The Gravity Separator makes a highly sensitive dry separation on the basis of one of three particle characteristics: density, size or shape. When size and shape are controlled within certain limits, the gravity separator is unmatched in its ability to separate a complex mixture by density. The relative size and shape of each component of the mixture also bear on the efficiency of the separation. Wide variations in these material characteristics can dramatically affect the separation results.
Where a wide range of particle size is present, screening may be required to segregate materials into manageable size ranges prior to separation. Where significant variations in shape are found to be detrimental to separation efficiency, size reduction may be added to the process. These factors become more important as the densities of the material to be separated become closer.
Classified by their geometrical configurations as vertical or horizontal separators, they function as two-phase separators if they separate gas from a total liquid stream, and three-phase separators if they separate gas from liquid and liquid into crude oil and water phases.
Gravity separators can be categorized according to their operating pressure as shown in the table below:
Pressure kPa PSI
Low 69 to 1241 10 to 180
Medium 1586 to 4826 230 to 700
High 6722 to 10342 975 to 1500
1. Gas/liquid separation section with an inlet diverter to remove the bulk of the liquid from the gas. In most designs, the inlet diverter contains a downcomer that directs the liquid flow below the oil/water interface
2. Gravity-settling section, this section allows a retention time so that proper settling may take place.
3. Mist extractor at the gas outlet to capture entrained droplets or those too small to settle by gravity.
3. Pressure and liquid-level controls.