Replies

What is the procedure for producing ethanol from wood?

I am coming to the conclusion that making ethanol from wood(cellulosic ethanol) is far more expensive than making methanol from wood and other cellulose sources. Ethanol at this point is what gets made when certain bacteria(yeast) eat sugars. Methanol is what gets made when other bacteria eat cellulose. Getting cellulose into a form that can be eatin by yeast takes several added steps that cost a lot of extra money that methanol production doesn't have to worry about or pay for. From wiki:

Cellulosic ethanol (also called lignocellulosic ethanol) is a type of biofuel produced from lignocellulose, a structural material that comprises much of the mass of plants. Lignocellulose is composed mainly of cellulose, hemicellulose and lignin. Corn stover, switchgrass, miscanthus and woodchip are some of the more popular cellulosic materials for ethanol production. Cellulosic ethanol is chemically identical to ethanol from other sources, such as corn starch or sugar, but has the advantage that the lignocellulose raw material is highly abundant and diverse. However, it differs in that it requires a greater amount of processing to make the sugar monomers available to the microorganisms that are typically used to produce ethanol by fermentation. Switchgrass is the major biomass material being studied today, due to its high levels of cellulose. Cellulose, however, is contained in nearly every natural, free-growing plant, tree, and bush, in meadows, forests, and fields all over the world without agricultural effort or cost needed to make it grow. Whether distilled from agricultural crops such as corn, wheat, barley or created from celloluse, ethanol is ethyl alcohol; it is identical in chemical composition regardless of the source. Calling it cellulosic ethanol is misleading because it (cellulosic ethanol) is no different physically from corn ethanol or wheat ethanol. The ground of North American forests is littered with tons of cellulose-containing wastewood branches fallen from trees, which could be harvested and converted into ethanol automobile fuel. The processes that produce lumber and lumber products also generate cellulose waste that is discarded that could be used to produce cellulosic ethanol.

There are at least two methods of production of cellulosic ethanol (see "Production methods", below):

Cellulolytic method: hydrolysis followed by fermentation of the generated free sugars.
Gasification, which produces synthesis gas that can be converted to ethanol by fermentation or thermochemical catalysis (e.g., the Fischer-Tropsch process).

Neither process generates toxic emissions when it produces ethanol.

Cellulosic ethanol production currently exists at "pilot" and "commercial demonstration" scale, including a plant in China engineered by SunOpta Inc. and owned and operated by China Resources Alcohol Corporation that is currently producing cellulosic ethanol from corn stover (stalks and leaves) at a continuous, 24-hour per day rate.

Yeah, what #121 says. There are actually 2 ways. One way uses bacteria similar to what a termite does in it's stomach. The hold back there is the bacteria must be manufactured and multiplied. Another similar method just manufactures the enzyme that digests the cellulose into ethanol. Very expensive to manufacture tons of it and it can't be used over and over. Making ethanol from sugars just requires yeast to continue to multiply.

The 2nd method is to make syngas from the feedstock( coal, cellulose,etc) and then change it into ethanol. The big variable here is the energy input to make syngas. There are several companies that manufacture the equipment to do method #2. If you have 5-10 acres, a source of saw dust or wood chips, or coal,( or for that matter nat gas), and a power source, you too can make your own ethanol from wood, trash, coal, etc. The problems still remain, how much is the feedstock, how much does the energy input cost, and how much is the going price of ethanol? When ethanol was $4 a gallon, this was very positive. Now corn is high and ethanol is low which is the same problems oil refiners have at the moment. They call it "the crack spread". The answer, of course, is to get a cheaper feedstock, like sawdust or switch grass. And maybe some type of solar or coal powered energy source. As long a pols from Iowa control the process, this will be unlikely. They insist corn is the ONLY way America will go. They also still insist on subsidies when corn is at an all time high. We can buy 200 proof ethanol from Brazil for about $1.50 dollars a gallon,RIGHT NOW, But the US tacks on about 57 cents a gallon tax to keep it out of our market. We also give sugar subsidies to US farmers to keep the price of sugar propped up when it could be produced much cheaper and, ergo, make ethanol from sugar for less than $1 a gallon. Ethanol is workable, right now, but there are so many competing forces working against it, it looks bleak. Also, American ignorance on the subject is beyond belief. If we don't crack the corn cabal soon, ethanol as fuel, will die and Brazil will keep moving forward past oil independence, to oil exporter. Ethanol is the fuel answer, but corn ethanol from US farmers, is killing the idea. What if we bought corn from Russia, or Brazil? The farmers here would still pitch a function and you still have a tight energy profit. We must move on or ethanol will die.