DE6934102U - DEVICE FOR SEPARATING AND / OR RECOVERING FINE MIST AND DUST PARTICLES FROM GAS TROEMS - Google Patents

Description

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PATENT ADVOCATE

DR. E. WIEGAND DIPL-ING. W. NIEMANN, DR. M. KÖHLER DIPL-ING. C. GERNHARDT

MÖNCHEN HAMBURG

TELEPHONE 55547 «8000 MDNCHEN 15,

TELEGRAMS. KARPATENT NUSSBAUMSTRASSE 10

January 12, 1970

¥ ■ 14470/69 15 / Sch G 69 34 I02.2

Ovitron Corporation Newburgh, New York, V.St.A.

Device for separating and / or extracting fine mist and dust particles from gas streams

The invention relates to a device for separating and / or extracting very fine mist and dust particles Gas flows.

There have already been numerous devices for Abtren-ημ ^ and / or recovery of particles or mists suspended in air or other gases. Under the The term "particles" means finely divided pesticides and the term "mist" means finely divided liquids. Because the particles occur in a practically unlimited variety of physical forms and one is the same Having variety of physical and chemical properties, the previous devices were common directed at the removal of particles that fall into relatively broad definable categories.

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For the separation of mist or the finest dust there is one Number of procedures known. Electrostatic precipitators are used that have average operating costs require very high initial investment costs. With 'corrosive gases there are very often insurmountable Problems for the electrostat.

I ¹ Some working methods are known for mechanical separation. Cyclones can only be used successfully for particle sizes down to about 10 microns. Clogging filters are known for larger particle sizes and are limited to absolutely dry, non-baking dusty materials.

For wet washing of the finest dust materials is the Venturi device is known to be effective. The successful operation of a venturi scrubber is based on the acceleration and subsequent deceleration of the dust-laden one Gas including the scrubbing liquid. The acceleration and subsequent deceleration lead to agglomeration the fine particles, which are then separated together with the washing liquid.

In accordance with the invention there is provided a multiple venturi scrubber in which an essential Separation efficiency is achieved with relatively low energy.

Like from Pig. 1, the gas is intensively mixed with the scrubbing liquid and then distributed over a number of slot-like Venturi nozzles. In the nozzles, the contaminated gas is accelerated over a distance A from a speed V ₁ to the speed V ₂ (FIG. 2). The acceleration is calculated as follows:

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The problem of finding a separator that will remove particles of a wide range of sizes, is related to the problems of the capacity for the distance. and the degree of the separation efficiency or performance that must be achieved.

The device according to the invention aims to solve these problems in that it provides a greater total capacity can deliver and separates more particles per volume than most of the previous separation devices or combinations of separators of comparable size.

Another problem with current devices is that when separating smaller Particulate clogging often occurs and such devices are generally not easy to clean can.

In accordance with the invention, these problems are overcome by the provision of a separating device in which the problem of clogging is considerably reduced when operating according to the regulations. Furthermore, the device according to the invention can be made of corrosion-resistant materials, for example plastics, without its effectiveness being impaired.

Below it is shown that the significant acceleration conference either through a large Gesehwindigkeitsdif = or obtained by a short acceleration distance

can be. The magnitude of the acceleration is the determining factor for the separation efficiency. Because according to the invention If the gas is distributed through a large number of slot-like Venturi nozzles, it is possible to use the acceleration section To keep A very low, so that with a small difference in speed, very large acceleration forces can be obtained. Since now the speed difference for the pressure loss (the required energy) is responsible, less energy is used for the same acceleration than with the currently known forms of training required by venturi scrubbers.

It has been found that the extent and the speed of the acceleration of the Gasspcuhgemiscb.es, the gases, Contains impurities and washing liquid, through the slot a great influence on the extent of the achieved Have separation.

The speed of acceleration is determined by the converging part of the slot, and it was found that the separation is most effective when the converging portion of the slot extends for a distance from about 1 to 10 mm, preferably 2 to 4 mm. A a suitable slot has an angle of convergence in the range of 10 to 12o ° or advantageously between 8o and 100 °. The purpose is to effectively achieve maximum acceleration of the gas and entrained material with minimal energy loss due to turbulence, friction and similar pulling or reducing forces.

The amount of acceleration is determined by the size of the slot and the length of the converging section in the area of the greatest constriction, i.e. the throttle.

The width of the slot, which proves to be particularly advantageous proved, is between about o, o2 and 3 well, preferred o, 1 to 3 mm. It was found that the cross-sectional width of the slot at the throttle was still favorable for the separation results when it has a large multiple of the size of the particles to be separated.

Obviously, it is difficult to find the optimal dimensions for a slot to predict. Often the size of the particles is not exactly known due to their transition state. Furthermore, the particles to be separated, mist and gases, must have other physical properties affect their tendency to agglomerate or to mix with the washing liquid, also taken into account e.g. the physical shape of the particles, the surface tension of the mist droplets and the absorption properties of the liquid detergent.

Experience has shown that optimum separation is achieved when the maximum gas velocity through the Schiit "in the range between 30 and 200 m per lake lies. Higher speeds are required if the particles show a lower tendency to agglomerate, and slower speeds are sufficient if the particles are easily agglomerated.

Because of the large number of variables involved in setting up a particular separator, the Appropriate combination of slot dimensions, fluid delivery and acceleration can be varied to be the most effective Combination to result. However, in accordance with the invention, the favorable dimensions generally fall within those above listed limits, so that according to the teachings of the invention one obtains a separator that is extremely is effective and less costly to build and use

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is entertained, ala most of the hitherto "known institutions, capable of achieving the same result are.

When carrying out the separation process, the gases are, if necessary, below the boiling point of the Wash liquid cooled before entering the separating device in order to evaporate the wash liquid during to prevent the separation process. If necessary, can the gases are cooled in a separate cooling system before entering the separation device.

Any washing liquids that keep the slots clean can be used and can accordingly can be chosen to combine with the impurities to form a useful by-product.

The dimensions of the slot, the type and amount of medium used and the acceleration due to the linear Throttling the slots depend on the physical properties of the particles to be separated and their inclination dependent on agglomeration with the washing liquid.

The more resistant the dust materials and mist to agglomeration or association with the The washing liquid, the narrower the slot opening and the greater the acceleration of the mixture be through the slot.

One of the main advantages of complying with the regulations According to the invention constructed separation devices is that the separation of particles one Size below a micron are suitable and yet not subject to clogging, as is the case with the

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Time known mechanical devices for such term small particles can occur. Loss of effectiveness due to constipation was a major problem with the previous devices, so that the absence of a risk of clogging is a significant improvement over represents the separation devices of the previous technology.

Another advantage of the invention is that the contaminated gases and those formed during their purification Agglomerates do not touch moving parts during the separation treatment.

Another advantage of the invention is that the devices can be easily constructed from materials that are resistant to chemically aggressive dust materials, mists or gases or their liquid solutions are.

The invention is explained in more detail below with reference to the drawing.

Pig. Fig. 1 shows a sectional view of an embodiment of a device according to the invention, comprising a number of adjacently arranged slots.

Pig. Figure 2 shows a cross-sectional view of an embodiment of a mouthpiece slot according to the invention.

With reference to the drawing ^, V is ₁ . . the velocity of the mixture of gas and liquid before entering the converging section or part 13 of the slot and is generally very small compared to V ₂ »V ₂ represents the maximum velocity reached by the gas when it passed through the restricted Area 16 of the throttle "C" of the slot flows. During operation, the speed

934102

speed Vp advantageously above 30 m / sec and still
advantageously held between about 50 and 200 m / sec in order to achieve the desired acceleration from V. to Vp within the distance A, so that the desired effect
results.

The rod-like or bow-like components that form the venturi openings are according to Pig. 1 put together to form walls and form a cavity into which the gas enters. These walls can also be designed in a curved manner. The addition of liquid by means of spray nozzles takes place in the chamber 3o before the gas enters through the
Components formed hollow column 11 enters.

example

The residual gas cleaning of a coal-heated power generation station was carried out with a test device with the following effectiveness dimensions:

Width of the slot at the entrance

Slit width at the narrowest point

Acceleration distance speed speed

D = 4.9 mm

B = 0.5 mm A = 3 mm V- = 5.1 m / sec V ₂ s 50 m / sec

The acceleration b was thus 413,000 m / sec.
The pressure drop was 19o mm water column.

The dust load in front of the separating device was 5.66 g / m ⁵ . The dust content after the separator was 0.045 g / m ⁵ . The separation efficiency was $ 99.2.
Water was used as the washing liquid.

69343

Fig. 1 explains an embodiment of the invention, employing a series of annular or circumferential slots meeting the above criteria. As can be seen, the slots are elongated, in this case in the circumferential direction, and are far longer than the width B the slot opening. An inlet conduit 1o is connected to the open bottom 21 of the inner chamber 11, whereby the exhaust gas is introduced into the separator. The walls of the inner chamber 11 consist of a series of congruent annular elements coaxially aligned one above the other and a cylindrical chamber limit.

The inner peripheral edges 12 of each element are beveled and result in the formation of the converging portion 13 of the slot between adjacent components. The upper and lower surfaces of each component have parts 3 and 4 which form a constriction or throttle.

The annular members can be spaced from one another in their coaxial position by any conventional means Construction, for example, a series of spacers that are placed between the components, are held to the appropriate Distance to give the desired arrangement and mounting.

An upper part 19 closes the inner chamber so that the only exit for those introduced in it by line 1 ο Gases takes place through the annular slots 2o between adjacent components.

A spray nozzle 28 attached in front of the inner chamber 11 provides the device for introducing the washing liquid into the inner chamber in a form that mixes with the exhaust gases, even before the gas enters the inner chamber 11

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An annular outer chamber 22 surrounds the inner chamber. A drain 25 is attached to the bottom of the outer chamber to allow the accumulated liquid and solid material coming out of the slots to be withdrawn and settles on the floor of the outer chamber »

The outer chamber has a gas outlet 26 through which the cleaned exhaust gases are removed.

The gas flow between the inner chamber and the outer chamber can be controlled by fans or blowers, which are relatively for withdrawal from the outer chamber are supported.

As can be seen from the drawing, the gas flow and liquid enter the chamber in a substantially more perpendicular manner Upward direction on assuming that the device is placed on a horizontal platform is. In other words, the gas flow and scrubbing liquid occur in one substantially to the axis of the device parallel direction. The center lines of the slot-like Venturi nozzles are in the preferred embodiment at right angles to the axis of the device. Gas flow and washing liquid enter the nozzles in one direction different from the axis of the device and therefore substantially at right angles to the axis of the Device in the preferred embodiment.

The number employed in a specific facility Components are determined by the volume flow of gases through the unit, the density of these gases and the dimensions of the slots determined. Using these parameters, the required slot footprint can be calculated

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for the gases according to "known formulas for a volumetric Determine the liquid flow and the required number of slots can be determined by making the appropriate ones Build up number of elements.

During operation, the exhaust gases to be cleaned are released into the Inner chamber 11 is introduced through the gas inlet line .1 o, a washing liquid, for example water, is passed through introduced a spray nozzle. The mixture of gas and liquid or gas and spray liquid is then passed through the I accelerated linear throttling of the slots.

The impurities with lower mass than the Sprühflüssigkeitsteilchen be accelerated by the opposite to the liquid inlet I ^s Prühung rapid gas flow.

I This condition causes multiple collisions of the

I Impurities and the droplets of washing liquid cause

I gently, whereby the agglomerates are obtained.

! The agglomerate resulting from this process

I is relatively difficult at the time when

] it leaves the slots in the inner chamber and collapses

ι men with the liquid injection to the ^ oden the external

I chamber. Here the agglomerates are

T merate recorded and continuous. Through the sequence 25

I deducted.

Claims (9)

I I t I 11 11 * 1 I I I I I> ι ι ι at Ii ι III 11. ' »- 12 - Claims for protection 1. Device for separating entrained dust particles and mist from gas streams consisting of a chamber (11) for receiving a washing liquid with the gas flow, devices (1o, 28) for introducing the gas flow and the washing liquid into the chamber in a predetermined direction, a plurality of adjacent, spaced-apart slot-like Venturi nozzles (2o) formed in the wall of the Chamber (11) are attached, each of these slots having an enlarged entry portion (13) which extends into a restricted throttle and converges, wherein the Axis of the converging gas inlet part (13) and the throttle (3, 4) together linearly and significantly diverging extends from the particular direction on. 2. Device according to claim 1, characterized in that that the width of the slot at its narrowest point is 0.1 mm to 3 mm. 3. Device according to claim 1 or 2, characterized in that that the length of the throttle (3? 4) is 1 mm to mm » 4. Apparatus according to claim 1 or 2, characterized in that that the length of the throttle (3, 4) 2 mm to 4 5934-02 "1 " JI J> J 111 ti » t 1 9 - 13 - mm. 5. Apparatus according to claim 1 to 4, characterized in that the length of the ending at the throttle converging entry part (13) is 1 mm to 1o mm . 6. Apparatus according to claim 1 to 5, characterized in that the width of the throttle (3, 4) between approximately o, o2 mm and 3 mm. 7. Device according to one of claims 1 to 6, characterized in that the chamber (11) is cylindrical Has shape and consists of a plurality of coaxially supported annular components in the Abctand are arranged from each other and parallel to each other form a series of slots (2o) therebetween, the annular Components are contoured such that one annular component has a circumferential slot in the V / and of the chamber relative to the next adjacent annular component (11) forms with the enlarged gas inlet part, which extends into the restricted throttle and converged 8 "Device according to claim 1 to 7, characterized by a device (28) for. Premixing the scrubbing liquid with the gas stream. 9. Apparatus according to claim 1 to 8, characterized in that the inner chamber has a cylindrical shape and is formed from a plurality of coaxially supported annular members which are parallel to one another at a distance have and define slots (2o) therebetween, the annular components having an outline such that a - H annular component relative to the next adjacent one annular component has a circumferential slot around the wall of the Forms inner chamber having the enlarged entry portion that extends into the restricted throttle and converges. 1o. Device according to one of claims 1 to 9 »thereby characterized in that the predetermined direction im. is substantially parallel to the axis of the device.