From the article:
"Coskata uses existing gasification technology to convert almost any organic material into synthesis gas, which is a mix of carbon monoxide and hydrogen. Rather than fermenting that gas or using thermo-chemical catalysts to produce ethanol, Coskata pumps it into a reactor containing bacteria that consume the gas and excrete ethanol. Richard Tobey, Coskata's vice president of engineering, says the process yields 99.7 percent pure ethanol."
The ideal chemical reaction would be:
(2)CO (Carbon Monoxide) + (4)H2 (Hydrogen) = C2H5OH (ethanol) + H20 (water)
and this would only occur if the feed materials were in the proper ratios — highly unlikely.
As noted above, the main by-product is water. And there most certainly be other byproducts, as in most chemical reactions.
And the process to separate the ethanol from water is usually distillation. However, ethanol and water form a 95% mixture which has a boiling point below either of the constituents, making it very difficult to obtan "99.7%" pure ethanol. They must use some other trick to achieve that purity.
Another thing is that this is currently a batch process. Some neat chemical engineering will need to be done to make this a continuous process, like that used in gasoline refineries to create the volume necessary.
And you still have the transportation problems to get the gasoline and ethanol to a common mixing facility to make the E85.
Also:
"Coskata won't have a pilot plant running until this time next year, and it will produce just 40,000 gallons a year. Still, several experts said Coskata shows enough promise to leave them cautiously optimistic."
Scaling up from a lab size to commercial production will be an awesome task, especially considering the quantities needed.
Just look at how many cars you see on the road as you drive along. And, for instance, each is using ~ 3 gallons per hour. Multiply that by the total number of cars on the road translates into an enormous amount of fuel being consumed.
I do wish them luck, and hope they are successful. Ethanol from corn only returns 30% more energy than that consumed in the process. And that 30% gets whittled away transporting the ethanol to a refinery. And the demand for ethanol from corn is forcing many other commodity prices up — milk, beef and many others because of the competition for the corn. Voo-Doo economics in my estimation. I think the spin is a political football being used to show that we are going to become independent on foreign oil. Twon't happen. And of course, the agricultural community is highly in favor of this, because it increases the demand for their product. And this puts pressure on land space for other crops such as soy beans. Crop rotation is necessary for continuous use of the soil in a productive manner.
- Jack
