Systems and methods for adjusting floor pressure levels to improve combined cycle plant startup

Patent metadata

Field	Value
Publication number	US-10041378-B2
Application number	US-201514592222-A
Country	US
Kind code	B2
Filing date	Jan 8, 2015
Priority date	Jan 8, 2015
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A method for adjusting startup floor pressure levels of HRSG steam circuits is implemented by a pressure controlling computing device including a processor and a memory. The method includes receiving a plurality of measured plant operating values associated with a HRSG steam circuit, identifying a plurality of candidate pressure levels for use in pressurizing the HRSG steam circuit, determining a calculated steam velocity level for each of the plurality of candidate pressure levels, identifying a steam velocity limit for a steam piping section of the HRSG steam circuit, selecting a lowest pressure level of the plurality of candidate pressure levels, wherein the lowest pressure level is associated with a determined calculated steam velocity level that does not exceed the identified velocity limit, and pressurizing the HRSG steam circuit to the selected lowest pressure level.

First claim

What is claimed is:

1. A pressure controlling computing device for adjusting floor pressure levels of HRSG steam circuits during a pre-warming phase, said pressure controlling computing device comprising a processor in communication with a memory, said processor is programmed to:
receive a plurality of measured plant operating values associated with a HRSG steam circuit;
identify a plurality of candidate pressure levels for use in pressurizing the HRSG steam circuit to a steam pressure that is below a floor pressure suitable for steam admission to a steam turbine;
determine a calculated steam velocity level for each of the plurality of candidate pressure levels;
identify a steam velocity limit for a steam piping section of the HRSG steam circuit;
compare each calculated steam velocity level to the identified steam velocity limit;
identify, based upon the comparison, a plurality of calculated steam velocity levels that do not exceed the steam velocity limit;
select a lowest candidate pressure level of the plurality of candidate pressure levels, wherein the lowest candidate pressure level is associated with one of the plurality of calculated steam velocity levels that does not exceed the steam velocity limit; and
pressurize the HRSG steam circuit to the selected lowest candidate pressure level to pre-warm the HRSG steam circuit prior to steam admission to the steam turbine.

2. The pressure controlling computing device of claim 1 , further configured to:
open at least one steam bypass valve associated with the HRSG steam circuit upon pressurizing the HRSG steam circuit to the selected lowest candidate pressure level.

3. The pressure controlling computing device of claim 2 , further configured to:
receive a plurality of pipe and steam temperature data associated with each section of a plurality of sections of the HRSG steam circuit;
identify an admission temperature level associated with at least one section of the plurality of sections; and
determine that a steam temperature level meets the admission temperature level associated with the at least one section, the steam temperature level associated with the plurality of pipe and steam temperature data;
initiate steam admission to the at least one section.

4. The pressure controlling computing device of claim 1 , further configured to:
identify a pressure buffer associated with the HRSG steam circuit; and
adjust the selected lowest candidate pressure level with the pressure buffer.

5. The pressure controlling computing device of claim 1 , further configured to:
monitor the measured plant operating values associated with the HRSG steam circuit to identify a variance between actual operating values and target operating values; and
dynamically adjust the selected lowest candidate pressure level based on the identified variance.

6. The pressure controlling computing device of claim 1 , further configured to:
identify a projected drum swell associated with the selected lowest candidate pressure level; and
assess projected drum swell, and adjust the selected lowest candidate pressure level upwards as necessary to satisfy a drum swell threshold.

7. The pressure controlling computing device of claim 1 , further configured to:
identify a performance impact on a mist eliminator associated with steam-water separation efficiency at the selected lowest candidate pressure level; and
assess mist eliminator performance and adjust the selected lowest candidate pressure level upwards as necessary to satisfy a mist eliminator performance threshold.

8. A method for adjusting floor pressure levels of HRSG steam circuits using the device of claim 1 , said method comprising: receiving a plurality of measured plant operating values associated with a HRSG steam circuit; identifying a plurality of candidate pressure levels for use in pressurizing the HRSG steam circuit; determining a calculated steam velocity level for each of the plurality of candidate pressure levels; identifying a steam velocity limit for a steam piping section of the HRSG steam circuit; selecting a lowest pressure level of the plurality of candidate pressure levels, wherein the lowest pressure level is associated with a determined calculated steam velocity level that does not exceed the identified velocity limit; and pressurizing the HRSG steam circuit to the selected lowest pressure level.

9. The method of claim 8 , further comprising:
opening at least one steam bypass valve associated with the HRSG steam circuit upon pressurizing the HRSG steam circuit to the selected lowest pressure level.

10. The method of claim 9 , further comprising:
receiving a plurality of pipe and steam temperature data associated with each section of the HRSG steam circuit supply to each steam turbine section;
identifying an admission temperature level associated with the steam turbine section;
determining that a steam temperature level meets the admission temperature level, the steam temperature level associated with the plurality of steam temperature data; and
initiating steam admission to the steam turbine section.

11. The method of claim 8 , further comprising:
identifying a pressure buffer associated with the HRSG steam circuit; and
adjusting the selected lowest pressure level with the pressure buffer.

12. The method of claim 8 , further comprising:
monitoring the measured plant operating values associated with the HRSG steam circuit to identify a variance between actual operating values and target operating values; and
dynamically adjusting the selected lowest pressure level based on the identified variance.

13. The method of claim 8 , further comprising:
identifying a projected drum swell associated with the selected lowest pressure level; and
validating that the drum swell does not exceed a drum swell threshold.

14. The method of claim 8 , further comprising:
identifying a performance impact on a mist eliminator associated with steam-water separation efficiency at the selected lowest pressure level; and
validating that the performance impact does not exceed a steam-water separation efficiency threshold.

15. At least one non-transitory computer-readable storage media for adjusting floor pressure levels of HRSG steam circuits during a pre-warming phase, the storage media having computer-executable instructions embodied thereon, wherein when executed by at least one processor of a pressure controlling computing device, the computer-executable instructions cause the processor to:
receive a plurality of measured plant operating values associated with a HRSG steam circuit;
identify a plurality of candidate pressure levels for use in pressurizing the HRSG steam circuit to a steam pressure that is below a floor pressure suitable for steam admission to a steam turbine;
determine a calculated steam velocity level for each of the plurality of candidate pressure levels;
identify a steam velocity limit for a steam piping section of the HRSG steam circuit;
compare each calculated steam velocity level to the identified steam velocity limit;
identify, based upon the comparison, a plurality of calculated steam velocity levels that do not exceed the steam velocity limit;
select a lowest candidate pressure level of the plurality of candidate pressure levels, wherein the lowest candidate pressure level is associated with one of the plurality of calculated steam velocity levels that does not exceed the steam velocity limit; and
pressurize the HRSG steam circuit to the selected lowest candidate pressure level to pre-warm the HRSG steam circuit prior to steam admission to the steam turbine.

Assignees

• Gen Electric

Inventors

• Tong Leslie Yung Min
• Smith Raub Warfield
• Rancruel Diego Fernando
• Karaca Erhan
• Jones Charles Michael
• Jones Bryan Michael

Classifications

• F01K23/108

  Regulating means specially adapted therefor · CPC title

• F01K13/02 Primary

  Controlling, e.g. stopping or starting · CPC title

• Y02E20/16

  Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] · CPC title