Why not Butanol?

It tastes horrible, and makes you go blind. Apart from that, it's alright.

It takes even more energy to distill.

Tim

-- Deep Friar: a very philosophical monk. Website:

More than the additional energy it will produce? Does that include the additional energy to truck ethanol around the country since it can't be shipped through the excisting pipeline? Mike

Oh it's not so bad...

Just imagine all those distillation columns at the refinery distilling crude oil fractions...

Michael

Doesn't it's solubility in water represent a signifigantly greater health and safety issue?

RL

=2E..

It has a much lower solubility than ethanol, and is close to that of gasoline itself.

Its health rating on MSDS shows it being less hazardous than reagent grade ethanol, and less hazardous than gasoline (with or without MTBE).

What hazard did you have in mind?

David A. Smith

When I was looking up on Ethonal I ran across it and I thought the same. But IIRC there was one sticking point for it that make it less viable than Ethanol.

Potential problems with the use of butanol fuel The potential problems with the use of butanol are similar to those of ethanol:[citation needed]

a.. To match the combustion characteristics of gasoline, the utilization of butanol fuel as a substitute for gasoline requires fuel-flow increases (though butanol has only slightly less energy than gasoline, so the fuel-flow increase required is only minimal, maybe 10%, compared to 40% for ethanol.) b.. Alcohol-based fuels are not compatible with some fuel system components. c.. Alcohol fuels may cause erroneous gas gauge readings in vehicles with capacitance fuel level gauging. d.. While ethanol and methanol have lower energy densities than butanol, their higher octane number allows for greater compression ratio and efficiency. Higher combustion engine efficiency allows for lesser greenhouse gas emissions per unit motive energy extracted. As an advantage, butanol production from biomass could be more efficient (i.e. unit engine motive power delivered per unit solar energy consumed) than ethanol or methanol routes. Also, some bacteria that produce butanol are able to digest cellulose, not just starch and sugars.[citation needed]

But the main issue is

Research challenges The key research challenge that must be resolved is that butanol production inhibits microbial growth even at low concentrations. The result is that the product of the fermentation is less than 2% butanol. The overwhelming majority of the fermentation broth is water, so an energy-intensive distillation step is required for purification. This may be acceptable if the goal is to produce butanol for use as a solvent, but if butanol is to gain traction as a motor fuel, energy inputs into the process need to be minimized.[15]

The Swiss company Butalco GmbH uses a special technology to modify yeasts in order to produce butanol instead of ethanol. Yeasts as production organisms for butanol have decisive advantages compared to bacteria.

I believe it is like almost 20% for ethanol.

I guess you haven't heard of wiki yet?

Do you mean the third link in my original post? Mike

You gotta read them for it to mean anything? ;)

Looks good, although I don't see anything to do with distillation.

Ah, good point. But how much power is spent doing that, and does it compare at all to 99% H2O? It sure takes a lot of energy to evaporate water.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

Ethanol is frequently distilled using something like an osmotic membrane:

I believe its much more efficient than the vaporization process. There was some news about a small home ethanol plant that fermented sugar and distilled the product for motor fuel use. It used the membrane method.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
Programmers don\'t die, they just GOSUB without RETURN.

Yes jon, I did read the wiki.

You say; " a.. To match the combustion characteristics of gasoline, the utilization of butanol fuel as a substitute for gasoline requires fuel-flow increases (though butanol has only slightly less energy than gasoline, so the fuel-flow increase required is only minimal, maybe 10%, compared to 40% for ethanol.)"

So it looks like Butanol has the advantage over ethanol.

You say; " b.. Alcohol-based fuels are not compatible with some fuel system components."

I see that Butanol is less corrosive than ethanol on most components. So again, it looks like Butanol has the advantage over ethanol.

You say; c. Alcohol fuels may cause erroneous gas gauge readings in vehicles with capacitance fuel level gauging.

This is troublesome, it is expensive to change gauges in existing vehicles. That said, I would think there is some gasoline/Butanol mix percentage that the fuel gauge will still work properly. It would be interesting to know that percentage. I'll call this a draw until we find out if that percentage mix is higher than 10%.

You say; "d. While ethanol and methanol have lower energy densities than butanol, their higher octane number allows for greater compression ratio and efficiency. Higher combustion engine efficiency allows for lesser greenhouse gas emissions per unit motive energy extracted. As an advantage, butanol production from biomass could be more efficient (i.e. unit engine motive power delivered per unit solar energy consumed) than ethanol or methanol routes. Also, some bacteria that produce butanol are able to digest cellulose, not just starch and sugars.[citation needed]"

Looks like you a least partially gave the advantage to Butanol on this one with the second paragraph. When you say "higher octane number allows for greater compression ratio and efficiency. Higher combustion engine efficiency allows for lesser greenhouse gas emissions per unit motive energy extracted." That may be true, but if the existing autos don't have the higher combustion ratio than it's meaningless. So, I'll call this one a draw.

2 for Butanol, 2 draws---advantage Butanol. If you would care to apply some critical thinking to the subject, I'd like to see it.

Now Jon, there is one part of the wiki that didn't stick in my memory.

"The Swiss company Butalco GmbH uses a special technology to modify yeasts in order to produce butanol instead of ethanol. Yeasts as production organisms for butanol have decisive advantages compared to bacteria"

The modified yeast method is interesting, thanks for bringing it to my attention.

Thanks, Mike

That's interesting. A similar process for the wine industry has become controversial in Europe. Using membrane filtration to extract water from low-grade grape juice or wine concentrates the flavor, but some wine fans seem to think this is cheating or somehow violates the wine-making tradition.