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Author: Subject: Valorizing the Glycerol from Biodiesel Production
not_important
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Acrolein is 3 carbons, glyoxal is 2; unless you meant oxidative cleavage. Ozone will cleave the double bond, if worked up under reducing conditions you'll get the aldehyde.

An alternative would be to oxidise one of the primary hydroxyl groups to the aldehyde, then cleave the remaining diol functionality with periodic acid.

I think that neither would be cost competative with the established routes to glyoxal.
Jome
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Caulerpa taxifolia is a "macro algae" and consists of 60 mass percent oil, according to references I can't seem to find at the moment. I did a small essay on it in college (eq.). It's mentioned in Wikipedia, but I acknowledge that's not a good source.

Caulerpa taxifolia apparently reproduces extremely fast and is only eaten by very few organisms. Aquarium bred strains with the capability of surviving in subtropic (instead of tropic) waters where there is no natural enemy has led to the name "killer algae", it simply outbreeds everything else.

I'm thinking of something like a floating factory-platform (in tropical waters) and hydrostats* floating in a radial pattern a few hundred meters out from it, with the algae growing on these, simply pulled in when it's time to harvest.

*Device that "stands still" at a certain depth in water.

Tacho
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Jome, are you saying that for every 100kg of dry algi we have 60kg of some triglyceride?

Could somebody confirm that? That would be THE most impressive thing I've heard lately.

Ozone
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Hello all,

Attached is a paper giving the fatty acid breakdown of C. taxifolia. Unfortunately, they do not give the simple mass balance. Their numbers are reported as % on total fatty acid, of this some 45.2-73.6% are unsaturates, principally C16 (hexadecanoic or palmitic acid).

Another page, though, gives the following:

"...1.3% on fresh weight caulerpenyne (the active toxicant in the algae) or greater than 2% on dry weight."

http://www.sbg.ac.at/ipk/avstudio/pierofun/ct/ct-4.htm

This seems to indicate a moisture content of only ~50%. I this is the case, I would expect low cellulose and lignin (algae is not designed to stand upright in a gale). So, on this, certainly no more than say, 50% lipid would likely be found. This would still be a highly significant, profligate source, though.

http://www.americanenergyindependence.com/biodiesel.html

I will attach the large NREL algae program report on the next post. It appears from this that, from certain strains, 50% or more (on biomass) of lipid can be obtained from algae...*amazing*.

Still, with all of that algae growing off-shore, we will sure be making one hell-of-a-lot of glycerol...

Happy Motoring,

O3

Attachment: C taxifolia_01.pdf (184kB)

-Anyone who never made a mistake never tried anything new.
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Ozone
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The NREL report for reading on the crapper!

O3

-Anyone who never made a mistake never tried anything new.
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Twospoons
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A more viable use might be as a fuel in fuel cells. Methanol, ethanol, and ethylene glycol can all be used in direct liquid fuel cells - so I'd imagine glycerol could be too.

Helicopter: "helico" -> spiral, "pter" -> with wings
chemrox
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What is a macro algae? I think of kelp which is easily harvested. The ease of harvest is due not only to its size but its habitat along the coast, almost inshore....

Where does C. taxifolia live?
chemrox
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Caulerpa taxifolia is a threat to the marine environment and is the subject of numerous eradication related articles (Google it). Perfect for biofuel projects!
Ozone
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Hello all,

I keep trying to upload that NREL file (it's about 3Mb), but to no avail!

Micro=single cells (blue-greeners and friends)
Macro=organism constructed of single cells (kelp)

Unfortunately, the kelp is very high on the "moisture % biomass" end, and requires a lot of energy in drying (latent heat is heat when calculating fuel value). I do not mean a small scale operation whereby the material is dried in the sun. I am referring to a 3.5E10 gal (a Curie of fuel, in gallons, WOW, or ~1.3E11 L) of renewable liquid fuel by 2015. The biomass must be amenable to immediate processing with minimal pretreatment!

Although this is practically impossible, the algae route makes it at least worthy of discussion over beers (with the occasional napkin).

Sauron started another thread that I think is relevant to this discussion (that is, interesting things to do with glycerin):

Where he pointed out the utility of HCl(g) which makes chlorination of the primary (1 and 3) positions feasible (in liquid phase the Sn1 predominates resulting in chlorination of the 2-position).

Still... I quote, "with all of that algae growing off-shore, we will sure be making one hell-of-a-lot of glycerol".

Cheers,

O3

-Anyone who never made a mistake never tried anything new.
--Albert Einstein
Sauron
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Triacetyl glycerin, or glycerol triacetate is a common industrial chemical called triacetin.

@O3, did you try my idea from another thread about oxidizing the center -OH of glycerol selectively with TCCA to form 1,3-acetonediol and then using TCT/DMF to chlorinate that to either chloroacetone or to sym-dichloroacetone?

Those are nasty unpleasant compounds (my specialty it seems) but of industrial significance (like acrolein).

Normally you'd use dry HCl to chlorinate glycerol to 1,3-dichloroglycerol then oxidize the remaining hydroxyl to carbonyl. Perfectly practicable and well trod, the new route just appears to be easier (avoids all that HCl generation). If it works of course.

[Edited on 11-2-2007 by Sauron]
Sauron
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If you use dry HCl on liquid glycerin you never chlorinate anything but the 1 and 3 position (or at least, very rarely).

And if you oxidize glycerin with TCCA you will selectively transform only the 2-position to carbonyl, never forming any aldehyde.

(The rates being so different that stopping when all the 2 -OH has been oxidized does not allow time for aldehyde formation at 1 or 3.)

Those are first step in two different schemes, not same scheme, althpough you could combine then and use TCCA to oxidize 1,3-dichloropropane rather than the classical method.

Remember, TCCA is one of those reagents (too few) that are effectively recyclable. The cyanuric acid precipitated, can be chlorinated back to trichloroisocyanuric acid.

TCT also produces cyanuric acid quantitatively if all three of its chlorines are hydrolyzed, but AFAIK it is not so easy to reverse that. I think oxalyl chloride works for that but it's too costly to be practical for this purpose, it's far cheaper to depend on the cheap industrial process to make TCT from HCN and HCl (it's the trimer of cyanogen chloride.)
Ozone
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Thanks Sauron, this is true!

Glycerol esters are viable products (as are the wacky ones I working on), but, my personal concern is...If we produce 35E9 gallons of, say, biodiesel (very simplistic, know, but I'm just making an example), well let's see...

With an average molecular weight of ~298 g/mol (ethyl stearate, glycerol is ~92 and stearic acid is ~284 g/m ol), assuming 3.5E10 gallons means 1.33E11L (which is approximately the same by weight as the density is very close to 1 g/cm3) some 1.7E12 moles of the ester or...5.7E11 moles of glycerol. This is amounts to about 5.7E7 tons (1 ton = 909kg or 2000lb).

By the gods that's a shitload,

O3

-Anyone who never made a mistake never tried anything new.
--Albert Einstein
Sauron
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@O3, I suspect biodiesel (like fuel ethanol) are at worst fads and at best small niches in the overall energy economy. Presently in fashion because they are allegedly "green" and "sustainable and mostly so the politicians can make the farmers and esp the agroindustry salivate over subsidies.

Back to TCT, which gives cyanuric acid as a waste product, while it can't be so easily cycled back into TCT it can be easily chlorinated back to TCCA and this is a definite plus in its favor.
Ozone
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There is no doubt of that! It is a stop-gap at best. At the current goal level, we would be seeing ~11E9 gallons of fuel, this equates to roughly 1/4 of viable agrispace in the country. Cranking this up to 35E9 required roughly 3 times more agrispace, at the behest of food.

Mexico is operating as the canary in the mine (no offense) since the economy there is fragile (and corn is a primary foodstuff) enough to feel this fuel vs food dichotomy. A tiny shift in the trade value on commodity corn = more expensive tortillas.

This will happen here as well if more sensible alternatives are not persued. We need to look into cellulosic ethanol made from agriwaste and split stream that to say, make ethyl-algae-biodiesel. The current methods will be with us for a while though since industrial inertia is difficult to surmount.

Any process with the potential to back process is good. It seems to me that the cyanuric acid itself could be a product as well. How about going from cyanuric acid to atrazine? The oxidations required should be feasible electrochemically (now to make it cheaper than condensing HCN/cyanic acid).

Cheers,

O3

-Anyone who never made a mistake never tried anything new.
--Albert Einstein
not_important
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I think that simply switching back to using glycerol in existing applications can soak up a lot of the production. Industry moved away from it as petrochemicals became more widely produced.

Glycerol can be used as a sweetener, one that doesn't promote plaque forming bacteria. It can replace propylene glycol, which displaced glycerol, in many food and medical applications.

Fermentation processes can be used to convert glycerol to 1,3 propylene diol. It can be used in deicing fluids, where it replaces the toxic ethylene glycol. Other fermentations produce chiefly propionic acid with smaller amounts of succinic and acetic acids; different bacteria will chiefy produce succinic acid, or formic acid and ethanol.
Ozone
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Indeed. Good call, not_important!

Here is a nice biodeisel blog:
http://www.trianglebiofuels.com/blog/index.php?paged=2

From here is quoted:

Columbia, Missouri - In addition to topping off your gas tank with biodiesel, a new advance could let you fill your vehicle’s cooling system with a biomass-derived antifreeze. A new process developed at the University of Missouri-Columbia (MU) creates a valuable secondary product from the biodiesel manufacturing process that makes the production cycle both profitable and affordable.

Galen Suppes, chief science officer of the MU-based Renewable Alternatives, developed a process for converting glycerin, a byproduct of the biodiesel production process, into propylene glycol, which can be used as nontoxic antifreeze for automobiles. Suppes said the new propylene glycol product will meet every performance standard, is made from domestic soybeans and is nontoxic.

Suppes said this technology can reduce the cost of biodiesel production by as much as \$0.40 per gallon of biodiesel. The market for propylene glycol already is established, with a billion pounds produced a year.

“The price of propylene glycol is quite high while glycerin’s price is low, so based on the low cost of feed stock and high value of propylene glycol, the process appears to be most profitable,” Suppes said. “The consumers want antifreeze that is both renewable and made from biomass rather than petroleum from which propylene glycol currently is produced.”

The creation of a valuable secondary product could help mainstream the use of biodiesel. In 2004, biodiesel producers sold 30 million gallons of fuel, up from 500,000 gallons in 1999. It’s still, however, a relatively niche fuel.

“At best, right now biodiesel production is only part of the solution,” Suppes said. “Current biodiesel production in the United States is about 0.03 billion gallons per year as compared to distillate fuel oil consumption of 57 billion gallons per year.”

Renewable Alternatives is currently licensing this technology to three biodiesel plants. The National Science Foundation and Missouri Soybean Farmers are helping to fund the research.

Definitely an option!

O3

[Edited on 11-2-2007 by Ozone]

-Anyone who never made a mistake never tried anything new.
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Welder
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Glycerol fermentation.

Hello everyone.

I'm only a humble tradesman (welder), not a scientist, but I joined this forum hoping that more chemically competant folks could help advise me on chemistry issues. I'm predominantly interested in biofuels issues, but may need help in other chemical specialties as well.

Anyway, I read most of this thread and although I understood a lot of it, there were also many areas where I just couldn't follow strongly along. I understand that the thread started out trying to find profitable, viable ways to use biodiesel brewing byproduct (glycerol), but near the end it was pointed out that there may be existing uses that have been abandoned in favour of other more viable chemical substitutes. For example, it was mentioned that glycerol can be used as a sweetener or after conversion to propylene glycol it may be used in place of the more toxic ethylene glycol.

My question is regarding the potential of using glycerol as feedstock in ethanol fermentation.

Can glycerol be profitably fermented to produce cheap ethanol? By cheap, I don't mean cheaper than cellulosic ethanol, but cheaper than grain ethanol.

If glycerol can be used to ferment and distill anhydrous ethanol, it may be a practical co-solvent along with methanol in transesterification. It could be produced on-site wherever larger commercial biodiesel breweries can afford to run an ethanol brewery/distillery and combine their own ethanol with purchased methanol.

If what I propose is technically viable, it is likely more practical than a biodiesel brewery using their glycerol to feed their own in-house methane digesters and then using the methane as process heat, or converting it into methanol as process solvent.

Any input?
not_important
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There's been a lot of effort put into finding useful and practical fermentations of glycerol; a few have been developed in the last couple of years.

There's other uses for some of the glycerol in regards to biodiesel. Convert some ethanol to acetaldehyde and react that with glycerol to for the cyclic acetals, which are useful as oxygenates in the biodiesel.

Remember that there is very roughly 16 times as much carbon in the fatty acids part of oils as in the glycerol part. This means that while increasing the utility of the glycerol, it's not going to be a big boost in fuel production.

One problem with fermenting the glycerol wastes from based catalysed do-it-in-the-basement biofuels is that the salt content inhibited fermentation. Going to acid catalysed transesterfication using reactive distillation eliminates the salt problem. It also allows the use of feedstocks with considerable amounts of free fatty acids, meaning waste/used oils and fats can be used. For the US the amount of waste oils from industrial and commercial users would allow the production of biodiesel amounting to 5 to 10 percent of the current fuel consumption of the US.

Two references, the first is

doi:10.1016/j.copbio.2007.05.002
Current Opinion in Biotechnology
Volume 18, Issue 3, June 2007, Pages 213-219

Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry

Syed Shams Yazdania and Ramon Gonzaleza

and the second is the attached PDF

Attachment: Hydrogen and Ethanol Production from Glycerol Wastes.pdf (354kB)

Welder
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Thank you very_important. I really appreciate your informative reply. It's nice having some friendly and chemically competant guidance.

I'll pass the info you gave along to the other biofuels people I know. If glycerol based ethanol production is an economically viable way of disposing of biodiesel produced glycerol, then perhaps some small commercial biodieselers I know may test it in their operations.

I don't really want to take this thread off topic, but I have two other biofuels related questions:

Although I think biodiesel is a great fuel and fuel additive, lately I've been looking into a biofuel option called SVO. The acronym SVO stands for straight vegetable oil. Basically, instead of transesterfication, vegetable oils are heat thinned until the viscosity approaches that of diesel oil. This is typically accomplished on board through the use of heat exchangers tapping waste engine coolat heat as well as supplementary electric heating.

Anyway, most svo users are actually burning WVO (waste vegetable oil) recieved from restaurants. This supplies the svo/wvo users with cheap fuel, but the quality of wvo varies widely and significant refinement is required to come up with a usable fuel.

Aside from filtering out food particles and washing away salts, sugars and water based acids, the WVO users are also faced with free fatty acids, as you already mentioned earlier regarding used oils.

Although FFAs are an issue for home biodiesel brewers using WVO as feedstock, most svo users simply ignore the FFAs and just burn the WVO along with the FFAs already present.

My first question relates to the potential of fuel system corrosion in WVO fuelled vehicles. Some WVO users think FFAs are acidic enough to corrode the steel injection pumps and injectors while others feel that FFAs aren't acidic enough to do any damage, even over long-tern exposure. If WVO has been filtered down to 1 micron and has also been water washed to remove salts, sugars and water based acids, then dewatered to less than 700 PPM, is there still a significant risk of corrosive action from the FFAs being in long term contact with steel fuel system components? Simply restated, are FFAs corrosive to steel?

Those who feel that FFAs pose no corrosive threat to injection systems believe that reports of corrosion are more likely related to inadequate dewatering and/or failure to water wash the salts and water based acids from WVO. As salts, sugars and water based acids are hygroscopic, miost air drawn into a fuel tank as the fuel level drops could easilly condense on fel tank walls and dribble down into the WVO making salt residue and previously dehydrated water based acids more corrosive.

If FFAs are not corrosive to regular steel, then they can likely be left in WVO and burned as fuel.

My second question is regarding polymerization. Again, due to economics, WVO is the material in question. As I understand it, polymerization of WVO starts in the fryer due to heat and exposure to oxygen and possibly metal ions acting catalytically. I've heard that unless the oil is damaged by oxygen, it won't likely polymerize. There are a number of potentially suitable antioxidants to use as vegetable fuel stabilizers so I won't ask you to recommend any, but lately I've heard of fairly extreme examples of polymerization occurring in WVO bearing high levels of FFAs. I assume the FFAs are elevated due to greater use before being discarded into the waste oil bin, but I'm not sure if there are any other causes of FFA formation, or if higher FFA levels mean a greater likelyhood of WVO polymerization. I also am unaware of whether or not antioxidants can help prevent FFAs from polymerizing, or even whether or not FFAs even polymerize at all.

Do you think antioxidants or any other potential fuel additive may likely help prevent FFAs from polymerizing?

not_important
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Not an area that I've experience in, but I've read on it.

The FFA problem seems to be real. The mention here http://journeytoforever.org/biodiesel_svo.html#gnl matches what I've heard elsewhere - pump corrosion can be a problem. Water is likely an important factor, really drying the oil will take some work. Di- and mono-glycerides in the oil may draw in some water too, undoing the drying. And even dry fatty acids are still acid and can attack metals.

Polymerisation is quicker when hot, but proceeds at any normal temperature. It's the same as the drying oils used to make oil-based paint, those are more unsaturated than food oils but the process is the same. And as the unsaturation is in the fatty acid part of the oil, the free acids will polymerise as well. Water wash, chelating agents to inactivate traces of metal ions, and anti-oxidants all help.

A third issue that you mention is the viscosity, vegetable oils at 80 C still have a much higher viscosity than diesel. The temperature needed varies from source to source, I've seen numbers ranging from 110 to 150 C to reach compatible viscosities.

My personal opinion is that going the transesterfication route to biodiesel, using the glycerol to build oxygenates and thinners for the simple biodiesel esters, and perhaps convert some to mono-alcohols, is the best bet. Using reactive distillation ordinary rendering methods can be used to strip the feedstocks of salts and other water solubles, there's no need to dry the oils, and you cam mix the oil with the esterfication alcohols to make the filtering stages easier.
Welder
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Drying WVO has been a challenge, but a WVO user named Sunwizard has proven that by using cheap automotive centrifuges (CF), adequate dewatering is possible. Of course settling and decanting preceed the CFing of the WVO, but the CF has proven to do the job acceptably.

Of particulat interest to me is your mention that FFAs are the unsaturated part of the oil. Does this mean that FFAs can be saturated chemically, such as through hydrogenation? If so, then I would wonder if hydrogenated fatty acids would still be able to corrode steel or not?

Wouldn't saturation via hydrogenation make a more stable and less corrosive molecule? Don't worry, I know trans fats are not healthy to eat, but as completely combusted fuel they should be safe...and carbon neutral!

I understood your advice steering me toward transesterification, but with methanol being a dangerous and expensive factor in biodiesel production, I'd rather perfect running diesel engines on free WVO. Methanol isn't free, but WVO usually is

[Edited on 15-1-2008 by Welder]

[Edited on 15-1-2008 by Welder]
not_important
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Saturation brings higher melting points and increased viscosity problems - you end up with shortening instead of oil. Won't affect their ability to work as acids.

It's the fatty acids, free or esterified with glycerol or methanol, that are unsaturated. Both the free and esterified acids can polymerise. Used oil also likely has had some acrolein formed, and that easily polymerises to gorp as well as forming lighter weight water extractable acids. The free acids are likely to increase corrosion, bringing fresh metal ions into the oil, making polymerisation more likely.

How bad the corrosion problem with dried WVO is will take field experience to learn, the sample size is rather small right now and the sample population has a lot of boosters who tend to overlook problems they may meet. Water certainly makes things worse, I believe the real question will be in regards to how much water tends to accumulate in the processed oil.

WVO may be free or very low in cost, but the processing and modifications to the vehicle add to that. Replacing stressed or corroded parts adds even more cost. I must also comment that "...4 passes seems to get most of the particles out, so it takes 2-3 hours for a 40-50 gallon batch." That's filtering hot oil, which also means additional costs in the heating and pumping, and spending time doing the work - time that isn't included in the costs.

This reminds me so much of the late 60s through mid 70s, with people building housing out of metal sheet from abandoned automobiles, cut open and flatted drink cans, and so on. The problems with leaky roofs in the rainy season tended to to be discussed nearly as much as the joys of those alternative sources of building supplies. There's alway been the tinkerers, often putting more effort into their alternative methods than they'd expend to buy the mainstream item, just as there's been hobos and the like, avoiding settling down into a conventional life. Fine and good, but hardly a solution for society at large.

And not a low cost solution likely to last, as cheap WVO will become something of value. A friend was describing a grocery store that fueled their backup generator with diesel to get the engine up to heat, and WVO after that. They buy the WVO from someone who has sewn up most of the larger producers of WVO in the area, partially by switching to paying a small amount for the oil rather than just hauling it off. Cleans the oil up in a plant built for the task. That guy is in competition with the biodiesel people for VO supplies, as petroleum prices go up they may be getting in bidding wars for the WVO. And leaves the amateur SVO crowd hunting for their stocks from the smaller producers of WVO, the ones where it's not worth the big players time to collect a couple of gallons of WVO a week from.
Welder
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The higher melting poiints and increased viscosity aren't a problem as many folks have found success running on lard, tallow, and palm oil. The key is to start the engine on either biodiesel or petrodiesel and tap into the waste engine heat to liquify the solid fuel.

I thought that saturating the WVO through the use of an indusrial enzymatic hydrogentor (available by lease) would help prevent polymerization. Saturated oils don't easilly polymerise, do they?

The conversion costs of preparing a diesel vehicle to SVO/WVO operation are a one-time cost, while methanol is a substantial recurring cost to biodiesel brewers. A local engineer I know brews biodiesel for about 35-46 cents/gallon. The costs to adequately dewater esters or WVO are the same. Esters may dewater more easilly due to the reduced viscosity, but since heat is required in both instances, the difference is unimportant. A kilowatt hour of heating and centrifuge pumping costs the same regardless of fluid processed.

Yes, biodiesel is easier than WVO/SVO, but petrodiesel is easier still. Out of the three, SVO/WVO is cheapest by far, providing that corrosion and other obstacles don't bring repair costs onto the ledger. That's why I'm asking these questions, I'm trying to bring SVO/WVO into a point of full maturity in the same way that biodiesel people worked over their problems in the early days of biodiesel.

While there are never WVO refinery explosions, there have been a substantial number of biodiesel breweries that have suffered fires and/or explosions. Safety and economy favour SVO/WVO.

Yes, the bidding wars will inevitably come. Staying ahead of the pack is the key to sustainability there.
microcosmicus
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To follow up points being raised above and see how important vegetable
oil might be in the grand scheme of things, I had a look at some data.
While these may not be the best numbers, they should at least be good
enough for back-of-the envelope estimation.

The total world production of vegetable oil is 5.5E10 kg per annum
(http://findarticles.com/p/articles/mi_m3819/is_1991_July/ai_...)

The total world production of petroleum is something like 2.3E10 barrels
per annum (http://www.eia.doe.gov/emeu/cabs/topworldtables1_2.htm)

Each barrel yields 74L of gasoline.

Given that gasoline has a density of 0.68 g/cc, that all amounts to
something like 1.1E12 kg gasoline per annum.

So it seems that, whilst vegetable oil alone cannot do as
an alternative fuel, there is at least a large niche market.

 Quote: WVO may be free or very low in cost, but the processing and modifications to the vehicle add to that. Replacing stressed or corroded parts adds even more cost. I must also comment that "...4 passes seems to get most of the particles out, so it takes 2-3 hours for a 40-50 gallon batch." That's filtering hot oil, which also means additional costs in the heating and pumping, and spending time doing the work - time that isn't included in the costs.

Of course, the energy needed to heat the oil so as to filter it can come
from burning the oil, so that can be calculated into the yield.

Should this yield be unacceptably low, there are applications
less demanding than internal combustion engines where minimally
purified oil will do just fine. For instance, look at the waste oil
burner which Lionel Oliver uses to melt metal:

http://www.backyardmetalcasting.com/oilburners01.html
http://www.backyardmetalcasting.com/oilburners02.html

I could imagine a similarly designed burner used for home heating or
for boiling steam to run a turbine and generate power.

Sure, the fatty acids are going to be as corrosive, but the costs are going
to be smaller if one is dealing with a simple burner than an engine. Because
the parts need not be as precise, they will cost less and can take more
abuse from corrosion before needing replacement.
Welder
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Hi Microcosmicus.

I agree that the obstacles to using WVO as heater fuel are less than those pertaining to auto fuel, but although I certainly plant to build a WVO boiler/furnace eventually, for now, I want to reduce my auto fuel costs.

As mentioned earlier, there are industrial enzymatic hydrogenators available for lease, but I can't seem to find the source. I know I read the article somewhere, I'll just have to keep searching. I'm assuming of course, that hydrogenating filtered/dewatered WVO will reduce the polymerization activity of the WVO cheaper or more effectively than an antioxidant would.

Is there any way to de-acidify the FFAs without having to make them into soaps? If not, would such FFA soaps make safe, envirinmentally friendly fuel? I hear of biodiesel brewers converting their FFAs to biodiesel through a process called an acid-base reaction (at least I think that's the term). Biodiesel is great, but I'm just trying to avoid requiring methanol in the production of a cheap, reliable and sustainable biofuel.

Even if FFA soaps are highly hygroscopic, that's no problem as long as they are still flammable liquids when fully dried. ASVO/WVO users are comfortable with extensive modifications so dessicant breather on the fuel tank can prevent water contamination affordably.

Any other ideas?
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