Oil removal from a turbine of an organic rankine cycle (orc) system

Abstract

A method and system for removing oil in an organic rankine cycle (ORC) system ( 10 ) is used to prevent failures in the ORC system ( 10 ), especially during startup. The ORC system ( 10 ) includes an evaporator, a turbine ( 18 ), a condenser and a pump, and is configured to circulate a refrigerant ( 22 ) through the ORC system ( 10 ). The oil-removal system is used to remove oil from certain areas of the turbine ( 18 ), and includes an eductor line ( 32 ) and an eductor system ( 20 ). The eductor line ( 32 ) is located upstream of the turbine ( 18 ) and configured to receive a portion of the refrigerant ( 22 b ) exiting the evaporator. The eductor line ( 32 ) delivers the refrigerant ( 22 b ) to an eductor system ( 20 ) configured to remove oil from inside the turbine ( 18 ) and deliver the oil to an oil sump ( 58 ).

1 . An oil-removal system for preventing failures in an organic rankine cycle (ORC) system having an evaporator, a turbine, a condenser and a pump, and configured to circulate a refrigerant through the ORC system, the oil-removal system comprising:
 an eductor line located upstream of the turbine and configured to receive a portion of the refrigerant exiting the evaporator; and   an eductor system configured to receive the refrigerant from the eductor line and extract liquid out of the turbine.   
     
     
         2 . The oil-removal system of  claim 1  wherein the eductor system comprises:
 a first eductor configured to receive the refrigerant from the eductor line and extract liquid out of a discharge housing of the turbine. 
 
     
     
         3 . The oil-removal system of  claim 2  wherein the eductor system comprises:
 a second eductor configured to receive the refrigerant from the eductor line and extract liquid out of a high pressure volute of the turbine. 
 
     
     
         4 . The oil-removal system of  claim 1  further comprising:
 an oil sump configured to receive the liquid extracted from the eductor system. 
 
     
     
         5 . The oil-removal system of  claim 1  wherein the refrigerant exiting the evaporator is a vapor. 
     
     
         6 . The oil-removal system of  claim 1  wherein the refrigerant exiting the evaporator includes oil. 
     
     
         7 . The oil-removal system of  claim 1  wherein the liquid extracted from the turbine includes oil, refrigerant, and combinations thereof. 
     
     
         8 . The oil-removal system of  claim 1  wherein the eductor line comprises a filter configured to remove particulates from the refrigerant. 
     
     
         9 . An organic rankine cycle (ORC) system for generating power, the ORC system comprising:
 a condenser configured to condense a vaporized refrigerant;   a pump configured to increase a pressure of the condensed refrigerant;   an evaporator configured to receive the condensed refrigerant and vaporize the refrigerant;   a turbine configured to receive the vaporized refrigerant and generate power, wherein the turbine includes an impeller, a discharge housing, a high pressure volute, and an oil sump;   an inlet valve configured to control a delivery of refrigerant from the evaporator to the turbine;   a bypass valve configured to prevent the refrigerant from flowing through the turbine during a startup of the turbine, and divert the refrigerant to the condenser;   an eductor line located upstream of the inlet valve and configured to receive a portion of the refrigerant from the evaporator; and   an eductor system configured to receive the refrigerant from the eductor line and extract liquid out of the turbine.   
     
     
         10 . The ORC system of  claim 9  wherein the eductor system comprises:
 a first eductor configured to receive refrigerant from the eductor line and suck liquid out of the discharge housing of the turbine. 
 
     
     
         11 . The ORC system of  claim 10  wherein the eductor system comprises:
 a second eductor configured to receive refrigerant from the eductor line and suck liquid out of the high pressure volute of the turbine. 
 
     
     
         12 . The ORC system of  claim 9  wherein the inlet valve is in a closed position when the bypass valve is in an open position. 
     
     
         13 . The ORC system of  claim 9  wherein a weight of the refrigerant received by the eductor line is less than one percent of a total weight of refrigerant from the evaporator. 
     
     
         14 . The ORC system of  claim 9  wherein the eductor line includes a filter configured to remove particulates from the refrigerant. 
     
     
         15 . A method of operating an organic rankine cycle (ORC) system having an evaporator, a turbine, and a refrigerant configured to circulate through the evaporator and the turbine, the method comprising:
 preventing the refrigerant exiting the evaporator from passing through the turbine during a startup of the turbine;   delivering the refrigerant from the evaporator to a bypass line configured to deliver the refrigerant to the condenser during a startup of the turbine;   delivering a portion of the refrigerant from the evaporator to an eductor system; and   extracting liquid out of the turbine using the eductor system.   
     
     
         16 . The method of  claim 15  wherein delivering a portion of the refrigerant from the evaporator to the eductor system includes:
 delivering a first portion of the refrigerant to a first eductor, wherein the first eductor is configured to extract liquid from a discharge housing of the turbine; and 
 delivering a second portion of the refrigerant to a second eductor, wherein the second eductor is configured to extract liquid from a high pressure volute of the turbine. 
 
     
     
         17 . The method of  claim 15  wherein delivering a portion of the refrigerant from the evaporator to an eductor system is performed by an eductor line located upstream of the turbine. 
     
     
         18 . The method of  claim 15  wherein the portion of the refrigerant delivered to the eductor system is less than one percent of a total weight of refrigerant from the evaporator. 
     
     
         19 . The method of  claim 15  further comprising:
 delivering the liquid extracted out of the turbine to an oil sump of the turbine. 
 
     
     
         20 . The method of  claim 15  wherein the liquid extracted from the turbine includes at least one of oil, refrigerant, and combinations thereof.