Etanol a partir do milho: processo produtivo e questões ambientais

Abstract

The global impact generated by the Oil Crisis triggered a series of policies in search of alternative energy sources. In this situation, ethanol, once seen as a byproduct of sugar industries, emerged as a promising substitute for gasoline in Brazil. Established infrastructures, knowledge in industrial alcohol production, and idle capacity were factors that recognized its strategic role and stimulated its production by the National Alcohol Program (Proálcool). Due to favorable climatic conditions, high productivity of sugarcane, and unparalleled efficiency of the process, the country became a pioneer and assumed a prominent role as an ethanol producer. However, the low durability of sugarcane after harvesting and the long offseason pose challenges and idle capacity. In the Midwest region, the country's main grain producer, difficulties related to high production, storage, transportation, and instability in corn prices also emerged. Faced with these obstacles in both sectors, the first corn ethanol plant in Brazil appeared, of the Flex type, taking advantage of the surplus during idle periods of sugarcane ethanol production. Subsequently, plants of the Full type emerged, entirely dedicated to using corn as a raw material, and Full Flex, which use both sources simultaneously. The use of corn brings several advantages due to multiple harvests throughout the year, ensuring a constant supply to the plant and market diversification with byproducts such as oil and distillery grains, primarily used in animal nutrition. Ethanol production shares common concepts between sugarcane and corn but differs according to the carbohydrate source, requiring adaptations such as drying, milling, cooking, and liquefaction to ensure fermentation, as well as altering operating conditions. The relatively recent implementation of this new industrial model raises questions about environmental impacts, whether positive or negative, and how it can contribute to reducing the carbon footprint. This study aims to analyze the technologies and environmental issues involved in the production process of obtaining anhydrous ethanol from corn.