JP6840693B2 - Compressor - Google Patents

Description

The present invention relates to a compressor.

In recent years, with the increase in demand for fossil fuels and the development of mining technology, development is shifting from conventional gas fields to unconventional gas fields. Therefore, it is necessary to install the compressor in a harsh environment such as deep water or directly under a gas field.
In deep water, a method (subsea compressor) of installing a compressor on the seabed of several hundred meters and pumping natural gas from the natural gas reservoir in the ground is being studied.

In addition, under the gas field, a method has been proposed in which a compressor is put inside a gas well several thousand meters underground, and natural gas is compressed at the bottom of the well and sent out to the ground. A compressor (downhole compressor) for that purpose has been proposed. ) Is being researched and developed.

At the beginning of the development of the gas field, the underground pressure is high, but as the natural gas is collected, the internal pressure decreases. While the underground pressure in the gas field is high, natural gas can be self-injected to the ground, but when the pressure drops below the limit, natural gas cannot be self-injected. Therefore, in the past, gas wells with reduced pressure were considered to be depleted.

However, even after the underground pressure has dropped to a level insufficient for self-injection of natural gas, a considerable amount of natural gas still remains inside the gas field. Therefore, it is considered possible to restore the production capacity of the gas field by applying a downhole compressor to boost the pressure directly under the gas field.

Since the subsea compressor and downhole compressor described above are installed at the bottom of the gas field or directly under the gas field, the operating environment is extremely harsh. For example, an operating environment in which the working fluid of a compressor, which is generally used in gas fields that produce natural gas, contains not only natural gas but also water and liquids containing light liquid hydrocarbons called condensate ( It is characterized by being under a wet gas environment). Further, since the compressor operated in the downhaul environment is exposed to high temperature conditions, poor cooling of the motor becomes a problem. In the prior art, a method of guiding wet gas to a motor as it is and cooling it has been common.

JP-A-2017-110517

However, as described below, a motor operated in a downhaul environment has a very high rotation speed and therefore has a large pressure loss, and cannot guide sufficient gas to the air gap (gap between the rotor and the stator).

FIG. 7 is a vertical cross-sectional view of the conventional compressor 201.
The impeller 217 has blades 216.
The working fluid sucked from the suction port 211i by the rotation of the impeller 217 by the motor 215 is accelerated and boosted by the rotation action of the impeller 217, and is guided to the downstream 211u.

When the compressor 201 operates in the operating environment of the wet gas 101 mixed with liquid, the wet gas 101 mixed with gas and liquid passes through the air gap 214 between the rotor 212 and the stator 213 inside the motor 215 and is a heating element. A rotor 212 and a stator 213 are cooled at the same time. However, the motor 15 operated in the downhaul environment has a very high rotation speed because the wet gas 101 needs to be greatly boosted. Therefore, the pressure loss of the wet gas 101 is large, and it is not possible to sufficiently guide the wet gas 101 to the air gap 14, and insufficient cooling of the rotor 212 is a problem.

Patent Document 1 is mentioned as relating to a structure for improving the cooling efficiency of the rotor 212 of a general compressor 201.
The present invention was devised in view of the above circumstances, and is a compressor that separates the inflowing wet gas into liquid and gas in an operating environment in which wet gas mixed with liquid is pressurized to improve the cooling efficiency of the rotor. The purpose is to provide.

In order to solve the above problems, the compressor of the present invention is provided in the lower part of the gas well provided in the upper part of the gas field and forms an outer shell, and the inflowing fluid is placed on the central side liquid and the outer peripheral side. A separator that separates the fluid into a gas, an impeller that rotates the fluid and compresses the fluid, a motor that is installed upstream of the impeller, and a rotor that is rotationally driven by the motor are provided inside the rotor. A flow path through which the liquid passes and an air gap provided between the casing and the stator of the motor are provided , and the gas passes through the gap between the air gap and the rotor and the stator. Is flowing downstream .

According to the present invention, it is possible to provide a compressor that separates the inflowing wet gas into liquid and gas in an operating environment in which wet gas mixed with liquid is pressurized to improve the cooling efficiency of the rotor.

The schematic cross-sectional view which shows the installation state of the compressor which concerns on 1st Embodiment of this invention. The vertical sectional view of the compressor which concerns on 1st Embodiment of this invention. The vertical sectional view of the compressor of the modification 1 of 1st Embodiment. (A) is a vertical sectional view of the compressor of the modified example 2 of the first embodiment, and (b) is a schematic view of the guide vane viewed from the outside. (A) is a vertical sectional view of the compressor according to the second embodiment of the present invention, (b) is a schematic view of the upstream guide vane seen from the outside, and (c) is a schematic view of the downstream guide vane seen from the outside. Figure. (A) is a vertical sectional view of a compressor according to a modified example of the second embodiment of the present invention, (b) is a schematic view of an upstream guide vane viewed from the outside, and (c) is a downstream guide vane viewed from the outside. Schematic diagram seen. Longitudinal section of a conventional compressor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
The present invention particularly relates to a compressor used in a gas field or the like that produces natural gas.

Specifically, according to the present invention, in a compressor operating in an operating environment in which a fluid mixed with liquid is pressurized, the fluid flowing into the compressor is separated into a liquid and a gas, and the separated liquid is separated into the inside of the rotor. This leads to the improvement of the cooling efficiency of the rotor.

<< First Embodiment >>
FIG. 1 is a schematic cross-sectional view showing an installed state of the compressor 1 according to the first embodiment of the present invention.
At the beginning of excavating the gas well Gi in the gas field Gt, the pressure underground in the gas field Gt is high, and natural gas (101) can be self-injected to the ground through the gas well Gi without installing the compressor 1. However, as time passes, the underground pressure drops below the limit of self-injection, and natural gas cannot be self-injected.

However, even after the underground pressure drops below the limit, a considerable amount of natural gas (101) still remains inside the gas field Gt.
Therefore, as shown in FIG. 1, the compressor 1 of the first embodiment is installed directly under the gas field Gt and boosted to recover the production capacity of the gas field Gt.

FIG. 2 is a vertical cross-sectional view of the compressor 1 according to the first embodiment of the present invention.
A turbo type compressor is adopted as the compressor 1 of the first embodiment.

The outer shell of the compressor 1 is formed by the casing 11.
The compressor 1 is provided with a separator 19, a motor 15, and an impeller 17 in this order from the suction port 11i toward the downstream side (upper side in FIG. 2) inside the casing 11.

That is, the separator 19 is provided on the upstream side of the motor 15 and the impeller 17.
The separator 19 separates the wet gas 101 (arrow α11 in FIG. 2) flowing in from the suction port 11i into the liquid 102 on the central side and the gas 103 on the outer peripheral side.

The motor 15 has a rotor 12 and a stator 13. The rotor 12 is provided with a magnet (not shown) facing the stator 13.
An air gap 14 which is a gap is provided between the rotor 12 and the stator 13. A gap 11g, which is a gap, is provided between the stator 13 and the casing 11.

A cooling flow path 18 having a through hole is provided in the center of the rotor 12.
The impeller 17 has a blade 16 that boosts the gas 103 by rotating. The blades 16 are held by a rotor 12 that is rotationally driven by a motor 15, and are provided at substantially equal intervals in the circumferential direction of the impeller 17.

<Operation of compressor 1>
The operation of the compressor 1 will be described.

As shown in FIG. 2, the wet gas 101 mixed with gas and liquid flowing in from the suction port 11i (α11 in FIG. 2) is separated into the liquid 102 and the gas 103 at the separator 19. For example, the liquid 102 contained in the wet gas 101 is guided to the vicinity of the cooling flow path 18 at the center of the rotor 12 by using a membrane separation technique or the like. On the other hand, the gas 103 contained in the wet gas 101 is guided toward the stator 13, the air gap 14, and the gap 11g.

In this way, the gas 103 flows through the air gap 14 together with the gap 11 g (α13 in FIG. 2).
Therefore, even if the pressure loss of the gas 103 is large and sufficient gas 103 is not guided to the air gap 14, the rotor 12 is surely cooled by the liquid 102 (α12 in FIG. 2) passing through the cooling flow path 18.

The gas 103 that has passed through the gap 11 g and the air gap 14 flows into the impeller 17 and is transported downstream by the impeller 17 (α15 in FIG. 2).

<Modification example 1>
FIG. 3 is a vertical cross-sectional view of the compressor 1A of the first modification of the first embodiment.
In the compressor 1A of the first modification, the pump 20 is integrally formed downstream of the impeller 17. The suction port 20i of the pump 20 communicates with the cooling flow path 18 of the rotor 12.

In the compressor 1A, a pump 20 having an impeller 20h installed on the same rotor 12 as the impeller 17 is provided on the back surface (downstream side) of the impeller 17. As a result, the liquid 102 passing through the cooling flow path 18 of the rotor 12 is pumped up by the rotation of the impeller 20h of the pump 20 (arrow α22 in FIG. 3), and the transportation of the liquid 102 in the cooling flow path 18 is promoted (). Arrow α21 in FIG. 3). As a result, the liquid 102 is efficiently transported inside the cooling flow path 18, and the cooling of the rotor 12 is promoted.

<Modification 2>
FIG. 4A is a vertical cross-sectional view of the compressor 1B of the modified example 2 of the first embodiment, and FIG. 4B is a schematic view of the guide vane 22 viewed from the outside.
In the compressor 1B of the second modification, a blade-shaped guide vane 22 is provided on the downstream side of the impeller 17. The guide vane 22 guides the separated gas 103 upward.

A discharge hole 22k is formed inside the guide vane 22, and a discharge flow path 21 is installed in the casing 11 in succession to the discharge hole 22k.
With this configuration, the liquid 102 separated by the separator 19 flows into the pump 20 through the cooling flow path 18 at the center of the rotor 12 (arrow α31 in FIG. 4). The liquid 102 that has flowed into the pump 20 is discharged through the discharge hole 22k and the discharge flow path 21 inside the guide vane 22 (arrow α32 in FIG. 4).

On the other hand, the gas 103 separated by the separator 19 passes through the air gap 14 between the rotor 12 and the stator 13 (arrow α33 in FIG. 4) and also passes through the gap 11g between the stator 13 and the casing 11. (Arrow α34 in FIG. 4) flows into the impeller 17. Then, the gas 103 is boosted by the impeller 17 (arrow α35 in FIG. 4) and flows downstream (arrow α36 in FIG. 4).

By installing the discharge hole 22k inside the guide vane 22 provided on the downstream side of the impeller 17 and installing the discharge flow path 21 in the casing 11, the liquid 102 transported by the pump 20 is discharged to the outside of the casing 11. Will be done. Further, the turning component of the gas 103 boosted by the impeller 17 is removed by the guide vane 22. Therefore, the boosting energy of the gas 103 can be efficiently guided to the gas 103 downstream of the compressor 1.

According to the above configuration, the liquid 102 that cools the rotor 12 can be separated by using the separator 19.
Further, in the compressor 1 operating in an operating environment in which the liquid 102 of the liquid component is mixed, the wet gas 101 flowing into the compressor 1 is separated into the liquid 102 and the gas 103. The rotor 12 can be cooled by passing the liquid 102 separated from the wet gas 101 through the cooling flow path 18.

Therefore, the liquid 102 of the separated liquid can be guided to the cooling flow path 18 inside the rotor 12 to improve the cooling efficiency of the rotor 12.
Therefore, for example, in the compressor 1 that operates in a downhaul environment or is exposed to high temperature conditions, the cooling efficiency of the rotor 12 can be improved without using an external cooling device or the like.

<< Second Embodiment >>
FIG. 5A is a vertical cross-sectional view of the compressor 2 according to the second embodiment of the present invention, and FIG. 5B is a schematic view of the upstream guide vane 22a as viewed from the outside. FIG. (C) is a schematic view of the downstream guide vane 22b viewed from the outside.

As shown in FIG. 5A, the compressor 2 of the second embodiment is provided with the separator 29 on the downstream side of the impeller 17.
As the compressor 2 of the second embodiment, a turbo type compressor is adopted.

In the compressor 2, an upstream guide vane 22a, a motor 15, an impeller 17, a tank 23, a downstream guide vane 22b, and a separator 29 are installed inside the casing 11.
The motor 15 has a rotor 12 and a stator 13. A blade-shaped upstream guide vane 22a is installed upstream of the motor 15.

As shown in FIG. 5B, a discharge hole 22a1 is formed inside the guide vane 22a on the upstream side of the casing 11 and communicates with the discharge flow path 21 of the through hole formed in the casing 11 and communicates with the outside. ing.
The compressor 2 has an impeller 17 which is held by a rotor 12 which is rotationally driven by a motor 15 and has vanes 16 which are provided at substantially equal intervals in the circumferential direction of the impeller 17.

A separator 29 for gas-liquid separation is installed downstream of the impeller 17 (upper side of FIG. 5A). The separator 29 separates the wet gas 101 on the upstream side (arrow α46 in FIG. 5A) and the liquid 102 on the downstream side (arrow α47 in FIG. 5A).

Upstream of the separator 29, a tank 23 having a substantially truncated cone-shaped storage portion for storing the liquid 102 separated by the separator 29 is provided.
A blade-shaped downstream guide vane 22b is provided on the upstream side of the separator 29. As a result, the swirling component of the wet gas 101 formed by the impeller 17 can be eliminated, and the pressure to be sent to the separator 29 can be effectively applied to the wet gas 101.

<Operation of compressor 2>
The operation of the compressor 2 will be described.
In the compressor 2, the wet gas 101 mixed with gas and liquid is boosted by the rotation of the blade 16 of the impeller 17 and guided to the downstream side (upper side of FIG. 5A) (arrows α41 to α44 of FIG. 5A). ).

Specifically, the wet gas 101 flowing in from the suction port 11i of the casing 11 passes between the guide vanes 22a (arrow α41 in FIG. 5A). The wet gas 101 passes through the gap 11g between the stator 13 and the casing 11 (arrow α42 in FIG. 5A) and the air gap 14 between the rotor 12 and the stator 13. (Arrow α43 in FIG. 5A).

The wet gas 101 that has passed through the gap 11g and the wet gas 101 that has passed through the air gap 14 flow into the impeller 17 (arrow α44 in FIG. 5A) and are boosted.
The wet gas 101 boosted by the impeller 17 passes between the downstream guide vanes 22b and flows into the separator 29 (arrow α45 in FIG. 5A). At this time, the swirling component of the wet gas 101 emitted from the impeller 17 is removed by the downstream guide vane 22b.

Then, in the separator 29, the wet gas 101 is separated into the liquid 102 and the gas 103. The liquid 102 separated in the separator 29 using, for example, a membrane separation technique, a corelesser, a mesh demister, or the like is temporarily stored in the tank 23 (arrow α47 in FIG. 5A).

After that, the liquid 102 of the tank 23 is guided to the cooling flow path 18 provided in the center of the rotor 12 (arrow α48 in FIG. 5A), and the discharge hole 22a1 of the upstream guide vane 22a and the discharge flow path of the casing 11 It flows through 21 and is discharged to the outside of the compressor 1 (arrow α49a in FIG. 5A).

On the other hand, the gas 103 separated by the separator 29 is guided downstream of the compressor 2 (arrow α46 in FIG. 5A).
According to the above configuration, the tank 23 is provided on the upstream side of the separator 29, and the separator 29 separates the liquid 102 on the upstream side of the wet gas 101 and the gas 103 on the downstream side of the wet gas 101. As a result, the liquid 102 before flowing into the cooling flow path 18 can be stored in the tank 23.

Further, by providing the upstream guide vane 22a in the vicinity of the discharge flow path 21 in the longitudinal direction of the casing 11, the liquid 102 can be smoothly discharged from the discharge flow path 21 through the discharge hole 22a1 of the upstream guide vane 22a.
Further, the separator 29 separates the liquid 102 on the upstream side of the wet gas 101 and the gas 103 on the downstream side of the wet gas 101. As a result, the liquid 102 can be used for cooling the rotor 12.

Therefore, even if the pressure loss of the wet gas 101 is large and sufficient wet gas 101 is not guided to the air gap 14, the rotor 12 is surely cooled by the liquid 102 passing through the cooling flow path 18.

<Modification example>
FIG. 6A is a vertical sectional view of the compressor 2H according to a modified example of the second embodiment of the present invention, FIG. 6B is a schematic view of the upstream guide vane 22a viewed from the outside, and FIG. 6C is a schematic view. It is a schematic diagram which looked at the downstream side guide vane 22b from the outside.
The compressor 2H of the modified example has a configuration in which a pump 30 is provided downstream of the cooling flow path 18 to promote the flow of the liquid 102 passing through the cooling flow path 18.

Other configurations are the same as those of the second embodiment.
The compressor 2H of the modified example has an impeller 17 at the other end of the rotor 12, which is the same as one impeller 17, that is, at the downstream portion of the cooling flow path 18, so that the flow path is continuous with the cooling flow path 18. It is installed so as to face the.

Further, an upstream guide vane 22a is installed on the outer peripheral side of the pump 30 in order to eliminate the swirling component of the liquid 102. Inside the upstream guide vane 22a, a discharge hole 22a1 communicating with the discharge flow path 21 of the casing 11 is formed. The 102 that has flowed through the cooling flow path 18 flows through the discharge hole 22a1 of the upstream guide vane 22a and the discharge flow path 21 of the casing 11 and is discharged.

As a result, by rotationally driving the rotor 12 with the motor 15, the impeller 30h of the pump 30 rotates, and the flow of the liquid 102 passing through the cooling flow path 18 can be controlled.
The pump 30 can efficiently transport the liquid 102 passing through the cooling flow path 18 provided at the center of the rotor 12 to promote the cooling of the rotor 12. Then, the liquid 102 transported by the pump 30 passes through the discharge hole 22a1 located on the outer peripheral side of the pump 30 and the discharge flow path 21 and is discharged to the outside of the casing 11.

According to the modified example, the liquid 102 is transported by the pump 30 and can efficiently flow through the cooling flow path 18. Therefore, the rotor 12 can be cooled more effectively.

<< Other Embodiments >>
1. 1. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

1, 1A, 1B, 2, 2H Compressor 11 Casing 12 Rotor 15 Motor 16 Blades 17 Impeller 18 Cooling flow path (flow path)
19, 29 Separator 20, 30 Pump 21 Discharge flow path (first discharge hole)
22a 2nd guide vane 22b 1st guide vane 22a1, 22k Discharge hole (2nd discharge hole)
23 Tank 101 Wet gas (fluid)
102 liquid 103 gas (gas)

Claims (7)

Located at the bottom of the gas well at the top of the gas field,
And,
The casing that forms the outer shell and
A separator that separates the inflowing fluid into a liquid on the center side and a gas on the outer circumference side,
An impeller that rotates and compresses the fluid,
The motor installed upstream of the impeller and
A flow path provided inside a rotor that is rotationally driven by the motor and through which the liquid passes, and
An air gap provided between the casing and the stator of the motor is provided .
The gas compressor, characterized in that said an air gap, Ru flows downstream through the gap between the rotor and the stator. In the compressor according to claim 1,
A compressor including a pump driven by the same rotor shared with the impeller and transporting the liquid through the flow path. In the compressor according to claim 1,
The separator is a compressor characterized in that the liquid is separated so as to be guided to the flow path. In the compressor according to claim 1,
The separator is a compressor characterized by separating the liquid on the upstream side of the fluid and separating the gas on the downstream side of the fluid. In the compressor according to claim 1,
A tank is provided on the upstream side of the separator.
The separator is a compressor characterized by separating the liquid on the upstream side of the fluid and separating the gas on the downstream side of the fluid. A separator that separates the inflowing fluid into a liquid and a gas,
An impeller that rotates and compresses the fluid,
The motor installed upstream of the impeller and
It is provided inside a rotor that is rotationally driven by the motor, and is provided with a flow path through which the liquid passes.
The separator is arranged on the downstream side of the impeller.
A compressor characterized in that a first guide vane for guiding the fluid to the downstream side is provided on the upstream side of the separator. In the compressor according to claim 1 ,
Communicates with previous SL channel, compressor, characterized in that it comprises a second guide vane having a second discharge hole for discharging the liquid to the outside of the casing through the first discharge hole of the casing.

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