March 13, 08
Cellulosic Biomass Into Vinegar Makes For $1.50 a Gallon Ethanol

ZeaChem technology has perfected a new process that could change the landscape of ethanol production and and end the competition between food and energy in the world of agriculture. Their process uses Vinegar to transform virtually any form of biomass into a cheap renewable form of ethanol. By 2010, the company hopes to be producing ethanol commercially for 80 cents a gallon at wholesale, which translates to anywhere from $1.10 to $1.50 at the pump.

The innovative biochemical processing converts fermentable sugars in the cellulosic biomass into acetic acid (Vinegar), which is then recovered from the broth as an ester. The thermochemical processing step converts lignin and other non-fermentable materials in the cellulosic biomass into hydrogen. By combining these two streams in a hydrogenolysis reaction, ZeaChem produces ethanol. Unlike other processes, the Zeachem process uses all fractions of the plant - cellulose, hemicellulose, and lignin, giving it much higher yield.

Their approach allows both fermentable and non-fermentable fractions of the feedstock to contribute chemical energy to the ethanol product. Other approaches have theoretical restrictions that limit ethanol production to 60-100 gallons per dry ton of biomass. The ZeaChem technology will produce fifty percent more ethanol per ton of feed than the current best-in-class technology. Our higher yield dramatically improves process economics, allowing farmers to get more ethanol out of each acre of biomass crop.

Because the yield is so much higher and because energy integration is tighter, the ZeaChem process is friendlier to the environment. Ethanol produced by corn dry milling in the US has a net energy ratio of under 1.6, meaning that fewer than 1.6 units of renewable energy are produced for each unit of fossil energy used in the production the crops and conversion of the crops into fuel ethanol. In contrast, the ZeaChem technology enables a net energy ratio of 10-12. Such high values fundamentally change the nature of any policy debate on the environmental aspects of ethanol as a liquid transportation fuel.

The biochemical processing step can ferment any fermentable sugar, including simple sugars like those found in sugar cane juice, more complex sugars found in corn starch, and the mixed sugars commonly found in cellulosic hydrolyzates. Any material that isn't readily fermented, such as lignin, can be processed via thermochemical means to produce hydrogen. The result is that the ZeaChem technology is highly flexibile and can be implemented anywhere in the world.