Note: Descriptions are shown in the official language in which they were submitted.
CA 02753662 2012-12-06
Method and Device for Engine Exhaust Gas Scrubbing
The invention relates to a method and device for engine exhaust gas scrubbing,
in
particular of a large engine, preferably a two stroke large Diesel engine.
From EP 1 230 969 Al, a method and device for exhaust gas scrubbing of a
vehicle engine are known where the exhaust gas to be scrubbed is introduced
into
an oil bath without pre-treatment by means of a perforated tube above which
bath
a perforated cover is located as a splash guard. Thus, a comparatively short
contact time of the exhaust gas with the scrubbing liquid formed here by oil
occurs
which may have an unfavourable effect for take-over of the contaminants
contained in the exhaust gas by the scrubbing liquid. Moreover, comparatively
large gas bubbles occur in the oil bath, which only on its surface get into
contact
with the scrubbing liquid, but include a comparatively large gas volume which
still
increases the above mentioned disadvantage. Therefore, only a comparatively
small cleaning effect is to be achieved.
Therefore, it is the object of the present invention to provide a method of
the above
type which ensures a high degree of scrubbing. It is another object of the
present
invention to provide a device for performance of the method according to the
invention, which is of simple design and permits achievement of optimum
process
results.
The fine droplets of the scrubbing liquid introduced into the exhaust gas
capture
and bind the solid particles contained in the exhaust gas and the gases to be
scrubbed from the exhaust gas, with a comparatively lot of time being
available for
these processes due to an early central admission of dispersed scrubbing
liquid
into the exhaust gas so that the contaminants contained in the exhaust gas are
CA 02753662 2011-08-25
reliably absorbed by the scrubbing liquid. In the subsequent passage of the
aerosol flow comprised of exhaust gas and dispersed scrubbing liquid through
the
scrubbing liquid bath, the liquid portion of the aerosol introduced is already
largely
absorbed, with the particles absorbed by it and the scrubbed gases passing
over
to the scrubbing liquid in the scrubbing liquid bath, and being discharged
with it.
The receptacle taking the scrubbing liquid bath gets permanent liquid supply
by
the dispersed scrubbing liquid introduced into the gas to be scrubbed, so that
the
contents of the receptacle are permanently renewed and the contaminants
collected from it are reliably discharged. A high degree of scrubbing can
therefore
be expected from the measures according to the invention.
Advantageous embodiments and adequate further embodiments of the generic
measures are indicated in the dependent claims and are described more in
detail
in the subsequent description of an example by means of the drawing.
In the accompanying drawing:
Figure 1 shows a longitudinal sectional view of an exhaust gas scrubbing
device according to the invention,
Figure 2 shows a section along line II/11 in figure 1,
Figure 3 shows a section of a sump provided for collecting a scrubbing liquid
bath,
Figure 4 shows the assembly according to figure 3 in operation,
Figure 5 shows a sump assembly of a scrubbing device according to the
invention installed, for example, on a ship, which is inclined relative
to the horizontal,
Figure 6 shows a schematic view of a two stroke large Diesel engine with
exhaust gas recirculation and scrubbing,
Figure 7 shows a schematic view of a two stroke large Diesel engine with a
scrubbing device built into the exhaust pipe,
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Figure 8 shows an alternative of figure 1,
Figure 9 shows an example of a Venturi assembly assigned to a pipe socket,
Figure 10 shows an alternative of figure 9 with internal flow body,
Figure 11 shows an alternative of figure 10,
Figure 12 shows a vertical section of the bottom end of a pipe socket with
assigned valve body and
Figure 13 shows a plan view of the valve body according to figure 12.
The main field of application of the present invention are large engines, in
particular two stroke large Diesel engines, as they can be used, for example,
as
propulsion systems for ships or for stationary power stations or similar.
The exhaust gas scrubbing device, which is the object of figures 1 and 2,
contains
a barrel-type receptacle 1 which is received on a supporting frame 1a provided
with feet. The receptacle 1 comprises an exhaust gas inlet 2 located on the
front
side and an exhaust gas outlet 3 discharging here towards the top, and is
provided
with a water outlet 4 on the lower side. The exhaust gas inlet 2 is connected
with a
supply line 50 chargeable with exhaust gas.
The barrel-type receptacle 1 is comprised of a cylindrical centre portion
which is
closed by two lids flanged on the front side. The exhaust gas inlet 2 is
located here
in the upper area of a frontal lid. The exhaust gas outlet 3 is located here
approximately in the centre of the vertex area of the cylindrical centre
portion.
Advantageously, in the area of the centre portion and/or the lids at least
one,
preferably several portholes 5 are provided via which what happens inside the
receptacle 1 can be observed from outside.
The inherent pressure of an exhaust gas leaving an engine and/or its exhaust
turbo charger is supposed to be sufficient in the present example in order to
flow
through the receptacle 1. In the present example it is therefore defined as a
pressure vessel which resists to the high exhaust gas pressure. Additional
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conveying means for the exhaust gas are not required here.
In the upper area of the internal space 6 of receptacle 1, an assembly with at
least
one horizontal distribution pipe 7 is provided, which extends approximately
over
the length of the centre portion of receptacle 1 and communicates with the
exhaust
gas inlet 2. In the example shown, several, here three, parallel distribution
pipes 7
adjacent to each other are provided, as can best be seen in figure 2, which
are
connected with the exhaust gas inlet 2 via a distributor piece 8 coupled to
the
exhaust gas inlet 2 and provided with a corresponding number of connecting
sockets. From each distribution pipe 7 several branch sockets 9 distributed
over its
length and defined by vertical pipe sockets branch off towards the bottom
which
each take up a partial flow of the exhaust gas volume flow fed to the
associated
distribution pipe 7. In the example shown, as can be seen in figure 2, the
branch
sockets 9 branching off towards the bottom from the three distribution pipes 7
are
located each in the form of rows extending transversely to the receptacle
axis.
In the embodiment shown with division of the exhaust gas flow taking place
within
the receptacle 1 to the branch sockets 9, the distribution pipes 7 can
advantageously act as heating elements which can release heat to a medium
passing by, for example the scrubbed exhaust gas flowing towards the exhaust
gas outlet 3. But in many cases this is not desired or necessary. In such
cases,
division of the exhaust gas flow can also occur to the individual branch
sockets 9
also outside receptacle 1. The distribution pipes 7 connected with the supply
line
50 via the distributor piece 8 can be located outside the receptacle 1 in that
case.
The branch sockets 9 branching off from the distribution pipes 7 are
introduced
into the internal space 6 of the receptacle 1 through a receptacle wall in
that case.
The exhaust gas supplied to the branch sockets 9 is charged with a dispersed
scrubbing liquid virtually creating a kind of mist or aerosol out of exhaust
gas and
dispersed scrubbing liquid. In this way, a large surface of scrubbing liquid
is
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_ CA 02753662 2011-08-25
created where the exhaust gas gets into contact with the scrubbing liquid
which
promotes the desired cleaning of the exhaust gas. Charging the exhaust gas
with
dispersed scrubbing liquid can, for example, occur centrally in the area of
the
supply line 50 close to the receptacle, or locally, for example in the area of
the
distribution pipes 7 and/or preferably in the area of the branch sockets 9.
For
central charging of the exhaust gas with dispersed scrubbing liquid, a feeding
device 51 associated with the supply line 50 is proposed in figure 1 which
includes
here one or several spray nozzles 52 for spraying in scrubbing liquid.
The scrubbing liquid can advantageously be water but also salt water or
brackish
water with or without the addition of chemicals. In any case, the scrubbing
liquid is
such that during the entire scrubbing process only little or preferably no
foam at all
occurs.
In the example shown, in addition to the central feeding device 51, also local
feeding devices 51a associated with the branch sockets 9 are provided, with
part
of the scrubbing liquid being introduced by means of the central feeding
device 51
and the remainder by means of the local feeding devices 51a. In the example
shown, spray nozzles 10 located in the upper region of the branch sockets 9
are
associated with the branch sockets 9 which spray nozzles are chargeable with
scrubbing liquid. The spraying direction of the spray nozzles 10 and/or 52 is
coincident with the flow direction of the exhaust gas flowing past so that
virtually a
co-current or parallel flow treatment occurs. For formation of the spray
nozzles 10
and/or 52, pressure spray nozzles can be provided which atomise the scrubbing
liquid supplied into very fine, tiny droplets. The spray nozzles 10 and/or 52
can
perhaps be arranged centrally in the correspondingly associated flow channel,
i.e.
in the branch sockets 9 and/or the supply line 50. But of course it would also
be
possible to provide several spray nozzles each distributed over the cross
section.
The spray nozzle 52 located in the supply line 50 is mounted on an arm 53
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extending into the supply line 50 which can advantageously be formed at the
same
time as a feed line for supplying the associated spray nozzle 52 with biased
scrubbing liquid. The spray nozzles 10 located in the branch sockets 9 are
each
placed at the lower end of an injector 11 interpenetrating the associated
distribution pipe 7 and extending into the upper region of the associated
branch
socket 9 and coaxial to the latter. The injectors 11 are likewise
advantageously
formed as feed lines associated with the nozzles 10 chargeable with biased
scrubbing liquid.
In addition or alternatively to use of atomising nozzles, also by means of a
Venturi
assembly dispersion of scrubbing liquid in the exhaust gas can be achieved.
For
this purpose, the supply pipe 50, as is shown in figure 8, can be provided
with a
flow throttle 54 accelerating the exhaust gas flow which flow throttle is
associated
with a supply device 55 located above the throttle for feeding scrubbing
liquid.
Said supply device 55 can be provided with nozzles or formed without nozzles.
For
formation of the flow throttle 54, the supply line 50 is provided with a
corresponding wall neck-in 56. As a result of the change of direction and
acceleration of the exhaust gas occurring in the area of the flow throttle 54,
a very
good distribution of the scrubbing liquid supplied is obtained.
In a similar way, the pipe sockets forming the branch sockets 9 can each also
be
associated with a Venturi assembly. As is shown in figure 9, the branch
sockets 9
can also be provided with a flow throttle 54 for this purpose which is
associated
with a supply device located above for feeding scrubbing liquid. For formation
of
the supply devices associated with the branch sockets 9, injectors 11 of the
type
already mentioned in connection with figure 1 and provided with a central
supply
duct 57 are used. The injectors 11, however, are not provided with a nozzle 10
here at their lower end. Rather, the supply duct 57 of the injectors 11 is
open at
the bottom. In the example, which is the basis of figure 9, the flow throttle
54 is
formed by a wall neck-in 56 similar to the embodiment according to figure 8.
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, CA 02753662 2011-08-25
An alternative embodiment is shown in figure 10. Here, a flow body 58
preferably
centrally located in the flow channel, here in the branch socket 9, is used
for
formation of a flow throttle 54a. Said flow body has advantageously the form
of a
streamlined arrow directed towards the bottom. By means of the flow body 58
likewise a deflection and acceleration of the exhaust gas flowing past can be
obtained. The flow body 58 can advantageously be mounted at the lower end of
an injector 11 extending into the associated branch socket 9. Said injector is
advantageously provided with outlet ports 59 adjacent to the flow body 58 and
radially extending from its central supply duct 57. In the embodiment
according to
figure 10, the outlet ports 59 are located in the area of the lower end of
injector 11.
Of course, it would also be imaginable to provide the outlet ports 59 in the
area of
the flow body 58. Such an embodiment is shown in figure 11. The supply duct 57
of course extends here up to the outlet ports 59 and into the flow body 58.
Moreover, the embodiment according to figure 11 corresponds to the arrangement
according to figure 10.
The flow body 58 can be formed in one part or several parts. The flow body 58
can
also be formed in one part with the associated injector 51 or attached to it.
The
surface of the flow body 58 can advantageously be provided with a wear
resistant
protective layer which can be a welded-on or melted-on layer. The protective
layer
can advantageously be composed of glass so that a very low flow resistance
occurs. An internal Venturi assembly of the type shown in figures 10 and 11
can of
course also be provided for formation of a central feeding device 51 in the
area of
the supply line 50.
Below the branch sockets 9 at least one sump 12 is located into which the
branch
sockets extend with their lower open ends as can be seen best in figure 2.
Advantageously, an own sump 12 each is allocated to each branch socket 9, with
the sumps 12 allocated to the adjacent branch sockets 9 forming a row of the
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CA 02753662 2011-08-25
above mentioned type being able to be connected into a continuous cassette 13
over the width of the internal space 6. Continuous cassettes 13 in
longitudinal
direction can be provided as well.
One valve body 14 each is allocated to the open lower end of the branch
sockets 9
which valve body can be adequately adjusted. By it, the clearance between the
valve body 14 and the lower end of the associated branch socket 9, and thus
the
available cross-sectional flow area can be adjusted. Adjustment is
advantageously
made such that the exhaust gas volume flow through all branch sockets 9 is
identical. As is best shown in figure 3, the adjustable valve body 14 is
received on
a rod 15 coaxially to the associated branch socket 9 which rod is fixed with
its
upper end on at least one strut 16 attached to the inner wall of the
associated
branch socket 9. Of course, also several struts offset from each other in
height
and/or circumferentially can be provided. The rod 15 can be formed as a
threaded
rod onto which nuts 17 fixing the associated valve body 14 can be screwed by
means of which adjustment of the valve body 14 is possible.
The valve bodies 14 associated with the open lower end of the branch sockets 9
cause a radial flow deflection, i.e. the volume flow arriving in the direction
of the
axis of the branch sockets 9 is distributed radially in all directions. As is
shown in
figure 12, the valve bodies 14 comprise a conoid core 14a the upper side of
which
is formed by a surface of revolution formed by a generatrix bent concavely
towards
the bottom. This results in a curved transition from the axial, here
vertically
extending direction to the radial, here horizontally extending direction. The
upper
side of the core 14a is advantageously occupied with radially extending blades
which are equidistantly spaced from each other in circumferential direction so
that
a uniform distribution around the circumference occurs.
As is shown further in figure 12, the upper edge 61 of the blade 60 extends
starting from the peak of the conoid core 14a horizontally or here slightly
inclined
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towards the outside so that the height of the blades 60 increases from
radially
inside to radially outside. As is shown in figure 13, the blades 60 can be
bent
across their length. In this way, an especially good swirl of the volume flow
deflected into the radial direction can be obtained.
The inert forces imposing on the mass-carrying droplets, which are accelerated
in
radial direction on the deflection caused by the valve body 14, counteract a
change of direction and result here already in a separation of droplets from
the
deflected volume flow. This concerns in particular the heavy droplets. The
separated droplets are virtually absorbed by the circumfluent scrubbing liquid
in
the sump 12.
The sumps 12 are each divided by an intermediate bottom 18 penetrated by each
associated branch socket 9 into a lower compartment 19 into which the
associated
branch socket 9 leads with its lower, open end, and in which the valve body 14
is
located, and into an upper compartment 20. In operation, not only in the lower
compartment 19 but also in the upper compartment 20 scrubbing liquid exists.
Each sump 12 contains accordingly a scrubbing liquid bath split by the
intermediate bottom 18. The intermediate bottom 18 is formed as a gas and
liquid
permeable, extensive retaining element which contains a large number of narrow
passages distributed over its surface between the lower compartment 19 and the
upper compartment 20 and accordingly between the lower and upper part of the
scrubbing liquid bath. For this, the retaining element forming the
intermediate
bottom 18 can be formed as a single or multiple layer grid and/or network of a
close-meshed grid or mesh or wire cloth or expanded metal or as a similar
permeable structural element and/or structural element package assembly, e.g.
out of metal and/or plastic foam. As is further shown in figure 3, the
intermediate
bottom 18 is supported on the border upon sump-fix supporting strips 21 and
fixed
from the top by means of a box or bushing 23 encompassing the associated
branch socket 9 and fixable to it by screws 22.
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Between the intermediate bottom 18 and the supporting strips 21 a spacing
element assembly 21a of adequate height, e.g. in the form of strips resting
upon
the supporting strips 21 or a frame etc. resting upon the supporting strips
21, can
be provided. By means of the spacing element assembly the position of the
intermediate bottom 18 relative to the lower end of the associated branch
socket 9
can be finely adjusted.
In operation, the device according to the invention is charged with exhaust
gas
which can be more or less pressured and which is distributed onto the branch
sockets 9 and flows through all scrubbing stations under the effect of its
inherent
pressure. At the same time the liquid feeding devices 51, 51a are charged with
a
hardly foaming or preferably non-foaming scrubbing liquid, advantageously in
the
form of water, which is dispersed by atomising nozzles and/or Venturi effect
so
that very fine droplets are formed, and a mist and/or aerosol is created in
the end
area of the supply line 50 close to the receptacle and in the branch sockets
9. By
these spray treatments in a first treatment step the solid contaminants
contained in
the exhaust gas, which form condensation nuclei, are captured by the scrubbing
liquid droplets, here the water droplets, and entrained by them. Likewise, the
gases contained in the exhaust gas and removable by scrubbing are removed by
the water droplets and entrained by these.
The volume flow discharged from the branch sockets 9 in the form of the
exhaust
gas-water-mixture and/or aerosol formed is introduced into the scrubbing
liquid
bath contained in the associated sump 1. As can be seen from the flow arrows
in
figure 4, a radical deflection from the vertical direction to the horizontal
direction
results here by the valve body 14, with the scrubbing liquid contained in the
lower
compartment 19 being displaced from the area adjacent to the intermediate
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=
bottom 18 as is suggested in figure 4 by an irregular surface 24.
Simultaneously, a
larger part of the droplets penetrates into the scrubbing liquid contained in
the
lower compartment 19 and is absorbed by it. The exhaust gas with the remainder
of the water droplets is present at the lower side of the retaining element
formed
by the intermediate bottom 18 in the form of a cushion 25 and gets into the
upper
compartment 20 via the fine passages of the retaining element, with the water
droplets still getting through being absorbed by the scrubbing liquid present
there,
and the exhaust gas in the form of fine, small bubbles and/or beads 26
bubbling
towards the top, with residual contaminants still contained in the exhaust gas
being captured by the scrubbing liquid and passing over into it.
For filling the sumps 12 with scrubbing liquid, a feeding device (not shown)
is
advantageously associated with the sumps 12. In operation, the liquid filling
of the
sumps 12 in the form of the scrubbing liquid dispersed in the exhaust gas, is
constantly being replenished resulting in a permanent renewal of the scrubbing
liquid in the sumps 12. The sumps 12 are accordingly provided with a drain
hole
27 on the bottom which is advantageously located at the lowest point in the
inclined sump bottom. The drain hole 27 is dimensioned such that less
scrubbing
liquid can be discharged via it than is being replenished. The excess is
discharged
via the upper edges of the sumps 12, which accordingly form overflow edges 28,
as is shown in figure 4. The scrubbing liquid flowing off from the sumps 12
towards
the bottom and/or flowing over via the overflow edges 28 is collected in the
lower
area of the internal space 6 of the pressure vessel 1 and is flowing off via
the
outlet 4 exiting towards the bottom.
The exhaust gas bubbling through the upper compartment 20 and rising from said
compartment can still entrain particles in the form of contaminants, water
droplets
and the like. In order to remove these particles to a large extent, another
single-
stage or multi-stage separation takes place above the sumps 12. In the example
shown in figure 1, the separation is a single-stage separation. For this
purpose, a
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deflector shield 29 penetrated by the branch sockets 9 with degree of freedom
of
movement is provided, the lateral edges of which form gap-like, lateral flow
passages 30 with the adjacent side walls of the pressure vessel 1. The exhaust
gas rising from the sumps 12 is accordingly led alongside the lower side of
the
deflector shield 29 approximately horizontally and radially towards the
outside and
deflected there, resulting in a separation of mass-carrying particles by the
effect of
centrifugal force. To reinforce deflection, the lateral flanks of the
deflector shield 29
can be bent towards the bottom, as is shown in figure 2. The deflector shield
29 is
advantageously located on the average height of the barrel-type pressure
vessel 1
where the greatest clearance exists, so that the exhaust gas subsequent to the
lateral flow passages 30 mentioned is lead inside again through the wall of
the
pressure vessel 1 which even increases the deflection effect. Due to the
deflection, water droplets entrained by the exhaust gas are centrifuged
radially
outside and are discharged towards the bottom alongside the pressure vessel 1
wall. In order to make sure that no water droplets can be entrained up to the
exhaust gas outlet 3, above the flow passages 30, drop catch strips 31
projecting
from the interior wall surface of the pressure vessel 1 towards the inside are
provided which are advantageously inclined towards the bottom.
In the example shown in figure 8 a two-stage separation above the sumps 12 is
intimated. For this purpose, a separating element 62 made out of a material
permeable for exhaust gas is located upstream of the deflector shield 29. The
separating element 62 can be a plate-shaped element as is shown in the
example,
and is advantageously located in the receptacle 1 without any gaps. For
formation
of the separating element 62, porous and/or crosslinked material can be used
having irregular transit paths for the medium penetrating it so that there is
a high
probability that mass-carrying particles strike against edges etc. and are
thus
captured.
It would also be imaginable to provide a single-stage separation above the
sumps
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CA 02753662 2011-08-25
12 only by using one separating element 62. In that case, the deflector shield
29
provided above the separating element 62 could be omitted. But it would also
be
imaginable to arrange several separating elements 62 one after another with it
being possible that at least one is formed as a deflector shield.
The exhaust gas passing the flow passages 30 flows close to the walls past the
distribution pipes 7 to the exhaust gas outlet 3 which is provided in figure 1
in the
vertex area of the pressure vessel 1. But the exhaust gas outlet can also
occur on
the front as is intimated in figure 8 at 3a. The distribution pipes 7, which
are
charged inside with fresh exhaust gas, can act as heating tubes on which the
exhaust gas flowing past is heated. In order to increase this effect, the
distribution
pipes 7 can be provided with radiators on the outside. The exhaust gas
discharged
via the exhaust gas outlet 3, 3a can either be used for exhaust gas
recirculation
and/or supplied to an exhaust pipe.
Large engines of the type mentioned above are often used as propulsion systems
for ships. Ships lying in the water can tilt laterally, which may also result
in tilting of
the inventive device and in particular the sumps 12, as is intimated in figure
5. If an
own sump 12 is associated with each branch socket 9, as is shown in the
example, there will be many, comparatively small sumps 12 so that even in the
event of a comparatively large tilt, the lower, open end of each branch socket
9
normally is deep enough below the liquid level in the associated sump 12, as
is
clearly shown in figure 5. Insofar as this is no longer guaranteed and/or if
the loss
of scrubbing liquid is too great, the sumps 12 are replenished which is
possible
rapidly and easily by means of the scrubbing liquid feeding device associated
with
the sumps 12.
To simplify the erection, the adjacent sumps associated with a row of branch
sockets 9 located transversely to the receptacle axis, can be combined into a
common cassette 13, as already mentioned above, which cassette is divided into
individual sumps by intermediate walls 32, as is best shown in figure 2. The
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cassettes located one after another in the direction of the receptacle axis
can
advantageously be spaced apart from each other. But it would also be
imaginable
to combine the sumps located one after another in the direction of the
receptacle
axis into common cassettes continuous over the receptacle length and which are
laterally spaced apart from each other. The intermediate walls 32 are in any
case
advantageously provided with overflow orifices 33 in the area between the
upper
side of the intermediate bottom 18 and its upper edge. Via said overflow
orifices a
liquid exchange can occur between adjacent sumps. By this it is guaranteed
that
independent of the liquid replenishment, approximately the same liquid level
is
achieved in all adjacent sumps. The position of the overflow orifices 33 is
selected
such that also in the event of the largest tilt, the intermediate bottom 18
acting as a
retaining element is covered with scrubbing liquid over the entire surface and
accordingly also the open, lower end of the branch sockets 9 is entirely
overflown,
as is clearly shown in figure 5.
As is further shown in figure 3, the cassettes 13 are provided with lateral
support
strips 34 which can be placed upon holding strips 35 provided on the
receptacle.
Advantageously, the support strips 34 and/or holding strips 35 can be located
adjustable in height so that the immersion depth of the branch sockets 9 is
likewise adjustable.
Figures 6 and 7 show application examples of the multi-stage exhaust gas
scrubbing device described above. As already mentioned, a preferred
application
is scrubbing of the exhaust gas used for exhaust gas recirculation, i.e. of
exhaust
gas added again to the fresh charge air supplied to the engine for reduction
of NO),
and/or SON-output of an engine. Such an application is shown in figure 6 where
a
large engine intimated in the form of a cylinder is shown in the form of a two
stroke
large Diesel engine 36. The exhaust connection 37 extending from the working
area of the cylinder and controllable by an exhaust valve opens out into an
exhaust gas header 38 passing via all cylinders. In the bottom area of the
cylinder
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barrel, inlet slots 39 are provided via which charge air is supplied to the
working
area at lowered piston. An exhaust gas turbo charger 40 is associated with the
engine, the turbine of which is operated with exhaust gas and the compressor
of
which supplies the precompressed charge air. Accordingly, the turbine of the
exhaust gas turbo charger 40 is connected with the exhaust gas header 38 via
an
exhaust gas pipe 41. From the compressor outlet a charge air pipe 42 is
leading to
the inlet slots 39. Exhaust gas is added to the charge air. For this purpose,
a
recirculation line 43 branches off from the exhaust gas pipe 41 which opens
out
into the charge air pipe 42 or, as is intimated by means of a dashed line,
into the
intake socket of the compressor of the exhaust gas turbo charger 40. The
exhaust
gas scrubbing device, intimated by the pressure vessel 1, is integrated into
the
recirculation line 43 for scrubbing of the exhaust gas. Here, only that
portion of the
exhaust gas is scrubbed which is used for recirculation.
But it would also be imaginable to scrub the entire exhaust gas prior to
emission
into the environment. Such an embodiment is shown in figure 7. Here, the
exhaust
gas scrubbing device intimated by the pressure vessel 1 is built into an
exhaust
pipe 44 extending from the turbine outlet of the exhaust gas turbo charger 40
and
opening out into the environment. Moreover, the engine layout corresponds to
the
arrangement of figure 6.
In the examples shown in figures 6 and 7 an individual, own, inventive device
for
exhaust gas scrubbing is each associated with each internal combustion engine.
But it would also be imaginable to associate one common inventive device for
exhaust gas scrubbing with an arrangement of several internal combustion
engines. Likewise it would be imaginable to associate several inventive
devices for
exhaust gas scrubbing with one internal combustion engine. Another possibility
is
to use the scrubbed exhaust gas contrary to the embodiments of figures 6 and 7
only partly for exhaust gas recirculation and to discharge the remainder as
exhaust
gas. This applies not only to assemblies installed aboard a ship but also to
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stationary assemblies.
Some embodiments and application examples are explained above in detail which
are, however, non-limitative. Rather, a number of possibilities are available
to the
person skilled in the art in order to adapt the invention to the conditions of
an
individual case.
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