You Don’t Have to Be a Rocket Scientist … But it Helps
Posted: October 31, 2007
The vast majority of ethanol produced this year (94%) will be used as an oxygenate additive in blends up to E10 with gasoline, which brings considerable value to the gasoline fuel market.
This chart (which looks like something you studied in chemistry and would probably rather forget) shows that the energy density of ethanol is lower than gasoline and that the octane value (AKI) is much higher than gasoline. In practice, this means blends like E10 or E15 provide large oxygenate benefits that more than offset the slightly lower energy density.
The illustration on the right (which is much easier to understand for those of us who failed chemistry) compares corn ethanol to Methyl tertiary-butyl ether, more simply known as MTBE - which has been the anti-knock fuel additive of choice since 1979. That is, until a few years ago when environmental and toxicity concerns about the compound began to surface. The figure shows that corn ethanol has 88 percent more oxygen than MTBE and is a superior oxygenate combined with the environmental benefits gained from replacement of MTBE. In practice, such ethanol blends provide superior power for acceleration and the extra oxygen facilitates cleaner burning of the gasoline resulting in fewer tailpipe emissions.
Class dismissed.
kum dollison Said,
November 1, 2007 @ 12:26 pm
Which means, of course, that you can run a smaller displacement engine with higher compression ratio, and while achieving equal power come out with, virtually, the same “mileage” as a larger, lower compression engine running unleaded gasoline.
This, of course, is Really Important since, according to e85vehicles.com/, the spread between unleaded and e85 is steadily increasing.
kum dollison Said,
November 1, 2007 @ 12:57 pm
Oops, that should have been ” e85prices.com/ “