emulsify or demulsify water in diesel fuel?

[Bill Plock]

Hi, I'm new to this forum and have found it very informative. Thanks!

I have been driving diesels since 1985 and always have used a fuel supplement. Recently on another diesel related forum I learned that there are two different methods for treating water in diesel fuel. Some diesel fuel additives demulsify water while the others emulsify or disperse water.

Anyone have insight into the trade-offs between these two approaches to handling water in diesel fuel? The demulsifier vendors imply that emulsified water can come out of suspension at the wrong time and cause problems. But the demulsified fuel could also cause water to collect in the bottom of the fuel tank and provide the opportunity for algae to form (?). On the other hand, emulsified fuel "locks up" the water to prevent water in the tank. But how well is the water locked up? Can it come out of suspension in the injection pump under certain conditions (cold weather/high pressure) and cause erosion?
I don't mean to imply one product is better than another - just curious about the technical differences in the two approaches to dealing with the problem of water in diesel fuel. Any insight would be greatly appreciated...

 

[Bio-T]

Bill,

This argument has been going on for longer than I can remember in various forms. I use a different take on the situation, I don't want the water in the tank to cause algae and I don't want it going through my injectors either. So I use emulsifiers and move the water from the tank to my primary fuel/water separator, and from that to the engine fuel/water separator and hope that the encapsulation of water is minimal when it goes to the injectors after 2 fuel water separators.

The primary use of diesel additives is to make sure that you don't have any alcohol and has good lubricity. When I use an additive if I don't have any water in the primary fuel/water separator then I know I have the wrong additive.

I have used Schaeffer's Diesel Treat 2000, Shaeffer's Soy Shield, Neutra 131, Power Service White and Grey bottle, Lucas, Howe's Meaner Cleaner, Shell DFA, FP (Fuel Power), Stanadyne, and a few others.

 

[Neil Womack]

Bill

I saw a very heated argument in tdi site on the very subject of water in diesel fuel. Lots of sizzle and smoke but no clear winner. When in doubt do what the manufacturer tells you.

In the case of Volkswagon and John Deere ( the only two I've researched ) they say use Stanadyne Diesel Fuel treatment ( repackaged as John Deere diesel fuel treatment at your local JD dealer).

I think Stanadyne is in the emulsification camp.

[ June 06, 2003, 10:59 AM: Message edited by: BOBISTHEOILGUY ]

 

[Bill Plock]

Interesting story in the April issue of GM TechLink regarding Diesel Fuel Additives.

http://service.gm.com/gmtechlink/images/issues/cnt_mo/TLcme.html#story1

[ April 13, 2003, 09:54 AM: Message edited by: Bill Plock ]

 

[Ken2]

The algae or bacteria or bugs or whatever, in addition to clogging filters, is acid (smells like rotten eggs--hydrogen sulfide) and can damage fuel injection equipment. It grows on the fuel/water interface, so a water-free tank is very important.

There have been on-going attempts to use fuel/water emulsion. The advantage of a proper emulsion is the water droplets flash into steam in the hot combustion chamber and improve the atomization of the fuel for better combustion. The drawback is a loss of lubricity which can damage the fuel pump. Mechanical emulsifiers have been sold for years for large engines burning heavy fuel. Chevron and Lubrizon have been working on a chemical emulsion project where the water droplets are surrounded with a chemical material that lubricates and maintains the emulsion preventing the droplets collecting into bigger drops. Who knows if we'll ever see it marketed?

An alcohol-free additive that emulsifies small amounts of water but allows larger amounts of water to be captured in the separator would be great?...anything on the market do that?


Ken

 

[mojo]

Regarding the waater emulsification, Lubrizol has started to market their fuel called Purinox which is somewhat similar to what Chevron is doing in CA. What they are supplying is a 10% or so fuel in water emulsion where the emulsifier causes the water droplets to be surrounded by the fuel. This is referred to as a fuel-in-water microemulsion. That is why the fuel appears to be clear and not white as would be the case in a water-in-fuel microemulsion.

 

[Steve S]

I have seen lots of diesel fuel systems full of the biological stuff that grows in the feul ,don't know what works best but use something on a regular basis ,but there is no need to go over board or over dose. There are also biocides that kill the little critters which is the best if there is a problem already and then use a cleaner that does something for the water.

[ April 13, 2003, 12:33 PM: Message edited by: Steve S ]

 

[Bill Plock]

Heres a recent publication by Stanadyne on this subject.

Marketing Bulletin #MB 2059, May 2003

 

[widman]

I am in the emulsify camp. I use a product that is called "Diesel Plus" in the States (Diesel Power here since someone had used the name). It eliminates black smoke, eliminated injector pump problems (used to be every 9 months in each diesel vehicle)and basically eliminated rust and water problems. Without the additive my water/filter alarm in the 4Runner went off every 4,000 to 5,000 km, and I had to replace the filter by 6,000 km. Since I started using the additive (16 months ago) I run 24,000 km between filter changes and have never heard or seen the alarm again.

 

[Ken2]

Schaeffer's diesel fuel additive seems to do both jobs:
--"Allow moisture to be rapidly separated from the fuel.
--"Dispersion of water present in diesel fuel in order to prevent fuel icing and other problems associated with water."
http://www.schaefferoil.com/data/137.htm

"Dispersion" sounds to me like allowing very small droplets of water to pass through the filter and the engine.

If I get a chance, I'll ask a Schaeffer chemist just what this does mean, and if both jobs, how they do it.


Ken

 

[Bill Plock]

Ken2,

A Chemist's explanation would be excellent. I can see the pros and cons of both methods of handling water in diesel, but an unbiased technical explanation of the chemistry would be much appreciated.

[ June 08, 2003, 07:06 AM: Message edited by: Bill Plock ]