Aeration Control
Air is blown into the heap via a series of parallel stringer pipes from low-pressure blowers. The stringers are designed to provide the best possible distribution of air throughout the heap. Due to the variation in oxidation rates throughout the lifecycle of a heap, a large band of flow rates must be employed to ensure heat retention for optimum bacterial activity. Aeration rates close to the maximum flow rate can be controlled by damping the blower inlet. Aeration rates significantly lower than the normal operating rates will cause uneven air distribution in the air stringers, and therefore unequal aeration and temperature profiles in the heap. In the low aeration ranges, airflow is controlled by pulsing air into the system. In a large heap system this is accomplished by switching the heap panel aeration lines on and off via a timer, or via PLC control.