The pump industry relies on expertise from a large and varied range of specialists, from experts in particular pump types to those with an intimate understanding of pump reliability, and from researchers who delve into the particulars of pump curves to experts in pump efficiency. To draw upon the wealth of expert knowledge the Australian pump industry has to offer, Pump Industry has established a panel of experts to answer all your pumping questions.
This edition of Ask an Expert will look at the use of progressive cavity pumps in oil and gas applications, as well as special designs to comply with API standards.
Q: What makes progressive cavity pumps suitable for oil and gas applications and where are they most often utilised?
A: Progressive cavity (PC) pumps are positive displacement pumps that handle fluids gently and with minimal shear or turbulence.
They convey abrasive fluids with the highest viscosity and solids content, even with large particles. They can generate high pressure (48 bar and more) and are suitable for high vapour pressure (low NPSH) and multiphase fluids.
In the oil and gas industry, PC pumps are often used to convey sludge or oily water, or in situations where light hydrocarbons raise the vapour pressure to a level where other pump types would cavitate.
A forte of PC pumps is their vertical semi-submersed installation on a drum; open/closed drain drums or flare knock-out drums are a frequent application.
PC manufacturers offer a wide range of pumps for this industry from dosing and open hopper pumps to semi-submersible pumps or package solutions that allow for automatic control.
Q: How do these pumps meet the stringent requirements of American Petroleum Institute (API) 676 standards?
A: Historically PC pumps were primarily utilised in wastewater treatment plants; design and production were often optimised for this market.
In comparison, the requirements of petrochemical applications are more demanding and are based on American standards.
Manufacturers regularly need to customise and upgrade their pumps for use in oil and gas, which dramatically increases costs and lead time.
The most customisation is required for the casing design and shaft seals. Among other criteria, the casing design needs to have fully ASME compliant flanges, higher nozzle loads, flanged casing drain and a design pressure able to achieve higher containment pressure.
Shaft seals also need to be engineered to meet API 682 requirements. To provide project engineers with smooth sailing and purchasers with favourable prices and lead time, some PC manufacturers have designed and produced API 676 conforming pumps. They fulfill the casing and shaft seal requirements while being built with materials suitable for highly corrosive and harsh environments. PC manufactures use their many years of experience to create and produce solutions that help customers save time and money.
About the Author
Peter Vila, Managing Director of SEEPEX Australia, is a progressive cavity pump expert. He has been involved with pumps for over 35 years. Peter spent the first five years repairing pumps and the following 30 years in technical sales, 15 of which have been with SEEPEX progressive cavity pumps.
This Ask And Expert was brought to you by Seepex. For more information visit seepex.com/en
