Abstract:
Cyclone separators have been described in detail and, although substantial research has been
performed on solid / gas devices, the use of cyclones for gas / liquid separation has been
comparatively ignored; this is particularly true for higher concentrations of liquid and for
degassing applications. Consequently no generic models are available which will predict
separation efficiency or pressure drop for all designs of cyclone.
A novel design of axial flow cyclone called WELLSEP was examined for the purpose of
degassing. This design was not believed to be optimal and no design criteria or performance
prediction models were available for it. An experimental programme was therefore produced
and executed to investigate changes in geometry and the affect of fluid dynamics. Changes to
the length, vortex finder and swirl generator were examined first and then one design was
selected and tested over a number of liquid flow rates, Gas Void Fractions (GVFs) and liquid
extractions.
Data was collected from the experiments which assisted in the development of semi-empirical
models for the prediction of pressure drop and separation efficiency. These models could be
used in the design of WELLSEP.
Geometric and fluid dynamics changes have both been shown to influence the performance of
the tested cyclone. The principal conclusions that have been drawn from this research are:
" Of the tested designs, the design based upon a 30mm vortex finder diameter, settling
chamber length of three times the diameter of the cyclone and a four start helix gave the
optimum separation efficiency over the greatest range of conditions.
0 The separation efficiency is affected by the superficial liquid velocity and the liquid
extraction but not the GVF.
" The dimensionless pressure drop coefficient (Euler number) is a function of liquid
extraction and GVF. It may also be a function of the superficial liquid velocity but it is unproven by this research.
