source: publication recyclingmagazine—june 2013 fog
TRANSCRIPT
It is a fact that sprinklers and water
jets have already been used for a
long time to control dust, but the
Belgian company Jet-Zone bvba
in Zwevegem, an affiliate of Savic
Engineering, is doing it much more
efficiently. Their technology con-
sists of two basic principles:
- A very fine spray covers a very
large surface over which dust
particles can be caught. The vol-
ume of water in a standard sized
rain drop is equivalent to 8,000
spray particles.
- Control at source. The most effi-
cient way to eliminate particu-
late matter, which also gives the
best results, is controlling it right
where it is generated. In this
case, that happens to be the
crusher chamber. That is exactly
where Jet-Zone injects its fine
mist.
Principle
The water spray principle in itself is
relatively easy. “Take an injector
with a sufficiently small opening,
apply high water pressure and
there you go, there is your water
spray”, says Jet-Zone director Ni-
colas Malfait . “The innovating
part of our water spray technolo-
gy however is the injector’s loca-
tion, completely fitted within the
crusher chamber and still perfectly
protected against the shredded
material’s impact.”
The art consists of catching as
much dust as possible with the
spray without moistening the ma-
terial. This is a fundamentally differ-
ent and better approach than all
existing technologies. The power-
fully injected spray permeates
deep into the crushing chamber’s
core giving an even spread of
spray thereby delivering the best
performance.
Additive
Malfait explains also that: “In order
to further improve attaching the
dust particles to the spray parti-
cles, we have developed an addi-
tive. First we examined the dust’s
characteristics. Within the crusher
chamber itself, heat is generated,
causing the water to evaporate.
The additive on the other hand
enables the dust particles to bind,
making them heavier and causing
them to drop down again on the
shredded material.” Thanks to the
limited volume of water, the mate-
rials’ stream does not get wet and
the quality of the resulting materi-
als’ stream improves. Malfait also
says: “Moreover, the little bit that’s
left for landfill does not get any
heavier and therefore increased
dumping costs because of the
added water are no longer an
issue either.”
Innovation
The system’s innovation is its injec-
tors and intelligent control. Malfait
also says:“The injector must survive
in a chamber which also houses a
rotor doing its destructive work
and that is not an easy task. Mate-
rials are banged with great force
against the chamber’s walls and
the injector must be able to resist
that.”
Jet-Zone has designed an intelli-
gent version which does not re-
quire any adjustments to the
crusher chamber. In order to pro-
tect the crusher chamber itself,
wearing plates are fitted using
If there is one activity where dust is generated, it is when car wrecks
are recycled using giant shredders. That is because cars are mainly
made of textiles and quickly crumbling plastic materials. In an effort
not to burden the environment too much when crushing a car wreck,
all sorts of techniques are implemented to control any dust generat-
ed. Recently another technique has been added to that list: control
at source using a fine water spray.
Fog-Injection against shredder dust
Source: publication Recycling-Magazine—june 2013
Picture 1: Dust generation before (a) and after (b) fitting Jet-Zone’s equipment; improvement is clearly visible
bolts. Depending on the crusher’s capacity 2, 4 or 6 bolts are re-
moved and replaced with injector
holders.
The injector holder’s size is the
same as the bolt’s and can also
be used to tighten the wearing
plate again. The holder has an
opening which fits the Jet-Zone
injector perfectly, protecting it
against the powerful bangs. The
injector is also fitted with a spring
so that it can absorb a certain im-
pact. Auxiliary components such
as high pressure hoses are located
outside of the crusher chamber
and all other components such as
high pressure pumps and their
controls are located in a contain-
er placed outside of the machine.
Results
Thanks to injecting a water spray
right within the chamber’s core,
using 500 to maximum 2,000 litres
of water an hour when producing
300 tonnes of material per hour,
particulate matter emissions are
greatly avoided. The volume of
water is easily controlled. Under
damp weather conditions, less
spray is needed than for example
during hot summer days with low
humidity levels. The volume of wa-
ter can be manually adjusted and
employees can easily see if suffi-
cient spray is used.
In practice
Cometsambre, an affiliate of the
Belgian Comet group (see frame),
is one of the first users of the Jet-
Zone system. Implementation of
the system is managed by Vincent
Bodson, managing director of
Comet Technique, the depart-
ment responsible for implementing
new techniques. He explains: “The
Jet-Zone fog injection fits perfectly
in our quest for lower particulate
matter emissions, whatever source
they are from. We have placed
meters all around our site in order
to gauge once a month the
amount of dust caught. After in-
stalling the Jet-Zone fog injection,
this amount has halved, which is a
fantastic result, especially if you
take into account that it is not only
us who generate dust, but other
factories as well, such as the ce-
ment factory next door. We can
therefore confidently assume that
Jet-Zone reduces the crusher’s
emissions by more than 50%. I
have actively been looking for
solutions for more than 20 years
and I believe that with the Jet-
Zone fog injection, we have at last
found a decent working system.
Our water consumption has also
been drastically reduced be-
cause we no longer have to apply
jets of water in order to control
dust generation, thereby also re-
ducing our dumping costs. Anoth-
er couple of advantages are that
our installations remain clean and
there are no water puddles
around them.”
COMET GROUP AND THE ENVIRONMENT
Cometsambre, an affiliate of the Belgian Comet group, has a recycling plant in Obourg (near Mons) and in Châtelet (near Charleroi). Obourg is the location of Europe’s largest shredder: it is a 7,000 hp (more than 5 MW) Metso Lindemann Power Zerdirator with a capacity of 300 tonnes per hour. Cometsambre’s main activity is recycling ferrous and non-ferrous materials. The main stream leaving Obourg’s shredder is immediately usable by the foundry and any auxiliary streams are taken to Comet Traitements, also in Châ-telet. Vincent Bodson is Comet Technique’s managing director and responsible for managing the introduction into this department responsible for implementing new techniques and developments. He says: “The Comet’s group philosophy is to fully comply with all envi-ronment requirements and in order to do that use the best technologies available.”
Picture 2: One injector’s spray jet. It is clear to see that the injector has been fitted fully protected