Turbine system including valve for leak off line for controlling seal steam flow
View Patent ↗A turbine system includes a valve coupled to a leak off line from a leak packing of a first turbine, the valve controlling a first steam flow used to maintain a constant self-sustaining sealing pressure to a second turbine across numerous loading conditions. A related method is also provided.
1. A steam turbine system comprising:
a high pressure (HP) turbine operatively coupled to an intermediate pressure (IP) turbine and a low pressure (LP) turbine;
a steam seal header for maintaining a constant self-sustaining sealing pressure to the LP turbine using a first steam flow in a seal steam line from a seal packing of the HP turbine;
a leak off line coupling a leak packing of the HP turbine to the IP turbine;
a connector line directly coupling the leak off line to the seal steam line upstream of the IP turbine;
a valve coupled to the connector line for controlling the first steam flow to the steam seal header; and
a controller for controlling operation of the valve,
wherein the valve delivers more steam flow to the seal steam line during a lower load condition of the IP turbine than during a higher load condition of the IP turbine such that the steam seal header uses greater than or approximately 90% of the first steam flow to maintain a sealing pressure to the LP turbine, and the steam seal header leaves approximately 10% or less of the first steam flow unused during all load conditions of the turbine system.
2. The steam turbine system of claim 1 , wherein the valve includes a diverter valve for controlling the first steam flow by diverting a portion of a second steam flow from the leak off line directly to the first steam flow in the seal steam line.
3. The steam turbine system of claim 1 , wherein the steam seal header sends the unused portion of the first steam flow to a condenser.
4. The steam turbine system of claim 1 , wherein the leak off line further includes a blocking valve.
5. A method of operating a turbine system, the method comprising:
providing:
a high pressure (HP) turbine operatively coupled to an intermediate pressure (IP) turbine and a low pressure (LP) turbine;
a leak off line coupling a leak packing of the HP turbine to the IP turbine;
a seal steam line coupling a seal packing of the HP turbine to a seal packing of the LP turbine by way of a steam seal header;
a connector line directly coupling the leak off line to the seal steam line upstream of the IP turbine; and
a valve coupled to the connector line; and
maintaining a constant self-sustaining sealing pressure to the LP turbine by:
controlling the valve coupled to the connector line to deliver more steam to a first steam flow within the seal steam line during a lower load condition of the IP turbine than during a higher load condition of the IP turbine, such that the steam seal header uses greater than approximately 90% of the first steam flow and the steam seal header leaves approximately 10% or less of the first steam flow unused during all load conditions of the turbine system.
6. The method of claim 5 , wherein the controlling includes diverting a portion of a second steam flow from the leak off line to the first steam flow in the steam seal line using the valve in the connector line.
7. The method of claim 5 , wherein the steam seal header sends the unused portion of the first steam flow to a condenser.
8. A steam turbine system comprising:
a high pressure (HP) turbine operatively coupled to an intermediate pressure (IP) turbine and a low pressure (LP) turbine;
a steam seal header coupled to a seal packing of the LP turbine for maintaining a constant self-sustaining sealing pressure to the LP turbine;
a first steam flow within a seal steam line coupling a seal packing of the HP turbine to the steam seal header;
a leak off line coupling a leak packing of the HP turbine to the IP turbine;
a connector line directly coupling the leak off line to the steam seal line upstream of the IP turbine and the steam seal header;
a valve coupled to the connector line for controlling the first steam flow to the steam seal header;
a blocking valve positioned in the leak off line upstream of the valve coupled to the connector line; and
a controller for controlling operation of the valve,
wherein the valve delivers more steam flow to the seal steam line during a lower load condition of the IP turbine than during a higher load condition of the IP turbine such that the steam seal header uses greater than approximately 90% of the first steam flow to maintain a sealing pressure to the LP turbine and the steam seal header sends approximately 10% or less of the first steam flow to a condenser during all load conditions of the turbine system.
9. The turbine system of claim 8 , wherein the valve includes a diverter valve for controlling the first steam flow by diverting a portion of a second steam flow within the leak off line to the first steam flow within the seal steam line.