DK149647B - PROCEDURE AND PLANT FOR TREATMENT OF ROEGGAS IN CONNECTION WITH THE MANUFACTURE OF LUNTERS, FLOOR COATS OR MATERIALS OF MINERAL FIBERS - Google Patents

Description

149647

The invention relates to a method for treating flue gases in connection with the manufacture of articles, such as lintels, floral webs or mats of mineral fibers, in particular glass fibers, in which the fibers emanating from a plant for drawing fibers by gas streams are applied a binder containing pollutants and then passed to a receiving means by which the fibers are separated from the total flue gas stream including the draft gas stream, the air or gas streams induced by it, and the pollutants entrained, and said total flue gas stream after passage through the fiber blank and the receiving means are purified with water so that the flue gas stream is simultaneously cooled vigorously.

For such a preparation, binders containing pure or modified phenolic resins or aminoplastics are usually employed because they exhibit advantageous properties in the manufacture of products of agglomerated fibers. These substances are thermosettable and soluble or water-soluble, 20 adhere well to the fibers and are relatively inexpensive.

Usually, these binders dissolved or dispersed in water are used, which are added to various substances to form the adhesive that is atomized on the fibers.

25 During the heat stress to which they are subjected during the manufacturing process, these substances emit volatile and toxic elements which have a pervasive odor in even very small concentrations. This is for example. on phenol, urea, ammonia and 30 organic decomposition products.

For some purposes, other binders are used which are very cheap. Various extracts of natural products are cured by crosslinking. This is for example. about linseed oil which is oxidized. Other products, such as bitumen, are thermoplastic. During the process of bonding the fibers, all of these products are at least partially exposed to a sufficient heat effect to emit volatile elements which are bothersome, in particular because of their odor.

In the following description, the term "binder" is meant to mean any substance or mixture of substances of the kind mentioned above, either in liquid form, in dissolved form or in the form of a slurry in water or other liquid or in the form of an emulsion. .

The invention relates to the part of a plant for the production of products of agglomerated fibers, the so-called receiving part, located immediately after the fiber-producing organ, and in which substantially the following operations take place.

The fibers are transferred from the fiber-making means to the means where the mat is provided.

- The fibers are glued together by means of the binder which usually releases pollutants.

- The mat is provided on the receiving means, usually constituted by a perforated conveyor belt.

20 - The fibers and the tensile and guide fluid are cooled, usually by means of the air flow induced by the fluid.

The fibers are separated from this fluid and from the air by passage of the fluid through the mat provided.

- All elements that are not retained by the fiber mat are routed away from the plant.

It is in the receiving portion that large quantities of gas and water come into contact with the binder containing pollutants, thereby being contaminated in a process common to the existing methods of making lintels, flooring sheets or mats of agglomerated fibers. This pollution process must now be described in more detail.

35 a) The pollution of the gases is as follows.

The binder is atomized in the flow of fibers and fluid emanating from the fiber-producing member, forming a cloud of small droplets. Part of this binder is captured by the fibers. Some are deposited on the walls of the plant. Some are found in the form of small droplets or vapor in the flue gases.

Therefore, at one time there is a double cause of 5 pollution, namely because of drops of the binder and because of vapors from the binder. Nozzle for atomizing the binder releases droplets of quite different dimensions. The very small droplets are not intercepted by the fibers and pass through the fiber mat 10 along with the current which brings the drops with them.

The droplets which, during the application of the binder, are captured by the fibers are subjected to the kinetic influence of the flow, whereby a large amount of droplets are torn from the fibers, migrate through the mat and recover the slurry 15 in the outgoing fluid.

The desire for a homogeneous distribution of the binder in the fiber mat implies that the binder must be atomized in the flow of fibers and fluid in a region adjacent to the fiber-producing member, at the location where the flow still has a well-defined geometric shape, but where its temperature is sufficient to evaporate part of the binder or at least some of its most volatile constituents. These pollutant vapors are mixed with the fluid and contaminate it.

In the following description, the term "flue gases" means the gases which penetrate through the fiber mat and are directed away from the receiving portion, ie. the mixture of the drawing and controlling fluid, the fluid thus induced and the pollutants contained in these droids in the form of small droplets or of vapor.

b) The water used in the receiving section causes severe pollution.

The water is used to: 35 - dilute and transport the binder when it is - used in liquid form.

- cleaning the flue gases, which involves letting water droplets capture as much of the pollutants as possible, whether they occur as droplets or fumes in the flue gases, so that these substances are transferred from the flue gases to the purified water, and between the walls of the receiving section to intercept and carry the fibers contained in the flue gases.

5 - cleaning the various parts of the receiving plant e.g. the perforated conveyor belt, the flue gas lines, thereby removing the binder and fibers deposited on these parts.

During these operations, the purifying water absorbs the 10 soluble or insoluble binder constituents or vapors thereof, and its concentration of pollutants can reach high values.

The above explanation of how the flue gases and water are polluted is based on 15 measurements and studies in existing plants. This information is intended to serve as an explanation only and other reasons may be adduced without prejudice to the present invention.

In all plants for the production of fiber products, 20 and whatever fiber-forming principle is used, this contamination process involves large quantities of flowing fluids.

In plants equipped with means for drawing fibers by blowing, and in which the material to be drawn is converted into fibers under the influence of high energy gas streams, fumes are emitted in the atmosphere by the known methods, in the following orders of magnitude: 3 - 100 Nm per kg of fiber by the method described in U.S. Pat. No. 2,133,236, 3 to 300 Nm. kg of fiber by the AEROCOR method, cf. US Patent 2,489,243.

3 - 70 Nm per kg of fiber by the SUPERTEL method, cf. FR patent 1,124,489.

35 In a factory of considerable size, 3 will thus achieve a flue gas volume of 500,000 to 1,000,000 Nm / h.

In plants equipped with fibers for drawing fibers, the material to be drawn is converted by mechanical action, e.g. centrifugation, and where the gas stream is used only for transport, usually in a horizontal direction, of the fibers to the receiving means, the amount of flue gas is slightly smaller, but quite large, e.g.

3 5 30 Nm pr. kg of fiber by the method described in US. U.S. Patent 2,577,431. In a factory this will lead to the emission of flue gas of approx. 300,000 to 400,000 Nm / h.

By all these methods, the amount of contaminated water is almost the same, viz. 1000 m / h, even at 10 large plants.

The magnitude of these quantities of pollutants has led to legislation trying first to limit the content of phenolic compounds in the flue gases in the atmosphere and then, at least in some countries, to prohibit the release of pollutants. In addition, in different countries, there is a demand for a reduction of odor and opacity in the released polluted flue gases.

The plants for producing agglomerated fiber products also provide a strong nuisance in this regard, in addition to the release of toxic and odorous substances, they also release large amounts of water vapor -ca. 20 to 30 h / h in large plants - emitted to form opaque fumes.

The noise is also a disadvantage of installations of the kind mentioned here. In such plants, the noise essentially comes from two sources of noise, namely the fiber-producing means and the fan for removing the flue gases.

The fiber-producing means included in such plants employ to convert the material to be drawn into fibers, or to control the flow of fluid at high velocity. It is known that the noise level at such streams increases sharply with the flow rate and in the vicinity of the fiber producing means, i.e. where the staff of 35 works, the noise level can be 100 dB. This level is above the statutory value.

149647 6

The noise from the fan propagates along the pipelines leading the flue gases to the chimney and this chimney, located outside the factory building, acts as an antenna and spreads the noise in the neighborhood. The resulting 5 environmental nuisances have caused the authorities in some countries to demand the closure of individual plants.

The need for a reduction or suppression of the pollution at a relatively cheap price so as not to affect the price of the finished product too much is becoming more and more evident.

In view of these considerations, the invention aims to release to the atmosphere as small an amount of exhaust gas as possible in order to reduce as much as possible the amount of gas to be completely cleansed of pollutants, since such a complete purification is a right expensive operation.

To this end, the process according to the invention is characterized in that most of the water-purified flue gases are recycled to generate the draw gas stream or to be used as a complement to the draw gas quantity used during its flow to the receiving means and a flow of the water purified flue gases corresponding to the gas stream introduced into the plant 25 are purified of pollutants and discharged to the atmosphere.

The flue gases collected under the fiber receiving means, as mentioned earlier, carry fiber particles and droplets of binder which tend to form in the pipelines nuisance deposits which are later difficult to remove. During the purification, a significant portion of these particles and droplets are removed.

At the same time, a large amount of heat is removed from the contaminated flue gases, and by the recirculation of the flue gases, it is thereby possible to better control the temperature of the fiber drawing process and thereby prevent the hardening of the binder. A consequence of this is that one also gets an easier and better calibration of the fiber product, especially when it comes to a mat.

The invention also relates to a plant for carrying out the method according to the invention, which plant is of the kind comprising a means for making fibers, a chamber surrounding the flow of fibers between the fiber making means and a fiber receiving means to which the fibers are deposited to form the fibers. a fiber blank having a chamber entrance opening for a draft gas stream containing the fibers with applied binder and pollutants, and for the air or gas streams induced by the draft gas stream, and means for purifying and simultaneously cooling the flue gases with water after 15 their passage through the fiber blank and the fiber receiving means, and according to the invention is peculiar in that said flue gas cleaning means include means for contacting the flue gases with the purifying water, located on the downstream side of the receiving means relative to the flue gas direction, and in a recirculation circuit. separator arranged for separating the water from the flue gases, and a pipeline for returning at least a portion of the water purified flue gases to the chamber, and a second pipeline conducting a portion of the 25 water purified flue gases into the atmosphere through a flue gas purifier.

A system thus designed proves to be very effective in carrying out the process.

The invention will be explained in more detail below with reference to the schematic drawing, in which fig. 1 shows a receiving plant of the kind to which the invention refers; FIG. 2 is a part of the embodiment of FIG. 1, wherein the walls of the receiving chamber are extended up to the fiber-producing member; FIG. 3 shows an embodiment of the system according to the invention; FIG. 4 shows another embodiment of the system according to the invention; FIG. 5 shows an embodiment of the cleaning chamber; FIG. 6 is a complete system according to the invention for the manufacture of glass fiber mats; FIG. 7 is a plant according to the invention, intended for a different fiber-making process; FIG. 8 is a plant according to the invention, intended for a fiber-making process with blowing, and FIG. 9 is a plant according to the invention, intended for use in the production of mineral fibers, in particular slag fibers.

FIG. 1 shows a plant of a kind known per se in which the invention can be advantageously utilized. This plant 20 comprises the following parts: - A fiber-producing member 11 of a known kind, i. of the kind commonly used in plants for the manufacture of panels of agglomerated fibers, and in which the material to be drawn is subjected to the influence of a centrifugal force or an aerodynamic force or a combination of such forces. The aerodynamic force is applied to the material to be drawn or the fibers by means of gas streams usually having a high temperature and a high velocity.

The fibers obtained leaving the member 11 are dispersed in a gas stream 12 including high energy streams and currents which they induce in the surrounding environment, which stream encloses the fibers forming a bundle of well-defined contour, which fiber bundle is fed to -35 the roof body.

A zone for applying adhesive which is located in the path of the flow of fibers and fluid, between the fiber-producing member 11 and the receiving member, and wherein nebulizing nozzles 13 atomize the binder into small droplets in the flow of fibers and fluid. . A substantial portion of the droplets hit the fibers and adhere to the fibers, while the remaining portion forms a suspension in the fiber-bearing gases, either in the form of droplets or in the form of steam.

10 - A distribution means 14 for distributing the fibers, which means is arranged in the flow 12 of fibers and gases, either between the fiber-making means 11 and the zone for applying adhesive or between this zone and the receiving means, cf. 1. By means of this distributor means, the flow of fibers and gases can be given a swinging motion or deformed, whereby the fibers are distributed over the receiving means in such a way as to form a mat having a substantially constant weight per minute. unit area.

20 - A receiving member 15, consisting of a perforated straight, endless conveyor belt, on which the fibers are deposited to form the mat.

- One below the conveyor belt and in the area where the fibers are deposited and where the mat is provided chamber 16, in which is provided by means of a fan 19 a vacuum which forces all the gas supplied with the fibers in their web from the fiber-producing member 11 for the band 15 to pass through the mat provided in such a way that the fibers do not carry gas outside the area where the mat is provided.

Vertical walls 21 extending from the strip 15 upwards to a location in the immediate vicinity of the fiber-producing member 11, defining the area 35 where the mat is provided in such a manner as to form a space 22 enclosing the flow of fibers and gas, is open at the top of an area near the fiber producing member and forms a so-called receiving chamber.

A fan 19 whose function is to ensure that in chamber 16 a sufficient negative pressure 5 is obtained to force all the gas supplied with the fibers as they are deposited on the receiving means to pass through the mat provided and to to transport the gas out to the atmosphere through a chimney 5.

10 As mentioned earlier, by a roof system of the kind described here, large quantities of gas are developed. In the fiber-producing organs included in such plants, where the material to be processed is drawn and controlled, and the obtained fibers are controlled using fluid streams, there are large flow rates and velocities of usually more than 100 m / m. sec., i.e. considerably greater than the rate to which the fibers and gas must be communicated upon arrival at the receiving means, and which are usually not much greater than a few times 10 m sec. Therefore, it is necessary to significantly slow down the speed of the streams emanating from the fiber producing body. This is achieved by transferring the amount of motion from these streams to the fluid through which they pass and in which they induce currents which are accelerated in the flow direction and mixed with the incoming stream. It is this mixture of streams from the fiber-producing means and induced streams that form the outgoing gas stream that accompanies the fibers.

The induction of the flow from the fiber-producing member into the surrounding fluid is a well-known phenomenon characteristic of any flow in air or in a chamber containing a fluid. From 35 fluid mechanics, it is known that such a flow induces currents in the surrounding fluid and that these induced currents grow by the amount supplied per minute. unit of time and the extent of flow in the surrounding fluid. However, the induction phenomenon is a progressive phenomenon, and the decrease of the velocity 5 of the inducing current only reaches a significant value after the current has traveled a sufficient distance in the surrounding fluid.

In order to achieve a velocity for the flow of the fibers and gas at the above-mentioned value, i.e. at the receiving means, at the receiving means, equal to or less than a few times 10 m sec., the current flow from the fiber-producing member 11 to the receiving member 15 must extend over more than 2 to 3 m, and the fluid amounts of the current from the fiber-producing member 11 induce in this stretch, which must passing through the receiving member 15 is 10 to 20 times greater than the amount of fluid in the stream flowing from the fiber-producing member 11.

In addition to the braking to be communicated to the fibers 20 and the accompanying gas flow, it is necessary for the mat to be provided under good conditions that the directions of the flow of the fibers and the gas flow are mutually parallel and parallel to the principal direction from the fiber producing member to the receiving member.

For the sake of clarity, the flow conditions in successive sections must be considered through the flow 12 of fibers and accompanying gas, which section is indicated by section lines Μ, N, 0, P .....

The above implies that the current in each region, e.g. bounded by the intersection lines M and N

retains its direction and is subjected to a given speed decrease.

In each of these regions, these two factors, namely, the direction and the velocity decrease, obtain the desired values if the current is able to uniformly induce the required amount of fluid proportional to the product of the mass of the region over the entire periphery of the region. fluid forming the stream at the entrance to that area at the cut line M with the decrease of the relative velocity to which the stream is exposed as it passes through the area Μ N.

This decrease in the relative velocity is equal to the difference between the current velocity at passage past the intersection plane M and the output velocity as the current exits the intersection plane N, seen in relation to the input velocity.

If the ambient fluid is capable of delivering for each of all regions between the fiber-producing member and the receiving member the required amount of fluid and current braking to obtain the desired values, an induced fluid flow along the flow of fibers and accompanying gas will be provided. from the fiber producing means to the receiving means. In FIG. 1, this flow is indicated by streamlines 27.

20 In a plant of the embodiment shown in FIG. 1, the entire atmospheric air induced fluid of the flow 12 consists of entering the chamber 22 through its aperture 28, which has large dimensions and is located in a region in the vicinity of the fiber-producing member 11.

FIG. 2 shows the configuration of the fluid flow in a receiving chamber when the surrounding medium is unable to dispense all of the fluid which the currents produced by the fiber producing means can induce.

This configuration is given only as a contribution to the explanation given here.

FIG. 2 shows a part of a plant comprising a fiber producing means 11, from which a stream 12 of fibers and gas, a means 13 for applying adhesive, a means 14 for distributing the fibers, a receiving member 15 and a suppressing chamber 16 for collecting flue gas 29 passing through the mat 23 provided. All of these elements are identical to those of FIG. 1. However, the walls 21 forming the receiving chamber 22, cf. 2, extended upwardly to the fiber-producing member 11 in such a manner as to obtain a significant reduction of the opening 28 which connects the chamber 22 to the atmosphere, and thus also a considerable reduction of the amount of atmospheric air entering. in the chamber.

10 If the surrounding medium is in any region of the stream 12 and especially in the regions such as the region Μ N which is closest to the fiber producing member 11, i.e. closest to the nozzles for the flow for controlling or pulling the material, ie. at the point where the flow velocity is greatest, unable to dispense to the flow 12 the entire amount of fluid that can be induced, it is the subsequent regions, e.g. the region OP in the stream 12, where the flow rate is lower, which gives off the lack of fluid.

Gas streams 30, which originate from the lower regions of the main stream, creep up along the walls 21 towards the areas where the velocity is greatest, where they are intercepted by the main stream and accelerated in its flow direction. This produces vortex streams 31 which develop between the interface of stream 12 and chamber walls 21. The strength of these eddy streams grows with the amount of fluid that the surrounding medium has been unable to provide. These eddy currents circulate in such a way that they tear fibers away from the mat 23 provided and transport these fibers upwardly along the walls 21 of the chamber toward the distributing means 14, the adhesive application means 13, or the fiber making means 11.

It can be seen from the foregoing that if the amount of atmospheric air entering the receiving chamber in 149647 14 is reduced, the strength of the vortex streams 31 is a facility of the type shown in FIG. 1 and 2 to a value considerably less than the amount of air that the flow can bring may be sufficient for the fibers which they carry to settle on the means 5 for distributing the fibers and applying adhesive, thereby interfering with the functioning of these organs. In addition, the eddy currents cause disorder in the mat 23 provided, cf. 2nd

The industrial utilization of plants of this kind 10 proves that this retraction of the fibers is acceptable as long as the air flow entering the chamber is not less than 60-70% of the required amount. Below this value, industrial operation is no longer possible.

If an attempt is made to reduce even more or possibly abolish the amount of atmospheric air entering the chamber, the eddy current formation in this chamber may be such that the fibers can no longer be deposited on the receiving means.

FIG. 3 shows an arrangement for carrying out the method according to the invention. The receiving chamber 22 is closed at the top by a lid 32 which has an opening through which the flow 12 of fibers and accompanying gas from the fiber-producing member 11 enters 25 into the chamber 22. The edges 33 of this opening engage the flow 12 and have such a profile. , that the current can easily pass through the opening. For convenience, the lid 32 may be spaced H from the fiber-producing member 11.

30 The FIG. 3 comprises a cleaning vessel 17 located after the vacuum chamber 16 and having substantially larger cross-dimensions than this chamber. This vessel is provided with means by which the flue gas 29, i.e. the gas accompanying the fibers from the fiber-producing member 11 to the receiving member 15, as well as the contaminants in suspension 15, are contacted with a cleaning liquid, in particular water. In this vessel 17, the flue gases are cleaned of the particles, which mainly consist of fibers and the binder which the fibers absorb as they pass through the area where the binder is applied and through the provided mat. Upon contact with the water, the fibers present in the flue gases capture water droplets and, therefore, by gravity, tend to settle into the bottom of the vessel 17, which incidentally is accelerated due to the steep decrease in the velocity of the flue gases due to the variation of the cross-sectional dimension. upon transition from chamber 16 to vessel 17. Some of the pollutants in the form of droplets or vapor are captured by the water droplets and dissolved in them.

15 It is the combination of these two operations that forms the purge of the flue gases. The water used for the purification, which has taken over some of the pollutants from the flue gases, is discharged through an outlet 24.

The arrangement shown also comprises a cyclone or electrostatic type separator system 18 located between the cleaning vessel 17 and the fan 19, in which the flue gases are at least partially cleansed of the water droplets which they have taken over during the cleaning operation and which must be removed before the flue gases enters the fan 19. The purification water separated from the flue gases is discharged from the separator system through an outlet 25. A collector 26 directs the purification water from the outlets 24 and 25 to a treatment area.

The flow of fibers and accompanying gas passes through the means 13 for application of the binder and through the distribution means 14. The fibers are deposited on the receiving means 15, and the flue gases 29 penetrate through the provided fiber mat 23, the chamber 16, 35 the cleaning vessel 17 and the water separating means 18 and by means of the fan 19 is fed into a pipeline 149647 16. 34. A portion of the flue gases is discharged from the system through an opening 35. The remaining portion is passed over the conduit 34 to the receiving chamber 22, where they penetrate through an opening 36 located in the immediate vicinity of the fiber-producing member 11.

The amount of gas entering the receiving chamber through the aperture 33 is equal to the sum of the amount of gas emanating from the fiber-producing member 11 and the amount of air 27 induced during the transport of the fibers 10 in free air above height H. the amount of gas entering the chamber therefore increases with height H.

In order for this system to be in equilibrium, it is necessary that the amount of flue gases discharged from the system through the outlet opening 35 is equal to the 15 amount of gas entering the system through the opening 33. Therefore, the amount of flue gas will decrease as the height H decreases.

FIG. 4 shows a particular embodiment of the system according to the invention, in which the height H is reduced to 20 zero, i.e. wherein the fiber producing means 11 or at least the output nozzles of the drawing and controlling current are located within the chamber 22. In this case, the amount of pipe gas to be discharged from the system is approximately equal to the amount of fluid resulting from the fiber producing organ 11. In this embodiment, the proportion of recycled flue gases can reach values of 96-97%.

In systems according to the invention and as shown in FIG. 3 and 4, and where the recycled fumes of gas correspond to those which can induce the flow from the member 11, the fluid flow in the chamber 22 is generally in the direction of flow of the drawing stream and without the formation of disturbing eddy currents. The recycled flue gases essentially follow the streamlines designated 37.

17 U9647

One of the advantages of these plants is due to the fact that through the fan 19 the streams 37 of recycled flue gases can be given a slightly higher velocity than the streams 27 of atmospheric air, which the stream 12 of fibers and accompanying gas induces in the installation of the FIG. 1 art. The currents 37 therefore contain enough energy to counteract any fiber retrieval.

One of the major advantages of the system described above is that the amount of flue gases discharged from the system is only 3-4% of the quantities usually discharged and the order of magnitude given above, why It is possible to subject such a small amount of flue gases to a costly but effective treatment.

The flue gases exiting through the opening 35 are treated by combustion, which consists in bringing the flue gases to a temperature above 600 ° C, at which the pollutants of the flue gases, in particular the phenol compounds, are converted to non-pollutants such as CO2 and I by combustion. ^ O. This treatment also has the advantage of removing the odor.

This combustion takes place in a member 38 of a kind known per se including a combustion chamber 39, a burner 40 which is fed with a combustible mixture, and a member 41 of a kind known per se for stabilizing the flame. The treatment temperature can be reduced to values between 300 and 400 ° C when combustion catalysts are used.

The purified flue gases are diverted to the atmosphere through the chimney 42. At the exit of the chimney 42, the temperature of the flue gases is sufficiently high and the amount of flue gas emitted - due to the recirculation - is sufficiently low that the 35 vapor contained in the flue gas is not condensed dissolves in the atmosphere. No opaque smoke vortex is formed at the exit from chimney 42.

A further advantage of the invention lies in the fact that, since they are recycled and subjected to a treatment for total purification, the flue gases need not be subjected to a very extensive purification beforehand, thereby reducing the dimensions and costs of the purifier 17 and the water separator 18 which is located in front of the fan 19.

The above described and in FIG. The 10 systems shown in 3 and 4 comprise a receiving chamber 22 which surrounds the means for applying the binder and for distributing the fibers, which is why they are not readily available. However, while the apparatus is in operation, it may be desirable to engage the member 13 or member 14, 15 and for this purpose one has to open control windows in the walls of the chamber in an area adjacent to the fiber-producing member 11.

If, during such an operation, one wishes to avoid recycled flue gases, ie. If not completely purified 20 flue gases emit from chamber 22, the pressure in this chamber must be equal to atmospheric pressure or be a few millimeters of water column, for example 1-2 mm, under this pressure.

Furthermore, when the inspection members are closed, this allows to avoid any unwanted leakage due to the lack of close closure. The pressure in the chamber 22 is set to the desired value by adjusting the negative pressure provided in the chamber 16 by the fan 19 at a system constructed as shown in FIG. Third

Another way in which this can be achieved is to reduce the amount of flue gases to be discharged directly from the chamber 22 through an opening 43 in the chamber walls in the area where it is necessary to maintain the pressure of the desired value. instead of extracting the flue gases from the recirculation tube 34, cf. 4. The flue gases are discharged from the chamber 22 by means of an auxiliary fan 44 and through a pipeline 35. In this case, the fan 19 acts only for recirculation of the flue gases. This embodiment allows for a more precise localization of the area where a weak vacuum is present or a pressure equal to atmospheric pressure is maintained.

One of the characteristic features of the invention is that one can regulate the amount of binder delivered by the nozzles 13, depending on the amount of binder components suspended in the recycled flue gases and deposited on the fiber mat as the flue gases 10 pass through.

The recirculation causes the flue gases to pass several times under the provided fiber mat, and although the mat's ability to capture the binder is rather poor because the velocity of the flue gases is small, the number of successive passages is -ca. 15 pr. mine. such that a not insignificant portion of the binder components which are suspended in the flue gases are retained in the mat. This allows, to a similar extent, to reduce the amount of binder 20 to be atomized by means 13, whereby as regards the consumption of binder, an improvement of 5% is obtained, which is economically a negligible advantage.

In a plant of the type shown in FIG. 1, it is necessary to maintain a given temperature in the receiving chamber 22, and for this purpose the heat carried by the material and the drawing and control currents must be dissipated. As the binder used for bonding the fibers is thermoset, it is subjected to a continuous change during heat operation which progressively brings the binder from the liquid state in which it is atomized to solid state. If the temperature in the chamber 22 is too high, the binder during the mating can change so much that its binding capacity 35 is impaired. This phenomenon, called hardening, is avoided by cooling the receiving chamber 22.

149647 20

In the embodiment shown in FIG. 1, this cooling is achieved by the induced atmospheric air, which usually has a temperature below the maximum temperature desired in chamber 22. The amount of heat that the material and the drawing and control currents bring into the chamber, is of the order of 1500 - 15000 kcal. per. kg of material depending on the fiber forming methods, and this amount of heat is transferred by mixing with the induced air flow and then by mixing with the flue gases which transfer a smaller part of the heat to the purified water when in contact therewith, while the remaining portion is conducted. away to the atmosphere.

In the embodiment shown in FIG. 3 and 4, only a very small amount of heat is removed, since only a small volume of flue gases is discharged into the atmosphere, and therefore the receiving chamber 22 must be cooled in another way.

In accordance with the invention, this is achieved by transferring at least a portion of the heat, material, and drawing and control currents into the chamber 22 to a heat absorbing fluid, in particular water, the flow of fibers and accompanying gas or the flue gases. be brought into contact with this fluid. After the absorption of the heat brought into the chamber 22, the fluid 25 is directed away from the chamber and cooled by a suitable system located outside the system.

The heat exchange between the flow of fibers and the accompanying gas or the flue gases and the cooling water occurred either by direct contact or through a heat conducting partition. It is known that the amount of heat exchanged in such a transfer method is proportional to the temperature difference between the fluid to be cooled and the cooling fluid and with the contact area.

Given the dimensions of the plant, the relatively high velocities of the gas or flue gases mean that there is only a short time for heat exchange.

Therefore, in order to obtain sufficient cooling, large quantities of heat per exchange must be exchanged. unit of time.

149647 21

For this purpose, a method is based on extracting from the receiving chamber 22 the heat carried by the material and the drawing and control currents by cooling the flue gases in the chamber 16 and the vessel 17, ie. at the 5 point where the dimensions allow for establishing large contact surfaces between the flue gases and the cooling water.

The large contact area can be obtained in several ways: either by dispersing the water in the form of fine droplets or by running the water as a thin film or by bubbling the flue gases into water.

For example, FIG. 3, spray nozzles 45 are used which disperse the cooling water in the form of blankets of small water droplets which are located substantially perpendicular to the outflow direction of the flue gases 29. After passage through the provided fiber mat, the flue gases enter the chamber 16. temperature of approx. 80 - 100 ° C and upon contact with the cooling water the temperature drops to approx. 30 ° C. The water at the entrance to the nozzles 45 has a temperature of approx. 15-20 ° C depending on the design of the cooling means. Upon contact with the flue gases, the water is heated to a temperature of approx. 30-40 ° C depending on the amount of water delivered from the nozzles 45.

The amount of cooled flue gas recirculated after passage 25 through the separator 18 and the fan 19 enters the receiving chamber 22 and mixes with the gas emanating from the fiber-producing member 11, thereby cooling this gas and the fibers in the same manner as the atmospheric air does. that shown in FIG. 1 shows 30 plants.

Pig. 4 shows a further embodiment of the plant, where the cooling water flows over plates 46 and forms a thin film on these plates. The flue gases 29 flow along these plates, coating the water film 35 and thereby cooling.

149647 22

FIG. 5 shows yet another embodiment of the plant.

In this embodiment, the flue gases flow out through the aperture 47 below the surface of the amount of water contained in a vessel 48 located in front of the negative pressure chamber 16, thereby producing a powerful bubbling inside the water and beyond the apertures 47, of flue gas provides a large contact area between flue gas and water.

Another method is to remove from the receiving chamber 27 10 the heat carried by the material and the drawing and control fluid by directly cooling the stream 12 of fibers and gas by atomizing water in this stream. The water is atomized in the stream in an area where the contact area is not quite large, since the space available is small, but where the temperature difference between the fluid to be cooled and the cooling fluid is large.

For this purpose, various embodiments may be used. For example, FIG. 3, nozzles 49 are arranged between the fiber-producing member 11 and the member 13 serving to apply the binder so that fine water droplets are injected into the stream to be cooled.

These water drops hit the gas and fiber stream in an area where this stream has a high temperature which can reach up to approx. 600 ° C so that the water is evaporated immediately.

The rather large amount of heat, approx. 650-700 kcal per about 20 kg of evaporated water needed for evaporation of the 30 drops of water is taken off from the fiber and gas stream, thereby exposing this stream to a rapid cooling which has decreased to a value of approx. 100-120 ° C. The water vapor developed here is removed together with the flue gases through the fiber 35 mat 23, the chamber 16 and the vessel 17, where upon contact with the water rugs from the nozzles 45, it condenses and transfers its heat to the cooling water from the nozzles 45.

149647 23

The arrangement of the means 49 for spraying cooling water against the flow 12, i.e. between the fiber making means 11 and the means for applying binder constitutes the preferred embodiment of the plant since it exhibits the following advantages:

It is in this area that the temperature difference between the current to be cooled and the water is greatest and where the heat transfer is therefore greatest.

The spraying of the binder on a cooled stream of fiber and gas occurs at a sufficiently low temperature (100-12 ° C) to limit or avoid deterioration of the binder by evaporation of volatiles. As a result, the efficiency of the binder is improved by 5% and a correspondingly lower pollution in the flue gas is obtained.

FIG. 4 shows another embodiment in which the cooling water atomizing means 50 is arranged on the fiber and gas flow 12 between the binding agent means 13 and the receiving means 15. In the same way as in the embodiment shown in FIG. 3, the cooling water passes in the form of steam through the provided mat 23. The water is condensed and transfers its heat to the water films flowing over the plates 46 in the wash chamber 17.

This water is diverted from the plant through openings nos 24 and 25 in the lower part of chamber 16 and vessel 17, respectively, and from water separator 18 to a means 51 in which the water is purified of solid particles and in particular fibers.

The member 51 may be a vibrating or rotating mask filter of a kind known per se or a decanter or centrifuge.

The purified water is collected in a vessel 52 and from there, either under the influence of gravity or by means of a pump 63, is passed on to a cooling station 54. From the outlet of this station the water can be discharged or reused in the plant.

149647 24

The station 54 may comprise a cooling tower 106 in which the water is cooled in contact with the air. However, if the water is directly cooled in the tower 106, there is a risk that the air will be polluted by the most volatile pollutants remaining in the purification water.

This risk is small since the amount of pollutants emitted by the tower 106 in this way in the atmosphere is less than 5% of the amount emitted from the chimney 35 in a plant of the type shown in FIG. 1, 10 where the flue gases are not recirculated.

To avoid this risk, the water can be cooled in a heat exchanger 105 where the coolant is non-contaminated water which is circulated in the cooling tower by means of the pump 107.

15 A further feature of the embodiments of FIG. 3-5 is that you do not let the water out of the system in liquid form, thereby avoiding contaminating the environment with the pollutants contained in the water.

20 This means that the cooling and purification water must circulate in a closed circuit in the plant.

In the FIG. 3, 4 and 5 embodiments of the system, the cooling and purification water circuit is as follows: - The water from the cooling station 54 by means of the pump 55 is supplied to the cooling means 49 and / or 50 in the chamber 22 and to the means contained in the chamber. 17 serves to condense the steam and purify the fumes, gases and comprises either the nozzles 45, cf. 3 or the plates 46 with water film, cf. 4 or tub 30 48, cf. FIG. 5th

The purification water and condensation water containing pollutants, fibers and binder constituents flow out through the openings 24 and 25, are passed into the purification chamber 17, the separator 18 and a collector 26, 35 leading the water to the filter apparatus 51, where the water is purified from the solid particles 56. such as fibers and insoluble portions of the binder.

149647 25

This waste is collected on a conveyor belt 57.

The purified filtered water containing only undissolved pollutants and binder constituents runs down or is pumped to the treatment station 54.

5 It has been found that when the purified water circulates in a closed circuit, it is necessary to maintain the concentration of solutes or suspended substances in the filtered water below a certain value of the order of 3-4% in relation to the dry matter volume per minute. water mass-10 amount. Above this value, a portion of the dissolved or slurry substances dissolved in the purification water - in particular micro-fibers or microparticles of binder which are not trapped in the filter apparatus 51, and soluble binder components - are deposited in the various parts of the plant. The binder 15 polymerizes and eventually forms viscous or rigid layers, which preferably close nozzles 45, 49 and 50 and also close the openings in the receiving member 15 which serve for passage of the flue gases 29. The consequence is that the amount of flue gases containing is evacuated, reduced, 20 and the cooling of the flue gases is reduced, so that the system must be stopped in a short time.

In order to keep the concentration of substances in the water below the desired value, it is necessary to remove quite large quantities of substances from the purification water, a large part, approx. 20-30%, 25 of the binder sprayed from the member 13 on the fibers is found in the purification water, cf. the process described above. In the case of large installations, this means that per day, 3000-5000 kg of binder (dry matter) must be introduced into the closed water circuit, and in order to maintain the concentration of 30 equilibrium value, equivalent amounts of binder must be taken from the water.

For this purpose, the following methods can be used.

One method is to treat at least that part of the purification water in a centrifuge, which can remove from the water considerably smaller solid particles than possible by the filter 51. As can be seen from FIG. 3, the water treated in the centrifuge 58 can be returned to the vessel 52, but it can also more conveniently be returned to the cooling means 59.

Another method is to treat the water by adding a flocculant which is then separated.

These two methods have the disadvantage that only the insoluble substances contained in the water are taken from the water. The dissolved binder, which constitutes the largest proportion of the substances to be removed, is unaffected or almost unaffected.

FIG. 6 shows a schematic representation of a complete system for carrying out the method according to the invention.

The plant comprises: - a fiber-producing member 101, wherein the molten material 102 is introduced into a high-speed rotating body formed at the circumference by a plurality of holes through which material is pressed out under the influence of the centrifugal force. The rays thus obtained are then subjected to the influence of an annular, concentric stream of high velocity hot gas directed downwardly, drawing the material to thin fibers, - a fiber distributing means constituted by a pivoting nozzle 14 through which the stream 12 of 25 fibers and gas from the fiber-producing means passes, - a cooling means with nozzles 50 for atomizing cooling water in stream 12. This means is disposed between the distributor 14 and the means 13 for applying binder, 30 - a means 15 for providing - the receiving chamber 22, which is shaped like a parallel pipedum, and which is bounded below by the band 15 35 and along the sides of vertical walls 21 and in the upper part of a horizontal wall. 32, located at a distance of 200 mm below the fiber-producing member 101, 149647 27 and comprising a circular aperture 33 / through which the flow 12 passes. The edge of this opening is so profiled that the flow 12 easily penetrates and tangles the flow. Vertical walls 21 define above 5 the perforated band 15 the area in which the mat is provided - a chamber 16 located below the perforated band 15 in the area where the mat is provided and in which suppression is established by means of a fan. 19, - an expansion and purification chamber 17, located after the chamber 16 and comprising atomizing nozzles 45 arranged so as to form blankets of water droplets in the path of the flue gases 29.

15 - a cyclone-type water separator 18 arranged after the chamber 17.

- a fan 19 which forces all the gases passing through the receiver 15 to the pipeline 34.

20 - a recirculation pipe 34 whose outlet end through the opening 36 opens into the upper part of the chamber 22 in the region surrounding the fiber distributor 14. An amount of flue gas of approx. 90 - 95% of the amount passing through the receiving means 15 is recirculated to the chamber 22 through the conduit 34 and the opening 36.

- a pipeline 35, starting from the pipeline 34, discharges 5-10% of the flue gases passing through the receiving means 15 to an combustion apparatus 39. After passing through this combustion apparatus, in which the flue gases are brought to a temperature above 600 ° C, the flue gases are discharged to the atmosphere.

sound-absorbing panels 99 and sound-insulating panels 100 disposed on the walls 21 and 32, respectively, in the immediate vicinity of the fiber-producing member 101.

A drainage channel 103 which collects the purification water and the cooling water as well as the fibers, binder and binder ingredients softened or suspended in the water which originate from the openings 24 and 25 at the bottom of chamber 17 and cyclone 18, respectively.

- a pump 104 which conducts the water from the drainage channel to a filtration apparatus 51.

- a filtering apparatus 51 of the kind comprising a mesh net and arranged to perform a swinging motion, which separates the insoluble waste from the purifying water.

a vessel 52 which is located below the filter 51 and collects the filtered water.

a heat exchanger 105 wherein the water contained in the vessel 52 is circulated by the pump 53 and cooled, releasing the heat which it collects by contact with the flue gases 29 during passage through the chambers 22, 16 and 17.

- a cooling tower 106 in which the cooling water from the heat exchanger 105 is circulated by the pump 107.

- a pump 55 with which the water from the vessel 52 is recycled and returned to the means 50 for cooling the flow of fibers and gas, to the means 45 25 for condensing and purifying the flue gases 29, to the station 108 for preparing the binder and to the water treatment station 109 .

a water treatment station 109 in which the water to be treated is pressurized at a pressure of 30 1600 kPa by means of the pump 77, after which the water is passed through a heat exchanger 83, with which the water is heated to approx. 80 ° C. At the outlet of this heat exchanger, the water enters a mixer 78 in which it is contacted with steam, preferably superheated steam, bringing its temperature up to approx. 200 ° C, keeping the water at this temperature for approx. 2-4 min. in the reactor 82 located at the outlet of the mixer 78. At the outlet of the reactor 82, the water is subjected to cooling to a temperature of 40-50 ° C, after which an expansion member 86 drops the pressure to the atmospheric pressure and the water is then brought to 5 a centrifuge 110 which separates from the treated water the undissolved binder. The finished water is sent back to the vessel 52.

a conduit 111 for supplying fresh water to the vessel 52 for maintaining a constant volume of water in the abutment.

conveyors 57 and 112 for transporting * waste from the filter 51, from the water treatment station 109 and from the manufacturing lines to the waste treatment station 113.

15 - a station 113 for waste treatment. This station comprises an oven equipped with gas-fed or electrically-fed radiators, with which the waste is brought to a temperature of approx. 600-700 ° C in such a way that the binder and its constituents are incinerated while sintering the fibers into sheets of small dimensions, after which the sheets can be reinserted into the fiber manufacturing circuit.

FIG. 7 shows yet another embodiment of the system according to the invention. This plant comprises the following parts: 25 - a fiber-producing means in which the molten material, in particular glass, flows from a crucible 114 and forms threads 115 which solidify before being contacted with drive rollers 116 which place these solidified threads or rods in a fast stream 117 of 30 hot gas, the flow direction being usually perpendicular to the direction of the wire. The result is that the end of the wire is heated and softened so that the stream can draw fibers, thereby forming a stream 12 of fibers and gas which is transported against the member to which the mat is provided.

a cooling means comprising nozzles 50 which spray cooling water on stream 12.

A means 13 for applying binder to stream 12, which means relative to the flow direction of stream 12 is located in front of the cooling means.

5 - means 15 such as a perforated conveyor belt for providing the mat.

a receiving box 22 having the shape of a parallel piped and lowered by the perforated band 15, along the sides of the vertical 10 walls 21 and the top of the wall 32 and back of the vertical wall 118 which is positioned approx. 200 mm from the opening of the stream 117, this wall having a rectangular opening 33 for this stream.

The edge of this opening is profiled in such a way that stream 12 readily enters the chamber as the edge tangles the stream. The vertical walls 21 define the perforated band 15 in the area where the mat is provided.

- a vacuum chamber 16 disposed below the perforated band in the area where the mat is provided.

- a cleaning chamber 17 located below the chamber 16 formed with exit openings 47 which open below the surface of a quantity of water 48 and through which the flue gases flow out. The spray nozzles 45 serve for supply of purification water running down an overflow pipe 24 to a collector 26.

- a cyclone-type water separator 18 located behind the chamber 17.

30 - a fan 19 which forces the gases arriving with the fibers to the receiving means 15 through this receiving means and further to the pipeline 34.

a pipeline 34 for recirculating the gases, its outlet opening into the chamber 22 through two openings provided in the vertical walls 21 on both sides of the fiber-producing member in the immediate vicinity of this member. An amount of approx. 95% of the gas passing through the perforated blanket 15 is recirculated in the chamber 22 through these openings.

a conduit 43 which opens into the chamber 22 in an area at the outlet end of the chamber serves to transfer through the fan 44 through the fan 44 the non-recycled portion of the flue gases to the combustion means 39 through the conduit 35.

sound-absorbing panels 99 and sound-insulating panels 100 are mounted on walls 21, 32 and 118 in an area adjacent to the fiber-producing member.

a vessel 103 receives the cleaning and cooling water and the entrained fibers and the dissolved or suspended binder or binder components from the openings 24 and 25 at the bottom of chamber 17 and cyclone 18, respectively.

- a pump 104 brings the water from this vessel to a filter apparatus 51.

a filter apparatus 51 of the kind comprising a mesh and arranged to perform oscillatory movements serves to remove the insoluble waste from the purification water.

a vessel 52 disposed below the filter 51 collects the filtered water.

25 - a heat exchanger 195, in which the water from the vessel 52 is circulated by means of the pump 53 and cooled during release of the heat it collects with the flue gases 29 during passage through the chambers 22 and 17.

The system just described further comprises, as shown, a water treatment station and a waste treatment station, which stations are analogous to those with reference to FIG. 6 stations described.

Pig. 8 shows yet another embodiment of a plant 35 according to the invention. The plant comprises the following parts: - a fiber-producing member receives the molten material from the front portion 118 of a furnace, the material being fed through the openings in a draw tray 119 in such a way as to obtain a large number of material strands flowing through a draw range and passes between converging gas streams having high velocity. The outlet openings 120 for these gas streams are located close to the glass wires and the gas streams are directed downwardly substantially parallel to the direction of movement of the glass wires. For example, the streams are made up of steam under high pressure.

The fibers obtained, the drawing currents and the surrounding fluid being induced, form the current 12.

- a cooling means 50 which sprays cooling water on stream 12.

- means 13 for applying binder when spraying in stream 12, - means 14 for distributing the fibers, which means are formed by two nozzles which supply air under pressure 20 for controlling the fibers in the desired direction.

Moreover, in FIG. 8 illustrated in the same way as in FIG. 6.

FIG. 9 shows yet another embodiment of the system according to the invention. The plant includes the following parts.

25 - a fiber producing means in which the molten material in the form of a wire 121 and by means of currents flowing at high velocities from openings 123 is directed to the periphery of a rotor 122 which rotates at high speed. The rotating body 122 30, under the influence of the centrifugal force, comprises a portion of the material for fibers and transfers the second portion to another body 124 which similarly converts the material into fibers. Usually there are two or three bodies, such as the body 122.

35 Through a perforated wreath 125 enclosing the rotors 122 and 124, streams of fluid which affect the obtained fibers at high velocity are emitted.

Claims (7)

149647 targets the fibers to the receiving means. These flows are made up of air or steam under high pressure. Usually, the openings 125 are also used for spraying the binder onto the fibers. A method of treating flue gases in connection with the manufacture of articles, such as lintels, floral webs or mats of mineral fibers, in particular glass fibers, wherein the fibers emanating from a gas-drawing plant are applied to a binder, containing contaminants, and then conveyed to a receiving means by which the fibers are separated from the total flue gas stream, including the draw gas stream, the air or gas streams induced by it, and the contaminants entrained, and wherein said total flue gas stream after passage through the fiber blank and the receiving means is purified with water so that the flue gas stream is cooled vigorously at the same time, characterized in that most of the water purified flue gases are recycled to form the draw gas stream or for use as a complement to the draw gas quantity used during its flow to the receiving member and the water-purified flue gases similar to those of anl the gas introduced into the egg is purified of pollutants and passed to the atmosphere. 149647 Process according to claim 1, characterized in that the flue gas flow to the atmosphere is substantially equal to the draw gas flow. 3. A method according to claim 1 or 2, characterized in that the flue gases recirculated in the fiber production zone are directed so that they follow between the fiber production zone and the fiber receiving zone a path substantially parallel to the path of the draw gas stream. Process according to claim 1, characterized in that the purification water, after cooling and preferably after partial purification, is reused as new purification water and / or for atomizing the fibers to cool them. Process according to claim 1 or 2, characterized in that the flue gas to be discharged to the atmosphere is purified by thermal treatment, preferably by direct combustion or catalytic combustion. The fibers, the control currents and the induced fluid form the stream 12. A cooling means 50, which sprays cooling water on the stream 12, is disposed after the openings 125 and a portion of these openings serves to atomize the binder. Moreover, in FIG. 9, analogous to that shown in FIG. 7th A method according to claim 1 or 2, characterized in that the flue gas to be discharged to the atmosphere is subjected to electrostatic cleaning. An apparatus for carrying out the method according to claim 1 and of the kind comprising a means (11) for producing fibers, a chamber (22) surrounding the flow of fibers between the fiber making means (11), and a fiber receiving means (15). ), on which the fibers are deposited to form a fiber blank (23) and having an inlet opening (28) associated with the chamber (22) for a draw gas stream containing the fibers with applied binder and contaminants, and for those of the the draw gas stream induced air or gas streams, and means for purifying and simultaneously cooling the flue gases (19) with water after their passage through the fiber blank (23) and the fiber receiving means (15), characterized in that said flue gas cleaning means