Cold energy power generation device and cold energy power generation system

Abstract

To provide a cold power generating device capable of suppressing deterioration of generator performance by reducing windage loss (loss) in a thrust bearing.SOLUTION: Provided is a cold power generating device comprising a thrust bearing device arranged on one side in an axial direction of a rotor shaft from a first journal bearing device on an inner peripheral side of an inner casing. In the cold power generating device, a gap in a radial direction connected to a heat medium flow path is defined between the other side end surface, which is an end surface on the other side of the inner casing, and a disk part, and the inner casing forms at least one pressure equalization flow path which communicates a first space on the one side from the first journal bearing device inside the inner casing with the gap in the radial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a cold energy power generation device and a cold energy power generation system. [Background technology]

[0002] Liquefied gas (for example, liquefied natural gas) is liquefied for the purpose of transportation and storage, and when it is supplied to destinations such as city gas or thermal power plants, it is heated and vaporized using a heat medium such as seawater. When vaporizing liquefied gas, there is a type of cold energy generation in which the cold energy is recovered as electricity rather than being discarded into seawater.

[0003] ORC (Organic Rankine Cycle) is a known cryogenic power generation cycle that uses liquefied natural gas. ORC is a cycle process in which a low-temperature working fluid with a boiling point lower than that of water circulating in a closed loop is cooled and condensed with liquefied natural gas in a condenser, then pressurized by a pump, heated and evaporated in an evaporator using seawater or other heat sources, and the resulting steam is introduced into a cryogenic power generation turbine to generate power.

[0004] Patent Document 1 discloses a cold energy power generation device in which a turbine and a generator are coaxially arranged in the same casing in order to reduce the size of the device. In this cold energy power generation device, the generator is arranged in the center of the shaft, and the turbine and thrust bearing are arranged on one side of the generator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Utility Model No. 210660229 Summary of the Invention [Problem to be solved by the invention]

[0006] In the conventional configuration shown in Patent Document 1, the thrust bearing is located upstream of the generator inside the casing, and the location where the thrust bearing is located is subject to high pressure. As a result, windage loss occurs due to rotation in the thrust bearing in the cold energy power generation turbine, which may result in a decrease in generator performance.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a cold energy power generation device that can suppress a decline in generator performance by reducing windage loss (loss) in thrust bearings. [Means for solving the problem]

[0008] In order to achieve the above object, the cold energy power generation device according to the present disclosure is a cold energy power generation device provided in a heat medium circulation line configured to circulate a heat medium for heating liquefied gas, and includes a generator including a rotor shaft, a motor rotor supported on an outer peripheral surface of the rotor shaft, and a motor stator arranged opposite to the motor rotor, an inner casing that houses the generator, an outer casing that is arranged on the outer peripheral side of the inner casing and defines a heat medium flow path between itself and the inner casing, a first stage turbine device that is arranged in the heat medium flow path and is arranged on one side of the generator in the axial direction of the rotor shaft, a second stage turbine device that is arranged in the heat medium flow path and is arranged on the other side of the generator in the axial direction of the rotor shaft, and a the second stage turbine device includes a journal bearing device arranged on the other side of the generator, and a thrust bearing device arranged on the one side of the journal bearing device on an inner peripheral surface of the inner casing, the second stage turbine device includes second stage stator vanes and second stage rotor blades provided on the other side of the second stage stator vanes, the rotor shaft includes a disk portion extending radially and supporting the second stage rotor blades of the second stage turbine device, a radial gap connected to the heat medium flow path on the other side of the second stage stator vanes is defined between the other end face that is the end face on the other side of the inner casing and the disk portion, and at least one pressure equalizing flow path is formed in the inner casing, communicating the radial gap with a first space inside the inner casing on the one side of the journal bearing device. [Effects of the Invention]

[0009] According to the cold energy power generation device disclosed herein, the pressure inside the inner casing at the position where the thrust bearing device is located can be reduced, and by reducing windage loss caused by the thrust bearing device, a decrease in generator performance can be suppressed. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a schematic diagram illustrating an overall configuration of a cold energy power generation system including a cold energy power generation device according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic cross-sectional view of a cryogenic power generating device according to an embodiment of the present disclosure. [Figure 3] 2 is an enlarged cross-sectional view of the second stage turbine and its surroundings in a cold energy power generation device according to an embodiment of the present disclosure. FIG. [Figure 4] FIG. 3 is a schematic view of the AA cross section of the cryogenic power generation device shown in FIG. [Figure 5] 3 is a schematic view of the cross section BB of the cryogenic power generation device shown in FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," or "have" one element are not exclusive expressions that exclude the presence of other elements. Note that the same components will be denoted by the same reference numerals and the description thereof will be omitted.

[0012] (Cold energy power generation system) FIG. 1 is a schematic diagram illustrating the overall configuration of a cold energy power generation system including a cold energy power generation device according to an embodiment of the present disclosure.

[0013] The cryogenic power generation system 100 according to one embodiment of this invention is a cryogenic power generation system 100 for recovering cryogenic energy contained in liquefied gas as electric power via a heat medium for heating the liquefied gas. The cold energy power generation system 100 is not particularly limited, but is installed, for example, on a waterborne floating structure 10A or a land-based liquefied gas base 10B, which will be described below.

[0014] The water floating structure 10A is a structure that can float on water. The water floating structure 10A has a propulsion device configured to drive a propeller or other thruster, and includes ships that can move independently by driving the propulsion device, as well as floating bodies that do not have a propulsion device. The water floating structure 10A stores liquefied gas in liquid form, which is heated and vaporized by seawater or the like, and then flows into an engine (not shown) to generate propulsion power. When the liquefied gas is vaporized, the cold energy generated by the cold energy power generation system 100 is not discarded into seawater, but is instead recovered as electricity by the cold energy power generation device 1 described below.

[0015] The land-based liquefied gas terminal 10B receives and stores liquefied gas transported by LNG carriers. When the liquefied gas is supplied to a liquefied gas supply destination such as a city gas or thermal power plant, the liquefied gas is heated using seawater or the like to return to gas. When the liquefied gas is vaporized, the cold energy generated by the cold power generation system 100 is not dumped into seawater, but is instead recovered as electricity by the cold power generation device 1, which will be described later.

[0016] In the following embodiment, a case will be described in which the cryogenic power generation system 100 of the present disclosure is installed on a ship 10 that uses liquefied gas as fuel, among the above-mentioned water floating structures 10A.

[0017] As shown in Fig. 1, the cold energy power generation system 100 includes a cold energy power generation device 1, a liquefied gas supply line 2, a condenser 3, a heating fluid supply line 4, a cold energy pump 5, an evaporator 7, and a heat medium circulation line 9. The cold energy power generation device 1, the condenser 3, the cold energy pump 5, and the evaporator 7 are all connected by the heat medium circulation line 9. The liquefied gas supply line 2 is connected to the condenser 3. The heating fluid supply line 4 is connected to the evaporator 7. The heat medium circulation line 9, the liquefied gas supply line 2, and the heating fluid supply line 4 each include a flow path, such as a pipe, through which a fluid flows. The cold energy power generation system 100 is configured to be driven by the heat medium circulating through the heat medium circulation line 9 while changing its state between liquid and gas.

[0018] The heat medium circulation line 9 is configured to circulate a heat medium having a lower freezing point than water. In the following, liquefied natural gas (LNG) is used as a specific example of a liquefied gas, and propane is used as a specific example of a heat medium flowing through the heat medium circulation line 9. However, the present disclosure is also applicable to liquefied gases other than liquefied natural gas (such as liquefied hydrogen), and is also applicable to cases where a heat medium other than propane, such as R1234yf or R1234ze, is used as a heat medium flowing through the heat medium circulation line 9.

[0019] The condenser 3 is configured to condense the working fluid (heat medium) by heat exchange between the heat medium and the liquefied gas. Inside the condenser 3, there are provided a heating-side pipe connected to the heat medium circulation line 9 and into which the heat medium circulating through the heat medium circulation line 9 flows, and a heated-side pipe connected to the liquefied gas supply line 2 and into which the liquefied gas flowing through the liquefied gas supply line 2 flows. The condenser 3 is configured so that heat exchange occurs between the heat medium flowing through the heating-side pipe and the liquefied gas flowing through the heated-side pipe. In the condenser 3, the heat medium is cooled and condensed by heat exchange, and the liquefied gas is heated.

[0020] The liquefied gas supply line 2 upstream of the condenser 3 is connected to a liquefied gas pump 22, and the further upstream side of the liquefied gas pump 22 is connected to a liquefied gas storage device 21. By driving the liquefied gas pump 22, the liquefied gas stored in the liquefied gas storage device 21 is sent to the liquefied gas supply line 2, flows through the liquefied gas supply line 2 from the upstream side to the downstream side, and is supplied to the condenser 3. The liquefied gas vaporized by heat exchange inside the condenser 3 flows through the heated side pipe, and then flows through the liquefied gas supply line 2 again, and is supplied as fuel to the engine (not shown) of the ship 10 installed downstream of the condenser 3.

[0021] The cold heat pump 5 is configured to increase the pressure of the heat medium supplied from the condenser 3. When the cold heat pump 5 connected to the heat medium circulation line 9 is driven, the heat medium circulates through the heat medium circulation line 9. The heat medium flows from the condenser 3 to the cold heat pump 5, from the cold heat pump 5 to the evaporator 7, from the evaporator 7 to the cold power generation device 1, and from the cold power generation device 1 to the condenser 3.

[0022] The cold / heat pump 5 may be of any type as long as it can pressurize the heat medium. For example, a turbo pump (such as a centrifugal pump, mixed flow pump, or axial flow pump), a positive displacement pump (such as a reciprocating pump or rotary pump), or a special pump (such as a submersible motor pump) may be used, and the type may be appropriately selected according to the embodiment.

[0023] The evaporator 7 is configured to evaporate the heat medium by heat exchange between the heat medium pressurized by the cold heat pump 5 and a heating fluid introduced from outside the cold power generation system 100. Inside the evaporator 7, there are provided a heat medium heated-side pipe line into which the heat medium pressurized by the cold heat pump 5 flows and which is connected to the heat medium circulation line 9, and a heat medium heating-side pipe line connected to the heating fluid supply line 4 and into which the heating fluid introduced from outside the cold power generation system 100 flows. The heat medium flowing in the heat medium heated-side pipe line and the heating fluid flowing in the heat medium heating-side pipe line are configured to exchange heat. In the evaporator 7, the heat medium is heated and evaporated by heat exchange, and the heating fluid is cooled.

[0024] The heating fluid supply line 4 upstream of the evaporator 7 is connected to a heating fluid pump 42. The heating fluid supply line 4 further upstream of the heating fluid pump 42 is connected to a heating fluid supply source so that heating fluid is introduced from outside the cold power generation system 100. By driving the heating fluid pump 42, the heating fluid is sent from the heating fluid supply source to the heating fluid supply line 4, flows through the heating fluid supply line 4 from upstream to downstream, and is supplied to the evaporator 7. The heating fluid is cooled by heat exchange inside the evaporator 7, flows through the heat medium heating side pipe, and then flows through the heating fluid supply line 4 again, and is discharged to the outside of the cold power generation system 100.

[0025] The above-mentioned "heating fluid" may be any fluid that heats the heat medium circulating through the heat medium circulation line 9 as a heat medium in the evaporator 7, and may be steam, hot water, seawater, engine cooling water, or water at room temperature. When the cold energy power generation system 100 is installed on a ship 10, the heating fluid can preferably be water that is easily available on the ship 10 (for example, outside water such as seawater, or engine cooling water that cools the engine of the ship 10).

[0026] The cold energy power generation device 1 is configured to be driven by a gaseous heat medium generated in an evaporator 7. The cold energy power generation device 1 also has a generator 8. The generator 8 is driven by a rotor shaft 11 of the cold energy power generation device 1, which will be described later, being rotated by the gaseous heat medium produced in the evaporator 7. The gaseous heat medium that has driven the cold energy power generation device 1 flows through a heat medium circulation line 9 toward the condenser 3, which is installed downstream of the cold energy power generation device 1, as described above.

[0027] (Configuration of cold energy power generation equipment) Fig. 2 is a schematic cross-sectional view of a cold energy power generation device 1 according to an embodiment of the present disclosure. Fig. 3 is an enlarged cross-sectional view of the second stage turbine device 24 and its surroundings of the cold energy power generation device 1 according to an embodiment of the present disclosure. Fig. 4 is a schematic view of the AA cross section of the cold energy power generation device shown in Fig. 2. Hereinafter, the upstream side in the flow direction of the heat medium in the cold energy power generation device 1 may be simply referred to as the upstream side, and the downstream side in the flow direction of the heat medium in the cold energy power generation device 1 may be simply referred to as the downstream side. Furthermore, the radial direction of the cold energy power generation device 1 may be simply referred to as the radial direction, and the circumferential direction of the cold energy power generation device 1 may be simply referred to as the circumferential direction. Furthermore, the direction along the axis CA of the cold energy generator 1 may be simply referred to as the axial direction.

[0028] As shown in Figure 2, the cold energy power generation device 1 in some embodiments includes a rotor shaft 11, a generator 8, a casing 6, a first stage turbine device 23, a second stage turbine device 24, a first journal bearing device 103, a second journal bearing device 104, and a thrust bearing device 102.

[0029] (rotor shaft) In the illustrated embodiment, the rotor shaft 11 includes a shaft portion 111 having a longitudinal direction along the axis CA of the cold energy power generation device 1, a one-side disk portion 113A extending along the radial direction of the rotor shaft 11 on one side (upstream side) of the shaft portion 111 and supporting a first-stage rotor blade 23B described later, and a other-side disk portion 113B extending along the radial direction of the rotor shaft 11 on the other side (downstream side) of the shaft portion 111 and supporting a second-stage rotor blade 24B described later. The axis of the rotor shaft 11 coincides with the axis CA of the cold energy power generation device 1 and the axis of the casing 6. In addition, in the embodiment shown in Figure 2, the axis of the rotor shaft 11 is aligned with the horizontal direction, and the center of one end of the shaft portion 111 and the center of the other end of the shaft portion 111 are positioned at the same height level in the vertical direction.

[0030] One-side disk portion 113A and other-side disk 113B are fixed to shaft portion 111 with nuts, and protrude radially outward in a disk shape from the outer surface of shaft portion 111. The portions of shaft portion 111 to which one-side disk portion 113A and other-side disk 113B are attached are formed with a smaller diameter than the other portions.

[0031] (Generator) The generator 8 is configured to include a motor rotor 81 supported on the outer peripheral surface of the rotor shaft 11 and a motor stator 82 disposed opposite the motor rotor 81. In the illustrated embodiment, the motor rotor 81 is formed integrally with the outer circumferential surface of the rotor shaft 11, and the two have an integral structure. However, the motor rotor 81 and the rotor shaft 11 may be formed separately, and the motor rotor 81 may be supported on the outer circumferential surface of the rotor shaft. The motor stator 82 is supported on the inner circumferential surface 611 of the inner casing 61, which will be described later, and is positioned radially outward of the motor rotor 81.

[0032] (Casing) The casing 6 is composed of an inner casing 61 that houses the rotor shaft 11 and an outer casing 62 that is arranged on the outer periphery of the inner casing 61 and houses the inner casing 61 .

[0033] The inner casing 61 has a longitudinal direction along the axial direction of the cold energy power generation device 1, and is disposed between the first stage rotor blades 23B and the second stage rotor blades 24B in the axial direction of the cold energy power generation device 1. A space 610 is formed inside the inner casing 61, and houses the shaft portion 111 and the generator 8 (in the illustrated example, the motor rotor 81 and the motor stator 82).

[0034] Furthermore, a heat transfer medium flow path 63 is defined between the inner casing 61 and the outer casing 62. The heat transfer medium flow path 63 is defined between an outer peripheral surface 612 of the inner casing 61 and an inner peripheral surface 621 of the outer casing 62, and is configured to extend along the axial direction of the rotor shaft 11 from upstream of the first-stage stator vanes 23A to downstream of the second-stage rotor blades 24B. In the illustrated embodiment, the heat medium flow path 63 has a longitudinal direction along the axial direction of the cold energy power generation device 1 and has an annular cross section surrounding the periphery of the inner casing 61. The heat medium flow path 63 is configured to guide the heat medium from one side to the other between the outer casing 62 and the inner casing 61.

[0035] In the illustrated embodiment, a one-side cover 66A is arranged on one side (upstream side) of the inner casing 61, and a other-side cover 66B is arranged on the other side (downstream side). The one-side cover 66A is arranged on one side of the inner casing main body 61A so as to cover one end of the shaft portion 111 on one side in the axial direction of the first-stage rotor blades 23B. The other-side cover 66B is arranged on the other side of the inner casing main body 61A so as to cover the other end of the shaft portion 111 on the other side in the axial direction of the second-stage rotor blades 24B.

[0036] The heat medium flow path 63 extends to one side of the inner casing 61 by a space defined between the one-side cover 66A and the outer casing 62. Similarly, the heat medium flow path 63 extends to the other side of the inner casing 61 by a space defined between the other-side cover 66B and the outer casing 62.

[0037] Furthermore, a one-side inlet passage 64A is formed on one side of the heat medium flow path 63 to introduce the heat medium from one side along the axial direction into the heat medium flow path 63. The one-side inlet passage 64A is defined by the inner surface of an inlet casing 65A connected to one side of the outer casing 62, on one axial side of the inner casing 61. Further, a second discharge passage 64B is formed on the other side of the heat medium flow passage 63 to discharge the heat medium in the axial direction from the heat medium flow passage 63 to the other side. The second discharge passage 64B is defined by the inner surface of an outlet casing 65B connected to the other side of the outer casing 62, on the other axial side of the inner casing 61.

[0038] The heat medium introduced into the heat medium flow path 63 from the one-side introduction path 64A passes through the first-stage stator vanes 23A, and then acts on the first-stage rotor blades 23B to apply a rotational force to the rotor shaft 11, thereby driving the first-stage turbine device 23. The heat medium that has passed through the first-stage rotor blades 23B exchanges heat with heat generated in the generator 8 (motor rotor 81, motor stator 82) housed in the space 610 formed inside the inner casing 61 while flowing through the heat medium flow path 63. In other words, the heat generated in the generator 8 is absorbed by the heat medium flowing through the heat medium flow path 63. As a result, the generator 8 is cooled, and the heat medium flowing through the heat medium flow path 63 is heated.

[0039] The heated heat medium passes through the second-stage stator blades 24A and then acts on the second-stage rotor blades 24B to apply a rotational force to the rotor shaft 11, thereby driving the second-stage turbine device 24. In other words, the heat medium heated by heat exchange with the generator 8 in the heat medium flow path 63 flows into the second-stage turbine device 24, and this heated heat medium drives the second-stage turbine device 24. The heat medium that has flowed through the second-stage turbine device 24 is discharged from the heat medium flow path 63 to the other-side discharge path 64B and flows out of the cold energy power generation device 1.

[0040] (First stage turbine unit) The first-stage turbine device 23 is disposed in the heat medium flow path 63. The first-stage turbine device 23 is configured to include a first-stage rotor blade 23B provided on one side of the rotor shaft 11 relative to the motor rotor 81, and a first-stage stator blade 23A supported by the inner circumferential surface 621 of the outer casing 62 or the inner casing 61 on one side of the rotor shaft 11 relative to the first-stage rotor blade 23B. In the illustrated embodiment, the first-stage rotor blades 23B are attached to the outer peripheral surface of the one-side disk portion 113A described above at intervals in the circumferential direction. The first-stage stator vanes 23A are supported by the inner peripheral surface 621 of the outer casing 62 and are provided at intervals in the circumferential direction on the inner peripheral surface 621. In other embodiments, the first-stage stator vanes 23A may be supported by the inner casing 61 and provided at intervals in the circumferential direction, or may be supported by both the inner peripheral surface 621 of the outer casing 62 and the inner casing 61.

[0041] (Second stage turbine unit) The second-stage turbine device 24 is disposed in the heat medium flow path 63. The second-stage turbine device 24 is configured to include second-stage stator vanes 24A supported on the inner circumferential surface 621 of the outer casing 62 or the outer circumferential surface 612 of the inner casing 61 on the other side of the rotor shaft 11 from the motor rotor 81, and second-stage rotor blades 24B provided on the other side of the rotor shaft 11 from the second-stage stator vanes 24A. In the illustrated embodiment, the second-stage rotor blades 24B are attached to the outer peripheral surface of the above-mentioned other-side disk portion 113B at intervals in the circumferential direction. The second-stage stator vanes 24A are supported by the inner peripheral surface 621 of the outer casing 62 and are provided on the inner peripheral surface 621 at intervals in the circumferential direction. In other embodiments, the second-stage stator vanes 24A may be supported by the outer peripheral surface 612 of the inner casing 61 and be provided on the outer peripheral surface 612 at intervals in the circumferential direction, or may be supported by both the inner peripheral surface 621 of the outer casing 62 and the outer peripheral surface 612 of the inner casing 61.

[0042] (First journal bearing device) The first journal bearing device 103 is disposed inside the inner casing 61 on the other side of the generator 8, and includes a main bearing 103A and an auxiliary bearing 103B. In the illustrated embodiment, a main bearing 103A and an auxiliary bearing 103B that rotatably support the rotor shaft 11 are housed in a space 610 formed inside the inner casing 61. The main bearing 103A is disposed on the other side of the motor rotor 81. The auxiliary bearing 103B is disposed further on the other side than the main bearing 103A. The first journal bearing device 103 may include only the main bearing 103A.

[0043] (Second journal bearing device) The second journal bearing device 104 is disposed inside the inner casing 61 on one side of the generator 8, and includes a main bearing 104A and an auxiliary bearing 104B. In the illustrated embodiment, a main bearing 104A and an auxiliary bearing 104B that rotatably support the rotor shaft 11 are housed in a space 610 formed inside the inner casing 61. The main bearing 104A is arranged on one side of the motor rotor 81. The auxiliary bearing 104B is arranged further on one side of the main bearing 104A. Note that the second journal bearing device 104 may include only the main bearing 104A. Furthermore, in the case of a cold energy power generation plant 1 that is configured so that the rotor shaft 11 can be rotatably supported by only the first journal bearing device 103, the second journal bearing device 104 may not be provided.

[0044] In one embodiment, the main bearings 103A and 104A may be magnetic bearings, and the auxiliary bearings 103B and 104B may be ball bearings. When the cold energy power generation plant 1 stops or trips due to a problem, these auxiliary bearings 103B and 104B support the rotor shaft 11, thereby preventing contact between the main bearings 103A and 104A and the rotor shaft 11.

[0045] (Thrust bearing device) The thrust bearing device 102 is disposed inside the inner casing 61 on one side of the first journal bearing device 103. The thrust bearing device 102 is configured to include a one-side thrust bearing 102A and an other-side thrust bearing 102B disposed in a space 610 formed inside the inner casing 61, and receives the axial load (thrust force) of the rotor shaft 11. 2 and 3 , in the illustrated embodiment, the rotor shaft 11 further includes a thrust collar 112 extending radially inside the inner casing 61 on one side of the first journal bearing device 103 and on the other side of the generator 8. The one-side thrust bearing 102A abuts against one side surface 112A, which is one side surface of the thrust collar 112 provided on the rotor shaft 11. The other-side thrust bearing 102B abuts against another side surface 112B, which is the other side surface of the thrust collar 112. In another embodiment, the thrust bearing device 102 and the thrust collar 112 may be disposed inside the inner casing 61 on one side of the generator 8 . The thrust bearing device 102 (one-side thrust bearing 102A and the other-side thrust bearing 102B) may be configured by a magnetic bearing.

[0046] (radial clearance) As shown in FIG. 3, a radial gap 241 connected to the heat medium flow path 63 downstream of the second stage stator vane 24A is defined between the other end face 613, which is the other end face of the inner casing 61, and the other side disk portion 113B. In the illustrated embodiment, the radial gap 241 is connected between the second-stage stator vane 24A and the second-stage rotor blade 24B in the heat transfer medium flow path 63, and has an annular cross section surrounding the rotor shaft 11. The radial gap 241 has a uniform width in the axial direction and extends along the radial direction.

[0047] (equal pressure flow path) In some embodiments of the cold-energy power generation device 1, as shown in Figure 3, the inner casing 61 has at least one pressure equalizing flow path 40 formed therein to connect the first space 614 on one side of the first journal bearing device 103 inside the inner casing 61 with the radial gap 241. 3, the pressure equalizing passage 40 includes a first-space-side opening 40A that opens into the first space 614, a radial gap-side opening 40B that opens into the other-side end face 613, a radial passage 401 that extends radially from the first-space-side opening 40A, an axial passage 402 that connects to the radial passage 401 and extends in the axial direction of the rotor shaft 11, and a other-side passage 403 that connects the axial passage 402 and the radial gap-side opening 40B. The other-side passage 403 extends such that the distance from the axis of the rotor shaft 11 increases as it moves from the radial gap-side opening 40B to one side.

[0048] The first space-side opening 40A is located radially outward from the radially inner end 102B1 of the other-side thrust bearing 102B, which is a stationary member. Therefore, the heat transfer medium that flows from the upstream to the downstream of the thrust bearing device 102 can be introduced into the first space-side opening 40A without being affected by the rotation of the rotor shaft 11.

[0049] The radial flow passages 401, the axial flow passages 402, and the other-side flow passages 403 each have a circular cross-sectional shape and extend so that the flow passage areas are constant. The radial flow passages 401, the axial flow passages 402, and the other-side flow passages 403 are formed to have the same flow passage areas.

[0050] According to the cold energy power generation device 1 of the present disclosure, the heat medium introduced into the heat medium flow path 63 from the one-side inlet passage 64A passes through the first-stage stator vanes 23A and the first-stage rotor blades 23B of the first-stage turbine device 23 and is introduced into the second-stage turbine device 24. The heat medium introduced into the second-stage turbine device 24 passes through the second-stage stator vanes 24A and the second-stage rotor blades 24B of the second-stage turbine device and is discharged from the other-side discharge passage 64B. Furthermore, a part of the heat medium leaks and flows into the inside of the inner casing 61 instead of the heat medium flow path 63. The heat medium that has flowed into the inner casing 61 flows through the first space 614 and the pressure equalizing flow path 40 in this order inside the inner casing 61, and then flows into the radial gap 241 from the radial gap side opening 40B.

[0051] The pressure in the heat medium passage 63 downstream of the second-stage stator vane 24A is lower than that at the inlet of the heat medium passage 63 because the heat medium passes through the first-stage stator vane 23A, the first-stage rotor blade 23B, and the second-stage stator vane 24A in this order in the heat medium passage 63. Furthermore, the pressure in the heat medium passage 63 downstream of the second-stage stator vane 24A is lower than the pressure in the radial gap 241 of the heat medium that has passed through the inside of the inner casing 61. Therefore, the heat medium that has passed through the inner casing 61 and flowed into the radial gap 241 flows from the radial inside to the radial outside of the radial gap 241 and flows out into the heat medium passage 63 downstream of the second-stage stator vane 24A. Then, the pressure inside the inner casing 61 decreases, and the pressure around the thrust bearing device 102 also decreases. This reduces windage loss due to the thrust bearing device 102 and suppresses a decrease in generator performance.

[0052] The pressure inside the inner casing 61 becomes lower downstream due to pressure losses caused by the second journal bearing device 104, the motor rotor 81, the motor stator 82, etc. In this embodiment, the thrust bearing device 102 is disposed on the other side (downstream) of the generator 8, so the pressure around the thrust bearing device 102 decreases, which further reduces windage loss caused by the thrust bearing device 102 and suppresses deterioration in generator performance.

[0053] Moreover, the first space 614 may be formed on the other side of the thrust bearing device 102 .

[0054] With this configuration, the pressure equalizing passage 40 communicates between the first space 614 and the radial gap 241 without passing through the radially outer side of the thrust bearing device 102, which has a larger diameter. Therefore, compared to when the pressure equalizing passage 40 passes through the radially outer side of the thrust bearing device 102, the outer diameter of the inner casing 61 can be made smaller, and the entire cold energy power generation device 1 can be simplified.

[0055] Note that, as shown in Fig. 4, a plurality of pressure equalizing channels 40 may be formed at intervals in the circumferential direction. In this case, the plurality of pressure equalizing channels 40 may be arranged at equal intervals in the circumferential direction. Also, in Fig. 4, the cross-sectional shape of the pressure equalizing channel 40 is circular, but it may be non-circular, for example, elliptical or rectangular.

[0056] FIG. 5 is a schematic diagram of the cross section BB of the cold energy power generation device 1 shown in FIG. In some embodiments, as shown in FIG. 5, the other-side disk portion 113B has a through-hole 50 that communicates the radial gap 241 with a space 615 on the other side of the second stage rotor blade 24B.

[0057] The pressure downstream of the second-stage rotor blade 24B is lower than the pressure in the radial gap 241 defined upstream of the second-stage rotor blade 24B. Therefore, by connecting the radial gap 241 with the space downstream of the second-stage rotor blade 24B through the through-hole 50, the heat medium in the radial gap 241 can be discharged into the space 615, and the pressure inside the inner casing 61 in which the thrust bearing device 102 is disposed can be reduced. This makes it possible to reduce windage loss caused by the thrust bearing device 102.

[0058] Furthermore, the through-hole 50 is formed opposite the radial gap side opening 40B. Therefore, the heat medium that flows out from the radial gap side opening 40B of the pressure equalizing passage 40 can flow into the space 615 through the through-hole 50 of the other-side disk portion 113B, thereby reducing the pressure inside the inner casing 61.

[0059] A plurality of through holes 50 may be formed at intervals in the circumferential direction as shown in Fig. 5. In this case, the plurality of through holes 50 may be arranged at equal intervals in the circumferential direction. Furthermore, although the cross-sectional shape of the through holes 50 is circular in Fig. 5, the cross-sectional shape may be non-circular, such as elliptical or rectangular.

[0060] In the illustrated embodiment, the first space side opening 40A and the radial gap side opening 40B for the same pressure equalizing passage 40 are located on the same axial cross section including the axis of the rotor shaft 11. In other words, the pressure equalizing passage 40 is formed without rotating around the axis CA of the cold energy power generation device 1. With this configuration, the pressure equalizing passage 40 can be easily formed in the inner casing 61.

[0061] As shown in FIG. 2, the cold energy power generation plant 1 further includes a seal portion 26 that seals between the rotor shaft 11 and the inner casing 61 on the other side of the first stage turbine device 23 and on one side of the generator 8.

[0062] In the illustrated embodiment, the seal portion 26 seals the gap between the inner circumferential surface 611 of the inner casing 61 and the outer circumferential surface of the shaft portion 111 of the rotor shaft 11 on the other side of the first stage turbine device 23 and on one side of the generator 8. The seal portion 26 may include a mechanical seal, or may include a labyrinth seal provided by machining the shaft portion 111 or the inner casing 61 to have recesses and projections.

[0063] According to this configuration, it is possible to seal off the heat medium leaking from the high-pressure region of the first-stage turbine device 23 into the inside of the inner casing 61, and therefore it is possible to maintain a lower pressure inside the inner casing 61 compared to a case where no seal member is provided. As a result, it is possible to reduce windage loss caused by the thrust bearing device 102 inside the inner casing 61. Furthermore, since the heat medium that has passed through the first stage rotor blades 23B can be prevented from leaking into the inside of the inner casing 61, the reduction in the heat medium flowing through the heat medium flow path 63 can be suppressed compared to when no sealing member is provided, and the efficiency of the second stage turbine device 24 can be improved.

[0064] 2 and 3, the above-described cold energy power generation device 1 does not include a member for sealing between the rotor shaft 11 and the inner casing 61 on the other side of the generator 8 inside the inner casing 61. In other words, a sealing member such as a mechanical seal or labyrinth seal like the above-described seal portion 26 is not provided on the other side of the generator 8 inside the inner casing 61.

[0065] According to this configuration, no seal member that would prevent the heat medium from leaking from inside the inner casing 61 to the low-pressure region of the second-stage turbine device 24 is provided, so the pressure inside the inner casing 61 can be kept low compared to when a seal member is provided. This makes it possible to reduce the thrust force acting on the rotor shaft 11 and windage loss (loss) caused by the thrust bearing device 102 inside the inner casing 61.

[0066] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0067] The contents of the above-described embodiments can be understood, for example, as follows.

[0068] A cold energy power generation device (1) according to one aspect includes: A cold energy power generation device (1) provided in a heat medium circulation line configured to circulate a heat medium for heating liquefied gas, A rotor shaft (11); a generator (8) including a motor rotor (81) supported on an outer peripheral surface of the rotor shaft (11) and a motor stator (82) arranged opposite to the motor rotor (81); an inner casing (61) that houses the generator (8); an outer casing (62) disposed on an outer peripheral side of the inner casing (61) and defining a heat medium flow path (63) between the outer casing (62) and the inner casing (61); a first stage turbine unit (23) disposed in the heat medium flow path (63) and disposed on one side of the generator (8) in the axial direction of the rotor shaft (11); a second stage turbine unit (24) disposed in the heat medium flow path (63) and on the other side of the generator (8) in the axial direction of the rotor shaft (11); a journal bearing device (first journal bearing device 103) disposed on the other side of the generator (8) on the inner peripheral side of the inner casing (61); a thrust bearing device (102) disposed on the one side of the journal bearing device (103) on the inner peripheral side of the inner casing (61), the second-stage turbine unit (24) includes a second-stage stator vane (24A) and a second-stage rotor blade (24B) provided on the other side of the second-stage stator vane (24A), the rotor shaft (11) includes a disk portion (113B) extending along a radial direction and supporting the second-stage rotor blades (24B) of the second-stage turbine device (24); a radial gap (241) connected to the heat medium flow path (63) on the other side of the second stage stator vane (24A) is defined between the disk portion (113B) and a second end surface (613) of the inner casing (61), the second end surface being the other end surface of the inner casing (61); The inner casing (61) is formed with at least one pressure equalizing flow path (40) that connects a first space (614) on one side of the journal bearing device (103) inside the inner casing (61) with the radial gap (241).

[0069] According to the cold-energy power generation device of the present disclosure, a radial gap is defined that is connected to the heat transfer medium flow path downstream of the second-stage stator vane, and the inner casing is formed with at least one pressure equalizing flow path that connects the radial gap to a first space inside the inner casing on one side of the journal bearing device. The heat transfer medium passes through the pressure equalizing flow path from the first space, flows from the inside to the outside in the radial gap, and flows out into the heat transfer medium flow path. The heat transfer medium flows through a heat transfer passage defined between the inner casing and the outer casing, first through the first stage turbine device and then through the second stage turbine device. In other words, the pressure in the radial gap defined downstream of the second stage stator vanes is lower than the pressure upstream of the second stage stator vanes. Therefore, by connecting the first space and the radial gap through the pressure equalizing passage, the pressure inside the inner casing in which the thrust bearing device is disposed can be reduced, thereby reducing windage loss of the thrust bearing device and suppressing deterioration of generator performance.

[0070] (2) The cold energy power generation device (1) according to another aspect is the cold energy power generation device according to (1), The thrust bearing device (102) is disposed on the other side of the generator (8).

[0071] Inside the inner casing body, the pressure on the other side of the generator is lower than the pressure on one side of the generator. With this configuration, by arranging the thrust bearing device on the other side of the generator, it is possible to reduce the pressure in the area where the thrust bearing device is arranged, and it is possible to reduce windage loss caused by the thrust bearing device.

[0072] (3) The cold energy power generation device (1) according to yet another aspect is the cold energy power generation device according to (2), The first space (614) is defined on the other side of the thrust bearing device (102).

[0073] With this configuration, the pressure equalizing passage communicates between the first space and the radial gap without passing through the radially outer side of the thrust bearing device, which has a larger diameter. Therefore, compared to when the pressure equalizing passage passes through the radially outer side of the thrust bearing device, the outer diameter of the inner casing body can be made smaller, and the entire cold energy power generation system can be simplified.

[0074] (4) The cold energy power generation device (1) according to yet another aspect is the cold energy power generation device according to (3), The journal bearing device (103) includes a main bearing (103A) and an auxiliary bearing (103B).

[0075] With this configuration, even if the main bearing is no longer able to support the rotor shaft due to a shutdown of the cold energy power generation device or some other problem, the rotor shaft can still be supported by the auxiliary bearing.

[0076] (5) A cold energy power generation device (1) according to yet another aspect is the cold energy power generation device according to any one of (1) to (4), The disk portion (113B) has at least one through-hole (50) that penetrates in the axial direction of the rotor shaft (11).

[0077] The pressure downstream of the second-stage rotor blades is lower than the pressure in the radial gap defined upstream of the second-stage rotor blades. Therefore, with this configuration, the through-holes connect the radial gap with the space downstream of the second-stage rotor blades, allowing the heat transfer medium in the radial gap to flow into the space, thereby lowering the pressure inside the inner casing in which the thrust bearing device is disposed. This reduces windage loss caused by the thrust bearing device 102.

[0078] (6) A cold energy power generation device (1) according to yet another aspect is the cold energy power generation device according to any one of (1) to (5), The turbine further includes a seal portion (26) that seals between the rotor shaft (11) and the inner casing (61) on the other side of the first stage turbine device (23) and on the one side of the generator (8).

[0079] With this configuration, it is possible to seal off the heat transfer medium leaking from the high-pressure region of the first-stage turbine device into the inner casing, and therefore the pressure inside the inner casing can be kept lower than when no seal member is provided, thereby reducing the thrust force acting on the rotor shaft and windage loss caused by the thrust bearing device inside the inner casing. Furthermore, since the heat transfer medium that has passed through the first-stage rotor blades can be prevented from leaking into the inside of the inner casing body, the reduction in the heat transfer medium flowing through the heat transfer medium flow path can be suppressed compared to when no sealing member is provided, thereby improving the efficiency of the second-stage turbine device.

[0080] (7) The cold energy power generation device (1) according to yet another aspect is the cold energy power generation device according to (6), No sealing member is provided between the rotor shaft (11) and the inner casing (61) on the other side of the generator (8) inside the inner casing (61).

[0081] With this configuration, since no seal member that would prevent the heat transfer medium from leaking from inside the inner casing to the low-pressure region of the second-stage turbine device is provided, the pressure inside the inner casing can be kept lower than when a seal member is provided, thereby reducing the thrust force acting on the rotor shaft and windage loss (loss) caused by the thrust bearing device inside the inner casing body. [Explanation of symbols]

[0082] 1. Cold energy power generation equipment 2. Liquefied gas supply lines 3. Condenser 4 Heated fluid supply line 5. Heat and cold pump 6 Casing 61 Inner casing 62 outer casing 7. Evaporator 8. Generator 81 Motor rotor 82 Motor stator 9 Heat medium circulation line 10 ships 10A Floating Structure 10B Liquefied Gas Terminal 11 rotor shaft 111 Shaft section 112 Thrust Collar 112A One side 112B Other side 113A One side disc part 113B Other side disc part 21 Liquefied gas storage device 22 Liquefied gas pump 23 First stage turbine unit 23A 1st stage stator vane 23B 1st stage rotor blade 24 Second stage turbine unit 24A 2nd stage stator vane 24B 2nd stage rotor blade 241 Radial clearance 26 Seal part 40 Equal pressure channel 40A First space side opening 40B Radial clearance opening 401 Radial flow path 402 Axial flow path 403 Other side flow path 42 Heated fluid pump 50 through holes 63 Heat transfer medium flow path 64A One-side entrance 64B Other side discharge path 65A Inlet Casing 65B Outlet Casing 66A One side cover 66B Other side cover 100 Cold energy power generation system 102 Thrust bearing device 102A One-side thrust bearing 102B Other side thrust bearing 102B1 End 103 First journal bearing device 103A Main bearing 103B Auxiliary bearing 104 Second journal bearing device 104A Main bearing 104B Auxiliary bearing 610 Space 611 Inner surface 612 Outer surface 613 Other side end face 615 The other side of the space 616 Circumferential clearance 621 Inner surface CA axis

Claims

1. A cold energy power generation device provided in a heat medium circulation line configured to circulate a heat medium for heating a liquefied gas, A rotor shaft; a generator including a motor rotor supported on an outer peripheral surface of the rotor shaft and a motor stator disposed opposite the motor rotor; an inner casing that houses the generator; an outer casing disposed on an outer circumferential side of the inner casing and defining a heat medium flow path between the outer casing and the inner casing; a first stage turbine device disposed in the heat transfer medium flow path and disposed on one side of the generator in the axial direction of the rotor shaft; a second stage turbine device disposed in the heat medium flow path and disposed on the other side of the rotor shaft in the axial direction relative to the generator; a journal bearing device disposed on the other side of the generator on an inner peripheral side of the inner casing; a thrust bearing device disposed on the one side of the journal bearing device on the inner peripheral side of the inner casing, the second stage turbine device includes a second stage stator vane and a second stage rotor blade provided on the other side of the second stage stator vane, the rotor shaft includes a disk portion extending radially and supporting the second stage rotor blades of the second stage turbine device; a radial gap connected to the heat medium flow path on the other side of the second stage stator vane is defined between the disk portion and the other end face of the inner casing, At least one pressure equalizing flow path is formed in the inner casing, the pressure equalizing flow path communicating the radial gap with a first space located on the one side of the journal bearing device inside the inner casing, the thrust bearing device is disposed on the other side of the generator, The thrust bearing device is a one-side thrust bearing disposed so as to be able to abut against the one-side side surface, which is the one side surface of a thrust collar provided on the rotor shaft; a second-side thrust bearing arranged to be able to abut against a second-side side surface that is the second side surface of the thrust collar, the second-side thrust bearing being arranged on the first space side with respect to the thrust collar, Cold energy power generation equipment.

2. The one-side thrust bearing and the other-side thrust bearing are configured by magnetic bearings. The cold energy power generation device according to claim 1 .

3. the first space is defined on the other side of the thrust bearing device; The cold energy power generation device according to claim 1 .

4. The journal bearing device includes a main bearing and an auxiliary bearing. The cold energy power generation device according to claim 3 .

5. The disk portion has at least one through-hole that penetrates in the axial direction of the rotor shaft. The cold energy power generation device according to any one of claims 1 to 4.

6. a seal portion that seals between the rotor shaft and the inner casing on the other side of the first stage turbine device and on the one side of the generator, The cold energy power generation device according to any one of claims 1 to 4.

7. a sealing member is not provided between the rotor shaft and the inner casing on the other side of the generator inside the inner casing; The cold energy power generation device according to claim 6.

8. A cold energy power generation system comprising the cold energy power generation device according to any one of claims 1 to 4.

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