Apparatus and method for surge prevention for centrifugal compressor

Abstract

Disclosed is an apparatus and method for surge prevention for a centrifugal compressor. An apparatus for surge prevention for a buffering vessel based centrifugal compressor according to the present invention includes a recycle pipe which connects a suction portion to a discharge portion of the centrifugal compressor, a cooler which cools compressed gas received according to an opening of a recycle valve disposed at the recycle pipe, a buffering vessel which stores the gas cooled by the cooler, and a compressor control unit which determines a surge occurrence condition to control opening and closing of the recycle valve and a buffer valve which is disposed at a rear stage of the buffering vessel.

What is claimed is: 
     
         1 . An apparatus for surge prevention for a buffering vessel based centrifugal compressor comprising:
 a recycle pipe which connects a suction portion to a discharge portion of the centrifugal compressor;   a cooler which cools compressed gas received according to an opening of a recycle valve disposed at the recycle pipe;   a buffering vessel which stores the gas cooled by the cooler; and   a compressor control unit which determines a surge occurrence condition to control opening and closing of the recycle valve and a buffer valve which is disposed at a rear stage of the buffering vessel.   
     
     
         2 . The apparatus of  claim 1 , wherein the compressor control unit receives a sensed value from a flow sensor and a first pressure sensor which are disposed at the suction portion and a second pressure sensor disposed at the discharge portion to determine the surge occurrence condition. 
     
     
         3 . The apparatus of  claim 1 , wherein the compressor control unit receives a sensed value from a level sensor disposed at the buffering vessel to control the opening and closing of the recycle valve. 
     
     
         4 . The apparatus of  claim 1 , wherein the compressor control unit opens the buffer valve to enable the gas stored in the buffering vessel to be introduced into the suction portion when an occurrence of a surge is expected. 
     
     
         5 . The apparatus of  claim 4 , wherein the compressor control unit opens the recycle valve when a surge is expected to occur due to pressure of the discharge portion in spite of a gas flow rate of the suction portion being increased by opening the buffer valve. 
     
     
         6 . A method for surge prevention for a buffering vessel based centrifugal compressor comprising:
 checking a level value of a buffering vessel which receives and stores compressed gas through a recycle pipe;   controlling opening and closing of a recycle valve according to the level value;   determining a surge occurrence condition; and   introducing the gas stored in the buffering vessel into a suction portion of the centrifugal compressor by opening a buffer valve when the surge occurrence condition is determined to be satisfied.   
     
     
         7 . The method of  claim 6 , further comprising closing the recycle valve and the buffer valve which is disposed at a rear stage of the buffering vessel before the checking. 
     
     
         8 . The method of  claim 6 , wherein the controlling opens the recycle valve to store the gas in the buffering vessel when the level value is less than a preset value and close the recycle valve when the level value is equal to or higher than the preset value. 
     
     
         9 . The method of  claim 8 , wherein the controlling enables the gas to be cooled by a cooler before being stored in the buffering vessel. 
     
     
         10 . The method of  claim 6 , wherein the determining determines a possibility of an occurrence of a surge on the basis of a gas flow rate and pressure of the suction portion of the centrifugal compressor and pressure of a discharge portion of the centrifugal compressor. 
     
     
         11 . The method of  claim 6 , further comprising, after the introducing, monitoring a possibility of an occurrence of a surge due to high pressure of a discharge portion in spite of opening the buffer valve. 
     
     
         12 . The method of  claim 11 , further comprising introducing the compressed gas in the discharge portion of the centrifugal compressor into the buffering vessel by opening the recycle valve when the possibility of an occurrence of a surge is monitored in the monitoring.