Fuel system materials?

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Fuel system materials?

Postby Radrick » Thu Apr 03, 2008 4:47 pm

So in the Polymerization thread Sun shows that copper, brass, tin, lead, and steel all react with wvo and can cause problems, yet the fphe's, heated tank pickups and fuel lines that many people are using are copper? Should I be concerned about using copper in my fuel system or is it ok do to the lack of air and water in the system? I have a good source for sheet stainless steel, is it worth building the tank our of stainless? In that thread it also states that to large of a tank is bad. I am planning on building a 110 gallon tank, this will last me approximately 3 weeks. Is 3 weeks to long? Thanks in advance for the feedback.
1995 Chevy K1500 6.5 TD not on WVO yet but soon.
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Postby SunWizard » Thu Apr 03, 2008 10:14 pm

Those metals are no problem except in your tank, due to no air or water, as long as you have a looped return on VO. Yes stainless tanks are good, so are plastic and aluminum. 3 weeks isn't too long if you don't heat your tank >100F repeatedly. And it depends on how oxidized your VO is when you put it into your tank, and type of VO.
YVORMV - Your veg. oil results may vary.
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81 Mercedes 300D- stock and happy on V80/D20 blend.
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Postby Welder » Fri Apr 04, 2008 4:16 am

SunWizard wrote:Those metals are no problem except in your tank, due to no air or water, as long as you have a looped return on VO. Yes stainless tanks are good, so are plastic and aluminum. 3 weeks isn't too long if you don't heat your tank >100F repeatedly. And it depends on how oxidized your VO is when you put it into your tank, and type of VO.


Okay, this question will best belong in the polymerization thread, but because I though of it while reading this thread, I'll ask it here:

Sun, you mentioned that "it depends on how oxidised your VO is when you put it into your tank". I'm wondering if the polymerization process is chronologically linear based mostly on existing oxidative damage, or whether there's some sort of threshold for oxidation that exponentially increases or expedites polymerization.

I know that was a mouthful and I might not have worded it too clearly, so I'll try to say it differently:

If heavilly oxidised WVO were added to a heated veggie tank, or added to an unheated veggie tank with a full-return-to-tank fuel line, is there anything that can be done to reduce or delay the progression from oxidised oil to vegpoly (chicken skin)? I mentioned a heated tank and/or a retur-to-tank fuel line because I wanted to throw the heat factor into the equation.

Basically, I'm asking if antioxidant additives help prevent vegpoly AFTER the WVO is already oxidised? If not, does anything else? I've been advised by a bunch of chemists that aside from antioxidants, adding chelators may help prevent vegpoly by dropping metal ions out of the veggie.

I'm guessing that if we assume oxidised oil from the start and then insist on heat in the veggie as another obstacle, then the only other variable we have left to play with is time. I guess that's why the issue of tank size came into the conversation.

Is there any evidence that adding antioxidant additives to heavilly oxidised oil helps prevent vegpoly?

How big of a factor is time in dealing with heavilly oxidised oil?

How big of a factor is heat in dealing with heavilly oxidised oil?
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Postby Radrick » Fri Apr 04, 2008 7:04 am

SunWizard wrote:Those metals are no problem except in your tank, due to no air or water, as long as you have a looped return on VO. Yes stainless tanks are good, so are plastic and aluminum. 3 weeks isn't too long if you don't heat your tank >100F repeatedly. And it depends on how oxidized your VO is when you put it into your tank, and type of VO.


thanks Sun. I will build the tank out of stainless. I was pretty much planning on that anyway. You will probably get a kick out of this, I went and measured a friend of mines dodge last night. If I am going to go to all the work of building this fancy stainless tank I want it to fit a dodge to just in case. :lol:
I will have a looped return I can't imagine why I would want anything else. I am having a hard time deciding where i should locate my vo pump. I am using a second stock pump and they are normally located on the frame rail. I know that it is easier for the pump to push fluid than it is to suck it so closer to the tank is better, but I sure would like to put it in the engine bay for ease of install. I am planning on having two HiT or TiT loops. One from pump to fphe and one from pump to heated pickup. I will close the rear one in the summer and regulate it with a ball valve on the floor board in the winter. This way I can keep the vo warm but not hot.
1995 Chevy K1500 6.5 TD not on WVO yet but soon.
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Postby SunWizard » Fri Apr 04, 2008 8:38 am

Welder wrote:... or whether there's some sort of threshold for oxidation that exponentially increases or expedites polymerization.

Its a chain reaction which increases exponentially beyond a point.

Welder wrote:Is there any evidence that adding antioxidant additives to heavilly oxidised oil helps prevent vegpoly?
How big of a factor is heat in dealing with heavilly oxidised oil?

Yes TBHQ works to stop poly even in progress. Heat is a large factor, the amount of oxidation doubles with every 10C increase. See the poly thread.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
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Postby Welder » Fri Apr 04, 2008 3:16 pm

Thanks Sun.
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Postby Burbarian » Fri Apr 04, 2008 4:57 pm

On the subject of antioxidants and lard.

Does lard polymerize at the same rate as regular vo?

SunWizard wrote:3 weeks isn't too long if you don't heat your tank >100F repeatedly.


Heating this fuel to 100F is going to be: Every time you start up and use the vehicle, unless you decide to run on dino and have a TIH coolant circulation cutoff valve.

At this point, I don't know whether to be more concerned about potential polymerization or of winding up with a tank full of warm animal fat going rancid and becoming a rotting microbial buffet.

And if the stuff goes bad, the smell can be unimaginably worse.

I expect that with lard, as with all vo fuels, serious dewatering is necessary. Not just for the IP and injectors sakes, but also to reduce polymerization and to curtail or at least retard the rate of microbial infestation.

If lard polymerizes at a fair clip, then it would appear one should use a small tank, and to use up the stuff as quickly as possible in small batches unless one is going on a long trip. Or if using a large tank, to use antioxidants as a given requirement in order to combat heat-accelerated polymerization.

If lard does not polymerize, or does so at a slow rate even when subjected to >100F temperatures on a regular basis, then going the opposite thermal route may be viable: Get it to at least 180F and preferably 210F to deep fry the little microbial buggers. That way they won't propagate, because they've become teeny crispy critters.

Basically, heat sterilization. Once the engine is up to temperature, change from loop to return-line and you fry any buggers in the FPHE with hot coolant and return sterilized lard to the tank. Microbe population control, as it were. No need to heat the entire tank. At 60gph, you cycle the contents of a 20 gallon tank through the FPHE sterilizer 3 times in one hour.

Of course, this hinges on the polymerization characteristics of lard, and I am probably missing something.
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Postby SunWizard » Fri Apr 04, 2008 5:15 pm

Burbarian wrote:Does lard polymerize at the same rate as regular vo?

Lard doesn't poly much since its saturated fat, like PHO.

Burbarian wrote:Heating this fuel to 100F is going to be: Every time you start up and use the vehicle, unless you decide to run on dino and have a TIH coolant circulation cutoff valve.

Thats why most use only a heated pickup. My heated pickup never heats the entire tank above 100F, unless its already 90F ambient.

Burbarian wrote:Basically, heat sterilization.

Thats not hot enough for sterilization. It might make any microbes get even stinkier, which is a problem with lard: the dead, decaying animal smell.

This belongs in the poly thread, I will move it later.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby Burbarian » Fri Apr 04, 2008 7:40 pm

Excellent and valuable information as always. Thanks, Sun.

Ok, considering the low polymerization rate/susceptibility of lard, then my current materials selection and fuel tank/TIH design would be as follows:

Going with an TIH design similar to what Welder was considering. Copper tubing, 3/8 or 1/2 OD as per Sun's positive experience.

50ft roll 3/8 copper tubing from ebay. $45

Copper tubing brazed/soldered to brass fitting ends, then mounted to stainless heated in-tank pickup with removable SS strainer. Stainless instead of aluminum to minimize contact galvanic corrosion. Loop with return to small 1 gallon heated and sealed purge/switch tank to minimize standing fuel that's run through copper lines. Also limits amount of lard in the main tank that actually need to be heated. This gives flexibility in using other vo fuels in addition to lard, which may have a higher poly risk.

50ft roll of 3/4 heater hose from AutoZone for $44
http://www.partsamerica.com/ProductDeta ... Code=3604A

Polymer vo/lard tanks insulated with construction blueboard.

Possibly fill the 2ft long removable heated in-tank strainer with silica gel crystals as cheap insurance against condensation moisture. Testing shows it to be quite effective at removing water from vo.

Possibly blend the lard with something nasty. Perhaps a pint of mineral spirits, paint thinner or acetone per 10 gallons of lard. Or blend with gasoline. Unless I am mistaken, the 'rotting dead animal smell' of spoiling lard is due primarily to gases given off by microbial decomposition, so making the stuff microbe-unfriendly should mitigate that.

As always, comments and criticism highly valued. Current design subject to revision.

Thanks
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