Fuel Related Questions ~ Biodiesel WVO

[Curt]

Is anyone here using waste vegatable oil or biodiesel for to power their trawler or motorsailer?

[klem]

I have experience running biodiesel in a few boats but never WVO in a boat, only cars. Basically, you need to be careful about the same things as cars. The fuel will eat natural rubber so you can't have any in your fuel system which on a lot of boats will mean replacing the fuel lines. On older engines, there was a lot of natural rubber in the engine's fuel system which means that it isn't a good idea in general. If you are mechanically inclined, you can replace everything with something like Viton. Then again, if you are not mechanically inclined, running any of these fuels isn't a great idea.

Something to watch for with biodiesel is that it tends to break stuff loose in your fuel system and you will plug your filters shortly after starting to run it. This isn't a big deal provided that you plan to change them approximately twice early on and then at the normal interval after that.

Temps don't tend to be an issue on boats since people don't use the boat when it is cold enough for biodiesel to gel. If you are someone who runs your boat at below freezing temps, you should pay attention to this.

The biggest benefit from running blended biodiesel (I have tried many variations from B10-B100) is that at a moderate blend, the exhaust fumes are much less noticeable. I really feel that this made a difference with people getting seasick on long, foggy, rolly days.

WVO is a much bigger commitment and you really have to like tinkering and getting covered in nasty grease. If I regularly negotiated dangerous stretches of water, I would think twice about it or have multiple sets of filters in parallel that I could switch between. If you go WVO, you need to be really careful to keep the mess isolated to the engine room and not the whole boat. Depending on your cooling system, you might have to think about how you are going to heat your wvo tank. Marine tanks also tend to be quite large so it would take a long time to heat the whole thing and one of those drop in fuel sending unit heaters might make a lot more sense.

I hope that this helps.

[ffiill]

Blending is a viable option but just with biodiesel or staight veg oil in my opinion depends upon your motives?
Here in the UK with keroscene and diesel having almost doubled in price in last couple of weeks to just under £1 uk per litre! and Supermarket veg oil at just over £1 per litre veg oil is now on the cards.
However just as in my central heating tank to which I add used fltered veg oil to keroscene all I am prepared to do is blend in about 25%.
If as I suspect in US diesel prices remain low then why bother?
Also if you primarily sail then cost of fuel not that important.

[RichH]

I have considerable experience with 'bio-diesel" especially blends that are from 'reclaim' (cooking oils, etc.).

If you keep the 'blend' to no more than 10% bio-diesel or 'reclaim', chemical compatibility usually is no problem, 15% being the upper limit. This will insure that the typical Buna/Neoprene elastomers of hosing, valve seats and diaphragms, etc. will (somewhat) stay integral for beyond 'short term exposure'.

Beyond 10-15% one really needs to consider Teflon, elastomeric teflon co-polymers, or Viton; .... this includes changing from polypropylene to nylon, UHMWPE, etc. for tankage, etc.
For 'reclaim', that is co-contaminated with oleic and other organic acid forms use only Teflonics (PFA, PTFE, ECTFE. etc.). This includes engine crankshaft, etc. seals, etc. as the normal engine blow-by containing oleic, etc. acid will also soon soften/destroy the Buna/Neoprene engine lube-oil seals, seals on common lube oil recirc. filters/filter housings, oil pan and valve cover gaskets, etc. etc. Also keep the intake (and to some extent exhaust) valve seals under close scrutiny, especially if the 'wiper' section is of OEM BUNA/Neoprene.

10% bio-diesel usually isnt a problem; greater than 15% usually requires quite expensive 're-sealing' and re-gasketing. If using 'reclaimed' cooking oils, the oleic acid component can, on long term, attack the OEM polymer seals, etc. as low as 5% if the fuel is stored/heated to much above 30°C.

PTFE/PFA/ECTFE based or Viton seals are horrendously expensive in comparison to the standard BUNA/Neoprene. PFA/PTFE seals also require perfectly smooth shafting journals, etc.

;-)

[ffiill]

Much of what is being discussed here is very much engine dependant and I would suggest relates to useage in modern high pressure common rail computer controled engines.
Remember Mr. Diesels origional engine was designed to run on peanut oil as he saw it as a solution to providing a power source in third world situations.
My Mercedes OM636 according to its workshop manual will quite happily run on vegetable oil;palm oil etc.This is of course helped by the simple inline fuel injector pump as opposed to a rotary pump or high pressure common rail pump.
For anyone seriosly interested suggest you read
From the fryer to the fuel tank-J.Tickell

[svHyLyte]

Originally Posted by ffiill

...Remember Mr. Diesels origional engine was designed to run on peanut oil as he saw it as a solution to providing a power source in third world situations.

True. Remember, however, that Mr. Diesel's original motor also relied on copper o-rings and seals that were not subject to disolution as are the seals and o-rings on modern engines.