Operation of a Fuel System Gas Turbine

Operation of a Fuel System Points : Operation of a Fuel System Gas Turbine Power Plant Fuel System Most large gas turbine are designs to operate with both gas and liquid fuels. The two most common fuels arc natural gas and no.2 fuel oil. Control system are provided allow automatic change ever from one fuel system to another or to allow burning of both fuel simultaneously.

The gas fuel system delivers gas fuel to the combustors at the correct pressure and flow rates for all operating conditions A strainer and on scrubber are normally to remove contents stop and control valve shutdown off the gas flow to the combustors. Whenever required for normal or emergency shutdown and controls the gas pressure in front of the control valve. The control valve meter the gas flow in accordance with the demands of the gas turbine.

An automatic vent valve’ is provided in vent piping between the stop and control valve. This valve relives any fuel gas. Between the stop and control valves to atmosphere instruments and control arc supplied to monitor the fuel gas flow and pressure and to alarm abnormal conditions The liquid fuel system delivers fuel to the combustion chamber nozzles. Fuel oil is normally delivered to the liquid fuel system under low pressure. Oil filters are provided at the inlet to this system to remove contaminants in the fuel supply. A liquid fuel stop valve is provided to shut off the supply of liquid during normal or emergency shut down. The valve is normally controlled from the hydraulic oil system Fuel oil pump increase the liquid fuel pressure to that requires by the combustion chamber. These pumps are sometimes driven by the turbine a accessory gear. A flow driver is provided in the supply lines to the combustion system to distribute the liquid hid to the fuel nozzles. A pressure valve is also provided on the discharge size of the pumps to prevent over pressure. The fuel delivery components in the event of a malfunction.

Liquid fuel sprayed in to the combustion chamber through the fuel nozzles forms. large droplets hat will not burn completely. A low pressure air at atomizing system is provided to break the liquid fuel stream in to a fine mist. The atomizing air source is an extraction connection from the compressor. The high temperature air must first be cooled to maintain a uniform temperature to the inlet of the atomizing air compressor. An atomizing air pre cooler uses water from the cooling water system. To absorbed the heat from the extraction air. The atomizing air compressors increase. The extraction air pressure to the level required to atomize the liquid fuel.

The main atomizing air compressor is driven by the turbine accessory gear. An electric motor operated starting atomizing air compressor is provided to supplement the main compressor during gas turbine startup.