TREATMENT OF HIGH DENSITY FUEL
If the residual fuel has a density greater than 991 kg/m3 at 15°c, an alternative arrangement to the traditional purifier is required. One such arrangement is the ALCAP system, by which up to a density of 1010 kg/m3 at 15°c can be treated.
Westfalia's OSC series separators having ALCAP system have throughput Capacity of 4000 Ltrs/hr to 43.100 lit/hrs are compact, high capability and high cost efficiency ratio. In addition to higher flow retes, it is said to require less overall maintenance and offer extended servicing intervals between 8000 and 16000 hrs, partly thanks to a reduced number of components.
The centrifuge basically operates as a clarifier and does not require any water gravity tank or there is any need of changing gravity disc due to change in density. It employs electronically operated water content monitoring system and a sludge monitoring system which allows it to automatically adjust to different fuel oil qualities and optimise treatment.
Clean oil is continuously discharged from the clean oil outlet by clarifier action and any free water and separated sludge accumulate at the periphery of the bowl. When the sludge space is filled up, the separated water approaches the disc and traces of water start to-escape with the clean oil. A sensor measures the conductivity of a partial stream of the bowl content and activates the water discharge mechanism when necessary ensuring that only water-free fuel leaves the separator.
The second monitoring system simaultaneously monitoring the solids loading the bowl. A pressure switch keeps a check on the pressure of a partial stream of bowl content and automatically triggers a bowl ejection when the optimum solids level in the sludge space is reached. Additional adjustable time - dependent ejections ensure optimum solid concentration, even with a low solids loading in the oil, underwriting the highest separation efficiency. With this method, treatment process is carried out in a single stage.
ALFA - LAVAL : When water is detected in clean oil outlet, the water in the bowl is discharged either : (i) with the sludge through the ports at the side of the bowl by bowl movement which is controlled partial discharge or (ii) through the water drain valve. Separated water is normally discharged with the sludge (approx 70% of the space outside of the disc stack). As the sludge discharge is timed to take place approx. once every fifteen minutes. If water is detected during the 15 min period by the sensor since the last sludge discharge, the separated water is discharged through the water drain valve (solenoid valve in the water-discharge line). This would occur if excessive water contamination exists. The centrifuge used in the ALCAP system is neither a traditional separator nor a clarifier. it operates in a similar way to a clarifier, but water can be discharged intermittently from the bowl.
INDEX ADV ENG NEXT