Emerson’s Justin Lannin and Vinson Process Controls’ Mike Stinn teamed up to present, Hex & The City: Ponca City Refinery Reduces Maintenance with Fisher Cavitrol Hex, at the 2022 Emerson Exchange conference. Here is their session’s abstract:
Phillips 66’s (P66) Ponca City Refinery, in Ponca City Oklahoma produces a full range of products and has a large blending unit where finished products are made. A severe service application in the gasoline blending process was causing accelerated damage to nine rotary valves. As a result, these nine valves became unreliable and had to receive frequent maintenance, driving up parts and labor costs. With the application of additive manufacturing, Emerson developed a new rotary valve trim that could handle the severe service conditions like those seen at P66 Ponca City.
Mike started with an overview of this refinery. It’s a 230MBPD refinery built in the 1910s. The blender unit is a low-pressure unit with a pressure drop from 100 to 10psig. Cavitation is an issue across the pressure reducing control valves. The pressure through the valve drop where the liquid transitions to gas below its vapor pressure. This is highly damaging to the valve stem and seat, or ball in ball valves.
Justin provided an overview of valve sizing for applications with cavitation. To mitigate and eliminate cavitation three strategies include resistance, isolation and elimination. Isolation is breaking up the flow into separate streams via a Cavitrol valve cage. Elimination is taking the pressure down in steps where no steps drop the pressure below the fluid’s vapor pressure. The Cavitrol Hex was possible to create with the advent of additive manufacturing—a 3D printing technology using laser powder bed fusion.
It breaks up the flow in smaller streams for Veeball valves and can be used in dirty service applications. Different cavitation solutions include Fisher Veeball + Rotary Attenuator, Veeball + Cavitrol Hex, and ET + Cav II 1-Stage NP56 & NP58.
Mike shared the Ponca City refinery case study. They were having serious cavitation, vibration and noise issues causing the spool pieces to be constantly replaced. When they added the Cavitrol Hex they have not had any problems or needed to replace these spool pieces over three years. Since that success they have added the Cavitrol Hex to other valves in the refinery experiencing cavitation. Since these replacements in 2019 they have experienced no downtime or cavitation and vibration issues.
Visit the Cavitrol Hex page on Emerson.com for more information on how this technology can reduce cavitation and vibration issues.