A client near South Africa had been utilizing Titanium butterfly valves to vent steam from their flash vessels. Due to the vapour also containing acids and fine particulates, the butterfly valves were quickly compromised and removed from service after 1 month. If the erosion damage was determined unrepairable (see Fig 1), a new butterfly valve was installed in its place.
The valve’s butterfly disc would also accelerate abrasive fluid towards the downstream pipe walls. Over time, this caused the client’s Titanium piping to erode, eventually resulting in a breach (see Fig 2). The costs associated with labour, replacement valves, downtime and lost production were significant.
20" titanium slurryflo control valves
With an analysis of the process conditions and modulating history, SAF's engineering team developed a unique ‘dual purpose’ trim (see Fig 3). As the gate opens, it exposes two small ceramic orifices to vent steam (see Fig 4). Once the flash vessel has been vented, the gate can be retracted further if additional flow is required (see Fig 5). Note that flow is centered within the pipe in both scenarios.
Upon replacing their Titanium butterfly valves with SlurryFlo control valves, the client quickly realized a return on investment. During the first inspection (1 month post installation), the maintenance team observed minimal erosion on the wear components. As the downstream piping also remained in excellent condition, it was decided to operate the valves for several months between inspections. After 12 months of continuous service, the valve trims are replaced and the valves are reinstalled.