Electric steam compressor and cogeneration steam generation system including the same

Abstract

To provide an electric steam compressor capable of cooling an electric motor by cooling fluid without affecting steam to be compressed.SOLUTION: The steam compressor 37 includes a suction part 48 that negative-pressure steam, an impeller 49 that compresses the negative-pressure steam sucked from the suction part 48 to a positive pressure, a rotary shaft 47 that rotationally drives the impeller 49, a main body part 45 that houses the rotary shaft 47, an electric motor that drives the rotary shaft 47, a cooling flow path 59 that is formed in a gap between the main body part 45 and the rotary shaft 47 and through which cooling air for cooling the electric motor flows, and a seal part 57 that is provided in the cooling flow path 59 and prevents a flow of fluid to the impeller.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electric steam compressor that compresses steam and a steam generation system for combined heat and power generation that includes the same. [Background technology]

[0002] Patent Document 1 discloses a cogeneration system (combined heat and power supply system) that generates steam using engine cooling water that cools the engine jacket of a power generation engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6463181 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the cogeneration system described in Cited Document 1 requires engine coolant at 100°C or higher to generate steam. Therefore, if the engine coolant is below 100°C, a heating means is required to raise the temperature to 100°C or higher.

[0005] On the other hand, generating steam using heat below 100°C requires the use of negative pressure water below atmospheric pressure. Negative pressure steam generated from negative pressure water needs to be pressurized by a steam compressor, considering various applications. When a steam compressor is driven by an electric motor, the motor needs to be cooled to improve efficiency and ensure stable operation. However, when compressing negative pressure steam, there is a risk that the cooling fluid will flow into the negative pressure steam due to the pressure difference. The flow of cooling fluid (such as air) into negative pressure steam is undesirable, as it reduces compression efficiency and diminishes the value of the steam provided by the steam compressor.

[0006] Even if the steam compressor draws steam at positive pressure rather than negative pressure, there is a problem that the quality of the compressed steam cannot be maintained if the cooling fluid that cools the motor flows into and mixes with the positive pressure steam. Conversely, if steam gets mixed into the cooling fluid, there is a problem that the motor may malfunction.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide an electric steam compressor that can cool an electric motor with a cooling fluid without affecting the steam being compressed, and a steam generation system for combined heat and power supply that includes the same. [Means for solving the problem]

[0008] An electric steam compressor according to one aspect of the present disclosure includes an intake section that draws in steam, a compression section that compresses the steam drawn in through the intake section, a rotating shaft that rotates and drives the compression section, a main body that houses the rotating shaft, an electric motor that drives the rotating shaft, a cooling flow path formed in a gap between the main body and the rotating shaft and through which a cooling fluid flows to cool the electric motor, and a seal provided in the cooling flow path that prevents the flow of fluid to the compression section.

[0009] A steam generation system for combined heat and power supply according to one embodiment of the present disclosure includes a steam generator that generates steam by heating negative pressure water with hot water obtained from cooling water that cools a power generation engine, a steam supply unit that supplies the steam generated by the steam generator to a demand destination, a water supply unit that supplies water to the steam generator, a pressure reducing valve provided in the water supply unit that reduces the pressure of the water to below atmospheric pressure, and the electric steam compressor described in claim 1 that is provided in the steam supply unit and increases the pressure of the steam. [Effects of the Invention]

[0010] The motor can be cooled by the cooling fluid without affecting the negative pressure vapor that is being compressed. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a schematic diagram illustrating a combined heat and power system according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a vertical cross-sectional view showing a schematic configuration of the steam compressor of FIG. [Figure 3] FIG. 3 is a longitudinal sectional view showing the separator of FIG. 2. [Figure 4] FIG. 4 is a vertical cross-sectional view showing a modified example of the separator of FIG. 3. [Figure 5] FIG. 3 is a vertical cross-sectional view showing a modified example of the steam compressor of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 1 shows a cogeneration system 1 including a steam compressor 37 according to this embodiment. The cogeneration system 1 includes a gas engine (power generation engine) 3, an exhaust gas boiler 5, a CO2 recovery device 7, and a steam generation system 9.

[0013] The gas engine 3 is operated using gas fuel such as city gas as fuel. A generator (not shown) is driven by the gas engine 3 to generate electric power. The electric power generated by the generator is supplied to a consumer. Note that instead of the gas engine 3, other power generation engines such as a gas turbine engine or a diesel engine using oil fuel may be used. Also, there may be multiple gas engines 3.

[0014] The exhaust gas boiler 5 generates steam from the exhaust gas discharged from the gas engine 3. After heat exchange in the exhaust gas boiler 5, the exhaust gas passes through an exhaust gas flow path 11 and is led to the CO2 recovery device 7. The steam generated in the exhaust gas boiler 5 is led to a boiler steam supply path 13 and supplied to an external demand destination.

[0015] The CO2 recovery device 7 recovers CO2 (carbon dioxide) from the exhaust gas guided from the gas engine 3. The CO2 recovery device 7 employs a chemical absorption method using an absorbing liquid such as an amine absorbing liquid that chemically absorbs CO2.

[0016] The CO2 recovery system 7 includes an absorption tower 15 and a regeneration tower 16. In the absorption tower 15, an amine absorbing solution is brought into contact with the flue gas to absorb CO2 in the flue gas. A lean solution supply unit 15a is connected to the absorption tower 15, which supplies a lean solution from which CO2 has been desorbed and whose CO2 concentration has been made lean. The amine absorbing solution (lean solution) supplied from the lean solution supply unit 15a absorbs CO2 in the flue gas while flowing through the absorption tower 15. The rich solution, which has absorbed CO2 in the absorption tower 15 and whose CO2 concentration has been made rich, is sent to the rich solution supply unit 16a via a heat exchanger 20 by an absorption tower pump 22.

[0017] The heat exchanger 20 is a non-contact heat exchanger, and exchanges heat between the lean solution supplied from the regeneration tower pump 18 and the rich solution supplied from the absorption tower pump 22 .

[0018] The exhaust gas from which CO2 has been removed by the amine absorbent is discharged from the absorption tower 15 to the outside.

[0019] In the regeneration tower 16, CO2 is desorbed from the rich solution that has absorbed CO2. The amine absorption solution (rich solution) supplied from the rich solution supply unit 16a into the regeneration tower 16 is heated by the heat exchanger 20, thereby providing the amount of heat required for the endothermic reaction of desorbing CO2. CO2 is desorbed from the rich solution while the amine absorption solution (rich solution) supplied from the rich solution supply unit 16a flows through the regeneration tower 16. The CO2 desorbed from the rich solution is discharged from the regeneration tower 16 and led to a CO2 storage unit (not shown).

[0020] A reboiler 17 that heats the amine absorption solution is connected to the regeneration tower 16. The reboiler 17 heats the amine absorption solution extracted from the regeneration tower 16 via an absorption solution recovery line 16b. Steam introduced from a boiler steam branch line (steam supply section) 13a branched from the boiler steam supply line 13 is used as the heat source for the reboiler 17. The amine absorption solution heated by the reboiler 17 is returned to the regeneration tower 16 via an absorption solution return line 16c. The heated amine absorption solution (lean solution) is extracted from the bottom of the regeneration tower 16 and sent to a heat exchanger 20 by a regeneration tower pump 18.

[0021] The steam generating system 9 is connected to the gas engine 3. The steam generating system 9 includes a hot water circuit 25 through which hot water circulates between the gas engine 3 and the steam generating system 9, and a steam generator 27 to which the hot water circuit 25 is connected.

[0022] The hot water circuit 25 is a closed-loop flow path for circulating hot water guided from the gas engine 3. The hot water is heated by heat exchange with the cooling water that cools the gas engine 3, and its temperature is reduced to less than 100°C. A hot water pump 33 is provided in the hot water circuit 25. The operation of the hot water pump 33 is controlled by a control unit (not shown). The cooling water that cooled the gas engine 3 may be directly supplied to the hot water circuit 25, or the hot water circuit 25 may be formed by the cooling water circulation path itself. Alternatively, the cooling water that cools the gas engine 3 may be drawn to the outside of the gas engine 3 through a water supply pipe, and the hot water in the hot water circuit 25 may be heated by a heat exchanger provided outside the gas engine 3. Here, the cooling water that cools the gas engine 3 also includes cooling water that cools the oil circulating or passing through inside the gas engine 3. The power generation engine is not limited to a gas engine, and a gas turbine engine may also be used.

[0023] The steam generator 27 is a non-contact heat exchanger in which hot water and feed water exchange heat without contact, and a partition-type heat exchanger such as a plate-type heat exchanger, a shell-and-plate heat exchanger, or a shell-and-tube heat exchanger can be used.

[0024] A water supply line (water supply unit) 29 that supplies water to be heated is connected to the steam generator 27. A pressure reducing valve 35 is provided in the water supply line 29. The pressure reducing valve 35 reduces the pressure of the water supply, which is at atmospheric pressure at room temperature (e.g., 20°C), to produce negative pressure water. The opening of the pressure reducing valve 35 is controlled by a control unit (not shown). The pressure reducing valve 35 is controlled in coordination with the operation of each steam compressor 37 as necessary so that the interior of the steam generator 27 is at a desired pressure.

[0025] A steam supply path (steam supply unit) 31 through which negative pressure steam generated by the steam generator 27 flows out is connected to the steam generator 27. The negative pressure steam generated by the steam generator 27 is generated by hot water of less than 100°C supplied from the hot water circuit 25. For example, when the pressure of the water supply is -0.054 MPaG, saturated steam is at 80°C, so negative pressure steam can be generated with hot water of about 85°C.

[0026] The steam supply line 31 is provided with a plurality of steam compressors (electric steam compressors) 37 and a supply rate adjuster 39. Each steam compressor 37 compresses the negative pressure steam to above atmospheric pressure. Examples of the steam compressor 37 include positive displacement compressors such as screw compressors and claw compressors, as well as turbo compressors. Operation of the steam compressor 37 reduces the pressure in the flow path from its upstream side to the downstream side of the pressure reducing valve 35. The steam compressor 37 is driven by an electric motor, and its rotation speed is controlled by a control unit (not shown). The capacity of the steam compressor 37 may be increased or decreased by increasing or decreasing the rotation speed of the electric motor. Alternatively, the rotation speed may be fixed and increased or decreased by providing a bypass line from the discharge side of the compressor to the suction side, and installing a control valve in the line to change the pressure loss in the line. In addition, in this embodiment shown in FIG. 1, four steam compressors 37 are arranged in series, but the number is not limited to one, and may be one, two, three, five or more.

[0027] The supply amount adjusting unit 39 separates the pressurized steam into gas and liquid and adjusts the flow rate of the steam to be discharged. The flow rate of the steam discharged from the supply amount adjusting unit 39 is controlled by a control unit (not shown).

[0028] Furthermore, the steam flow rate can be adjusted by coordinating the control of the capacity of the steam compressor 37 with the control of the opening of the pressure reducing valve 35. For example, the steam flow rate can be increased by increasing the capacity of the steam compressor 37 and increasing the opening of the pressure reducing valve 35. This makes it possible to increase the steam flow rate while keeping the circulation flow rate of the hot water circuit 25 and the amount of heat input to the steam generator 27 constant. Furthermore, increasing the capacity of the steam compressor 37 also increases the total amount of heat energy input per hour by steam compression.

[0029] A portion of the supply water is guided from the water supply passage 29 to the downstream side of each steam compressor 37 and to the supply amount adjustment unit 39 via a water injection pipe 41. The supply water guided from the water injection pipe 41 is injected to cool the pressurized steam and the steam guided to the supply amount adjustment unit 39. Note that the water injection pipe 41 may be provided with a pressure boosting means (such as a pump) to obtain the pressure required for injection.

[0030] The pressurized steam flowing out from the supply amount adjustment unit 39 passes through the steam supply path 31 and merges with the boiler steam branch path 13a. In this way, the steam guided from the supply amount adjustment unit 39 merges with the boiler steam branch path 13a and is guided to the reboiler 17 of the CO2 recovery unit 7.

[0031] A turbine 14 is provided in the boiler steam branch passage 13a upstream of a joining position P1 where the boiler steam branch passage 13a joins the steam supply passage 31. The turbine 14 reduces the pressure of the steam and recovers pressure energy. Note that an expansion valve may be provided instead of the turbine 14.

[0032] The control unit is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and computer-readable storage media. A series of processes for realizing various functions is stored in, for example, a storage medium in the form of a program. The CPU reads this program into RAM and executes information processing and arithmetic operations to realize various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0033] The above-described cogeneration system 1 operates as follows. Power is generated by operating the gas engine 3, and the exhaust gas discharged from the gas engine 3 passes through the exhaust gas boiler 5 and is led to the CO2 recovery unit 7. Steam generated in the exhaust gas boiler 5 passes through the boiler steam supply path 13 and is supplied to the demand destination. A portion of the steam generated in the exhaust gas boiler 5 is branched off at the boiler steam branch path 13a, depressurized by the turbine 14, and then led to the reboiler 17 of the CO2 recovery unit 7. Steam generated in the steam generator 27 and pressurized by each steam compressor 37 also flows into the boiler steam branch path 13a.

[0034] Hot water of less than 100°C heated by the cooling water that cooled the gas engine 3 circulates through the hot water circuit 25. The hot water of less than 100°C is reduced in pressure by a pressure reducing valve 35 to a negative pressure, and is then heated in a steam generator 27 to generate negative pressure steam. The negative pressure steam generated in the steam generator 27 passes through a steam supply path 31, is pressurized to atmospheric pressure or higher by a plurality of steam compressors 37, and is then guided to a supply amount adjustment unit 39. The steam, the flow rate of which has been adjusted by the supply amount adjustment unit 39, passes through the steam supply path 31 and merges with the boiler steam branch path 13a. The steam that has merged at the boiler steam branch path 13a is guided to the reboiler 17 and is used as a heat source.

[0035] In the CO2 recovery unit 7, CO2 is recovered from the exhaust gas guided from the gas engine 3 in an absorption tower 15, and the exhaust gas after CO2 absorption is released to the outside. In a regeneration tower 16, an amine absorption solution is heated by a reboiler 17. CO2 desorbed from the amine absorption solution is discharged from the regeneration tower 16 and sent to a CO2 storage section.

[0036] <Steam Compressor 37> Next, the steam compressor 37 shown in Fig. 1 will be described. The steam compressor 37 described below is the steam compressor 37 located most upstream in Fig. 1 and drawing in negative pressure steam. However, as will be described later, the present invention can also be applied to steam compressors 37 that draw in positive pressure steam, such as the second or subsequent steam compressors 37 in Fig. 1.

[0037] As shown in Fig. 2, the steam compressor 37 includes a main body 45, a rotating shaft (rotating shaft body) 47 housed in the main body 45, and impellers (compression parts) 49 provided on both ends of the rotating shaft 47. The impellers 49 are, for example, impellers of a centrifugal compressor. Although Fig. 2 shows two impellers, a left impeller 49L and a right impeller 49R, the impeller 49 may be provided on only one side of the rotating shaft 47.

[0038] A suction section 48 that sucks in negative pressure steam guided from the steam supply passage 31 (see FIG. 1) is provided upstream of the impeller 49. The negative pressure steam compressed by the impeller 49 is discharged from a discharge section 50 to the downstream side of the supply amount adjustment section 39 (see FIG. 1).

[0039] The rotating shaft 47 is provided with two radial bearings 51 (51L, 51R) spaced apart in the axial direction. The radial bearings 51 rotatably support the rotating shaft 47 relative to the main body 45. The rotating shaft 47 is supported in the thrust direction (axial direction) by one thrust bearing 53. The thrust bearing 53 is provided between the right radial bearing 51R and the right impeller 49R in FIG. 2. The radial bearing 51 and the thrust bearing 53 are, for example, gas bearings.

[0040] Rotating shaft 47 is provided with rotor 55 of an electric motor (electric motor) between two radial bearings 51L, 51R. A permanent magnet, for example, is used as rotor 55. A stator 56 of the electric motor is provided on main body 45 facing rotor 55. The current supplied to the windings of stator 56 is controlled by a control unit, thereby making the rotation speed of rotating shaft 47 variable.

[0041] Seal portions 57 (57L, 57R) are provided on both sides of the rotating shaft 47. In FIG. 2, the left seal portion 57L is provided between the left radial bearing 51L and the left impeller 49L, and the right seal portion 57R is provided between the thrust bearing 53 and the right impeller 49R. Each seal portion 57 seals the fluid flow in the gap between the rotating shaft 47 and the main body portion 45. Each seal portion 57 is provided so as to form a seal space surrounded by two seal members spaced apart in the axial direction. Fluid that has passed through the seal members flows into this seal space.

[0042] A cooling passage 59 through which cooling air (cooling fluid) flows is formed in the gap between the rotating shaft 47 and the main body 45, spanning between the seal portions 57 on both sides. A plurality of cooling air introduction passages (cooling fluid introduction passages) 61 (61L, 61R) that guide cooling air from the outside of the main body 45 are connected to the cooling passage 59. Each of the cooling air introduction passages 61L, 61R is formed in the radial direction of the main body 45. In FIG. 2, the left cooling air introduction passage 61L is provided between the left seal portion 57L and the left radial bearing 51L. The right cooling air introduction passage 61R is provided between the thrust bearing 53 and the right seal portion 57R.

[0043] The cooling air introduced from the left cooling air inlet passage 61L is divided into two directions by the cooling passage 59, one of which flows left along the rotating shaft 47 as indicated by arrow C1 and into the left seal portion 57L. The other of which flows right along the rotating shaft 47 as indicated by arrow C2 and passes through the left radial bearing 51L, rotor 55, and right radial bearing 51R before flowing to the thrust bearing 53.

[0044] The cooling air introduced from the right cooling air inlet passage 61R is divided into two directions by the cooling passage 59, one of which flows leftward along the rotating shaft 47 as indicated by arrow C3 and flows toward the thrust bearing 53. The other of which flows rightward along the rotating shaft 47 as indicated by arrow C4 and flows into the right seal portion 57R.

[0045] Each seal portion 57L, 57R is connected to a discharge flow path 63 (63L, 63R) that discharges the fluid that has reached the seal portion 57L, 57R to the outside of the main body portion 45. Each discharge flow path 63L, 63R is formed in a radial direction. A portion of the main steam (see arrow S2) compressed (pressurized) by each impeller 49L, 49R (see arrow S1) is guided to each seal portion 57L, 57R. The portion of the steam (arrow S2) includes steam that leaks from gaps that inevitably exist in the structure of the steam compressor 37, and is guided to each seal portion 57L, 57R via a steam discharge flow path 65. Cooling air guided from the cooling flow path 59 also flows into each seal portion 57L, 57R (see arrows C1, C4).

[0046] The outlet side of the left discharge flow path 63L is connected to a separator 67. The separator 67 separates steam and air. The upstream end of a circulation flow path 69 is connected to the separator 67. The downstream end of the circulation flow path 69 is connected to the upstream side of the suction section 48 of the steam supply path 31 (see Figure 1), etc. The circulation flow path 69 allows the steam separated by the separator 67 to merge with the negative pressure steam. A vacuum pump 71 (pressure reduction section, discharge section) is connected to the separator 67. The vacuum pump 71 discharges the air separated by the separator 67 to the outside (such as the atmosphere).

[0047] The outlet side of the right discharge flow path 63R is connected to a vacuum pump (pressure reduction unit) 73. The steam and air guided from the right discharge flow path 63R are discharged to the outside (such as the atmosphere) by the vacuum pump 73. Note that a pressure reduction unit such as an ejector may be used instead of the vacuum pumps 71 and 73.

[0048] The flow path cross-sectional area of ​​the outlet of the exhaust flow path 63 is set to be larger than the flow path cross-sectional area of ​​the cooling air introduction path 61. This allows the throat position of the cooling air flow to be shifted upstream of the exhaust flow path 63, i.e., to the cooling flow path 59 side, and the pressure in the cooling flow path 59 that cools the electric motor is reduced compared to when the throat position is located on the exhaust flow path 63 side.

[0049] A second exhaust flow path 75 is provided in the space that accommodates the thrust bearing 53. The cooling air that has reached the thrust bearing 53 is exhausted to the outside from the second exhaust flow path 75 (see arrows C2 and C3). The air may be exhausted directly from the second exhaust flow path 75 to the outside of the main body 45, or may be exhausted using a vacuum pump 73 via a connecting flow path 77 that is equipped with an on-off valve 77a.

[0050] FIG. 3 shows a specific configuration of the separator 67. The separator 67 includes an inner cylinder 79 and an outer cylinder 81. The inner cylinder 79 extends vertically. An inlet portion 79a located at the lower end of the inner cylinder 79 is provided to face the flow direction of the main flow of negative pressure steam (see arrow S1). The outlet side of the inner cylinder 79 is connected to the suction portion 48 (see FIG. 2) side of the impeller 49. As a result, all of the negative pressure steam flowing toward the suction portion 48 flows into the inner cylinder 79.

[0051] The outer cylinder 81 is a container that covers the inner cylinder 79, and has an inlet 81a formed on one side. Steam and air are introduced into the outer cylinder 81 from the left exhaust flow path 63L via the inlet 81a. The outer cylinder 81 is provided with an outlet 81b. The vacuum pump 71 is connected to the outlet 81b.

[0052] The steam and air introduced into the outer cylinder 81 from the inlet 81a are separated by gravity in the space between the inner cylinder 79 and the outer cylinder 81, with the air remaining in the upper part of the outer cylinder 81 and the steam moving downward. Therefore, the space between the inner cylinder 79 and the outer cylinder 81 and below the inlet 81a forms the circulation flow path 69 (see FIG. 2). Water that has been drained from the steam is stored below the outer cylinder 81 and is discharged as appropriate.

[0053] The air accumulated in the upper part of the outer cylinder 81 is discharged to the outside (atmosphere) by the vacuum pump 71. The operation of the vacuum pump 71 is preferably controlled by a control unit. Specifically, the amount of air accumulated in the upper part of the outer cylinder 81 is estimated by a pressure sensor, a timer, etc., and when the amount exceeds a predetermined amount, the vacuum pump 71 is started to discharge the air.

[0054] Fig. 4 shows a modified example of the separator 67. As shown in Fig. 4, the inner cylinder 79 extends horizontally. In this way, the inner cylinder 79 may be provided (straight) along the flow direction of the main stream of negative pressure steam (arrow S1).

[0055] The above-described embodiment has the following advantages. The electric motor is cooled by circulating cooling air through a cooling passage 59 formed in the gap between the main body 45 and the rotating shaft 47. The cooling air is prevented from flowing to the impeller 49 by the seal 57, so the cooling air is not mixed with the steam, improving compression efficiency. In particular, since the steam flowing through the suction section 48 is under negative pressure, there is a risk that the cooling air will flow into the negative pressure steam side, so the seal 57 is effective.

[0056] The seal portion 57 is provided with an exhaust flow path 63 to exhaust the cooling air from the main body portion 45 . The steam compressed by the impeller 49 is mainly supplied to the destination. However, some of the steam may leak from gaps that inevitably exist in the structure of an electric steam compressor during or after the pressure is increased. Therefore, a steam exhaust flow path 65 is connected to the seal portion 57 to exhaust some of the steam during or after the pressure is increased. The steam exhaust flow path 65 may also be connected to the exhaust flow path 63.

[0057] The circulation flow path 69 allows the steam flowing out from the discharge flow path 63 to merge with the negative pressure steam flowing into the suction part 48. This allows the recovered steam to be recirculated to the impeller 49, thereby improving compression efficiency.

[0058] The separator 67 separates the steam from the cooling air, and the separated steam is then merged with the negative pressure steam. This prevents the cooling air from being mixed with the recirculated steam, improving compression efficiency.

[0059] By discharging the separated cooling air from the separator 67 by the vacuum pump 71, accumulation of the cooling air in the separator 67 can be prevented.

[0060] The operation of the vacuum pump 71 is controlled in accordance with the amount of cooling air accumulated in the separator 67. This makes it possible to reduce the energy consumed in the operation of the vacuum pump 71 as much as possible.

[0061] By making the flow path cross-sectional area of ​​the discharge flow path 63 larger than the flow path cross-sectional area of ​​the cooling air introduction path 61, the throat position of the cooling air flow can be shifted upstream of the discharge flow path 63, i.e., toward the cooling flow path 59. This reduces the pressure in the cooling flow path 59 that cools the electric motor, suppresses motor windage loss, and improves the performance of the steam compressor 37.

[0062] In the above-described embodiment, the fluid discharged from the right-side discharge flow path 63R is discharged to the outside without passing through the separator 67, but it may also be connected to the separator 67 provided in the left-side discharge flow path 63L.

[0063] The present invention can also be applied to a steam compressor 37 that sucks in positive pressure steam, such as the second or subsequent stage steam compressor 37 in Fig. 1. In this case, although the exhaust flow path 63 is depressurized using vacuum pumps 71 and 73 in the configuration shown in Fig. 2, any pressure reducing unit that creates a pressure lower than that of the sealed space formed by the seal unit 57 may be used. In this case, it is not necessary to use a vacuum source such as a vacuum pump.

[0064] 2, a vacuum pump 71 is connected to the separator 67 to discharge the separated cooling air, but when the cooling air separated by the separator 67 is kept under positive pressure, as shown in Fig. 5, an on-off valve 82 may be provided to discharge the air to the outside air without using the vacuum pump 71. In this case, the opening and closing timing of the on-off valve 82 is controlled by the control unit.

[0065] A pressure-boosting unit 83 such as a blower may be provided to boost the air supplied to the cooling air introduction passage 61 shown in FIG. 2 to a pressure higher than the steam pressure after compression (see FIG. 5). When the pressure-boosting unit 83 is provided, a throttle valve (throttling unit) 85 may be provided instead of the vacuum pumps 71 and 73 shown in FIG. 2 to reduce the amount of leak seal. The throttle amount of the throttle valve 85 is variable by a control unit. Note that the throttle valve 85 may be replaced by a fixed throttle such as an orifice.

[0066] The electric steam compressor and the cogeneration steam generating system including the electric steam compressor described in each of the above-described embodiments can be understood, for example, as follows.

[0067] The electric steam compressor (37) according to the first aspect of the present disclosure includes an intake section (48) that draws in steam, a compression section (49) that compresses the steam drawn in from the intake section, a rotating shaft (47) that rotationally drives the compression section, a main body (45) that houses the rotating shaft, an electric motor that drives the rotating shaft, a cooling flow path (59) formed in a gap between the main body and the rotating shaft and through which a cooling fluid flows to cool the electric motor, and a seal section (57) provided in the cooling flow path that prevents the fluid from flowing to the compression section.

[0068] The electric motor is cooled by circulating a cooling fluid through a cooling passage formed in the gap between the main body and the rotating shaft. The cooling fluid is prevented from flowing into the compression section by a seal, so the cooling fluid is not mixed with the steam, improving compression efficiency. The seal is particularly effective when the steam flowing through the suction section is under negative pressure, as there is a risk that the cooling fluid will flow into the negative pressure steam. Note that the steam drawn into the suction section may also be under positive pressure.

[0069] The electric steam compressor according to a second aspect of the present disclosure is the electric steam compressor of the first aspect, and includes an exhaust flow path (63) connected to the seal portion and discharging the cooling fluid from the main body portion, and a steam exhaust flow path (65) connected to the seal portion or the exhaust flow path.

[0070] An exhaust flow path is provided in the seal section, and the cooling air is exhausted from the main body section. A pressure reducing section (such as a vacuum pump or ejector) can be used to exhaust the cooling air from the main body section. The steam compressed by the compression unit is mainly supplied to the user. However, some of the steam may leak from gaps that inevitably exist in the structure of an electric steam compressor during or after the pressure is increased. Therefore, a steam exhaust flow path is connected to the seal unit to allow some of the steam to be discharged during or after the pressure is increased.

[0071] The electric steam compressor according to a third aspect of the present disclosure is the electric steam compressor of the second aspect, further including a pressure reducing section that reduces the pressure in the discharge passage.

[0072] The pressure reducing section can effectively discharge the fluid guided to the sealing section.

[0073] The electric steam compressor according to a fourth aspect of the present disclosure is the electric steam compressor of the second aspect, further including a pressure booster that boosts the pressure of the cooling fluid guided to the electric motor.

[0074] By increasing the pressure of the cooling fluid introduced to the electric motor by the pressure increasing section, the fluid can be effectively discharged from the discharge flow path via the seal section.

[0075] According to a fifth aspect of the present disclosure, in the electric steam compressor of the fourth aspect, a throttle portion is provided in the discharge flow path.

[0076] The throttle portion can restrict the amount of fluid (cooling fluid and steam) discharged, thereby minimizing the amount of cooling fluid leakage.

[0077] In the electric steam compressor according to a sixth aspect of the present disclosure, in the second aspect, a circulation flow path (69) that merges the discharge fluid with the negative pressure steam flowing into the suction section is connected to the discharge flow path.

[0078] The circulation flow path allows the discharge fluid flowing out of the discharge flow path to merge with the steam flowing into the suction section, which allows the recovered steam to be recirculated to the compression section, improving compression efficiency.

[0079] According to a seventh aspect of the present disclosure, in the electric steam compressor of the sixth aspect, the circulation flow path includes a separator (67) that separates steam from a cooling fluid, and the steam separated by the separator is merged with the steam flowing into the suction portion.

[0080] The separator separates the steam from the cooling fluid (e.g., air), and the separated steam is then combined with the intake steam. This prevents the cooling fluid from mixing with the recirculated steam, improving compression efficiency.

[0081] An electric steam compressor according to an eighth aspect of the present disclosure is the seventh aspect, wherein the separator includes an inner cylinder (79) having an inlet portion formed at a position opposite to the direction of a main stream of steam flowing into the suction portion and an outlet portion (79a) connected to the suction portion side, and an outer cylinder (81) covering the inner cylinder and having an inlet (81a) for introducing the discharged fluid.

[0082] Since the inlet of the inner cylinder faces the direction of the main flow of the intake steam, the steam mainly flows into the inner cylinder and is led to the intake section. The discharge fluid is led into the interior of the outer cylinder from the inlet of the outer cylinder that covers the inner cylinder. As a result, the discharge fluid is separated in the space between the outer and inner cylinders. Generally, steam has a higher specific gravity than the cooling fluid (air), so it can be separated in the space between the outer and inner cylinders. The drained steam flows downward in the separator and is separated.

[0083] The electric steam compressor according to a ninth aspect of the present disclosure is the electric steam compressor of the seventh or eighth aspect, further comprising a discharge part (71) that discharges the cooling fluid separated by the separator to the outside.

[0084] By discharging the separated cooling fluid from the separator by the discharge section, it is possible to prevent the cooling fluid from accumulating in the separator. The exhaust section may be a pressure reducing section such as a vacuum pump or an ejector, or an on-off valve when the separated cooling fluid is at positive pressure.

[0085] The electric steam compressor according to a tenth aspect of the present disclosure is the ninth aspect, further including a control unit that controls operation of the discharge unit in accordance with an amount of cooling fluid accumulated in the separator.

[0086] The operation of the discharge section is controlled according to the amount of cooling fluid accumulated in the separator, which makes it possible to reduce the energy consumed in the operation of the discharge section as much as possible.

[0087] An electric steam compressor according to an eleventh aspect of the present disclosure is in any one of the second to tenth aspects, wherein the cross-sectional area of ​​the discharge flow path is larger than the cross-sectional area of ​​a cooling medium inlet path that introduces the cooling medium into the cooling flow path.

[0088] By making the cross-sectional area of ​​the discharge passage larger than that of the cooling medium inlet passage, the throat position of the fluid flow can be shifted upstream of the discharge passage, i.e., toward the cooling passage, which reduces pressure in the cooling passage that cools the electric motor, suppresses motor windage loss, and improves steam compressor performance.

[0089] A steam generation system (1) for combined heat and power supply according to a first aspect of the present disclosure includes a steam generator that generates steam by heating negative pressure water with hot water obtained from cooling water that cools a power generation engine, a steam supply unit that supplies the steam generated by the steam generator to a demand destination, a water supply unit that supplies water to the steam generator, a pressure reducing valve that is provided in the water supply unit and reduces the pressure of the water to below atmospheric pressure, and an electric steam compressor according to any one of the first to eighth aspects that is provided in the steam supply unit and pressurizes the steam. [Explanation of symbols]

[0090] 1 Combined heat and power system 3 Gas engine (power generation engine) 5. Exhaust gas boiler 7. CO2 capture equipment 9. Steam Generation System 11 Exhaust gas flow path 13 Boiler steam supply line 13a Boiler steam branch (steam supply section) 14 Turbine 15 Absorption Tower 15a Lean solution supply section 16 Regeneration Tower 16a Rich solution supply section 16b Absorbent recovery line 16c Absorbent return line 17 Reboiler 18 Regenerator pump 20 Heat exchanger 22 Absorber pump 25 Hot water circuit 27 Steam Generator 29 Water supply channel (water supply section) 31 Steam supply path (steam supply section) 33 Hot water pump 35 Pressure reducing valve 37 Steam compressor (electric steam compressor) 39 Supply amount adjustment section 41 Water injection pipe 45 Main body 47 Rotating shaft (rotating shaft body) 48 Intake section 49, 49L, 49R impeller (compression section) 50 Discharge part 51, 51L, 51R radial bearings 53 Thrust bearing 55 rotor 56 Stator 57, 57L, 57R seal part 59 Cooling Channel 61, 61L, 61R Cooling air inlet passage (cooling fluid inlet passage) 63, 63L, 63R Discharge flow path 65 Steam exhaust flow path 67 Separator 69 Circulation flow path 71 Vacuum pump (pressure reduction section, exhaust section) 73 Vacuum pump (pressure reducing section) 75 Second discharge flow path 77 Connecting Channel 77a On-off valve 79 Inner cylinder 79a Entrance 81 Outer cylinder 81a entrance 81b Outlet 82 On-off valve 83 Booster section 85 Throttle valve (throttle section)

Claims

1. An intake part for sucking in steam; a compression section that compresses the vapor sucked through the suction section; a rotating shaft that rotates the compression unit; a main body that accommodates the rotating shaft; an electric motor that drives the rotating shaft; a cooling flow path formed in a gap between the main body and the rotating shaft, through which a cooling fluid for cooling the electric motor flows; a seal portion provided in the cooling flow path to prevent fluid from flowing to the compression portion; An electric steam compressor equipped with

2. a discharge flow path connected to the seal portion and configured to discharge a cooling fluid from the main body portion; a steam exhaust flow path connected to the seal portion or the exhaust flow path; The electric steam compressor according to claim 1, further comprising:

3. The electric steam compressor according to claim 2, further comprising a pressure reducing section that reduces the pressure in the discharge passage.

4. 3. The electric steam compressor according to claim 2, further comprising a pressure booster section for boosting the pressure of the cooling fluid introduced to the electric motor.

5. 5. The electric steam compressor according to claim 4, wherein a throttle portion is provided in the discharge passage.

6. The electric steam compressor according to claim 2 , wherein the exhaust passage is connected to a circulation passage for merging an exhaust fluid with the steam flowing into the suction portion.

7. The circulation flow path is provided with a separator that separates the steam from the cooling fluid, The electric steam compressor according to claim 6, wherein the steam separated by the separator is joined to the steam flowing into the suction portion.

8. 8. The electric steam compressor according to claim 7, wherein the separator comprises: an inner cylinder having an inlet formed at a position opposite to a direction of a main stream of steam flowing into the suction portion and an outlet connected to the suction portion; and an outer cylinder covering the inner cylinder and having an inlet for introducing the discharged fluid.

9. 8. The electric steam compressor according to claim 6, further comprising a discharge part for discharging the cooling fluid separated by the separator to the outside.

10. The electric steam compressor according to claim 9, further comprising a control unit that controls the operation of the discharge unit in accordance with the amount of cooling fluid accumulated in the separator.

11. 3. The electric steam compressor according to claim 2, wherein a cross-sectional area of ​​the discharge flow path is larger than a cross-sectional area of ​​a cooling medium inlet path for introducing the cooling medium into the cooling flow path.

12. a steam generator that generates steam by heating negative pressure water with hot water obtained from cooling water that cools the power generation engine; a steam supply unit that supplies the steam generated by the steam generator to a demand destination; a water supply unit that supplies water to the steam generator; a pressure reducing valve provided in the water supply unit to reduce the pressure of the water to below atmospheric pressure; the electric steam compressor according to claim 1, which is provided in the steam supply unit and which pressurizes the steam; 1. A combined heat and power steam generating system comprising:

Images