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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 Gzus666 on 1/22/2009 9:30:49 PM , Rating: 2
quote:
Text Are you nuts? Boost the compression to 17-18:1 and that might well be the last tank of gas that engine ever sees.


Alcohol likes high compression, granted you have to beef other things up to make it handle the higher pressure, but that should be obvious. 13:1 compression ratio is more than common in higher performance vehicles people make, it is actually really common. I have seen people run mid 14:1 compression on 93 octane. Alcohol has a high octane, around race gasoline, so it is not unheard of or even obscure to expect that kind of compression from it.


RE: I hate ethanol
By JediJeb on 1/23/2009 3:56:49 PM , Rating: 2
It is why most people wont run Propane in a gasoline engine like they tried in the mid 70's. In a regular engine with say 8-10:1 compression you get terrible milage and power, with compression of 14-16:1 you get milage and power on par with gasoline.

As to the corrosion and damage problems mentioned above, that is usually from Methanol in the gasoline not Ethanol. Methanol was used from in gasoline up through the late 90's early 00's then was replaced with ethanol. Methanol will ruin injectors and seals quickly in anything over 5% concentration. It also causes pitting on aluminum.

Of course diesel engines run in the 22:1 compression range, so compression alone won't kill the engine if you design it right. For Ethanol to succeed as a fuel, it will take cars with engines optimized for it, and if you wait till the Ethanol is cheap to produce you will have fuel noone will buy, and by the time the engine technology catches up the ethanol plants will be bankrupt, then the engines will be useless, ect ect. You have to start somewhere, so make the fuel, then optimize the engines, make better fuel, make better engines ect and all will work out. ( I guess it's sorta like the switch from analog to digital TV, you try to do it all at once and it causes a panic, but since it has happened over the last few years, the final switch won't be as bad)


RE: I hate ethanol
By Fnoob on 1/26/2009 9:48:13 AM , Rating: 2
I was referring to gasoline engines, not specialized race cars. I think my statement stands that with a standard gasoline engine, if you increase it's compression ratio from 10 to 18 you will significantly decrease the life expectancy of the engine due to substantially increased heat. Now, a specially constructed and reinforced engine designed to run these new fuels is a totally different story.

However, as another poster mentioned, I had no idea that diesel motors ran such high compression. Guess it should have been obvious, since they achieve ignition through compression.


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