Note: Descriptions are shown in the official language in which they were submitted.
21 ~'~~~3
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The invention relates to an apparatus for removing
undesired components from a fluid, particularly an
exhaust gas, with a reactor which defines at least one
reaction space which has supply means at its top and
hopper-shaped outlet means at its bottom for supplying
and for discharging, respectively, a pourable,
particulate or granular adsorption agent.
DE-A 2626939 shows an apparatus of the above type in
which the fluid is guided within the reaction space
through two layers moving parallel to one another and the
adsorption agent in the downstream layer is moved at a
higher speed and is loaded to a lesser extent than in the
layer on the upstream side. As complete as possible a
cleaning of the exhaust gas is supposed to be effected
with this known apparatus since sufficient fresh
adsorbent is available to the exhaust gas on the
downstream side. On the other hand, adsorbent, which is
utilised only to a very limited extent, must be
continuously withdrawn in a relatively thick layer on the
downstream side and regenerated. The reaction chamber is
divided by vertical partition walls. The individual
sections are supplied from a central filling opening with
adsorption agent and have outlet openings or hoppers
associated with the individual layers.
It is known from DE-C 3427905 to make the adsorbent
particle flow uniform over the cross-section of the
moving bed by means of installations.
In known adsorption apparatus, substantial portions,
particularly of the loose material cone in the top region
and of the outlet cone in the bottom ~eg'~.on of the
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reactor can not be reached, or only unsatisfactorily, by
the transversely flowing fluid. The consequence is hot
spots (thermal concentrations) up to furnace temperatures
in the top region and the accumulation of condensate in
conjunction with the agglomeration of particles in the
bottom region of the reactor.
The degree of efficiency of the gas cleaning in such
moving bed reactors, which operate continuously or quasi-
continuously, also depends on the unimpeded and uniform
replacement of the charged adsorption agent particles by
fresh and reactive particles. Fresh solid particles are
introduced from above into the reactor in the amount in
which charged loose material particles are discharged at
the bottom out of the delivery openings after passing
. through the reactor and reacting with the fluid to be
cleaned. The discharge by means of rotating dosing
apparatus has not proved to be satisfactory due to the
aggressiveness of the discharged materials and the non-
uniform particle size and shape of the adsorption agent.
It is the object of the invention to ensure that the
fluid to be treated flows better through the adsorption
agent bed and to prevent operational disruptions,
particularly in the critical top and discharge regions of
the adsorber.
In order to solve this obj ect the apparatus in accordance
with the invention is characterised in that the supply
means are constituted by a grid of a plurality of supply
hoppers arranged adjacent and behind one another and the
outlet means are constituted by a further grid of outlet
hoppers with delivery openings and arranged adjacent and
behind one another; that fluid openings are provided not
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only on at least one side but also in the top region of
the reaction space; that arranged beneath the delivery
openings there is a substantially horizontal intermediate
storage plate with discharge openings situated laterally
adjacent the delivery openings; and that a discharge
rake, whose blades engage in the space between the
delivery openings and the intermediate storage plate, is
swingably suspended on at least one support axis such
that adsorption agent piled up beneath the delivery
openings is slidable transverse to the pouring direction
into the lateral discharge openings.
By dividing the supply and discharge regions of the
adsorption agent into a plurality of conical sub regions,
the pockets of material in the top and bottom regions of
the reactor which are difficult to be reached by the
fluid flow are minimised. Furthermore, the particle flow
and loose material mechanics within the reaction space
are improved, not only in the supply but also in the
discharge of the adsorption agent, by the division into
component flows. Although the main flow of the fluid is
directed transverse to the adsorption agent column, fresh
adsorber in the top region of the reactor is caused to
participate in the reaction to an enhanced extent by the
fluid introduced there into the reaction space or
discharged out of the reaction space.
A further substantial advantage of the invention resides
in that the discharge rake manages without linear guides
which are at risk of clogging. The oscillating bearings
can be arranged substantially above the delivery openings
remote from the regions which are particularly at risk
from dust and granulate and on the other hand can be so
encapsulated that penetration of dust or abraded
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particles is substantially prevented. The horizontal
movements of the oscillating or swinging suspended rake
are sufficiently large in order to move the loose
material cone piled up under each delivery opening to one
or other side into the discharge openings on each
movement back and forth of the rake. The vertical
movements of the operational blades, which are of small
stroke by comparison, loosen the loose material cone and
reduce the pushing forces necessary to tranport the loose
material in comparison to purely horizontal linear
movements. Sliding contact between the discharge rake or
its blades and the fixed components of the discharge
occurs - if at all - only to a small extent and
indirectly via the solid particles to be discharged.
A particularly precise horizontal guiding of the
discharge rake without the guide components engaging in
one another may be achieved in a further embodiment of
the invention if the discharge rake is suspended on an
oscillating parallelogram, all the pivotal axes lying in
a common horizontal plane which is preferably arranged
spaced above the discharge openings. With this type of
oscillating suspension, the blade angles remain constant
in each phase of movement and can accordingly be preset
to the optimum degree of blade efficiency during both the
forward and the backward movement.
In the adsorption apparatus in accordance with the
invention the delivery openings are arranged in the
manner of a grid or matrix in columns and rows. A
discharge rake can be associated with a plurality of
delivery openings arranged in a plane and behind one
another in at least one row. This reduces the expense
for the associated actuator or actuators.
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A plurality of rectangular intermediate plate sections
and delivery openings are preferably arranged behind one
another in the direction of movement of the rake. After
movement of the blades within the gap the loose material
piles up again beneath each delivery opening and is
discharged during the rearward movement into the
discharge opening situated on the other side of the
intermediate storage plate section.
In the preferred embodiment the discharge rake comprises
a frame into which walls acting as plates are inserted.
The drive for the discharge rake is derived in the
preferred embodiment of the invention from at least one
crank mechanism. The crank mechanism enables the precise
' adjustment of a horizontal movement stroke without
impairment by (small) vertical movements superimposed on
it. A plurality of discharge rakes can be actuable in
different movement cycles and/or in offset phases. A
plurality of ajacent reaction chambers or chamber regions
can thus be operated with different bed movement speeds
or different exchange volumes in order to adapt the loose
material discharge to the reaction conditions in all the
reactor regions as optimally as possible.
The carrier components and their mounting can vary with
the respect~.ve conditions of use. Thus the discharge
rake can be suspended, for instance, on the discharge
plate or on an independent frame.
Further details of the invention will be apparent from
the following description of exemplary embodiments which
are schematically illustrated in the drawings. Sub-
combinations of the features of the claims are also
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disclosed as being of importance to the invention.
In the drawings:
Fig. 1 is a vertical sectional view through an adsorption
device in accordance with the invention without a
discharge device;
Fig. 2 is a side view of the lower portion of Fig. 1 with
an exemplary embodiment of the new discharge device, seen
transverse to the direction of movement of the moved
parts of the discharge device;
Fig. 3 is a vertical view at right-angles to Fig. 2;
Fig. 4 is a scrap view in which an alternative suspension
of the discharge rake to that of the embadiment of Fig.
3 is shown.
The adsorber 1 illustrated in vertical section in Fig. 1
has a crude gas inlet 2 and a clean gas outlet 3.
Between the inlet and outlet the fluid f lows through a
first reaction stage 4 and a second reaction stage which
is divided into two reaction chambers which are connected
in parallel and situated in front of and behind the plane
of the drawing. The reaction stage 4 has a reaction
chamber 14 of rectangular cross-section which is filled
in operation with a bed of loose material of particulate
or granular adsorption agent. The chamber 14 is bounded
on the inlet side by a shutter 15 extending over the
entire height of the chamber and on the outlet side by a
shutter 16 which extends only up to a limited height.
The supply of the adsorption agent is effected from a
supply container 7 positioned on the chamber 14 via a
distributor plate 8 at the top. The distributor plate
comprises a uniform grid in the illustrated exemplary
embodiment of square supply hoppers 18 which are arranged
adjacent one another and behind one another in rows and
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columns and connected to which are supply tubes 19
opening out into the chamber 14.
An intermediate plate 8a is installed approximately half
way up the chamber 14. It serves principally to relieve
the pressure in high adsorption beds and in the
illustrated exemplary embodiment has the same
construction and arrangement (grid of supply hoppers 18a
and supply tubes 19a and blocking section 30a) as the
distributor plate 8. The guiding of the fluid through the
loose material core below the intermediate plate 8a also
corresponds to that in the top region. The incorporation
of one or more intermediate plates 8a into the reaction
chamber is not necessary but frequently convenient.
An outlet plate 9 is composed similarly to the
distributor plate 8 of a grid of outlet hoppers 20
arranged adjacent one another and behind one another.
Connected to the outlet hoppers 20 are outlet tubes 21.
The crude gas inlet 2 broadens out to the dimension of
the entire height of the reaction chamber 14, that is to
say to the region of the supply hoppers 18 and supply
tubes 19. The fluid can thus flow into the adsorption
agent bed not only from the side through the shutter 15
but also from above between the supply tubes 19 through
the loose material cones 37, as is shown by the solid
line arrows A in Fig. 1. The fluid can thus reach all
the zones of the loose material bed, not only with a
shifting bed but also with a stationary bed. Thus
practically all the particles take part in the reaction
in the same manner.
E1
8.
Provided on the outlet side between the uppermost layer
(loose material cones 37) and the upper end of the
downstream shutter 16 is a blocking section in the form
of a closed wall 30 which prevents a short circuit of the
fluid from above directly into the outlet channel 31.
The outlet passage 31 merges into a horizontal passage
section 32 which extends beneath the outlet plate 9. The
precleaned fluid leaving the reaction chamber 14 through
the outlet passage 31 flows around the outlet hoppers 20
and the outlet tubes 21 in the passage section 32 and
thus heats the adsorption agent situated within these
elements to the extent that condensation is reliably
prevented. The fluid is deflected upwardly out of the
passage section 32 into the two chambers of the second
reaction stage. The fluid distribution in the two
chambers essentially corresponds to the fluid
distribution described above at the shutter 15 on the
inlet side and the loose material cones 37 at the top of
the first reaction stage 4. Supply and outlet hoppers
are also arranged in the manner of grids in the two
chambers in order to ensure as uniform as possible
participation of the adsorption agent in the entire
interior of the chambers.
As may be seen in Fig. 1, the reducing agent NH3 is
injected in at the deflection point between the outlet
passage 31 and the horizontal passage section 32. Other
supply points or preloading of the mineral coal activated
coke in the chambers of the second reaction zone are of
course also possible.
As regards the shapes and dimensions of the individual
hoppers 18 and 20, the invention is not subject to any
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special exceptional conditions. A square or optionally
rectangular crass-sectional shape ensures a particularly
large area utilisation of the cross-sectional surface in
the loose material distribution and favourable loose
material mechanics. Other shapes are, however, possible
essentially with the same advantages of the invention.
The crude gas inlet 2 can, however, also extend to below
the outlet plate 9, whereby suitable openings to the
interior of the reaction chamber 14 are then formed in
the outlet hoppers 20, through which openings the crude
gas can flow in but no granular adsorption agent can flow
out into the fluid inlet distributor. Such incident flow
plates are known, for instance, from DE-G 8706839.8.
When constructing the outlet plate 9 as an incident flow
plate a blocking section corresponding to the wall 30
must also be provided at the rear wall directly above the
plate 9 in order to prevent fluid short circuits to the
outlet passage.
In the view of Figs. 2 and 3 15 outlet hoppers 20 are
arranged in the discharge plate 9 in a matrix of five
columns in three rows. Each outlet hopper 20 opens out
into the associated vertically extending outlet tube 21.
All the outlet tubes have delivery openings 33 arranged
in a common horizontal plane.
Arranged spaced below the delivery openings is an
intermediate storage plate 34 which has a plurality of
rectangular sections 35 lying in a common horizontal
plane. Provided on both sides of each section 35 of the
intermediate storage plate 34 are discharge openings 36
which open out into a discharge hopper 37 extending over
the entire reactor base.
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The discharge device described below may be used with
essentially the same advantages on counterflow,
transverse flow and even co-flow reactors and on all
apparatus in which pourable solid materials are to be
discharged in a dosed manner from a reaction space or
other storage space.
Schematically illustrated in Fig. 2 below the delivery
openings 33 are loose material cones 38 which, in
operation, are heaped up above each section 35 of the
intermediate storage plate 34 before they are discharged.
The discharge device has a discharge rake 39 which
comprises a rectangular frame 40 and blades 41 arranged
in it in the manner of cross bars. The rake is so
dimensioned that it can be moved with the blades 41 in
the transversely extending frame sides without contact in
the gap between the intermediate storage plate 34 and the
lower edges of the outlet tubes 21 surrounding the
delivery openings 33. The loose material cones 38 can be
limited by the blades 41 and the transversely extending
sides of the frame 40. The rake 39 is suspended on
pivotal arms 42 constituting an oscillating parallelogram
such that its frame 40 extends parallel in every pivotal
position of the oscillating parallelogram. The pivotal
' arms 42 have stationary bearing points at the upper end
whose axes 43 lie parallel to one another in a common
horizontal plane. In the ~ exemplary embodiment
illustrated in Figs. 2 and 3, the bearing points are
arranged below the outlet plate 9 on reactor support
constructions 45. Alternatively, the pivotal arms 42 can
also be arranged on individual support bridges 46 (Fig.
4) .
The motor 47 in combination with a crank assembly 48
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serves as the actuator for the discharge device. The
crank assembly 48 has a connecting rod 49 which is
pivotally connected to one side of the discharge rake 39
and actuates the discharge rake 39 in the direction of
the double headed arrow A in Fig. 2. A gentle vertical
movement is superimposed on the movement in the
horizontal principal direction A due to the oscillatory
support of the rake 39, but this is small in comparison
to the horizontal transport movement in the direction of
the arrow A. The greater the distance between the pivot
points 43 and 50 of the pivotal arms 42 the smaller it
is. The slight vertical movement is however definitely
operationally desirable; thus whilst sweeping over the
sections 35 it imparts an additional rotation or rolling
movement to the particulate, pulverulent or granular
loose material due to the blades 41 of the discharge rake
39 and thus breaks up lumps. Intensified breaking up of
agglomerated loose material may be achieved by means of
rods, tines, bevelled projections, ribs, noses or the
like 41a which are arranged in front of the active blade
surfaces of the discharge rake 39 and break up the loose
material in the manner of a rake or ploughshare. The
movement stroke in the direction of the double headed
arrow A is selected to be so large that each loose
material cone is discharged at least during one movement
stroke in one direction into one of the adjacent
discharge openings 36. Preferably, however, the
arrangement of the blades 41 and of the transversely
extending sides of the frame 40 is such that transport of
a loose material cone 38 into one of the two adjacent
discharge openings 36 and removal through the discharge
hoppers 37 occurs in each direction of movement.
As stated above, it is of no significance to the
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kinematics and the transfer capacity of the discharge
device illustrated in Figs. 2 and 3 at which horizontal
positions the bearing points 43 are arranged. Of
importance are the horizontal oscillatory amplitude and
the arrangement or the layout grid of the blades 41
and/or the frame sides. This layout grid is so selected
in the exemplary embodiment shown in Fig. 2 that in the
right hand end position (Fig. 2) of the rake 39 the right
hand most blade 41 has dumped the loose material cone 38
piled up below the first discharge passage into the
discharge opening 36 furthest to the right; in the
opposite swinging movement of the rake 39 or the pivotal
arms 42 to the furthermost position on the left, the same
blade 4I has pushed the loose material cone which has in
the meantime built up below the right hand most delivery
opening 33 above the right hand section 35 into the
region of the left hand discharge opening 36 and pushes
it into this discharge opening 36. The blade 41 has thus
reached its lowest vertical position in that pivotal
position of the rake 39 in which it is disposed axially
below the delivery opening 33. The blades 41 and the
transversely extending sides of the frame 40 (Fig. 2,
left and right) can also be used to limit and adjust the
cone of loose material 38. For this purpose the
distances between adj acent blades 41 must be smaller than
the breadth in the direction A of each intermediate
storage plate section 35. Furthermore, the rake must be
halted after each discharge stroke in a suitable position
in which the blades are centred in pairs on the axes of
the delivery openings 33 so that sintered loose material
cones 38 can form.
The entire matrix of outlet tubes 21 and delivery
openings 33 arranged in rows and columns is made use of
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in the described exemplary embodiment of a rectangular
discharge rake 39. The blades 41, inserted in the manner
of cross bars, are rigidly coupled from row to row, i.e.
in the direction of the gaps, by transverse elements 51.
These transverse couplers 51 can however be omitted and
the rakes 39 which are then produced and service the
individual rows can be actuated with a phase difference
and/or even with different speeds. Also suitable for
this purpose is a crank arrangement whose connecting rods
are pivotally connected to a common crank disc,
optionally with different spacings and/or at different
angular spacings.
The oscillating suspension of the discharge rake 39
described above is useable practically universally. The
' delivery openings 33 certainly do not need to lie at a
common horizontal level, as in the exemplary embodiment
illustrated in the drawings; each blade 4l acting between
a delivery opening 33 and section 35 of the intermediate
storage plate can be moved on a different level of
movement corresponding to the position, size and
construction of the associated loose material cone and at
a completely different angle of incidence from blade to
blade. There are also absolutely no limitations as
regards the number and/or the position of the delivery
openings 33 and intermediate storage plate sections 35 to
be serviced by a discharge rake 39. Parameters of this
type may be freely selected in the invention by the
constructor from case to case. By suitably choosing the
length of the pivotal arms 42 the ratio of the horizontal
to the vertical stroke can also be adjusted. As may be
seen, only simple pivotal bearings 43, 50 are necessary to
retain and guide the moved components of the discharge
device which are insensitive to the heavy dust and
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granulate loading at the place of use.
