The main components of a multiphase desander system are listed below. The header graphic shows the configuration of the technology for wellhead (upstream of the choke) use, however the main components are the same downstream of the choke when used as a wellstream desander.

Multiphase Desander Vessel

• Contains pressure for separation but not subject to erosion
• Designed to ASME (150# to 1500#) for wellstream use or API-6A (5/10/15 K) for wellhead use
• API design allows for full shut-in pressure (no PSV required)
• NACE MR0175 compliant
• O.C.: Carbon steel (forged 4130 for API)
• Small hold-up volume for sand

Cyclone Insert

• Performs separation duty and contains erosion
• Interchangeable size in standard vessel (4”-10”) with up to 20” diameter inserts
• Standard: 410 stainless steel with surface hardening
• Normally 1-2 year life

Isolation Valves (DBB)

• Double block and bleed valve set to isolate accumulator
• Slab gate type recommended
• Hard facing on trim

Accumulator

• Containment volume for sand – recommend 12-24 hour hold-up
• Designed to full shut-in pressure (API use)
• Same M.O.C. as multiphase desander vessel

The next article lists key technical references for multiphase desanding.

References

1. Rawlins, C.H. 2017. “Separating Solids First – Design and Operation of the Multiphase Desander”, paper 185658-MS presented at the SPE Western Regional Meeting, Bakersfield, CA, 23-27 April.