Sciencemadness Discussion Board

Bio-Ethanol for Gas Engens. Has anyone doen this?

SsgtHAZMAT - 29-11-2007 at 23:43

I read the thread on Diesel but did not see anything for a gas engine. As the price starts to climb I would be interested in building a still (A legal one!) to produce my own ethanol to top off the tank. As I read the data, I "should" be able to do this up to about 10% ethanol.

I was wondering if anyone here had done it yet?

not_important - 30-11-2007 at 00:02

In Brazil it is economical because of the large amounts of sugar cane grown, there are other similar regions. Depending on tariffs on sugar and high-starch products, it may be economical in other countries.

It is not a winning proposition in the US. even with the price of petrol as it is. The subsidies given the bio-ethanol manufactures are what make it economical there. The sugar tariffs imposed by the US make sugar too expensive as a feedstock, you either need very cheap molasses or start with starch and break it down into sugar.

Contrary to some the ethanol produced contains more energy than was expended in growing the feedcrop and the processing, this may not be true on a small scale.

Tacho - 30-11-2007 at 02:53

@SsgtHAZMAT: I think it all comes down to what you have available to ferment. The techniques and results vary wildly depending on what you have at hand to feed your fungus.
Quote:
Originally posted by not_important

It is not a winning proposition in the US. even with the price of petrol as it is. The subsidies given the bio-ethanol manufactures are what make it economical there.


@Not important: If you mean susidies to US manufactures, you are right. If you mean subsidies to Brazilian manufactures, I must disagree with you. Ethanol is an industry well stablished and paying good taxes here. Brazil has awesome natural advantages for producing ethanol. Actually, for all biofuels, but specially for ethanol due to a lucky combination of proper soil and weather.

I went to a simposium on biofuels some months ago, and one of the lectures was a comparative study of ethanol production in Brasil and elsewhere. The numbers were very, very impressive.

One of the figures I remember is the number of carbons in the biofuel over the number of fossil carbons released to make it. In US's ethanol is close to 1, some studies saying it may be lower than one. In Brasil's ethanol the average number is 9.

By the way, sugar cane does not produce well in the rainforest so, contrary to some press hype, it offers no threat to that.

evil_lurker - 30-11-2007 at 04:22

Practically speaking, one would do better to make some good hooch and bootleg it and use the proceeds to buy gasoline than to muck about with hundreds of gallons of wash needed just to make a tank of gas. :D

not_important - 30-11-2007 at 08:32

Indeed I was referring only to the US in regards to subsidies, one result of which is to push up the price of food corn.

12AX7 - 30-11-2007 at 10:30

Corn isn't used for human consumption in the U.S.

(The sweet corn which makes it to the dinner table constitutes 1% of the corn market.)

Tim

Ozone - 30-11-2007 at 17:01

Indeed, Brazil is doing an excellent job. Nearly every mill (sugar) I visited last Sept. was making very fine anhydrous fuel grade (nevermind the regional cachaca;)) ethanol (and also overy fine Cristal EU #2 sugar). They have an excellent plan in place and this was made to work by creating a ceiling price for gasoline (and etoh subsidy). This program works well in Brazil, where even a small mill is crushing 25,000 tons of cane per day. There a mills everywhere, and a good friend of mine is involved with the slated construction of over 70 more in the next few years.

A large mill in the US is crushing maybe 14,000. There are now ~ (not all mills are making sugar) 12 mills in Louisiana (the largest US cane sugar producer). The math there is obvious. On commodity basis, we cannot compete (with sugar and EtOH--we don't grow enough cane). So... To be competetive, we must work out the areas surround the production of cellulosic ethanol.

The cane mill is excellent for this for two main reasons:

1. The mill operates on bagasse, which is burned to make steam. The process is self contained. The remaining bagasse (roughly 2/3) can be used to make ethanol.

2. Besides being more energy efficient, and thus environmentally sound, ethanol produced this way does not compete with the food supply (which corn *does*, because it is used for animal feed).

By the way, just this level of ethanol production has driven corn from a 20 yr average of ~$1.67/bushel to almost $5 and soya beans from ~$5.00/bushel to over $9 in just one year.

Anything with fiber in it (and not too much lignin, which denatures your enzymes and can crap out your yeast) could be used. camel dung?

Pre-treatment can be a problem, though...

Cheers,

O3



[Edited on 30-11-2007 by Ozone]

not_important - 30-11-2007 at 18:17

Quote:
Originally posted by 12AX7
Corn isn't used for human consumption in the U.S.

(The sweet corn which makes it to the dinner table constitutes 1% of the corn market.)

Tim


http://www.iowacorn.org/cornuse/cornuse_3.html

2005-2006 U.S. Corn Use By Segment
(bushels)
Feed/Residual 6.1 billion (54.5%)
Exports 2.1 billion (18.8%)
Ethanol (fuel) 1.6 billion (14.3%)
High Fructose Corn Syrup 530 million (4.7%)
Corn Starch 275 million (2.5%)
Corn Sweeteners 225 million (2.0%)
Cereal/Other 190 million (1.7%)
Beverage Alcohol 135 million (1.2%)

Corn sweeteners are the older type of corn syrup - basically dextrose /glucose. Corn starch is used both in foods and as adhesive, stiffener, and other industrial applications. Corn as feed goes to producing food animals, meaning higher corn prices drive up the cost of meat. Much of the corn the US exports is used as food.

nitroglycol - 30-11-2007 at 18:42

I find n-butanol more promising than ethanol. Most gas engines won't run well on ethanol without modification; on butanol, many of them run just fine. There are bacteria, such as Clostridium acetobutylicum, which can produce butanol from biomass.

Of course, even with this, we'll likely have to drive a lot less in the future to avoid real trouble- at least until they have solar power satellites up and running. Then we should have plenty of electricity to charge up our electric cars.

Ozone - 30-11-2007 at 21:05

Thanks, not_important! Somehow, in my "general exam surreality" I forgot about perhaps the largest app of all. Oof.

nitroglycol (butanol is OK, but, the BP is actually rather high), check out TAMU's mix-alco process. In general, we avoid bacterial fermentation for two reasons:

1. Thin cell wall = crappy alcohol tolerance = fermentation under vacuum = loss of efficiency on the final energy balance.

2. OK, one since the sp. is not pathogenic.

Of interest might be the Gonzales (IIRC) group at Rice (which is correct) that is producing ethanol from glycerol using a special strain of E. Coli (unfortunately, for the above reason, the yields are something like 0.2% relative to the 5% which is nominal with S. cerevisea).

This is apparently also feasible with a Klebsiella (see 2, above, even though this is supposed to be an "environmental" strain) isolated from red deer. Similar yields. (I will post the papers, if anyone appears to be interested)


g'night,

O3

[Edited on 18-12-2007 by Ozone]

not_important - 30-11-2007 at 21:24

You're correct, Ozone. Butanol would need to be blended to get useful volatility. On the other hand, a blend with say 10 to 20 percent low boiling hydrocarbons would greatly cut back on petroleum consumption and perhaps could be provided by other biomass feed routes.

I think that gene tinkered bacteria will be needed to make butanol fermentation practical.

Fleaker - 17-12-2007 at 20:48

Yes, that 10 to 20 percent blend of low boiling point carbons (which have pitiful octane rating--not good for internal combustion) would work well with butanol. More volatility, slightly more energy density.


Seems to me that there needs to be some serious bio-engineering in the butanol arena.

@Ozone, I'd be interested in the refs. for those papers, or full papers if you have them.


There are yeast strains that tolerate up to 20% by weight alcohol solutions (Turbo Yeast).

Sauron - 18-12-2007 at 02:24

During WWII many nations turned to ethanol - not gasahol but straight ethanol usually 70-95% ethanol, balance water - for motor fuel.

This was "rediscovered" during the oil shocks in the late 60s.

But the auto industry queered the whole thing by changing the engine design in early 70s and it is now a bitch to retro-engineer contemporary engines to run on high proof ethanol fuel.

Hence all theb attn to "gasahol" despite its marginal economics, and requirement of anhydrous ethanol. Straight ethanol engines tolerated water just fine, so dehydrating the ethanol was never required. Up to 20-30% water in ethanol was no problem and the only adjustments required to those simpler old engines (pre early 70s) was a little carb adjustment.

HOWEVER, in my opinion "bioethanol" is not a solution. The solution is the demise of personal transportation as we know it.

We certainly cannot convery agriculture in significant measure to fuel production without putting the food supply at risk.

Presently, politicians use this and similar carrots to entice the farmers. But it is a boondoggle.

12AX7 - 18-12-2007 at 08:21

Public transportation works wonderfully in dense cities (Sauron, where you are, I bet the trains have people stuffing in passengers*), but fails miserably in diffuse suburbs. And there's a lot of suburban towns in the US and abroad.

*Or if you're not in a big city, then in the next big city over. Come to think of it, I don't think you have ever mentioned what kind of city you're in.

Tim

Sauron - 18-12-2007 at 09:55

A city of 12 millions with too many cars and too little public transport too late.

The paradigm shift I am talking about will require major changes in how cities are organized, patterns of workplaces vs residence and so on.

It will take time but there is little alternative, unless matter transmission becomes practical.

Ozone - 18-12-2007 at 16:29

Good evening all,

Here are those references (sorry, I got the Gonzales group confused with Simonetti. oops.) that you wanted!

OK, rather here's paper #1:

Attachment: E. Coli Dharmadi 2006.pdf (222kB)
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Ozone - 18-12-2007 at 16:34

And here's #2. I've recently done a mess of "literature survey" regarding cellulosic ethanol, biodiesel, and "what to do with all of that glycerol".

We are currently testing some ATCC "turbo yeast". I suspect that the high yields are occuring at very high attenuation (that is, very slowly). I think that a beer level of 10-12% (rather than the 5 or so we usually see) would be a step forward whilst keeping the "yeasty beasts" happy.

I'll keep an eye on this to see if I have any further relevant titles!

Cheers,

O3



[Edited on 18-12-2007 by Ozone]

Attachment: Red Deer Jarvis 1997.pdf (866kB)
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Intergalactic_Captain - 18-12-2007 at 18:47

10-12%'s a little low... Check out www.homedistiller.org - Their main focus is on beverage ethanol, but check out what people are doing there with vodka. You're on the right track with the "turbo yeast," but look into the fuel-grade versions...18-20% in under a week. A technique of feeding sugar over time is used to push 20%, but 16-18% should be straight-forward enough.

The turbo yeasts are basically just overfed distiller's yeast. Imagine you have a 20L wash - Instead of putting in a 1/4oz of normal yeast, you add 1/2lb of 50/50 yeast/nutrient. The only major issue is that a good bit of methanol and fusel oils are produced - Bad for drinking, but practilly irrevelevant for fuel.