Pilot liquid fuel lance, pilot liquid fuel system and method of use

Abstract

A liquid fuel lance for a burner of a combustor of a gas turbine combustor, a liquid fuel system incorporating the liquid fuel lance and a method of operating the liquid fuel system. The liquid fuel lance has an elongate liquid fuel lance body and a liquid fuel tip. The elongate liquid fuel lance body includes a fuel flow passage and at least a first air passage and a second air passage. A liquid fuel tip defines a fuel outlet and arranged about the fuel outlet at least a first outlet and a second outlet to which air is independently supplied by the first air passage and the second air passage respectively, and wherein the amount of air supplied to the first air passage is variable.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is the US National Stage of International Application No. PCT / EP2015 / 074154 filed Oct. 19, 2015, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP14196154 filed Dec. 3, 2014. All of the applications are incorporated by reference herein in their entirety.FIELD OF INVENTION[0002]The present invention relates to combustion equipment of a gas turbine engine and in particular a pilot liquid fuel lance and a pilot liquid fuel system for a burner arrangement of the combustion equipment, and a method of operating the pilot liquid fuel system.BACKGROUND OF INVENTION[0003]Gas turbines including dry low emission combustor systems can have difficulty lighting and performing over a full load range when using liquid fuels. Often this can be because of fuel placement and subsequent atomization of the fuel in mixing air flows particularly at low loads and engine start-up. Idea...

AI Technical Summary

Benefits of technology

[0005]One objective of the present invention is to prevent carbon deposits forming on components. Another objective is to prevent carbon deposits forming on a fuel lance of a combustor. Another objective is to improve the reliability of igniting the fuel in a combustor. Another objective is to improve the entrainment of fuel droplets in an air flow. Another objective is to improve the atomisation of liquid fuel in a combustor. Another objective is to prevent liquid fuel contacting a surface within the combustor. Another objective is to reduce or prevent scheduled or unscheduled shut down of the engine for maintenance attributed to replacing or cleaning combustor components subject to carbon deposits and particularly the liquid fuel lance. Another objective is to increase the service life of the liquid lance. It is another objective to enable the fuel lance closer to the igniter and make ignition more reliable.

Problems solved by technology

Gas turbines including dry low emission combustor systems can have difficulty lighting and performing over a full load range when using liquid fuels.

If the fuel droplets contact a surface this can lead to carbon deposits building up or lacquers forming and which can alter airflow characteristics or even block air and / or fuel supply holes.

This liquid pilot injection lance is in a region prone to liquid fuel contact and as a result tends to incur carbon deposits.

These carbon deposits block the air assistance holes and subsequently prevent successful atomisation of the fuel.

Poor atomisation of the pilot fuel also causes problems with ignition of the fuel at start-up.

Further, carbon deposits can lead to liquid fuel being injected against the combustor walls or burn in the wrong place and which can lead to burn out of components.

This is a common fault with gas turbine fuel injection systems and carbon build up is a common problem.

This is undesirable because such replacement is expensive, causes the gas turbine to be off-line halting supply of electricity or power for example, and can be unscheduled.

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