The mist eliminator is mainly composed of wave blade, plate, clip
strip fixing device in wet desulphurization absorption tower in the
process of operation, easy to produce 10--60 micron particle
diameter "fog", "fog" not only contains water, it is dissolved with
sulfuric acid, sulfate, sulfur dioxide and other two at the same
time, also caused contamination blower, heat exchanger and flue and
severe corrosion, therefore, wet desulfurization process of
absorption equipment proposed demisting requirements, mist gas be
purified before leaving the absorption tower.
The mist eliminator is used to separate the liquid droplets from
the gas in the tower, so as to ensure the mass transfer efficiency,
reduce the loss of valuable material and improve the operation of
the compressor. Can effectively remove 3--5um droplets, if set
between trays of demister, not only can guarantee the efficiency of
mass transfer tray, can also reduce the plate spacing.
So the mist eliminator is mainly used for gas-liquid separation.
Air filter can also be used for gas separation. In addition, the
screen can also be used as the instrument industry in various types
of instruments in the buffer, to prevent the interference of
electronic shielding, etc..
Wet desulfurization, it is also dissolved in sulfuric acid,
sulfate, sulfur dioxide, etc.. If not properly resolved, any into
the chimney fog",
Three dimensional simulation of desulfurization system
In fact, the sulfur dioxide emissions into the atmosphere, but also
caused by fans, heat exchangers and flue gas pollution and serious
corrosion. Therefore, the wet desulfurization process on the
absorption equipment put forward the requirements of fog, purified
gas before leaving the absorption tower to remove fog. Demister is
the key equipment in FGD system, and its performance directly
affects the continuous and reliable operation of wet FGD system.
The trouble of demister will not only cause the outage of the
desulfurization system, but also may cause the whole unit (system
The arrangement of the mist eliminator is the most common type of
flat plate arrangement and roof arrangement.
When the gas containing entrainment at a certain speed through the
demister, because the gas inertia impact force, entrainment and
wave plate collision and the droplets are together to its own
gravity over the gas lift and liquid surface tension, droplet from
corrugated plate surface break down. Multi fold demister with
corrugated plate structure to increase the mist captured the
opportunity, not removed the mist at the next corner after the same
role was arrested, so repeatedly, thus greatly improving the
After the gas passes through the corrugated plate demister, the gas
is basically free of fog. The flue gas passes through the mist in
the curved channel, the inertia force and gravity the droplets
entrained in the stream separated: after flue gas desulfurization
at a certain speed through the demister, flue gas is rapid and
continuous change of the direction of movement, because of the
centrifugal force and the inertia effect of the flue gas inside the
droplet impact to removal mist leaves trapped down, forming a water
droplet collection, by gravity, fall into the slurry tank, the
gas-liquid separation, which flows through the flue gas removing
mist to mist after discharge.
With the increase of the air velocity, the mist removal efficiency
of the demister increases, which is due to the high flow velocity
and the inertia force acting on the droplet. However, the increase
of flow velocity will increase the system resistance and increase
the energy consumption. And the increase of flow rate has a certain
limit, the flow rate is too high will cause two times with water,
thus reducing the efficiency of fog.
Usually through the demister section of the highest and without
definition of the two velocity of flue gas with water when the
critical velocity, the velocity and the mist eliminator system
structure, water load, flow direction, in addition to the factors
related to the mode of arrangement of mist. Design velocity is
generally selected at 3.
5 - 5.5m/s.
The diameter of the dispersed droplets in the usual chemical
operation is about 0.1 ~ 5000 m. Generally, the particle size of
100 m or more can be solved easily because of the rapid
sedimentation rate. The droplet diameter is larger than 50 m, the
available gravity sedimentation separation; more than 5 mu m
droplet collision and available inertial centrifugal separation
method; for smaller mist to try to make it together to form larger
particles, or by fiber filter and electrostatic precipitator.