fourth journal bearing, and the first journal bearing need to be prioritized over the single-shaft gas turbine. A gas turbine plant remodeling method characterized by using a bearing with a small amount of lubricating oil.

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