What are methods of oil supply in C.O.W or crude oil washing ?

There are basically three wash oil supplying methods so called ―

1. Bleed-off System.
2. Closed Cycle
3. Open Cycle

1. Semi-open Cycle System:-
   • Wash oil is introduced from a tank being discharged and drained oil is discharged into the aftermost centre tank or slop tank.
   • Precaution:- The tank be used as a source of crude oil washing (Driving Oil) should be first discharged at least one metre in depth before supplying as a washing medium to suppress electrostatic charges.
2. Closed Cycle System (re-circulation method):-

Wash oil is supplied from the aftermost centre tank or slop tank and drained oil is collected in the same tank, i.e., the same tank is used for both purposes