Operation of gas turbine power plant with carbon dioxide separation
View Patent ↗The invention relates to a method for operating a gas turbine power plant, including a gas turbine, a HRSG following the gas turbine, an exhaust gas blower, and a carbon dioxide separation plant which separates the carbon dioxide contained in the exhaust gases and discharges it to a carbon dioxide outlet, the gas turbine, HRSG, exhaust gas blower, and carbon dioxide separation plant being connected by means of exhaust gas lines. According to the method a trip of the gas turbine power plant includes the steps of: stopping the fuel supply, switching off the exhaust gas blower, and controlling the opening angle of a VIGV at a position bigger or equal to a position required to keep a pressure in the exhaust gas lines between the HRSG and the exhaust gas blower above a minimum required pressure. The invention relates, further relates to a gas turbine power plant configured to carry out such a method.
1. A method for operating a gas turbine power plant in the event of an emergency shutdown, the gas turbine power plant including a gas turbine, a HRSG downstream of the gas turbine, an exhaust gas blower, and a carbon dioxide separation plant which separates carbon dioxide contained in exhaust gases and discharges separated carbon dioxide to a carbon dioxide outlet, the gas turbine, HRSG, exhaust gas blower, and carbon dioxide separation plant being connected by exhaust gas lines, the method comprising:
stopping a fuel supply, switching off the exhaust gas blower, and controlling an opening angle of a VIGV at a position larger than or equal to a position configured to keep a pressure in the exhaust gas lines between the HRSG and the exhaust gas blower above a minimum required pressure to prevent hazardous pressure differences between the exhaust gas side of the HRSG and ambient air.
2. The method for operating a gas turbine power plant according to claim 1 , wherein the opening angle of the VIGV is controlled as a function of the pressure in the exhaust gas lines between the HRSG and the exhaust gas blower.
3. The method for operating a gas turbine power plant according to claim 1 , wherein the opening angle of the VIGV is controlled as a function of the pressure in the exhaust gas lines between an exhaust gas re-cooler and the exhaust gas blower.
4. The method for operating a gas turbine power plant according to claim 1 , wherein the opening angle of the VIGV is kept unchanged at the position when an emergency shutdown signal was received at an emergency shutdown initiation time until a first delay time is reached.
5. The method for operating a gas turbine power plant according to claim 4 , wherein the VIGV is closed to a VIGV closed position until a VIGV closed time is reached.
6. The method for operating a gas turbine power plant according to claim 5 , wherein a power supply to the VIGV is deactivated when a third delay time is reached.
7. The method for operating a gas turbine power plant according to claim 5 , wherein a power supply to the VIGV is deactivated once the VIGV reaches the VIGV closed position.
8. The method for operating a gas turbine power plant according to claim 1 , wherein the opening angle of the VIGV is increased to an VIGV open position when an emergency shutdown signal was received at an emergency shutdown initiation time.
9. The method for operating a gas turbine power plant according to claim 1 , wherein the opening angle of the VIGV is kept at an opening angle larger than or equal to the opening angle of the VIGV at the time when an emergency shutdown signal was received until a speed of the gas turbine is reduced to a speed limit for closing the VIGV.
10. The method for operating a gas turbine power plant according to claim 1 , wherein a cooling air re-cooler is switched off when the emergency shutdown is initiated.
11. A gas turbine power plant, comprising:
a gas turbine;
a HRSG following the gas turbine;
an exhaust gas blower;
a carbon dioxide separation plant configured to separate the carbon dioxide contained in exhaust gases from the gas turbine, HRSG and exhaust gas blower and discharge separated carbon dioxide to a carbon dioxide outlet, the gas turbine, HRSG, exhaust gas blower, carbon dioxide separation plant being connected by exhaust gas lines; and
a controller configured to control the opening angle of a VIGV at a position larger than or equal to a position configured to keep a pressure in the exhaust gas lines between the HRSG and the exhaust gas blower above a minimum required pressure during a trip of the gas turbine power plant to prevent hazardous pressure differences between the exhaust gas side of the HRSG and ambient air.
12. A gas turbine power plant according to claim 11 comprising:
at least one of a HRSG exit pressure sensor and an exhaust gas blower inlet pressure sensor.
13. A gas turbine power plant according to claim 12 wherein the controller is configured to open the VIGV as a function of at least one of a pressure measured by the HRSG exit pressure sensor and a pressure measured by the exhaust gas blower inlet pressure sensor.