Process Components FLOTTOPAC®
The FLOTTOPAC® process can be divided into three functional steps: the mixing zone, the separation zone and the recirculation for the production of supersaturated water.
In the central mixing chamber, the basis for an effective flotation is established. Here microbubbles and particles or droplets must join. Sufficient resident time and an optimal flow design result in high probability of contact between microbubbles and particles, without destruction of already formed particlebubble aggregates due to shear forces.
In the separation zone, the aggregates accumulate as flotate on the surface while the clarified water flows downward and is drawn off as clear water. The flotate and bottom sludge accruing in smaller amounts are removed via robust scrapers.
A partial flow of the clarified water is brought into contact with gas in a saturation system at a pressure of 4–7 bar, at which the point the gas is dissolved. Typically, air is used; but in hazardous areas, nitrogen can also be used as a substitute. The water is then depressurised via special valves directly upstream of the mixing chamber. The combination of strong supersaturation and an abrupt depressurisation leads to the formation of microbubbles usually within a size range of 40–80 microns in diameter. After mixing with the feed water of the mixing chamber, more than 80 million microbubbles per litre are available to adhere to particles and droplets.