Generators, aviation fuel to diesel
Generators, aviation fuel to diesel
(OP)
Hi All
I am in need of some assistance as i have been asked a curly question by my son and need help to answer it. Please forgive the ignorance in the question he asks
We've got some generators only small ones) that are currently running on jet aviation fuel (kerosene). We want the generators to run on deisel instead. Is this possible. Are diesel engines similar to kerosene engines?
1.Can the engines be converted to diesel??
2. How much work/rework is involved
Thanks
Lindon
I am in need of some assistance as i have been asked a curly question by my son and need help to answer it. Please forgive the ignorance in the question he asks
We've got some generators only small ones) that are currently running on jet aviation fuel (kerosene). We want the generators to run on deisel instead. Is this possible. Are diesel engines similar to kerosene engines?
1.Can the engines be converted to diesel??
2. How much work/rework is involved
Thanks
Lindon





RE: Generators, aviation fuel to diesel
RE: Generators, aviation fuel to diesel
RE: Generators, aviation fuel to diesel
We are doing a study for a very remote site where there is very little doumentation available. We have a site visit booked but at the moment, all I have to go on are some photographs and a P&ID.
The generator sets are only about 50kVA so reciprocating engine. They are currently running on AVTUR-FSII. I don't have information on the manufacturer.
I have little knowledge of diesel engines but I suspect that these are actually normal diesel engine generator sets running on AVTUR.
Do my suspicions sound feasible? Can a reciprocating diesel engine run on AVTUR without major modifications? Can these generator sets run on diesel after running on AVTUR?
Any assistance will be appreciated.
RE: Generators, aviation fuel to diesel
The two most common issues faced, at least in my experience,
1. The aviation fuel has a lower BTU per gallon/liter than "standard" diesel. Some manufacturers allow the change in fuel stop setings to allow a higher fuel rate if light fuels were used. If it was running on light fuels and now you want to change, you need to assure the fuel settings don't allow for too much fuel or you may overload the engine.
2. The aviation fuels had lower lubricity and some steps may have been taken to either provide extra cooling or something else to help prevent fuel system problems. If you're doing a site visit take a careful look at the existing fuel supply system and make sure it meets the engine manufacturers guidelines.
In some rare cases I have run across engines that have had minor fuel injection timing changes, so when you do change the fuel type, assure the engine does not smoke excessively , or have any other operational issues.
If you can find details on the model of the engine and it's power rating, the manufacturer can provide you a fuel specification on the preferred and allowed fuels the engine can operate on.
Hope that helps,
Mike L.
RE: Generators, aviation fuel to diesel
Great response. Exactly what I needed to know.
RE: Generators, aviation fuel to diesel
Good luck on the investigation. Remember too, that automotive diesel has changed a lot too since these engines were put in and set up (assuming they aren't very new.)
The de-sulphurized diesel of today (if that is what you are in to) also has lower lubricity than the old stuff.
rmw
RE: Generators, aviation fuel to diesel
RE: Generators, aviation fuel to diesel
As a note small engines have been converted to run on kerosene using SI. But the low octane of kerosene requires a compression ratio reduction.
RE: Generators, aviation fuel to diesel
With a petrol engine the compression ratio's range generally from 8 - 12. Diesel's work on compression ratio's from 14 - 25. What compression ratio can a kerosene injected motor operate safely and economically. Will the generators/ motors need to have their CR upped? Will there be detonation/efficiency issues?
RE: Generators, aviation fuel to diesel
The problems with alternate fuels are more related to viscosity, impurities, and lack of lubricity. Oh and also maybe required a:f for maximum power and tendency to leave undesirable deposits behind.
Regards
Pat
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RE: Generators, aviation fuel to diesel
RE: Generators, aviation fuel to diesel
I used to work quite a bit with smaller power plants in the Pacific, some in the Carribean, and in Central and South America, all mainly CAT powered plants, but many mixed power stations as well.
I was amazed by some of the things I saw used for fuel. On one island they had 12,000 gallons of old gasoline, 20,000 gallons of contaminated jet fuel and a basement full of used lube oil with some hydraulic oil mixed in. The plant operator mixed this stuff with #2 diesel fuel every day and topped off the day tank for two CAT D399 engines, they smoked, they hammered but they ran and used up the junk I'm not sure how else they would have gotten rid of. One of the other engines on site was a 567 series EMD, it was mistakenly fed this witches brew one day, ran about an hour and stuck several injectors. Now that old EMD was a tough engine, there are many competative products I came to admire over the years, but it's fuel system could not tolerate the change in lubricity and the engine smoked terribly before it stopped, likely due to the much lower cetane rating of the mix.
Another site mixed rancid palm oil with diesel and jet fuel (also contaminated) and ran it in two older engines, one CAT and one Blackstone until it was all used up, they killed a newer CAT 3412 with the fuel, again a fuel system failure that resulted in a burned piston.
In general I've found lower BMEP engines with pintle (single hole)fuel nozzels and precombustion chamber fuel systems very tolerant to fuel quality changes. Direct injection engines with higher BMEP and fuel injections pressures become much less tolerant. Lighter fuels tend to burn more completely and have less cylinder deposit issues, but can cause more fuel system component failures. Heavier fuels usualy need more air to burn completely and tend to form more cylinder deposits, but their fuel system component life, if the fuel was properly filtered, was about the same as using #2 diesel.
Before I left the CAT dealer I worked for we did a turn key plant for the Pacific that included one used PC type engine rated smaller than the new units, but mainly provided to burn diluted waste lube oil to dispose of it, the engine only runs about 2000 hrs/year but keeps using up the waste oil.
Mike L.
RE: Generators, aviation fuel to diesel
HUH????
Kerosene is often mixed with diesel in colder climates in the northern USA to produce what he refers to as #1 Diesel when true #1 diesel isn't available. The resulting lower pour point prevents fuel system jelling at the lower temps. But that blended #1 diesel of the automotive (trucking) world is still a certain proportion #2 diesel usually at least 50%.
Pure #1 diesel can be produced at the refinery and is made by setting the beginning and end points of the distillation process at the appropriate temperatures, but it requires a change to the process so you better be ready to make a lot of it at once. For smaller quantities it is easier just to blend some kerosene to obtain the desired pour point during the coldest months or during surprise cold snaps.
And yes, as an unscientific observation, the truck drivers I employed back in the day bitched because the #1 didn't produce as much power as straight #2 diesel. They loved their horses.
I once lived near a terminal on a products pipeline in the deep south, and from time to time during the summer if you didn't pay attention to where you fueled, you would be buying fuel pulled from the pipeline that was the winter diesel on its way north (during the summer) for next winter's use. That was in the days before coloring was forbidden and you could always tell when you had gotten winter diesel because it was nice and red. It ran like crap too.
It was the opposite in the winter. You could get a load of (the north's) next summer's straight #2 fuel being shipped during our winter. I generally tried to fuel from stations I knew obtained their diesel from local refineries since they were blending more for the local climate. My day job at the time took me into local refineries as well as the pipeline terminal so I knew which tanker fleets loaded where.
Kerosene is more akin to jet fuel grades, and those obviously can't be allowed to gel at the temps found at 30K feet altitude. Ironcially, on my day job I work with industrial jet engine turbines designed to run on #2 if they have a liquid fuel option and they won't run on jet fuel grades - different burners than their aircraft engine cousins.
And, to Mike L's point, I have personally mixed gasoline with lubricating oil in a Ford 7.3 IDI engine on more than a couple of occasions in order to be able to make it just a few more miles to a diesel fueling station without any noticable or lingering problems. Really get some stange looks from 'stop-n-rob' clerks when you buy a couple of gallons of gasoline and 4-6-8 quarts of oil and that was the total sale.
I regularly mixed ATF with diesel as a water absorbent and did that in Cummins, Ford and Detroit Diesels that I have owned. (Sorry Mike, I never owned a Cat.) Seems the dispersants in ATF are excellent in emulsifying water in diesel, better in some cases than the commercial products as observed by some unscientific testing I did in my garage.
The first truck driver that turned in a receipt for several quarts of ATF that he told me he put in the tank to get rid of water took me by total surprise. I was quite the skeptic until I ran the aforementioned test.
Back when I drove diesel vehicles (sold my last one 5 years ago) I rarely changed a fuel filter that I didn't fill it with ATF rather than diesel. Hated that stench of #2 on my hands.
rmw
RE: Generators, aviation fuel to diesel
rmw why the hum? Its a true statement. We are talking the CI world not SI.
RE: Generators, aviation fuel to diesel
rmw
RE: Generators, aviation fuel to diesel
For all the years I worked at a CAT dealer, on-road diesel, mostly #2 was the preferred fuel. My first experience with an engines owner not wanting to use diesel fuel came from a site that was a remote military base with the primary fuel stock on the island being jet fuel for helicoptors. They burned more gallons per hour than they would have with diesel, but didn't have the concerns of accidentally mixing fuel and causing other potential problems for the aircraft.
From some old operating literature, fuel used to account for 75% of the 10 year life cycle cost of a typical high speed diesel engine. With shortages, desire to use waste streams, reduce logistical concerns and complexity, or just to save a buck or two I'd expect that people will find a broader range of stuff to feed their engines with, at least till the air board folks get wind of it.
Mike L.