(112g) The Influence of Surface Tension On the Performance of Mist Separator, Part II

The influence of surface tension
on the performance of mist separator

Part 2: Effect of density, wettability and co knit
material

Wolfgang Heikamp, Rhodius GmbH

Armin Pitzer, Rhodius GmbH

Attilio Praderio, Conoco Philipps

Prof. Dr. Michael Schultes, Raschig GmbH

In many chemical,
refinery and petrochemical processes wire mesh mist separators are installed to
remove fine droplet from gas streams. The design of these separators are mostly
based on the following equation using a wire mesh characterizing K- factor,

Vc= K  QUOTE
 
         ρ
= ρ_L

Vc= design flow velocity

This equation ( Saunders ? Brown ) became an
industrial standard to calculate a knitted wire mesh separator. There are
many  individually proposal for the K
factor at different application.

Another  design
criteria was initially recommended by Bürkholz, based
on many test datas, which can also used for the
estimation of  the flooding velocity. Vc
as a function of the L/V liquid/gas mass flow ratio, the density difference
between liquid and gas Δρ and the liquid density ρ_L.

It has to be noticed that this equation does not take
into account any surface tension and wettability effects and is only proved for
air/water systems. Based on other gas/liquid separation processes it is well
known that low surface tensions (especially below 20 mN/m) are reducing the
flooding velocity of equipments.

In recent experimental studies with commercially
available mist eliminators the influence of 
surface tension, wettability and co knit material on the flooding
velocity was newly investigated. A test rig was developed to study the flooding
performance of mist eliminators with surface tensions from 68 mN/m down to 12 mN/m.

The results of these experimental investigations will
be presented and compared to literature data. In addition an outlook will be
given for further work.