Silo sizing and mixing to improve outgoing quality of fertilizer

Because of prevailing large variability in the process, mean level of the nutrients is set at higher value to meet stringent specification. Large variability has resulted in reprocessing leading to loss in saleable production, and increased cost for reprocessing. Higher process average (mean level) gives rise to free-give-away of costly nutrients to the customers. In this article, we determine the required size of silo (primarily for storage) and study suitable stacking and mixing methodology to reduce variability in outgoing product. As a result, it is expected that reprocessing would be eliminated completely, and process average could be reduced. The consequential annual benefit is worked out as Rs. 50 million on direct savings.