CA1069645A - Suppression of pollution in mineral fiber manufacture - Google Patents

Abstract

Abstract of the Disclosure Methods and equipment are disclosed for production of mineral fibers, by attenuation, involving the use of a substantial volume of gas, in which water is also employed at least in a fiber binder, the methods and equipment providing for recirculation of most of the gases, and preferably also of the water employed in the system. Both the gases and the water are purified and the pollutants are separated and are also treated to convert the pollutant constituents to a form not ecologically objectionable for disposal.
She method and equipment herein claimed is particularly concerned with the separation and disposal of pollutant constituents.

Description

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SUPPRESSION OF POLLUTION
IN MINERAL FIBER MANUFACTURE

In considering the following description it is to be kept in mind that certain portions of the subject matter disclosed are also disclosed and claimed in the companion application Serial No. 210,777 of Marcel Levecque and Jean A. Battigelli, filed October 4, 1974.

The present invention is concerned with a process, and the devices for implementing it, which assures the sup-pression of harmful factors and permits the elimination of at least the majority of the ecologically objectionable pollutant elements-- noxious or undesirable due to their toxicity, their odor, and their opaqueness--contained in the gas or liquid wastes discarded by installations manu-facturing mineral fibers.

The invention is of particular use in installations for the manufacturing of fiber blanket, mat padding, or boards of mineral fibers and especially glass, agglomerated by thermosetting or thermoplastic binders, which coat the fibers and/or bring about close binding between fibers in the finished product.

The binders commonly used in this type of manufac-turing have a base consisting of pure or modified phenoplast or aminoplast resins, since these present advantageous charac-teristics for the manufacturing of agglomerated fibrous products. They are thermohardenable, soluble or emulsifiable in water, they adhere well to the fibers, and are relatively low in cost.

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Generally, these binding agents are used dissolved or dispersed in water to which certain ingredients are added, in order to form the binder which is sprayed on the fibers.

Under the effect of the heat to which they are subjected during the fiber products manufacturing processes, these binders release toxic volatile elements having a per-ceptible pungent odor even at very weak concentrations, such as phenol, formaldehyde, urea, ammonia, and decomposi-tion products of organic materials.

Other binders are used for certain applications due to their very low cost. Certain extract of natural products are hardened by drying and cross linking, such as occurs with linseed oil upon oxidation. Others are thermo-plastic, as for example bitumen. During the fiber binding process, they are all, at least to some exten~, increased in temperature and to a temperature sufficient to cause the release of volatile elements, noxious or otherwise un-desirable, among other reasons, due to their odor.

In the text below, the word "binder" will be used to designate any one or all of the binding products mentioned above, whether they are used in liqu~d form, dissolved or suspended in water or in other liquid, or in an emulsion.

In a fiberizing plant, it is in the fiber collect-ing or ~orming section that large quantities of gases and water have contact with the binder which contains the pollu-tant elements, and are contaminated according to a pollution ,,~3 , .. .
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process which is common to all known processes for the manu- ~ -facture of blankets, mats, or boards of fibers agglomerated by a binder, and which will now be described.

a) The pollution of the gaseous effluents takes ~-place according to the following process:
'.,' .; ' The binder is projected into the current made up of fibers and gases, coming from the fiber production apparatus, the binder being present in the form of clouds of fine droplets. Some of this binder is entrapped by the fibers, some is unavoidably deposited on the walls of the installation, and finally some is found in the gases or fumes in the form of fine droplets and in the form of vapor.

Thus two fluid contamination modes coexist, the one consisting of contamination by droplets of the binder and the other consisting of contamination by vapors of the binder. In the binder application, the binder atomization or dispersion devices used furnish particles or droplets within a very wide range of diameters. The finest droplets are not entrapped by the fibers and are drawn through the blanket being formed by the gaseous current, in which they are present in suspension.

The droplets of binder deposited on the fibers during the binder application are subjected to the kinetic effects of the gaseous current passing through the blanket being formed. A large quantity of droplets is extracted from the fibers, migrates through the blanket, and is found ' :, ' -. ' '............ . . :
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10~6~:~s in suspension in the exhausted gases.

Finally, the desire to obtain a homogeneous distri-bution of the binder in the blanket makes it necessary to disperse the binder in the fiber and gaseous current in an area situated near the fiber production apparatus, where this current still has a well-defined geometric form but where its temperature may still be high enough so that some of the binder, or at least its most volatile components, are evaporated. These pollutant vapors mix with the gases and contaminate them.

In the text below, the word "fumes" will be used to designate the gaseous effluents which pass through the fiber blanket and are evacuated outside of the collecting unit, i.e., the gases used for attenuating or guiding the fibers, the fluids induced by these gases, and the pollutant elements in the form of droplets or vapor suspended in these fluids. It is to be understood that various features of the invention, such as treatment steps and components of the apparatus, may be employed with "fumes" having a wide

2~ range of compositions and pollutants. It is preferred to treat all components of such fumes, but various features of the invention may also be employed with gases originating in fiber production operations in which the gases have pol-lutant components, whether or not the pollutants have their origins in fiber binders.

b) The functions performed by the water in a fiber collecting unit make a large degree of pollution in-evitable in any installation in which binders are used.

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In operation, water is used:
--(1) to dilute and carry the binder when the latter is used in liquid form;
--(2) to wash or scrub the fumes, an operation which consists:
--(2a) of causing the largest possible `
amount of pollutants contained in the fumes in the form of droplets or vapor to be captured by the droplets of the scrubbing water, thus causing the pollutant charge of the fumes to be transferred to the wash water;
- (2b) of capturing and entraining on the walls of the collecting unit the fibers suspended in the fumes;
--(3) to wash the different parts of the collecting installation (perforated belt, fume flues, etc.) in order to evacuate the binder and the fibers deposited therein.

During these operations the wash water is charged with binder components which are soluble, insoluble or in the vapor state, and the concentration of pollutant elements may reach hiyh values.

It is an object of the invention to render insoluble the thermohardenable resins contained in the water. These resins are rendered insoluble, according to the invention, by means of a heat treatment--preferably at a temperature greater than 100 C., and more advantageously ranging between approximately 150 and 240 C., and under pressure.

~ he application of the above process (for render-ing resins insoluble) to at least some of the cooling and washing water is advantageously used to render insoluble ~''' .

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the dissolved binder components contained in the water, in order to subsequently be able--by means of known techniques--to extract insoluable materials and thus to maintain the concentrations of the pollutant constituents in the washing and cooling waters at a level compatible with the continuous re-utilization of these waters in the installation. The wash water thus circulates in a closed circuit and any external rejection of pollutants with the wash water is eliminated.
In summary of the above, therefore, the present invention provides a method for separating water soluble but heat insolubilizable resin constituents from an aqueous solution thereof, which method comprises insolubilizing the constituents by heating the solution to a temperature between about 150C.
and about 240C., at an absolute pressure of from about 6 to about 40 bars, and thereafter separating the insolubilized constituents from ~he water.
The above method may be carried out in apparatus for separating heat hardenable resin constituents from an aqueous solution thereo~, comprising pressuriæed treatment equipment for heating the solution to a temperature sufficient to insolubilize the constituents and for maintaining the solution heated and under superatmospheric pressure for a time suf~icient to effect such insolubilization, the treatment equipment comprising a batch treatment vessel having means for heating the interior of a batch of the solution therein and having means for cooling the walls of the vessel during the heating, the pressurized treating equipment having an inlet for receiving pressurized solution to be treated and having an outlet for discharge of treated solution at atmospheric pressure, a supply source for solution to be treated, means connecting the supply source with the inlet including means for preheating the solution being supplied, and means recei~ing the treated solution ywl/~ 6 -. . - . . - ,- - - . ~ .
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discharged from the outlet and for separating the insolubilized ~ `
constituents from the heat treated solution at atmospheric pressure.
The drawings illustrate the general arrangement of fiber production installations and also several preferred embodiments of equipment according to the invention adapted to be used in such installations, all of the figures being at least in part diagrammatic and in general showing elevàtional or vertical sectional views.
Figure 1 shows a fiber collection installation of the general kind to which the equipment according to the present invention is applicable.
Figure ~ depicts the evolution of the efficiency level for the insolubilization treatment based on treatment temperatures and times.
Figure 3 shows a set-up providing for batch treatment of wash waters by heating under pressure, as is contemplated by the invention.

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ywl/~14~ - 6a -10~ s Figure 4 shows a set-up in continuous operation for treating the waters.

In Figure 1 the installation comprises a fiber production device, represented by 11, for instance of a known type such as is ordinarily used in installations for the manufacturing of agglomerated or bonded fibrous blankets, panels or boards, in which the material to be attenuated is subjected to the action of a centrifugal or àerodynamic force, or to a combination of the two. The aerodynamic force is applied to the material to be attenuat-ed or to the fibers by means of gaseous jets which are gene-rally at a high temperature and high speed. An example of such equipment is shown in Levecque U.S. Patent No.

3,285,723. The fibers produced leave device 11, dispersed in a current 12 of fluids generally in the gaseous state formed by high-energy jets and the air or other gases which they induce from the surrounding medium, a current which envelops the fibers and directs them, in the form of a stream with fairly well-defined contours, towards the collection device.

The equipment further includes a zone for application of binder, placed in the path of the fiber and gas current, between the fiber production device 11 and the collection device, in which atomizers 13 disperse the binder, in the state of a cloud made up of fine droplets, into the fiber and gas current. A large proportion of these droplets in-tercepts the fibers and clings to them, the remainder being present in suspension in the gases accompanying the fibers ~ -either in the form of droplets or in the form of vapors.
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A fiber distribution device which may be any one of several known types, indicated diagrammatically at 14, placed in the path of the fibers and the gases 12, either between the production device 11 and the binder application zone or between the binder application zone and the forming section, as is shown in Figure 1, which by imparting an oscillating movement to the current of fibers and gas or by deforming this current, makes it possible to distribute the fibers on the collection surface so as to form a blanket whose weight per unit of area is essentially uniform.

The collection surface is provided by an endless perforated belt 15, on which the fibers accumulate to form the blanket 23.

A chamber 16, placed beneath the perforated belt, in the area where the fibers are deposited and the blanket or mat is formed, i.e. the forming zone or section, and in which a pressure reduction or negative pressure created by a fan 19 causes all of the gases accompanying the fibers along their path between production device 11 and perforated belt 15 to traverse the blanket being formed, so that no fluid in the gaseous state is entrained with the fibers, outside of the area where the blanket is formed.

Vertical walls 21, which extend from the perforated belt 15 to a level near the fiber production device 11, and which mark off the area where the blanket is formed, define a section or chamber 22, surrounding the current of fibers and gas, open at its upper end, in an area near the fiber production device. This is commonly designated as the forming "hood".

$ ~ -8-106~;45 The fan 19, provides a negative pressure in chamber 16 sufficient to force all of the gases accompanying the fibers (as they are being deposited in the forming section) through the blanket being formed, and evacuates the fumes for recirculation as is described below.

In Figure 1, the upper part of receiving chamber 22 is closed by a cover 32 containing an orifice through which current 12 of fibers and accompanying gases coming from fiberization device 11 penetrates forming section 22.
The edges 33 of this orifice are tangential to current 12 and are of such a profile as to facilitate passage of the above-mentioned current.

For the sake of operating convenience, cover 32 may be placed at a distance H from fiberization device ll.

The set-up of Figure 1 consists of a washing chamber 17, placed dow~stream from the suction chamber 16 and generally larger in section than the latter, chamber, equipped with apparatus in which fumes 29--i.e., the gases accompanying the fibers between production device 11 and collection belt 15, and the pollutants in suspension--are placed in contact with a washing fluid, in particular water. In this washing chamber 17, the fumes are separated from a portion of the elements that they contain in suspension--the latter elements essentially consisting of fibers and the binder with which they are charged upon passing through the zone where binder is applied and the fiber blanket is formed. In contact with the washing water, the fibers contained in the fumes .. . . .. .. .. . .. - .

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retain droplets of water and subsequently have a tendency to be deposited by gravity on the bottom of chamber 17, this phenomenon being moreover accelerated by the abrupt reduction in speed of the fumes as a result of the variation in the flow section along their path of travel from chamber 16 to chamber 17. Some of the droplets or pollutant vapors are intercepted by the droplets of washing water, and are dissolved by this water. It is the functioning of these two operations together which constitutes the washing of the fumes. The water which was used for washing, and to which at least some of the pollutant charge of the fumes was transferred, is discharged through orifice 24.

This set-up also contains a separation system 18, of the cyclone or electrostatic type, placed between washing chamber 17 and the suction fan 19, in which the fumes are at least partially stripped of the water droplets with which they are charged during the washing operation, and which it is important to eliminate before entering fan 19. The washing water extracted from the fumes in the liquid form is evacuated from the separation system through orifice 25.

A collector 26 leads the washing water evacuated through orifices 24 and 25 towards the treatment zone.

As above mentioned, the current of fibers and gases passes the binder devices 13 and then fiber distribution device 14. The fibers are deposited on collection belt 15 and the fumes 29 ~ass through the fiber blanket 23 being ~ j~ .!, . ', ' . ' . .. . ' ' ' , . ' . ' ,, 1o6964s : :

formed, through chambers 16, and through water separating unit 18, and are driven upwards by a fan 19 into duct 34.
Some of these fumes are evacuated from the system through orifice 35. The rest are led through duct 34 towards form-.. . . .
ing section 22, into which they enter through an opening36 placed in a zone situated near the fiber production device 11.

The quantity of gas entering the forming section through opening 33 is equal to the sum of the quantity of gas coming from production device 11 and the quantity of air induced by the latter as they pass in the open air, along the length H. The quantity of gas entering the chamber therefore increases with the length H.

For the system to be in equilibrium, it is necessary .::
that the quantity of fumes evacuated from the system through discharge orifice 35 be equal to the quantity of gas entering the system through orifice 33. The quantity of fumes to be evacuated will thus decrease when the distance H is reduced.

In the installations built according to that repre-sented in Figure 1, the recycled quantities of gases correspondto the quantities induced by the jets coming from device 11, and this ~low of the fluids through the section 22 will take place in the direction of flow of the attenuating jets, and therefore in the absence of disturbing eddies. The recycled fumes essentially follow the current lines repre-sented by arrows 37.

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Provision may be made for treating the fumes evacuated through orifice 35 by burning, an operation which consists of heating the fumes to a temperature sufficient to burn organic components, preferably greater than 600 C.--beyond which the pollutants of the fumes, and especially the phenol compounds, are transformed by combustion into non-pollutant elements, such as CO2 and H20. This treatment also has the advantage of destroying odors. AS shown in Figure 1, the burning procedure takes place in device 38, of a known type, consisting of a combustion chamber 39, a burner 40 supplied with a combustible mixture, and pro-vided with a grid or any other flame stabilization device 41. The treatment temperature may be reduced to a value ranging between 300 and 400C. in the presence of a com-bustion catalyst.

The purified fumes are discharged to the atmospherethrough stack 42. At the outlet of stack 42, the temperature of the fumes is high enough, and due to recycling their output is small enough, so that the steam contained in these fumes is not condensed before total dilution of the fumes in the atmosphere. Thus no cloudy plume appears at the outlet of stack 42.

In the installations represented in Figure 1, since the small volume of fumes evacuated to the atmosphere only eliminates a very small quantity of heat, means are provided for cooling the forming section 22.

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In the arrangement represented in Figure 1, atomizers 45 disperse cooling water in the form of sheets or curtains of fine droplets, these sheets being generally perpendicular to the direction of flow of fumes as indicated at 29. Once the fumes have traversed the fiber blanket being formed, they enter chamber 16 at a temperature on the order of from 80 to 100C. and are cooled by contact with the sheets of water to a temperature on the order of 30 C. The tem-perature of the water at the entrance to atomizers 45 is on the order of 15 to 20 C., according to the capability of the cooling devices serving to supply the atomizers.
By contact with the fumes, the water is reheated to a tempera-ture on the order of 30 to 40 C., according to the flow rate through the atomizers 45.

The recycled part of the cooled fumes, after passing through separating device 18 and fan 19, reenters forming section 22 where, by mixing with the gases from fiber pro- -duction device 11, the recycled fumes cool these gases and the fibers.

It is also contemplated to directly cool the current 12 of fibers and gas by projecting water on it, and dis-charging this water outside of forming section 22 to thereby remove the heat brought in by the materials to be fiberized and the attenuating or guiding fluids. The projection of water on the current thus takes place in the zone where the contact surfaces cannot be very large since the available space is small, but where the temperature differential between the fluid to be cooled and the cooling fluid is large.

~,,,: - ' ~06~64~i For example in the embodiment represented in Figure 1, atomizers 49, placed between fiber production device 11 and binder devices 13, project a cloud of fine droplets of water against the attenuated fibers and gases of the current to be cooled.

The droplets reach the current of gas and fibers in a zone where this current is at a high temperature, which may reach 600 C., and are immediately vaporized, thereby effect-ing cooling at high efficiency. The large quantities of heat--on the order of 650 to 700 Kcal per kg of water--nec-essary to vaporize the droplets are taken from the current of fibers and gas, which consequently undergoes a very rapid cooling. This reduces the temperature of the current, at the level of binder devices 13, to a value on the order of 100 to 120 C. The vapor produced is evacuated with the fumes, through fiber blanket 23, into chamber 16 and washing chamber 17, where in contact with the curtain of water sprays emitted by atomizers 45, the vapor condenses, transferring its latent heat of vaporization to the cooling water coming from atomizers 45. This heat is thus discharged from the system along with the water from the atomizers -45. :

The placement of the spray devices 49 for projecting the cooling water against current 12, between fiber produc- :
tion device 11 and binder nozzles 13, is preferred since in operation this arrangement has certain special advantages:

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First of all, it is in this zone that the tempera-ture differential between the current to be cooled and the water is the greatest and where the heat transfer is con-sequently the highest.

The binder is then sprayed on a current of cooled fibers and gases, at a temperature that is sufficiently low (100 to 120 C.) so that breaking down of the binder -due to volatilization of constituents thereof is very limited or non-existent.

As a result, there is an increase in the binder efficiency of the order of 5%, and a consequent reduction in the pollution from the fumes.

The cooling water is discharged externally of the installation by orifices 24 and 25 placed at low points in chambers 16 and 17 and in water separating unit 18, into device 51, in which the solid particles in suspension in the water, notably fibers, are separated.

Device 51 may be either a filter, with meshes, of a known rotating or vibrating type, or a decanter, or a centrifuge, also of known type.

The water, free of suspended solid particles, is collected in a tank 52 and the water is then directed, by gravity or by means of a pump 53, into a cooling station 54. Upon leaving this station, the cooled water may be discharged outside or reused in the system.

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As shown in Figure 1, station 54 may include a cooling tower 106, of known type, in which water is cooled by contact with air. The cooling water is circulated through the spray cooling tower by means of a pump 107. The water from tank 52 is brought into indirect heat exchange relation to the cooled water of the tower 54 by means of the heat exchanger indicated at 105, from which the cooled water may be returned to the tank 52. Make-up water may be intro-duced as by the water supply connection indicated at 111.

It is preferred to cool the washing water by in-direct heat exchange with the cooling water (or other cooling fluid) circulating through the cooling tower 106, because this completely avoids polluting the air with any remaining volatile pollutants in the wash water, although the content of such remaining pollutants in many installations is so very low (for instance, less than 5% of the quantity discharged by the gas offtake of a nonrecycled installation such as shown in Figure 1) that it may be practicable to directly cool the wash water in the spray cooling tower 106.

An advantage provided by the invention, is that it is contemplated that no water in liquid state be discharged outside of the installation, so as not to contaminate the environment even by the small content of pollutants that the water still contains.

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This implies that the water introduced through nozzles 49 or 50 and the washing water circulate in a closed circuit within the installation.

In installations represented by Figure 1, the closed circuit of the cooling and washing water is the following:

--The water leaving cooling station 54 is sent via pump 55 to the cooling spray devices 49 situated in chamber 22, and also to the vapor condensation devices and fume washing devices placed in chamber 17, which include the atomizers 45 as shown in Figure 1.

--The washing water and the condensed vapor, charged with pollutants, fibers, and binder components, flow through orifices 24 and 25 placed at low points in washing chamber 17 and water separator 18, into a collector 26 which leads them towards filtration device 51; this separates solid wastes 56 in suspension/ fibers, and insoluble binder com-ponents from the washing water.

These wastes are collected on a conveyor 57.

Since the filtered washing water only contains dissolved binder components and pollutants, it is sent by gravity .
or via pump 53 towards cooling station 54.

The applicants have observed that when the washing water circulates in a closed circuit, it is necessary to maintain the concentration of the materials dissolved or 106964~-suspended in the filtered water below a certain value, this being on the order of 3 to 4%--computed in unit of mass of dry materials per unit of mass of water. Above this value some of the materials dissolved or suspended in the washing water (essentially microfibers or microparticles of binder not captured by filtration device 51, and soluble binder components) are deposited on different parts of the installation. The binder is polymerized, forming viscous or solid layers which progressively obstruct the washing water ejection orifices 45, 49 and 50 and also the orifices in collection belt 15 for the passage of fumes 29. As a result, there is a reduction in the quantity of fumes evac-uated from the hood and in the cooling of these fumes, soon leading to shutdown of the installation.

In order to maintain the concentration of materials carried in the water below the value which will obstruct spraying or fume evacuation, it is necessary to extract large quantities of materials from the washing water. In operation, a large proportion, on the order of 20 to 30%
of the binder sprayed on the fibers by nozzles 13 ends up in the washing water, in the manner already described.
For large plants, this makes it unavoidable that 3,000 to 5,000 kilograms of binder per day (counted in dry material) will be introduced into the closed circuit for circulation of the washing water, and it is necessary to extract from the water quantities of binder identical to those introduced in order to maintain the concentration at an equilibrium value.

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According to the present invention this is done as follows:

A small portion--on the order of 1 to 5%--of the flow of washing water charged with dissolved binder circulat-ing in the circuit, is heated so as to insolubilize thebinder, followed by separating the binder from the water by any appropriate means of separation such as filtration, flocculation, centrifuging...

~' , '' In operation, the applicants have observed that if the water used for cooling and washing of the fumes--and thus, after filtration, containing the binder or dissolved binder components--is maintained at a given temperature for a given period of time, a proportion of the dissolved binder increasing with the temperature and the time would be transformed into insoluble particles and would subseq-uently be found in suspension in the water and could then be easily separated from the water.

The proportion of dissolved material--insolubilized by the treatment--characterizes the efficiency of the treatment.

The treatment temperature has a very important influence on the efficiency. For example, it has been found that for a water containing 1% dissolved binder component, the treatment efficiency is:

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40% if the water is maintained at 40C. for eight days;
40% if the water is maintained at 70C. for three days;
40% if the water is maintained at 160C. for three minutes;
60% if the water is maintained at 180C. for three minutes;
95~ if the water is maintained at 240C. for three minutes.

Figure 2 shows the evolution of the treatment efficiency as a function of the temperature and of the treat-ment time.

In large capacity plants manufacturing panels of agglomerated fibers, since the quantities of water to be treated may reach 50 m3/h, in order to avoid the installa-tion of treatment plants of considerable dimensions, it is necessary to determine the shortest treatment times and thus to work at high temperatures, greater than 100 C.
This means carrying out the treatment in a pressurized chamber, at a temperature maintained at approximately 5 C. below the boiling temperature of water at the pressure of the chamber, so that the water remains in the liquid phase through-out the duration of treatment. This solution also has the advantage o~ requiring only a small energy expenditure which, with respect to the wastes, only corresponds to the increase in heat imparted to the water in order to raise its tempera-ture.

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106964~i One of the disadvantages ordinarily encountered when heating in a chamber water containing the binder or dissolved binder components, even in a weak concentration, is that an insolubilized binder deposit forms on the walls of the chamber which very quickly becomes thick enough to obstruct the evacuation orifices of the chamber, or the chamber itself.

The applicants have observed that if the heat necessary for treatment is released in the water mass to be treated and the wall of the chamber is maintained throughout the treatment at a temperature less than that of the water mass treated, there is no formation of deposit on the wall, the insolubilized binder remaining in suspension in the water.
This leads to heating the water, either by mixing with hot fluids such as steam that has preferably been superheated, or with immersed burner combustion gases, or by means localizing the energy in the midst of the water mass such as an electric arc.

A wide range of operating conditions is possible, for example 6 to 40 bars for the absolute pressures, from 150 to 240 C. for the temperatures, and from 3 to 10 minutes for the treatment duration.

The following conditions are the result of a satis-factory compromise between the energy cost and the equipment maintenance cost:
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--temperature: 2Q0 C.
--pressure : 16 bars absolute --duration : 5 minutes --efficiency : from 70 to 80%.

This method of treatment may be applied to a dis-continuous operation set-up or to a continuous operation set-up.

Figure 3 shows a discontinuous operation set-up for the application of this treatment process. The water to be treated is introduced to chamber 68 through motorized valve 67. The quantity of water introduced, or the charge, represents 70 to 80~ of the capacity of this chamber. The heating fluid or vapor--preferably superheated--then penetrates the chamber through injector 69, whose outlet orifice is immersed. The quantity of vapor is regulated by motorized valve 70, controlled by regulator 71.

The treatment cycle takes place as follows.
Chamber 68 contains a water charge to be treated which is initially under atmospheric pressure.
The treatment pressure desired, for example 16 bars absolute, is recorded on regulator 71.

Valve 70 opens and the vapor flows through injector 69, mixes with the water to be treated, and upon condensing transmits all of its latent and sensible heat to the water. -~
The temperature and the pressure in chamber 68 rise until reaching approximately 200 C. and 16 bars absolute.

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The introduction of vapor is then terminated.
Injector 69 has been adjusted so that this temperature and pressure rise is rapid, occurring in less than one minute.
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The water is maintained at 200 C. and 16 bars absolute for two to four minutes.

At the end of this period of time, a pump 72 is put in operation in order to deliver through jacket 74 a , new charge of water to be treated, into a vat 73. As it passes through the jacket the water to be treated--which is at a temperature of approximately 40 C. at the entrance--initiates the cooling of the treated water contained in chamber 68. The dimension of jacket 74 is adjusted so that the water to be treated reaches vat 73 at a temperature of approximately 80 C.

A supplementary cooling fluid circulates in the jacket 75 and completes the cooling of the treated water contained in chamber 68. This cooling is considered to be completed when the temperature of the treated water drops below 100 C., and preferably 40 to 50 C. At this moment, a motorized valve 76 is progressively opened in order to decompress chamber 68.

The treated water flows towards a filtration station 51, or a flocculation, decantation, or centrifuging device, which separates the binder insolubilized by the treatment from the treated water.

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The filtered water flows into vat 52 and the extract-ed wastes 56 are delivered to a conveyor 57.

When chamber 68 is empty, valve 76 is closed and valve 67 is opened, thus permitting the preheated charge of water in vat 73 to flow by means of gravity into chamber 68. An exhaust 67a completes the installation.

A new cycle may be started again.

Figure 4 shows a continuous operation set-up for the application of the treatment process.

A pump 77, under the treatment pressure, sends the water to be treated to a mixer 78 in which an injector 79 is arranged, through which the heating fluid consisting of steam is introduced. This steam mixes with the water to be treated and, upon condensing, transmits its total heat to this water. The steam flow is regulated by motorized valve 80 controlled by regulator 81, in order to maintain the desired treatment temperature at the outlet of mixer 78. Subsequent to leaving mixer 78 in which it has remained for 10 seconds, the water to be treated passes through a reactor 82, where insolubilization of the binder takes place--the dimensions of which are adjusted so that the retention time of the water to be treated corresponds to the duration of treatment, for instance 2 to 4 minutes.

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1o6g64~ . ' Subsequent to leaving the reactor, the water is cooled in an exchanger 83, to a temperature less than 100 C., and preferably from 40 to 50 C. Some of this cooling is provided by the water to be treated, which is thus preheated in coil 84 from approximately 40 C. to approximately 80 C.

The rest of the cooling is provided by a cooling ~:
fluid circulating in coil 85.

Subsequent to leaving exchanger 83, the treated and cooled water is decompressed to atmospheric pressure .
through a pressure-reducing valve 86 which, controlled by a regulator 87, maintains the treatment pressure in the installation.

The decompressed water flows towards a filtration device 51, or a flocculation-decantation or centrifuging device, which separates the binder insolubilized by the treatment from the treated water. The filtered water flows towards vat 52 and the wastes 56--residues of the treatment- :
-are delivered to a conveyor 57.

The set-up shown in Figure 4, of the continuous operation type, permits a more flexible and less costly treatment than that shown in Figure 3.

-25- ~ -. d~ , ., , ~, . .
.

Claims (9)

The properties of the invention in which an exclu-sive right or privilege is claimed are defined as follows:

1. Apparatus for separating heat hardenable resin constituents from an aqueous solution thereof, comprising pressurized treatment equipment for heating the solution to a temperature sufficient to insolubilize said constituents and for maintaining the solution heated and under super-atmospheric pressure for a time sufficient to effect such insolubilization, said treatment equipment comprising a batch treatment vessel having means for heating the interior of a batch of the solution therein and having means for cool-ing the walls of the vessel during said heating, said pres-surized treating equipment having an inlet for receiving pressurized solution to be treated and having an outlet for discharge of treated solution at atmospheric pressure, a supply source for solution to be treated, means connecting the supply source with said inlet including means for preheating the solution being supplied, and means receiving the treated solution discharged from said outlet and for separating the insolubilized constituents from the heat treated solution at atmospheric pressure.

2. Apparatus as defined in Claim 1 in which the cooling means comprises a jacket for the vessel and means for circulating solution to be treated through said jacket prior to being introduced into the treatment vessel.

3. Apparatus as defined in Claim 2 in which the cooling jacket through which the solution supply circulates encloses only a part of the treatment vessel, and a second cooling jacket enclosing another part of the treatment vessel, and separating coolant circulation means associated with said second jacket.

4. A method for separating water soluble but heat insolubilizable resin constituents from an aqueous solution thereof, which method comprises insolubilizing said constitu-ents by heating the solution to a temperature between about 150°C. and about 240°C., at an absolute pressure of from about 6 to about 40 bars, and thereafter separating the insolu-bilized constituents from the water.

5. A method as defined in Claim 4 in which the solution to be heated is preheated by bringing it into heat exchange relation with the heated water undergoing the in-solubilizing treatment.

6. A method as defined in Claim 5 in which the solution to be heated is brought into heat exchange rela-tion with the heated water before separation of the insolu-bilized constituents, and in which the insolubilized constitu-ents are separated after such heat exchange.

7. A method as defined in Claim 4 in which the treatments are effected batchwise.

8. A method as defined in Claim 4 in which the treatments are effected continuously.

9. A method as defined in Claim 4 in which the solution to be heated is preheated by bringing it into heat exchange relation with the heated water after insolubilizing of said constituents.