One of the man's oldest pastimes has been making alcoholic drinks from fermented plants.But today,as oil is running out and its price is high, alcohol from plants is being put to another use-providing an alternate fuel for vehicles.World's largest producer of fuel alcohol from plants is Brazil.
When crisis occurred in 1973,Brazil launched its alcohol program in two years,in response to the increasing costs of importing fuel.They use a raw material with a low market value and which they grow in abundance(sugar cane).
Initially the process is same whether the end product is to be an expensive brandy,or fuel alcohol which can drive a car.
Procedure: Raw sugar is mixed with water and yeast and fermented in large tanks,until it turns into an alcoholic liquid,rather like wine or beer.
100%(200 proof) alcohol is needed for fuel,so to concentrate the mixture it is distilled.This is done by heating the liquid to vaporise the alcohol,then condensing the vapour to extract the alcohol and leave the water behind.This last stage,to produce anhydrous alcohol,needs a lot of energy,and has led criticisms that producing fuel in this way can actually consume more energy than it provides.
Despite this alcohol production in Brazil has boomed.More than 80% of cars sold in Brazil now run on pure alcohol,or a mix of alcohol and petrol,and the bill for imported oil is down by about $2 billion a year.Annual production is over 11 billion litres and will need increase by another 2 billion litres to keep up with demand.
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