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System Configuration
The Genoil Crystal oily-water treatment units are designed to separate the liquid phases in six stages located within a single vessel. Each stage is devised to remove oil particles of a certain size and renders the liquid cleaner for the next stage. This ensures greater effectiveness and manageable loads for each stage. Furthermore, it also precludes undue contamination and clogging of various stages by oil, resulting in trouble free-operation.
Minute gas bubbles resulting from controlled vacuum conditions enhance the removal of oil droplets from the water stream. Vacuum is created in the stages operating prior to the circulation pump. Oil is retained at the upper portion of the stages and is gradually accumulated in collection zones.
Downstream from the pump the stages are slightly pressurized. Oil extracted in these stages is transferred continually into the collection zones through specially designed conduits. The transfer of oil occurs due to the pressure differential existing between the stages located upstream and downstream from the pump respectively. Continual oil extraction ensures outstanding cleanliness of the polishing stages and prevents accidental contamination of the effluent.
Oil accumulation in the collection zones is monitored by a probe that initiates periodic oil discharge sequences. The separator is isolated from the effluent discharge line and connected to a pressurized line. Clean water back-flushes the stages and displaces the oil from the collection zones. The oil probe resumes the separation process after a preset amount of oil is evacuated.
The first stage achieves oil-water separation through gravity, enhanced through a flotation effect by minute gas bubbles. A specially designed device imparts a rapid circular motion to the liquid. Oil migrates to the centre of the device and then ascends, accumulating progressively in a collection zone (A). Solids and sludge are deposited at the bottom of the stage for removal. Most of the oil droplets are removed in this stage.
The flow is reversed prior to the liquid entering the second stage which contains oleophilic material. Small particles of oil adhere to the surface of the oleophilic beads and are attracted to them by a surface tension effect. As they get together, the oil droplets form larger globules whose enhanced buoyancy overcomes the force of attraction exerted by the beads. The oil globules then detach themselves from the beads, move upwardly with the liquid and remain in the secondary collection zone (B) for removal. This stage is designed to allow continual agitation of the beads in order to accelerate the coalescing process and facilitate a self-cleaning process. The flow is reversed through a circular motion at the upper part of the second stage and oil remains in the secondary collection zone (B).
The liquid is further processed in the third stage entering the core of a circular basket and moving radially outwards through the coalescing material. Liquid velocity decreases towards the periphery of the basket thus allowing minute oil particles to coalesce effectively. The resulting oil globules are retained in a collection zone (C) as the liquid reverses its motion and descends towards the fourth stage.
A positive displacement pump delivers the liquid to the fourth stage for further separation by means of a vortex-generating device. Centripetal forces within the vortex agglomerate the oil particles and force them to coalesce in order to form larger globules. Furthermore, an effect similar to one created by a cyclone also agglomerates the oil particles thus enhancing the coalescing process. A perforated conduit retrieves the globules from the eye of the vortex and directs them to a dispersion plate placed above the vortex generator. Oil particles then travel through suitably sized perforations in the dispersion plate, gather around a funnel and migrate toward the oil collector of the first stage. Spinning liquid rapidly exits the vortex generator being deflected downwards by the dispersion plate.
Further separation of minute oil particles occurs in the fifth stage by means of surface tension within a specially designed device. The liquid flows radially though the device and the oil particles are forced to form clusters of larger globules. The liquid is then directed around a circular baffle devised to create a quiet zone above the device. Oil is readily left behind and then drawn into the first stage as the flow is reversed and cleaner liquid is transferred to the final filtration stage.
In most cases the separation is completed prior to this stage. However, for oils of unusually high density, the sixth stage retains the remaining particles by means of filters. The filters are designed to temporarily retain minute particles of oil on their surface. The particles coalesce and detach themselves from the filter media through their enhanced buoyancy and the sweeping effect of the liquid.
Filter media lifespan can be prolonged to significant periods of time by minimizing the amount of oil particles reaching the filter media and effectively removing the oil from its surface. |
