Fundamental studies have shown that the separation efficiency of cyclones is significantly impacted by fluid types, gas load, liquid load and pressure.

For example, model fluids used by vendors have consistently better separation efficiencies than genuine hydrocarbons tested under realistic reservoir conditions. The surface tension between gas and liquids also has an enormous impact on efficiency.

At higher pressures and lower temperatures, surface tension is reduced to such an extent that the integrity of the liquid droplets breaks down alarmingly, resulting in the separated moisture being swept along again (re-entrained) with the flow.

This makes it difficult to predict the efficiency of a cyclone prior to its installation in a scrubber, and no theory exists to help overcome this problem.

However, by mathematically modelling cyclone geometry and flow and fluid properties, it has been possible to devise a brand new relationship that correlates extraordinarily well with separation efficiency – the so-called re-entrainment number.

The correlation shows that fluid properties are far more susceptible to high pressure than previously thought, and that liquid carry-over is governed more by a general re-entrainment process than in the normal form of small droplets.

The result is important for designing the next generation of gas scrubbers.