JP5633251B2 - Oxygen compressor sealing device - Google Patents

Description

  The present invention relates to a sealing device for an oxygen compressor.

  Centrifugal compressors are widely used as means for compressing and pressurizing various gases including air, carbon dioxide, and nitrogen.

  In an oxygen compressor that pressurizes oxygen with high combustion resistance, a labyrinth-type shaft seal device is provided between an impeller rotating shaft and a stationary housing portion through which the impeller rotating shaft is inserted. Leaks out of the part.

  As a shaft seal device used for an oxygen compressor, a first labyrinth seal portion, a second labyrinth seal portion, a third labyrinth seal portion, and a fourth labyrinth are provided between an inner peripheral surface of a housing portion and an outer peripheral surface of an impeller rotary shaft. The seal portion, the fifth labyrinth seal portion, and the sixth labyrinth seal portion are provided adjacent to each other in the axial direction of the impeller rotating shaft from the high pressure side (impeller side) to the low pressure side (anti-impeller side). One in which a pressure chamber is formed between the labyrinth seal portions is known (for example, see Patent Document 1).

  A pressure chamber between the first labyrinth seal portion and the second labyrinth seal portion, a pressure chamber between the second labyrinth seal portion and the third labyrinth seal portion, and a third labyrinth seal portion and a fourth labyrinth seal portion A process gas recovery line is connected to the pressure chamber between the two. This process gas recovery line plays a role of recovering oxygen when the pressure increased by the rotation of the impeller enters the high pressure side pressure chamber through the back side of the impeller.

  An atmospheric purge line is connected to the pressure chamber between the fourth labyrinth seal portion and the fifth labyrinth seal portion, and a seal is provided to the pressure chamber between the fifth labyrinth seal portion and the sixth labyrinth seal portion. Gas supply line is connected. The seal gas supply line plays a role of supplying nitrogen to the pressure chamber on the lowest pressure side so that oxygen does not leak out of the housing portion. The atmospheric purge line passes through the pressure chamber which is not fully recovered in the pressure chamber on the high pressure side and enters the pressure chamber between the fourth labyrinth seal portion and the fifth labyrinth seal portion, and the pressure chamber on the lowest pressure side. The nitrogen mixed gas that has entered the pressure chamber between the fourth labyrinth seal portion and the fifth labyrinth seal portion plays a role of releasing air into the atmosphere.

Japanese Unexamined Patent Publication No. 2007-247466, paragraphs 0006-0011, FIG.

  In a compressor in which oxygen is supplied from a plurality of oxygen generation facilities, the compressor is operated in a case where all the oxygen generation facilities are operated in parallel or in a case where only one oxygen generation facility is operated independently. The oxygen suction pressure varies greatly. For example, when all the oxygen generation facilities are operating, even if the oxygen suction pressure of the compressor is 25 kPa (G), when only one oxygen generation facility is operating, The oxygen suction pressure becomes 5 kPa (G) [where (G) means a gauge pressure].

  In the above-described shaft seal device, when the amount of nitrogen supplied to the pressure chamber on the lowest pressure side with respect to the oxygen suction pressure of the compressor is excessive, the nitrogen reaches the pressure chamber on the high pressure side. There is a concern that nitrogen is mixed in oxygen recovered from the pressure chamber and returned to the compressor, and as a result, the purity of oxygen pressurized by the compressor is lowered.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an oxygen compressor sealing device that can suppress a decrease in oxygen purity.

In order to achieve the above object, a sealing device for an oxygen compressor according to claim 1,
Attached to the compressor from which oxygen is supplied from the oxygen generation facility to the suction port via the oxygen suction pipe, a recovery pocket, a discharge pocket, in order from the high pressure side to the low pressure side in the housing part through which the impeller rotary shaft is inserted, And a labyrinth-type shaft seal device body formed with a sealing pocket,
The oxygen suction pipe is connected to the recovery pocket of the shaft seal device body through an oxygen recovery pipe,
The discharge pocket of the shaft seal device body is connected to a discharge pipe whose downstream end is open to the atmosphere,
Connect the seal gas supply piping connected to the seal gas supply source to the seal pocket of the shaft seal device body,
Incorporated into the oxygen recovery pipe into the flow rate adjustment valve,
A pressure sensor for detecting the internal pressure of the recovery pocket is provided;
A controller is provided for adjusting the opening of the flow rate adjustment valve so that the detected value of the pressure sensor exceeds a preset lower limit of the internal pressure, thereby reducing or increasing the amount of oxygen flowing through the oxygen recovery pipe. Yes.

The oxygen compressor sealing device according to claim 2,
Oxygen boosted by the compressor is attached to the latter stage compressor that is supplied to the suction port via the oxygen supply pipe, and is sequentially recovered from the high pressure side to the low pressure side in the housing portion through which the impeller rotary shaft is inserted. A labyrinth-type rear shaft sealing device body having a pocket, a discharge pocket, and a sealing pocket,
The recovery pocket of the shaft seal device main body is communicated with the recovery pocket of the main shaft seal device body,
The discharge pocket of the shaft seal device main body is communicated with the discharge pocket of the shaft seal device main body,
The sealing pocket of the shaft sealing device main body is communicated with the sealing pocket of the rear shaft sealing device main body.

  According to the sealing device for an oxygen compressor of the present invention, the following excellent effects can be obtained.

  (1) In the oxygen compressor sealing device according to claim 1, the flow rate of the oxygen recovery pipe is set so that the internal pressure of the recovery pocket of the shaft seal device main body attached to the compressor exceeds a preset lower limit range of the internal pressure. Since the opening of the regulating valve is adjusted to prevent a decrease in the internal pressure of the recovery pocket, when the oxygen suction pressure in the compressor becomes low, nitrogen does not flow from the discharge pocket to the oxygen suction pipe, and the oxygen purity is reduced. Decline can be suppressed.

  (2) In the oxygen compressor sealing device according to claim 2, the sealing pocket of the main shaft sealing device attached to the rear compressor communicates with the sealing pocket of the main shaft sealing device attached to the compressor. The discharge pocket of the main shaft seal device attached to the compressor communicates with the discharge pocket of the main shaft seal device attached to the compressor, and the recovery pocket of the main shaft seal device attached to the rear compressor is connected to the compressor. Since it communicates with the collection pocket of the attached shaft seal device main body, it is possible to suppress the decrease in oxygen purity in the compressor and the downstream compressor by using one flow rate adjusting valve and one controller.

It is a conceptual diagram which shows an example of the sealing apparatus of the oxygen compressor of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a sealing device for an oxygen compressor according to the present invention, which is intended for a multi-stage turbo compressor.

  A is a labyrinth shaft seal device main body, and the shaft seal device main body A receives oxygen from a plurality of oxygen generation facilities (not shown) through the oxygen suction pipe 10 and the suction port of the compressor casing 2. Is attached to the compressor 1 fed to the compressor.

Between the outer peripheral surface of the impeller rotary shaft 4 and the inner peripheral surface of the housing part 5 through which the impeller rotary shaft 4 is inserted, a first labyrinth seal portion 9a, a second labyrinth seal portion 9b, and a third labyrinth seal portion. 9c and the fourth labyrinth seal portion 9d are provided at intervals in the axial direction of the impeller rotating shaft 4 from the high pressure side (impeller side) to the low pressure side (anti-impeller side), and the first labyrinth seal portion A recovery pocket 6 is formed between 9a and the second labyrinth seal portion 9b, a discharge pocket 7 is formed between the second labyrinth seal portion 9b and the third labyrinth seal portion 9c, and the third labyrinth seal portion 9c A sealing pocket 8 is formed between the fourth labyrinth seal portion 9d.
These pockets 6, 7, and 8 correspond to the pressure chambers in Patent Document 1, and the rotation of the electric motor 35 is transmitted to the impeller rotary shaft 4 through a speed increasing mechanism in the gear box 3. .

A basic oxygen recovery pipe 14 whose downstream end communicates with the oxygen suction pipe 10 is connected to the recovery pocket 6 of the shaft seal device main body A.
To the discharge pocket 7 of the shaft seal device main body A, the upstream end of the main air discharge pipe 13 whose downstream end is open to the atmosphere outside the building 12 is connected.
Connected to the sealing pocket 8 of the shaft seal device main body A is the downstream end of the main seal gas feed pipe 11 communicating with the gas tank 36 whose upstream end stores nitrogen as a seal gas.

  As described in paragraph 0008, the oxygen suction pressure of the compressor casing 2 varies, for example, in the range of 5 to 25 kPa (G) depending on the operation status of the oxygen generation facility. Further, the seal gas supply pressure from the gas tank to the main seal gas supply pipe 11 is set to 27 kPa (G) so as to be 2 kPa (G) or more higher than the oxygen suction pressure [where (G) is the gauge pressure. It means that].

  B is a rear shaft seal device main body of the labyrinth type, and the rear shaft seal device main body B is supplied with oxygen boosted by the compressor 1 to the suction port of the compressor casing 16 via the oxygen supply pipe 23. It is attached to the latter stage compressor 15 to be fed.

Between the outer peripheral surface of the impeller rotating shaft 17 and the inner peripheral surface of the housing part 18 through which the impeller rotating shaft 17 is inserted, a first labyrinth seal portion 9e, a second labyrinth seal portion 9f, and a third labyrinth seal portion. 9g, the fourth labyrinth seal portion 9h, and the fifth labyrinth seal portion 9i are provided at intervals in the axial direction of the impeller rotary shaft 17 from the high pressure side (impeller side) to the low pressure side (anti-impeller side). Yes, a recovery pocket 19 is formed between the first labyrinth seal portion 9e and the second labyrinth seal portion 9f, and a recovery pocket 20 is formed between the second labyrinth seal portion 9f and the third labyrinth seal portion 9g, A discharge pocket 21 is formed between the third labyrinth seal portion 9g and the fourth labyrinth seal portion 9h, and the fourth labyrinth seal portion 9h and the fifth labyrinth seal. To form a sealed pocket 22 between the 9i.
These pockets 19, 20, 21, and 22 correspond to the pressure chambers in Patent Document 1, and the rotation of the electric motor 35 is transmitted to the impeller rotary shaft 17 through the speed increasing mechanism in the gear box 3. Is done.

An upstream end of an oxygen return pipe 27 communicating with the upstream side of an intercooler (not shown) is connected to the recovery pocket 19 of the rear shaft seal device main body B.
The upstream end of a rear oxygen recovery pipe 26 whose downstream end communicates with the basic oxygen recovery pipe 14 is connected to the recovery pocket 20 of the rear shaft seal device main body B.
The discharge pocket 21 of the latter-stage shaft seal device main body B is connected to the upstream end of a rear-stage air discharge pipe 25 whose downstream end communicates with the basic air-discharge pipe 13.
The downstream end of the rear seal gas supply pipe 24 whose upstream end communicates with the basic seal gas supply pipe 11 is connected to the sealing pocket 22 of the rear shaft seal device main body B.

Therefore,
The internal pressure of the sealing pocket 8 of the shaft seal device main body A attached to the compressor 1 and the internal pressure of the seal pocket 22 of the rear shaft seal device main body B attached to the rear compressor 15 are equal to the internal pressure of the basic seal gas supply pipe 11. Equal,
The internal pressure of the discharge pocket 7 of the shaft seal device main body A attached to the compressor 1 and the internal pressure of the discharge pocket 21 of the rear shaft seal device main body B attached to the rear compressor 15 are theoretically atmospheric pressure [actually, Because of the pressure loss of the main ventilating pipe 13, for example, a pressure of about 5 kPa (G) is exhibited]
The internal pressure of the recovery pocket 6 of the shaft seal device main body A attached to the compressor 1 and the internal pressure of the recovery pocket 20 of the rear shaft seal device main body B attached to the rear compressor 15 are the basic oxygen recovery pipe 14 and the oxygen suction pipe. Equal to 10 internal pressures.

  A characteristic part of the sealing device of the oxygen compressor according to the present invention is that a flow rate adjusting valve 32 is incorporated in the basic oxygen recovery pipe 14 and a pressure sensor 33 for detecting the internal pressure of the recovery pocket 6 of the shaft seal device main body A attached to the compressor 1. And a controller for increasing or decreasing the flow rate of oxygen by transmitting an opening adjustment signal 34 s to the flow rate adjustment valve 32 so that the detected value 33 s of the pressure sensor 33 exceeds a preset lower limit range of the internal pressure. The pressure sensor 33 is attached to a location upstream of the flow rate adjustment valve 32 of the basic oxygen recovery pipe 14.

The upper limit value of the internal pressure lower limit range set in the controller 34 is, for example, 15 kPa (G) which is an intermediate value between the lower limit value [5 kPa (G)] and the upper limit value [25 kPa (G)] of the oxygen suction pressure of the compressor 1. The lower limit value of the inner pressure lower limit range set in the controller 34 is, for example, the lower limit value [5 kPa (G)] of the oxygen suction pressure of the compressor 1 and the upper limit value [15 kPa (G) of the inner pressure lower limit range. ] 10 kPa (G), which is an intermediate value between

  Then, the controller 34 transmits an opening degree adjustment signal 34s to the flow rate adjustment valve 32 so that the detected value 33s of the pressure sensor 33 exceeds the lower limit value [(10 kPa (G)] of the internal pressure lower limit range, and the flow rate adjustment valve. The opening degree of 32 is adjusted, and the function of decreasing or maximizing the oxygen circulation amount in the basic oxygen recovery pipe 14 is provided.

  When the compressor 1 and the downstream compressor 15 are operated to increase the pressure of oxygen delivered from the oxygen generation facility, nitrogen stored as a seal gas in the gas storage tank is always sent to the basic seal gas supply pipe 11. To pay.

Nitrogen flowing through the basic seal gas supply pipe 11 is
Directly flows into the sealing pocket 8 of the shaft seal device main body A attached to the compressor 1,
The latter compressor 15 flows into the sealing pocket 22 of the accompanying latter-stage shaft seal device main body B via the latter-stage seal gas supply pipe 24.

  Part of the oxygen boosted by the compressor 1 leaks into the shaft seal device main body A, and most of the oxygen flowing into the recovery pocket 6 passes through the oxygen suction pipe 10 from the basic oxygen recovery pipe 14 and the pressure before pressure increase. It returns to the suction port of the compressor casing 2 which is the atmosphere.

  The remaining oxygen that has not returned to the suction port of the compressor casing 2 flows into the discharge pocket 7, and this oxygen is supplied to the sealing pocket 8 at a pressure higher than the oxygen suction pressure of the compressor 1. Therefore, it does not leak out from the housing part 5 of the shaft seal device main body A.

  The oxygen that has flowed into the discharge pocket 7 is discharged into the atmosphere along with the nitrogen that has passed through the sealing pocket 8 through the main air discharge pipe 13 whose downstream end is an atmospheric pressure atmosphere.

  Oxygen boosted by the compressor 1 flows into the suction port of the compressor casing 16 of the rear-stage compressor 15 through the oxygen supply pipe 23. Part of the oxygen boosted by the rear-stage compressor 15 leaks into the rear-stage shaft seal body B, and most of the oxygen flowing into the recovery pocket 19 is sent to the intercooler (not shown) via the oxygen return pipe 27. It is.

  The remaining oxygen that has not been sent to the intercooler flows into the recovery pocket 20 of the rear shaft seal body B, but most of the oxygen passes from the rear oxygen recovery pipe 26 and the main oxygen recovery pipe 14 through the oxygen suction pipe 10. It returns to the suction port of the compressor casing 2 which is the pressure atmosphere before the pressure increase.

  The remaining oxygen that has not returned to the suction port of the compressor casing 2 flows into the discharge pocket 21 of the rear shaft seal device main body B. This oxygen is nitrogen in the sealing pocket 22 of the rear shaft seal device main body B. Since it is supplied at a pressure higher than the oxygen suction pressure of the compressor 1, it does not leak out from the housing portion 18 of the rear shaft seal device main body B.

  Then, the oxygen flowing into the discharge pocket 21 is discharged into the atmosphere through the rear air discharge pipe 25 and the main air discharge pipe 13 together with the nitrogen that has passed through the sealing pocket 22.

  When a state in which a plurality of oxygen generation facilities are operated in parallel to a state in which only one oxygen generation facility is operated independently, the oxygen suction pressure of the compressor 1 decreases, and finally the compressor 1 To the actual internal pressure of the discharge pocket 7 of the incidental shaft seal device main body A [presenting a pressure of about 5 kPa (G)].

  When the detected value 33 s of the pressure sensor 33 falls below 10 kPa (G) which is the lower limit value of the internal pressure lower limit range, an opening degree adjustment signal 34 s for narrowing the opening degree is transmitted from the controller 34 to the flow rate adjustment valve 32. When the opening degree of the flow rate adjusting valve 32 is narrowed, oxygen becomes basic oxygen from the recovery pocket 6 of the shaft seal device main body A attached to the compressor 1 and the recovery pocket 20 of the rear shaft seal device main body B attached to the rear compressor 15. It becomes difficult to flow to the recovery pipe 14, and the internal pressure of the recovery pockets 6 and 20 increases.

  The controller 34 continues to transmit an opening degree adjustment signal 34s for narrowing the opening degree to the flow rate adjustment valve 32 until the detected value 33s of the pressure sensor 33 exceeds 10 kPa (G) which is the lower limit value of the inner pressure lower limit range. As a result, nitrogen in the discharge pocket 7 of the shaft seal device main body A attached to the compressor 1 is prevented from flowing into the recovery pocket 6, and the discharge pocket of the rear shaft seal device main body B attached to the rear compressor 15 is prevented. The nitrogen in the gas 21 is prevented from flowing into the recovery pocket 6, so that nitrogen as a seal gas does not flow into the oxygen intake pipe 10 through the basic oxygen recovery pipe 14.

  Thereafter, for example, when shifting from a state where only one oxygen generating facility is operated independently to a state where a plurality of oxygen generating facilities are operated in parallel, the oxygen suction pressure of the compressor 1 increases. The detection value 33 s of the pressure sensor 33 exceeds 15 kPa (G), which is the upper limit value of the inner pressure lower limit range, the internal pressure of the recovery pocket 6 of the shaft seal device main body A attached to the compressor 1, and the latter stage attached to the rear compressor 15. When the internal pressure of the recovery pocket 20 of the shaft seal device main body B sufficiently exceeds the internal pressure of the discharge pocket 7 of the shaft seal device main body A and the internal pressure of the recovery pocket 20 of the rear shaft seal device main body B, the controller 34, an opening adjustment signal 34s for fully opening the opening is transmitted to the flow rate adjustment valve 32, and most of the oxygen flowing into the recovery pockets 6 and 20 passes from the main oxygen recovery pipe 14 through the oxygen intake pipe 10, It returns to the suction port of the compressor casing 2 which is the pressure atmosphere before the pressure increase.

  In the oxygen compressor sealing device shown in FIG. 1, the basic pressure is such that the internal pressures of the recovery pocket 6 of the shaft seal device main body A and the recovery pocket 20 of the rear shaft seal device main body B exceed the preset lower limit range of the internal pressure. Since the opening degree of the flow rate adjustment valve 32 of the oxygen recovery pipe 14 is adjusted to prevent the internal pressure of the recovery pockets 6 and 20 from being lowered, the discharge pockets 7 and 21 when the oxygen suction pressure in the compressor 1 becomes low. From this, nitrogen does not flow into the oxygen suction pipe 10, and a decrease in oxygen purity can be suppressed.

  The sealing pocket 22 of the rear shaft seal device main body B attached to the rear compressor 15 communicates with the sealing pocket 8 of the shaft seal device main body A attached to the compressor 1, and the rear shaft seal device main body attached to the rear compressor 15. The discharge pocket 21 of B communicates with the discharge pocket 7 of the shaft seal device main body A attached to the compressor 1, and the recovery pocket 20 of the rear shaft seal device main body B attached to the rear compressor 15 is attached to the compressor 1. Therefore, it is possible to suppress the decrease in oxygen purity in the compressor 1 and the downstream compressor 15 with one flow rate adjusting valve 32 and one controller 34. .

DESCRIPTION OF SYMBOLS 1 Compressor 4 Impeller rotating shaft 5 Housing part 6 Collection | recovery pocket 7 Discharge pocket 8 Sealing pocket 10 Oxygen intake piping 11 Basic seal gas supply piping (seal gas supply piping)
13 Basic air vent piping (air vent piping)
14 Basic oxygen recovery piping (oxygen recovery piping)
DESCRIPTION OF SYMBOLS 15 Back stage compressor 17 Impeller rotating shaft 18 Housing part 20 Collection | recovery pocket 21 Discharge pocket 22 Sealing pocket 32 Flow control valve 33 Pressure sensor 33s Detection value 34 Controller 34s Opening adjustment signal 36 Gas tank (seal gas)

Claims (2)

Attached to the compressor from which oxygen is supplied from the oxygen generation facility to the suction port via the oxygen suction pipe, a recovery pocket, a discharge pocket, in order from the high pressure side to the low pressure side in the housing part through which the impeller rotary shaft is inserted, And a labyrinth-type shaft seal device body formed with a sealing pocket,
The oxygen suction pipe is connected to the recovery pocket of the shaft seal device body through an oxygen recovery pipe,
The discharge pocket of the shaft seal device body is connected to a discharge pipe whose downstream end is open to the atmosphere,
Connect the seal gas supply piping connected to the seal gas supply source to the seal pocket of the shaft seal device body,
Incorporated into the oxygen recovery pipe into the flow rate adjustment valve,
A pressure sensor for detecting the internal pressure of the recovery pocket is provided;
A controller for reducing or increasing the amount of oxygen flowing through the oxygen recovery pipe by adjusting the opening of the flow rate adjusting valve so that the detected value of the pressure sensor exceeds a preset lower limit range of the internal pressure is provided. An oxygen compressor sealing device characterized by the above. Oxygen boosted by the compressor is attached to the latter stage compressor that is supplied to the suction port via the oxygen supply pipe, and is sequentially recovered from the high pressure side to the low pressure side in the housing portion through which the impeller rotary shaft is inserted. A labyrinth-type rear shaft sealing device body having a pocket, a discharge pocket, and a sealing pocket,
The recovery pocket of the shaft seal device main body is communicated with the recovery pocket of the main shaft seal device body,
The discharge pocket of the shaft seal device main body is communicated with the discharge pocket of the shaft seal device main body,
The sealing device for an oxygen compressor according to claim 1, wherein the sealing pocket of the shaft sealing device body is communicated with the sealing pocket of the latter shaft sealing device body.

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