ZeaChem In Long-Term Poplar Tree Feedstock Supply Agreement for Biorefinery
11 February 2008
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| Elements of the ZeaChem process. Click to enlarge. |
ZeaChem, Inc. and GreenWood Resources, Inc. (GWR) signed a non-binding Letter of Intent for the supply of poplar tree (Pacific Albus) feedstock under a long-term agreement to support the operation of an initial 1.5 million gallon per year (MGPY) ZeaChem cellulosic biorefinery near one of Greenwood’s Pacific Albus tree farms in the Columbia River Basin.
The ZeaChem biofuel process combines the outputs of two traditional fuel production pathways (fermentation of sugars and gasification of biomass) into a third catalytically-driven step—hydrogenolysis—to produce cellulosic ethanol fuel and cellulose-based intermediate chemicals. ZeaChem’s technology will produce 50% more ethanol per ton of feed than the current best-in-class technology. (Earlier post.)
The biochemical processing step converts sugars in the cellulosic biomass into acetate via bacterial fermentation. The conversion can be either direct in a one-step fermentation process or via lactic acid to acetic acid in a 2-step process. (The production of lactic acid can provide an additional revenue source.) After fermentation, the acetic acid is extracted from the fermentation broth in an acid recovery stage and esterified.
The thermochemical processing step converts lignin and other non-fermentable materials in the cellulosic biomass into a syngas. The acetate ester from the fermentation pathway and the hydrogen from the syngas combine in a hydrogenolysis reaction to produce the ethanol.
An analysis of the ZeaChem process included in a report on ethanol by the University of Illinois, published in November 2007, notes that:
In this process, 3 moles of ethanol are produced from 1 mole of glucose resulting in a 50% improvement over the conventional route where 2 moles of ethanol are produced from 1 mole of glucose. The energy for the third mole of ethanol is supplied by hydrogen, which can be generated by the gasification of the lignocellulosic biomass.
Zeachem also uses the thermochemical processing stage to provide steam and power for the plant.
Additionally, ZeaChem and GWR agreed to explore increasing the scope of the relationship to accommodate additional capacity at this biorefinery and other future sites through the potential development of short-rotation poplar biomass energy tree farms integrated with ethanol conversion technology.
ZeaChem will be responsible for financing, constructing and operating the biorefinery. Initial engineering for the site has already begun.
GreenWood Resources (GWR) is a leader in the development and management of short-rotation, high-yield hardwood tree farms for a range of products and end uses. The GreenWood Tree Farm Fund, LP (GTFF), a $175-million fund organized by GWR, has invested in the consolidation of existing high-yield, fast-growing tree farm assets in the Pacific Northwest.
GTFF currently owns 35,000 acres of sustainable tree farms certified under FSC in the Columbia Basin in Oregon and Washington.
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Something's funny about that diagram. Esterification is a reaction between an acid (in this case acetic acid), and an alcohol (in this case 3 moles of ROH that appear out of nowhere, and then reappear as a side product of the final hydrogenolysis step). Are those moles of non-ethanol alcohol simply reused as a component of this reaction? And if so how are they separated at the end?
On the upside, the organic layer of acetate ester should be easily separable from the water after esterification.
Posted by: AES | 11 February 2008 at 12:27 PM
The alcohol used to make the ester is simply more ethanol. So, after hydrogenolysis, most of the ethanol is recycled back to complete the cycle, while the net production is removed. There is no need to separate two different kinds of alcohol.
Posted by: Paul Dietz | 11 February 2008 at 12:49 PM
If ascetic acid is a biproduct, why not make butanol?
Posted by: Healthy Breeze | 11 February 2008 at 01:35 PM
The ascetic acid all went to the monastery and took vows of poverty and silence.
Posted by: Reality Czech | 11 February 2008 at 01:52 PM
This is yet another scheme to get some federal subsidy money and feel-good investors. Technologies like this sound fun and cool but the economics never will work. If you want bioenergy just burn these trees. Add a few scrubbers and make sure the exhaust gasses are clean. Some carbon will be trapped in the clinkers and ash so it will be carbon negative most likely if operations are efficient. The added benefit of burning versus several rounds of chemical processing where energy is wasted at every step is that you get a whole lot more energy than converting it to liquid fuels.
If we want to fix the transportation problem we need to stop focusing only on scientific solutions. Alternatives are ready if we just had a political solution. Every time I look around at vehicles around me in the US I think the cart is in front of the horse. If we can’t reduce gasoline consumption now how will put into action more expensive projects in the future. Scientists aren’t gods and alternatives aren’t without tradeoffs.
Posted by: Mike H | 11 February 2008 at 02:10 PM
I once said that they could use enzymes to make cellulose ethanol and whatever is left could be gasified to make more.
Someone (no names) said that it would be too wet and not possible or at least not cost effective. hmm...
Posted by: sjc | 11 February 2008 at 04:35 PM
Mike,
Scientists are no gods and must be wondering why people want to spend so much time sitting in traffic snarls. The answer is that so much of our work is based on the margins gained from exhausting natures bounty of fossil fuels on the slim claim of participating in "the economy".
Psychologists from Mars would be quite sure the human inhabitants are definitively quite mad.
The race to condemn their environment would support their analysis.
While the systems in place encourage business as usual, there will be institutional resistance to change.
This is a major part of the problem, as such will not find a 'cure' in any realtech toolkit.
Posted by: Arnold | 11 February 2008 at 05:30 PM
Arnold
Mike is right, at best bio fuel could cover 30% of our national need, ok. But designing fuel efficient car could slash 50% of our gas coonsumption (even more if you believe Rocky Mountain Institute). It is propably easier to double average mileage in america (given that they are so poor compare to other countries) than to developp a cellulosic ethanol inductry that can produce 35 billions gallons of ethanol a year. But still we putting more money in the later than in the former...just to keep GM in business probably
Posted by: Treehugger | 11 February 2008 at 08:24 PM
It should be both. More efficiency and alternate energy. We will have to do everything we can to make it better, but that will take leadership and we seem to be waiting for that right now.
Posted by: sjc | 12 February 2008 at 07:05 AM
Multitasking is OK. Work can be done on several pathways at the same time. That is the benefit of distributed creativity. We don't know what the solutions for the future are yet.
As my novice master said when I was a seminarian: "All we can do is make mistakes. If something doesn't work out, we'll just try something else."
The following year I transferred to a different seminary, where everybody was so terrified of making mistakes that no decisions were ever made, resulting in paralysis of the system.
Posted by: fred schumacher | 12 February 2008 at 03:39 PM
This is the advantage of an intellect. You model the situation, use your knowledge and experience and make as few mistakes as possible. The mistakes you make should be small and if they are not, you need to examine where you went wrong so that you do not make the same nor similar mistakes again. This seems more like logic than philosophy. We may not get to perfection, but the continuous refining to get closer should be our objective.
Posted by: sjc | 12 February 2008 at 04:05 PM
It's an improvement on the previous plan of just burning the poplar tree wood.
Posted by: John Taylor | 13 February 2008 at 03:41 AM