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Process
Three stage system comprising:
Wiped film evaporators
There are two wiped film evaporation vessels (WFEs). These are vertical vessels comprising a heated outer jacket and central rotor onto
which wiper blades are attached. Feedstock is fed into the WFE at a set rate and then spread into a thin film onto the heated internal surface where it is evaporated. The system operates under a vacuum.The
evaporated oil or distillate is removed from the top of the WFE. Residue is removed from the base of the WFE (residue from No1 WFE is passed on to No 2 WFE for reprocess. Residue from No 2 WFE is rejected)
Lube oil cut - The first WFE cuts distillate up to spindle oil (approx. 100 RS) and the residue passes onto number 2 WFE.
In number 2 WFE the distillate cut is adjusted to give the base oil of interest (150 solvent neutral) and the residue passes on for
blending to make RFO.
Distillate passes from the WFE to the solvent extraction plant.
Solvent extraction - The solvent extraction consists of a five-stage counter current wash with solvent. Dirty oil enters one side of the
wash tanks and clean solvent enters the opposite side. The oil moves progressively across the system being washed by systematically cleaner solvent and then exits clean on the clean solvent side. Thus the solvent
becomes more contaminated and exits on the dirty oil side.
On exiting the wash phase the oil contains approx. 10% solvent and the solvent is approx. 10% oil. This solvent is separated from the oil
by use of a flash tower and vacuum and the solvent recycled for use again. The oil is separated from the solvent by use of 2 flash towers leaving the highly contaminated oil to be pumped away for blending into RFO,
and the clean solvent recycled to use again.
At this stage there is approx. 0.1% solvent in the base oil.
Molecular filtration - This process uses columns packed with a molecular filter medium. The oil is pumped into the top of the column and
down through the column where any residual contamination becomes trapped within the molecular medium.
Once the medium is exhausted, usually noted by color change in the exiting base oil, the columns are shut off and drained for 24hrs. Once
drained the columns have a vacuum applied to the bottom and a flame is applied to the top and all the contamination is burnt off.
The columns are now regenerated.
Equipment
- (2) Weaverbrook WFEs with internal U-bundle top header allowing withdrawal and access to rotor Blades and tubes.
- Design Vessel Full Vacuum Jacket 3.0 Bar Pressure
- Design Temp: Vessel 400C Jacket 400C
- Rotor Drive: 7.5 kW motor via belts and pulleys to a reduction gear unit.
Thermal Fluid Heater
- Model: Beverly Mk 111
- Heat output: 2.4x106 BTUs/H
- Max working Temp: 320C
- Max working Pressure: 100 psi
- Fluid: Marlotherm
Vacuum Equipment
- Model: 2 x Edwards DP250 Drystar Vacuum Pumps.
- Operating Pressure range: 1000 0.4mbar.
- Model: 1 x Edwards EH 2600 Vacuum Booster Pump (WFE 1)
- Operating Pressure range: 0 1000 mbar
- Model: 1 x Leybold WAU 1000 Vacuum Booster Pump (WFE 2)
Pumping Equipment
- Feed Pump: 1 x Ingersoll Dresser 5GAUMN Gear Pump (11/2) coupled to a Carter reduction gearbox.
- Residue Pumps: 4 off (2 on each WFE) Girdlestone 2191E directly coupled to a 5.5kw motor.
- Distillate Pump: 1 x Girdlestone 11/2 F6M, 1.5kw motor (WFE 1).
- Distillate Pumps: 2 x SIHI Pumps CEHA 1202, .75kw motor (WFE 2).
Base Oil Recycling Process
- Feedstock selection
- Garage based waste oil, free from fully synthetic lubes.
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