EP0215075A1

EP0215075A1 - Cyclone separator with two separator chambers and static guide devices.

Info

Publication number: EP0215075A1
Application number: EP86901811A
Authority: EP
Inventors: Siegbert Schulz
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-03-19
Filing date: 1986-03-19
Publication date: 1987-03-25
Also published as: EP0215075B1; DE3663890D1; US4789476A; WO1986005417A1

Abstract

Dans un séparateur à cyclone avec deux chambres de séparation et des dispositifs statiques de guidage, une colonne à tube plongeur (5, 6, 7), agencée au centre du tourbillon du cyclone conventionnel, entoure l'axe (1) du cyclone sur toute la hauteur h de la chambre de séparation et traverse le récipient collecteur conventionnel (2a) de solides. Cette colonne, en combinaison avec un dispositif (4) d'évacuation de solides sans reflux, stabilise le tourbillonnement intérieur concentré à l'intérieur de la colonne à tube plongeur, dans la deuxième chambre de séparation (3b). En cas de fort tourbillonnement, il se produit ainsi un processus subsidiaire de séparation avec des reflux axiaux (18) allant du tube de tourbillonnement (17) à un deuxième récipient collecteur (2b) de solides. Les composants de la colonne à tube plongeur sont le tube plongeur conventionnel (5), prolongé axialement vers le bas par un tube plongeur de séparation (6) à fentes, et un tube plongeur central (6) monté sous le tube plongeur de séparation (6) et fixé par des flasques au deuxième récipient collecteur de solides. Le tube plongeur de séparation (6) a un effet aspirateur, sert de dispositif de guidage de l'alimentation du tube de tourbillonnement (17) et présente quatre conduites d'admission (10) recourbées, à parois parallèles, uniformément distribuées autour de la circonférence du tube plongeur, ayant chacune un bord droit d'admission (9) et qui exercent un effet accélérateur sur le courant. La récupération de l'énergie cinétique du tourbillonnement se fait par une spirale de décharge (8) en haut du couvercle (13) du cyclone.In a cyclone separator with two separation chambers and static guiding devices, a dip tube column (5, 6, 7), arranged in the center of the vortex of the conventional cyclone, surrounds the axis (1) of the cyclone over its entire length. the height h of the separation chamber and passes through the conventional collection vessel (2a) for solids. This column, in combination with a device (4) for discharging solids without reflux, stabilizes the internal vortex concentrated inside the dip tube column, in the second separation chamber (3b). In the event of strong swirling, a subsidiary separation process takes place with axial refluxes (18) from the swirl tube (17) to a second collecting vessel (2b) for solids. The components of the dip tube column are the conventional dip tube (5), extended axially downward by a slotted separation dip tube (6), and a central dip tube (6) mounted below the separation dip tube ( 6) and fixed by flanges to the second solids collection container. The separating dip tube (6) has a suction effect, serves as a feed guide device for the swirl tube (17) and has four curved, parallel-walled inlet pipes (10) evenly distributed around the tube. circumference of the dip tube, each having a straight inlet edge (9) and which exert an accelerating effect on the current. The kinetic energy of the swirl is recovered by a discharge spiral (8) at the top of the cover (13) of the cyclone.

Description

Cyclone separator with two separation spaces and static

L ed devices

The invention relates to a cyclone separator with two separating spaces and static guide devices for improving the separating capacity with regard to finely dispersed particles from flowing gases and for reducing the pressure loss or for influencing the flow field of a conventional centrifugal separator with tangential, spiral or helical inlet channel , with a top cylindrical and bottom conical cyclone housing, as well as a solids collection container underneath, where / in the cylindrical separating chamber, a cylindrical immersion tube protrudes centrally into the cyclone housing from above to discharge the clean gas flow.

The incoming material is separated in a centrifugal separator due to the centrifugal forces occurring in a swirl flow, which act on the particles flowing on circular or spiral paths. As a result of an axial velocity component of the flow field, the separated coarse material slides spirally on the outer wall of the cyclone into the solids collection container, which forms the lower end of the cyclone housing. The non-separated fine material reaches the clean gas channel with the gas stream emerging through the immersion tube.

l / G As is known, the simple construction of a conventional centrifugal separator ensures high operational reliability, low maintenance, low purchase costs and a small space requirement. The limits of its wide range of application are at an operating pressure of 100 bar and gas temperatures of over 1000 ° C.

The technical advantages of a conventional cyclone are offset by the disadvantages of the high pressure drop and the low separation capacity with regard to the selectivity compared to other separators. The known conventional cyclones, as the main cause of the low separating capacity, show an irregular axial speed distribution along the separating surface, secondary flows, short-circuit flows and strong turbulence within the separating space. The main cause of the high pressure loss is the failure to convert the rotational energy required for separation into pressure energy, as a result of deflection losses and throttling action at the dip tube inlet, so that up to 90% of the total pressure loss in the vortex core (cyclone eye) occurs below the dip tube.

Due to the demand for limiting emissions of respirable dust, recovery of valuable products or maximum separation of abrasion dust from process gases and also for energy reasons, the conventional cyclone must therefore be increasingly combined with other separation apparatuses that are below 20 in the finely dispersed particle size range μm are more powerful. These requirements and the fact that the cyclone for dedusting hot gases above 500 ° C. is the only separator that can be used on an industrial scale require additional structural measures to improve the separating capacity and to reduce the pressure loss.

To meet these requirements, it is known to install guide devices in the separating space or within the immersion tube, although the patent applications published to date do not take into account all the causes of the low separating capacity and high pressure loss and no new cyclone development has a second separating space constructively implemented within a single apparatus and additionally makes backflows around the cyclone axis usable for particle separation.

As a known cyclone version (DE-OS 23 61 995), the cylindrical, conventional immersion tube has, in addition to its axial opening on the lower end face, additionally slotted gas inlet openings in the immersion tube jacket, which are formed by pressed-in tabs of the immersion tube jacket. The effectiveness of the dedusting cannot be promoted, since this slotted immersion tube design has the essential disadvantage that neither the strong sink flow below the immersion tube nor the solid layer flow along the outer surface of the immersion tube is reduced, and no devices for a downstream solids removal. divorce are provided. Devices for the recovery of the kinetic energy are also not available.

A cyclone with a slotted immersion tube is also known (EP-OS 0 0 1 106) which, although utilizing the effect of a double separation within a single apparatus, does not collect the solid matter additionally separated within the immersion tube in a second separation space meln. A slotted conventional immersion tube with an axial outlet gap enables the return of fine material that has already been discharged and enriched on the inner wall of the immersion tube to the separating chamber of the cyclone due to the suction effect from the environment due to a gap that is arranged between the inlet channel and the immersion tube. Further disadvantages of this cyclone design are both the still existing axially non-uniformly distributed sink flow below the immersion tube and the suction of ambient air into the separation process, which increases the pressure loss.

Furthermore, slotted immersion tubes are published in the journals Chem.-Techn. 22 (1970) No. 9, p. 525/532 and mechanical engineering 7 (1958) No. 8, p. 4i6 / _? I. However, these immersion tube designs are only longitudinal slots that are evenly arranged on the circumference of the immersion tube and not upright gap channels that cause flow deflection or energy recovery. By Prof. Dr.-lng. Schmidt is presented with a slotted gap immersion tube (dust-clean air 45 (1985), No. 4, pp. 163/165 and DE-OS 32 23 374) with a helical inlet gap and a three-dimensional diffuser channel Has deflection properties. This so-called screw diffuser is closed on the lower end face by a base plate and is arranged below a conventional immersion tube. This slotted dip tube reduces the pressure loss of a cyclone separator by up to 50% and improves the separating capacity of a cyclone, since there is a transition from the circular hole sink flow to the line sink flow. However, this newly developed dip tube, as a stand-alone design measure, cannot prevent the short-circuit and secondary flows and does not allow the solid matter that is separated inside the dip tube to be removed. As a result of the diffuser channel built into the immersion tube, a critical swirl flow with reverse flows cannot be achieved.

The invention is therefore based on the object while avoiding the be¬ described deficiencies of conventional cyclones in general and the deficiencies of known cyclone improved versions with double deposition duπg and verόesserten ^{'Absaugbedingungen} in particular, form a Zyklonab¬ separator of the type mentioned constructive so, that it is characterized by a greatly improved overall separation rate and fraction separation rate with a simple basic construction and additional installations of static, that is, non-rotating guide and separation devices, so that the selectivity of the cyclone separator is significantly improved, the pressure loss compared to that also being improved conventional execution reduced.

This object is achieved according to the invention in that an immersion tube column consisting of the series connection of a conventional immersion tube, a slotted gap immersion tube with a helical or straight gap channel and a central immersion tube which surrounds the cyclone axis over the entire height of the separating chamber, lies in the cylindrical separating surface of the conventional cyclone separator, penetrates the conventional solids collection container and is gas-tightly connected to a second solids collection container below the first, with each of the three submersible tubes being open at the upper and lower end faces and the gap-immersion tube being the only suction Dip tube is. The inventor accordingly proposes to provide the immersion tube column as a second cyclone within the actual cyclone, so that a two-stage separation is effected in this way in a single dedusting apparatus, although in comparison to the external separation process the mass exchange within the swirl tube by energy transfer via the around the cyclone axis specifying vortex core and reverse flows cause the solids to be transported into the secondary solids collection container below the central immersion pipe if there is a supercritical swirl flow within the swirl pipe.

In the development of the cyclone separator according to the invention, it should be noted in principle that the axial flow directed downward on the outer jacket of the cyclone in the outer flow field of the dratl flow causes the good discharge behavior of the solid in combination with the boundary layer flow on the cone wall. To realize an axial speed component, the gap immersion tube must therefore be arranged below the cyclone inlet channel.

The slotted gap immersion tube is installed centrally between the conventional immersion tube and the central immersion tube in the cylindrical and not in the conical part of the cyclone housing in order to reduce secondary flows from the separating wall of the cyclone jacket. The gap immersion tube enables the transition from the hole sink which is otherwise present below a conventional immersion tube with an uneven axial distribution of the radial speed to the line sink with a uniform axial distribution of the radial speed at the separating surface. The invention is based on the knowledge that the vortex sink flow in the outer separation space is not disturbed or the flow turbulence in the separation space is reduced by a gap channel with a helical inlet edge or by a plurality of screw-shaped gap channels with a straight inlet edge within the gap immersion tube are adorned and the volume flow of the gas is sucked in at high speed through a curved inlet channel adapted to the streamlines with an accelerating effect on the flow axially uniformly above the inlet edge from the outer separating space, so that on the one hand a smoothed speed profile along the adjusts the suction gap, on the other hand the dust particles still present in the gas stream are concentrated in the dead water core around the cyclone axis as a result of pressure forces and are discharged with the aid of backflows into the secondary solids collection container, as a result of which the separated coarse material fraction of the feed material increases, which improves ¬ tion of the total and fraction separation corresponds.

To stabilize the two-stage separation process, the immersion tube column is arranged around the cyclone axis in the vortex core of the conventional cyclone in such a way that it penetrates the outer cylindrical and conical separation space, the cylindrical shielding container and the primary solid collecting container.

A baffle is preferably installed between the inlet channel and the gap immersion pipe below the cyclone inlet channel in the horizontal plane parallel to the cyclone cover in the outer separating space in such a way that short-circuit currents of the swirl flow are prevented directly into the suction gap channel of the gap immersion pipe and the axial velocity component of the swirl flow in the outer separation space is positively influenced with regard to the solids discharge behavior. A tearing off of the cyclone inlet flow at the leading edge of the cylindrical cyclone jacket is thus prevented, whereby at the same time the starting positions of the particles suspended in the entering gas stream are more clearly defined. The baffle thus enables a more even inflow into the gap channel of the gap immersion tube.

The gap immersion tube, which is connected into the immersion tube column between the conventional immersion tube and the central immersion tube, can be provided with four parallei-walled inlet channels evenly distributed on the circumference of the immersion tube, each with a straight entry edge, so that the joint The diagonal of the four recessed surfaces offset by 90 ° forms a single screw line around the gap immersion tube, and the respective curved gap channel in the gap immersion tube is provided as an inlet channel with accelerating flow effect for a swirl tube symmetrical to the cyclone axis, whereby inside the swirl tube a dead water area with axial backflows into the central immersion tube with a correspondingly high swirl strength, which is determined by the geometric design of the gap channel and the gap immersion tube, and wherein high negative pressure values on the cyclone axis and strong pressure changes in the axial direction the intensive backflow in induce the central immersion tube and then into the secondary solids collection container.

The advantages achieved by the invention are, in particular, that this immersion tube column, which fixes the separating surface between the vortex field and the vortex core, or this static guiding and separating device of the rigid body vortex (cyclone eye) of the conventional cyclone further inwards about the cyclone axis Swirl tube axis is concentrated. This rigid body per vortex builds up a secondary swirl field, which is the prerequisite for maintaining the secondary deposition process within the swirl tube.

The slotted gap dip tube acts as a guide device that the swirl generated in the cyclone inlet is reinforced in the center of the swirl tube. This internal swirl flow around the swirl pipe axis results in a dead water around the swirl pipe axis, the radius R of which increases with increasing swirl and in which the particles are “caught”. R. therefore designates the boundary between lossless healthy flow in the area _. r <R and lossy core flow in the area R "r ^" 0. There is a strong negative pressure in the dead water area, so that the particles are transported in the direction of the compressive force to the cyclone axis and do not flow in the direction of the centrifugal force to the swirl tube wall, as is the case in the outer separation chamber is case a large R -. favors the secondary separation effect, since no flow stream within the Totwasserkerns NaCN axially upon generation of a critical swirl flow powers up, which would entrain the particles but a negative flow stream to the Zyklonac ^'HSE particularly within the slit immersion tube provided is.

In the second solids collection container, which is flanged to the central immersion tube and is arranged below the first solids collection container, the additionally separated solids, which are collected with the help of backflows via the central immersion tube as' additional coarse material is transported downwards and would otherwise have flowed out as fine material via the conventional immersion tube in the case of a conventional cyclone design. The dip tube column surrounding the swirl tube additionally stabilizes the three-dimensional turbulent flow field in the outer separation chamber, so that the cyclone axis is identical to the center of the outer swirl flow. The center of the inner swirl flow is the swirl pipe axis, which is congruent with the cyclone axis and which only coincides with the cyclone axis in the case of a symmetrical inflow from the gap immersion tube.

In another embodiment of the invention, in order to increase the rotational symmetry and the swirl strength, the gap-immersion tube with four inlet channels distributed in a screw shape on the circumference of the immersion tube can be replaced by a gap-immersion tube which either has several on the circumference of the immersion tube in the same axial direction Height evenly distributed gap channels are provided with a straight entry edge, or replaced by a gap immersion tube with a parallel-walled screw-shaped gap channel, which has a screw-shaped entry edge and a screw-shaped exit keel, which also produces a supercritical swirl strength with backflows into the central immersion tube , if the respective gap channel is designed as a curved deflecting channel with an accelerating effect and the respective gap channel is provided with an upper and lower cover plate, so that the suction from the outer separating space is provided exclusively via a aube-shaped gap channel or over several edged gap channels evenly distributed around the circumference of the dip tube.

In any case, the curved gap channels within the gap immersion tube serve as inlet channels for the swirl tube arranged symmetrically to the cyclone axis within the immersion tube column, the swirl tube itself preferably being designed as a flow-guiding inlet guide device for an outlet spiral housing with a recessed core arranged above the cyclone cover. The kinetic energy of the outer swirl flow and the inner swirl flow which is in the same direction can be recovered by a wide outlet spiral to be designed in a known manner, the outlet connection of which flows into the clean gas duct and its hub waste water. This area can be filled within an expanded conventional dip tube by a corresponding recess. Advantageously, the inlet opening of the parallel-walled gap channel is designed as a slotted opening within the gap immersion tube jacket in such a way that the required flow velocity at the separating surface in the inlet area of the gap channel corresponds to the existing rotary flow, which in turn is caused by the Course of the gap immersion tube circumference as a logarithmic spiral flow-favorably at the parting surface. r. before tapping, so that the curved streamlines of the gas flow entering the swirl tube through the gap channel run along the outer and inner gap channel contour and in the same direction as the cyclone inlet flow.

, - According to a further embodiment of the invention, a cylindrical shielding container is interposed between the conical part of the outer separating chamber and conventional solids collection such that the outer swirl flow on a lstück designed as shielding cone outer Tei ^'of the central immersion tube within the primary fixed

"S fabric collection container. escapes, whereby the separated solid can penetrate into the primary solid collecting container without disturbing effects in the annular gap between the cylindrical shielding container and the central immersion tube and the solid through the arrangement of a cone-shaped deflector screen below the cylindrical shielding container

" _C and around the shielding cone cannot be whirled back into the outer separator chamber.

The central immersion tube also enables the swirl flow in the outer separation chamber to be separated from the easily circulating one on the pressure side

" ₀ flow in the first solids collection container, in that the shielding cone is installed inside the solids collection container in such a way that penetration of the separated solids into the separation space is prevented, and at the same time the penetration of the separated solids through an annular gap-shaped discharge opening between the cylindrical shielding bed ₅ container and central immersion tube is guaranteed. This discharge device according to the invention accordingly prevents both re-advertising. tion as well as entrainment of already separated particles.

According to the additional embodiment of the invention, the new development of the solids discharge device has the effect that the undesired solids transport of already separated particles from the first dust collection container into the conical outer separating space is completely avoided and that on the conical outer surface of the outer separating space is spiral particles sliding downwards can be transported to the first solids collection tank without disturbance, without penetrating turbulent flow areas with backflows that would cause re-inflation.

As will be shown below with the aid of measurement curves, the design of the cyclone separator according to the invention results in an increase in the overall degree of separation and in the fractional separation with a simultaneous reduction in the pressure loss compared to the conventional cyclone design. In particular, the diameter of the smallest particles, which are separated by 99%, is shifted to the 5 μm limit, which corresponds to a selectivity of the cyclone according to the invention which has not previously been achieved in practice by cyclone separators. The average diameter of the particles, which are separated by 50%, is 1 μm.

In order to improve the cyclone operating variables total separation degree, fraction separation degree and pressure loss according to the invention, a spiral cyclone inlet channel according to the embodiment described is not absolutely necessary, but a tangential or helical inlet channel of the cyclone can also be used.

Further advantages, features and possible uses of the present invention result from the following description of preferred exemplary embodiments in conjunction with the figures. Show it:

1 shows a schematic longitudinal section of a cyclone embodiment with an immersion tube column according to the invention, the gap immersion tube having a screw-shaped entry edge and a diffuser-like gap channel! having, 2 shows a schematic cross section along the section line II-II in FIG. 1,

3 shows a schematic longitudinal section of a cyclone embodiment with an immersion tube column according to the invention, the gap immersion tube being provided with four inlet channels arranged in a helically offset manner, each with a straight entry edge,

4 shows a schematic cross section along the section line II-II in FIG. 3,

5 shows a view of the slotted immersion tube according to the invention with four inlet channels arranged in a helically offset manner with respect to each other, each with a straight entry edge and swirl tube centered around the cyclone axis within the immersion tube column,

6 shows a cross section of the gap dip tube according to the invention according to FIG. 5 along the section line III-III in FIG. 3,

7 shows a schematic view of a gap immersion tube according to the invention with two parallel-walled gap channels arranged symmetrically at the same axial height and axially covered by upper and lower plates.

FIG. 1 shows a schematic view of a gap immersion tube according to the invention with a screw-shaped parallel-wall gap channel which is designed with a screw-shaped inlet edge and a screw-shaped outlet edge as an inlet channel for the swirl tube,

9 shows the two-stage solid-state device according to the invention with a shielding cone which is arranged around the central immersion tube below the cylindrical shielding container.

Fig. 10 is a schematic representation of the flow profiles with axial and tangential velocity v and so, which form in the swirl tube with subcritical and supercritical swirl flow, and 11 shows particle size distributions of the fine material in the clean gas channel of the cyclone separator according to the invention (curve 25) compared to the particle size distribution of the fine material in the clean gas channel of the same cyclone separator without a dip tube column according to the invention (curve 26). 5

A conventional cyclone serves as the basic construction of the cyclone separator according to the invention with two separation spaces and static guiding devices. The four basic components shown in FIGS. 1 and 3, namely the cyclone housing 12a, 12b, the spiral inlet channel 11, the cylindrical

10 scbe dip tube 5 and the solid collecting container 2a are therefore also used as components of the cyclone separator according to the invention. The cyclone housing consists, in a manner known per se, of an upper cylindrical outer jacket 12a and an axially downwardly tapering lower conical outer jacket 12b, although the height of the cylindrical

15 see housing is greater than the height of the conical housing. Both jacket parts 12a and 12b enclose the outer separation chamber 3a. The cylindrical immersion tube 5, which is centered about the cyclone axis 1 and which serves to discharge the dedusted two-phase flow (gas + fine material), projects into the cylindrical outer separation chamber. The tangential or spiral

20-meter inlet channel 11 is intended to supply the accelerated two-phase flow (gas + feed material) entering the cyclone to the outer separation chamber 3a. According to FIG. 3, the lower conical cyclone jacket 12b ends on a cylindrical shielding container 20 with an annular gap-shaped outlet opening 22 for the separated coarse material that is used in the conventional

25 solid collection container 2a is stored below the shielding container 20.

After the cyclone design according to the invention in FIGS. 1 and 3, the conventional immersion tube 5 is first of all replaced by a slit gap immersion

" ₀ robr 6 axially extended, the helical leading edge 9a (Fig. 1) or straight leading edges 9b (Fig. 3) over the suction height h. stretch out. Although suction is known via a slotted gap dip tube (DE-OS 32 23 374), the invention lies in the fact that the gap dip tube 6 is open on its lower end face and a gap channel

“_ 10, which is used as an inlet channel for a dip tube column, whose axis is to be regarded as the center of the vortex core (cyclone eye). The arrangement of the central immersion tube 7 arranged below in the axial extension of the gap immersion tube (6) means that the complete immersion tube 1 pipe column 5, 6, 7 surrounds the entire height of the separating chamber h 'and can therefore additionally be regarded as a stabilizer of the external swirl flow in the separating chamber 3a. The generation of an inner swirl flow and therefore a subsequent separation in the inner separation space 3b of the 5 central immersion tube 7 (FIG. 4) or of the swirl tube 17 (FIG. 3) enable several parallel-walled gap channels 10 (FIG. 3 and 4), a gap channel 10 designed as a curved diffuser (FIG. 2) or a helical parallel-wall gap channel, each parallel-wall channel causing a flow-accelerating effect and being able to produce a supercritical swirl flow. The outer swirl flow runs out on an outer section of the central immersion tube 8 designed as a shielding cone 4, and the inner swirl flow is centered about the swirl tube axis 1. The central immersion tube 7 penetrates the conventional solids collection container 2a and is ^■

15 gas-tightly connected to a second solid collecting container 2b below the first, so that no gas flow is possible between the two containers.

. In the example shown in Figure 2 is cross-section of the cyclone _ inventive separator _n according to Fig -. 1 is below the tangential inlet channel 11 a baffle hen vorgese¬ such in the parallel to the cyclone cover 15 plane 27 that an axially uniform inflow into the gap passage 10 is guaranteed without short-circuit currents. The baffle 27 extends from the center angle ^ = 0 °, which from the transition point in the zy / indri- " _j . scben outer jacket 12 of the cyclone housing tangentially entering outer wall of the inlet channel 11 is determined up to the center angle n = 180 ° as a ring collar around the dip tube 5. From there, the front edge of the guide plate in the direction of rotation of the swirl flow runs approximately tangential to the outer circumference of the ring collar up to the inner wall of the inlet channel 11 of _n its bottom, while the baffle 27 from where the Ringrau cross - section between the immersion tube circumference and. Completely covers outer mat / 12 up to the central angle “= 0 ° and ends there in a radial edge that extends from the circumference of the ring collar to the outer casing 12. The outer mouth of the gap channel lies under the latter section of the guide plate 27. The annular collar formed by the guide plate prevents the particles in a solid flow near the wall (boundary layer flow) on the cyclone cover 13 and along the outer circumferential surface of the dip tube 5 directly into the gap channel be transported. The spiral inlet 11 of the cyclone and the spiral outlet housing 8a required for energy recovery with a central, cone-shaped recess core 8b can be seen from the cross section shown in FIG. 4 of the cyclone separator from FIG. 3, the gap immersion tube 6 being an inlet guide device for the outlet spiral 8 is to be considered. The flow arrows illustrate the flow in the same direction between the cyclone inlet and the cyclone outlet.

5 shows the view of a split immersion tube 6 according to the invention with four inlet channels 10, each offset along a helix, each with a straight, axial leading edge 9b, and the swirl tube 17 centered around the cyclone axis 1 within the immersion tube column 5, 6, 7 . The cutout 15 (see also FIG. 6) in the gap immersion tube 6 are offset from one another by 90 °.

FIG. 6 shows the cross section of the gap immersion tube (6) according to FIG. 5 with the outer and inner contours of the gap channel 10 parallel to one another. The inlet area ^* into the gap channel 10 and its outlet area into the swirl tube 17 are spiral. The inflow into the swirl tube 17 takes place exclusively via the gap channel 10, so that each gap channel is provided with an upper and lower cover plate 19 for the ring cross section between the swirl tube 17 and the gap immersion tube 6.

If the gap immersion tube 6 is provided with two gap channels at the same axial height in accordance with FIG. 7 or with a helically rising entry edge 9a and exit edge 9c according to FIG. 8, the cyclone axis 1 and the swirl tube axis are likewise identical, since one is related to the cyclone axis 1 Symmetrical inflow into the swirl tube 17 takes place, with each execution of the gap immersion tube 6 forming a dead water area 16 as a result of the swirl flow, in which backflows 18 are present.

FIG. 9 illustrates the two-stage solids discharge device according to the invention with a shielding cone 4, which is arranged around the central immersion tube 7 below the cylindrical shielding container 20, which is connected between the lower end of the conical jacket 12b and the first solids collecting container 2a. The shielding cone 4 is facing downwards the base of the central dip tube 7 attached to this and arranged within the primary solids collection container 2a. A cone-shaped deflector screen 21, which widens downward, is arranged after the cylindrical shielding container 20 on the upper wall of the collecting container 4 and prevents re-whirling of already separated solids. The secondary solids collection container 2b is flanged to the central immersion tube 7 below the primary solids collection container 2a in a gas-tight manner.

10 illustrates the different radial flow profiles of the axial component v and the tangential component Vγ of the flow velocity in the swirl tube 17 with subcritical and supercritical 23, 24 swirl flow, the backflow 18 with supercritical swirl flow the transport of the particles concentrated in the dead water area 16 causes in the secondary solid collection container 2b.

FIG. 11 illustrates the improvement in the separation performance achieved on the basis of particle size distributions of the fine material in the clean gas channel of the conventional cyclone 26 without the dip tube column 5, 6, 7 and the cyclone separator 25 according to the invention.

The embodiment of a cyclone separator shown in FIG. 3 according to the invention works with the following two-stage separation process:

The dust-containing gas sucked in by a compressor flows in a manner known per se into the swirl-generating inlet channel 11 of the cyclone and via this into the cylindrical outer separation chamber 3a. The inflowing gas in the sense of the invention through the gap immersion tube 6 evenly over the suction heights h. sucked off.

The flow in the cylindrical separator arm is a vertebral sink. The gas flows on spiral tracks with increasing speed from the outside in. The generated three-dimensional swirl flow enables the tangential speed component to generate the centrifugal acceleration required for separation on the one hand and the axial component of the speed to spiral the solid along the outer cyclone jacket 12 transported into the primary solid collection container 2a, since even fine dust particles do not follow the streamlines of the gas, because they are carried out of the curved path against the cyclone jacket under the action of high centrifugal accelerations. The same secondary currents are observed on the wall of the separator as in a teacup. This secondary flow along the wall of the conical separating space 12b is useful, however, since it also detects the solid carried on the wall and leads down to the solid collecting container 2a. A strand of solid material forms on concave walls

10 because of the disturbed balance of pressure and centrifugal forces.

The tangential and radial component of the vortex sink flow, the respective speed profile of the gap dip tube 6 over the height of the. , - suction gap h. is constant, are sucked in between the outer contour and the inner contour of the gap channel 10, so that the particles in the outer flow field of the cyclone 3a are forced to separate under constant separation conditions. Since the dimensioning of the entry surface of the gap immersion tube 6 takes place in such a way that the swirl sink flow in the outer separation chamber 3a is not disturbed, the immersion prevails all around

20 tube columns 5,6, 7 always on. strong swirl field, which allows high centrifugal forces to act on the particles in the separation chamber.

The from the primary separation chamber 3a suctioned through the gap passage 10 _"c te gas flow is then directed res 17 to the outer surface of the Drallroh¬ in which a second inner swirl field with the fluidized located core forms 16 of the cyclone, whereby the secondary separation effect is initiated. According to FIG. 10, this inner swirl flow has only a two-dimensional flow field, since a radial speed component (sink flow) is no longer present. By means of the swirl flow within the swirl tube 17, the very fine particles still suspended in the gas flow are "caught" in the dead water core 16 and transported with the aid of the downwardly directed axial component 18 into the secondary solids collection container 12. As a result of the central dip tube 7

35 the particles have sufficient axial scope to reach areas in which all flow components have decayed but where there are still strong tangential speed components.

In the swirl tube 17, as in any curved flow, the static pressure drops sharply from the outside to the inside. The lowest pressure of the vortex prevails in the swirl tube axis or cyclone axis 1. As a result, the compressive force that acts on the particles is significantly greater than the centrifugal force, so that strong secondary flows inward to the cyclone axis 1 favor the secondary separation effect. The solid layers initially bound by the swirl tube inner wall are displaced in the direction of the radial pressure drop, while the cleaned flow stream 23 flows along the inner swirl tube walls.

In the case of a strong swirl, which is aimed for by a corresponding dip tube inlet construction according to the invention, the flow concentrates on a narrow outer ring zone in the swirl tube 17. The axial velocity component v and the radius of the dead water core R “become larger, see FIG. 10. The swirl is no longer constant over the radius r, speed peaks 23, 24 form. According to FIG. 10, the axial speed v is constricted in the cyclone axis 1.

At constant flow, according to the laws of hydrodynamic equilibrium, there is a physical dependency between vacuum force, / Axia / Z component v and swirl strength, which is only changed by the critical swirl. By increasing the swirl, there is a minimum of negative pressure and a minimum of kinetic energy. This increase in swirl finally causes the vacuum to increase to such an extent that a backflow 18 of the axial speed within the vortex core 16 occurs. This phenomenon, in which the swirl flow changes without internal axial backflow in the dead water core ^' into a swirl flow with axial backflow 18 along the cyclone axis 1, is used for particle separation within the swirl tube 17. This desired flow change with maximum backflow is achieved with a high swirl and causes the removal of the particles located in the dead water area 16, which are held captive in the dead water area 16 due to the radial pressure drop. The different behavior of the currents with, weak and strong swirl along the cyclone axis 1, in particular within the gap immersion tube 6, can be attributed to the different pressure changes which an internal backflow 18 from the gap immersion tube in the case of currents with a strong swirl 6 in the downstream central immersion tube 7 or in the secondary solids collection container 2b. A gap immersion tube $, which causes this phenomenon of backflow, is fundamentally suitable for exploiting the secondary separation effect for dust separation from a flowing fluid.

While the primary separation process in the outer separation chamber 3a, in analogy to the conventional cyclone, relies on the effect of centrifugal forces on particles, in order to implement the secondary separation process within the swirl tube, the phenomenon of the flow changeover must be used for the particle separation from a flowing fluid. In this way, a two-stage separation of particles suspended in two-phase flows is achieved in a single apparatus.

The kinetic energy of the swirl flow is recovered by an outlet f spiral 8a arranged above the cyclone cover 13 and dimensioned in a known manner, with recesses, so that both the axial component and the tangential component of the inner swirl flow are decelerated in such a way that The cyclone entry speed and the cyclone exit speed assume the same values with the same pipe cross sections of the raw gas and clean gas channels.

The effectiveness of the two-stage deposition process described could be confirmed by extensive experiments on a cyclone test facility under practical conditions. The reduction of the coarse-grained mass fraction of the fine material in the clean gas channel by installing the immersion tube column according to the invention around the cyclone axis in comparison to a conventional cyclone construction without additional guiding and separating device is shown in FIG. 11 on the basis of comparative particle size analyzes of the fine material, the feed being Quartz flour with an average particle size diameter of 6 μm was used, l / or everything can be determined that not only the overall degree of separation increases or the Solids concentration in the clean gas channel decreases, but also the fractional separation efficiency is decisively improved, since the smallest 90% separated particle size of 15 μm shifts far into the finer particle size range of 2 μm.

By using the invention, the field of application of cyclone separators is significantly expanded. In particular, the cyclone according to the invention could be used as a future application example for the dedusting from the pressure-operated fluidized bed combustion in a combined gas / steam turbine plant. The gas turbine blades are subject to both erosive and corrosive wear, with the erosion force having a strong effect from a particle diameter of __ 10 μm. In addition, the air / flue gas-side pressure loss of the combined process influences the process efficiency to a considerable extent.

Claims

PA TEN TA NSPRÜCHE

1. Cyclone separator with two separator spaces (3a, 3b) and static guide devices for improving the separating capacity with regard to finely dispersed particles from flowing gases and reducing the pressure loss or for influencing the flow field of a centrifugal separator with tangential (11), spiral or screw-shaped inlet channel (11), with an upper cylindrical (12a) and lower conical (12b) cyclone housing, as well as a solids collection container (2a) arranged underneath, a cylindrical immersion tube centered into the cyclone housing from above into the cylindrical separating chamber 5 protrudes to discharge the clean gas stream, characterized gekenn¬ characterized in that a dip tube column, consisting of the series connection of the dip tube (5), a slotted gap dip tube (6) with a helical or straight gap channel (10), and a central dip tube (7), of which the cyclone axis (1) over the entire separating area m height (h) is surrounded, in the cylindrical separating surface of the cyclone separator, penetrates the solids collection container (2a) and is connected gas-tight to a second solids collection container (2b) below the first one, the three submerged tubes (5,6, 7) in mutual open connection and the gap immersion tube (6) is the only suction partial immersion tube.

2. Cyclone separator according to claim 1, characterized in that between the inlet channel (11) and the gap immersion tube (6) this is provided against short-circuit currents baffle (27) is provided.

3. Cyclone separator according to claim 2, characterized in that the guide plate (27) on the dip tube (5) below the cyclone inlet channel (11) in the horizontal plane parallel to the cyclone cover (13) is installed in such a way in the outer separating space (3a) that short-circuit flows of the swirl flow are prevented directly into the suction channel (10) of the slit-immersion tube (6) and the axial velocity component of the swirl flow in the outer separation chamber (3a) is positively influenced with regard to the solids discharge behavior.

4. Cyclone separator according to one of claims 1 to 3, characterized gekenn¬ characterized in that the sole suction gap-dip tube (6) as a flow-favorable inlet guide device for an above the cyclone cover (13) arranged outlet spiral housing (8a) with recess core (8b) is trained.

5. Cyclone separator according to one of claims 1 to 4, characterized gekenn¬ characterized in that the entry surface of the parallel-walled gap channel (10) of the spa-dip tube (6) is designed as a slotted opening within the gap - dip tube shell such that in the inlet area of the

Gap channel sets the required flow velocity at the separating surface according to the existing rotary sink flow, which in turn is tapped at the separating surface as a logarithmic spiral (15) due to the course of the gap immersion tube, so that the curved streamlines through the gap channel (10) in the

Swirl tube (17) entering gas flow along the outer and inner gap channel contour and in the same direction with the cyclone inlet flow

6. Cyclone separator according to claim 1, characterized in that the gap immersion tube (6) is provided with four parallel-walled inlet channels (10) evenly distributed on the circumference of the immersion tube, each with a straight entry edge (9), so that the common diagonal (14) of the four A 90 ° offset recess area (15) provides a single screw line around the gap immersion tube (6) as an inlet channel with accelerating flow for a swirl tube (17) symmetrical to the cyclone axis (1), resulting in dead water within the swirl tube (17) ¬ water area (16) with axial backflows (18) in the central immersion tube (7) forms with a correspondingly high swirl strength, which is determined by the geometrical design of the gap channel (10) and the gap immersion tube (6), and wherein high negative pressure values on the cyclone axis (1) and strong pressure changes in the axis direction the intensive backflow (18) into the central immersion tube (7) and then in the secondary ren solid collecting tank (2b) induce.

7. Cyclone separator according to claim 1 and 6, characterized in that to increase the rotational symmetry and the swirl strength, the gap immersion tube (6) with four helically distributed on the circumference of the immersion tube inlet channels (10) is replaced by a gap immersion tube, either with several on Immersion tube circumference evenly distributed in the same axial height gap channels (10) each with a straight entry edge (9b) or with a parallel-walled screw-shaped gap channel (10), which has a screw-shaped entry edge (9a) and a screw-shaped exit edge (9c), whereby a Supercritical swirl strength with backflows (18) into the central immersion tube (7) is produced if the respective gap channel (10) is designed as a curved deflecting channel with an accelerating effect and the respective gap channel (10) with an upper and lower cover plate (19) is provided, whereby the suction from the outer separation chamber (3a) out finally takes place via a screw-shaped gap channel or via several edged gap channels evenly distributed around the circumference of the immersion tube.

8. Cyclone separator according to one of claims 1 to 7, characterized in that a cylindrical shielding container (20) is interposed between the ko¬ African part (12b) of the outer separation chamber (3a) and the first solids collecting container (2a) in such a way that the outer swirl flow on an outer section of the central immersion tube (7) designed as a shielding cone (4) runs out within the first solid collecting container (2a), so that the separated solid undisturbed without entraining effects in the annular gap (22) between the cylindrical shielding container (20) and the central immersion tube (7) can penetrate into the first solids collecting container (2a) and the solids do not come back through the arrangement of a conical deflector screen (21) below the cylindrical shielding container (20) and around the shielding cone (4) can be whirled into the outer separation chamber (3a).