LUBE OIL RE-REFINING
All mineral used oils, on the one hand, can be adequately treated and recycled.
On the other hand, their improper disposal causes environmental pollution.
The re-refining process consists in the elimination, through a suitable treatment, of the carbon residues and of the metal oxides from waste oils to obtain re-usable base oils.
CMBITALY-TECHNOILOGY Process, through its most advanced available technique, can recover from 100 kg of dehydrated waste oil:
- 76 kg of new oil;
- 13 kg of additive for bituminous membranes;
- 8 kg of low sulphur content automotive/combustion gasoil;
- 3 kg of by-products suitable for energy requirements inside the factory.
STEP 1. PREFLASH
The used oil is heated up to 140°C and then distilled in a vacuum column, where the water and light hydrocarbons are separated.
STEP 2. DE-ASPHALTING
The dehydrated oil is distilled at 360°C in a static vacuum de-asphalting column, where the asphaltic and bituminous products remain in the bottom and, at the same time, a vacuum Gasoil is extracted at the top of the column. In the column a special de-fouling and bleaching additive is injected in order to minimize the equipment fouling and restore the base oil color.
STEP 3. FRACTIONATION
The oil without impurities and de-fueled is sent to a fractionated distillation column where the lube oil is fractionated into different grades of different viscosities. On the bottom of the column the compounds that have reacted with the additive are extracted.
At the end some Gr. I+ base oil fractions are produced.
Should the oil be upgraded to Gr. II/II+ an Hydrofinishing is added.
STEP 4. HYDROFINISHING
The oil and hydrogen are heated up to and then sent to some reactors containing a catalyst favoring hydrogen reaction with the unsaturated compounds, sulphur and nitrogen.
The final result is a water white clear oil with very low sulphur and polynuclear aromatics (PNAs) content in compliance with API Gr. II/II+ specifications. The intermediate Gasoil can be hydrotreated as well for producing a low sulphur Diesel.