NO743568L - - Google Patents

Description

Procedure for the elimination of pollution factors in the manufacture of mineral fiber products.

The present invention relates to methods and devices for the elimination or reduction of pollution factors which are harmful due to toxicity, odor or opacity and which are found in gaseous or liquid effluents in facilities for the production of mineral fiber products, in particular mats and plates,

as well as reduction of noise from these facilities.

Invention n thus relates to factory facilities for the production of mineral fiber products, in particular glass fiber mats etc.

where the fibers are joined using thermosetting or thermoplastic adhesives, which give the final product rigid joints

between the fibers.

The binders that are usually used for such production are phenol resins or amino plastics, in pure form or modified form, because these have advantageous properties for the production of products from agglomerated fibres. The binders are thermosetting, soluble or emulsifiable in water, seal well to the fibers and are relatively cheap.

In general, the binders are dissolved or dispersed in water to which certain ingredients are added which form an adhesive mixture that is sprayed onto the fibres.

Under the influence of heat during the manufacturing process, the adhesives release volatile toxic components with a pungent odor - which is noticeable even at very low concentrations - of the type phenol, formaldehyde, urea, ammonia and decomposition products of other organic substances.

•Other binders are used for certain purposes on grounds

of their low price. Certain extracts of natural products herd3s

by crosslinking, such as linseed oil or oxidation. Others are thermoplastic such as e.g. asphalt. All of the aforementioned binders are heated for at least some time to a sufficiently high temperature to release volatile components that are harmful or irritating, e.g. because of their smell.

In the following, the term "binder" means any or any mixture of the above-mentioned binders, whether they are used in liquid form, suspended in water or in another liquid or as an emulsion.

The invention relates to that part of the plant for the production of fiber products which can be called the receiver post and which is located immediately after the body that produces the fibers, and where the following operations mainly take place: Lowering of mineral fibers from the production body, during the formation of a mat or plate,

gluing the fibers with a binder, which usually contains or emits polluting components,

forming a mat or similar on the receiving body which usually consists of perforated cloth,

cooling of the fibers and the blow-out media, usually by means of air,

separation of the fibers and the conveying gases by the gases being filtered through the fiber product that is formed,

Removal of all components that are not retained

of the fiber product, from the plant.

In the aforementioned receiver post, large quantities of gaseous and aqueous media come into contact with the binder containing polluting factors and which are further contaminated during the process, which contains features common to all known production of mats or sheets of fibers which are joined with a binder and which shall be described in the following. a) Contamination of the flowing gas quantities takes place in the following way:

The binder is sprayed into a mixed stream of fibers

and gases and possibly liquids that come from the fiber production plant, in the form of a mist of fine droplets. Part of the binder is captured by the fibres, another part is deposited on the walls of the apparatus and the last part is found in the exhaust gases as microdroplets and steam.

There are thus two contamination routes for these media, namely on the one hand binder liquid and on the other hand binder vapor. The nebulizer for the binder used sprays out the particles within a fairly large diameter. The finest droplets are not captured by the fibres, but pass through the mat (fibre product) while this is being formed and will be suspended in the gases and liquids that pass through the mat.

The drops of binder that are deposited on the fibers during the gluing process are exposed to the kinetic effects of the gas and liquid streams that pass through the mat during its formation. A large part of the droplets will therefore be torn loose from the fibers and travel through the mat and be suspended in the evacuated media (liquids and gases).

The requirement to achieve an even distribution of the binding agent in the mat leads to the binding agent being atomized into the flow of fibers and gases in an area that lies close to the fiber production outlet, where said flow still has a relatively defined geometric shape, but where the temperature is often so high that a large part of the binder or at least the most volatile components evaporates. These polluting vapors mix with liquids and gases and contaminate them.

In the following text, the term "flue gases1' or "exhaust gases<11> will be understood as the waste gases that pass through the fiber product and are evacuated after the fiber uptake, that is to say both the discharge or transport gases from the fiber production facility, any cooling and correction gases or liquids that are added or entrained and polluting components in the form of microdroplets or vapors suspended in these liquids or gases, b) The function that the water fulfills during the adhesive absorption process will inevitably cause significant pollution.

The water is used for: diluting and transporting the binder when it is used in liquid form, washing the exhaust gases, which includes the following operations: capturing as large a proportion of the pollutants found in the exhaust gases in the form of microdroplets or vapors as possible so that the pollutants in the flue gases are transferred to wash - the water,

to capture and entrain between the walls of the absorption organ (recipient organ) fibers suspended in the flue gases,

wash the various parts of the receiver plant (the perforated cloth), smoke ducts, to remove binding agent and de-clayed fibres.

During these processes, the cleaning or washing water will absorb soluble, insoluble or vapor-form binder components and the concentration of polluting components can become high.

The description of the gas/water pollution conditions is based on observations made in relevant manufacturing facilities.

The description is given in such a way that information and other explanations can appear without this changing the invention.

In all production facilities for the production of agglomerated fibres, regardless of which fiber production processes are used, the pollution of the waste media described below will concern large amounts of waste water.

In facilities equipped with fiber production devices where the fiber material is converted into fibers using gas jets with high kinetic energy, the amount of flue gases leaving the atmosphere, for the most known methods, is of the following order of magnitude: 100 Nm 3 per kilos of fibers for the method described in US patent no. 2,133,236,

300 Nm<3>per kilos of fiber for the "AEROCOR" process (US patent no. 2,489,243),

70 Nm<3> per kilo of fibers for the process "SUPERTEL" (French pstent

no. I.I24.489),

which for large factories produces exhaust gas quantities of 500*000 to 1,000,000 Nm3/h ime.

In plants equipped with transport means for the fibers where the fiber material is converted into fibers by means of mechanical forces, centrifugation for example, and where the gas flow is only used to transport the produced fibers towards the receiver in a horizontal direction, the amount of exhaust gas is somewhat smaller, but still high, e.g. YES. Nm^ per kilos of fibers for the method described in US patent no. 2,577*431>which for a larger factory plant will produce exhaust gas quantities of §00,000 to 400,000 Nm3/hour.

The amount of contaminated water is essentially the same for all methods, approx. 1000 m^/tifce and more for larger industrial plants.

The large amounts of pollutants have led to the legislation in the individual countries first setting a limitation with regard to the concentration of phenolic compounds that go into the atmosphere and in some countries leading to a complete ban on the emission of pollutants.

In addition, several countries have mandates regarding restrictions on odors

or opacity for the drain.

In addition, the relevant factories will emit significant amounts of water vapour, on the order of 20 to 30 tonnes per year. hour for'larger facility, which makes the atmosphere unclear.

The noise from the factories is another pollution factor. In the facilities in question, noise is emitted mainly from two sound • sources, namely the fiber production unit and the fan that extracts the flue gases.

All production devices that are arranged either for transferring the fiber material to fibers or for advancing and transporting the fibers use gas streams at high speed. It is now known that the sound level emitted from such gas jets increases considerably with speed. The sound level can exceed 100 decibels in the vicinity of the fiber production apparatus and in the area where the workers are located. The mentioned level is much higher than what can be tolerated according to given laws and regulations.

The sound coming from the smoke extraction fan is transmitted through the connection channels to the pipe. The pipe will act as a sound antenna and emit sound waves into the surrounding environment. The embarrassment this causes in the neighborhood has caused the authorities in various countries to order the shutdown of certain facilities. The need for an elimination or reduction of the pollution factors, associated with sufficiently low costs so that the product price does not rise too much, has become urgent, a lot of work has been done in these areas and certain solutions have been proposed.

The method according to the invention is characterized by the fact that the flue gases are partially recycled (together with exhaust or transport gases that throw the fibers out of the fiber production plant, as well as contaminated waste and pollutants), so that the gases are made to pass the fiber product several times while it is being formed, that most of the heat from the fiber production plant is heat exchanged to water, which is cooled, that the flue gases are washed with water afterwards

they have passed through the fiber product and the receiving organ, whereby part of the pollution component in the flue gases passes into the water and cleans the part of the flue gases that is not recycled, before draining to the pipe, and that at least a part of the washing water is recycled, of which a certain fraction has undergone treatments for the separation of a significant part of the pollutants, and finally that the solid waste undergoes cleaning processes.

According to a particularly important feature of the invention, the amount of flue gases that are fed into the atmosphere is essentially the same as the amount of gas that leaves the fiber production plant.

The invention is based on recirculation of the majority of the flue gases in the plant and only the treatment and evacuation of a smaller part, as the recycled proportion can amount to at least Jjfo of the total amount of flue gas that is usually supplied to the atmosphere. The quantity of flue gases that must thus be cleaned before being emitted into the atmosphere will then be less than 5$ of the flue gases, which makes it possible to use an expensive but completely effective cleaning system such as e.g. combustion, without excessive energy expenditure.

Another feature of the invention is that the thermosetting resins are made insoluble in the water. This insolubilization takes place according to the invention by a heat treatment at preferably above 100°C, preferably at between 150 and 240°G. This heat treatment can advantageously take place under pressure. The use of this insoluble rendering process on at least part of the cooling water and the washing water is advantageously used to make the binder components dissolved in the water insoluble, so that they can then be separated in a known manner, whereby the concentration of contaminants in the washing water and cooling water can be kept at a reasonable level and the water reused in the installation. The washing water therefore circulates in a closed circuit and all the export of pollutants is eliminated.

One. another feature of the invention consists in a heat treatment to which the washing water is subjected, namely evaporation and heating of the steam to a sufficiently high temperature for the polluting components to be converted into non-polluting substances.

The invention also includes soundproofing devices that are adapted to the relevant shapes of pipes and flues,

for reducing the noise that the fiber-producing facilities emit,

and a special arrangement for discharging the exhaust gases that are not recycled into the atmosphere, which precautions reduce the noise to the surroundings.

Other features and advantages of the invention, especially the various advantages achieved by recirculation of the flue gases will be explained more fully in the following: Fig. 1 shows a receiver system of the type to which the invention is particularly connected. Fig. § shows part of the installation in fig. 1, but where the walls which limit the receiver chamber are extended all the way up to the fiber production member. Fig. 3 shows a receiver system which is made according to the invention. Fig. 4 shows another embodiment of a receiver system

according to the invention.

Fig. 5 shows another embodiment of the washing chamber.

Fig. 6 shows the degree of insolubilization as a function of treatment temperature and time. Fig. 7 shows a device for carrying out the heat treatment of the water under pressure, according to the invention. Fig. 8 shows a system for continuous operation, for treating the water.. - Fig. 9 shows an incineration plant for solid waste according to the invention. Fig. 10 shows another system for treating the solid waste. Fig. 11 shows a complete receiver plant for the production of fiberglass plates according to the invention. Fig. 12 shows an embodiment adapted to another method for producing gas fibres. Fig. 13 shows another embodiment of the invention adapted to a plant for the production of mineral fibers by blowing. Fig. 14 still shows an embodiment of the invention adapted to a plant for the production of mineral fibres, particularly from slag material. Fig. 1 shows a receiver (recording) system of. known type, on which the invention can be used. This facility includes: A fiber-producing body shown at 11, of a known type and usually used in factories for the production of mineral fiber sheets and where the material to be formed into fibers is exposed to a centrifugal effect or aerodynamic force or a combination of these. The aerodynamic force is applied to the material to be formed into fibers or on formed fibers, such as air or gas currents which usually have a high temperature and high speed. The produced fibers leave the apparatus 11, dispersed in a flow 12 of generally gaseous media in the form of high-energy currents surrounded by entrained currents from the surroundings which direct the fibers, as a rather limited bundle, towards the recipient organ.

A glue zone which is arranged in the flow path for the fibers and gases, between the fiber production apparatus 11 and the receiving body and where the atomizing nozzles 13 atomize the binder as a mist of small droplets in the flow of fibers and gas. A significant part of the droplets is captured and taken up by the fibres, the rest continues as a suspension in the fiber gases as microdroplets or gases.

A distribution member for fibres, 14, arranged in the flow path for fibers and gas 12, either between the production member 11 and the lime zone or between the lime zone and the receiving member, as gig. 1 shows, and which gives the fibers and accompanying gas an oscillating movement so that the fibers are distributed as desired on the receiving body in the form of a mat with an approximately uniform basis weight.

A receiving body which is reproduced at § 1, consisting of an endless perforated band or cloth which receives the fibres.

A box 16 arranged below the perforated band and i

the area where the fibers are deposited, the forming zone, and where a negative pressure provided by the fan 19 causes the entire amount of gas that follows the fibers between the production plant 11 and the perforated belt 15

passes through the mat being formed, so that no gaseous medium that has followed the fibers goes outside the forming zone.

Vertical walls 21 which extend from the perforated band 15 and approximately up to the production facility 11, and which limit the forming zone of the mat in such a way that a chamber 22 is formed

which surrounds the flow of fibers and gas, with an opening downwards, the walls of which are often called a hood or receiving chamber.

A fan 19 which provides a sufficient negative pressure

in the box 16 so that the entire amount of gas that follows the fibers passes through the mat that is formed, and which sucks the flue gases out to the atmosphere through the pipe 5*

It has already been mentioned that the amount of flue gases escaping to the pipe in a plant of this type is usually large.

In plants for the production of fibres, which are part of the described system, the transport or production jets of gas which are part of the plant have a very high speed. This speed, which is usually over 100 m per second, is much higher than that which is appropriate for laying down a desired mat, as this speed at the recording level should not exceed 10-20 m per second. It is therefore necessary to significantly slow down the flow of fibers and gas from the production plant. This braking is achieved by transferring a substantial part of the kinetic energy of the production jets to the medium into which they flow, as this medium is swept along and accelerated in the direction of flow and mixes with the production gases. This mixture of production gases and entrained or admixed gases which make up the gas flow around the fibres.

This forced movement of surrounding gases is a well-known phenomenon that occurs when a gas stream emerges in open air or in a room containing a gaseous or, for that matter, liquid medium. Flow mechanics shows that such a gas flow entrains significant amounts of surrounding gases, and that these entrained gas quantities increase with increasing primary gas flow and the primary gas flow's passage length through surrounding gases.

But this entrainment phenomenon is expressed gradually as the velocity drop for the primary flow is not great until after the primary flow has traveled a certain distance through the surrounding atmosphere.

In a plant of the type described above, the distance that the primary gas flow must cover in order for the gas flow and the entrained gas quantities to have the desired speed at the height of the receiving device (a speed of 10-20 m per second or less) will generally be over 2 to 3 metres, and the quantities of gas with which the primary gas jet from the production body 11 rips over this length, and which then passes through the receiving body 15, is at least 10 or 20 times greater than the primary gas flow from the fiber production facility 11.

In addition to the braking that the gas flows have to undergo together with the fibres, it is necessary for the fiber mat to be laid down correctly, that the direction of flow for fibres/gases is parallel and oriented in a direction from the fiber production body towards the receiving body.

To improve understanding, consider some imaginary sections made through the fiber/gas flow 12, delimited by parts that are perpendicular to the direction of flow, namely M, N,

0, P...

What has been said above will then mean that the flow through each section delimited by the parts M and N, e.g. the flow must maintain its direction and undergo a significant drop in speed.

These two factors, direction and velocity drop, will within each "piece" have the desired values if the primary flow drags with it uniformly along the circumference of the piece the necessary amount of gas which will be proportional to the product of the amount of gas entering through the cross-section M, and the relative velocity drop that the gas flow undergoes through the considered piece MN.

This relative velocity drop is equal to the difference between the velocity of the gas flow at the inlet through the cross-section M and the velocity of the gas flow at the exit through the cross-section N, in relation to the former velocity.

If the surrounding gases for each passage through such cross-sections, from the fiber production plant and to the receiving body, can deliver the necessary gas quantity so that the direction and braking of the gas flow achieve the desired values, one obtains an external or secondary gas flow along the primary flow of fibres/gas and in the latter's production direction towards the recording organ. These secondary flows are shown in fig. 1 at the arrows 27-

In receiving facilities of the type shown in fig. 1

all gases that are entrained by the flow 12 will be made up of atmospheric air that enters the chamber 22 through the opening 28 which has large dimensions and is taken out at the top of the chamber 22 in an area located near and around the fiber production member 11. Fig. 2 shows an embodiment of the gas flow in the recording chamber, where the surrounding air cannot have an impact on the primary flows from the fiber production body. Fig. shows a part of a receiver plant, including the production organ for fibres. 11,.. from which flows a mixture of fibers and gas 12, a gluing device 13, a distribution device 14

for fibres, a receiving member 15 and a suction box 16 which sucks out the flue gases 29 after they have passed the mat 23 which is formed. All these elements are as in fig. 1. But in fig. 2, the walls 21 which delimit the receiving chamber 22 are extended all the way up to and around the fiber production member 11 so that the opening 28 which puts the chamber 22 in contact with the outside atmosphere is significantly reduced and consequently the possibility of supply from it is significantly reduced.

If one therefore looks at a cross-section through the flow 12, e.g. M and N, which are located near the fiber production facility 11, i.e. near the blowing nozzles for the fiber output, where fibers/gas have the highest velocity, the surrounding environment will not be able to supply the flow 12 of fibers and gas throughout amount of gas that will be able to be carried all the way down to its 0 and P

where the current 12 has a lower speed.

The gas streams 30 that come from the lower parts of the plant will rise along the walls 21 and towards the zones that have a higher speed, be swept along by the stream and be accelerated again generally in the direction of flow. Vortex formations JL will thus occur between the flow 12 and the walls 21 in the chamber. The intensity of these vortices will increase to the extent that the surroundings can no longer supply secondary gas and the direction of circulation for the vortices is such that fibers will be dragged along the walls 21 of the chamber and towards the distributor 14, the gluing means 13 or the fiber production facility 11.

If one therefore reduces the atmosphere-air quantity

which can enter the stream chamber in the described facility in fig. 1 and 2, to an amount that is much smaller than the amount of air that the primary jet can entrain, the vortex formations 31 could become so large that the fibers are swirled up so that they will adhere to and clog the distributor and the gluing nozzles and disrupt the operation . The vortices also have the effect of destroying the shape

on the mat being formed, 23, as shown in fig. 2.

Investigations of industrial facilities of this type show that this upheaval of fibers can be reduced to an acceptable degree when the amount of air that is entrained into the chamber is not less than 60 to 70% of the required amount. Below this limit iri.1 industrial operation be difficult or impossible.

If one wants to further reduce or completely exclude atmospheric air from entering the chamber, the turbulence will be so strong that the fibers will not settle on the receiving body.

One of the purposes of the invention is to provide a method which will substantially reduce or completely exclude the amount of atmospheric air that enters the receiving chamber while maintaining the desired operating conditions for depositing the fibers on the substrate.

This method consists in using as secondary gas not atmospheric air, but part of the flue gases that have been sucked out with the help of the fan, i.e. recycling a part of the flue gases that continuously pass through the chamber back to the receiver chamber.

A device which enables this method is shown in fig. 3*The receiver chamber 22 is closed in the upper part with a cover 32 which is provided with an opening through which the stream 12 of fibers and gas from the fiber production apparatus 11 enters the chamber 22. The edges 33 around this opening are deflected tangentially to the stream 12 and have been profiled so that they facilitate the inflow of the fibre/gas stream.

For the sake of simplicity, the cover 32 can be placed at a distance H from the fiber former 11.

The apparatus in fig. 3 consists of a washing chamber 17 placed after the suction box 16 and with a generally larger cross-section than. this and provided with devices in which the flue gases 29"i.e. the secondary gas which follows the fibers between the fiber former 11 and the receiving member 15 as well as suspended contaminants are brought into contact with a washing medium, especially water. In the washer 17, the smoke is partially freed of the suspended elements which essentially consist of fibers and binder with which the gas is filled when passing through the gluing zone and the fiber mat which is being formed. Upon contact with the wash water, the fibers contained in the flue gases will collect water droplets and therefore tend to settle due to gravity, towards the bottom of the chamber 12, and this phenomenon is accelerated by the sudden drop in velocity of the flue gases as a result of the expansion of the flow cross-section at the transition from the box 16 to the chamber 17. Part of the polluting droplets or vapors are captured by the washing water droplets and dissolve in them. These two operations then form the washing of the flue gases. The wash water, which contains at least part of the pollutants from the flue gases, exits through the opening 24.

The apparatus also comprises a separation system 18, of the cyclone type or electrostatic, arranged between the washing chamber 17 and the fan 19, in which the flue gases are at least partially freed of water droplets from the washing step, which it is important to remove before entering the fan 19. Washing water with flue gas contaminants in liquid form is drained from the separation system through the opening 25.

A collector 26 leads the drained washing water from the openings 24 and 25 to a treatment zone.

The fiber/gas stream passes the glue member 13 and the distributor member 14. The fibers are deposited on the receiver member 15 and the smoke gases 29 pass the fiber mat during formation, 23, the suction box 16, the wake chamber 17, the separation device 18 and are blown by the fan 19

into the duct 34*A part of the flue gases is evacuated from the system, through the opening 35*The other part is led through the duct 34

to the receiver chamber 22 where the gas passes through an opening 36

which is located near the fiber former 11.

The amount of gas that enters the receiver chamber through the opening 33 is equal to the sum of the gas from the fiber former 11 and the introduced secondary air amount 27 which is drawn in from the surrounding air, depending on the height H. The secondary gas amount. into the chamber thus increases with increasing height H.

In order for the system to be in equilibrium, the quantity of flue gases that are drawn out of the system through the opening 35 is as large as the quantity of gas that enters the system through the opening 33• The quantity of flue gases that goes to the atmosphere will thus decrease with decreasing distance H.

Fig. 4 shows a particular embodiment according to the invention where the distance H = 0, i.e. that the fiber former 11 or at least the nozzle openings for the blowing gas in the fiber former are placed all the way down

in the chamber 22. The amount of flue gases to be fed to the atmosphere will then be approximately the same as the amount of gas introduced from the fiber former 11.

The quantity ratio for the recycled gases can thus in this embodiment rise to at least 96 to 97$*

On the facilities shown in fig. 3°g 4>according to the invention, the recycled amounts correspond to the amount supplied from the blowing means in the fiber former 11, as the gas flow in the chamber 22 goes entirely in the direction of the blowing gas flow, without disturbing vortex formation. The recycled gases follow

essentially the flow lines 37*

One of the advantages of the invention is due to the fact that, thanks to the fan 19, the gas streams 37 of recycled flue gases can be given a speed that is somewhat higher than that of the streams 27 of atmospheric air with which the stream 12 of fibers/gases surrounds itself in the apparatus in fig. . 1. The gas streams 37 thus have sufficient energy to oppose a ejection or untwisting of fibers from the direction of flow.

One of the most significant advantages of the invention lies in the fact that the quantity of flue gases to be discharged from the system does not need to be greater than 3~4$ of the quantities of flue gases that are usually fed to the pipe, of an order of magnitude as previously mentioned, so that it becomes possible to treat the small amounts of flue gas in an expensive but completely effective way.

According to the invention, it is proposed to treat the flue gases that go to the pipe, through the opening 35"Ye& combustion, which consists in bringing the flue gases up to a temperature above 600°G, so that the flue gas's polluting constituents, especially the phenolic compounds, are converted into non-polluting constituents such as CO ^

and HgO. This treatment also has the advantage that annoying odors are broken down. The combustion is carried out in the plant 38 of a known type, comprising a combustion chamber 39j a burner /\ 0 which is supplied with fuel, and a known flame stabilizing device 4-1* The combustion temperature can be kept down to 300-4-00°C in the presence of combustion catalyst.

The purified flue gases are led to the atmosphere through pipe 42. At the outlet of pipe 42, the flue gases still have a sufficiently high temperature and constitute such a small amount of gas that condensation of water vapor in the flue gases does not occur until the gases are completely diluted in the atmosphere. No fog formations thus occur at the outlet from pipe 42.

Another advantage of the invention is that when the flue gases are recycled or treated and completely cleaned, it is not necessary to carry out a very complete washing beforehand, which means that the dimensions and costs of building the washing plant 17 and the separation plant 18 can be reduced, which are arranged in front of the fan 19.

The installations shown in fig. 3°S 4 includes

according to the invention, a receiving chamber 22 which surrounds the gluing station and the distribution member for fibres, which makes the latter two difficult to access. However, inspection windows can be arranged in the chamber wall near the fiber former 11.

If you want to prevent recycled flue gases, i.e. not completely purified flue gases, escaping from the chamber 22, the pressure in the chamber must be equal to atmospheric pressure or a few millimeters of water column lower (1 to 2 mm H20).

However, this makes it possible to avoid any leakage of smoke in the event of any sealing failures, when the windows are closed. The pressure in the chamber 22 is regulated to the desired level by adjusting the underpressure in the suction box 16 from the fan 19, on the design shown in fig. 3*

Another method consists in leading the flue gases that are to go to the pipe out, not through the recirculation channel 34>, but directly to the chamber 22 through an opening 43 that is taken out in the chamber wall in the area where a pressure is maintained at the desired level, as fig . 4 shows. The flue gases leave the chamber 22 with the help of a small auxiliary fan 44°g and leave the plant through the channel 35*Fan 19 then only ensures recirculation of the flue gases. This design enables a more accurate localization of the negative pressure zone.

One of the characteristic features of the invention is that it is possible to regulate the supply of atomized binding agent through the spray guns 13 as a function of the amount of suspended binding agents found in the recycled flue gases and which settles on the fiber mat when the flue gases pass through it.

The recirculation achieves that the flue gases repeatedly pass through the fiber mat which is being formed and even though the capture capacity of the mat is small due to the low speed that the flue gases have through the mat, the number of through-flows (approx. 15 per minute ) so high that the amount of suspended binders from the flue gases deposited on the mat is not significant. This makes it possible to reduce the amount of binder that is atomized from the gluing member 13 while increasing the binder yield by approx. 5%, which again leads to a not inconsiderable contribution.

In a plant as shown in fig. 1 must be maintained

a certain temperature in the receiver chamber 22 and thus remove the heat that is introduced with the fiber material and the blowing gases. The binder is thermosetting and will thus, under the influence of heat, undergo a continuous hardening process which gradually transfers the binder from liquid form, in which it is atomised, to solid form. If the temperature ±1: the chamber 22 is too high, the binder will be able to pre-polymerize to the extent that it more or less loses its binding ability to the fibers. The phenomenon is also due to premature hardening, which is avoided by cooling down the receiver chamber 22.

In the plant shown in fig. 1, this cooling takes place with the help of entrained secondary air from the atmosphere around the plant, which usually has a lower temperature than the desired maximum temperature in the chamber 22. The amount of heat supplied to the chamber through the fiber material and the blowing gases from the fiber former is, depending on the fiber forming methods, between I500

and I5.GOO Kcal per kilo of fiber material, and this amount of heat is transferred by mixing with secondary air to this and to the flue gases as a whole, which in turn emit a small part of the heat to the washing water when the gases come into contact with it, the rest goes to the atmosphere.

In a plant, which is shown in fig. 3°g 4, the small relative amount of flue gas that is fed to the atmosphere will only draw out a correspondingly small amount of heat and one must therefore use another method for cooling the receiver chamber 22.

The invention proposes such a method. It consists in transferring at least part of the heat supplied to the chamber 22 through the fiber material and the blowing gases to a heat transfer medium, especially water, by bringing the fiber/gas stream or the flue gases into contact with this medium. After the medium has absorbed the desired amount of heat in the chamber 22, this medium is led out to a place outside the chamber and the medium is cooled again in any suitable way outside the chamber.

The heat exchange between the fiber/gas stream or the flue gases, and the cooling water, can take place either by direct contact between these media or through a heat-conducting wall that separates them.

It is known that the amount of heat exchanged per unit of time in these methods is proportional to the temperature difference between the heat exchanging media and to the contact surface.

The relatively high ones. speeds of the gas or flue gases mean that the available time for the heat exchange is short. In order to achieve sufficient cooling, the exchanged heat per unit of time be large. According to the invention, methods and apparatus are proposed for carrying this out.

One of the methods consists in transporting the appropriate amount of heat out of the chamber 22 by cooling the flue gases in the suction box 16 and the washing plant 17 where the available spaces make it possible to use large contact surfaces between flue gases and cooling water. These large contact surfaces can be created in several ways: either by finely distributing the water as droplets or by letting the water flow as a very thin film in the flue gases or by bubbling the flue gases through the water.

In the device shown in fig. 3 showers e.g. cooling water from the atomizing nozzles 45 out in the form of shower jets or a mist with a direction approximately perpendicular to the flow direction of the flue gases 29. The flue gases which have just flowed through the formed fiber mat enter the suction box 16 at a temperature of 80 to 100°C and are cooled by contact with these liquid streams, with a temperature of 30 C. The temperature of the water at the inlet to the nozzles 45 is approximately 15 to 20°C, depending on the cooling methods. On contact with the flue gases, the water is heated to a temperature of 30

to 40 C, depending on the amount sprayed.

The recycled part of the cooled flue gases goes after passing the separation system 18 and 19 to the receiving chamber 22 where the gases are mixed with gas from the fiber former 11

and cools the fibers and the fiber production gas (blowing gas) in a similar way to the atmospheric air in the plant shown in fig. 1.

Another design example is shown in fig. 4, where the water flows along the walls 46 as a very thin film and where the flue gases 29 rise along and between the mist see walls in heat exchange with the water film and are thereby cooled.

Yet another embodiment is shown in fig. 5*With this arrangement, the flue gases 29 flow through the opening 47 which protrudes below the surface over a certain quantity of water which is found in the tub 48 arranged in front of the suction box 16 and creates in this water a strong bubbling effect where the walls of the gas bladders offer a large surface to the water.

Another method consists in extracting the added calories from the fiber/gas mixture by directly cooling the fiber/gas stream 12 while showering water on this stream. The spraying of water into the gas/fibre stream thus takes place in a zone where the contact surface cannot be very large because the space is restricted, but where the temperature difference between the heat exchange media is large.

Other designs are conceivable. For example, the atomizing nozzles 49 in the example shown in fig. 3 is placed between the fiber former 11 and the gluing plant 13 and a fine mist of water is sprayed in the direction of the gas/fibre flow.

The drops will then, when supported by the gas/fibre flow, which in this zone has a high temperature, up to 600°G, evaporate instantly.

The large amount of heat of around 650 to "J00 Kcal per kilogram of evaporated water that is used to evaporate the micro-droplets is taken from the fiber-gas flow which then undergoes a rapid cooling as the temperature at the height of the gluing plant 13 has dropped to 100 to 120° C. The steam produced is taken out together with the flue gases and passes through the fiber mat 23, the suction box 16 and the washing chamber 17, where the steam in contact with the heat exchange water coming through the nozzles 45 is condensed and transfers condensation heat to the cooling water coming through the nozzles 45*

The arrangement of the cooling water nozzles 49 in the direction towards the gas/fiber flow 12 built between the fiber former 11 and the drying plant 13 constitutes a preferred embodiment according to the invention. The device has several advantages: Firstly, the temperature difference between the two heat exchange media, i.e. the fibre-gas flow and the water, is greatest in this area and the heat transfer is thus greatest.

Next, it is achieved that the atomization of binder takes place in a cooled fiber/gas flow (100-120°C), whereby the breakdown of binder and loss of volatile components is limited or equal to zero.

One thus achieves an increased yield that binder on

about. 5$°S resulting in reduced flue gas pollution.

Another embodiment is shown in fig. 4, where the spraying device for cooling water 50" in countercurrent to the fiber/gas flow 12, is arranged between the gluing plant 13 and the receiving device 15. As in the embodiment in fig. 3 Sar cooling water in vapor form through the fiber mat that is formed, 23. The water is condensed by transferring the latent heat to flowing water films that flow down along the walls 46 in the washing chamber 17*

The water leaves the plant through the openings 24 and 25 which are located in the lower part of the suction box 16 and 17 and from the separation device 18, to the chamber 51 where the water is freed of solid suspended substances, especially fibres.

The vessel 51 can either be provided with a mesh filter which can be a known vibrating or rotating filter, or a decanting system or a centrifuge, likewise of a known type.

The water freed of solid suspended particles is collected in the container 52 and then transported by gravity or a pump 53 to a cooling station 54. From the cooling plant, the cooled water can be led out of the plant or recycled in the system.

The cooling system 54 can consist of a cooling tower 106 of a known type, where the water is cooled in contact with air. But if the wash water is cooled directly in the tower 106, there is a risk of air pollution with the most volatile contaminants in the wash water. However, the risk is small since the amount of contaminants that can go to the atmosphere through tower 106 is less than 5% of the amount that is fed to pipe 35 in a non-recirculating plant of the type shown in FIG. 1.

However, in order to avoid this risk of contamination, according to the invention it is proposed to cool the wash water in a heat exchanger 105, where the coolant is uncontaminated water that circulates in the cooling tower with the help of a pump 107.

Another characteristic feature of the invention is not to convey water in liquid form from the plant, whereby the environment cannot be polluted from contaminants in this water.

The above means that the cooling water and the washing water circulate. i-, closed circuit in the plant.

On the installations shown in fig. 3>4 and 5>

the closed circuit in which the cooling and washing water flows is the following: Water from the cooling system 54 is transported by means of the pump 55 to the cooling devices 49 and/or 50 in the chamber 22 and towards the condensation devices for steam and washing of the flue gases, located in the chamber 17 and equipped with cooling water nozzles 45 Pa fig*

3, cooling water films 46 in fig. 4 and bubble-through vessel 48 Pa fig. 5.

The wash water and the condensed steam containing impurities, fibers and binder pass through the openings 24 and 25 at the bottom of the chamber 17 and the separator 18 out into a collector 26

which leads the water to a filtration plant 51 where the washing water is separated from solid impurities 56 in suspension, fibers and insoluble binder components.

This waste is collected on the conveyor belt 57* The filtered washing water then only contains contaminants and binding agent in dissolved form and this water is sent using gravity or a pump. 53 to a treatment station 54»

The applicant has established that when the wash water circulates

in a closed circuit, it must be ensured that the concentration of dissolved or suspended substances in the filtered washing water is kept below a certain level, approximately 0>, calculated on the basis of dry matter weight per water weight. Above this level, part of the dissolved or suspended substances in the wash water (essentially microfibres and/or microparticles of binding agent which are not captured by the filtering element 51" and dissolved binding agent components) will settle in the different parts of the facility. The binder will polymerize and form viscous or solid coatings which will eventually re-clog the nozzles in the organs 45>49°g 50°g the openings in the receiving organ 15 that let the flue gases through 29. You get a reduction in the amount of flue gas through the hood and the cooling of the flue gases as in within a short time means that the plant must be stopped.

In order to be able to keep the concentration of the water pollutants in the circulation water below the desired limit, relatively large amounts of solid pollutants must therefore be removed. A relatively large part, approx. 20 to 30$, of the binder that is atomized against the fibers from the body 13 will pass into the wash water in a method as described. For larger factories, this means that 3,000 to 5,000 kg are supplied per day of binder (calculated as dry matter) in the closed circuit formed by the washing water, and to maintain the desired state of equilibrium, equal amounts of binder must be drained out. There are several elimination methods: One of the methods consists in treating at least part of the washing water in a centrifuge which can separate out much more finely divided suspended solids than the filter 51 can. The water treated in the centrifuge 58 can be recycled to the container 52 as shown in fig. 3 or, more advantageously, sent back to the coolers 49*

Another method consists in treating the water by adding a precipitant and separating the excreted substance.

These two methods have the disadvantage that they only remove insoluble substances from the water. Dissolved binder, which makes up the majority of the pollutants, is only affected to a small extent;

The invention proposes several methods for the separation of dissolved binder in the washing water. Such a method consists in using the filtered or centrifuged washing water to dilute the binder for the production of adhesive water which is sprayed onto the fibers using the nozzle system 13. The withdrawal of filtered water can take place at any point in the circuit after the cooling system 54 or more favorable after the centrifuge 58, for example as shown in fig. 3, through the valve 59.

Another method consists in using the washing water as a cooling liquid for the fibre/gas flow 12 in the chamber 22. The washing water is then atomised towards the fibre/gas fat flow through the cooling nozzles 49 in fig. 3 or 50 in fig. 4..

The two methods have the advantage that they enable the recirculation of part of the binder in the wash water, and it is a feature of the invention that. the amount of binder that is sprayed through the glue application nozzles 13 is regulated as a function of the amount of binder that the mat during formation, 23, retains in the water spray that is sprayed on through the bodies 49 or 50, which enables a better utilization of the glue, but these methods do not make it possible to extract sufficiently large binders from the wash water so that the concentration of binder falls below the desired limit. Therefore, according to the invention, it is proposed'

two methods which complete the elimination of the significant amounts of binder dissolved in the water by circulation in a closed circuit.

One of these methods consists in burning a small part, of the order of 1 to 5%, of the water supply to the circulation circuit, in a suitable plant 60. This plant is shown in fig. 4> is of a known type and comprises: a burner 6l which is supplied with an air-fuel fuel mixture, an atomizing nozzle 62 through which the water from line 63 is sprayed out as a mist under pressure into the burner flame 6l by means of atomizing air 64,

a reaction chamber 65 where the treatment of the washing water takes place at the temperature that occurs during combustion in the burner 6l. The method consists of first evaporating the washing water and then heating the steam and the accompanying substances to a temperature of approx. 800°C, which is sufficient to convert the binder contaminants into non-polluting chemicals such as COg and HgO.

The formed non-polluting steam goes to pipe 66

with high temperature so as to avoid fog formation.

The point for draining this water to be treated is usually between the pump 53 and the cooling system 54'

as shown in fig. 4"

The specified method has the advantage that all the binder components in the wash water are treated and converted into non

polluting elements. The disadvantage is a significant energy consumption, which is consequently expensive. The additional cost that is thereby imposed on the produced fibers can be reduced by recovering part of the amount of heat contained in the high-temperature steam in a heat exchanger that produces superheated steam for various purposes.

The second method mentioned above consists in subjecting a small part of the washing water, of the order of 1 to 5$-, to a thermal treatment in such a way that the binder content is made insoluble and then separated from the water in a suitable way such as e.g. filtration, precipitation, centrifugation etc.

The applicant has found that if the water used for cooling and washing the flue gases and which after filtration contains binder and dissolved binder components is kept at a certain temperature for a certain time, a certain part will be converted into insoluble substances, in increasing amounts with temperature and time, and consequently pass to a suspension in water from which the solid can be separated.

The relative amount of the dissolved substances that are made insoluble by this heat treatment will determine the effect of the treatment.

The treatment temperature has a very important effect on the effect or yield, e.g. it has been found that for water containing 1% dissolved binder compounds, the performance of the treatment will be:

40$ if the water is kept for 8 days at 40°C,

40$ if the water is kept for 3 days at 70°C,

40% if the water is held for 3 minutes at 160°C,

60% if the water is held for 3 minutes at 180°C,

95$ if the water is held for 3 minutes at 240°C.

Fig. 6 shows the precipitation effect as a function of the treatment temperature. and the time.

In larger factories for the production of fiber boards, the amount of water to be treated can be 50 m-^/hour and, in order to avoid the construction of larger treatment plants, one must work with the shortest treatment times and higher temperatures of over 100°G. This will again require that the treatment is carried out under pressure, at a temperature that is maintained at approx. 5°C lower than the water's boiling point under the selected pressure so that the water remains in liquid phase during the treatment. This solution has, among other things, the advantage is that it only requires relatively little energy, namely, apart from the heat losses, the amount involved in heating the water to the selected temperature.

Under the assumption of an equal amount of dissolved binder, the latter method is four times cheaper than the incineration process previously discussed.

One of the disadvantages that is usually encountered when heating water containing binder or dissolved binder components, even in low concentrations, is that an insoluble coating is deposited on the walls of the vessel which very quickly becomes sufficiently thick to seal the vessel's openings.

In this connection, the applicant has found that if the required quantity for the heating is delivered in the water itself to be treated and the walls of the vessel during the treatment are kept at a lower temperature than the mass of water being treated, such a deposit on the walls will not occur as the precipitated or insoluble binding agent keeps itself in suspension in the water. A result of this is that the heating is then advantageously carried out either by mixing the water with hot gases, especially superheated steam or combustion gases from submerged burners or by means of organs that release energy in the water in another way, such as e.g. by an electric arc.

A wide range of processing conditions is possible, e.g. 6 to 40 atmospheres pressure, 160 to 240°C treatment temperature and from 3 to 10 min. treatment duration.

The conditions below seem to be a good compromise between energy costs and installation costs:

Implementation of the method can take place in apparatus that works discontinuously or continuously.

Fig. 7 shows a plant for discontinuous operation. The water that is treated is introduced through the controlled valve 67 to the chamber -68. The introduced amount of water or charge makes up 70 to 80% of the tub's capacity. The heating medium, preferably superheated steam, is then let into the vessel through the nozzle 69 which is immersed in the water. The amount of steam is regulated by the controlled valve 70, via regulator 71"

The order of treatment is:

The container 68 is filled with water under atmospheric pressure.

The desired treatment pressure is applied to the regulator 71, e.g. 16 atm.abs.

The valve 70 is opened and steam flows in through the nozzle 69, mixes with the water and transfers to the water its condensate while releasing condensation heat and coolable heat.

The temperature in the pressure vessel 68 rises to approx. 200°C under a pressure of 16 atm.abs.

The steam supply is then interrupted. The supply nozzle 69 is so large that said temperature and pressure increase is rapid, within less than 1 minute. The water is kept at 200°C and 16 atm.abs.

for 2 to 4 min.

After this time, the pump 72 is put into operation and sends a new charge of water to the container 73 through the double-walled channel 74. During the flow through the double jacket, the water, which has a temperature of approx. 40°C at the inlet to cool the treated water in the container 68. The dimensions of the heating jacket 74 are adjusted so that the water reaches the collection vessel 73 at a temperature of approx. 80°C.

An additional cooling liquid circulates in the second double jacket 74° and further cools the water in containers 68. The cooling is considered finished when the temperature of the treated water has dropped below 100°C, preferably 40 to 50°C. When this point is reached, the valve 76 is progressively opened to release the pressure in the container 68.

The treated water flows to a filtration station 51 or a facility for precipitation, decantation or centrifugation, where the precipitated binder components are separated from the water. The filtered water flows to the tub 52 and the dry matter 56 is sent to the conveyor belt 57*

When the container 68 is empty, the st eng's valve 76 and the valve 67 are opened for the preheated water in the tub 73 which flows per gravity into the container. An exhaust valve 67a is also connected to the plant.

Then a new cycle can start.

Fig. 8 shows a plant for continuous operation of it

proposed procedure.

During treatment, the pump 77 sends jets of water with impurities to the mixer 78 into which a heating medium such as e.g. water vapor. The steam mixes with the water to be treated, and during condensation transfers its entire amount of heat to the water. The amount of water vapor is regulated by the valve 80 which is controlled by the regulator 8l, so that the water at the exit from the mixing device 78 has the desired treatment temperature. At the exit from the mixer 78, in which the water has remained for 10 to 20 seconds, the water goes to the reactor 82 where the insolubilization or precipitation of the binder takes place,

and whose dimensions are adjusted so that the residence time for the treatment water is the desired treatment time of 2 to 4 min.

At the exit from the reactor, the water in the heat exchanger 83 is cooled to a temperature of below 100°G, preferably 40

to 50°C. Part of this cooling is achieved by the water to be treated being preheated in the spiral 84 from approx. 40 to 80°C.

The remaining cooling is effected by a cooling medium that circulates in the circuit 85.

At the exit from the heat exchanger 83, the pressure on the water is released up to atmospheric pressure through a relief valve 86 which, via a regulator 87, maintains the treatment pressure in the installation.

The water, which now has atmospheric pressure, goes to a filtration plant 51 - or a similar plant for precipitation, decantation or centrifugation which separates the water from the precipitated binder components. The filtered water goes to the container 52 and the waste 56 after treatment is sent to the conveyor belt 57-

The plant in fig. 8 which is operated continuously can be controlled in a more variable manner and is less expensive than the plant shown in fig. 7.

Yet another method consists in letting part of the washing water containing the contaminants undergo a bacterial treatment in a pool with air bubbles. In such a pool, certain bacteria will enzymatically cause a breakdown of the phenolic compounds in the water in particular. The treatment corresponds to a total oxidation reaction and converts the phenolic compounds in particular into non-polluting components such as CO^ and HgO. For the reaction to be complete as mentioned, the bacteria must be supplied with the necessary oxygen by blowing air through the pool.

The various plants for the production of pressed fiber boards and the like deliver many different types of waste, but all of them contain binder or binder components as contaminants.

First, one can mention records that have been discarded during quality control. Such waste is very well defined but voluminous. Then there is waste from the filtration of cooling water and washing water, containing fibers and a high concentration of binder and binder components. All such waste has so far been stored in less fortunate containers, and this practice now seems to be banned due to the risk of contamination.

According to the invention, a method for converting the waste into non-polluting components is provided. The method consists in treating the solid waste after a previous pre-treatment by means of a heat treatment, more specifically incineration, which transfers the polluting elements to non-polluting elements such as GO^ and HgO.

Fig. 9 shows a plant for carrying out this aspect of the invention.

The waste 56 from the heat treatment plant and the filtration plant is carried on the conveyor 57°g and falls into a crushing machine 88 where the waste is mixed with other waste in the form of glued fiber products 87 from the product line.

From the mixer 88, the mixture goes to an incinerator 90 on the conveyor belt 89. The heat released by the burner 91 brings the temperature of the waste up to 1000°C. At this temperature, the binder and its components are converted into non-polluting chemicals such as HgO and G02 and are led to the atmosphere together with the combustion gas from the burner 91, via pipe 93. The fiber material that is softened by the heat is collected at the bottom of the furnace, 90, and drained through the hatch 92 as a viscous thread which cools in the vessel 94 which is filled with water. The cooled material takes the form of granules and can be regenerated into fibres.

Fig. 10 shows another facility for processing such waste.

The mixture of waste 56 and 87 that comes out of the crusher 88 is sent on the conveyor 89 onto a cloth 94 which passes through the furnace 95. The furnace contains jet burners or electric resistance elements 96 which bring the temperature of the waste up to 600 to 700°C. At this temperature, the binder and binder constituents in the waste are converted into non-polluting constituents such as C02 and H^O which go to pipe 97 *The fibers which make up the majority of the waste soften' under this influence and partially fuse together into plates 98 with a volume which is much smaller than the output volume of the waste. These plates can then be reintroduced into the fiber production circuit.

Another characteristic feature of the invention is the reduction of the noise originating from the receiver in the described facilities.

In the facilities described, the worst source of noise is the fiber former, and more particularly the nozzles which blow out gases at high speed. The sound level around such a fiber forming plant, in the area where the workers must be, will usually be higher than 100 decibels. The design of the zone that surrounds the sound source in open facilities as shown e.g. on fig. However, 1 does not enable any. effective isolation of the sound source in relation to the external environment, because there is a free space with significant dimensions where secondary air enters. On the facilities shown in fig. 3 and 4j according to the invention, the closing wall 32" which delimits the opening 33 through which the fiber/gas mixture 12 flows down into the chamber 22, and the other walls 21 corresponding to this, is given such a shape that soundproofing plates 99 can be placed inside the chamber 22 and sound-insulating plates 100 outside the chamber'22.

The noise level is then reduced around the fiber former 11 to

20 to 30 decibels, which significantly improves the operators' working conditions.

Another source of noise is caused by the suction fan for smoke gases, 19. The sound energy is transferred via the smoke channels to the pipe, which sends the sound waves on to the surrounding environment.

In facilities as shown in fig. 1 has the large quantities of gas that must be led to pipe 35, and the need to reduce the pressure drop, required the installation of a pipe with a large cross-section, directly from the outlet of the fan 19, which causes the pipe to radiate almost all of the sound energy from the fan.

-. According to the facilities shown in fig. 3 and 4, according to the invention, the small flue gas volume makes it possible to extend the distance between the outlet for the flue gases and the fan 19. The outlet is placed on the recirculation channel 34 at a point separated from

the fan 19 with at least one pipe bend and a sufficiently long pipe length so that part of the sound energy from the fan 19 is absorbed in the duct 34"

The reduction of the noise level in the area around the pipe 35 can be 10 decibels or more.

Fig. 11 shows an overall plant according to the invention and comprises:

- A fiber former 101 where molten material 102 is introduced into a rotating body at high speed, which body is provided along the circumference with a series of openings from which the material is ejected by the centrifugal force. The material threads that are formed are deflected by means of an annular gas flow which. with great speed is directed downwards and which deflects and stretches the fibers into fine threads. - A distribution device for fibres, consisting of a reciprocating sleeve tube 14 which receives the fibre/gas flow 12 from the fiber former. - A cooling device comprising atomizing nozzles 50 which atomises cooling water towards the fibre/gas stream 12. This device is placed between the distributor 14 and the glue applicator 13. - A mat former 15, the receiving device, which consists of a perforated cloth. - A receiving chamber 22 of rectangular shape, limited in the lower part by the perforated cloth 15, in the side by the vertical walls 21 and in the upper part by a horizontal wall 32 which is located at a distance of 200 mm below the fiber former 101 and encloses an annular opening 33 through which the gas/fiber flow 12 passes. The edges of the opening are deflected like this. that the inlet of the fiber/gas flow 12 is facilitated, tangentially with the gas flow. The vertical walls 21 define above the perforated cloth 15 the forming zone for the mat. - A suction box 16 placed under the perforated cloth 15, where a negative pressure is maintained with the help of the fan. 19. - An expansion and washing chamber 17 placed after the box 16, comprising atomizing nozzles 45 which are arranged so that they form a mist of microdroplets in the channel for the flue gases 29. - After the chamber 17 a water separator 18 of the cyclone type. - A fan 19 which forces all the gas that follows the fibers from the receiving body 15 to go through the fan and carries the gas on through the channel 34• - A recirculation channel 34 where the rear part opens out at 36 in the upper part of the chamber 22, in the zone that surrounds the fiber front -divisor 14. The quantity of recycled flue gases is approx. 90 to 95$ of the amount of flue gas that passes through the receiving member 15 and is supplied to the chamber 22 through the opening 36 and again from the recirculation channel 34. - A pipeline 35 which is branched from the channel 34°g which leads to the burner plant 39" where 5" to 10% of the flue gases which have passed through the receiving member 15' undergo a combustion process. After undergoing the combustion, where the gases are heated to approximately 600°C, the clean gases are led to the pipe. rrSound and heat insulating plates 99 °S 100, placed on the walls 31 °S 32 in the zone that lies around the fiber former 101,. - A collection chute 103 which collects washing-cooling water contaminated with fibers and binder as well as binder components, dissolved or suspended, which comes from the openings 24 and 25 at the bottom of the chamber 17 and the cyclone -18. - A pump 104 which continuously pumps water from the gutter to a filtration plant $ 1. - A filtration plant 51 of the mask-vibration filter type, which separates insoluble waste from the washing water.

A vessel 52 placed below the filter 51°g which collects the filtered water. - A heat exchanger 105 where the water from the vessel 52 circulates by means of. the pump 53°g is cooled while releasing accumulated heat from the flue gases 29 as these have passed through the chamber 22 and 17 and the suction box 16. - A cooling tower 106 where the cooling water from the heat exchanger 105 circulates with the help of the pump 107" - A pump 55 which circulates the water from the vessel 52 to the cooling nozzles 50 for cooling the fiber/gas stream, to the condensation and washing nozzles 45 for the flue gases 29, to the gluing station 108

and to the water treatment department 109.

- A station for treating water 109, where the water under a pressure of 16 atmospheres maintained by the pump 77. passes through a heat exchanger 83 where the water is heated to approx. 80°C.

At the exit of the heat exchanger, the water enters a mixer 78 where it is mixed with preferably superheated steam which increases the mixing temperature to 200°C, where the temperature is maintained for 2-4 min. in the reactor 82, which is arranged after the mixer 78. At the exit from the reactor 82, the treated water is cooled to a temperature of 40 to 50°C and is decompressed to atmospheric pressure in the pressure equalizer 86, and is led to a centrifuge 110 which separates out the dissolved binder from the treated water. The purified water is sent to the container 52.

- A fresh water supply 111 which flows into the tub '52

and how to keep the amount of water constant in the plant.

- Transport means 57°g 112 which carry waste from the filtration post 51°g water treatment post 109 and from the manufacturing lines, to the station for waste treatment 113»

- A station for processing waste 113>consisting of

of an oven equipped with gas jet tubes, or electric resistance elements where the waste is heated to 600 to 7OO0C, so that the binder is burned and the fibers are fused into small plates which can then be replenished in the fiber production circuit.

Fig. 12 shows another plant according to the invention, which comprises:

- A fiber former where the molten material, especially glass, flows out of a spinning nozzle 114 as threads 115, which solidify before contact, with stretching rollers 116 which introduce the solid fibers into a hot gas stream at high speed, 117, usually approximately at right angles with the gas flow. The lower end of the hanging fibers softens and the hot gas stream stretches the fibers and throws them towards the mat former as a fiber/gas stream 12. - Et. cooling device comprising atomizing nozzles 50 that atomize cooling water on the fiber/gas stream 12. - A gluing station 113 that atomizes binder in the fiber/gas stream 12, arranged after the cooler, counted in the direction of flow.... - A mat-forming device 15, in the form of a perforated cloth.

-A receiving chamber 22 of rectangular shape is limited*

in the lower part of the perforated cloth 15, in the lateral direction of the vertical walls 21 and at the top of the wall 32, as well as in the front part delimited

of the vertical wall 118 arranged approx. 200 mm from the nozzle opening 117 and provided with a rectangular opening 33 through which the stream 12 passes. The edges around this opening are profiled

so that the inlet of the flow 12 is facilitated, as the edges are deflected tangentially to the flow 12. The vertical walls 21 delimit the mat-forming zone on the cloth 15.

- A suction box 16 arranged under the perforated cloth

15, under the mat forming zone.

A washing chamber 17 placed under the suction box 16 and provided with openings 47 which open below the surface over a certain amount of water 48 as the flue gases. 29 flows through. The nozzles 45 are supplied with washing water which - an overflow 24 leads to the collector channel 26. - After the chamber 17 a water separator 18 of the cyclone type.

- A fan 19 which sucks in the accompanying gas for the fibres

and sends the gas on to channel 34"

- A recirculation channel 34 where the rear part opens out

in the chamber 22 through two openings taken out in the vertical walls 21 on both sides of the fiber former in a zone around it. The recycled flue gas quantities can be 95$ of the flue gases through, the perforated cloth 15, and these gases are sent to the chamber 22 through said openings.

- A pipeline 43 which is branched off from the chamber 22

in an area which is located in the rear part of the chamber, and which, with the help of the fan 44, delimits part of the uncirculated flue gases, to the combustion plant 39* ....

- Sound-insulating and heat-insulating plates 99 and 100 placed on the walls 21, 32 and 118 in the area around the fiber former. - A collector chute 103 which collects washing-cooling water contaminated with fibers and binder components, dissolved or in suspension, which comes from the openings 24 and 25 in the lower part of the chamber 17 and the cyclone 18 resp. - A pump 104 which leads the water from the collecting chute to the filtration system 51»- A filtration system 51 of the mask-vibration filter type, which separates insoluble waste from washing water. - A container 52 placed under the filter 51, which collects filtered water. - A heat exchanger 105 where the water from the vessel 52 circulates with the help of the pump 53°S is cooled while releasing accumulated heat from the gases 29 when they flow through the chamber 22 and -17"

The facility described is also equipped with a water treatment station and a waste treatment station, similar to the one described in connection with fig. 11.

Fig. 13 still shows a plant according to the invention, which comprises: - A fiber former where the molten material flows from a pre-container 118 i - an oven through the openings in a thread-drawing nozzle 119j provided with many holes, which form a large number of threads which-then flows down into a stretching zone where the material passes gas streams which. giving them a high speed. The nozzles 120 for these gas streams are arranged close to the glass threads and the gas streams wind the threads downwards practically parallel to the thread direction. Most often, the gas streams consist of high-pressure steam. The produced fibres, the stretching gas and secondary gases together form the fibre/gas stream 12.

- Coolers 50 which spray cooling water against the current 12.

- A gluing station 13 which sprays binder into the fiber/gas flow 12. -- A fiber distributor 14 which comprises two compressed air nozzles, for directing the fibers in the desired direction.

The plant shown in fig. 13 is otherwise analogous to what is shown in fig. 11... .Fig. 14 still shows a plant according to the invention, which comprises:

- Single fiber forms where the material is in molten form and

as threads 121 fall towards the circumference of a rotor 122 which rotates at high speed, controlled by gas flows coming at high speed from the openings 123. The rotating body 122 converts part of the collected material into fibers by means of the centrifugal force and throws the fibers over towards .another rotor 124 which converts a part of the occupied material into fibers in an analogous manner. The number of type 124 rotors is usually limited to two or three. Through a ring of openings 125, surrounding the rotors 122 and 124,

flows gases at high speed, which tear with them the produced fibers to a receiving organ. The gases consist of compressed air or high-pressure steam.

In general, the opening 125 is used for applying binder to the fibers.

The mixture of fibres, blowing gases and secondary gases forms the stream 12.. - A cooler system 50 which atomises cooling water towards the stream 12, placed after the opening 125, and some of which apply binder.

The plant in fig. 14 is otherwise the same as in fig. 12.

Claims (1)

1. Procedure for the elimination of pollution factors in gaseous, liquid and solid waste substances and reduction of noise in connection with the production of mat or board products from mineral fibres, especially glass fibres, where the fibers at the exit from the fiber production facility undergo a gluing process using a binder which contains or emits polluting components and is deposited on a receiving body in the form of a mat or plate, characterized by the fact that the flue gases are partially recycled - (together with; production gas from the fiber former, sucked in secondary gas - and accompanying pollutants) so that the gases are made to pass the fiber product several times while it is being formed, that most of the heat from the fiber production facility is heat exchanged to water that is cooled, that the flue gases are washed with water after they have passed through the fiber product and the receiving organ, whereby part of the pollution components in the flue gases pass into the water, it cleans part of the flue gas ne that is not recycled, before draining to the pipe, recycles at least part of the washing water, a certain part of which has undergone treatments for the separation of a significant part of the pollutants, and that the solid waste undergoes cleaning processes... 2.. Method as stated in claim 1, characterized in that the amount of flue gases that are fed to the pipe is essentially equal to the amount of gas that is introduced through the fiber former as blowing gas. 3« Procedure as specified in claim 1, characterized by water coming out. the plant only in gas phase. 4. Method as specified in one or more of claims 1 or 2, characterized in that the recycled flue gases are introduced into the fiber production zone and between the production zone and the fiber receiving zone follows a path that runs essentially parallel to the blowing gases. 5* Method as stated in claim 1 or 2, characterized by ..that the branching zone to the atmosphere for non-recirculated flue gases is arranged in the recirculation channel for the flue gases at a certain point that the noise emitted to the surroundings from the outlet organ for the flue gases is significantly reduced . 6. Method as specified in claim 1 or 2, characterized in that the washing water undergoes a heat treatment, whereby the water is heated in steam form to between 500 and 800°C for the removal of contaminants which are thereby converted into non-polluting components. 7. Method as specified in claim 1 or 2, characterized in that the wash water undergoes a bacteriological treatment which causes the breakdown of pollutants and converts them into non-polluting components. 8. - Process for de-solubilization (precipitation) of thermosetting resins such as. is contained in the water, characterized in that - the water is heated to a temperature which is preferably above 100°C, preferably between 150 and 24-0°C. 9« Method as stated in claim 8, characterized in that the treatment is carried out under pressure. 10. Method as specified in claim 8, characterized in that the required amount of heat is supplied to the water mass itself. 11. Procedure as stated in one or more of the requirements 8 to. 10, characterized by .at. the heat treatment is carried out in a container whose walls maintain a lower temperature than the water being treated. 12. Method as specified in one or more of claims 8 to 11, characterized in that the treatment is carried out by introduction of combustion gases from a burner which is submerged in the water. 13. Method as specified in one or more of claims 8 to 11, characterized in that the treatment takes place by heating with an electric arc immersed in the water. 14« Method as specified in one or more of claims 8 to 11, characterized in that the treatment takes place by introducing preferably superheated water vapor into the water. 15. Method as specified in one or more of claims 8 to 14) characterized in that the methods are applied to the method in one or more of claims 1 to 5 > for treatment of washing water.. 16.' Method as stated in one or more of claims 7 to 15, characterized in that the water is filtered after treatment to remove solid components and precipitated compounds. 17.- Method as specified in one or more of claims 7 to 15, characterized in that the solid substances .and precipitated compounds in the treated water are separated from the water by decantation, possibly after flocculation. 18.. Method as specified in one or more of claims 7 to 15, - characterized in that. the solids and precipitated compounds from the treated water are separated by centrifugation. "- 19" Process as specified in one or more of claims l6 to l8, characterized in that the precipitated substances are burned in an oven, preferably between 600 and 1000°C, and that the precipitated substances are converted by this treatment into non-polluting components . 20. Method as stated in claim 1, characterized in that the amount of heat supplied through blowing gases and the fiber material is brought out of the plant by means of a cooling medium, especially water. 21. Method as stated in claim 1, characterized in that water is brought into contact with the fibers and the flue gases to be cooled, which water is at least partially evaporated when meeting the hot fibers and gases and essentially as steam is transported together with the flue gases to a zone where the steam is condensed and cooled. 22. Method as specified in claim 20 or 21, characterized in that the transfer of heat and pollutants from the flue gases to the water is increased by providing a large contact surface between flue gases and water. 23. Method as set forth in claim 22, characterized in that said large contact surface between flue gases and water is achieved by atomizing the water as a mist in the flue gases. 24. Method as stated in claim 22, characterized in that said large surface is achieved by bringing the water to flow as thin layers in contact with the flue gases. 25. Method as stated in claim 22, characterized in that said large contact surface is achieved by causing the flue gases to bubble through the water. 26. Method as specified in claim 20 or 21, characterized in that the transfer of heat from the flue gases to the water is increased by atomizing the water into the flue gases in an area where the temperature of the flue gases is high. 27. Method as set forth in claim 26, characterized in that the water is atomized as small droplets into the flue gases and onto the fibers in an area located between the fiber former and the receiving zone for the mat or plate. 28. Method as stated in claim 26, characterized in that the water is atomized into the flue gases and onto the fibers between the fiber former and the glue application device. 29. Method as stated in one or more of claims 20 to 28, characterized in that the water used comprises recycled water containing dissolved contaminants of binder. 30. Method as stated in claim 29, characterized in that the amount of binder that is sprayed onto the fibers is reduced, as a function of the amount of binder that is dissolved in the wash water and is collected by the fiber mat. 31» Method as stated in one or more of claims 20 to 25, characterized in that the water is atomized in the flue gases after these have passed the mat or plate which is being formed. 32. Procedure as stated in one or more of the requirements §1 to 31, characterized in that the cooling of the water is carried out in a room which is not in contact with the atmosphere. 33" Method as stated in claim 1, characterized in that the amount of binder that is sprayed onto the fibers is reduced, as a function of the amount of binder found in the recycled flue gases. 34• Method as stated in claim 3> characterized in that the export of washing water is avoided by using part of the washing water after filtration for the production of glue mixture. 35. Method as stated in one or more of claims 1 or 2, characterized in that the non-recycled part of the flue gases is heat-treated to convert polluting components into non-polluting components, particularly by direct or catalytic combustion. 36. Method according to claim 1 or 2, characterized in that the non-recycled part of the flue gases undergoes an electrostatic cleaning. 37» Method as stated in claim 1, characterized in that the solid waste undergoes a heat treatment at over 1000°C where the pollutants are converted into non-polluting components and the mineral products melt and are converted into components with a greatly reduced volume. 38. Method as stated in claim 1, characterized by subjecting the solid waste to a heat treatment at a temperature above 600°C where the pollutants are converted into non-polluting components and the mineral substances are fused into plate-like products. 39" Method for carrying out the method as stated in claim 1, characterized in that it comprises the following organs: a fiber former, a chamber which surrounds the fibers between the fiber former and the fiber receiving member and which is provided with an opening through which the flow of fibers and blowing gases from the fiber former passes into said chamber and where the edges around said opening are deflected tangentially to the fibres/gas flow, a device which enables the introduction and uniform distribution of recycled flue gases into the chamber, means for supplying water and for joining with the flue gases, a means for separating the water from the flue gases, means for cooling the water, a fan arranged after the fiber receiver, a connection channel between the fan and the introduction device for flue gases in the chamber, for recirculation of a part of the flue gases, as well as a channel that branches the non-recycled part of the flue gases into a smoke treatment plant before the latter goes out into the atmosphere. 40. Apparatus as specified in claim 39" characterized in that the water atomization nozzles are arranged between the fiber former and the fiber receiver. 41. Apparatus as stated in claim 40, characterized in that the water atomization nozzles are arranged between the fiber former and the glue application device. 42. Apparatus as specified in one or more of claims 39 to 41" characterized in that the water atomization nozzles are arranged after the fiber receiver. 43" Apparatus as specified in one or more of claims 39 to 42, characterized in that said surfaces where a thin film of water flows are placed in the flow path of the flue gases. 44* Apparatus as specified in one or more of claims 39 to 42, characterized in that pipelines introduce the flue gases at a level lower than the surface of the wash water into a suitable vessel arranged after the fiber receiver. 45» Apparatus as stated in claim 39 ^1 44>characterized by organs that clean at least part of the washing water from contaminants by a suitable treatment. 46. Apparatus as specified in claim 45>characterized in that the means for separating solids from the wash water is a filter, centrifuge or decanting system, optionally associated with a precipitation means. 47* Apparatus as specified in claim 45> characterized in that the methods used consist of heating. 48. Apparatus for carrying out the process as stated in claim 8, characterized by a boiler where the water is heated under pressure to a temperature of preferably above 100°C, and a reactor where the resin in the water is rendered insoluble (precipitated). 49" Apparatus as stated in claim 48, characterized by means where the water is heated under pressure by mixing with a hot medium, especially water vapour. 50. Apparatus as stated in claim ^( characterized by a device where the water is heated under pressure by means of a submerged electric arc. 51. Apparatus as stated in claim 48> characterized by a device which heats the water under pressure by means of a submerged burner. 52. Apparatus as specified in one or more of claims 48 to 51> characterized in that a heat exchanger where the treated water gives off part of its heat energy to the water to be treated. 53" Apparatus as specified in one or more of claims 48 to 53" characterized in that it is used for the treatment of washing water' after washing flue gases in a facility as specified in claim 39* 54* Apparatus as stated in claim 47> characterized by a burner which evaporates the washing water and brings the steam temperature up to between 500 and 800°C. 55* Apparatus as specified in one or more of claims 39 to 54 j characterized by a heat exchanger for cooling the water. 56. Apparatus as specified in claim 55" characterized in that the heat exchanger consists of a cooling tower. 57" Apparatus as specified in one or more of claims 39 to 47° g 53 to 56} characterized in that the means for separating the water from the flue gases consists of an expansion chamber or of a cyclone or electrofilter. 58. Apparatus as specified in one or more of claims 39 to 47 and 53 to 57, characterized in that the opening in the chamber surrounding the fibers, through which the fibers and blowing gases enter said chamber, is located at such a great distance from the fiber former that the length that the fiber-gas mixture from the fiber former must travel in free air is as small as possible and preferably below 200°mm. 59* Apparatus as specified in claim 58, characterized in that the shape of the chamber surrounding the fibers is such that the flow distance for the blowing gases through free air is equal to zero. 60.. Apparatus as specified in one or more of claims 39 to 47 and 53 to 59 s characterized in that the inlet to the branch for non-recycled flue gases, which must be cleaned, is placed at a point on the connection channel between the fan and the chamber around the fibers. 51. Apparatus as specified in one or more of claims 39 to 47 and 53 to 60, characterized in that the inlet to the pipe for the recirculated flue gases is placed in the recirculation channel at a point that is at a sufficiently large distance from the fan and separated from this by at least one pipe bend. 62. Apparatus as stated in one or more of claims 39 to 47. and 53" 59> characterized in that the inlet to the branch channel for non-recycled flue gases is arranged at a point in the chamber wall around the fibers. 63. Apparatus as specified in one or more of claims 39 to 47 and 53 to 62, characterized in that the chamber surrounding the fibers is sound-insulated by sound-insulating plates.