JP6663269B2 - Compressor - Google Patents

Description

  The present invention relates to a compressor, and more particularly to a compressor used in a gas field that produces natural gas.

  In recent years, with the increase in demand for fossil fuels and the development of mining technology, development has shifted from conventional gas fields to unconventional gas fields, and it is necessary to install compressors in harsh environments directly under gas fields. Has arisen. Immediately below the gas field, a method has been proposed in which a compressor is inserted into a gas well several thousand meters underground, and the gas is compressed at the bottom of the well and sent to the ground. Research on a compressor (downhole compressor) for that purpose Development is taking place.

  In a gas field, underground pressure is high at the beginning of development, but the internal pressure decreases as gas is collected. Natural gas can be spontaneously injected to the ground while the gas field underground pressure is high, but when the pressure falls below the limit, gas cannot be spontaneously injected. It was supposed to be.

  However, even after the underground pressure has fallen to a level that is insufficient to self-inject the gas, substantial amounts of natural gas still remain inside the gas field. Therefore, it is considered that the production capacity of the gas field can be restored by applying a downhole compressor and boosting the pressure immediately below the gas field. Since the downhole compressor described above is installed at the bottom of the gas field or directly below the gas field, the operating environment is very severe.

  Generally, the working fluid of a compressor used in a gas field that produces natural gas is in an operating environment in which not only natural gas but also liquid containing light liquid hydrocarbons called water and condensate are mixed. This is a feature. In particular, immediately below the gas field, there is an environment with a very high liquid fraction. In such an environment, the liquid that has entered the inside of the compressor may lose efficiency due to collision with the impeller, reduce the operating range due to blockage of the flow path due to fouling, generate unstable fluid force, and break. It is believed that eclipse causes impervious thinning of the impeller, and compressors used in gas fields that produce natural gas operate without impairing performance in operating environments where liquids are mixed. Technology is required.

  Patent Document 1 discloses a structure for removing droplets mixed in an impeller of a compressor.

JP 2013-508618 A

  However, the compressor disclosed in Patent Literature 1 cannot sufficiently remove droplets mixed in the impeller.

  Accordingly, an object of the present invention is to provide a compressor that can operate without impairing the efficiency and operating range of the impeller by suppressing the adhesion of liquid to the impeller.

  In order to achieve the above object, a compressor according to the present invention includes a cylindrical casing forming a space, a motor provided in the space of the casing with a gap between the casing, A rotating shaft extending downstream and outputting a rotational driving force of the motor, an impeller fixed to the rotating shaft and compressing a working fluid downstream of the motor, provided in the gap, A first guide blade configured to impart a swirling component to a working fluid passing through the gap and traveling toward the impeller by rotation of the impeller, wherein the casing includes the impeller in the space. And a first drain hole for discharging a liquid component of the working fluid is formed.

  ADVANTAGE OF THE INVENTION According to this invention, adhesion of the liquid component to an impeller can be suppressed, and the compressor which can be operated without reducing the efficiency and operating range of an impeller can be provided.

It is a sectional view of a compressor showing a 1st embodiment of the present invention. It is explanatory drawing of a 1st guide blade. It is sectional drawing of the conventional compressor. It is sectional drawing of the compressor which shows 2nd Embodiment of this invention. It is sectional drawing of the compressor which shows 3rd Embodiment of this invention. It is a sectional view of a compressor showing a 4th embodiment of the present invention.

  Hereinafter, a compressor 1 according to a first embodiment of the present invention will be described with reference to the drawings. The compressor 1 according to the present embodiment is, for example, a turbo type compressor used in a gas well of a gas field that produces natural gas, and is a compressor called a downhole compressor. The working fluid contains not only natural gas but also a liquid component containing light liquid hydrocarbons called water and condensate.

  FIG. 1 shows only a left half of a sectional view of a main part of the compressor 1 according to the first embodiment.

  As shown in FIG. 1, the compressor 1 has a casing 16, a motor 2, a rotating shaft 11, an impeller 10, and first guide blades 15.

  The casing 16 has a tubular shape forming a through space 16a, and has a motor housing 16B, an intermediate portion 16C, and a discharge portion 16D. The motor housing 16B houses the motor 2 and has an inner peripheral surface 16e. The intermediate portion 16C is located downstream of the motor accommodating portion 16B, and has an inclined surface 16e that approaches the rotating shaft 11 as going downstream. That is, in the intermediate portion 16C, the diameter of the through space 16a is reduced by the inclined surface 16e.

  Further, a first liquid storage hole 13 and a first drain port 14 are formed in the intermediate portion 16C. The first liquid storage hole 13 is opened toward a portion of the through space 16a located between the impeller 10 and the first guide blade 15, and is configured to be capable of storing a liquid. The first drain port 14 communicates the first liquid storage hole 13 with the outside of the casing 16. The liquid flowing into the first liquid storage hole 13 passes through the first drain port 14 and is discharged out of the casing 16. The first liquid storage hole 13 and the first drain port 14 correspond to a first drain hole.

  The discharge portion 16D has an inlet surface 16f located downstream of the intermediate portion 16C and extending downstream from the inclined surface 16e, and a discharge surface 16g that forms a discharge passage 12b together with the impeller body 10A described later. The inlet diameter of the gas inlet 16 h formed by the inlet face 16 f is smaller than the outer diameter of the motor 2.

  The motor 2 includes a motor casing, a stator, and a rotor. A cylindrical gap 16i is formed between the outer peripheral surface 2A of the motor 2 and the inner peripheral surface 16e of the motor housing 16B. As shown in FIG. 2, a plurality of first guide blades 15 are provided on the outer peripheral surface 2A of the motor 2 along the circumferential direction. Therefore, the plurality of first guide blades 15 are located in the gap 16i. Each first guide blade 15 is curved, and is configured to give a swirling component to the working fluid passing through the gap 16i.

  The rotating shaft 11 extends in the upstream and downstream directions, is fixed to the rotor of the motor 2, and rotates together with the rotor.

  The impeller 10 is a centrifugal fan, and is fixed to the rotation shaft 11 near a position corresponding to the discharge unit 16D. The impeller 10 includes an impeller body 10A and a plurality of blades 12 provided at equal intervals in a circumferential direction. A discharge path 12b is formed by the impeller body 10A and the discharge section 16D.

  In such a compressor 1, the plurality of impellers 10 rotate by driving the motor 2 to rotate the rotor. By the rotation of the plurality of impellers 10, the working fluid of the gas-liquid mixture flows in from the suction port (not shown), is accelerated, and pressurized, and passes through the gap 16i as shown by the arrow A1. When the working fluid passes through the gap 16i, the working fluid passes through the plurality of first guide blades 15 to give a swirling component, and swirls as indicated by an arrow A2.

  The gas-liquid of the working fluid is separated by the centrifugal force due to the turning, and the liquid component having a density higher than the gas moves outward, and when the working fluid passes through the intermediate portion 16C, the liquid component is removed from the first liquid storage hole. 13 flows. The liquid flowing into the first liquid storage hole 13 is discharged to the outside of the casing 16 through the first drain port 14 as shown by an arrow A3.

  On the other hand, the working fluid that has passed through the inclined surface 16e passes through the inlet 16h, is compressed by the impeller 10, and is discharged through the discharge path 12b as indicated by an arrow A4.

  According to the compressor 1 described above, the first guide impeller 15 configured to give a swirl component to the working fluid flowing toward the impeller 10 through the gap 16i by the rotation of the impeller 10 is provided in the gap 16i. The casing 16 has a first liquid storage hole that opens toward a portion of the through space 16a located between the impeller 10 and the first guide blade 15, and that discharges a liquid in the working fluid. 13 and a first drain port 14 are formed.

  According to such a configuration, gas-liquid of the working fluid is separated by the swirling component given to the working fluid by the first guide blade 15, and the separated liquid flows into the first liquid-storing hole 13, and the first drain is discharged. The liquid is discharged from the liquid port 14 to the outside of the casing 16. As described above, the liquid component contained in the working fluid can be efficiently removed, the adhesion of the liquid component to the blades 12 of the impeller 10 can be suppressed, and the efficiency is reduced due to an increase in the axial power of the impeller 10. Can be suppressed. Further, it is possible to suppress adhesion of liquid components to the blade 12 and the ejection surface 16g of the ejection portion 16D. Therefore, the flow path of the working fluid can be suppressed from being narrowed, and the compressor 1 can be operated without reducing the operating range of the impeller 10. Further, since no auxiliary machine for capturing the liquid component is required, the compressor 1 can be downsized.

  On the other hand, in the conventional compressor 3 shown in FIG. 3, the liquid component contained in the working fluid adheres to the blades 12 of the impeller 10 and the discharge surface 16 g of the casing 16. As a result, the shaft power of the impeller 10 increases, and the efficiency of the compressor 3 decreases. Further, the droplets adhering to the blades 12 and the discharge surface 16g narrow the flow path of the working fluid, thereby reducing the working range, generating unstable fluid force, and reducing the thickness of the blades 12 due to erosion. However, according to the compressor 1 of the present embodiment, these problems of the conventional compressor 3 can be solved.

  Further, since the outer diameter of the motor 2 is configured to be larger than the inlet diameter of the inflow port 16h, the working fluid flows to the impeller 10 through the outer periphery of the motor 2. Thereby, the motor 2 can be cooled by the working fluid, and the motor 2 can be efficiently rotated.

  Since the first drainage hole is constituted by the first drainage hole 13 and the first drainage port 14, the liquid is temporarily stored in the first drainage hole 13. Since the fluid is discharged from the first drain port 14 to the outside of the casing 16, the working fluid can be efficiently discharged.

  Next, a compressor 21 according to a second embodiment of the present invention will be described with reference to FIG. The same components as those of the compressor 1 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different configurations will be described.

  FIG. 4 shows only a left half of a cross-sectional view of a main part of a compressor 21 according to the second embodiment.

  As shown in FIG. 4, in the compressor 21 of the present embodiment, the second liquid storage hole 17 and the second drain port 18 are formed in the intermediate portion 16C. The second liquid storage hole 17 opens toward the through space 16a on the downstream side of the flow of the working fluid from the position where the first liquid storage hole 13 is formed, and is configured to be capable of storing the liquid. I have. The second drain port 18 communicates the second liquid storage hole 17 with the outside of the casing 16. The liquid flowing into the second liquid storage hole 17 passes through the second drain port 18 and is discharged out of the casing 16. The second liquid storage hole 17 and the second drain port 18 correspond to a second drain hole.

  In the present embodiment, after passing through the first liquid storage hole 13, a liquid component flows into the second liquid storage hole 17 from the working fluid swirling as shown by the arrow A <b> 5, and flows into the second liquid storage hole 17. The inflowing liquid is discharged out of the casing 16 through the second drainage port 18 as shown by an arrow A6.

  As described above, according to the compressor 21 according to the present embodiment, the liquid in the working fluid can be further discharged to the outside of the casing 16 by the second liquid storage hole 17 and the second drain port 18. . Therefore, the adhesion of the liquid component to the blades 12 of the impeller 10 can be further suppressed, and a decrease in efficiency due to an increase in the shaft power of the impeller 10 can be suppressed. In addition, it is possible to further suppress the adhesion of the liquid to the discharge surface 16g of the blade 12 and the discharge portion 16D, to suppress the flow path of the working fluid from being narrowed, and to reduce the compression without reducing the operation range of the impeller 10. Machine 21 can be operated.

  Further, since the diameter of the through space 16a is reduced by the inclined surface 16e, the swirling force of the working fluid can be amplified, and separation of gas-liquid in the working fluid can be promoted. Thereby, the liquid component contained in the working fluid can be efficiently removed, and the adhesion of the liquid component to the blades 12 of the impeller 10 can be further suppressed.

  Next, a compressor 31 according to a third embodiment of the present invention will be described with reference to FIG. The same components as those of the compressor 1 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different configurations will be described.

  FIG. 5 shows only a left half of a sectional view of a main part of a compressor 31 according to the third embodiment.

  As shown in FIG. 5, in the compressor 31 of the present embodiment, the casing 16 is provided with a plurality of second guide blades 19. The second guide blades 19 are provided at substantially equal intervals in the circumferential direction toward the rotation shaft 11 with respect to the inlet face 16f. Each second guide blade 19 has a plate shape and is provided in parallel with the upstream and downstream directions.

  As described above, according to the compressor 31 according to the present embodiment, since the swirling component of the working fluid given by the first guide blade 15 can be reduced by each of the second guide blades 19, the impeller 10 In addition, the working fluid can be smoothly transferred from the vertical flow to the horizontal flow, and a decrease in the efficiency of the impeller 10 can be suppressed. Other effects are the same as those of the compressor 1 of the first embodiment.

  Next, a compressor 41 according to a fourth embodiment of the present invention will be described with reference to FIG. The same components as those of the compressors 1, 21, and 31 according to the first to third embodiments are denoted by the same reference numerals, and description thereof will be omitted. Only different configurations will be described.

  FIG. 6 shows only a left half of a cross-sectional view of a main part of a compressor 41 according to a fourth embodiment.

  As shown in FIG. 6, the compressor 41 according to the present embodiment includes, in addition to the configuration of the compressor 1 according to the first embodiment, a second part in the intermediate portion 16C, similarly to the compressor 21 according to the second embodiment. A liquid storage hole 17 and a second drain port 18 are formed, and a plurality of second guide blades 19 are provided in the casing 16 similarly to the compressor 31 of the third embodiment.

  Therefore, according to the compressor 41 according to the present embodiment, the liquid contained in the working fluid is supplied to the first liquid storage hole 13 and the first drain port 14, the second liquid storage hole 17, and the second drain. It can be efficiently removed at the port 18 and the compressor 41 can be operated without reducing the efficiency and operating range of the impeller 10.

  Note that the present invention is not limited to the above-described embodiment. A person skilled in the art can make various additions and changes without departing from the scope of the present invention.

  For example, in the above embodiment, the plurality of first guide blades 15 are provided on the outer peripheral surface 2A of the motor 2, but may be provided on the inner peripheral surface 16e of the motor housing 16B of the casing 16. In the above embodiment, the impeller 10 is a centrifugal fan, but may be an axial fan or a mixed flow fan.

DESCRIPTION OF SYMBOLS 1, 21, 31, 41 Compressor, 2 motors, 10 impellers, 11 rotation shafts, 12 blades, 13 first liquid-storing holes, 14 first drainage ports, 15 first guide blades, 16 casing, 17 second Liquid storage hole, 18 second drain port, 19 second guide vane

Claims (6)

A cylindrical casing forming a space;
A motor provided in the space of the casing with a gap between the casing,
A rotating shaft that extends downstream from the motor and outputs a rotational driving force of the motor;
Downstream of the motor, an impeller fixed to the rotating shaft and compressing a working fluid,
A first guide blade provided in the gap, and configured to give a swirl component to a working fluid that passes through the gap and moves toward the impeller by rotation of the impeller,
The casing has a first drain hole that opens toward a portion of the space that is located between the impeller and the first guide blade and that discharges a liquid component of a working fluid. A compressor. The casing forms an inflow port serving as an inlet of a working fluid to the impeller,
The outer diameter of the motor compressor according to claim 1, characterized in that it is configured larger than the inlet diameter of the inlet.   The casing has a second drain hole that opens toward the space downstream of the flow of the working fluid from a position where the first drain hole is formed, and that discharges a liquid component of the working fluid. The compressor according to claim 1, wherein the compressor is formed. The casing forms an inflow port serving as an inlet of a working fluid to the impeller,
The outer diameter of the motor is configured to be larger than the inlet diameter of the inflow port,
An inner diameter of a portion that houses the motor in the casing is configured to be larger than the inlet diameter of the inflow port, and the casing is inclined such that it approaches the rotation axis from the portion that houses the motor toward the inflow port. The compressor according to claim 3, having a surface.   The first drain hole and the second drain hole are respectively a liquid storage hole for storing the liquid of the working fluid, and a drain port for discharging the liquid stored in the liquid storage hole to the outside of the casing. The compressor according to claim 3, wherein the compressor is configured by:   The second guide vane for reducing a swirling component of the working fluid is provided at an inflow portion of the casing serving as an inlet of the working fluid to the impeller, wherein the second guide vane is provided. The compressor according to any one of claims 5 to 10.

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