FSM: Liquid Desander – Introduction to Module M4 (B-FSM042)
Today we start covering material in module M4 “Liquid Desander”. Through the material in this module we will discuss the fundamentals of cyclonic technology, and history and development of the desander for solids removal from liquid only flow (Multiphase Desander is covered in module M5).
The Liquid Desander is a unit process equipment based on cyclonic technology. It is designed to operate in liquid-only flow conditions. The desander is the first step in produced water treatment (PWT) and is used to remove solids/sand prior to oil removal by deoilers or flotation. In reference to the Four Nodes of Separation – this is Node 4 (see blog FSM-006 from August 29, 2017).
Liquid Desander Fundamentals
Process
- First step in produced water treatment
- Remove solids immediately on separator outlet, prior to deoiler and level control valve (LCV)
- Protect PWT equipment (deoiler, flotation, CPI, filter, etc.), protect valves and piping, reduce OIW content, and protect injection system (pumps and wells)
- Can handle small amounts of free gas, but typically not present here
- Can handle bursts, but not large slugs, of solids – not to be used for jetting slurry sand removal
- Large diameter solids (>5 mm) may pose plugging issue
Mechanical
- Vertical vessel with small footprint
- Same design rating/material as production separator
- Simple instrumentation with only differential pressure monitoring required
- Integral accumulator for low pressure (ASME 150#) and secondary/external accumulator needed at higher pressures (ASME 300# or greater)
Outline of Topics to be Covered
- Introduction to Liquid Desander
- Cyclonic Technology
- Hydrocyclone Technology
- Liquid Desander Design & Operation
- Desander Sizing & Selection
- Flooded Core Hydrocyclone & Apex Flux Balancing
- Erosion & Material Selection
- Liquid Desander Operability
- Liquid Desander Mechanical Design
- Flow Sheet Design & Skid Layout
- Liquid Desander Summary
The next article will discuss the fundamentals of Cyclonic Technology.
References
- Ditria, J.C., Hoyack, M.E., “The Separation of Solids and Liquids with Hydrocyclone-Based Technology for Water Treatment and Crude Processing”, paper 28815, SPE Asia Pacific Oil & Gas Conference, Melbourne, Australia, 7-10 November, 1994.
- Hodson, J.E., Childs, G., Palmer, A.J., “The application of specialist hydrocyclones for separation and clean-up of solids in the oil and gas industry”, paper 7590 presented at the 26th Annual OTC, Houston, TX, 2-5 May, 1994.
- Lohne, K., “Separation of Solids from Produced Water Using Hydrocyclone Technology”, Trans IChemE, Vol. 72, Part A, March 1996, pp 169-185.
