0

Preventing Corrosion in Gas Turbine Fuel Systems FREE

[+] Author Affiliations
John E. Purcell

Roper Pump Company, Commerce, GA

Paper No. 97-AA-014, pp. V001T05A004; 9 pages
doi:10.1115/97-AA-014
From:
  • ASME 1997 Turbo Asia Conference
  • ASME 1997 Turbo Asia Conference
  • Singapore, September 30–October 2, 1997
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 978-0-7918-7867-5
  • Copyright © 1997 by ASME

abstract

Most failures of fuel system components, such as flow dividers and fuel pumps, are caused by the effects of corrosion. Rusting of iron and steel can jam rotating components, while surface pitting of many materials from traces of acids in the fuel can weaken parts. It can be shown that preventing fuel system corrosion can substantially increase the reliability and availability of the gas turbine.

Part of the reason that corrosion is such a problem in gas turbine liquid fuel systems is that most land based turbines operate most of the time on natural gas. This means that the liquid fuel system sits idle for most of the time. The liquid fuel almost always contains some water from sources such as condensation in the tank. Water also enters the fuel system from moisture rich combustion gases that can leak past check valves while the turbine is operating on natural gas. When the liquid fuel system is idle, this water separates from the fuel, collecting into a layer inside components. This forms an area of rust in the bottom of any unprotected component. This rust can prevent components from operating or can plug orifices and fuel nozzles downstream when the liquid fuel system is operated.

Corrosion in the fuel system can also come from traces of acid in the fuel. This usually comes about when operating on crude or residual oils with a high sulfur content. Water washing and heating of the fuel as part of the fuel treatment process may cause a chemical reaction that produces small amounts of sulfuric acid in the fuel. Over time, this acid may cause surface pitting in fuel system components. These pits can encourage and speed the formation of fatigue cracks in highly stressed parts such as shafts or bearings. These fatigue cracks will eventually cause the failure of these parts.

Two methods have been used to protect fuel system components against these corrosion problems. The first is to substitute inherently corrosion resistant materials, such as stainless steels, in place of existing materials. This is effective, but it is relatively expensive and creates lubrication and wear problems. These problems come from the poor wear characteristics of stainless steels and many other corrosion resistant materials when rubbing against other metals. Cathodic protection is the other method of protecting components against corrosion. This consists of introducing sacrificial anodes of a material, such as magnesium or zinc, that is more electrochemically active than frequently used materials such as cast iron or steel. The presence of these anodes reverses the corrosion process and makes the iron and steel parts the cathodic or protected end of the corrosion reaction. These anodes must be changed periodically since they are gradually consumed during use.

Copyright © 1997 by ASME
This article is only available in the PDF format.

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In