ID is key. The internal vessel diameter, aka “ID” is critically important. Too small or too big and the centrifugal and centripetal forces that enable the separation inside a cyclonic sand trap break down and capture efficiency plummets. The most efficient ID is between 14” and 15”.
The smoother the better. The smoother the interior surface of the cyclonic canister, the better it works. Stainless steel provides an exceptionally smooth surface and has the added benefit that it is extremely hard. This means a cyclonic canister made from stainless will last far longer than one made from carbon steel (even hardened carbon steel).
Dump often and don’t pay for what you don’t need. Captured sand is stored in bottom portion of a cyclonic sand trap. Sand is dumped (“blown down”) frequently so sand storage does not need to be over-sized. Every 3 – 5 gallons of sand accumulation is enough to warrant a blow off. If too much sand accumulates, sand can become compacted and plug the sand dump. When this happens it forces the well to be shut in and a tedious cleaning of the sand trap. That’s why experienced flowback and testing operators dump often. Extra vessel length on a sand trap just adds weight and cost. Each foot of 5 inch thick vessel adds a thousand pounds in weight and much more than a thousand dollars in cost.
Flanges determine temperature. The maximum temperature at which a vessel can be safely operated is typically defined by the flanges used when the vessel was built. Unfortunately, as temperature goes up, flanges cost a lot more. To keep costs down, many fabricators use cheap flanges that have a max temp rating of around 130 degrees Fahrenheit (54 C). By code, this limits the max operating temperature even though the vessel steel is rated for a much higher temperature at rated pressure.