Biological Evidence 2024, Vol.14, No.1, 1-10 http://bioscipublisher.com/index.php/be 3 corn requires additional cooking and enzyme application. Furthermore, the energy required for sugar conversion is about half that of corn, and the energy produced by sugarcane is sufficient to cover the conversion energy. A report from the U.S. Department of Agriculture in 2006 found that, at market ethanol prices, converting sugarcane, sugar beets, and molasses into ethanol would be profitable. By mid-2009, the first three sugarcane-based ethanol production facilities were operational in Louisiana. Other materials such as cheese whey, barley, potato waste, beverage waste, brewery, and distillery waste can also be used as raw materials for ethanol fuel, but their scale is significantly smaller compared to corn and sugarcane ethanol, as facilities using these materials can produce only 3 to 5 million gallons (11×103 to 19×103 cubic meters) annually. 1.2 Production process Ethanol fuel, as a renewable energy source, involves several processes in its production, including raw material handling, fermentation, separation, additives, storage, and distribution. It encompasses critical steps such as biomass conversion, fermentation, and distillation, making it an environmentally friendly and sustainable alternative energy source. In the future, with continuous technological innovation and optimization, the production process of ethanol fuel will further enhance efficiency and reduce costs, contributing more to the development of sustainable energy. The primary raw materials for ethanol fuel are derived from biomass, including various plant materials such as corn, wheat, sugarcane, and wood. Before the production process begins, biomass needs to be collected and pretreated. The collection process involves crop cultivation and harvesting, as well as the logging and processing of wood. Pretreatment includes activities like chopping and grinding biomass to increase its surface area, facilitating subsequent enzyme action and saccharification reactions. Biomass conversion is one of the core steps in ethanol fuel production. During this stage, pre-treated biomass is heated and processed to convert polysaccharides such as starch and cellulose into fermentable sugars. Saccharification reactions are achieved by adding enzymes or other catalysts to convert starch into glucose and cellulose into xylose and glucose, providing raw materials for subsequent fermentation. The resulting sugar solution is introduced into a fermentation tank, where, under the action of microorganisms, sugars like glucose and xylose are converted into ethanol and carbon dioxide. Common fermentation microorganisms include brewer's yeast (Saccharomyces cerevisiae) and Escherichia coli. The fermentation process typically requires controlling parameters such as temperature and pH to ensure optimal fermentation outcomes. After fermentation, ethanol forms a mixture with fermentation by-products, and separation of ethanol is achieved through distillation and purification. Ethanol has a lower boiling point, allowing it to be extracted from the mixture through distillation. This process also involves further purification to remove impurities, ensuring ethanol's purity meets fuel standards. Dehydration is a critical step in ethanol fuel production because ethanol and water form an azeotrope, and a series of separation and dehydration techniques are necessary to remove water from ethanol to obtain high-purity ethanol fuel. Common dehydration methods include molecular sieve adsorption and steam dehydration. Once high-purity ethanol is obtained, it needs special additives to enhance the stability and longevity of ethanol fuel. These additives include preservatives, antioxidants, and detergents. Following dehydration and purification, the obtained ethanol fuel meets fuel standards and can be used in transportation, industrial production, and other applications. Ethanol fuel is typically stored in sealed containers to prevent contamination by water and impurities. Ethanol fuel distribution commonly involves pipeline transport or tanker truck delivery to terminal sales points such as gas stations. The final product of ethanol fuel can be of different blends, such as E10 (containing 10% ethanol), E85 (containing 85% ethanol), and so on. Its application is continually expanding, making a positive contribution to achieving clean energy and sustainable development.
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