Dedusting
Electrostatic precipitators
The dry electrostatic precipitators are considered the standard in dust removal in many industries as, for ex ample, power industry, metallurgy or the glass industry. Peculiar characteristics of this equipment is possibility to work in high operating temperatures, up to 470 C, and at the same time ability to give good efficiency, about 90 – 99%, in allow the reach of emissions values as low as 20 mg/Nm3.
These devices utilize electric fields to move the particulate present in the gaseous stream on the collecting plates. Once on the plates such powder is removed by means of a rapping system, realized by the use of rotating hammers which allow the vibration of these elements and the separation of the particulates by the same. The dust will be collected within particular hoppers and through the same evacuated with a system of screws. Their structure allows a wide modularity of the ESPs that, regarding the process conditions could be realized in one or more electric fields in series, and with different dimensions both in height and width in order to satisfy the customers’ requests and for the environmental limits and regarding the available place to realize such installation.
Fabric filters
The fabric filters are among the equipment that can provide the best results in performance level with regard to the dust removal. The working principle is very simple: in a pulse jest fabric filter, a wire cage in each bag keeps it from collapsing during normal filtration. As the flue gas passes from the outside of the bag through the filtering media, the particulate forms a cake on the surface of the bag. Cleaning the filter bags is accomplished by introducing controlled pulses of compressed air into each filter bag through a blowpipe and orifice assembly mounted just above the filter bag. The accumulated dust cake is dislodged by the resulting shock wave and falls into the hoppers.
The dust is conveyed from the hoppers away from the fabric filter by an ash transport system for beneficial re-use or disposal.
Control Process’s control system provides plant operators with the flexibility to select the best combination of operating modes and cleaning logic to maximize availability and minimize maintenance costs. The different modes can include on-line, off-line and manual cleaning.
