HOW TO INCREASE FRAC SAND PRODUCT YIELD
There is a direct correlation between wasted product – which sometimes could be as high as 50% — and the process system efficiency at a frac sand manufacturing plant. The solution to minimize waste and increase profits lies in the optimization of plant product yield. Product yield is key to the economics of a plant’s operation. In a frac sand operation, the product yield is the relation between tons of sand grain liberated for sale and the actual tons of material mined. An analysis of the core sample will determine the product quantity per ton of material mined. The product yield in relation with the product in the mine should be in the neighborhood of 75%. In order to improve frac sand product yield, the following is a recommended course of action: 1. Verify that the main crusher is adequately sized for the vertical shaft impactors (VSI). This equipment tends to choke easily due to limitations at the feed point. The rock size exiting the crusher is important for the proper operation of the VSI. 2. VSIs should be properly sized for the amount of material feed. A small VSI will not de-cluster the frac sand completely, leaving sand in clusters. On the other hand, a large VSI will shatter the sand, damaging the sand particle shape. The correct size of a VSI should be determined by working closely with the VSI equipment supplier and running sample tests.
Producers may not realize how much product is being wasted by poor equipment selection. A particle size distribution test on the waste material is a good indicator of how much good product is being wasted.
The main contributor to this article was Pompeyo D. Ríos, Senior Mechanical Consultant, at PEC Consulting Group, St. Louis, Missouri.
