乙醇生物燃料生产流程How a biofuel called ethanol is produced

The diagram illustrates how ethanol, a biofuel, is produced in a continuous cycle that connects plant growth, industrial processing, fuel use, and carbon dioxide emissions. Overall, the cycle begins with plants absorbing sunlight and carbon dioxide, then moves through several stages of processing and fermentation to create ethanol, which is used in vehicles. The carbon dioxide released during combustion is recaptured by plants, completing the circle. In detail, plants and trees grow by harnessing energy from sunlight and carbon dioxide (CO₂). Once harvested, this biomass undergoes pre-processing to break it down into cellulose. The cellulose is then chemically treated to form simple sugars. After that, microbes are added to these sugars, triggering a fermentation process that yields ethanol. Finally, the ethanol is used as a fuel in cars, trucks, and aeroplanes. When burned, it emits carbon dioxide, which is released into the atmosphere. This CO₂ is then taken up again by new plant growth, which feeds into the start of the cycle, showing a sustainable, closed-loop system.