Self-flushing anti-cavitation trim eliminates maintenance outages, while decreasing noise and vibration and eliminating cavitation damage.
When it comes to midstream pipeline applications, end users need a robust anti-cavitation solution that is not prone to clogging. The pressure letdown valves at a Midwest NA petroleum pipeline terminal required routine shutdowns every three months for cleaning and maintenance. Performing this maintenance required anywhere from four to more than 24 hours and resulted in tremendous amounts of lost production.
When our representatives visited the installation they discovered a non-Neles solution comprised of two 20" globe valves being used to stage the pressure drop from approximately 500 psi to 100 psi before delivering the product downstream in the terminal. The pressure differential across the valves generated excessive noise and vibration, which resulted in damage to the valve.
Vibration damaging the valve was not the only problem, though. To prevent clogging of the valve’s anti-cavitation trim, a large strainer was placed upstream of the valves to remove debris from various grades of crude before it could clog the valve. The terminal operators explained that after a few months the strainer itself would become clogged. It would have to be removed and cleaned along with the valve’s anti-cavitation trim. This required hiring a crane, a maintenance crew, and hours of lost production while the maintenance was being performed. Maintenance and lost productivity cost the pipeline operator USD 150,000 to USD 200,000 with each occurrence.
Finding the perfect solution with the Q-Ball technology
The problems experienced with the letdown valve were something our representatives had seen many times before, and they had an ideal solution. After presentations with corporate engineering, the pipeline company elected to replace the two 20" non-Neles globe valves with a single, Neles 16" rotary ball valve with patented Q-Ball™ technology. The valve was sized in our valve sizing software, Nelprof, to confirm its ability to accommodate higher flow rates anticipated in the future.
Thousands of Neles rotary valves equipped with the Q-Ball design have been installed in liquid applications involving high-viscosity fluids containing impurities. Crude oil is a prime example. The rotation of the Q-Ball attenuator, attached to the valve closure element, is the key to the unique Q-Ball properties not found in other noise/cavitation trim valves. Due to this variable attenuation, Q-Ball valves optimize noise attenuation, pass impurities, provide very high rangeability and help increase uptime for our customers.
The terminal yard installed the Neles letdown valve with Q-Ball in December 2010. In over a decade, the strainers have been removed, noise and vibration continue to no longer be an issue, and the valve has never clogged. The results have been so positive, they have standardized Q-Ball technology for the pressure letdown application.
The Q-Ball solution can be applied to many applications with this same scenario. Fixed resistors that are in applications with debris will inevitably clog, leaving the customer in a difficult situation of not being able to pass their required flow, the valve can potentially seize, and, in a worst-case scenario, they have to immediately shut down their process to fix the issue. Q-Ball’s self-flushing technology sets the industry standard for reliability and uptime in dirty media.
Text: Steven Hocurscak. For additional information on this content, please contact joonas.korhonen@valmet.com
The text has been updated in April 2022, due to the company name change to Valmet.
