What process can effectively extend the lifespan of diesel fuel during storage?

Fuel polishing is the correct process that can effectively extend the lifespan of diesel fuel during storage. This method involves circulating the fuel through a polishing system that removes contaminants such as water, sediment, and microbial growth, which can degrade the fuel quality over time. By keeping the fuel clean and free of impurities, fuel polishing helps to maintain the fuel's integrity and ensures it remains viable for use over an extended period.

In contrast, the addition of antifreeze is primarily used to prevent diesel fuel from gelling in cold temperatures but does not directly enhance the overall quality or longevity of the fuel during storage. Reducing the storage temperature might help slow down the degradation process but is not a definitive solution for maintaining fuel quality. Similarly, using gravel filters can capture larger particles but is not as effective as a comprehensive fuel polishing system, which addresses multiple types of contaminants and maintains the fuel's optimal condition.