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A new pretreatment process, eliminates expensive toxic acid baths in favor of ammonia. The treatment will help produce cheaper ethanol from plant waste, like these corn stalks shown here.  (Source: 3media.com)

Bruce Dale, University Distinguished Professor of chemical engineering and materials science at Michigan State University invented the cheaper and more efficient AFEX cellulosic ethanol pretreatment process, with the help of his doctoral student Ming Lau.  (Source: MSU)
A new process invented by Michigan State University helps to increase the yields of cellulosic ethanol at a reasonable premium

The world of cellulosic ethanol is a hot business.  GM has already backed two cellulosic ethanol companies, Coskata and Mascoma Corp., and many others are taking a serious look at the new type of fuel.  Essentially with the same advantages and disadvantages from a fuel perspective as normal ethanol, which it shares virtually the same chemical character with, the big bonus is that cellulosic ethanol can be made from plant waste of all times, reducing the price pressure produced by food-crop ethanol.

Using technology to produce cellulosic ethanol, the fruits and vegetables of food crops can ship to the market and the leftovers -- leaves, stalks, stems, and husks -- can be ground up and made into ethanol.  One of the first targets is corn stover, the leftovers from the corn harvest, somewhat of an ironic source as sugarcorn (the food) became one of the two main controversial sources of food-crop ethanol

Unfortunately, the processes to make cellulosic ethanol are still very inefficient.  And while there are acid pretreatments that can improve the performance, freeing up more sugars from the cellulose and hemicellulose in plants to be used in fermentation, these treatments are costly.  Typically the acidic product is toxic, so it must undergo intensive washing and detoxifying, leaching nutrients that could have been used in fermentation and raising the costs.

That's where Michigan State University comes in with a new patented process.  Bruce Dale, University Distinguished Professor of chemical engineering and materials science at the university, has invented a cheap pretreatment process using ammonia, called AFEX (ammonia fiber expansion).

Its 75 percent more efficient than with traditional enzyme treatments says Professor Dale, and is easier and more affordable than acid pretreatments.  The process frees up a lot of sugar to be used in the fermentation to produce more ethanol.

Professor Dale states, "Doctoral student Ming Lau and I have shown that it's possible to use AFEX to pretreat corn stover (cobs, stalks and leaves) and then hydrolyze and ferment it to commercially relevant levels of ethanol without adding nutrients to the stover.  It's always been assumed that agricultural residues such as corn stover didn't have enough nutrients to support fermentation. We have shown this isn't so."

He states, "Washing, detoxifying and adding nutrients back into the pretreated cellulose are three separate steps.  Each step is expensive and adds to the cost of the biofuel. Breaking down cellulose into fermentable sugars cost effectively has been a major issue slowing cellulosic ethanol production. Using AFEX as the pretreatment process can dramatically reduce the cost of making biofuels from cellulose."

Ming Lau, a coauthor of the project who shares the patent with Professor Dale adds, "The research also shows that the chemical compounds created when the stover goes through the AFEX process can improve the overall fermentation process.  This is at odds with the general perception that these compounds are detrimental and should be removed."

The pair is looking to set up a pilot plant at MBI International, a subsidiary of the MSU Foundation.  However, they already are also attracting commercial interest.  States Professor Dale, "There are several companies – including the Mascoma Corp., which plans to open one of the nation's first cellulosic ethanol plants here in Michigan – that may be interested in using this technology.  We are working to make the AFEX technology fit these companies' needs."

The new research is published in the current issue of Proceedings of the National Academy of Sciences (PNAS). 

The work was funded by the GLBRC, the MSU Research Foundation, and the Michigan Agricultural Experiment Station.  



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RE: I hate ethanol
By blowfish on 1/22/2009 11:24:55 PM , Rating: 3
It's going to be tough to dismantle the Ethanol "industry" that has been set up to benefit the farmers. Since considerable energy has to be spent converting the cellulose to sugar, you would think that the first ethanol plants would have been set up in sugar-growing states - but I guess the Louisiana and Florida politicians just weren't wise to it. Brazil, that has been a major ethanol user for decades, uses a sugar-based production process.

Some "patriotic" twat might chip in and say that the US is more high-tech than Brazil - maybe that's why the US uses a less efficient process!

I always log my mileage on every tank of gas. I always reset the trip meter, and fill the tank right up. My conclusion - Gas with 10% ethanol is not worth using! If you have a choice, don't buy it. It would be very effective if consumers voted with their feet (or wallets)

In Europe, there's a similar situation with "City Diesel", which is formulated with some vegetable oil content. Whether it's due to lower calorific content or some adverse affect on engine tuning, the nett result is to cause the engine to produce noticeably less power, and to get measurably worse gas mileage.

As to the ridiculous argument that not using ethanol would mean we would have to buy more oil from our "enemies" - the potential reduction in oil usage from a bit of conservation and decent high-mpg design would easily outweigh any benefits from ethanol use.

The future is not ethanol - the future is battery electric, and when battery technology is up to it, even the speed-freaks will be happy. You can do things with electric propulsion that are just not possible with I.C.

Make this one of your New Year Resolutions for 2009 - I will not buy gas containing ethanol if I can possibly avoid it!


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