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ZeaChem Raises $34M for Indirect Ethanol Process Biorefinery

Elements of the ZeaChem process. Click to enlarge.

ZeaChem Inc., the developer of an indirect process for the production of cellulosic ethanol, raised $34 million in initial Series B financing. The funding round was co-led by venture capital investors Globespan Capital Partners and PrairieGold Venture Partners with follow-on investment by MDV-Mohr Davidow Ventures, Firelake Capital and Valero Energy Corporation, the largest petroleum refiner in the United States.

ZeaChem’s process combines the outputs of two traditional ethanol production pathways (fermentation of sugars and gasification of biomass) into a third catalytically-driven step—hydrogenation—to produce ethanol. (Earlier post.) Zeachem now says that it can produce 40% more ethanol per ton of biomass over any known competitor. The company will use the new funds to build its first cellulosic biorefinery this year.

In the ZeaChem process, the biomass is chemically fractionated to produce a sugar stream containing both xylose (C5) and glucose (C6) sugars, and a lignin residue stream.

The sugars are fermented by a carbon-efficient acetogen—Clostridium thermoaceticum, found in termites—to acetic acid without CO2 as a by-product. (Conventional yeast fermentation creates one molecule of CO2 for every molecule of ethanol.) The acetic acid is converted to an ester which is then be reacted with hydrogen to produce ethanol.

The hydrogen is produced by the gasification of the lignin residue to produce syngas. The hydrogen is separated from the syngas and used for ester hydrogenation and the remainder of the syngas is burned to create steam and power for the process. The net effect of combining the two processes is that about 2/3 of the energy in the ethanol comes from the sugar stream and 1/3 comes from the lignin steam in the form of hydrogen, according to ZeaChem.

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 says that it expects to be able to deliver an Nth plant yield of 135 gallons of ethanol per bone dry ton (BDT) of biomass.

In February 2008, ZeaChem 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. (Earlier post.)




I pass on the observation that the output from (partcuarly non food) ethanol/bio fuel plants seems to be either side of the 1 liters /ton.
A few years ago I was one keeping my head down making 'ooh' and 'ah' noises and tyring to figure how output can be higher than input. (as long as "waste nuclear process heat is supplied")
Like so many hype promises that simply cant deliver.
I'd be a rich man if even a few had. But I'm in front because (my) times more valuable ... for listening to crickets..

This seems an example of the composers art. While so many focus on the 'competitive advantage' of system x over system y that the idea that we can have both and in combination is a bit unusual.

The 'more' that should be practical in the future for this plant sees the residue 800? kilo turned to pyrolosis,charcoal, fertiliser or other biological product or a plastic component.
With a focus on supplying process heat from primary (wind geo, as appropriate) renewable or other (waste) heat sources.

Any opportunity realised in these area will add economic diversity and efficiency in the same way as other (fossil fuel industry) integral economics. And the Efficiency drive for energy use and emission reduction.

This would of course be dependent on these technologies and integration opportunities being available .

Although there are many challenges to the seamless or smooth operation of this plant, leading to a perception view of a slow and difficult process for modest returns, We should remember that as fossil fuels are not being replaced, the ability to step across to a new 'orbit(s)' will not present very often and as the conditions for industry become more difficult, these opportunities diminish.

I am encouraged when ways are found to leverage the benefits from integrating the various 'competition' by working together.
Unfortunately the human condition? economics? selfish gene? has not evolved universal tools to (smooth) enable this direction.

But then necessity is the mother of invention.


I know i said 100 liters/ton'


This raises more questions than answers. Here goes.
How does it compare to Coskata's claimed EROEI of 7.7?
What is the volumetric ratio of water input to fuel output?
Where does the waste go?
Can the process produce more energy dense fuel than ethanol?
Why not just sell the hydrogen separately?
How much will it cost per litre or gallon?


Compared to Coskata's?

The original GCC reference 2nd july 2007 states:

The Zeachem process thus can use all fractions of the plant—cellulose, hemicellulose, and lignin—producing much higher yield per ton of feedstock.

Because the yield is so much higher and because energy integration is tighter, the ZeaChem process is friendlier to the environment, according to the company. Ethanol produced by corn dry milling in the US has a net energy ratio of less than 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, ZeaChem claims a net energy ratio of 10-12.

Started a comment on post GCC 9th jan 2009: 'Idaho Nat lab carbon efficient high temp steam electrolysis'

where the hydrogen is supplied from high temp waste or other nuclear plant heat
but it fits better here. Supporting what I hope I conveyed in my previous comment.
Although more efficient at carbon conversion, is it a likely candidate for appropriate tech?

Problems with factoring in 'waste?' heat or Nuclear energy sources center on scalability to approach widespread implementation:

Nuclear power is unlikely to be readily available on a global scale
supply constraints would soon become apparent if the logistics were resolved.

On my reading, the ideal siting of the plant adjacent to the power plant rather than connected via a grid (although not excluded) for max efficiency. Nuclear (and other gigawatt plants) are usually located in high population dense areas as opposed to forestry or agricultural areas and certainly not in agriculture dependant countries that have limited capital or requirement for generators on grand scale. This would further disadvantage those areas already underdeveloped.

If the high temp electrolysis plants were to become widespread for the purpose of supplying liquid fuels, there would be (continuing ) rapid cost and fuel supply issues with the chain logistics and depletion of resource becoming apparent in linear relation to the success.

With increasing demand for energy for all applications It would seem an advantage to concentrate on technologies that emphasise the utilisation of biological process with renewable energy.

While it would seem obvious that we need better working models, the more successful applications relying on conventional finite resources, the faster these deplete. Short term measures often become the only economically viable options while the requirement for civilised society remain beyond the reach of the increasing majority. That does not suggest a healthy market direction.


This process is very smart, a true work of art of engineering but complex and won't be cheap to implement. The fact that we are seeing so many different approach being experimented for conversion of biomass to biofuel tells me that the technology is still in its infancy and won't produce any significant amount of fuel anytime soon. Anyway a very centralised approach based on huge complex plant is a dead end because of the poor energy density of biomass. If you have to carry the biomass over tens of miles then biofuel will stay what they are : virtual.

Again a 1 million ton/year biofuel plant would requires a truck of 30 tons of biomass every 6 minutes 24hrs/day, 360 days/years. Don't even think about it

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