DE1274560B - Device for dedusting industrial gases - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

BOId

German class: 12 e- 2/01

Number: 1 274 560

File number: P 12 74 560.7-45 (G 30558)

Filing date: September 23, 1960

Opening day: August 8, 1968

The invention is in the field of devices for dedusting industrial gas. Such Device consists of a cross-sectional constriction formed by a confuser and a diffuser, and it works by fogging a film evenly distributed over converging surfaces Liquid in a dusty gas stream in the diffuser part with subsequent separation of Liquid and gas. The invention solves the problem of adapting devices of this type to differently occurring Adjust gas quantities in that the gas throughput corresponds to the amount of gas produced is increased or decreased without sacrificing an optimal efficiency of the system must become.

It is known to use Venturi tubes to remove dust from gases and to use the liquid lengthways to accelerate the preferably conical wall of the confuser so that in the downstream Diffuser as complete as possible atomization of the liquid to bind the dust particles entry. In these known arrangements, the width of the cross-sectional constriction is constant, and therefore the flow velocity of the gas changes with different gas throughputs, which affects the generation of the turbulent zone in the diffuser part. Will have a certain minimum value If the gas flow rate falls below this, the turbulence and thus the efficiency of the system decrease. The gas throughput can of course be increased by a corresponding supply of fresh air to the dusty gas are kept constant, but this means an unnecessary increase in throughput or the Conveying capacity in addition to the difficulties caused by adjusting the volume, the temperature etc. of the fresh air.

It has also already been proposed to use the narrowest cross-section between the confusor in Venturi dust collectors and to make the diffuser changeable by pivoting guide surfaces in order to adapt it to achieve different amounts of gas to be enforced. By the angle that is between the stationary, conically extending confuser surface and the pivotable guide surfaces results, a zone of undesirable turbulence is created in the confuser. Further sit down during operation in the dead space behind the swiveling guide surfaces dust deposits are fixed, which in the long run block the pivoting of the guide surfaces to change the cross-section.

It has been found that an adaptation of a Venturi deduster to different occurring Device for dedusting industrial gases

Applicant:

Society of

Ludw. von Roll'schen Eisenwerke A. G.,

Gerlafingen (Switzerland)

Representative:

Dr.-Ing. R. Meldau

and Dipl.-Ing. G. Meldau, patent attorneys,

4830 Gütersloh, Carl-Bertelsmann-Str. 4th

Claimed priority:

Switzerland of September 29, 1959 (78 815),
dated November 13, 1959 (80 581),
dated May 18, 1960 (5695)

Gas quantities with constant optimal efficiency and at the same time avoiding harmful Can reach dust deposits when the converging the confusor and diffuser part delimiting and diverging surfaces are mutually displaceable and so the narrowest cross-section is adjustable so that regardless of the amount of gas to be enforced at this point a constant flow rate of the gas is achieved. This makes it possible to continuously run Maintain converging and diverging surfaces, eliminating any undesirable effects in the confuser Turbulence occurs because it just depends on an even action of the flowing gas on the liquid film to ensure a spontaneous nebulization of the liquid to reach the highest speed at the point. ,

Furthermore, the cross-sectional constriction can always be advantageously adjusted so that only a part of the Liquid is nebulized. The non-atomized portion of the liquid coats the diverging ones Surfaces of the diffuser and underflows deposited dust particles, which are transported away in this way will. Thus, the liquid becomes at the same time

809 589/408

Cleaning the diffuser zone from unwanted dust deposits.

The advantageous embodiment of a device according to the invention is characterized in that the converging and diverging pairs of surfaces forming the cross-sectional constriction are known per se Way are mutually displaceable.

An improvement of the invention is achieved when the converging and diverging

The liquid film flowing downward on the surface 1 is caused by the gas in the zone of the cross-sectional constriction 4 under the action of the prevailing there turbulent gas flow nebulized. The degree of fogging, i.e. H. Size and size distribution of the atomized liquid droplets is determined by the extent and turbulence of the zone around and after the cross-sectional constriction 4 is determined. In space 9 is the gas or gas mixture with the

Pairs of surfaces designed as parts of nozzle bodies are mixed with atomized liquid. It should be emphasized det are that have a prismatic shape with triangular that the arrangement of free-standing surfaces because of have gem cross-section and in a flow of the formation of vortex zones below the channel are arranged with a rectangular cross-section. Area is practically not cheap and that the A particularly advantageous embodiment has surfaces always parts of flow-profiled is given by the converging and diverging bodies.

Yawing pairs of surfaces that follow in a flow Depending on the intended use of the device

Channel with a circular cross-section, rotationally symmetrical, now in the direction of the outflowing gas are formed and an annular consumer for the air-gas mixture or a separating nozzle gap release, the corresponding zone in which the liquid, for example, under corresponding pairs of surfaces on the one hand by the shell effect of a gravitational field (calming chamber) area of one in the flow channel along which a cyclone or cyclone is separated from the gas. Longitudinal axis displaceable body and on the other hand F i g. 2 shows the two converging surfaces

formed by the wall of the flow channel 11 and 12 as parts of the nozzle body 13 and 14. The are. Nozzle body 14 is in the direction of the double arrow

Another improvement of the invention is 25 movable, with between the nozzle body and but achieved by the fact that the wall 17 of the flow channel seals 15, distributed liquid the fixed and displaceable 16 are provided.

Coated surfaces of the confuser. The nozzle bodies 13,14 together form the

The invention is carried out in some embodiments by moving the nozzle body 14 in the direction with reference to the drawings, the variable cross-section is explained in more detail below with the double arrow. It shows constriction 18, which is also referred to as the nozzle gap.

F i g. 1 shows the perspective view of the converging surfaces 11, 12 are shown by mas a device according to the invention in the channel-like inlet chambers 19, 20 Section, loaded with a film of liquid. The shielding

F i g. 2 the schematic representation of a front surface 21, 22 shield the gap-like exit ducts Embodiment of the openings 23,24 according to the invention against the flowing gas. the Mixing device with two nozzle bodies and two feed lines, which the chambers 19 and 20 with Inlet chambers for the liquid, supply liquid, are clarity

F i g. 3 a schematic representation of a rota not shown. Of course she must The symmetrical design of the feed line according to the invention for supplying the movable moderate mixing device with a fixed inlet nozzle body located chamber accordingly

be flexible or adaptable.

The gas flowing through the device at a correspondingly high speed nebulises the Liquid flowing over the edge 25 of the nozzle body 13 at least in part. The one over the edge 26 of the nozzle body 14 flowing liquid film is also at least partially atomized. the Turbulence zone begins approximately at edge 25 and

The symmetrical embodiment of the invention 50 extends down into the space 27 below Moderate device with two fixed inlet chambers of the nozzle body 13,14. By regulating the flow for the liquid. sigkeitszufuhr it is possible to the walls 28,29 des

In detail, FIG. 1 the two surfaces of 1 flow channel with downward flowing liquid and 2, which are to be covered against each other in a flow channel 3, since the energy of the gas is only one converge on another. In the flow channel 3, the gas 55 is able to atomize a certain amount of liquid, or gas mixture from top to bottom in the direction Especially for the use of the device, both

chamber for the liquid,

F i g. 4 shows the schematic representation of a device according to the invention in a cleaning system for industrial gases,

F i g. 5 shows a dedusting system in section using a rotationally symmetrical embodiment of the device according to the invention, FIG. 6 a schematic representation of a rotary

of the arrow. The surface 2 is in the direction of the The double arrow can be displaced in parallel and thereby forms a variable cross-sectional constriction with the surface 1 4 in the flow channel 3, the front wall of which has been broken away for the sake of clarity. The feed chamber 5 is through the feed line 6 with a liquid, e.g. B. water, supplied. The liquid flows through the gap 7 onto the surface 1

for example, for dust removal, this controllability is possible because of the possibility of possibly occurring Preventing solid deposits is important. It should be emphasized that the device according to the invention is not limited to flow channels with a square or right-angled cross-section. Man can, for example, form the nozzle body in a ring shape and arrange it coaxially, so that a ring

and forms a liquid film on it. The impression 65 shaped nozzle gap results. This construction screen surface 8 shields the inlet chamber 5 against moderate influences and particularly favorable effects in terms of their mode of operation of the gas flow and thereby ensures the current embodiment of the pre-uniformity according to the invention of the film at the exit point. The direction is shown in FIG. 3 shown. Furthermore, at

of the device according to the invention, one or both nozzle bodies can be designed to be movable in all embodiments; in particular in the rotationally symmetrical design, the inner or outer or both nozzle bodies can be moved to change the nozzle gap. In Fig. 3, the one nozzle body 30 is firmly connected in a flow channel 32 with a circular or ring-shaped cross section to the outer wall of the flow channel 32 or forms part of this wall. The other nozzle body 31 can then be rotationally symmetrical, for example in the form of a double cone movable in the directions of the double arrow, and lie coaxially with the outer nozzle body 30 in the flow channel. From the inlet chamber 33 designed in the form of an annular channel, the liquid passes through the gap 34 into the flow channel, flows downwards on the surface 35 and is in the zone of the cross-sectional constriction 36 with the gas flowing downwards from the top with at least partial atomization of the Liquid mixed. When using the device for cleaning gases, the gas flow is preferably directed downwardly flowing in a spiral around the axis AA , the space 37 merging into a cyclone. In the cyclone the rotating gas separates from the liquid and is discharged through the pipe 38 in the direction of the arrows upwards. The liquid atomized in the dusty gas stream binds a large part of the solid particles contained in the gas as dust in the turbulent mixing zone generated by the cross-sectional constriction 36, which solid particles can then be separated from the gas together with the liquid in space 37.

The liquid to be atomized can be introduced into the annular inlet chamber 33 in such a way that it rotates about the axis AA. This is due to the concave surface of the liquid in FIG. 3 indicated. The advantage of this operating mode is that water containing solids can also be used when cleaning gases. The settling of solid parts in the feed chamber 33 is prevented particularly reliably by this rotation. The speed of rotation in the feed chamber 33 must be higher than the dragging speed for the solids contained in the liquid.

F i g. 4 shows the arrangement of a device according to the invention in a cleaning system for Industrial gases. The gas to be dedusted is introduced into space 39 and flows through downwards the cross-sectional constriction 42 delimited by the two nozzle bodies 40, 41. The nozzle body 40 is movable in the direction of the double arrow and enables the cross-sectional constriction 42 to be changed. The two converging surfaces 43, 44 are supplied with water through the inlet chambers 45, 46, which flows downward in a film-like manner on these surfaces and at least partially through the gas flow is fogged. In space 47 there is an intensive mixing of the gas to be cleaned with the sprayed water instead, whereby the water binds the majority of the solid particles. In the calming and separation chamber 48, the water with the bound solid particles settles and becomes Discharged through the dirty water drain 49. The cleaned gas flows through the clean gas outlet 50 away. In order to ensure complete detection of the gas to be cleaned, the movable The nozzle body 40 is provided with the seals 51.

F i g. 5 finally shows a dedusting system for industrial exhaust gases in section using the preferred, rotationally symmetrical embodiment of the device according to the invention. For example, water is used as the liquid.

The gas to be dedusted, for example an iron oxide-containing exhaust gas from a metallurgical Operation, flows out of the space 60 in the direction of the two arrows downwards against the nozzle gap 65. The annular and converging surfaces 61 and 62 are covered with a film of water, the is created by the inflow of water from the inlet chambers 66 and 67. Both the inner feed chamber 67 as well as the outer inlet chamber 66 are on their upper side with the shielding surfaces 68 and 69 respectively. The supply organs for the feed water to the inlet chambers 66 and 67 are not shown. Of course, the supply line to the inlet chamber 67 must have a flexible part, since the inner inlet chamber 67 can be displaced with the part 64 in the direction of the double arrow.

By moving the part 64 in the direction of the double arrow, the nozzle gap 65 is due to the Shifting of the gap edges 72,73 against each other changed. This allows the dust collector be adapted to the operating condition of the gas generator, with seals 79 between the fixed and the moving part as well as the control linkage 78 gas loss or false air entry into the system impede. If the gas supply changes, an automatic control (e.g. electrical, pneumatic, hydraulic) this adjustment of the nozzle gap, d. H. the displacement of part 64 take over. The dusty gas is in the zone of the nozzle gap and in the space below the Nozzle gap (diffuser), depending on the flow velocity, pronounced turbulence phenomena and at least partially atomize the water. It is beneficial if this is for dust removal The water used contains solids, since liquids generally contain solids from the gas entrained solids, e.g. B. dust, bind better than pure liquids. The rotationally symmetrical Construction of the inlet chambers can create a rotating flow of water in the annular Chambers are generated, which prevents the settling of the solid. The rotation itself can by suitable means, such as guiding the water flow entering the chambers, pumps and others Funding facilities, generated or regulated.

The settling of the solid matter from the dusty gas on the walls of the dust collector can be effectively avoided by feeding more water into the system, than the gas can nebulize. The excess of water washes the walls of the nozzle bodies 63 and 64 especially in the areas where dust can get on the walls. This is particular for the outer wall 63 of importance when the dusty gas spirals around the The longitudinal axis of the dust extractor is guided in a rotating manner, because in this case it is heavy due to the centrifugal force Parts of this outer wall 63 are knocked down.

After an intensive mixing of the dusty in the turbulent mixing zone 74 (diffuser) Gas is achieved with the atomized water, the solid and water particles beat each other depending on the flow conditions under the effect of centrifugal force or gravity. In the The calming or separation zone 75 is useful for separating gas and liquid or solid completely, and the dedusted gas flows in the direction of the curved arrows through the funnel-shaped Discharge nozzle upwards into the clean gas pipe 76. The water containing solids, on the other hand, flows through the dirty water drain 77 downwards. With the proposed recirculation of the solids-laden Water, the water portion leaving by evaporation with the gas must be replaced. By adding fresh water and / or settling part of the solids the solids content in the water is expediently set to a certain value. Through this the construction of expensive settling systems for a complete treatment of the wastewater can be achieved avoided and fresh water consumption reduced. A suitable arrangement for the Recirculation of the waste water consists in a mixing vessel with supply lines for the waste water and the fresh water. It should be emphasized that in this way it is possible to reduce the water consumption of the system to the water removed from the system by evaporation. To execute the Dedusting system is also to be noted that it has a, compared to the known Dust collectors have a similar effect and simple structure.

The conditions of a dedusting system according to FIG. 5 are explained using the following numbers.

The entire system according to FIG. 5 has an overall diameter D ₄ of 1750 mm; the diameter of the annular gap D _R is 1450 mm, the height of the system 3100 mm; the gas throughput Q _{a of} this system is designed for 3600 Nm ³ / h at a gas inlet temperature t _E between 600 and 1000 ⁰ C; the gas outlet temperature t _A is approximately 50 ° C. With a solids content of an industrial waste ^{gas containing iron oxide of 20 to 50 g / Nm 3} , an average degree of precipitation of 94% results. The water circulation rate Q is 120m ³ / h, the effective water consumption with recirculation of the dirty water is limited to the replacement of the evaporated water portion and in this example is about 5 m ³ / h. The speed of the gas flow in the narrowest cross-section, which should not be exceeded, will be 80 m / s for optimal nebulization with the media used (industrial exhaust gas and water). The mean dust concentration of the pulp during recirculation was 8 g / l in this operating example.

A possible rotationally symmetrical embodiment of the device according to the invention with two solid, concentric inlet chambers for the liquid are shown in FIG. 6, which for example also can be operated as a dedusting system with industrial waste gas and water.

From the spiral-shaped, water-cooled inlet housing 80, the gas flows through one to the adjustable nozzle gap 81 towards converging channel. The fixed nozzle body 82 is in the out Fig. 3 known shape formed by the outer wall of the system and also has the there schematically indicated inlet chamber 83 for the liquid. The other embodiment consists in essentially in the fact that the inner, movable nozzle body 84 consists of a simple conical tube consists, which below the nozzle gap has a smaller opening angle than the fixed nozzle body 82 and can be raised and lowered for regulating purposes. The system also has a second, arranged above the inlet housing 80, fixed inlet chamber 85 for the liquid. These Upper inlet chamber 85 has a conical guide tube below the inner overflow edge 86 with the same opening angle as the movable nozzle body 84. Because the liquid in the feed chamber 85 rotates, the liquid film remains on the inside of the guide tube due to centrifugal force 86 adhere, which also shields this film against the effects of the gas flow. At the At the lower edge of the guide tube 86, the liquid enters the channel of the gas flow and is removed from it in the manner already described together with the liquid from the inlet chamber 83 at least partly fogged. In the calming and separating chamber 87, the now loaded with solids Liquid and gas are separated, the gas leaves through the central funnel, which is at the same time the movable nozzle body 84 forms, the system upwards, while the pulp is diverted downwards will. This embodiment is also particularly suitable for the recirculation of the sludge running off. The adjustability of the nozzle gap and the adjustment of the same to the gas throughput have to The result is that the mixing effect is kept uniform even when the gas throughput changes can be. It is of course irrelevant whether this change in the cross-sectional constriction caused by the movement of one or both nozzle bodies and whether the nozzle body be moved parallel or transversely to the direction of flow. Also the shape of the nozzle body can be designed in different ways, and in addition to those shown in FIGS. 2 to 6 are also shown cross-sections other polygonal or continuously curved designs are possible.

Claims (3)

Patent claims: 1. Device consisting of one formed by a confuser and a diffuser Cross-sectional constriction for dedusting industrial gas by nebulizing an over converging Surfaces as a film evenly distributed liquid in a dusty gas stream in the diffuser part and subsequent separation of liquid and gas, thereby characterized in that the converging and diverging which form the cross-sectional constriction Pairs of surfaces are mutually displaceable in a manner known per se. 2. Apparatus according to claim 1, characterized in that the converging and diverging surface pairs parts of nozzle bodies (13,14) which have a prismatic shape have a triangular cross-section, and in a flow channel with a rectangular cross-section are arranged. 3. Apparatus according to claim 1, characterized in that the converging and diverging pairs of surfaces in a flow channel (32) with a circular cross-section rotationally symmetrical are formed and release an annular nozzle gap (36), with training the corresponding pairs of surfaces on the one hand by the lateral surface of an im 10 Flow channel along its longitudinal axis displaceable body (31) and on the other hand through the wall of the flow channel (32). References considered: British Patent Nos. 773,323, 764,429; U.S. Patent Nos. 2,684,836, 1,960,260. For this purpose 2 sheets of drawings