The proper design and use of separator internals can either reduce the size of a separator or greatly improve the separation performance. Sometimes it can do both. VME’s proprietary custom-designed internals greatly improved the performance of the high-pressure separators (HPPT) at Saudi Aramco’s Uthmaiyah GOSP-8 (Delevan, D. and Wilson, T).1 Read the full report here.
Multi-Vane Inlet Devices
A multi-vane inlet, or Schoepentoeter style inlet device, is used when momentum values of the process flow reach a level where the use of a half-pipe inlet device is not advisable.
The multi-vane inlet device consists of a varying number of radially curved vanes which redirect the process flow outward and down. This is considered the primary phase of separation because the majority of bulk gas disengagement occurs as the fluid is sliced and separated by the vane blades, gently reducing the inlet momentum. The lower momentum flow minimizes the foaming tendency of the incoming fluid. An added benefit of multi-vane inlet devices is that they can be modified for either horizontal or vertical vessels to bring functionality across a wide range of operating conditions.
Cyclonic Inlet Devices
The cyclonic inlet device is the choice of most operators because of its compact and highly efficient design. Cyclonic inlet devices are efficient for bulk phase separation, maximizing gas disengagement without portending to foam generation. Used in two-phase and three-phase separators, the cyclonic inlet device redirects the flow to a series of cyclone tubes of varying dimensions based upon the characteristics of the process flow.
The centrifugal forces generated in the device enhance primary phase separation. The centrifugal force causes the liquids to spiral to the outside of the tubes where the heavier liquid phase is forced downward and out of the bottom. The vortex created in the cyclone tubes prevents gas carry-under and re-entrainment while channeling the gas phase to the center and out of the top of the tube. The cyclonic inlet device has a narrower operating range and should be used in applications with less variation in the process flow.
Anti-Motion, Flow Conditioning and Laminar Flow Stabilizing Baffles
Unwanted introductions of motion are prevalent in many offshore applications. These sporadic introductions of motion can lead to non-uniform flow patterns which can affect residence time and hinder adequate separation. VME’s anti-motion baffles, Lami-Flow PacksTM and flow-conditioning baffles serve to minimize the effect of unwanted motions to ensure optimal separation conditions.
As with all VME internals, our anti-motion and flow conditioning baffles are designed on a case-by-case basis and are backed by CFD flow and motion studies. Lami-Flow PacksTM are used in applications where high fluid loading exists in an under-sized horizontal vessel. The packs are used to mitigate the effects of horizontal turbulent flow.
Liquid-Liquid Coalescer Packs
Gravity settling serves as the driving force of liquid-liquid separation. The use of liquid-liquid coalescer packs can greatly accelerate this separation. As small droplets coalesce into larger droplets, separation of the continuous and dispersed phase increases. VME’s corrugated plate coalescer packs (CPC PacksTM) and Dixon Plate Coalescer packs serve to decrease the required retention time needed to achieve liquid-liquid separation while achieving customer specifications.
By channeling the flow, coalescer packs increase the prevalence of droplet collision and coalescence. Because larger droplets require less retention time within the vessel, we are able to reduce the vessel size, thereby reducing the overall footprint of the entire separator package. Operating results from field studies show that CPC Packs can remove up to 15 times the amount of water of a vessel without coalescer packs (Delevan, 1995) while reducing demulsifier consumption by 40 to 60%.
Sand Jetting Systems
Depending on the characteristics of the process flow, sand accumulation may become an issue during the primary phases of separation. Excess sand accumulation can lead to corrosion and clogging of piping and other equipment located downstream.
VME’s sand jetting systems are designed to utilize pressurized water to fluidize the sand into a liquid slurry. The slurry is then drained through multiple sand outlet nozzles located along the length of the vessel.
Foam Breakers (Defoamers)
Foaming tendencies of certain process flow conditions can inhibit adequate separation and can exacerbate liquid carryover. Furthermore, foam can cause errors in detecting the liquid-gas interface in two- and three-phase separators. Chemical solutions to combat these foaming tendencies can require a multitude of different chemicals that can become extremely expensive.
VME’s proprietary foam breaking design Foam EliminatorTM employs mechanical means to rupture the foam bubble and improve the separator performance. Our proprietary pocketed design induces mechanical stress on the film around the foam bubbles. As the foam enters the packs, disruption of the surface tension equilibrium causes larger bubbles to rupture immediately. As the remaining bubbles are forced through the pack, smaller bubbles stretch and rupture. Finally, any remaining bubbles expand and rupture as they exit the packs.
Vane Mist Eliminators and Mesh Pads
In oil and gas separation, it is crucial to mitigate the amount of entrained liquids in the gas stream to prevent liquid carryover to the compressor. VME’s proprietary mist eliminating outlet devices allow for the removal of up to 99% of small liquid droplets. Through the impingement process, our vane and mesh mist eliminating devices ensure efficient and adequate removal of liquid particles from the gas stream by utilizing the inertial differences of the gas and liquid molecules.
Because all VME internals are custom-designed to our customer’s individual process characteristics, we are able to accommodate a wide range of services from clean to heavily fouled environments. Our versatility is enhanced further by our catalog of proprietary pocketless, single- and double-pocketed vane pack designs.
Axial Cyclonic Demisting Decks
VME offers demisting capabilities through the use of axial cyclonic demisting decks. These cyclones are being utilized more frequently throughout the oil and gas marketplace because of their efficiency in high-pressure environments and in high gas/liquid loading cases.
Because of their efficient process, axial cyclonic demisting decks allow us to decrease the size our process packages for a savings of both cost and footprint size. Similar to cyclonic inlet devices, centrifugal forces and utilization of density differentials allow high levels of liquid/gas separation in a range of applications. These cyclonic demisting decks also boast foam-breaking abilities and non-fouling properties.