Alternative Fuel

Production of Materials

Most fuel is stored chemical potential energy which can be released normally in the energy form of heat, which is generally used to power our engines, such as cars and generators. Non-renewable energy such as Fossil fuel being our current major alternative fuel has seemingly coming to an end as some believe oil will run out in as little as 25 years. Biofuels such as Ethanol is a renewable sources. Ethanol belongs in the alkanol family also known as alcohols. All compounds in this group have the alcohol function groups “-OH”. Up until about sixty years when the demand of petroleum had greatly raised after world war two for cars. This was when ethanol became available as a by-product for the car motor. Ethanol is not only used as a fuel but is also widely used as a solvent for cosmetics, food colourings and flavourings, some cleaning products and in medical preparation. Ethanol is a clear liquid with a boiling point less than water.

Ethylene can be used to produce ethanol through the reaction with water, the more common ways in doing so are indirect hydration and catalytic hydration. The process of indirect hydration involves reacting Ethylene in absorption columns with about 98% sulphuric acid at a temperatures between 55-80oC at 1-3.5 MPA pressure. Water is then mixed into the reaction until the sulphuric acid concentration is reduced to 50%. From here it is then further heated between 70-100oC. From this point ethanol that has formed is distilled as a concentration of 70%. Catalytic hydration involves passing ethylene and steam through a zeolite or silica gel surface with phosphoric acid or tungstic acid as a catalyst in a pressure range of 1-9MPA at about 300oC. Overtime 97% of the Ethylene will be converted to ethanol.

There are several stages in the production of ethanol through the use of crop. First we need out farmers to grow the crop such as sugar cane and corn which isn't an easy process as they need to be highly maintained with high levels of nitrogen in the soil and lots of water to grow, farmers are put under a lot of pressure not only because they are growing crops for fuel but also to grow crops for food. When the crops are ready they are harvested and the goes in the milling process that involves grinding the crops through hammer mills in to meal which is a fine powder. With all these crops continually growing to meet the demands for food and ethanol and using the same soil over and over again it can loss its organic nutrients and minerals thus it becomes “overworked”. This means the soil is in poor conditions for crops to grow in that soil and may not even grow at all. The second process involves water and enzymes to be added to the meal then goes in a cooker. It is here where the enzymes become active and start to breakdown the complex starch to simple sugars. This mixture is then known as the “mash”.

Fermentation is the third step in this process. Fermentation is a biochemical reaction where sugar (e.g. glucose, fructose, sucrose) is converted into ethanol and carbon dioxide with the use of an enzyme such as yeast. This process has been used for hundreds of years to produce ethanol to make alcohol. When the yeast is added to the mash other enzymes are produced such as zymase, maltase and invertase. These enzymes carry out complex reaction changing sugar into ethanol and carbon dioxide. Fermentation requires a specific environment of a temperature of about 37oC a PH of 3.6-4.7; it takes about 3-5 days for fermentation to be complete.

Distillation is the second last stage towards pure ethanol in this process the mash which is now known as beer is 10% ethanol, the other 90% is non-fermentable solids. The beer is then placed in the distillation chamber where the ethanol is separated from everything else. The final stage the ethanol runs through a dehydration chamber to remove excess water giving an end result of pure ethanol. Being that ethanol is produced from crops such as corn, wheat and sugar cane, and alot of food is made from these products such as bread, cereals, pasts, the list goes on, food prises will rise due to the greater demand for these crops.

The two main producers of ethanol are the United States and Brazil (does not need to rely on imported gasoline). Other countries like china, India, Canada, European and Australia also produce ethanol but not as much as the first two countries mentioned, but over time they will catch up.

Ethanol can be used as a fuel to run a motor that has been designed for it. Ethanol does burn cleaner than petroleum, but more ethanol is needed for a car to travel the same distance as a car running on petroleum. Ethanol can be corrosive if not filtered properly before combustion. Using ethanol has more of a negative than positive in using it as a fuel.

In conclusion ethanol will ultimately be a bad alternative fuel for the environment as more of it is need to run an engine than what fossil fuels needed creating more pollution as well as ethanol being more expensive than petroleum. A significant prise rise in foods. There is a restriction on how much crop can be produced due to land management.


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