From the point of energy efficiency a very simple effect also has to be considered:
Particle burnout takes some time.A particle igniting earlier under given ambient conditions will burnout earlier,which means that heat release profile in a rotary kiln will have a tendency to lower back-end temperature influences the heat transfer characteristics in the suspension preheater aiming at reduced thermal losses with the exhaust gas finally resulting in a higher thermal efficiency of the complete kiln system.

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