| The performance of four CAT-FLOC coagulants, CAT-FLOC 2963, CAT-FLOC 2973, CAT-FLOC 7965, and CAT-FLOC 8964, for separation of Castrol GTX 10W-30 motor oil and water emulsions by dispersed air flotation are compared. The flotation unit used is a bench scale unit and air is dispersed through a nylon membrane. Two different membranes were used, one with a 10{dollar}mu{dollar}m pore size and the other with a 20 {dollar}mu{dollar}m pore size. Three different initial concentrations of oil in water, 3.1%, 5.7% and 7.0% by volume were examined. Each CAT-FLOC exhibited a pattern of separation efficiency which was directly related to its relative concentration in a particular oil-water emulsion. Under-dosing the emulsion with a particular CAT-FLOC resulted in better separation than proper dosing or overdosing. Proper dosing, i.e. the amount of CAT-FLOC needed to react with most of the oil suspended in an emulsion to form coagulant, created a dense, fast-settling floc which interfered with the flotation process of the air steam. Overdosing resulted in coating of the suspended droplets to form particulate matter which behaved similarly to the original oil droplets. |
PDF Full Text Request