More than 1000 gas/liquid separators are successfully operated worldwide with Shell’s separation technology.
Shell proprietary high-capacity gas/liquid separators, such as Shell SMS, SVS, SMSM and SMMSM separators, combine the best features of the separation products from Sulzer and Shell’s portfolio. Shell gas/liquid separators combine Swirldeck, KnitMesh, and Schoepentoeter separation technologies in a single vertical vessel drum.
The selection of separation technologies is a function of the dispersed liquid phase concentration, droplet size, and the required separation efficiency.
Their typical application is for separation of liquid/gas or three-phase liquid/liquid/gas mixtures, when high capacity and high separation efficiency is required.
SMS(M) technology is the lowest weight and volume solution for phase separation offshore and onshore. It provides up to 2.5 times more capacity compared to a conventional KnitMesh mist eliminator without vessel replacement.
Description of Shell Swirltube™ systems
Shell SMS, SMSM and SMMSM gas/liquid separators are named after the configuration of the different internals used for each type of separator:
Different configurations of Shell gas/liquid separators
- Schoepentoeter (S) - used as feed inlet device for vapor distribution with bulk liquid removal
- KnitMesh (M) - which acts as coalescer and separator, depending on the gas flow rate
- Double Primary KnitMesh (MM) - specially developed for applications with two immiscible liquid phases in the feed to the separators (such as glycol condensate in dew-point separators)
- Swirldeck (S) - comprising multiple Swirltubes. A second KnitMesh (M) is used downstream of the Swirldeck in SMSM gas/liquid separators for demisting secondary gas. In fouling or waxy service, the KnitMesh can be replaced by a Sulzer Mellachevron vane pack (SVS systems).
- A second KnitMesh (M) is used downstream of the Swirldeck in SMSM gas/liquid separators for demisting secondary gas. In fouling or waxy service, the KnitMesh can be replaced by a Sulzer Mellachevron vane pack (SVS systems).
Principle of a Shell Swirltube
The Shell Swirltube™ is, in essence, a stainless steel tube with a swirler at the inlet and longitudinal slits in the tube wall. Liquid is separated by impaction of droplets and on the tube wall by the centrifugal forces induced by the swirling gas flow.
Re-entrainment of this liquid is prevented by draining the film via the slits to the liquid collection chamber outside the tube.
To ensure the proper functioning of the Swirltube™ it is essential that some gas is also bled through these slits. This gas leaves the liquid collection chamber via the secondary outlets at the top of the Swirldeck assembly.
Performance can be improved by using a secondary KnitMesh mist eliminator to separate entrainment from the gas leaving the secondary outlets. The main fraction of the gas leaves the Swirltube via the primary gas outlet at the top.
Drain pipes guide the liquid, collected in the space between the tubes and on the upper cover of the Swirldeck, to below the liquid level.
Scaling-up of a separator equipped with a Swirldeck is done simply by increasing the number of Swirltubes proportional to the gas flow in the separator.
Recommended use for the advanced Shell Swirltube Light™:
- Comparable performance to vane packs but with higher liquid handling capacity
- Operation possible at higher pressures than vane packs
- Due to compact size suitable for offshore industry or in general for high-pressure conditions
- For debottlenecking of existing separators
- For high turndowns (up to factor 10)
- Advantageous for slightly fouling service and may be used where double-pocket vanes or wire mesh mist eliminators may become plugged