Progressive Cavity Pumps for Challenging Oil & Gas Applications

In the past, centrifugal pumps were the norm for many oil and gas applications. But such pumps require relatively high net positive suction head available (NPSHa) levels and are often susceptible to cavitation. Operators at two different types of oil and gas facilities have found progressive cavity pumps to be an efficient alternative solution, offering better suction capabilities at lower net positive suction head required (NPSHr) levels than centrifugal pumps. Progressive cavity pumps are also an energy efficient option, resulting in operational cost savings. To get more news about progressive cavity pump rotor, you can visit brysonpump.com official website.

Engineers for a pipeline company that transports lighter hydrocarbon liquids produced in Canada were designing a high-pressure flare system for a bulk storage terminal project. They needed a pump solution to empty the flare knockout drum (FKOD) vessel, an integral part of the flare system.

FKODs are essential components of industrial pressure relief systems at gas and petroleum sites and play a crucial role in safe operations. Also called vapor liquid separators or knockout pots, liquid knockout drums capture and remove accumulated liquids that condense during the ordinary expulsion of relief gases. Flare systems generally require an FKOD to separate liquid from gas and to hold the maximum amount of liquid that can be relieved during an emergency situation or maintenance activities.

Knockout drums are typically located on the main flare line upstream of the flare stack. These vessels are either above-grade or below-grade and typically operate at vapor pressures of up to 103 kilo-pascals-absolute (kPaA). There is often not a lot of energy to get the fluid into the pump suction. In this project, the fluid was light oil/condensates (C5+) with a low viscosity of 0.2 to 0.7 centipoise (cP), so the engineer sought pump options other than typical centrifugal pumps, which require higher NPSHa levels and can be susceptible to cavitation. The client also required a pump that can achieve high discharge pressure.
The project engineers were trying to make the FKOD pump more efficient because they wanted to operate within the specified best efficiency point (BEP). They eventually selected a vertically mounted progressive cavity pump, which provides better suction capabilities at lower NPSHr levels than some other pumps. Progressive cavity pumps can handle low (or high) viscosities; they can operate more efficiently with less wasted energy.

Progressive cavity pumps work well for above-grade and below-grade sump tanks. Semi-immersing the pump in the tank enabled operators to drain the tank down to only a few inches of liquid at the bottom.