Last Summer I brought you word of the potential for ethanol made from woody crops such as poplars with a yield of up to 2,000 gallons per acre… per acre. That’s enough fuel for something like 3 average cars per acre per year. On top of that, the process could result in ethanol cheaper than $1.00 per gallon without any government support.
And today ZeaChem, the company behind this groundbreaking process, announced that they have successfully completed a crucial step in converting wood to ethanol, proving that their core technology works and is commercially viable.
The ZeaChem process goes something like this (illustrated in the above diagram):
- Woody biomass (e.g. hard- and softwood, grasses, corn stover, etc.) goes in one end.
- That woody stuff gets chemically separated into two groups: sugars and “everything else.”
- The sugars are sent to a fermentation tank where, using nothing but already existing and proven microbes, they are fermented into acetic acid. A key benefit of this type of fermentation over traditional fermentation with yeast that you see in corn ethanol facilities is that it produces no carbon dioxide. Yeast fermentation produces one molecule of CO2 for every molecule of ethanol. You can see the problem there.
- The resulting acetic acid then goes through a process called esterification to convert it to ethyl acetate.
- The residue of “everything else” that is left over from the initial chemical separation is then gasified and turned into hydrogen and other syngases.
- The hydrogen is then combined with the ethyl acetate to make ethanol in a process called hydrogenation.
- The other syngases are burned to generate the necessary steam and electricity needed to run almost the entire process from beginning to end.
All of the above chemical reactions and processes have been used in other industrial applications for a long time and so are quite robust. The only one of them that ZeaChem had yet to prove would work commercially was the esterification. Hence with the announcement today, that process has been successfully completed and the results certified by an independent 3rd party, Sulzer Chemtech.
What’s particularly interesting about the ZeaChem process is that, in-and-of-itself, ethyl acetate is a saleable product — accounting for a $2.2 billion dollar global market. So even without the final conversion to ethanol, or in the face of low ethanol demand, ZeaChem has an “out” to continue selling product. ZeaChem claims that their ethyl acetate is just as good as the stuff produced from crude oil, but that it can be made for much cheaper and is completely renewable.
ZeaChem is in the process of building a 250,000 gallon per year demonstration plant in Boardman, Oregon, which is scheduled to come online this year. The Boardman facility will be fed by woody biomass from a nearby hybrid poplar plantation run by GreenWood Resources.