Bio Ethanol

Bioethanol

By:

Wisnu Yoga Prasetya 23 KE-2D

Why we need alternative fuels? 

Continuous depletion of limited fossil fuel stock (Global issue).



Ensure protection and betterment of the environment (Global issue).



To be dependent on foreign nations for energy

What is bioethanol? ethanol (ethyl alcohol), a form of renewable energy that can be produced from plants. Ethanol is often used as an additive gasoline so into biofuel. Ethanol can be made ​from common crops such as sugar cane , potato , cassava , and corn.

What are the production schemes for bioethanol? 

Bioethanol is mainly produced in three ways.

1. Direct conversion of

sugar to ethanol 

This is usually done using molasses.

Molasses is a thick dark syrup produced by boiling down juice from sugarcane; specially during sugar refining. As molasses is a by product, ethanol production from molasses is not done in a large scale around the world. The main reaction involved is fermentation yeast

C6H12O6

2 C2H5OH

sugar (e.g.:-glucose)

ethanol

+

2 CO2 carbon dioxide

There are 3 ways

Wet milling

1. 

The process of separating the corn kernel into starch, protein, germ and fiber in an aqueous medium prior to fermentation



The primary products 

starch and starch-derived products (e.g. high fructose corn syrup and ethanol)



corn oil, corn gluten, and corn gluten .

Dry milling

2. 

The entire corn kernel is first ground into flour and the starch in the flour is converted to ethanol via fermentation.



Other than ethanol 

carbon dioxide - carbonated beverage industry



distillers dried grain with solubles (DDGS) - animal feed

Malting

3. 

Steep the corn in water, start germination, stop germination at a particular by drying to stop further growth.

2. Conversion of starch to sugar and then sugar to ethanol 1) wheat

Fermentation conditions

Temperature - 32˚C and 35˚C pH - 5.2.  Ethanol is produced at 10-15% concentration and the solution is distilled to produce ethanol at higher concentrations

2) sugar cane



Simplest of all the processes

• Fermentation conditions are similar to the above process

3) Corn

3. Conversion of cellulose and hemicellulose to ethanol 

4 steps

1.

Pretreatment

2.

Hydrolysis

3.

Fermentation

4.

Distillation of the product mixture to separate ethanol

Challenge for the future Using crops that can be used for food, to produce bio-fuels

Government support of biofuels with tax breaks, mandated use, and subsidies.

land that was also formerly used to grow crops for food is now used to grow crops for biofuels

placing energy markets in competition with food markets

Improvement of the cellulosic ethanol production process

How does environmental impact of bioethanol technologies? 

Positives



Uses energy from renewable energy sources; no net CO2 is added to the atmosphere, making ethanol an environmentally beneficial energy source



Toxicity of exhaust emissions is lower than that of petroleum sources



Energy crops grown for the production of ethanol absorbs huge amounts of green house gases (GHG) released by the burning of fossil fuels.



Ethanol contains 35% oxygen that helps complete combustion of fuel and thus reduces particulate emission that pose health hazard to living beings.



Negatives



Deriving ethanol from crops (eg:- corn) consumes copious amounts of nitrogen fertilizer and extensive top-soil erosion associated with cultivation of this particular crop. 

contamination of the Mississippi River -‘dead zone’

Recent researches 

Manipulate nitrogen metabolism and fixation pathways to reduce the dependence on environmentally damaging fertilizers.



To enhance performance of enzymes, encapsulate enzymes in silicon or carbon nanostructures, providing enzymes with protection from pH and thermal denaturation.



Genetically manipulate Saccharomyces cerevisiae (yeast) so that it can ferment both C5 sugars and C6 sugars