Zinc in Diesel Fuel or JP-5

[NeilDS]

On a project I am working on, a concern has been rasied about the effects of zinc in Diesel Fuel or JP-5 would have on the fuel system and engine wear of our Diesel Generators (1+ MW). Some of the fuel storage tanks also can funtion as water balast tanks and have zinc anodes installed in them. The engines do not pull directly from that tank and the fuel has to go through a filter seperator before going into the engine fuel feed tank. My understanding is that zinc can react with the sulphur in the fuel and form zinc sulphide or sulphites. This would cause a gum that might effect the fuel system. I would think the this would be caught by a filter seperator system? Are there any other known issues with zinc geting into fuel and causing engine damage from blow-by and zinc getting into the crankcase? I know that zinc is an oil additive so I am not sure how a small amount of zinc from blow-by would cause a wear issue with the engine. Is it possible that after the zinc has been trhrough the combustion chamber that it has now become harmful? Any thought or experiences with this would be most helpful. Thanks!

Neil

 

[swall]

NeilDS--Whether or not the separators will catch the zinc residue depends on how fine of material they are designed to capture as well as how the residue will agglomerate into larger clumps. I can't speak to diesel fuel, but I did experience a zinc issue with automotive (glycol type) brake fluid. This was in an anti-lock system, and some of the filters were very fine (can't remember the size, but am guessing around 40 microns). What happened was that zinc, in the form of zinc stearate, came out of the system hoses and then agglomerated due to the presence of a silicone based assembly fluid.The resultant sludge plugged filters as well as metering orifices.