Polymerization in WVO

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

Moderators: SunWizard, coachgeo

Postby Burbarian » Sun Mar 23, 2008 8:42 am

David wrote:What occurs to me is if oil is polyed up from air drying ( or heat or anything else that people claim causes it) and goes through the fuel system and burns fine in the engine as mine does If it is polyed at all, is there anything to worry about in the first place?


The concerns might be resumption of accelerated polymerization once the fuel has been introduced into a steel vehicular fuel tank (specially oversized tanks or infrequent use causing the fuel to sit for weeks or months), the increased viscosity as compared to unpolymerized oil, potential increased wear on the IP and injectors, and earlier filter plugging. Note that these concerns are currently still theoretical, and based on your experiences, may be negligible. However, in cold climates the effects might be aggravated, primarily due to quite significant amounts of daily temperature driven condensation in metal tanks introducing water into the fuel. Likewise, some vehicle engines may be more sensitive.

We know that poly can grow so large as to form visible sheets (chicken skin) so it is certainly possible for flakes to plug a filter, or smaller flakes to get by say a 10 or 25 micron filter and accelerate IP and injector wear. CAT recently recommend using 2 micron absolute filters for their IPs in order to prevent premature wear.

Anybody know if polymerized oil has a different gel temperature and whether it is caustic?
Burbarian
 
Posts: 195
Joined: Wed Mar 05, 2008 12:14 pm
Location: Vermont

Postby SunWizard » Sun Mar 23, 2008 11:29 am

The oxidation process that creates poly also creates acidic suspended water. So if you store in a barrel for a long time and it gets poly and you don't do a hot pan test on it you could be at risk. Same thing if you have a poly paint smell coming from your vehicle tank if its too large, and heated too much or too often before the VO is consumed.

This is a worse problem than the other one: plugging your filter.
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.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby SunWizard » Sun Mar 23, 2008 11:46 am

David wrote:In MY experience, water seems to be a required factor in making poly.

I have made lots of poly without water. The amount of oxygen is the main factor I have found. I think water is a good transporter for oxygen to enter the VO, and it works from below and within while the air works from above.
David wrote:My predictions:
Dry oil in contact with steel will do nothing at all except attract bugs and flies.
Dry oil with water will chicken skin but I'm leaning towards little if any rust on steel surface.

I have gotten lots of chicken skin poly in steel barrels with no water, but with lids that didn't seal tight so they got air. Or in ones that were less than half full yet tightly sealed so they had lots of oxygen available for poly formation. Remember the oxidation process itself creates water and acid, even if the VO was very dry to start with.

For "Raw oil, I'm predicting chicken skin and some rust of drum although not much as I know this oil is probably a hell of a lot dryer than what a lot of people happily put in their tank.

I take shots and post up the results.

Sounds like a good project.
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.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Chickenskin on teflon

Postby JohnO » Sun Mar 23, 2008 9:45 pm

My oil dryer is a teflon-coated skillet, with a copper tubing heat exchanger. All outside Teflon surfaces of the skillet are coated in chickenskin, as is the inner teflon surface ABOVE the oil. There has never been any indication of chickenskin anywhere other than at the oil/air interface, after a few years use. I would be very surprised to learn that the Teflon has anything to do with polymerization, other than to provide a surface.

The oil is presumably still "wet" as it passes through the copper tube heat exchanger, reaching 120C as it enters the bottom of the skillet. Although residence time is short (less than 1 minute), the whole purpose of the device is to expose the hot oil to the air in a very shallow layer (less than 1/4 inch deep over the dividing plate) before it flows back through the heat exchanger to preheat the arriving oil. I'm thinking I should calibrate a Tilly-style viscometer to check for signs of polymerization, but frankly I see little to no indication. According to some of my reading, the "paint" odor precedes the viscosity change by quite a bit, and my dryed and filtered oil stored for a year in plastic still smells "fresh".

My reading of old methods for making boiled oil paints requried the oil be boiled with metal IN THE OIL, not in water under the oil. Also, the boiling ws of the oil not water, so the temperature was really hot (450F and higher) and went on all day for just a small batch. That initiated the polymerization that allowed the paint to dry in reasonable time (days to weeks) in a thin layer on canvas. While instructive, it also suggests that many of our concerns about fuel polymerization are overblown.
Cheers,
JohnO
JohnO
 
Posts: 6
Joined: Wed Mar 05, 2008 7:30 am
Location: Moses Lake, Washington

Oxidation

Postby leftcoastjeff » Sat Apr 26, 2008 11:54 am

When I was working at a micro-brewery in learned a lot.
One thing is that in fermintation, the beer makes CO2, which forms a barrier on top of the open container, preventing contamination and oxidizing.
Could CO2 do the same for the "chicken skin" problems?
'87F-250 stock, minus that pesky water seporator/air inlet, bone stock for now.

Thomas Edison says it best, “Opportunity is missed by most people because it is dressed in overalls and looks like work”.
leftcoastjeff
 
Posts: 196
Joined: Thu Apr 17, 2008 6:35 pm
Location: Monterey, cal.

Postby SunWizard » Sat Apr 26, 2008 11:59 am

Yes it could, and the commercial VO companies fill the headspace in their barrels and jars with any inert gas that can displace the oxygen. For my use I find its simplest to fill the barrel to the top, and then keep it tightly sealed. If you can't fill to the top, then adding a gas should work as long as it can displace all the oxygen. It seems like it would be hard to tell when you have it all displaced.
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.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby zoochy » Sat Apr 26, 2008 1:36 pm

Carbon dioxide is heavier than oxygen so as long as you slowly inject the CO2 it will displace the oxygen.

A simple test for the presence of oxygen is to move a burning match into the top of the container. If it extinguishes, there is no remaining oxygen.
91 Toyota Hiace 3L engine w/ a 300W ½” heated fuel line, lift pump, additional 10um fuel filter, and a 2nd diesel tank for starting.
>160,000 km on:
88% canola WVO
11% old gasoline
.6% turpentine
.3% acetone
.1% eye of newt
zoochy
 
Posts: 66
Joined: Fri Mar 07, 2008 8:21 pm
Location: Victoria, BC, Canada

CO2

Postby leftcoastjeff » Sat Apr 26, 2008 1:46 pm

I wonder if you could set up your oil tank with a little positive pressure from a CO2 cylinder with a regulator that delivers as fuel is used?

Couldn't hurt, no oxegen, less poly?

Maybe "push" oil too.

LCjeff
'87F-250 stock, minus that pesky water seporator/air inlet, bone stock for now.

Thomas Edison says it best, “Opportunity is missed by most people because it is dressed in overalls and looks like work”.
leftcoastjeff
 
Posts: 196
Joined: Thu Apr 17, 2008 6:35 pm
Location: Monterey, cal.

Re: CO2

Postby coachgeo » Sat Apr 26, 2008 3:33 pm

leftcoastjeff wrote:I wonder if you could set up your oil tank with a little positive pressure from a CO2 cylinder with a regulator that delivers as fuel is used?

Couldn't hurt, no oxegen, less poly?

Maybe "push" oil too.

LCjeff
Believe that most tanks set up for Veg and diesel are vented to allow the return lines from the engine area to send air back along with fuel in the return. The air makes it's way out the vent as would the C02
Life; It's all in the Balance

Moderator
coachgeo
 
Posts: 569
Joined: Thu Mar 06, 2008 10:46 am
Location: North Texas

Postby rkpatt » Sat Apr 26, 2008 3:55 pm

Filling the headpace with exhaust from the engine to displace the oxygen. This is done on large storage tanks before they cut a hole in them with a torch or chopsaw .
rkpatt
 
Posts: 61
Joined: Thu Mar 06, 2008 5:32 pm
Location: GA

Postby rkpatt » Sat Apr 26, 2008 3:56 pm

What about filling the headpace of the barrels with exhaust from the engine to displace the oxygen ? This is done on large storage tanks before they cut a hole in them with a torch or chopsaw .
Last edited by rkpatt on Sun Apr 27, 2008 7:51 am, edited 1 time in total.
rkpatt
 
Posts: 61
Joined: Thu Mar 06, 2008 5:32 pm
Location: GA

Postby leftcoastjeff » Sat Apr 26, 2008 4:18 pm

Is exhaust denser than ox, CO2 is and its got less extra particulate
That's a great way to cut possibly flammible closed containers, other than fill with water.
'87F-250 stock, minus that pesky water seporator/air inlet, bone stock for now.

Thomas Edison says it best, “Opportunity is missed by most people because it is dressed in overalls and looks like work”.
leftcoastjeff
 
Posts: 196
Joined: Thu Apr 17, 2008 6:35 pm
Location: Monterey, cal.

Postby leftcoastjeff » Sat Apr 26, 2008 4:30 pm

"coachgeo"

Believe that most tanks set up for Veg and diesel are vented to allow the return lines from the engine area to send air back along with fuel in the return. The air makes it's way out the vent as would the C02

Yes I understand.

But the CO2 could be an effective "blanket" to O2 influnces on the surface of the oil. It is pretty heavy as I can attest to personally. It's a long story, if your interested PM me and I'll try to explain.

Maybe CO2 pressure could be used for purging as well? "Quick Purge"
Hmmmmmm

LCjeff
'87F-250 stock, minus that pesky water seporator/air inlet, bone stock for now.

Thomas Edison says it best, “Opportunity is missed by most people because it is dressed in overalls and looks like work”.
leftcoastjeff
 
Posts: 196
Joined: Thu Apr 17, 2008 6:35 pm
Location: Monterey, cal.

Postby Welder » Fri May 30, 2008 4:46 am

IIRC, the idea of purging a veggie tank with inert gas was mentioned some time back on infopop. Nobody ever brought it up again that I know of.

When I went in to my local welding supply store for some lenses, I asked the guy about the price for argon. I referred to the smallest bottle he had as it would the most convenient in someones trunk. He named some crazy high price and after a few more questions it came clear that the pricew drops down nicely as the bottle (tank) size increases. Unfortunately, the best deals came with huge bottles.

I'd love to see a cost to benefit analyses for an argon purged veggie tank versus adding TBHQ.

Most people do nothing and don't have much trouble, but occassionally you hear about some horrendous soupy mess of vegpoly chocking up a guys tank.



BTW, I don't know if CO2 works effectively to prevent vegpoly formation, but I've heard that it isn't truly inert. Apparently when used in welding, it's considered an active gas. The term would be MAG, rather than MIG. I always thought it was fully inert. I guess if electricity can split H2O into hydrogen and oxygen, it might also split CO2 into carbon and oxygen. I remember seeing guys trying to pull (welding backhand, rather than forehand) an aluminum weld and getting black soot all around the edges of their weld zone, so maybe CO2 isn't inert after all. Since people wouldn't be running an arc in their veggie tanks, it should be fine as a veggie purge gas.

CO2 may work fine for purging tanks. I hope so. I think it's cheaper than argon...
"Is there anybody out there?"

Roger Waters
Welder
 
Posts: 189
Joined: Sat Mar 08, 2008 4:06 am
Location: B.C. Canada

Postby Burbarian » Fri May 30, 2008 11:58 am

CO2 is stable in standard temperature and pressure. However, in the presence of high reactivity metals like aluminum or magnesium, it becomes an oxidizer. This is because the bond affinity between aluminum and oxygen is much greater than that between carbon and oxygen, so the hot aluminum strips oxygen from the carbon dioxide. This produces carbon monoxide and soot. In fact, fine aluminum powder suspended in a pure CO2 atmosphere can be ignited with a strong electric spark. Same with a magnesium ribbon used as a conductive filament under the same conditions. Some metals are so reactive they'll strip oxygen from H2O, releasing hydrogen gas. Which is typically ignited by the heat of reaction. Lithium, sodium, potassium, rubidium, cesium, explosively react with water in this manner.

Argon is a noble gas, like neon and helium, and is inert.

Nitrogen gas is also relatively inert at standard temperature and pressure, and doesn't provide an oxygen source. It will however bond with oxygen at high temperature and produce nitrogen oxides.

Here's a stupid idea: Anybody ever toss a chunk of dry ice into a barrel of oil? If you then seal the lid and had an air check valve to allow air to vent out but not come back in, the cold heavy CO2 will preferentially displace any regular air and vent it out the barrel.
1987 GMC Suburban 6.2L V8 IDI
1985 Merc 300TD
1968 CAT D4D 3304 dozer
1971 Waldon 4100 loader
1981 IHI 30F excavator
1995 Changfa 195 w/ ST 10kw genset
Burbarian
 
Posts: 195
Joined: Wed Mar 05, 2008 12:14 pm
Location: Vermont

PreviousNext

Return to 2 Tank veggie oil conversion and General discussion

Who is online

Users browsing this forum: No registered users and 0 guests

cron