AZBrandon
05-23-2006, 08:37 PM
http://www.butanol.com/
About a week ago I read my first article about butanol. It had a link to the above listed website which is admittedly corny and hits me as being very unprofessional appearing and would lean one to believe that butanol is perhaps yet another alternative fuel with no future.
I started doing a little more research however and the bottom line is that butanol is just another of the four major fuel alcohols comprised of methanol, ethanol, propanol, and butanol. Of the four, butanol is the least volitile, least corrosive, and has the highest octane and highest calorific content per gallon. It's also the only one that can be run in a gasoline engine unmodified unlike ethanol which needs to be mixed in with gasoline and can't be run in concentrations above 10% without special flex fuel tuning.
By the numbers, butanol looks incredible. Other than the cost (currently listed as running around $3.70/gal in bulk) it appears to be an ideal replacement for gasoline. Although the above mentioned website quotes calorific content at 64k, 84k, and 110k for the three primary fuel alcohols, other sources that I personally think are more reliable peg it at 57,000, 76,000, and 105,000 BTU per gallon for methanol, ethanol, and butanol respectively. This lets butanol compare very well against the approximate 110,000 BTU of E10 gasoline.
Now the biggest kicker is that everyone knows ethanol has a very high octane count. It has a RON of about 111 and MON of 92 for (R+M)/2 AKI "octane" of 101.5. Now since E85 is mixed with low grade gasoline, E85 falls in around 99 on the AKI scale, typically just rounded up and declared as 100 octane. Butanol however needs no mixing with gasoline, thus its values of 113 and 94 give it an AKI octane of 103.5.
Now most all modern engines, even the ones "tuned" for 92 octane fuel still have to be able to pull back timing and run on lower grades in case a thoughtless owner pumps in some 87 octane on accident. Also, 87 being the cheapest, its the fuel of choice for those trying to get the most distance per dollar of gasoline. You can only run up to around 9.5 to 10.5:1 compression on a standard gasoline engine designed for 87 octane and likely not much more than 11:1 even with direct injection.
Now if we start getting automakers to build engines exclusively for butanol, if we can throw away the notion of using gasoline on accident, then you could build an engine made specifically for it's extremely high octane and thus a compression ratio of 14 to 15:1 becomes possible. Increasing the static compression ratio by 50% will more than offset the fact the fuel has about 5% lower BTU count.
So other than the fact it appears ethanol is running $1.60/gal and butanol is $3.70/gal, why is it that butanol is all but entirely absent from the news? One would think that its ability to run in gasoline engines unmodified would be a huge selling point, especially since 91 octane fuel is currently around $3.50/gal in California anyway, so stepping up to 104 octane for another couple dimes seems like a no-brainer.
About a week ago I read my first article about butanol. It had a link to the above listed website which is admittedly corny and hits me as being very unprofessional appearing and would lean one to believe that butanol is perhaps yet another alternative fuel with no future.
I started doing a little more research however and the bottom line is that butanol is just another of the four major fuel alcohols comprised of methanol, ethanol, propanol, and butanol. Of the four, butanol is the least volitile, least corrosive, and has the highest octane and highest calorific content per gallon. It's also the only one that can be run in a gasoline engine unmodified unlike ethanol which needs to be mixed in with gasoline and can't be run in concentrations above 10% without special flex fuel tuning.
By the numbers, butanol looks incredible. Other than the cost (currently listed as running around $3.70/gal in bulk) it appears to be an ideal replacement for gasoline. Although the above mentioned website quotes calorific content at 64k, 84k, and 110k for the three primary fuel alcohols, other sources that I personally think are more reliable peg it at 57,000, 76,000, and 105,000 BTU per gallon for methanol, ethanol, and butanol respectively. This lets butanol compare very well against the approximate 110,000 BTU of E10 gasoline.
Now the biggest kicker is that everyone knows ethanol has a very high octane count. It has a RON of about 111 and MON of 92 for (R+M)/2 AKI "octane" of 101.5. Now since E85 is mixed with low grade gasoline, E85 falls in around 99 on the AKI scale, typically just rounded up and declared as 100 octane. Butanol however needs no mixing with gasoline, thus its values of 113 and 94 give it an AKI octane of 103.5.
Now most all modern engines, even the ones "tuned" for 92 octane fuel still have to be able to pull back timing and run on lower grades in case a thoughtless owner pumps in some 87 octane on accident. Also, 87 being the cheapest, its the fuel of choice for those trying to get the most distance per dollar of gasoline. You can only run up to around 9.5 to 10.5:1 compression on a standard gasoline engine designed for 87 octane and likely not much more than 11:1 even with direct injection.
Now if we start getting automakers to build engines exclusively for butanol, if we can throw away the notion of using gasoline on accident, then you could build an engine made specifically for it's extremely high octane and thus a compression ratio of 14 to 15:1 becomes possible. Increasing the static compression ratio by 50% will more than offset the fact the fuel has about 5% lower BTU count.
So other than the fact it appears ethanol is running $1.60/gal and butanol is $3.70/gal, why is it that butanol is all but entirely absent from the news? One would think that its ability to run in gasoline engines unmodified would be a huge selling point, especially since 91 octane fuel is currently around $3.50/gal in California anyway, so stepping up to 104 octane for another couple dimes seems like a no-brainer.