Pumping system with barrier fluid delivery circuit for dry gas seals

Abstract

A pumping system for carbon dioxide applications comprises a plurality of centrifugal pumps each provided with one or more dry gas seals, and one or more barrier fluid delivery circuits for fluidly connecting the pump discharge of a pump in a running condition to at least one dry gas seal of another pump in standby condition. The pumps of the pumping system may be switched between a running condition and a standby condition through a control unit.

What we claim is: 
     
         1 . A pumping system, comprising at least a first pump and a second pump, each of said pumps being provided with one or more dry gas seals and being switchable between a standby condition and a running condition, each of said pumps comprising at least a pump intake and a pump discharge, the pumping system further comprising at least a shared process fluid delivery circuit fluidly connecting the pump discharge each of said pumps to the dry gas seal of each of said pumps. 
     
     
         2 . A pumping system according to  claim 1 , wherein said shared process fluid delivery circuit comprises a first barrier fluid delivery circuit fluidly connecting the pump discharge of said first pump to a shared line and a second barrier fluid delivery circuit fluidly connecting the pump discharge of the second pump to said shared line, said shared line being in turn fluidly connected to the dry gas seals of said pumps. 
     
     
         3 . A pumping system according to  claim 1 , wherein said shared line is provided with at least a reduction valve apt to reduce the pressure of the barrier fluid coming from the pump discharges, at least a filter, at least an heater and at least a shared header. 
     
     
         4 . A pumping system according to  claim 1 , wherein downstream to said shared header said shared branch of said shared process fluid delivery circuit splits into a first return branch line fluidly connecting said shared header to said one or more dry gas seals of the first pump, and into a second return branch line fluidly connecting said shared header to the dry gas seals of the second pump. 
     
     
         5 . A pumping system according to  claim 1 , wherein a first check valve is provided on said first barrier fluid delivery duct, and a second check valve is provided on said second barrier fluid delivery duct. 
     
     
         6 . A pumping system according to  claim 1 , wherein said pumps are centrifugal pumps. 
     
     
         7 . A pumping system according to  claim 1 , wherein said fluid discharged from the pump discharge of said first and second pump is carbon dioxide. 
     
     
         8 . Pumping system according to  claim 1 , further comprising a control unit configured to switch the operative conditions of said pumps and to control the operative conditions of said shared process fluid delivery circuit. 
     
     
         9 . A method comprising the following steps:
 receiving a barrier fluid from a discharge port of a first pump into a shared process fluid recovery circuit coupled with the discharge port;   reducing pressure of the barrier fluid; and   directing the reduced pressure barrier fluid to a dry seal of a second pump coupled with the shared process fluid recovery circuit.   
     
     
         10 . The method according to  claim 9 , wherein it further comprises the steps of:
 filtering and warming the barrier fluid in said shared process fluid recovery circuit after reducing its pressure and before directing the reduced pressure barrier fluid to the dry seal of the second pump.   
     
     
         11 . The method of  claim 9 , wherein when the first pump is in a running condition and the second pump is in a standby condition, and the barrier fluid coming from the running condition is provided to the dry seal of the standby pump. 
     
     
         12 . The method of  claim 9 , further comprising the step consisting of switching the functioning conditions of the two pumps so that the first pump reaches a standby condition and the second pump reaches a running condition, the barrier fluid coming from the running condition pump is provided to the dry seal of the standby pump. 
     
     
         13 . A pumping system according to  claim 2 , wherein said shared line is provided with at least a reduction valve apt to reduce the pressure of the barrier fluid coming from the pump discharges, at least a filter, at least an heater and at least a shared header. 
     
     
         14 . A pumping system according to  claim 2 , wherein downstream to said shared header said shared branch of said shared process fluid delivery circuit splits into a first return branch line fluidly connecting said shared header to said one or more dry gas seals of the first pump, and into a second return branch line fluidly connecting said shared header to the dry gas seals of the second pump. 
     
     
         15 . A pumping system according to  claim 2 , wherein a first check valve is provided on said first barrier fluid delivery duct, and a second check valve is provided on said second barrier fluid delivery duct. 
     
     
         16 . A pumping system according to  claim 2 , wherein said pumps are centrifugal pumps. 
     
     
         17 . A pumping system according to  claim 2 , wherein said fluid discharged from the pump discharge of said first and second pump is carbon dioxide. 
     
     
         18 . Pumping system according to  claim 2 , further comprising a control unit configured to switch the operative conditions of said pumps and to control the operative conditions of said shared process fluid delivery circuit. 
     
     
         19 . The method of  claim 10 , wherein when the first pump is in a running condition and the second pump is in a standby condition, and the barrier fluid coming from the running condition is provided to the dry seal of the standby pump. 
     
     
         20 . The method of  claim 10 , further comprising the step consisting of switching the functioning conditions of the two pumps so that the first pump reaches a standby condition and the second pump reaches a running condition, the barrier fluid coming from the running condition pump is provided to the dry seal of the standby pump