Describe the process of spontaneous combustion in a biomass fuel pile and its prevention.

Spontaneous combustion in a biomass fuel pile is a process where the material self-heats to its ignition temperature without an external heat source. It starts with biological activity: microorganisms like bacteria and fungi decompose the organic matter, generating heat as a byproduct of their metabolism. This is especially prevalent when the biomass has a high moisture content because moisture provides a favorable environment for microbial growth. As the temperature rises within the pile, chemical oxidation reactions begin to occur. These reactions involve the biomass material reacting with oxygen in the air, further releasing heat. If the rate of heat generation exceeds the rate of heat dissipation, the temperature continues to climb. Poor ventilation within the pile impedes heat dissipation, allowing the temperature to escalate. If the temperature reaches the ignition point of the biomass, combustion occurs. Prevention of spontaneous combustion involves several strategies. Managing moisture content is essential, as drier biomass inhibits microbial activity. Proper ventilation allows heat to escape, preventing temperature buildup; this can be achieved through pile design and turning the pile. Compaction reduces air spaces, limiting oxygen available for oxidation. Temperature monitoring helps detect early signs of heating; thermocouples inserted into the pile can provide valuable data. A first-in, first-out (FIFO) inventory system ensures that older material is used before it has a chance to self-heat. Firebreaks can also limit the spread of any combustion events.