Condensate polisher circuit

• US 8,112,997 B2
• Filed: 02/06/2009
• Issued: 02/14/2012
• Est. Priority Date: 04/28/2008
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Energy Incorporated (Siemens AG)
• Inventors: Bellows, James C.
• Primary Examiner(s): NGUYEN, HOANG M
• Application Number:
  US12/366,738
• Publication Number:
  US 20090266076A1
• Time in Patent Office: 1,103 Days
• Field of Search: 60685-690
• US Class Current: 60/686
• CPC Class Codes: F01K 19/00 Regenerating or otherwise treating steam exhausted from steam engine plant F01K3/006 takes precedence plants characterised by use of means for storing steam in an alkali to increase steam pressure F01K5/00; returning condensate to boiler F22D
• CPC Class Codes: F01K 9/003 condenser cooling circuits

Abstract

A power generating system including a working fluid circuit. The power generating system includes a condenser system in the working fluid circuit and a condensate polisher circuit. The condenser system receives a working fluid that includes steam or a combination of water and steam and condenses at least a portion of the working fluid into a condensate. The condensate has a temperature above a predetermined upper operating temperature. The condensate polisher circuit is branched off from the working fluid circuit and receives and treats said condensate from the working fluid circuit and returns treated condensate to the working fluid circuit. The condensate polisher circuit includes a heat exchanger that reduces the temperature of the condensate at least to the upper operating temperature and a condensate polisher that removes contaminants from the condensate to bring the condensate to a predetermined purity.

Claims

1. A power generating system including a working fluid circuit comprising:

a condenser system in the working fluid circuit that receives a working fluid comprising steam or a combination of water and steam and condenses at least a portion of said working fluid into a condensate, said condensate having a temperature above a predetermined upper operating temperature;

a condensate polisher circuit branched off from the working fluid circuit that receives and treats said condensate from the working fluid circuit and returns treated condensate to the working fluid circuit, said condensate polisher circuit comprising;

a valve that controls a passage of said condensate into said condensate polisher circuit;

a controller that controls an opening and a closing of said valve based on measurements received from at least one sample point;

a heat exchanger that reduces said temperature of said condensate equal to or below said upper operating temperature; and

a condensate polisher that removes contaminants from said condensate to bring said condensate to a predetermined purity.

2. The power generating system as set out in claim 1, wherein a pressure within a condenser of said condenser system is equal to or greater an ambient pressure during a normal operating mode of the condenser.

3. The power generating system as set out in claim 1, further comprising a condensate receiver tank for receiving said condensate from said condenser system.

4. The power generating system as set out in claim 3, wherein said condensate polisher circuit is branched off of said condensate receiver tank, and wherein said condensate is passed into said condensate receiver tank after contaminants are removed from said condensate in said condensate polisher.

5. The power generating system as set out in claim 1, further comprising a pump that pumps said condensate through said condensate polisher circuit, said controller activates and deactivates said pump based on said measurements received from said at least one sample point.

6. The power generating system as set out in claim 1, wherein said upper operating temperature is about 60°

Celsius and wherein said contaminants comprise at least one of sodium, chloride, and carbon dioxide.

7. The power generating system as set out in claim 1, wherein said heat exchanger reduces said temperature of said condensate equal to or below a predetermined lower operating temperature, said lower operating temperature being about 50°

Celsius, and wherein said contaminants comprise at least silica.

8. The power generating system as set out in claim 1, wherein a return flow portion of said condensate that has been cooled by said heat exchanger is used to cool an inlet flow portion of said condensate in said heat exchanger.

9. A condensate polisher circuit in a power generating system that includes a working fluid circuit having a condenser system, the condenser system receiving a working fluid comprising steam or a combination of water and steam and condensing at least a portion of the working fluid into a condensate having a temperature above a predetermined upper operating temperature, the condensate polisher circuit comprising:

an upstream heat exchanger;

a downstream heat exchanger disposed downstream from said upstream heat exchanger, said upstream and downstream heat exchangers cooperating to reduce the temperature of an inlet flow portion of the condensate equal to or below the upper operating temperature; and

a condensate polisher that removes contaminants from the condensate to bring the condensate to a predetermined purity.

10. The condensate polisher circuit as set out in claim 9, wherein said inlet flow portion of the condensate in said upstream heat exchanger is cooled by a return flow portion of the condensate downstream from said downstream heat exchanger.

11. The condensate polisher circuit as set out in claim 10, wherein said return flow portion of the condensate comprises condensate that has been cooled by at least one of said upstream and downstream heat exchangers and is used to cool said inlet flow portion of the condensate in said upstream heat exchanger.

12. The condensate polisher circuit as set out in claim 9, further comprising a valve that controls a passage of the condensate into said downstream heat exchanger, a portion of the condensate permitted to flow through said valve and into said downstream heat exchanger based on a cooling capacity of said downstream heat exchanger and a temperature of said inlet flow portion of the condensate.

13. The condensate polisher circuit as set out in claim 9, further comprising a first valve that controls a passage of the condensate into said condensate polisher and a second valve that controls a passage of the condensate though a bypass of said condensate polisher, wherein a controller controls opening and closing of said first and second valves based on the temperature of the condensate.

14. The condensate polisher circuit as set out in claim 13, wherein said controller causes said first valve to close and said second valve to open when the temperature of the condensate is greater than the upper operating temperature and said controller causes said first valve to open and said second valve to close when the temperature of the condensate is equal to or less than the upper operating temperature.

18. The condensate polisher circuit as set out in claim 14, wherein the condensate passing through the bypass of said condensate polisher when said second valve is open is subsequently reintroduced into the condensate polisher circuit for further cooling by at least one of said upstream and downstream heat exchangers.

15. A method for treating condensate in a steam generating system including a working fluid circuit and a condenser system, the condenser system receiving a working fluid comprising steam or a combination of water and steam and condensing at least a portion of the working fluid into the condensate having a temperature above a predetermined upper operating temperature, the method comprising:

passing the condensate from the working fluid circuit into a condensate polisher circuit comprising;

passing the condensate through at least one heat exchanger included in the condensate polisher circuit, the at least one heat exchanger lowering a temperature of the condensate equal to or below the upper operating temperature;

passing the condensate into a condensate polisher, the condensate polisher treating the condensate comprising removing contaminants from the condensate; and

using a return flow portion of the condensate to cool an inlet flow portion of condensate, the return flow portion of the condensate exiting the condensate polisher on its way back into the working fluid circuit, and the inlet flow portion of the condensate entering the at least one heat exchanger from the working fluid circuit; and

passing the treated condensate from condensate polisher circuit back into the working fluid circuit.

16. The method according to claim 15, wherein passing the condensate from the working fluid circuit into a condensate polisher circuit comprises passing the condensate through a condensate polisher circuit only during a non-typical operating state of the steam generating system when the condensate comprises an undesirable purity, and by-passing the condensate polisher circuit during operation of the steam generating system when the condensate conforms to a predetermined purity.

17. The method according to claim 15, wherein the return flow portion of the condensate exits the condensate polisher on its way back into a condensate receiver tank included in the working fluid circuit, and the inlet flow portion of the condensate enters the at least one heat exchanger from the condensate receiver tank.

19. The method according to claim 15, wherein passing the condensate through at least one heat exchanger comprises passing the condensate through an upstream heat exchanger and a downstream heat exchanger, the upstream and downstream heat exchangers cooperating to reduce the temperature of the inlet flow portion of the condensate equal to or below the upper operating temperature.

20. The method according to claim 15, wherein passing the condensate through at least one heat exchanger comprises:

passing the condensate through the at least one heat exchanger, and, if the temperature of the condensate is not lowered by the at least one heat exchanger equal to or below the upper operating temperature, causing the condensate to bypass the condensate polisher; and

repeatedly passing the condensate through the at least one heat exchanger and causing the condensate to bypass the condensate polisher until the temperature of the condensate is lowered equal to or below the upper operating temperature, and then passing the condensate into the condensate polisher.