Typically urea prill or granules production is measured by belt scale meters as they flow into or out of the warehouse. It is common knowledge that these flow meters contain a degree of error. Over time, the calculated inventory will differ from real inventory significantly. In one case, Inlibra Software Solutions Corporation found that without correction, the running inventory calculated solely from meters would have a 20% error by the end of one year.

To avoid cumulative error, commonly urea producers engage topographical surveyors to measure the shape of the stockpile mound with surveying equipment such as theodolites. Topographical surveys are not an ideal solution as they are costly and can only be done infrequently (perhaps once a month).

The Stockpile Tracker provides continuously information how much urea is in the warehouse, so that urea producers know at any particular instant in time how much inventory they have on hand. The Stockpile Tracker further acts as a double-check on both the meters and on the topographer’s results.

Using real-time measurements pertaining to both additions and removals, the Stockpile Tracker models the volume and mass of a prilled or granulated urea stockpile over time, providing up to date inventory via intranet web displays and storing the data in a database from which it can be queried for reports.

The Stockpile Tracker is able to model the changes in stockpile shape because the shape only changes at two places:
– where there are additions to the stockpile, usually poured onto the pile from above
– where there are removals from the stockpile, usually scraped onto a conveyor belt by scraper arms
All that is required is sufficient measurement at those two critical places.

The Stockpile Tracker has been successfully deployed in the largest urea warehouse in the western
Hemisphere.

2010_11_Maschmeyer_Inlibra_UreaKnowHow.com_Stockpile_Tracker.pdf