TYPES OF SEPARATORS
Separators are classified by the shape and orientation of the vessel and by the number of fluids to be segregated. In terms of shape and orientation, there are three types of separators, in common use are mainly two, Vertical and Horizontal.
The number of fluids to be segregated is usually, Two or Three.
If there are two fluids, such as gas and liquid, the separator is referred to as a two phase type if three fluids are segregated such as gas, oil and water, the vessel is a three phase type. The number of phases refers to the number of streams that leave the vessel .
The spherical separator provides good gas separation and liquid handling when space is limited. However, when a well stream can contain excess mud or sand, be subject to surging or foamy components, the spherical separator is not economical. In this design the four separator sections are contained within a sphere. The top part of the sphere contains the three sections for gas and liquid separation. The bottom part is the liquid accumulation section.
Figure. Spherical separator
The well stream enters the vessel at the top. Inside the sphere the stream is deflected to the surfaces of the sphere along the walls over a dome covering the mist extractor. As the stream enters the lower portion of the sphere, the gas and liquid vapors begin to rise and pass through the mist extractor. Liquid droplets collect and fall downward. Gas leaves the vessel through a vertical pipe above the mist extractor. Different from other separator designs, the gas outlet is at the bottom.
Liquids accumulate in the bottom of the sphere. Gravity settling causes solids and water to go to the bottom of the vessel. Liquid leaves the vessel near the bottom of the sphere under control of a liquid-level controller.
These types of separators, vertical only, perform a high efficiency demisting. They combine the advantages of the best inlet device, the dish deflector, with the mistmat and a demister pad into one vessel.
Figure – 3 Vertical Separator
In this type the incoming gas initially meets a ‘ dish deflector.` This device reduces the velocity of the inlet stream and changes the direction.
Gas moves up through the mist extraction section where any liquid drops entrained are dropped down. If required an additional demister pad can be provided just before the gas exit to remove very small liquid particles which are not removed in the mist extraction section.
The oil and gas mixture enters through the inlet nozzle and hits an angle baffle (schopentoter) where the direction of flow is changed. Here the heavier liquids fall to the bottom of the tank while the gas and spray liquid rises.
This wet gas passes through the mist extractor (where the remaining small liquid particles are removed) and then along the upper part of the separator to reach the gas outlet.
Figure- 4 Hoizontal Separator
The liquid from which the gas has been removed moves along the bottom of the separator to the oil outlet through a vortex breaker, then the plates act as baffles, which prevent wave formation in the liquid. Level is maintained normally at about 1/3 of the height of the separator. A large liquid surface is thus maintained which facilitate gravity separation.