Corrected rpm calculation method for compressor, control method for compressor, and devices for implementing these methods

Patent metadata

Field	Value
Publication number	US-2016123341-A1
Application number	US-201414889296-A
Country	US
Kind code	A1
Filing date	Jun 26, 2014
Priority date	Jun 27, 2013
Publication date	May 5, 2016
Grant date	—

Abstract

An RPM of a compressor is sensed by an RPM meter, and a sound velocity of an inlet gas sucked into the compressor is sensed by a sound velocity meter. A corrected RPM computation unit finds a corrected RPM of the compressor using a reference state quantity determined by a reference specific heat ratio, a reference gas constant, and a reference temperature of the inlet gas; the RPM sensed by the RPM meter, and the sound velocity sensed by the sound velocity meter.

First claim

1 . A corrected RPM calculation device, comprising:
an acceptance unit that receives an RPM of a compressor sensed by an RPM meter and a sound velocity of an inlet gas sucked into the compressor sensed by a sound velocity meter; and a corrected RPM computation unit that finds a corrected RPM of the compressor using a reference state quantity determined by a reference specific heat ratio, a reference gas constant, and a reference temperature of the inlet gas in a reference state; the sound velocity received by the acceptance unit; and the RPM received by the acceptance unit.

2 . The corrected RPM calculation device according to claim 1 , further comprising:
the RPM meter; and the sound velocity meter.

3 . The corrected RPM calculation device according to claim 2 , wherein
the sound velocity meter includes a sonic transmitter and a sonic receiver disposed opposite each other on a pipe through which the inlet gas flows, in a direction perpendicular to an axis of the pipe.

4 . The corrected RPM calculation device according to claim 1 , further comprising
an output unit that outputs the corrected RPM found by the corrected RPM computation unit.

5 . A compressor control device, comprising:
the corrected RPM calculation device according to claim 1 ; and a surge control unit that controls a final control element to prevent surging of the compressor, the acceptance unit receiving at least an outlet pressure of the compressor sensed by a pressure gauge, and the surge control unit determining a limiting pressure ratio or a pre-limiting pressure ratio that is smaller than the limiting pressure ratio by a predetermined amount, with respect to the corrected RPM found by the corrected RPM calculation device, using a predetermined relationship between the corrected RPM and the limiting pressure ratio or the pre-limiting pressure ratio of the compressor, comparing the limiting pressure ratio or the pre-limiting pressure ratio with the actual pressure ratio of the compressor determined from the outlet pressure received by the acceptance unit, and controlling the final control element in accordance with the comparison result.

6 . The compressor control device according to claim 5 , wherein
the final control element includes an inlet flow rate regulator that regulates the flow rate of the inlet gas, and the surge control unit outputs to the inlet flow rate regulator an instruction to increase the flow rate of the inlet gas in accordance with the comparison result.

7 . The compressor control device according to claim 5 , wherein
the final control element includes a recirculation flow rate regulator that regulates the flow rate of gas returned to the inlet side of the compressor from among the gas output from the compressor, and the surge control unit outputs an instruction to the recirculation flow rate regulator to increase the flow rate of the gas returned to the inlet side in accordance with the comparison result.

8 . The compressor control device according to claim 5 , wherein
the final control element includes an extraction flow rate regulator that regulates the flow rate of the gas extracted from the compressor, and the surge control unit outputs an instruction to the extraction flow rate regulator to increase the flow rate of the gas extracted in accordance with the comparison result.

9 . The compressor control device according to claim 5 , wherein
the final control element includes a trip final control element that stops the compressor, and the surge control unit outputs an instruction to the trip final control element to execute an operation to stop the compressor in accordance with the comparison result.

10 . The compressor control device according to claim 5 , wherein
the surge control unit determines a pre-limiting pressure ratio with respect to the corrected RPM found by the corrected RPM calculation device, and outputs an instruction to the final control element when the actual pressure ratio becomes equal to or greater than the pre-limiting pressure ratio.

11 . The compressor control device according to claim 5 , further comprising:
an efficiency calculation unit that calculates an efficiency of the compressor in accordance with the corrected RPM found by the corrected RPM computation unit and the actual pressure ratio of the compressor determined from the outlet pressure received by the acceptance unit, using a predetermined relationship among the corrected RPM, the pressure ratio, and the efficiency of the compressor; and an output unit that outputs the efficiency calculated by the efficiency calculation unit.

12 . Compression equipment, comprising:
the compressor control device according to claim 5 ; the compressor; and the final control element.

13 . The compression equipment according to claim 12 , wherein
the compressor compresses fuel gas, which is burned by a combustor, as the gas.

14 . A corrected RPM calculation method, comprising:
a RPM sensing step of sensing an RPM of a compressor; a sound velocity sensing step of sensing a sound velocity of an inlet gas that is a gas sucked into the compressor; and a corrected RPM computation step of finding a corrected RPM of the compressor, using a reference state quantity determined by a reference specific heat ratio, a reference gas constant, and a reference temperature of the inlet gas in a reference state; the sound velocity sensed in the sound velocity sensing step; and the RPM sensed in the RPM sensing step.

15 . A compressor control method, executing:
the corrected RPM calculation method according to claim 14 ; an outlet pressure sensing step of sensing an outlet pressure of the compressor; and a surge control step of controlling an operation of a final control element to prevent surging of the compressor, wherein in the surge control step, a limiting pressure ratio or a pre-limiting pressure ratio that is smaller than the limiting pressure ratio by a predetermined amount is determined, with respect to the corrected RPM found by executing the corrected RPM calculation method, using a relationship between the corrected RPM and the limiting pressure ratio or the pre-limiting pressure ratio of the compressor, the limiting pressure ratio or the pre-limiting pressure ratio is compared with an actual pressure ratio of the compressor determined from the outlet pressure sensed in the outlet pressure sensing step, and the final control element is controlled in accordance with the comparison result.

16 . The compressor control method according to claim 15 , wherein
in the surge control step, the pre-limiting pressure ratio with respect to the corrected RPM found by executing the corrected RPM calculation method is determined, and if the actual pressure ratio becomes equal to or greater than the pre-limiting pressure ratio, an instruction is output to the final control element.

17 . A compressor degradation determination method, executing:
the corrected RPM calculation method according to claim 14 ; an outlet pressure sensing step of sensing an outlet pressure of the compressor; a pressure ratio computation step of finding an actual pressure ratio of the compressor determined from the outlet pressure sensed in the outlet pressure sensing step; a first efficiency calculation step of calculating an actual efficiency of the compressor; a second efficiency calculation step of calculating an efficiency of the compressor in accordance with the corrected RPM found by executing the corrected RPM calculation method and the pressure ratio found in the pressure ratio compu

Assignees

• Mitsubishi Hitachi Power Sys

Inventors

• Higashi Ryo

Classifications

• F04D29/321

  for axial flow compressors · CPC title

• G01P5/24

  by measuring the direct influence of the streaming fluid on the properties of a detecting acoustical wave · CPC title

• F04D27/001

  Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring · CPC title

• F04D27/0246 Primary

  by varying geometry within the pumps, e.g. by adjusting vanes · CPC title

• G01P21/00

  Testing or calibrating of apparatus or devices covered by the preceding groups · CPC title