Pump assembly and method

Abstract

A pump assembly comprises a centrifugal pump configured to pump a multiphase fluid, a suction conduit in fluid communication with the centrifugal pump, and a discharge conduit in fluid communication with the centrifugal pump. The pump further comprises an eductor comprising one or more motive nozzles disposed within the suction conduit. Wherein the one or more motive nozzles are configured to introduce a motive fluid into the suction conduit and toward the centrifugal pump along a suction direction roughly co-directional with the suction conduit toward the centrifugal pump. A method and a pump assembly for pumping a multiphase fluid are also presented.

1 . A pump assembly for pumping a multiphase fluid, the pump assembly comprising:
 a centrifugal pump configured to pump a multiphase fluid;   a suction conduit in fluid communication with the centrifugal pump;   a discharge conduit in fluid communication with the centrifugal pump; and   an eductor comprising one or more motive nozzles disposed within the suction conduit; wherein the one or more motive nozzles are configured to introduce a motive fluid into the suction conduit and toward the centrifugal pump along a suction direction roughly co-directional with the suction conduit toward the centrifugal pump.   
     
     
         2 . The pump assembly of  claim 1 , wherein at least one of the one or more motive nozzles is disposed along an axis parallel to an axis of the suction conduit. 
     
     
         3 . The pump assembly of  claim 1 , wherein at least one of the one or more motive nozzles is coaxial with the suction conduit. 
     
     
         4 . The pump assembly of  claim 1 , wherein the eductor is in fluid communication with the discharge conduit and is configured to receive at least a portion of a discharge fluid. 
     
     
         5 . The pump assembly of  claim 4 , wherein the centrifugal pump is a multistage centrifugal pump. 
     
     
         6 . The pump assembly of  claim 4 , further comprising a recirculation apparatus disposed between the discharge conduit and the eductor, the recirculation apparatus being configured to deliver the at least a portion of the discharge fluid into the eductor. 
     
     
         7 . The pump assembly of  claim 4 , further comprising a control valve disposed between the eductor and the discharge conduit. 
     
     
         8 . The pump assembly of  claim 4 , further comprising a detector for detecting a gas volume fraction of one or more of the multiphase fluid, and a mixture fluid of the motive fluid and the multiphase fluid. 
     
     
         9 . A method for pumping a multiphase fluid, the method comprising:
 introducing a multiphase fluid into a centrifugal pump via a suction conduit;   receiving a discharge fluid from the centrifugal pump via a discharge conduit; and   introducing a motive fluid into the multiphase fluid such that from initial contact of the multiphase fluid and the motive fluid, both fluids move unidirectionally along a flow path leading to the centrifugal pump.   
     
     
         10 . The method of  claim 9 , wherein the motive fluid being introduced has a total pressure at least equal the total pressure of the multiphase fluid in the suction conduit. 
     
     
         11 . The method of  claim 9 , wherein the motive fluid has a lower gas volume fraction than that of the multiphase fluid. 
     
     
         12 . The method of  claim 9 , wherein the motive fluid is introduced into the multiphase fluid via one or more motive nozzles. 
     
     
         13 . The method of  claim 12 , wherein at least a portion of the discharge fluid is used as the motive fluid. 
     
     
         14 . The method  claim 13 , further comprising directing a portion of the discharge fluid to a recirculation apparatus in fluid communication with the one or more of the motive nozzles via a conduit. 
     
     
         15 . The method of  claim 9 , further comprising detecting a gas volume fraction of one or more of the multiphase fluid, and a mixture fluid of the motive fluid and the multiphase fluid in the suction conduit. 
     
     
         16 . The method of  claim 15 , wherein said detecting triggers a control valve to regulate the introduction of motive fluid into the multiphase fluid. 
     
     
         17 . A pump assembly for pumping a multiphase fluid, the pump assembly comprising:
 a plurality of centrifugal pumps configured to pump a multiphase fluid;   a suction conduit in fluid communication with the plurality of the centrifugal pumps;   a discharge conduit in fluid communication with the plurality of the centrifugal pumps; and   an eductor comprising one or more motive nozzles disposed within the suction conduit and configured to extend along a suction direction of the multiphase fluid so as to introduce a motive fluid into the suction conduit and toward the plurality of the centrifugal pumps.   
     
     
         18 . The pump assembly of  claim 17 , wherein at least one of the one or more motive nozzles is disposed along an axis parallel to an axis of the suction conduit. 
     
     
         19 . The pump assembly of  claim 17 , wherein at least one of the one or more motive nozzles is disposed along an axis having an acute angle with an axis of the suction conduit. 
     
     
         20 . The pump assembly of  claim 17 , wherein the eductor is in fluid communication with the discharge conduit and is configured to receive at least a portion of a discharge fluid. 
     
     
         21 . The pump assembly of  claim 17 , wherein the plurality of centrifugal pumps are configured in parallel. 
     
     
         22 . The pump assembly of  claim 17 , wherein the plurality of centrifugal pumps are configured in series.