Hydraulic Classifier FRAC-Sand Application
The term proppant is a mashup of the words "propping" and "agent" and is the material used to hold open cracks in the rock so that an available path to the well exists. The most common proppant used in the fracturing operation is sand.
A classification of very durable, high-purity quartz sand, with very round grains is referred to as "FRAC sand". The petroleum industry uses it widely due to its crush resistance. It is used in hydraulic fracking to allow the flow of oil, natural gas and natural gas liquids from rock.
A Hydraulic Classifier (also known as density separators) are machines that separate minerals of different specific gravities so a producer can classify them for use (in this case for FRAC sand production). They operate by allowing feed material to enter the top
of the unit, after which water is injected and creates an upward rising current. The result is a zone of suspended solids. Finer materials then flow over a weir at the top of the unit, while coarse solids collect in the lower area. A PID controller maintains the water injection rate and the desired operating density by adjusting the underflow valve to maintain consistent output. The classifier automatically compensates for changes in feed rate.
A Kinetrol USA Midwest Distributor installed a Kinetrol actuator on a Hydraulic Classifier used at a FRAC-sand plant. Previously the customer used an electric actuator which cycled every 2-10 seconds. The electric actuator would burn up after 2 weeks. The Distributor sold them a Kinetrol pneumatic actuator which has worked now continuously for 2 years with no maintenance. The FRAC-sand plant has since purchased 10 more units.