At top of packing tower demister mist eliminator acts as a key
tower internal
Demisters are also a kind of key tower internals. They are used at the top
of a packing tower or in conjunction with a collecting tray between
two packed beds. The eliminates liquid droplets from the gas
stream, so that the mist discharged from the tower or the liquid
entrainment from one stage to the next is minimized.
Usually we produce and supply two main kinds of demisters, wire mesh demister and vane pack demister. Where wire mesh demisters are concerned, droplet coalescing leads
to increased droplet size allowing the discharge of these droplets
from the demister. These demisters are recommended in particular
for systems where no solids buildup can occur. Additionally, some
engineering design can be done with the wire mesh type and bulk density of the mesh pad, to best suitable for the working conditions.
In vane pack demisters, the gas flow is deflected several times so that the liquid
droplets impinge on impact surfaces where they then flow from these
in a downward direction. Scaling of solids can be avoided or reduced with the use of spray
nozzles situated above the demister.
Popular Metal Wire Mesh Demister Type and Applications
Wire Dia. Mm | Mesh Density Kg/m3 | Surface Area M2/m3 | Normal Micron Rating | Application |
| 0.15 | 195 | 650 | 3 | Very high efficiency in clean service |
| 0.15 | 145 | 480 | 4 | Fine droplet removal in clean service |
| 0.15 | 112 | 375 | 5 | General purpose in clean service |
| 0.28 | 195 | 355 | 5 | Optimum efficiency & pressure drop |
| 0.28 | 170 | 310 | 6 | General purpose not totally clean |
| 0.28 | 145 | 265 | 8 | Heavy Duty e.g. Oil & Gas Separators |
| 0.28 | 110 | 200 | 10 | Light fouling |
| 0.28 | 80 | 145 | 12 | Moderate fouling |
Demister position and simple drawing:
When we decide what type of internals are best suitable for a given
tower, like for distillation, fractionation or other mass transfer
process, we must consider many factors. The desired capacity,
efficiency, turndown, pressure drop, corrosion, fouling and
previous plant experience are all of importance.
Hualai has successfully served the process industries such as oil
refineries, chemical plants, etc. Let us apply this experience to
your project to assure a successful result and continued success of
your plant.
Materials of construction
Tower internals can be made of types of materials. Usually it is
carbon steel or stainless steel. However exotic metals such as
Hastelloy alloys, titanium and other steel types are sometimes
required.
There is a brief list of possible materials below.
Carbon Steel / 410 Stainless Steel / 304 Stainless Steel / 316L
Stainless Steel / 321 Stainless Steel
Monel / Inconel / Nickel / Titanium / Duplex 2205 / Hastelloy
alloys
Please specify if you need other materials not listed here.
Welcome your contact with your private tower internals plan or
ideas!
