Bioethanol Production

It seems that Biodiesel has been getting all the press recently leaving Bioethanol largely unexplained and feeling somewhat left out. I find the lack of details for Biothanol quite disturbing. So after a question that was posted on our forum, I have decided to dedicate a page to explaining the production and use of Bioethanol.

What is Bioethanol
The principle fuel used as a petroleum substitute is bioethanol. Bioethanol is mainly produced by the sugar fermentation process, although it can also be produced by the chemical process of reacting ethylene with steam. The main source of sugar required to produce ethanol comes from fuel or energy crops. These fuel crops are normally grown specifically for energy use and include maize, corn and wheat crops, waste straw, willow, sawdust, reed canary grass, cord grasses, jerusalem artichoke, myscanthus and sorghum plants. There is also ongoing research and development into the use of municipal solid wastes to produce ethanol fuel.

Brazil and the United States account for over 70 percent of all ethanol production in the world today with the USA producing an estimated 6,500 Million gallons a year

The Advantages of bioethanol

Price
The price of bioethanol / petrol fuels will be kept low due to government subsidies and lower rates in tax. This has shown to encourage the use of a cleaner fuel, assuming public interest is sufficient to create a significant market in alternatively fueled bioethanol and alcohol cars.

The Environment
Bioethanol produces only carbon dioxide and water as the waster products on burning, and the carbon dioxide released during fermentation and combustion equals the amount removed from the atmosphere while the crop is growing.

How is Bioethanol used / Bioethanol Blends
Ethanol is most commonly used to power cars although it is also used to power other vehicles, such as tractors, airplanes and boats. Like Biodiesel, engine old starting can be effected when using high blends of Bioethanol fuel in cars. EU markets have adopted E85 (85 percent Ethanol / 15 percent Gasoline) as the maximum blend to be used and this is the common standard which manufactures work to when making their cars run Bioethanol or “flexi-fuel”. In some colder climate its it recommended that an E70 blend is used.

A new type of fuel, SP95-E10 (Sans Plomb 95 Octane, Ethanol 10% = Lead Free 95 Octane containing 10% of Ethanol) is now being sold throughout France.

This fuel is not suitable for use in all cars and you should check compatibility with your vehicle manufacturer before using it. If in doubt use the standard SP95 or SP98 Octane unleaded fuel which continues to be available alongside the new fuel.

How Bioethanol is made
The basic steps for large scale production of ethanol are: fermentation of sugars, distillation, dehydration and denaturing (optional). Prior to fermentation, some crops require saccharification or hydrolysis of carbohydrates such as cellulose and starch into sugars. Saccharification of cellulose is called cellulolysis (see cellulosic ethanol). Enzymes are used to convert starch into sugar.

Fermentation
Ethanol is produced by microbial fermentation of the sugar. Microbial fermentation will currently only work directly with sugars. Two major components of plants, starch and cellulose, are both made up of sugars, and can in principle be converted to sugars for fermentation. Currently, only the sugar (e.g. sugar cane) and starch (e.g. corn) portions can be economically converted. However, there is much activity in the area of cellulosic ethanol, where the cellulose part of a plant is broken down to sugars and subsequently converted to ethanol.

Distillation
For the ethanol to be usable as a fuel, water must be removed. Most of the water is removed by distillation. The purity is limited to 95-96% due to the formation of a low-boiling water-ethanol azeotrope. This may be used as fuel alone but unlike anhydrous ethanol it is immiscible in Petrol meaning it can not be mixed i.e. E85. The water fraction is typically removed in further treatment in order to burn with in combination with petrol in petrol engines.

Dehydration
Currently, the most widely used purification method is a physical absorption process using a molecular sieve, for example, ZEOCHEM Z3-03 (a special 3A molecular sieve for EtOH dehydration). Another method, azeotropic distillation, is achieved by adding the hydrocarbon benzene which also denatures the ethanol (to render it undrinkable for duty purposes). A third method involves use of calcium oxide as a desiccant.

Can I produce Bioethanol at home?
There are many people producing Bioethanol at home for their own use. Many people opt for a home made “still” for the production process however obtaining a consistant proof can be very hard for most inexperienced producers

The market Biothanol Processors is not like the highly competitive Biodiesel market, I believe that this is due to the fact that many of todays cars are still not capable of running a Bioethanol Mix i.e. E85 for day to day use.

Bioethanol from Algae

Researchers have recently launched a proposal to cultivate massive amounts of seaweed  or algae. They laims that the project could occupy about ten thousand kilometers of seaweed farm and they estimated that the farm would be able to produce bioethanol from algae, as much as 20 million kiloliters or 5.3 billion gallons of bioethanol per year. This amount equal to a third of Japanese fuel consumption a per year.

Seaweed / algae has already been proven to be capable of becoming an alternative option for producing biofuel.  Most of the biofuel today is produced from food stock which hasits  own disadvantage and the ratio of the crops and the amount of ethanol that it produces is not balanced. Some suggest that the using of food stock for bioethanol production has caused food prices to rise.

This would be then processed by floating bio reactors. Facilities that would use enzyme to breakdown the seaweed into sugar which would then be processed and be converted to ethanol. This process will take place on the sea and would be then transported to land by tankers.

What are the advantages of using algae / seaweed for bioethanol production?

  • It doesn’t need soil or freshwater and other producer substances. It is naturally occurring in the sea and there would be no imbalance that would happen when it is harvested.
  • We would be able to avoid the food price hike if we would utilize this new technology for we will no longer be taking away lands to farm crops.
  • Algae / seaweed grow unbelievably faster. Around 10 times as fast as sugar cane. It is actually the fastest growing crop known to man.

 

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