DE2622484A1 - METHOD AND DEVICE FOR COOLING AND PURIFYING GAS - Google Patents

Description

DW -IN "DIPL.-IN3 M. SC D'PL P" Y ". DR. DI PL.-PHY ».

HÖGER - STELLRECHY - GRIESSBACH - HAECKER

PATENT LAWYERS IN STUTTGART

TECHNO'CHIM S. R. L. - MILAN - ITALY A 41 770 m

»Process and device for cooling and cleaning gas»

The present invention is a method and the corresponding device for Purification and / or saturation treatment of gases,

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especially of exhaust gases from metallurgical furnaces. As already known, the treatment systems of the

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Exhaust gases from metallurgical furnace can be divided into two categories:

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1) dry systems, and

2) wet systems.

In wet systems, an important stage is that of cleaning and / or saturating the gases with water, with two objectives as a basis for this treatment:

a) Cooling of the gases from temperatures of the order of magnitude of 1700-8OO ° C to values of 70-80 ° C;

b) Cleaning of the gases from larger particles and dust, which are carried away by the gases themselves.

In the systems implemented in practice, the mentioned process so-called saturators are used, which are normally designed according to the venturi or spray type are.

In the first type of saturator, the gas is introduced into the neck of a venturi, which is preferred

the saturation water is supplied by overflowing, whereby the gas and the cleaning water move in cocurrent.

If it is also possible, the volume of this device Keeping it within fairly low limits, the gas experiences relatively high gradient losses.

The spray saturators usually consist of empty containers of large dimensions, those at one end

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the gas to be treated is supplied, while the cleaning and / or saturation water is supplied by means of one or more spray nozzles in the manner of a hollow cone, which are arranged on the axis of the container. These nozzles usually form a conical jet and the gas is fed in from above or below, depending on whether the contact is to be made in cocurrent or countercurrent.

In this case the gradient losses are reasonable Limits are set, but there are other problems and disadvantages, such as the large amount of water that the saturator is to be supplied, the large space requirement of the device the cleaning difficulties of the nozzles, since they are arranged inside the device, they have to be removed beforehand, they come to light.

To ensure sufficient contact time between water and gas to achieve the specified results In order to obtain it, it is inevitable to enlarge the dimensions of the container very much. However the cross-sectional shape of the container is at the same time in practice the formation of dead areas, i.e. only little sprayed zones in which the contact between water and gas is insufficient and even zero is, inevitable.

In practice on an industrial level, it is necessary to supply large amounts of water to the nozzles,

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which can reach up to six times the amount that needs to be vaporized to achieve the desired result. In order to finally prevent the soiling and clogging of the spray nozzles, it is necessary to shut down the system in order to carry out the cleaning work, which is only possible after the nozzles have been removed from the device.

The main object of the present invention is to carry out the cleaning and / or the saturation with water of the gases, in particular the exhaust gases from me-

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metallurgical furnace, whereby the contact between gas and the water supplied in finely divided form takes place in countercurrent in such a way that the volume of the contact area and therefore of the device is substantially reduced, the ratio between Feed water and evaporated water is kept low, the gradient losses are kept low and the Dead areas in the space of the device are eliminated.

Another, equally important object of the invention is to provide a device for cleaning and / or saturating gases that are not only the meets the above-mentioned requirements, but also a continuous cleaning of the walls of the Saturator and the possibility ensures that the nozzles for supplying the water are free and clean without undue interruptions in the operation of the device to keep.

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ORIGINAL INSPECTED

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These objects are achieved with the aid of the present invention, which provides a method for cleaning and / or saturation with water of gases, in particular

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which of exhaust gases from metallurgical furnace provides, according to the type in which the contact between the fine distributed water and the gas to be treated mainly in countercurrent in a treatment area takes place, characterized in that the supply of water to said area in the form of Fan-shaped jets are made, each of which is bounded by a vertical V-shape, and from spray devices goes out, which are arranged in opposite places and at least along two edges of the horizontal cross-section of the treatment area are offset, the offset of said Spray devices is such that there are essentially no interruptions between two adjacent jets exist.

In the preferred embodiment of the invention Process in which gas is supplied from below opposite the treatment area and the spray devices mentioned spraying the treatment area mentioned from above, are dependent the active parameters as characteristics of the gas (i.e. type, temperature, flow rate, etc.) and of the water (i.e. the flow rate, the amount to be evaporated, etc.),

INSPECTCI *

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, the height of the outlets of the fan-shaped jets, the initial speed and the average size of the water particles forming each fan are chosen such that a predetermined proportion of the particles themselves is carried away by the ascending gas flow after they have covered a predetermined distance in free fall , so that essentially Extent the contact time between gas and water is increased .

In this case, of course, the fact that the particle size during of free fall due to gravity decreases through surface evaporation, reducing the choice of The initial size of the particles is reduced to larger values will judge than those for whom the above-mentioned entrainment takes place.

The device for carrying out the method according to the invention in turn sees a container, preferably in parallelepiped form, in front of that with a supply line for the gas to be treated at one end and at the opposite end with devices for spraying finely divided water is provided, this device also having an outlet for the treated gas and with an outflow of the water after contact with the gas and is characterized in that

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said spray devices are capable of fan-shaped Create rays, each of which is delimited by a vertical V shape and which are longitudinal two opposite sides of the horizontal cross-section of the container are arranged, wherein the spray devices generating the adjacent jets are opposite and mutually offset so that there are essentially no interruptions between the two adjacent beams.

In the preferred embodiment of the invention Device, the spray devices are designed in such a way that the nozzles can be cleaned without the operation of the device having to be interrupted, so that the incrustations and the pollutions, which result from the continuous flow of water, are removed and tend to prevent the regular and predetermined outflow of the water itself.

For this purpose, each spray device consists of a substantially cylindrical housing that be attached to the wall of the cleaning and / or saturation device forming container

π can, this housing having a first opening at the end, which faces into the interior of the container and in which a spray nozzle is located, a connection for feeding the pressurized water into

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Inside of the hollow housing, with those in the area

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the first opening arranged spray nozzle in such a way is that a fan jet as defined above is generated and comprises cleaning agents, the inside of the housing between a rest position, in which the free flow of water through the nozzle is allowed, and are slidable to a cleaning position in which they cover the entire inner walls claim and are in contact with the water from the said nozzle to remove the encrustations and the to remove dirt that has adhered to the walls itself.

In this regard, it has been found and this constitutes the optimal practice of the present invention it is possible to get a fan beam which has the features mentioned and in which a nozzle with an outflow hole circular Cross-section used when the nozzle consists of a substantially cylindrical block, which is traversed axially by an equally cylindrical bore, the two opposite ones Bases of this block with deep, diametrical, i.e. perpendicular to the axis of the cylindrical bore Millings or grooves are formed, these millings perpendicular to each other and in such a way .are arranged that the outflow side of the water from the through »hole in the block

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corresponding milling has an axial plane that coincides with the vertical plane of symmetry, which is passed through the edge of the V-shape delimiting the fan beam. It lies suggests that in this way the milling made on the opposite side of the block will be perpendicular to the edge of the mentioned V-shape.

The design of the bore for the flow of water in the one is essentially circular Cross-sectional nozzle has the very important consequence of any shape and / or position restriction to eliminate the cleaning agents, which can consist of a simple cleaning piston, the one Has circular cross-section, which is expediently designed to be smaller for the outlet bore of the nozzle.

The features and advantages of the present invention will become more apparent from the following detailed, exemplary, but not restrictive description with reference to the attached Drawings. In the drawings show:

FIG. 1 shows a vertical section of a preferred embodiment of the device according to the invention;

FIG. 2 shows a horizontal section along the line II-II from FIG. Ij

FIG. 3 shows an enlarged vertical section of a preferred spray device for the spray device according to the invention Contraption; - 9 -

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FIG. 4 is a side elevational view of the nozzle used in the sprinkler "of FIG. 3;

FIG. 5 shows a vertical cross section along the line V-V from FIG. 4;

FIG. 6 shows a plan view of FIG. 4 from above;

FIG. 7 shows a view, analogous to FIG. 4, of the nozzle rotated by 90 °;

FIG. 8 shows a plan view of the nozzle from FIG. A _{3 seen} from below, and

FIG. 9 shows a horizontal section of a variant with a circular cross section of the device Figure 1.

In Figures 1 and 2 is a device with a rectangular cross-section for cleaning and / or saturation with water from gases, especially from exhaust gases

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metallurgical furnace shown

As is known, these gases occur at a very high temperature and with particles of the constituents of the furnace

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batch a-n enriched from the furnace. These gases normally undergo an afterburning, the purpose of which is to drastically reduce the content of unburned substances, whereupon they are transferred to the cleaning operations after, as is obvious, a lowering of the temperature, starting from the values 1700 - 800 ⁰ C up to have experienced in the order of 70-80 ⁰ C temperatures.

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The device from Figures 1 and 2 consists of a rectangular cross-section pointing Container 10, which has an upper connection II for discharging the withdrawn and saturated Gases and a bottom outlet 12 is provided for the discharge of the non-evaporated water, which is with the particles are mixed up by the gases removed by the cleaning action.

For this purpose, a floor grate 13 is also provided, who has the task of holding back the larger particles. At the outlet 12 are natural Means not shown are provided in order to realize a water gradient in the bottom part of the container 10, that prevents gas leakage.

The gas is supplied via the connection 14 and the pipe 15, which has the task of to introduce the gas in a position that is central to the container 10.

The cleaning and saturation water is over, in generally indicated by the reference numeral 16 spray device fed.

As can be clearly seen from the two figures, the rays emerging from the devices 16 have a fan shape with a vertical plane of symmetry (indicated in FIG. 2 with the reference number 17), which are limited by a vertical V shape, so that only a natural expansion takes place , ever

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yreiter is the distance from the dispensing nozzle of the device is.

An essential feature of the devices 16 is that they are dimensioned and adjusted in such a way that the jet reaches the opposite wall of the container 10 with certainty, so that it is wetted, and that the amount and the atomization of the water are such that the entire volume defined by the aforementioned V-shape and the opposite wall of the container is sprayed .

It can also be seen from FIG. 2 that the devices 16 are expediently offset from one another in such a way that the beams emerging from the devices themselves do not interfere with one another but, on the contrary, are tangent to one another.

A separate consideration is the vertical position the devices l6 as well as the setting of the devices themselves, which determines the degree of atomization of the water and therefore the dimensions of the affects the particles of water that form rays.

Provided that the saturator depending on the amount, the speed, the density and the Temperature of the gas to be treated is dimensioned and therefore also the theoretical amount of water that is to be evaporated, is calculated, each drop of water thrown by the device 16 into the interior of the saturator.

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a) gravity and

b) subject to the counteraction of the rising gas flow.

On the basis of theoretical considerations and as a result of experimental results, it was found that that there is a diameter value of the water drop, in the range of which the drop itself after a certain descending distance, being carried upwards, with the clear desired result. · · one Increase in the contact time gas-water is achieved that, as is known, has a decisive importance for the purpose of the exchange of matter and heat. In practice the said value of the dimensions must depend on that of the water droplets descending along the Distance experienced by surface evaporation must be corrected.

Is then also taken into account the fact that the droplets ejected from a spray nozzle, normally have dimensions contained within a certain size range and that, as is obvious, the distance covered by the drops depends on the height at which the devices 16 are opposite are arranged on the grate 13 (if this is touched, the drops can obviously no longer rise), the principle on which the present invention is based is to determine the initial speed, the diameter of the drops and the height of the position

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of the devices l6 to choose within such a size range that no more than a predetermined proportion, preferably of the order of magnitude of $ 50 that emanates from each sprayer Droplets of water reach the bottom of the container.

In order to explain the advantages achieved by the above principle, a practical example is given below the gas states at the inlet of the saturator are shown:

Speed 15> 70 m / sec

Density 0.343 kg / m ³

Gas conditions at the outlet of the saturator: speed 7.62 m / sec

Density 0.904 kg / m ³

With an initial speed of the water droplets of about 35 m / sec and at a height of the saturator (calculated from the axis of connection 14 to the connection of the outlet of the gases) of 3.5 m with the change in the droplet diameter, the following values of the fall and rise times of the droplets, the Klarervfeise the contact times gas and water correspond:

Droplet diameter / V 600 900 1100

Fall time:

(to the rest point) Climbing time for 3.5m

0.144 O, 25th O, 34 Oj 60 O, 65 O, 70 IS

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• Based on the above data, it was possible to set the minimum values for the height of the spray devices calculate values that are as follows:

Drop diameter, u. 600 900 1100 Minimum height in meters 1.45 2.50 3.5

From the above, it is easy to see that when the spray devices are chosen to that a predetermined proportion of the jet droplets have an average diameter in the size range of 1100 microns and the devices themselves at a height not less than 3.5 meters from the grate 13, the total contact times of the mentioned proportion of drops (and therefore of the water) with the gas are approximately 0.34 + 0.70 = 1.04 seconds.

Would the same drops in cocurrent with respect to the gas with the same pressure at the nozzles and with spun at the same spin speed of 35 m / sec, the contact time would be (how easily calculable) less than 0.16 seconds.

If now the spray devices 16 considered in detail, as is seen in Figure 3, that they consist in derjbevorzugten embodiment of a hollow housing l8 which a correspondingly shaped seat 21 is fixed by means of einrr flanges 19 on the respective flanges 20, the the in the wall Container 10 is formed. The housing 18

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is provided with a side connection 22, which by means of a pipe 23 with a device 24 is connected to feed pressurized water.

In the interior of the hollow housing 18 is a scouring or. Cleaning element 25 slidably received, which at one end of the housing l8 by means of a handle 26 or a pneumatic control piston can be operated manually.

At the end facing away from that of the handle 2 6, carries the cleaning element 25 a scraper tip 27 which can penetrate into the bore of the nozzle 28, the is arranged at the end of the hollow housing 18 received in the interior of the seat 21.

The spray nozzle 28 held on the hollow housing 18 by means of a screw ring is shown in FIGS. 4-8 shown in more detail.

The spray nozzle 28 consists of a body or zy relieving shaped block 30, alignment of the, achsLal, two sections or cylindrical bases 32 and out, which have a smaller diameter than the K body 30 wherein an axial bore is provided in the spray nozzle 31st

A groove or milled recess 34 or 35 is provided in the area of each cylindrical section 32, 33. These two grooves are perpendicular to each other

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and have a width that is substantially corresponds to the diameter of the through hole.

On the basis of practical tests it was found that with a nozzle designed in this way, ie having a circular bore, a jet is obtained at the outlet which has an essentially flat fan shape and extends in a plane which is guided through the axis of the groove which is on the exit side of the block 28. The incision 37 has the task of receiving a corresponding projection of the body 18 for fixing the nozzle 28 in a predetermined position.

Without wanting to give a precise explanation of the behavior of the nozzle described above, was

It

in practice observed that the opening angle of the nozzle and the flattening of the jet essentially in one plane, at least in the vicinity of the outlet from the nozzle from the height of the vertically recessed on the other side (upstream) Depend groove.

In connection with FIG. 3, it is expedient emphasize that the spray devices 16 against

η inclined downwards, whereby for an opening angle of the fan jet of about 90-110 °, the jet itself not only wets the opposite wall, but also the wall 10 in which the spray device is mounted, whereby also a continuous

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and effective cleaning of the walls of the device is ensured.

Finally, FIG. 9 shows the implementation of the method according to the invention in the case of a cylindrical shape Container 36, for which, of course, the arrangement of the spray devices is expedient must be adjusted, not only in terms of height, but also in terms of alignment.

As an example, the fact can be mentioned that with your method according to the invention and the corresponding Device has been proven that it is possible to purify and saturate with water

ir of the exhaust gases from metallurgical furnace., without to experience the gradient losses normally encountered in the above-mentioned spray saturators and at the same time keeping water consumption at very low levels; a as a relationship The value expressed between the supplied water and the evaporated water, which is between 1: 1 and 2.5il lies.

Is taken into account that with the conventional spray rain saturators this ratio is usually on the order of 6: 1 and several tens of cubic meters Water are to be used for every operating hour, is the undoubted saving that with the help of the method according to the invention is achieved, high

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to assess. There is also the undoubted advantage of the reduced volume of the saturator forming the container and the equally important advantage of a distribution of the water jets, which acts on the entire volume of the saturator.

It is obvious that the scope of the invention also includes a reversal of the mutual arrangement of the spray

devices and belongs to the gas supply, whereby the countercurrent principle is retained.

In this case, namely, the spray devices are arranged at the bottom of the saturator (ie in the vicinity of the grate) and the gas is supplied at the top with a descending current. In this case the fan jets are thrown essentially upwards and once the kinetic energy has been exhausted the drops fall back together with the gas. It is obvious in this case that it is ensured that all the water particles cover a distance both upwards and downwards, even if the contact times of the individual droplets with the gas are below those of the aforementioned case .

Of course , the arrangement of the rays and, above all, the fan shape is also essential in this case.

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Finally, it is not excluded that in some cases the simple application of the arrangement of the spray devices with fan jets are sufficient is to carry out the desired gas-liquid exchange, even if this is in direct current he follows.

Ultimately, it goes without saying that modifications and variants that are in principle and structurally equivalent are, are possible and foreseeable and are considered to belong to the scope of the present invention will.

In this regard, it is useful to emphasize the fact that in the above description on the treatment of exhaust gases from metal

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lurgical furnace was referred to. However, this has not of a restrictive nature, especially since the method and the device of the invention are likewise can also be used satisfactorily in other cases in which a matter and / or heat exchange between a gas stream and a liquid.

ORIOlK ¹ AL.INSPECTED

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Claims (11)

26? > - _; 3A PATENT CLAIMS 1 «Process for cleaning and / or saturation of gases with a liquid, according to the type, in which the contact between a finely divided liquid and gas in a treatment area takes place, characterized in that the supply of the liquid to said Area takes the form of fan beams, with each beam bounded by a vertical V-shape is and emanates from spraying devices on opposite and longitudinally at least two opposite one another Sides of the horizontal cross section of the treatment area arranged staggered points are, the offset of the spray devices mentioned is such that between-η two there are essentially no interruptions to the adjacent rays. 2. The method of claim 1, wherein the contact between gas and liquid initially takes place in cocurrent, with the spray devices on one end of the treatment area and the supply of the gas to be treated at the opposite end End takes place, characterized * 21 - - ORIGINAL INSPECTED 609851/0721 2622 ^ 84 that the size of the ejected liquid, its initial spin speed and the distance of the spray devices from the opposite one The end of the treatment area should be selected in such a way that the kinematic energy of the liquid particles, at least for a predetermined proportion, becomes zero before the liquid particles Reach the opposite end of the treatment area where the treatment area is Gas is supplied. 3. The method according to claim 1, characterized in that the mentioned Cleaning and / or saturation liquid jets are dimensioned in such a way that in the horizontal (cross-section of the treatment area each beam to the opposite end of the area itself " extends. 4. Apparatus for carrying out the method according to claim 1, consisting of a container which with a supply line of the gas to be treated at one end and with Sp rest devices from. fine distributed water as well as with an outlet for the treated gas and with an outflow for the Provide liquid after contact with the gas - -22 - ORIGINAL INSPECTED 6098 5 1/0721 2622Ä84 is characterized in that said spray devices are capable of Generate fan beams, each of which passes through a vertical V-shape is delimited, and that said spray devices along two opposite sides Sides of the horizontal cross-section of the said container are arranged, wherein the spray devices, .the adjacent jets generate opposite and offset so that between the two adjacent beams im there are no significant interruptions. 5. Apparatus according to claim 4 * thereby characterized in that said container has a parallelepiped shape and said spray devices are arranged along two opposite sides of the container itself are. 6. Apparatus according to claim 4, characterized characterized in that said outflow of the liquid is intercepted by a grate sum is shielded from larger particles, which are separated from the gas to be treated by cleaning and in the case where the supply of the gas to be treated is in the lower part of the container takes place and the spray devices in the upper part π
of the container are arranged dia mentioned 60985 1/072 1 262: ^ 84 Sprtthvorrichtungen arranged at such a height from the inlet mouth of the gas are that for a given size and initial velocity of the treated liquid particles and a given velocity and Density of the gas to be treated, at least the kinetic energy of the liquid particles mentioned becomes zero for a predetermined proportion before the liquid particles reach the inlet cross-section of the gas. 7. The device according to claim 4, characterized in that said Spray devices are arranged such that part of the fan jet generated by each device the adjacent wall of the container on which the device itself is attached Wetting applied. 8. Apparatus according to claim 4> thereby marked that any spray device from a substantially zyliriderf örmigen. Hollow housing is made on the wall of the device self-forming container is attached, this hollow housing a first at the end of the ins Inside of the container facing housing provided Opening in which a spray nozzle is located, - 29 - ORIGINAL INSPECTED 609851/0721 262 .: v3 a connection for connecting the interior of the hollow housing, the in the area of the first Opening arranged spray nozzle is such that a fan-beam is generated as previously defined, and having cleaning means which is slidable inside the hollow body between a rest position in which the free drainage is the water between said nozzle and a cleaning position allowed, and a cleaning position , in which this cleaning agent hits all inner walls and is in contact with the water from the nozzle mentioned in order to remove the incrustations and the dirt adhering to the walls themselves. 9. Apparatus according to claim 8, characterized characterized in that the spray nozzle consists of a substantially cylindrical block exists, which axially traverses through a through hole having a circular cross-section wherein the two opposite end portions are formed with a semicircular cross-section having grooves which have substantially the same diameter as the said through hole, said grooves being perpendicular to one another. 10. Apparatus according to claim 9j thereby ■; ..- 25 -. . ■ ORlQiNAL INSPECTED 6 0 9 8 5 1/0 7 2 1 ' characterized in that said nozzle is arranged so that the axis of the on the outflow side of the liquid arranged grooves in the vertical plane of symmetry of the vertical V-Forin lies, which is the said fan jet specifies. 11. The device according to claim 10, characterized characterized in that means for fixing said nozzle in the desired Location of the groove are provided, which is arranged on the outflow side of the liquid. 609851/0721 -eft. Blank page