– (Gabriel Silveira/)
Ethanol (or ethyl alcohol) is produced in plants from raw materials such as sugar cane, corn or beet. It is a biofuel, that is, a renewable fuel, which does not need materials of fossil origin, such as oil. Around the world, biofuels have always been in the background due to the ease of extraction of petroleum and due to its abundance. The problem is that burning fossil fuels contributes to global warming. And, as there are already signs of oil shortages, ethanol has begun to gain more attention. However, not every biofuel is such a clean alternative for the planet. Due to the complexity of its manufacture, ethanol can, depending on the raw material, even generate more polluting gas emissions. Not to mention the risk of further deforestation to expand plantations. In this regard, Brazilian ethanol, made from sugar cane, has an advantage. It is more productive than that extracted from corn, for example, and causes a smaller environmental impact. While one hectare of corn yields 3,000 liters of ethanol, the same area planted with sugarcane generates 7,500 liters!
– (Gabriel Silveira/)
1) The main raw material for Brazilian ethanol is sugarcane. It arrives at the plants in trucks and is unloaded on conveyor belts. The first stage of production is the washing of the sugarcane, which receives a water bath that removes earth, sand and other impurities.
– (Gabriel Silveira/)
two) After being washed, the cane is chopped into small pieces to facilitate grinding. Here it also passes under an electromagnet, which is responsible for removing ferrous materials and other metallic components that could damage the machines.
– (Gabriel Silveira/)
3) The next step is milling, in which the cane is crushed by crushing rollers. After grinding, 70% of the sugarcane turns into juice, which contains the sugar from which ethanol is extracted. The remaining 30% is bagasse – which can be burned and generate energy for the plant
– (Gabriel Silveira/)
4) The broth here still has up to 1% of solid impurities, such as sand, clay and small pieces of bagasse. That is why it is sieved and goes on to rest in a tank, where, little by little, the impurities are deposited at the bottom – forming a sludge that serves as fertilizer.
5) When well cleaned, the broth is called clarified broth. It is heated to be sterilized and free of the last impurities. It is then taken to the vats, large tanks where it is mixed with a specific yeast
– (Gabriel Silveira/)
6) Such yeast has microorganisms that feed on the sugar in the broth, then releasing carbon dioxide and alcohol. This fermentation stage lasts from 4 to 12 hours, generating a product called fermented wine.
7) The chemical reactions triggered by the yeast also release energy, which warms the fermenting wine. It then needs to be cooled with running water – which circulates around the tanks without coming into direct contact with the wine.
– (Gabriel Silveira/)
8) Fermented wine contains only 10% alcohol – the rest is basically water. So he needs to go to distillation. In several tanks, the wine is heated until it evaporates; then it is condensed and returns to liquid form, but with its various components separated
9) From distillation comes hydrated alcohol, liquid with 96% alcohol. It is he who will be sold at the gas stations. Part of it, however, still undergoes a dehydration process, turning into anhydrous alcohol (more than 99.5% alcohol), which is mixed with gasoline as an additive.
– (Gabriel Silveira/)
10) The two types of ethanol produced, hydrated and anhydrous, are stored in large-volume tanks. There, they wait until they are picked up by tank trucks, which take the ethanol to the distributors to sell the product to the service stations.