The operating cost is higher as compared to the Cold fog system as it requires
the compressed air for the bag cleaning.
Higher maintenance cost as compared to Cold Fog system requiring replacement
of bags frequently.
More equipment is Involved-Fans, RALs, limit switches, pressure switches etc.
Require large ducting work from point of dust generation to the bag filter.
6.2 Dust Suppression System (Cold Fog System)
Cold Fog system produces an ultra-fine water fog with the help of high pressure
water about 400-3200 psi, a high concentration of 1-15-micron fog droplets that
effectively attract and hold dust particles from 0.1 to 1000 microns to be removed
from the work place and other environmentally sensitive areas. The fog system
breaks water down into very fine droplets that join with the similarly sized particles
of airborne dust. Fog systems supply micron-sized droplets that maximize the
capture potential of the water, while minimizing the amount of water added to the
product. The low flow of water added through Cold Fog nozzles, typically at 0.01
to 0.05 percent by weight of the processing material and will not degrade the per
formance of the material.
The Cold fog system requires the high pressure water pumps, SS piping and SS
nozzles of different sizes depending upon the applications as well as treated water.
- Advantages
No need of expensive compressed air.
Low maintenance cost and operating cost as compared to bag filter system.
The system has little weight so the transfer towers structure design will be
economical as compared to bag filter system.
Low capital cost when used for number of transfer points.
The installation time is less as compared to bag filter. - Disadvantages
It has a limitation of the other material applications as it adds some moisture
in the material.
It requires the treated water to avoid the scaling in nozzles, pump and piping.
6.3 Water Spray System with Chemical Dosing
This system uses a chemical to lower the surface tension of the water. The
droplets penetrate deeper in to the material making it wet. It also reduces the
friction factor between the wet particles and the transfer surfaces to mitigate the
jamming issues. The chemical makes the microscopic films as a means of increasing
the adhesion of material particles. The system operates at low pressure approx.6-7 bar.
- Advantages
No need of compressed air system.
The capital cost is less than the others systems.