Gas turbine sequence purging process
A purge process of a gas turbine supply pipe network provided with fuel (diesel or natural gas) at least partly containing synthesis gas comprises of injection of inert gas in intervalve portions or collectors of the pipe network likely to contain fuel when the fuel supply is stopped. The injection of gas is implemented in the said portions of the network according to a sequence of respective injection.
1. A purge process of a supply pipe network in a gas turbine comprising:
supplying a fuel to a supply pipe network in a gas turbine, the fuel at least partly contains synthetic gas,
stopping supplying the fuel to the supply pipe network;
while the supply of fuel is stopped, injecting inert gas in a sequential order in each of separate portions of the supply pipe network that contains fuel or hot air,
wherein the sequential order of injection of the inert gas includes injecting the inert gas in a first of the separate portions while a second of the separate portions is not injected with the inert gas, and subsequently injecting the inert gas in the second of the separate portions, the sequential order is determined by a Modified Wobbe Index of the fuel, and
after the sequential order of injection of the inert gas, resuming the supply of the fuel to the supply pipe network.
2. The purge process according to claim 1 , wherein the inert gas is supplied to the separate portions of the supply pipe network according to a supply order determined according to a configuration of the supply pipe network in a manner as to maintain a positive supply flow towards a direction of a turbine combustion chamber in the gas turbine.
3. The purge process according to claim 2 , further comprising stopping the purge process according to a sequence depending on the supply order.
4. The purge process according to claim 1 further comprising fuel supply pipes in the supply pipe network, wherein the inert gas is injected in portions of the fuel supply pipes located between fuel supply control valves.
5. The purge process according to claim 1 , further comprising hot air supply pipes in the supply pipe network, wherein the inert gas is injected in portions of the hot air supply pipes located between hot air supply control valves.
6. The purge process according to claim 1 , further comprising collectors that supply the injectors with fuel, wherein the inert gas is injected in one or each collector for supply of the injector with fuel.
7. The purge process according to claim 1 , further comprising collectors that supply the injectors with fuel, wherein the inert gas is injected in one or each collector for supply of the turbine with combustive fuel.
8. The purge process according to claim 1 , wherein the inert gas is injected at a pressure greater than a combustible gas pressure.
9. The purge process according to claim 1 , wherein the inert gas is injected at a pressure greater than a pressure of hot air present in a turbine compressor.
10. The purge process according to claim 1 , wherein the inert gas is nitrogen or carbon dioxide.