## FSM: Liquid Desander – Sizing and Selection: Application Steps (B-FSM054)

We now start the discussion on sizing and selection of a desander for separation duty. This takes all the theory we have previously detailed and adds calculation steps to properly size a desander for your application.

There are quite a few good sizing routines available. I recommend starting with Plitt (see references). Please keep in mind that he is sizing a hydrocyclone, not a desander, so the appropriate modifications must be made to account for no flow split. Svarovsky also publishes quite a few sizing equations, which are valid for various applications and geometries.

The routine I have outlined below was published in 2001 (see Rawlins and Wang reference). It is the commercial routine I’ve used since my grad school days. In this post I am just detailing the main application steps. Subsequent posts will provide the calculation details – but I need to give an outline first.

**Application Steps for Desander Selection **

- Select the size of desander (insert or liner) geometry for separation duty

- Gives appropriate separation size (D98)
- Gives required total solids recovery (%)
- Meets allowable pressure drop (ΔP)

- Select appropriate number of operating units for flow and turndown

- Insert style: number of vessels in parallel operation
- Liner style: number of liners (design, high, and low flow) in the vessel

- Select appropriate mechanical design rating and materials of construction

- Vessel diameter determines insert diameter or quantity of liners
- Appropriate vessel mechanical design rating (i.e. ASME) suitable for design pressure and temperature
- Vessel materials of construction for corrosion control
- Insert/liner materials of construction for erosion control

The next article discusses desander geometry for separation duty.

**References**

- Plitt, L.R., “A mathematical model of the hydrocyclone classifier”, CIM Bulletin, December, 1976, pp. 115-123.
- Rawlins, C.H., and Wang, I. I., “Design and Installation of a Sand Separation and Handling System for a Gulf of Mexico Oil Production Facility,” SPE Production and Facilities, paper 72999, Vol. 16, No. 3, 2001, pp. 134-140.
- Svarovsky, L., “Hydrocyclones”, Technomics Publishing Co. Inc., Lancaster, PA, 1984.