JP5320366B2 - Compression device - Google Patents

Description

  The present invention relates to a compressor that operates a turbine with recovered steam or the like and uses the turbine as a part of a power source of a centrifugal compressor.

  Conventionally, there is a compression device disclosed in Patent Documents 1 and 2, for example, as this type of compression device. First, the compression apparatus shown in Patent Document 1 will be described with reference to FIG. FIG. 3 is a diagram showing a configuration of a conventional compression apparatus.

  This conventional compression apparatus 41 is configured to operate an expansion turbine with steam and use the expansion turbine as a part of a power source that drives a plurality of centrifugal compressors. As shown in FIG. 3, the compression device 41 has a speed increasing device 42 formed by engaging a bull gear 43 with two pinion gears 45 and 47. The impeller 51a of the first stage centrifugal compressor (turbo compressor) is directly attached to one end of the pinion shaft 46 of the pinion gear 45 of the speed increaser 42, and the second stage is attached to the other end. The impeller 52a of the centrifugal compressor is directly attached. The impeller 53a of the third stage centrifugal compressor is directly attached to one end of the pinion shaft 48 of the pinion gear 47 of the speed increaser 42, and the turbine impeller (turbine rotor) of the expansion turbine is attached to the other end. 56a is directly attached.

  The first-stage centrifugal air compressor 60 having the impeller 51a for compressing the air flowing in through the air inflow pipe 59 is connected to the first-stage cooler 57 by the first-stage compressed air outflow pipe 60. The first stage compressed air compressed by the compressor is cooled by the first stage cooler 57. The first-stage cooler 57 to the second-stage cooler 58 communicate with a two-stage compressed air outflow pipe 62 via a two-stage compression air inflow pipe 61 and a two-stage centrifugal compressor having an impeller 52a. The two-stage compressed air compressed by the two-stage centrifugal compressor is cooled by the two-stage cooler 58. Furthermore, a three-stage turbo air compressor 63 having an impeller 53a from the two-stage cooler 58 communicates with a three-stage compression air inflow conduit 63, and is compressed by the two-stage turbo compressor and the two-stage cooling. The two-stage compressed air cooled by the vessel 58 is compressed by the three-stage turbo compressor and then flows out through the three-stage compressed air outflow pipe 64.

  In the compression device 41 disclosed in Patent Document 1, when the amount of pressure steam is sufficient, stable operation can be performed with the driving force of only the expansion turbine, and when the amount of pressure steam is insufficient. Is connected to the bull gear shaft 44 of the bull gear 43 via a coupling (coupling), and an output shaft of an electric motor (not shown) is used, and one of the expansion turbine and the electric motor is used as a complementary power source for stable operation. Like to do.

  Next, the compression apparatus shown in Patent Document 2 will be described with reference to FIG. FIG. 4 is a diagram showing the configuration of another conventional compression apparatus.

  The conventional compression device 71 is a device that supplies compressed gas to the demand side, and includes a prime mover 72, a torque transmission mechanism 73, a centrifugal compressor (turbo compressor) 77, an expansion turbine 78, a cooler 79, a receiver tank 80, A suction filter 81, a silencer 82, a suction on / off valve 83, a regenerative on / off valve 84, a discharge valve 85, a check valve 86, a pressure sensor 87, an air volume sensor 88, a control device 89, an air supply pipe 90 and a branch pipe 91. Has been. The torque transmission mechanism 73 is a mechanism for transmitting the output torque of the prime mover 72 and the output torque of an expansion turbine 78 described later to the centrifugal compressor 77, and has one bull gear 75 and two pinion gears 74 and 76. ing.

  The compression device 71 includes a single prime mover (electric motor) 72 and a single expansion turbine 78 as a power source for rotationally driving the centrifugal compressor 77. The centrifugal compressor 77 includes three centrifugal compressors 77a, 77b, and 77c. Then, the gas is sucked from the suction port of the first stage low pressure centrifugal compressor 77a, and the first stage low pressure centrifugal compressor 77a, the second stage low pressure centrifugal compressor 77b, and the high pressure centrifugal compressor 77c compress the gas in order. The compressed gas is discharged from the discharge port of the high-pressure centrifugal compressor 77c. The expansion turbine 78 sucks the pressure gas from the suction port and discharges the expanded pressure gas from the discharge port. The output shaft of the expansion turbine 78 is connected to the rotation shaft of the high-speed pinion gear 76 of the torque transmission mechanism 73. Work is performed when the pressure gas is expanded by the expansion turbine 78, and the output is extracted from the rotating shaft.

  Further, the compression device 71 includes a regenerative on-off valve 84 that is an on-off valve. One port of the regenerative on-off valve 84 communicates with the other outlet of the branch pipe 91, and the other port of the regenerative on-off valve 84 communicates with the intake port of the expansion turbine 78. Then, by controlling the opening degree of the regenerative opening / closing valve 84, the discharge air volume of the high-pressure centrifugal compressor 77c should not fall below the surging limit air volume that is the upper limit air volume causing the surging phenomenon of the high-pressure centrifugal compressor 77c. It is preferred.

  In addition, the compression device 71 includes an air discharge valve 85 that is an on-off valve that has one port connected to the suction port of the expansion turbine 78 and discharges gas from the other port. The air discharge valve 85 is provided in a pipe that branches from a pipe that communicates with the intake port of the expansion turbine 78 from the regenerative on-off valve 84 and communicates with the silencer 82. Then, when the discharge pressure of the high-pressure centrifugal compressor 77c exceeds a predetermined value, it is preferable to increase the opening degree of the discharge valve 85. For example, the air discharge valve 85 is fully closed during normal operation, and is fully opened when the discharge pressure of the high-pressure centrifugal compressor 77c exceeds a predetermined value.

  That is, in the compressor 71, when the demand for compressed gas decreases and approaches the surging region of the high-pressure centrifugal compressor 77c, the discharge gas from the high-pressure centrifugal compressor 77c flows to the inlet of the expansion turbine 78. It is configured so that it can be selected whether to blow into the atmosphere. Of course, when the discharge gas from the high-pressure centrifugal compressor 77 c is flowed to the expansion turbine 78, the recovery power in the expansion turbine 78 is increased, and the power of the prime mover 72 can be supplemented.

JP 2000-104698 A JP 2004-360462 A

  The compression devices 41 and 71 disclosed in Patent Documents 1 and 2 described above are configured to continue to operate the expansion turbine if the centrifugal compressor is operated. Here, generally, when the fluid that drives the expansion turbine falls below an allowable minimum flow rate for operating the expansion turbine without causing an unstable phenomenon, if the expansion turbine continues to operate, the expansion turbine Will not be expanded but compressed (compressor action). In this state, if the turbine inlet temperature of the expansion turbine rises and the turbine inlet temperature exceeds the allowable temperature, the runner of the expansion turbine may be damaged by centrifugal force.

  In the compression device 41 disclosed in Patent Document 1 described above, when the flow rate of the turbine driving fluid that drives the expansion turbine decreases with a decrease in the demand for compressed gas by the centrifugal compressor, it does not fall below the allowable minimum flow rate. There is no means to make it. For this reason, this conventional compressor 41 has a problem that the runner of the expansion turbine described above may be damaged.

  On the other hand, in the compression device 71 disclosed in Patent Document 2 described above, when the demand for compressed gas by the centrifugal compressor decreases and approaches the surging region of the centrifugal compressor, the discharge from the centrifugal compressor is performed. The gas is configured to flow to the inlet of the expansion turbine. Therefore, in the conventional compression device 71, the above-described problem in the compression device 41 disclosed in Patent Document 1 is solved.

  However, in the compression device 71 disclosed in Patent Document 2, when the temperature difference between the turbine inlet temperature of the expansion turbine and the discharge temperature of the centrifugal compressor is large, the discharge gas of the centrifugal compressor is sent to the suction port of the expansion turbine. Then, the turbine rotor of the expansion turbine is rapidly cooled (usually turbine inlet temperature: 200 to 400 ° C., compressor discharge temperature: 100 to 150 ° C.). For this reason, this conventional compressor 71 has a problem that a large thermal strain is generated in the turbine rotor (the turbine rotor is composed of main parts such as a runner and a shaft), resulting in a reduction in the service life.

  Accordingly, an object of the present invention is to reduce the demand for compressed gas by the centrifugal compressor in a compressor that operates the turbine with recovered steam or the like and uses the turbine as a part of the power source of the centrifugal compressor. To provide a compression apparatus capable of continuing the operation of the apparatus without causing adverse effects such as damage to the turbine or a decrease in life due to thermal distortion even when the flow rate of the turbine driving fluid for driving the turbine decreases. It is in.

  In order to solve the above problems, the present invention takes the following technical means.

  According to a first aspect of the present invention, there is provided a compression apparatus comprising: a centrifugal compressor driven by an electric motor that is a main power source and discharging compressed gas; and a turbine that drives the centrifugal compressor as an auxiliary power source. A fluid that branches from the discharge flow path of the machine and communicates with the suction flow path of the turbine and a connection point between the branch flow path in the suction flow path and flows into the turbine A flow meter for measuring the flow rate of the gas, an on-off valve provided in the branch flow channel for opening and closing the branch flow channel, and a compressed gas from the discharge flow channel provided in the branch flow channel and flowing through the branch flow channel A heater that heats the gas, a temperature sensor that detects the temperature of the compressed gas downstream of the heater, and a flow rate measurement value measured by the flow meter is greater than a predetermined flow rate setting value In the above opening When the valve is closed and the flow rate measurement value is less than or equal to the flow rate set value, the on-off valve control means for opening the on-off valve and the temperature of the compressed gas downstream of the heater based on the temperature detection result by the temperature sensor And a heater energization control unit that controls energization of the heater so as to maintain the temperature at a predetermined temperature.

  According to a second aspect of the present invention, in the compression device according to the first aspect, the predetermined temperature is a temperature range of a turbine inlet temperature when the turbine driving fluid flows into the turbine with the on-off valve closed. It is characterized by.

  According to a third aspect of the present invention, in the compressor according to the first or second aspect, the turbine is configured such that an output of the turbine is 90 to 95% of a shaft power of the centrifugal compressor in the suction passage of the turbine. A control valve for controlling the supply amount of the turbine driving fluid flowing into the engine is provided.

  The compression device according to the present invention includes a centrifugal compressor that is driven by an electric motor that is a main power source and discharges compressed gas, and a turbine that drives the centrifugal compressor as an auxiliary power source. When a flow rate of a turbine driving fluid for driving the turbine is reduced by branching from the discharge flow channel of the machine and communicating with the suction flow channel of the turbine, the compressed gas from the centrifugal compressor (Compressed process gas) is guided to the branch flow path and heated to a predetermined temperature, and the heated compressed gas is caused to flow into the turbine together with the turbine driving fluid from the suction flow path.

  Therefore, the compressor according to the present invention has an amount that does not fall below the allowable minimum flow rate even when the flow rate of the turbine drive fluid that drives the turbine decreases as the demand for compressed gas by the centrifugal compressor decreases. The fluid can be supplied without causing a decrease in the turbine inlet temperature, whereby the operation of the apparatus can be continued without causing adverse effects such as damage to the turbine and a decrease in life due to thermal distortion.

It is a figure which shows the structure of the compression apparatus by one Embodiment of this invention. It is a figure which shows the structure of the compression apparatus by another embodiment of this invention. It is a figure which shows the structure of the conventional compression apparatus. It is a figure which shows the structure of another conventional compression apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a compression apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, in the compression device 1 of the present embodiment, a pinion gear (small gear) 4 meshes with a bull gear (large gear) 3 connected to a main power source to increase the rotation speed of the main power source. A gearbox 2 is provided. That is, an output shaft 5 a of an electric motor 5, which is a main power source of a centrifugal compressor 7 to be described later, is connected to a pull gear shaft 3 a of the bull gear 3 of the speed increaser 2 through the coupling 5.

  The impeller 7a of the centrifugal compressor 7 is directly fitted to one end of the pinion shaft 4a of the pinion gear 4 of the speed increaser 2, while the centrifugal compressor as an auxiliary power source is fitted to the other end of the pinion shaft 4a. A turbine impeller (runner) 11a of an expansion turbine 11 that drives the turbine 7 is directly fitted.

  The centrifugal compressor 7 is a turbo compressor, and sucks so-called process gas (air, nitrogen gas, etc.) through the suction flow path 8 by the rotation of the impeller 7a, compresses it, and discharges the flow path. 9 to supply compressed gas (compressed process gas) to the demand side. A flow meter 10 for measuring the flow rate of the compressed gas discharged from the centrifugal compressor 7 is provided on the outlet side of the centrifugal compressor 7 in the discharge flow path 9 of the centrifugal compressor 7.

  The expansion turbine 11 is a radial turbine that is operated by inflow of pressure steam. A suction passage 12 and a discharge passage 15 are connected to the expansion turbine 11. The turbine impeller 11a of the expansion turbine 11 is rotated by pressure steam that is a turbine driving fluid supplied through the suction flow path 12. The pressure steam flowing into the expansion turbine 11 expands with the rotation of the turbine impeller 11 a and is discharged to the discharge flow path 15. The rotation of the expansion turbine 11 is transmitted to the centrifugal compressor 7 through the pinion shaft 4a. That is, the expansion turbine 11 is operated, and the expansion turbine 11 is configured to be used as a part of a power source that drives the centrifugal compressor 7.

  In this case, the supply amount of the compressed steam supplied to the expansion turbine 11 via the suction flow path 12 is increased or decreased according to the demand amount of the compressed gas by the centrifugal compressor 7. The suction passage 12 of the expansion turbine 11 is supplied with a supply amount of turbine driving fluid (compressed steam) flowing into the expansion turbine 11 so that the output of the expansion turbine 11 is 90 to 95% of the shaft power of the centrifugal compressor 7. A control valve 13 for controlling is provided. In addition, the fluid flowing into the expansion turbine 11 at the inlet side position of the expansion turbine 11 in the suction flow path 12 of the expansion turbine 11 (position downstream of the connection point with the branch flow path 16 described later in the suction flow path 12). A turbine flow meter 14 for measuring the flow rate of the turbine is provided.

  The compressor 1 branches from the downstream position of the flow meter 10 in the discharge flow path 9 of the centrifugal compressor 7, and is upstream of the turbine flow meter 14 in the suction flow path 12 of the expansion turbine 11. A branch channel 16 communicating with the position is provided.

  The branch flow path 16 is provided with an on-off valve 17, a heater 18, a temperature sensor 19, a pressure control valve 20, and a check valve 21 in order from a branch point with the discharge flow path 9 of the centrifugal compressor 7.

  The on-off valve 17 opens and closes the branch channel 16. The heater 18 heats the compressed gas (compressed process gas) from the discharge channel 9 that flows through the branch channel 16. The temperature sensor 19 is a sensor that detects the temperature of the compressed gas on the downstream side of the heater 18. The pressure control valve 20 is for adjusting the compressed gas flowing through the branch flow path 16 to a predetermined pressure range by adjusting the opening degree thereof. The check valve 21 allows only the flow of compressed gas toward the suction flow path 12 of the expansion turbine 11.

The on-off valve 17 provided in the branch channel 16 is controlled to be opened and closed by an on-off valve control device (on-off valve control means) 23. That is, by the opening and closing valve control apparatus 23, when the flow rate measurement value measured by the turbine flowmeter 14 provided in the suction passage 12 of the expansion turbine 11 is greater than a predetermined flow setpoint Q _R is-off valve 17 closed, when the flow rate measurement value is less than the flow rate set value Q _R is adapted to open the on-off valve 17.

In this case, the flow rate set value Q _R consisting of the on-off valve 17 and the threshold value for opening and closing, it shall be determined based on the allowable minimum flow for performing the operation of the expansion turbine 11 without instability symptoms It is desirable that the predetermined range is set to a value slightly higher than the allowable minimum flow rate. The allowable minimum flow rate is determined in advance based on the specifications for each expansion turbine provided in the compressor 1.

Further, the heater 18 provided in the branch flow path 16 is controlled by a heater energization control device (heater energization control means) 22. That is, when the on-off valve 17 is opened, the heater energization control unit 22, to maintain the temperature of the compressed gas at the downstream side of the heater 18 to a predetermined temperature T _R based on the temperature detection result of the temperature sensor 19 As described above, the energization of the heater 18 for heating the compressed gas is controlled.

That is, the heater 18 passes through the branch flow path 16 when the on-off valve 17 is opened and compressed gas (for example, temperature 100 to 150 ° C.) from the centrifugal compressor 7 is guided to the branch flow path 16. The compressed gas is heated so that the temperature of the compressed gas flowing into the suction passage 12 of the expansion turbine 11 is maintained at a predetermined temperature T _R (for example, 200 to 400 ° C.). The predetermined temperature T _R is, for example 200 to 400 ° C. is set in the state where the opening and closing valve 17 is closed, i.e. at a flow rate greater than the acceptable minimum flow rate of the turbine drive fluid from inlet passage 12 to the expansion turbine 11 Therefore, it corresponds to the temperature range of the turbine inlet temperature when pressure steam flows in.

  Next, the operation of the compression apparatus 1 configured as described above will be described. The centrifugal compressor 7 is driven by an electric motor 5 that is a main power source and an expansion turbine 11 that is an auxiliary power source, and the driving force of the electric motor 5 and the expansion turbine 11 depend on the demand for compressed gas. The supply amount of the pressure steam to the suction flow path 12 is adjusted.

Then, when the flow rate measurement value measured by the turbine flowmeter 14 is greater than a predetermined flow setpoint Q _R, that is, if the pressure steam exceeding the allowable minimum flow to the expansion turbine 11 is supplied on-off valve The branch channel 16 is closed by 17.

The supply amount of pressure steam with decreasing demand of compressed gas to the expansion turbine 11 is decreased, the flow rate measurement value measured by the turbine flowmeter 14 becomes equal to or less than the flow rate set value Q _R, i.e., expansion turbine When the supply amount of pressure steam to 11 approaches the allowable minimum flow rate, the on-off valve control device 23 opens the on-off valve 17 of the branch flow path 16.

When the on-off valve 17 is opened, compressed gas (for example, temperature 100 to 150 ° C.) from the centrifugal compressor 7 flows into the branch flow path 16. The compressed gas flowing into the branch channel 16 is heated by the heater 18 controlled by the heater energization control device 22 so that the temperature thereof is maintained at a predetermined temperature T _R (for example, 200 to 400 ° C.). It is guided to the suction flow path 12 of the expansion turbine 11 through the path 16. As a result, the pressure steam and the heated compressed gas from the branch flow path 16 are supplied to the expansion turbine 11, and the driving fluid exceeding the allowable minimum flow rate of the expansion turbine 11 flows into the expansion turbine 11. It is operated without instability.

When the demand of the compressed gas is increased recovery, this quantity of the supplied pressure steam into the expansion turbine 11 is increased with the flow rate measurement value measured by the turbine flowmeter 14 and flow setpoint Q _R If it exceeds, the branch flow path 16 will be closed.

  As described above, the compression device 1 according to the present embodiment includes the centrifugal compressor 7 that is driven by the electric motor 5 that is the main power source and discharges the compressed gas, and the expansion turbine 11 that drives the centrifugal compressor 7 as the auxiliary power source. Is provided with a branch flow path 16 that branches from the discharge flow path 9 of the centrifugal compressor 7 and communicates with the suction flow path 12 of the expansion turbine 11, and the flow rate of the pressure steam that drives the expansion turbine 11 is When the pressure decreases, the compressed gas (compressed process gas) from the centrifugal compressor 7 is guided to the branch flow path 16 and heated to a predetermined temperature, and the heated compressed gas is caused to flow into the expansion turbine 11 together with the pressure steam. It is configured.

  Therefore, the compressor 1 according to the present embodiment causes the expansion turbine 11 to fall below the allowable minimum flow rate even when the flow rate of the pressure steam that drives the expansion turbine 11 decreases as the demand for compressed gas by the centrifugal compressor 7 decreases. A small amount of fluid can be supplied without reducing the turbine inlet temperature. Therefore, the operation of the apparatus can be continued without causing adverse effects such as damage to the expansion turbine 11 and a decrease in life due to thermal distortion.

  FIG. 2 is a diagram illustrating a configuration of a compression device according to another embodiment of the present invention. The compressing device 1a has the same configuration as the compressing device 1 described above except that a steam temperature sensor 24 is added, and the same reference numerals are given to portions common to both. That is, the compression device 1a of the present embodiment has the temperature of the pressure steam flowing into the expansion turbine 11 in the suction flow path 12 of the expansion turbine 11 (position upstream of the connection point with the branch flow path in the suction flow path 12). Is provided with a steam temperature sensor 24.

  In this compression device 1 a, the compressed gas flowing through the branch flow path 16 is heated by the heater energization control device 22 so that the difference between the temperature detected by the steam temperature sensor 24 and the temperature by the temperature sensor 19 is eliminated. The energization of the heater 18 is controlled. Normally, the pressure steam is sufficiently hot, so that even with this configuration, an amount of fluid that does not fall below the allowable minimum flow rate can be supplied to the expansion turbine 11 without causing a decrease in the turbine inlet temperature.

DESCRIPTION OF SYMBOLS 1, 1a ... Compression apparatus 2 ... Speed up gear 3 ... Bull gear 4 ... Pinion gear 5 ... Electric motor 6 ... Coupling 7 ... Centrifugal compressor 7a ... Impeller 8 ... Suction flow path 9 ... Discharge flow path 10 ... Flow meter 11 ... Expansion Turbine 11a ... Turbine impeller 12 ... Suction passage 13 ... Control valve 14 ... Turbine flow meter 15 ... Discharge passage 16 ... Branch passage 17 ... Open / close valve 18 ... Heater 19 ... Temperature sensor 20 ... Pressure control valve 21 ... Check Valve 22 ... Heater energization control device 23 ... Open / close valve control device 24 ... Steam temperature sensor

Claims (3)

In a compressor comprising a centrifugal compressor driven by an electric motor as a main power source and discharging compressed gas, and a turbine for driving the centrifugal compressor as an auxiliary power source,
A branch flow path branched from the discharge flow path of the centrifugal compressor and connected to the suction flow path of the turbine, and provided downstream of a connection point between the branch flow path in the suction flow path, A flow meter for measuring the flow rate of the inflowing fluid; an open / close valve provided in the branch flow path for opening and closing the branch flow path; and a discharge flow path provided in the branch flow path and flowing through the branch flow path. A heater that heats the compressed gas, a temperature sensor that is provided in the branch flow path and detects the temperature of the compressed gas downstream of the heater, and a flow rate measurement value measured by the flow meter is a predetermined flow rate setting value. When larger, the on-off valve is closed, and when the flow rate measurement value is less than or equal to the flow rate set value, the on-off valve control means for opening the on-off valve, and the downstream of the heater based on the temperature detection result by the temperature sensor. Pressure on the side Compressor for the heater energization control means for controlling the energization of the heater to maintain the temperature of the gas to a predetermined temperature, comprising the.   The compressor according to claim 1, wherein the predetermined temperature is a temperature range of a turbine inlet temperature when a turbine driving fluid flows into the turbine in a state where the on-off valve is closed.   The suction flow path of the turbine is provided with a control valve for controlling the supply amount of the turbine driving fluid flowing into the turbine so that the output of the turbine is 90 to 95% of the shaft power of the centrifugal compressor. The compression apparatus according to claim 1 or 2, wherein the compression apparatus is provided.

Images