Separation characteristics of vortex three-phase flotation for offshore produced water treatment

Abstract

The increase of production water has led to an increasing footprint of production water treatment equipment. In order to promote the application of vortex three-phase flotation on offshore platforms, the effects of water clarifier concentration, processing capacity, gas intake volume and oil properties on the treatment were quantitatively studied. The experimental results showed that as the injection concentration of water clarifier increased, the oil concentration at the outlet of the equipment gradually decreased and then slightly increased. The suitable injection concentration of water clarifier was about 40 mg/L. When the processing capacity was lower than the design capacity, the oil content at the equipment outlet became stable and the anti processing capacity fluctuation effect was great as the processing capacity increased. When the gas intake volume was around 1% of the inlet liquid volume, the equipment had a good oil removal effect, and excessive or insufficient gas intake volume was not conducive to equipment oil removal. Vortex three-phase flotation had an efficient treatment on production water with different oil properties. When the oil concentration at the inlet of the equipment was ≤2 000 mg/L and the suspended solids concentration was ≤500 mg/L, the oil concentration in the effluent of the equipment was ≤60 mg/L and the suspended solids concentration was ≤60 mg/L. It could replace traditional inclined plate oil remover+flotation two-stage water treatment equipment to save footprint.

Keywords

• vortex three-phase flotation
• separation characteristics
• water clarifier
• gas intake volume
• processing capacity
• oil properties