SINOKLE CDFU Process: An Innovative Way to Break the Bottleneck in Oilfield Produced Water Treatment
For a long time the mainstream processes for oilfield produced water have been inclined-plate settling tank plus filtration, and conventional dissolved gas flotation (DAF) plus deep filtration, but both have serious shortcomings. The former gives unstable results and poor tolerance to water quality swings, needs large doses of chemicals and readily generates oily sludge and other secondary pollution. The latter is somewhat more efficient but requires a long hydraulic retention time (15-40 minutes), a large footprint and a low degree of automation, making it a poor fit for the efficient development of modern oilfields.
Against this backdrop, the CDFU (cyclonic dissolved gas flotation) process developed by SINOKLE emerged as a revolutionary solution for oilfield produced water treatment. The CDFU process relies on purely physical separation: a unique cyclonic dissolved-gas design combines centrifugal separation with micro/nano-bubble flotation to achieve highly efficient removal of oil and suspended solids.
Its working principle is clear and efficient. Produced water enters the unit through a lift pump and forms a stable flow field under the cyclonic action, where free oil, emulsified oil and suspended solids collide rapidly with the 5-30 micrometre micro/nano bubbles generated by dissolved gas and adhere to them. Surface tension of the bubbles gradually ruptures the emulsified oil film, achieving physical demulsification; the oil-laden bubbles and suspended solids gather and rise to the collection barrel at the top and are discharged under their own pressure into the slop tank. The treated water flows on to downstream processes by lift pump, and off-gas is routed separately to the treatment system, with fully automatic closed-loop control throughout.
Compared with conventional processes, the advantages of the SINOKLE CDFU process are especially pronounced.
First, treatment is efficient and stable: single-stage oil removal exceeds 90% and emulsified oil in the 0.1-20 micrometre range is removed precisely, with no loss of performance even when water quality fluctuates.
Second, it is genuinely green: no chemicals are added at any stage, oily sludge is eliminated at source, there is no secondary pollution, and the equipment runs fully enclosed under pressure with no fugitive odour or gas.
Third, the economics are compelling: the skid-mounted design cuts the footprint to one third of a conventional process. At a 180 m³/h project in Daqing, for example, the unit occupies less than 30 m² and the treatment cost falls to RMB 0.2 per tonne of water, only one fifth to one third of the conventional cost.
Fourth, it is highly intelligent: IoT-based remote control, a structure dominated by static equipment that greatly reduces maintenance needs, and long inspection intervals all deliver significant labour savings.
