Methods of varying low emission turbine gas recycle circuits and systems and apparatus related thereto

Patent metadata

Field	Value
Publication number	US-9670841-B2
Application number	US-201214002620-A
Country	US
Kind code	B2
Filing date	Mar 5, 2012
Priority date	Mar 22, 2011
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

Systems and methods are provided for varying the exhaust gas recycle circuit of low emission gas turbines. In one or more embodiments, the systems and methods incorporate alternatives to the use of a direct contact cooler. In the same or other embodiments, the systems and methods incorporate alternatives intended to reduce or eliminate the erosion or corrosion of compressor blades due to the presence of acidic water droplets in the recycled gas stream.

First claim

What is claimed is:

1. An integrated system comprising:
a gas turbine system comprising a combustion chamber configured to combust one or more oxidants and one or more fuels in the presence of a compressed recycle stream, wherein the combustion chamber directs a first discharge stream to an expander to generate a gaseous exhaust stream and at least partially drive a main compressor, wherein the one or more oxidants and the one or more fuels are separately provided to the combustion chamber so as to be in a stoichiometric ratio of between 0.9:1 and 1.1:1 in the combustion chamber; and
an exhaust gas recirculation system, wherein the main compressor compresses the gaseous exhaust stream and thereby generates the compressed recycle stream;
wherein the exhaust gas recirculation system comprises (i) at least one cooling unit configured to receive and cool the gaseous exhaust stream, (ii) at least one blower configured to receive and increase the pressure of the gaseous exhaust stream before directing a cooled recycle gas to the main compressor, (iii) a second cooling unit configured to receive the gaseous exhaust stream from the at least one blower and to adjust a temperature and lower a dew point of the gaseous exhaust stream to the main compressor thereby generating the cooled recycle gas, and (iv) a feed/effluent cross exchanger in series with the second cooling unit configured to adjust the temperature of the cooled recycle gas to achieve a dew point margin of
at least about 20° F.

2. The system of claim 1 , wherein the at least one cooling unit is a heat recovery steam generator (HSRG) configured to receive and cool the gaseous exhaust stream before introduction to the at least one blower.

3. The system of claim 2 , wherein the second cooling unit comprises a direct contact cooler (DCC) section.

4. The system of claim 2 , wherein the second cooling unit comprises a HRSG.

5. The system of claim 2 , wherein the HRSG further comprises cooling water coils and wherein the exhaust gas recirculation system further comprises a separator configured to receive the gaseous exhaust stream from the cooling water coils of the HRSG and remove water droplets from the gaseous exhaust stream before introduction to the blower.

6. The system of claim 5 wherein the separator comprises a vane pack.

7. The system of claim 3 , wherein the HRSG further comprises cooling water coils and wherein the exhaust gas recirculation system further comprises a separator configured to receive the gaseous exhaust stream from the cooling water coils of the HRSG and remove water droplets from the gaseous exhaust stream before introduction to the blower.

8. The system of claim 7 wherein the separator comprises a vane pack.

9. The system of claim 2 , wherein
the second cooling unit comprises a second HRSG and each of the first and second cooling units further comprise cooling water coils; and
the exhaust gas recirculation system further comprises a first separator configured to receive the gaseous exhaust stream from the cooling water coils of the first cooling unit and remove water droplets from the gaseous exhaust stream before introduction to the blower and a second separator configured to receive the cooled recycle gas from the cooling water coils of the second cooling unit and remove water droplets from the cooled recycle gas before introduction to the main compressor.

10. The system of claim 9 wherein the first separator, the second separator, or both of the first and second separators comprise a vane pack.

11. The system of claim 3 , wherein the exhaust gas recirculation system employs psychrometric cooling of the gaseous exhaust stream.

12. The system of claim 11 , wherein
water is added to the gaseous exhaust stream to saturate or nearly saturate the gaseous exhaust stream before introduction to the blower;
the exhaust gas recirculation system further comprises a separator configured to receive the saturated or nearly saturated gaseous exhaust stream and remove water droplets from the saturated or nearly saturated gaseous exhaust stream before introduction to the blower; and
the second cooling unit is further configured to remove water from the gaseous exhaust stream and recycle at least part of the water removed.

13. The system of claim 12 , wherein a first portion of the water removed in the second cooling unit is recycled and added to the gaseous exhaust stream upstream of the separator and a second portion of the water removed in the second cooling unit is recycled to the second cooling unit.

14. The system of claim 1 , wherein the second cooling unit is configured to cause the cooled recycle gas to have a dew point margin of at least about 30° F.

15. The system of claim 3 , wherein
the second cooling unit further comprises a glycol absorption section configured to receive the cooled recycle gas from the DCC section and at least partially dehydrate the cooled recycle gas before introduction to the main compressor; and
the exhaust gas recirculation system further comprises a glycol regeneration system configured to receive rich glycol from the glycol absorption section of the second cooling unit, thermally regenerate the rich glycol in a glycol regeneration column to form regenerated lean glycol, and return the regenerated lean glycol to the glycol absorption section.

16. The system of claim 15 , wherein the glycol regeneration system is operated under vacuum conditions.

17. The system of claim 15 , wherein the second cooling unit comprises the glycol regeneration column and the glycol regeneration column is configured to receive the gaseous exhaust stream from the blower before introduction to the DCC section.

18. The system of claim 17 , wherein the second cooling unit further comprises a desuperheating section positioned between the glycol regeneration column and the DCC section.

19. The system of claim 1 , wherein the combustion chamber is configured to combust one or more oxidants and one or more fuels in the presence of the compressed recycle stream and a high pressure steam coolant stream.

20. The system of claim 1 , wherein the compressed recycle stream includes a steam coolant, which supplements the gaseous exhaust stream.

21. A method of generating power, comprising:
separately providing at least one oxidant and at least one fuel to a combustion chamber so that the at least one oxidant and the at least one fuel have a stoichiometric ratio of between 0.9:1 and 1.1:1 in the combustion chamber;
combusting the at least one oxidant and the at least one fuel in the presence of a compressed recycle exhaust gas, thereby generating a discharge stream;
expanding the discharge stream in an expander to at least partially drive a main compressor and generate a gaseous exhaust stream; and
directing the gaseous exhaust stream to an exhaust gas recirculation system, wherein the main compressor compresses the gaseous exhaust stream and thereby generates the compressed recycle stream;
wherein the exhaust gas recirculation system comprises (i) at least one cooling unit configured to receive and cool the gaseous exhaust stream, (ii) at least one blower configured to receive and increase the pressure of the gaseous exhaust stream before directing a cooled recycle gas to the main compressor, (iii) a second cooling unit configured to receive the gaseous exhaust stream from the at least one blower and to adjust a temperature and lower a dew point of the gaseous exhaust stream to the main compressor, wherein the second cooling uni

Assignees

• Mittricker Franklin F
• Huntington Richard A
• Starcher Loren K
• Sites Omar Angus
• Exxonmobil Upstream Res Co

Inventors

• Mittricker Franklin F
• Huntington Richard A
• Starcher Loren K
• Sites Omar Angus

Classifications

• Y02E20/16

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

• F02C7/141

  of working fluid · CPC title

• F05D2260/95

  Preventing corrosion · CPC title

• F02C3/34 Primary

  with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle · CPC title

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title