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New design features enhance separation performance

The Shell Schoepentoeter is a vane-type inlet device for feeding high momentum gas-liquid mixtures into separators or distillation columns. The Schoepentoeter has two main functions: separating the liquid from the vapor and evenly distributing the vapor in the gas compartment of the vessel.

While Schoepentoeters have been recognized as the primary choice of radial inlet device in many separator vessels, performance in distillation columns has been challenged by proponents of the tangential vapor horn style inlet device, particularly at high column load factors. The improved design of the next generation Schoepentoeter Plus resolves these concerns, optimizing separation efficiency without compromising hydraulic capacity.

How a Schoepentoeter Works
The Schoepentoeter divides the mixed phase feed stream into a series of lateral flowing streams. The vanes dissipate the kinetic energy of the streams for a smooth entrance into the vessel, and also provide centrifugal acceleration to promote separation of the liquid from the vapor.

Sulzer, in partnership with Shell Global Solutions, studied the Schoepentoeter design and modified key features to accommodate improved de-entrainment performance. Lab test results for the Schoepentoeter Plus showed a similarly high vapor distribution quality as with the conventional design, but significantly better vapor / liquid separation, particularly at the high column load factors.

Improvements in the Schoepentoeter Design
In the updated Schoepentoeter Plus design, new catching rims have been installed at the exit of each vane to convey the captured liquid separately down to the bottom section of the tower, avoiding contact with the ascending vapor. This new feature reduces liquid entrainment by over 60% when compared to the conventional design, without any significant increase in pressure drop.

Case Study: Commercial Separator Application
Excessive aqueous-phase liquid carryover was experienced at the inlet separator of an existing gas processing facility, resulting in chloride precipitates fouling downstream compressor blades and costing critical compressor performance. Sulzer replaced the current equipment with a Shell Schoepentoeter Plus design, reducing entrainment from 4.5% to less than 1.5%, essentially tripling the compressor run length.

Conclusions
The new design features of the Schoepentoeter Plus inlet vane device reduce entrainment down to just 30% of the conventional Schoepentoeter, providing the best possible performance of any radial inlet feed device. Schoepentoeter Plus installation requires less welding and down time compared to other high performance feed devices, making it ideal for revamp applications.

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