|
Solid particle which, depending on their size, are sub-divided
in coarse and fine dust. Whereas coarse dust particles remain in the air only
for a short time, fine dust particles can remain in the Atmosphere
for a longer period, where they are also transported over great distances.
Dust originates both from natural sources and from sources which are influenced
by humans. Depending on ist physical size and the substances (e.g.
Heavy Metals) adhering to it, dust is more or less harmful
to the health. Dust can be separated from Waste Gases
by a variety of methods:
- Centrifugal separator (e.g. cyclone, Inertia Force
Separator): Diversion of the Waste Gases, in conjunction
with which the dust particles are only able to follow the diversion with
difficulty, and are thus separated. This is a method which exhibts poor
efficiency, since the fine dusts in particular, which are potentially injurious
to the health, are only poorly separated.
- Wet separator (e.g. venturi washer): A liquid is sprayed into the
Waste Gases, the droplets of which bind the dust particles
and in so doing wash them out of the Waste Gas. The
washing water must then be cleaned to remove the dust particles.
- Electro-filter: The application of an electrical
charge to the dust particles, and their diversion past the so-called collecting
electrodes. Electro-filters are highly efficient, including
with the fine dust particles, and are consequently used for the cleaning
of Waste Gases from Power Stations.
- Filtration Separator: The separation of the
dust by means of fibrous filters. The cleaning effect is enhanced by the
“filter cakes” which are built up of their own accord from the dust
particles on the inlet side. Filtering separators exhibit an even
greater cleaning efficiency than Electro-filters, although their energy requirement
is higher.
|