Separators, Dividers, and Settlers

Separators appear among the most indispensable elements of any technological scheme of on-site preparation of oil and natural gas on oil and gas-condensate fields. Separators are the necessary pieces of equipment in processes of gas condensate treatment, gas compression and gas cooling at the final stage of field exploitation, in cycling-processing plants [5-9]. 

Depending on the kind of the substance they are designed to process, separators can be labeled as gas-oil separators and gas separators (Fig. 2.1). Gas-oil separators are used for separation of oil from oil gas, and gas separators - for separation of natural gas from droplets of condensate, water, and solid particles. Gas separators, as a rule, process gas-liquid mixtures with a rather small content of the liquid phase. But they can also operate in the so-called flood regime (when a large volume of liquid enters the separator as a result of accidental injection of water or accumulation of condensate in pipes). 

Depending on their configuration, separators can be classified as spherical or cylindrical, and depending on their spatial arrangement - as horizontal or vertical. 

The basic advantage of horizontal cylindrical separators is their high productivity. They are intended for separation of gas-liquid mixtures with high liquid content and for separation of liquids that tend to produce foam. The shortcoming of horizontal separators is the difEculty of removal of solid admixtures. This drawback is absent in vertical cylindrical separators. The elliptic bottom of these separators provides for the accumulation of liquid and solid impurities in the bottom part of the device and their removal via the drainage system. The liquid gathering section can be taken outside the frame of the separator and its shape can be either spherical or cylindrical (usually a horizontal cylinder). 

Spherical collectors are mostly used when high pressures are involved. 

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The dispersion in the mixer sections is swept under the dividing partitions into the adjacent transfer sections. If the dispersed phase is the less dense of the two its droplets rise up through the transfer sections against the down-coming flow of continuous phase after which they pass to the next mixer section where the process is repeated. Unlike a mixer-settler the ROF contactor does not depend for its operation on the coalescence of the dispersed phase in separating compartments and in its application to the nitration stage of the TNT process nitrobody separates out only at the product end where a smaller unstirred compartment operates as a true separator. 

H Drum separators are generally divided into two categories gravity settlers and impingement separators. 

Liquid waste streams with a high-suspended solids content can be cleaned up by solids removal in clarifiers, thickeners, and liquid cyclones and by accelerated settling by inclined Chevron settlers or the like [73]. For waste streams with very finely divided solids in suspension (i.e., less than about 100 pm) dissolved air flotation techniques have been shown to be more efficient than methods employing sedimentation. Final dewatering of the sludges obtained may be carried out on a continuous filter or a centrifuge. The clarified water product can be accepted for more potential options of reuse or final disposal options than untreated water, and the separated solids may be burned or discarded to landfill, as appropriate [74]. 

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