LU84208A1 - METHOD AND APPARATUS FOR COOLING A HOT CURRENT OF PARTICLE-LOADED PROCESS - Google Patents

Description

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The present invention relates generally to the cooling of process streams loaded with particles and more specifically relates to an integrated process and element for cooling hot streams of process loaded with particles by separating the feeds therefrom. particles by filtration on canvas.

In many industrial processes, products or by-products are formed in the form of suspended particles, that is, in the form of a particulate solid component entrained in a component consisting of 'a hot gas stream. For example, furnace carbon blacks are formed by thermal decomposition and / or partial combustion of hydrocarbon feedstocks and are normally obtained initially as an aerosol or a suspension of particulate carbon black in hot smoke gases formed as by-products. The stream of the carbon black forming process is quenched in the carbon black forming reactor in order to complete this forming reaction, after which it is further cooled and then filtered canvas to collect the carbon black formed. Among some other examples of industrial processes in which a hot process stream charged with particles is cooled and then subjected to canvas filtration, processes for which the present invention can be effectively adopted, are: the treatment of fumes from coal-fired power plants before separating the particulate charge by filtration, cooling of calcination streams from a dry process cement, cooling of streams containing dust t i.

3 of calcined rocks or ores and the like.

More specifically, the canvas filtration methods adopted in the industry consist in passing a gaseous stream charged with particles 5 through one or more filtration elements made up of a porous fabric or fabric, these elements having a porosity or a selected transmissibility which, at the outset, is sufficient to allow the gaseous component of the process stream to pass, however it is insufficient to allow the passage of the particulate component. Consequently, the particulate component is separated from the gaseous component and is deposited on the upstream side or the collector side of the fabric filtration elements.

Elements are usually provided for the purpose of more easily removing the particulate charge from the filter elements, for example, periodic re-pressurization or reversal of the gas stream therethrough, mechanical agitation or vibration, and analogues. The particulate charge thus separated is generally sent to a collecting hopper from where it is periodically removed to "be conditioned and / or to undergo additional treatment which may be desirable or necessary to obtain a finished product in particles. In industrial processes for the production of furnace carbon black, the so-called “fluffy” carbon black collected from the canvas filtration device can be subjected to additional treatments such as: wet rolling 3 dry route 3 densification; calcination 3 surface oxidation with air, ozone or mineral acids, grinding such as ankle grinding, hammer grinding or energy milling 'a fluid; treatment with agents

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4 surfactants, oils or oil emulsions and the like ”

The fabrics used for the manufacture of filter elements are usually made of woven or non-woven textile fibers such as glass, cotton, wool, polyamide, polyester, polytetrafluoroethylene fibers or their blends. These materials are shaped or sewn into the geometric shapes required for the particular canvas filtration device used.

A filtration device usually used is what is called a "bag filter", the fabric filtration elements of which have an elongated tubular shape. In other known canvas filtration devices, canvas filtration elements are used in the form of envelopes, sheets, bolts or discs. In some other known canvas filtration devices, canvas filtration elements are used which have essentially no shape, the canvas filtration material being simply used in the form of stuffing or a charge. for a cartridge element through which the process stream laden with particles passes.

However, regardless of the particular fabric filtration device used, it is essential that the process stream charged with particles conducted therein has a temperature which is not so high as to have a detrimental effect on the canvas filtration elements of this device. Likewise, it is also important that the temperature of the process stream passed through this filtration device is high enough to maintain the atmosphere prevailing in the latter at a temperature above the dew point of the gaseous component of the filtration stream. process, thus attenuating the condensation of condensable products outside this current. If one fails to comply with the first criterion -temperature, one shortens enten-5 of the excessively the lifetime of the fabric filter element. If the second temperature criterion is not met, an altered and / or impregnated particle product is collected, obstructing the canvas filtration elements. In the case of furnace carbon black manufacturing operations, if the wet carbon black is collected in the canvas filtering device, not only has the effect of the efficiency of: step during which the carbon black is collected, but also on the efficiency and the quality of the downstream finishing operations, for example, pelletizing, densification or subsequent chemical treatment of the carbon black collected, as well as on the quality and uniformity of the final carbon black.

Although it is possible to cool a hot process stream charged with particles by meeting the above-mentioned temperature criteria by means of indirect heat exchangers, the efficient and economical operation of these heat exchangers pose a problem. Normally, the temperatures that a particle-laden process stream must reach in order to be treated by canvas filtration are between about 149 ° C and about 30,371 ° C. Indirect heat exchange is usually an economically justifiable process for extracting heat only when the temperature drop to be achieved is relatively large, for example, on the order of 300 ° C or more, as well as, when the hot process stream 6 to be cooled is at a temperature substantially higher than about 5'38 ° C. Thus, for example, to cool a process stream charged with particles from a temperature of 538 ° C to S about 200 ° C by an indirect heat exchange technique, generally large and expensive equipment is required. the economic factors of which are usually not justified, even assuming that there is total compensation for the heat energy extracted 10 In addition, indirect heat exchange equipment is usually designed for operations taking place under relatively static conditions and, therefore, this equipment is usually ill-suited to perform reasonably accurate control in response to fluctuating operating conditions. Therefore, given the above deficiencies, it is common practice in operations taking place in chemical plants, first extracting and recovering hot process current and by indirect heat exchange, the largest possible amount of heat that can be considered economically, and then further cooling the process stream to temperatures suitable for canvas filtration by atomizing water to it in liquid form.

This abrupt cooling of the process stream to temperatures suitable for filtration on canvas is normally accomplished by atomizing water in the liquid state under pressure or with two fluids in the process stream at a certain point located relatively far upstream of the stream. 'entry of the cooled current into the filtering device on canvas. In contrast to spraying, atomization is carried out to give tiny droplets which, of course, evaporate faster than the relatively larger droplets obtainable by conventional techniques. spray. The elongated pipe interposed between the atomization point of the cooling water 5 in the process stream and the filtration device is provided so that the atomized liquid water has sufficient time to evaporate completely before entering process current cooled in the canvas filtration device. Of course, it is obvious that if the liquid water does not evaporate completely during the process, it can result in difficulties similar to those which have already been mentioned above with regard to the condensation of the gaseous component of the process stream inside the canvas filtration device,

The underlying reason for providing a relatively long residence time after atomization of the liquid cooling water into the process stream is that, to the knowledge of the Applicant, neither the techniques of atomization with two fluids, nor the pressure atomization techniques which are usually used in industrial operations, do not lend themselves to the formation of droplets of a tiny size under a range of operating conditions sufficiently wide to ensure their Uniform, rapid and complete evaporation in the process stream. During atomization under pressure, water is expelled through a nozzle having a restricted orifice, while the efficiency at which the injected water is fractionated into droplets, and the average size of the latter largely depend on the dimensions of the orifice of the atomizing nozzle and on the pressure drop generated across this orifice. turn, the flow of water through an orifice having given dimensions is obviously a function of the pressure drop î the higher the pressure drop, the greater the flow rate * Minor variations made in one or 1 * Another 5 of the above parameters have a very pronounced effect on the uniformity and the size of the droplets formed. For most industrial chemical installations, the size of the orifice of a given pressure spray nozzle can be considered as an invariant parameter. However, this is not normally the case with regard to flow rates and pressure drops. In operations in industrial plants, the pressure and flow in the water pipelines, as well as the temperature and flow of the process stream to be cooled, are normally subject to wide variations. If the temperature and / or flow rate of the hot process stream changes, for example, as a result of changes in reactor conditions to modify the properties of the product, it is usually also necessary to modify the flow rate of the product. cold cooling water atomized in this stream in order to reach the temperature envisaged before the filtration treatment on canvas. Consequently, large variations can occur incidentally or intentionally in the pressure of the water supplied to the atomization nozzles and, during the implementation of the process, it can result from periods during which the nozzles of atomization under pressure do not work and cannot work until pressure losses and flow rates for which. .they were . designed. Under these conditions, the droplets formed by pressure atomization techniques can be much larger and their uniformity can be reduced, which requires much longer residence times in the process stream subjected to sudden cooling. to ensure complete evaporation of the water. In the two fluid atomization nozzles 5, a propellant gas is used to split a stream of water into tiny droplets inside the nozzles, de. same as to project these droplets (entrained in this gas) into the process gas stream. In order to ensure efficient operation of these nozzles with two fluids, relatively high volumetric flow rates are generally adopted for the propellant gas, the latter being normally not available in itself at the place of installation and, 1-5 in any case, it constitutes, in the process stream, an additional gaseous charge which, ultimately, must be treated in the canvas filtration device located downstream.

In order to maximize the drying time, in the process stream, of abrupt cooling water atomized under pressure or by two fluids, as has been mentioned, the usual method has been to intercalate a large volume conduit or a so-called "riser" 25 between the atomization point of the quenching water in the process stream and the canvas filtration device. Under these conditions in which the droplet dimensions of the atomized cooling water are relatively large, the rate of evaporation of the latter can be considerably reduced in the process stream flowing through the riser.

In furnace carbon black manufacturing operations, these reduced evaporation rates may increase the risk of impregnation and agglomeration of the particulate component of the process stream inside the column rising, while thus collecting a carbon black comprising significant.quantities of large hard agglomerates. In addition, since the process current can very often be highly corrosive, the riser pipe must also very often be made of expensive corrosion-resistant alloys. However, up to now, the need to avoid the presence of liquids inside the canvas filtration device has outweighed the considerable economic deficits imposed by the construction and implementation of a column. rising of a large volume of a corrosion-resistant alloy 15 installed upstream, as well as the risk of encountering the aforementioned phenomenon of the formation of agglomerates of the particle component in this riser before the present invention, industry reluctantly accepted these shortcomings in order to ensure complete evaporation of the quenching water introduced into the pro stream. sold under a wide range of operating conditions. According to the present invention, the abovementioned difficulties are completely eliminated or, at least, substantially overcome.

A main object of the invention is to provide a new process for the cooling of a hot gas stream charged with particles.

Another object of the invention is to provide a new apparatus for cooling a hot gas stream charged with particles.

Another object of the present invention is to provide an improved integrated process for separating the particle component from a hot process stream charged with particles.

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Another object of the present invention is to provide an integrated and improved system for separating the particulate component from a hot process stream charged with particles. Yet another object of the present invention is to provide a method and a system integrated and improved in order to separate a furnace carbon black from a hot process stream containing this type of carbon black * * 10 Other objects and advantages of the present invention will be, in part, obvious and will appear, in part also, on reading the description below *

In accordance with the present invention, a hot particle-laden gas stream is passed through a venturi-shaped conduit having dimensions and geometry designed to accelerate the process stream to at least Mach 0.25. In the constriction of the venturi-shaped conduit, water in the liquid state is practically injected transversely into this gas stream via a number of unrestricted orifices. Due to the energetic flow of the process stream at the points of introduction of liquid water into the latter, the various streams of water are rapidly fragmented, disintegrated and sheared into uniform droplets of relatively small size. , which makes it possible to extract the heat from the gas stream by rapid evaporation of the water droplets thus formed. The process current or the gas thus cooled is conducted through a fabric filtration device so as to separate the particle component from the gas component.

In the accompanying drawings: Figure 12 is a block diagram the solid lines of which illustrate a cooling apparatus according to the invention integrated in a specific line for the production of carbon black oven, while the broken lines represent a conventional cooling device of the prior art on a relatively comparable scale; Figure 2 is a schematic longitudinal section of the embodiment of the cooling apparatus * 10 of the invention as illustrated in Figure 1; Figure 3 is an enlarged schematic longitudinal section of part of the cooling apparatus illustrated in Figure 2.

15 In FIG. 1, a conventional line for the production of oven carbon black is shown, the main elements of which are designated by the reference numerals 1, 9 * 14 and 15 · A hydrocarbon feedstock, a fuel and a gaseous oxidizing agent 20 (usually air) are introduced into a reactor 1 for manufacturing carbon black. In this reactor, the mixture obtained is ignited and the reaction mixture during combustion passes into the reaction chamber 5 with refractory interior lining 25 where conditions of carbon formation are maintained. Usually, the temperature in this reaction chamber 5 is maintained between about 1,315 ° C and about 1,760 ° C, the exact temperature depending mainly on the desired properties of the carbon black. Control of the temperature inside this reaction chamber 5 is usually ensured by calculating appropriate proportions for the oxidizing agent, the fuel and the charge which are conveyed to the reactor 1.

The completion of the carbon-13 reaction is initiated by so-called "primary coarse cooling" during which water is sprayed, through a nozzle 6, into the reaction mixture as this last advance through the downstream part of the reaction chamber 5 · The rate at which the quenching cooling water is sprayed into the reaction mixture is calculated appropriately so as to rapidly lower the temperature of the process stream to about '10 1.204 ° C or less. Since at this stage of the process the thermal energy contained in the reaction mixture is relatively high, the rapid evaporation of the water from the primary abrupt cooling is ensured by inherence and, normally, the operation of the the hard cooling nozzle 6 is not critical.

The process stream thus obtained and comprising carbon black suspended in flue gases is then led from reactor 1 to an indirect heat exchanger 9 in which this process stream is further cooled, usually to a temperature between about 426 and 6480C. The indirect heat exchanger 9 is usually cooled by the oxidizing agent of the combustion used in the carbon black formation process in order to preheat this agent before its introduction into the reactor 1, thus making it possible to recover large amounts of heat which, under other conditions, would be lost, while improving the thermal efficiency of the whole process.

Carbon black is usually separated from the process stream in a fabric filtration device 15 such as a bag filter, the process stream passing through porous fabric filtration elements so as to retain the carbon black charge on the upstream side of these elements, while allowing the process gases to pass through. The carbon black separated and collected 5 in this canvas filtration device 15 is then conditioned or treated in another way, as described above.

In order to preserve the fabric filtration elements of the device 15> it is first of all necessary to further cool the process stream which is still relatively hot and which leaves the indirect heat exchanger 9 * usually at a temperature between approximately 149 ° C and approximately 371 ° C. the exact temperature contemplated is largely determined by the following two considerations: the dew point of the gaseous component of the process stream and the thermal stability of the particular fabric filtration elements used in the device 15 · 20 According to the conventional method, this additional cooling or this "secondary cooling" is carried out of the process current for the production of carbon black from the oven before its filtration on canvas by electrifying the process current through 25 partially cooled from the indirect heat exchanger 9 through a vertical, elongated and large volume duct or a column aunt 149 while atomizing water in the upstream end of this conduit or column. For comparison, this riser 14 may specifically have, for example, a length of about 30.48 m, a diameter of about 1.524 m and is usually made of an expensive corrosion-resistant alloy. At the upstream end of this riser 14, there are arranged one or more nozzles 16 for atomization 15 under pressure, or with two fluids by which abrupt cooling water is atomized in the process stream at one sufficient speed to cool the latter to the chosen temperature. # For the most part, the long part of the riser 14 which is located downstream of the nozzles 16 is provided in order to ensure a sufficient residence time of the Process stream subjected to sudden cooling in order to completely evaporate the atomized cooling water • • 10 before the introduction of this process stream into the canvas filter device 15 # For whatever reason, if the atomized water droplets should be relatively large, for example, on the order of about 15,300 x 10 "^ m or more, their rate of evaporation in the process stream will be relatively low, thereby creating a large laugh that of a significant contact between the component constituted by carbon black in particles in suspension with the liquid water during the circulation of the process current through the riser 14 # As mentioned previously , if this impregnation of the carbon black particles occurs, the particles thus impregnated can then collide with each other forming large agglomerates #

Likewise, the particles impregnated with carbon black can come into contact with the walls of the riser 14, thus causing a concretion and solidification of the carbon black on these pa-kings.

According to the present invention and with reference to the solid lines in FIG. 1, as well as to FIGS. 2 and 3 in general (in all these figures, the same reference numerals 35 denote the same structures), the current of relatively hot process 16 and charged with particles leaving the indirect heat exchanger 9 is sent through a venturi-shaped duct 20 whose geometry and shape are adapted to accelerate this current to at least about Mach 0 , 25 in the constriction 24 of this conduit # By 1 * expression "Mach number", we mean the numerical quotient, without dimension of the real speed of the process current, divided by the local speed of sound inside of this stream # 10 Therefore, the Mach number of the process stream depends on both temperature and composition and it can be easily determined for any given set of conditions taking full account of temperature and composition 15 of the particular process current in question # The size and geometry of the venturi-shaped duct 20 will advantageously be chosen so as to "accelerate the process current to a Mach number of at least 0.4 inside l throttling 24.

The venturi-shaped conduit 20 comprises an upstream portion 22 of relatively rapid convergence, a throttle 24 and an downstream portion 26 of a relatively gentle divergence. In the particular embodiment of the illustrated invention. 25 in the accompanying drawings, in the middle and along the longitudinal central line of the constriction 24, is situated a supply line 25 ending in an end cap 27 # The supply line 25 is held in its position central by means of a spacer 28 extending from the wall of the converging part 22 of the venturi-shaped duct 20 # The end cap 27 has several unrestricted openings ^ which are oriented radially with respect to the longitudinal central line of the pipe 35 forms a venturi 20 and through which from 17 the cooling water in the liquid state is practically introduced transversely into the process stream flowing through the constriction 24 · The adjustment of the flow of the abrupt cooling water 5 through the orifices 29 can be ensured by the combination of a water supply valve 50 and an adjustment device 51 · This re-adjustment device 51 receives, from a thermocoupl e of output TQ, information relating to the temperature of the process current * 10, then it integrates these data with respect to a preset or given or fixed temperature and it reacts by adjusting the water supply valve 50 in the manner required to reach the set temperature of the abruptly cooled process stream. Since the present invention is mainly dependent on the kinetic energy of the accelerated process stream to fractionate the water. sudden cooling into tiny droplets and to disperse the latter in this stream, the diameter (s) of the unrestricted orifices 29 and the pressure (or flow) at which the cooling water passes through these orifices, are liable to undergo d There are large variations and they are not normally critical of the formation of tiny, uniform droplets which can evaporate quickly within the process stream. This advantageous characteristic of the present invention differs clearly from the critical parameters normally occurring in the operation of atomization nozzles under pressure or with two fluids according to the prior art. The number and the diameter or diameters of the orifices 29 are advantageously chosen so that, in the range envisaged for the abrupt cooling water flows 35 involved in the particular process envisaged, sufficient pressure is created at each of these orifices to project the resulting sudden cooling water stream into the process stream at least a short distance from the surface of the cap 5 at end 27 before the sudden cooling water stream disintegrates and significant fragmentation. The included angle of divergence of the diverging portion 26 of the venturi-shaped conduit 20 is generally not critical. However, it is preferable that this angle of divergence is in the range of from about 6 to about 14 ° and, according to a more preferred feature, in the range of from about 7 to about 10 °.

If these preferred limits are respected, this divergent part 26 will generally act as a diffuser, thus minimizing the pressure drop created across the conduit 20 for a given acceleration of the process current, while extending the distance 20 on which this current retains a high speed.

In another preferred embodiment of the invention, at least the divergent part 26 of the venturi-shaped duct 20 is thermally insulated, for example, by means of a heat-insulating coating 30. This insulation 30 serves to attenuate the forces of entrainment of thermal deposition of the hot process stream, forces which, under other conditions, could tend to cause at least a certain deposition of the particle component of this stream on the surfaces 30 located immediately downstream of the throttling 24.

In another preferred embodiment of the invention, the upstream end of the converging part 22 of the venturi-shaped duct 20 is fed by a short length of a duct 18 including 19 carrying a rectifying element flow 19. This element 19 installed immediately before the venturi-shaped duct 20 has the effect of minimizing turbulence and eddies inside the process stream as the latter becomes close to this duct 20, thus ensuring efficient acceleration in the latter * "In view of the extremely rapid disintegration and evaporation of the abrupt cooling water introduced into the process stream according to the present invention, both the conduit" form of venturi 20 that the duct 31 which establishes a communication between the downstream end of this duct 20 and the inlet of the filtration device on the fabric 15, can be much more compact (on an equal operating scale) than the Secondary cooling systems of the riser type according to the prior art, which represents an important advantage offered by the implementation of the present invention since, as indicated above, secondary cooling systems of the column Rising in the prior art usually involve apparatuses having relatively very large lengths and volumes. By adopting the method and apparatus of the present invention, for example, a current of carbon furnace black manufacturing process of the same type as that contemplated for establishing the dimensions of the riser 14 which has been mentioned above with respect to the prior art, can be effectively cooled to a contemplated temperature in a venturi-shaped conduit according to the present invention having inlet and outlet diameters of about 0.8128 m, a constriction with a diameter of about 0.4004 m and a total length of between about 3 * 6576 m and about 4.572 m. In addition, the length or volume of the duct 31 is determined practically only by the need to establish a fluid-tight communication for the process current cooled in the canvas filtration device 15 · In addition, the apparatus of the The invention need not necessarily be oriented vertically as is the case in the risers of the prior art but, on the contrary, it can be given any suitable orientation in consideration of the space available and the efficient arrangement. of the installation.

Furthermore, the present invention is much less sensitive to temperature variations at the inlet of the process stream than in the prior art riser whereby the quench water is subjected to pressurized atomization. By adopting the latter process of the prior art, for example, a decrease of about 38 ° C in the inlet temperature of the process stream supplied to the riser 14 has the effect of reducing the flow rate by about 20% of water to be atomized under pressure in the process stream 25 to reach the envisaged temperature. However, if the water pressure is reduced by 20% in order to regulate the flow rate of the descending water stream, the average size of the droplets obtained by pressure atomization is markedly increased, as is the residence time required to evaporate these larger droplets and the volume of the downstream duct necessary to ensure this increased residence time. However, by adopting the method and apparatus of the present invention, a similar reduction in the process stream inlet temperature and a similar reduction in the sudden cooling water flow rate only results in a relatively minor increase in the size of the droplets and also a relatively minor increase in the residence time required to ensure complete evaporation of these droplets. Therefore, unlike the prior art riser systems, the increase in length or volume of the downstream conduit is small, if any, in the apparatus of the present invention to establish an adequate residence time in order to ensure complete evaporation of the quenching cooling water and response to temperature and flow fluctuations occurring in the process stream and the quenching cooling water stream. Likewise, although the shearing and disintegration of the quenching cooling water introduced into the process stream as a result of the practice of the present invention can be considered as a type of two-fluid atomization, the propellant for the atomization of the abrupt cooling water does not constitute an external diluent, the process current and the propellant gas constituting a single and same entity. Consequently, the method and the system of the present invention make it possible to avoid an additional dilution of the process current and it is not necessary to increase the gas treatment capacity of the canvas filtration device 15 ·.

Although, for purposes of illustration, the present invention has been described in detail above only with reference to a manufacturing line. of furnace carbon black and only in terms of final separation of the particulate component by filtration through canvas, it is evident that the present invention can be applied advantageously to many other chemical treatment plants in which it is necessary to cool a hot process gas stream containing suspended particulate solids.

Also, although the present invention has been described above with reference to some of its preferred embodiments, it should be noted. that the above description is given by way of illustration only and does not limit the invention in any way. For example, although the specific apparatus illustrated and described comprises an end cap 27 installed at the center of the throttle 24 of the venturi-shaped conduit 20, this cap 27 acting as a final element for the introduction of the Sudden cooling water in the process stream, it is obvious that other functional equivalents of this system can be considered. For example, the element intended to introduce the sudden cooling water can also be produced in the form of several radial orifices penetrating into the peripheral wall and situated on the periphery of the constriction 24 of the venturi-shaped duct 20. These orifices can then be surrounded by a common collector equipped with a water supply pipe.

Of course, those skilled in the art will recognize many other suitable equivalent embodiments of the apparatus and method of the invention and it is understood that all of these changes, variations, modifications and the like are within the scope and essential spirit of the invention as defined in the claims below.

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Claims (28)

1 · A method of cooling a hot gas stream charged with particles before collecting the particle component thereof, this process consisting in atomizing water in the liquid state in this stream in a quantity calculated so as to extract the heat by evaporation of the liquid water which is thus atomized therein, this current being cooled to a temperature above its dew point, characterized in 10, this hot gas stream charged with particles is passed through a relatively compact conduit (20) in the form of a venturi comprising a converging upstream part (22), a diverging downstream part (26) and a throttle (24) between these two parts; 15 'this gas stream being accelerated to a Mach number of at least about 0.25 in this throttle (24) while, in this throttle, the cooling water must be introduced, practically transversely into the gas stream atomized in the form of several streams, 2, A method according to claim 1, characterized in that, in the throttle (24), the hot gas stream charged with particles is accelerated to a Mach number of at least about 0.4 · 25 3 * Process according to claim 1, characterized in that the liquid water is introduced practically transversely and towards the outside into the gas stream from a central element (27) installed in the constriction, this element (27) comprising 30 or more unrestricted orifices (29) oriented radially · '4 · A method according to claim 3j characterized in that the flow of water introduced ----- from this element (27) is sufficient to project each of the streams of liquid water in the neck— "" Rant gas at least a short distance from the surface of this element (27) before this liquid water undergoes significant disintegration and fragmentation. 5. Method according to claim 1, characterized in that the divergent downstream part (26) forms an included angle lying in the range from about 6 to about 14 ° · 6. Method according to claim 1, 10. characterized in that at least the diverging downstream portion (26) of the venturi-shaped conduit (20) is thermally insulated. 7, A method according to claim 1, characterized in that, practically immediately before the introduction of the hot gas stream charged with particles in the upstream converging part (22) of the venturi-shaped conduit (20), the flow of the gas stream is rectified in order to reduce turbulence and eddies. 8. Method according to any one of. Claims 1 to 7, characterized in that the hot gas stream charged with particles is a process stream for the production of oven carbon black *. 9. Integrated process for separating a particle component from a hot particle-laden gas stream, this process consisting in cooling this hot particle-laden gas stream by atomizing water therein in a liquid state so as to extract the heat from this stream by evaporation of the liquid water which is thus atomized there, then pass the stream thus cooled and charged with particles through a filtering device on canvas (15), the quantity of water thus atomized being sufficient to cool the current to a sufficiently low temperature to prevent deterioration of the fabric filtration elements * of this device (15), this temperature being however sufficiently high to maintain the prevailing atmosphere in this device (15 ) beyond the dew point of the gaseous component 5 of this particle-laden gas stream, characterized in that the hot particle-laden gas stream is cooled by passing it through tr with a relatively compact venturi-shaped conduit (20) comprising a converging upstream part (22), a diverging downstream part (26) and a throttle (24) between these two parts with this current being accelerated to a Mach number of at least about 0.25 in the throat (24) while in the latter, several streams of water to be atomized are introduced, practically transversely into the gas stream, the flow rate of the liquid water thus introduced being calculated so as to cool this current to a temperature within the above-mentioned limits * 10. Integrated process according to claim 9, characterized in that, in the throttle (24) f the hot gas stream charged with particles is accelerated to a Mach number of at least about 0.4. 11. Integrated method according to claim 9, characterized in that the canvas filtration device (15) is a bag filter. 12. Integrated method according to claim 9p characterized in that the liquid water is introduced practically transversely and towards the exterior in the gas stream through an element (27) installed at the center of the constriction (24), this element (27) _comportant several unrestricted orifices (29) oriented radially. 13. Integrated method according to claim 12, characterized in that the flow of water introduced from the element (27) is sufficient to project each of the streams of liquid water into the stream gaseous at least a short distance from the surface of this element (27) before this liquid water undergoes significant disintegration and fragmentation. 14 * Integrated method according to claim 9, characterized in that the temperature of the cooled gas stream is continuously monitored. 10 while the flow rate of the water introduced into the hot gaseous stream charged with particles is adjusted as a function of this temperature. 15. Integrated method according to claim 9, characterized in that the diverging part 15 downstream (26) forms an incited angle lying in the interval between approximately 6 and approximately 14 ° · 16. Integrated method according to claim 9, characterized in that at least the divergent downstream part (26) of the venturi-shaped duct (20) is thermally insulated. 17 · Integrated method according to claim 9p characterized in that, almost immediately before the introduction of the hot gaseous stream charged with particles in the upstream converging part (22) of the venturi-shaped conduit (20), the flow of this gas stream is corrected in order to reduce turbulence and eddies. 18. Integrated process according to one. The conch of claims 9 to 17, characterized in that the hot gas stream charged with particles is a process stream for the production of oven carbon black. 19 · Integrated system for separating a particle component from a hot gas stream charged with particles, this system comprising a duct * designed to receive a hot gas stream charged with particles, as well as an element for atomizing water in the liquid state in this gas stream flowing through this conduit in order to cool this stream by evaporation of the atomized liquid water, as well as a canvas filtration device (15) intended to receiving the gaseous stream thus cooled and charged with particles coming from this duct, as well as for separating the particle component from the gaseous component of this stream, characterized in that this duct is a duct (20) relatively com- » . pact in the form of a venturi comprising a converging upstream part (22), a diverging downstream part (26) and a constriction (24) between these two parts, '15. the dimensions and configuration of this venturi-shaped conduit (20) being designed to accelerate a hot gas stream charged with particles to a Mach number of at least about 0.25 in the throttle (24), likewise that an element with a view to introducing more than 20 streams of liquid water practically transversely into the gas stream in this constriction • (24) at a rate calculated to cool the gas stream sufficiently to prevent deterioration of the elements of canvas filtration of the canvas filtration device (15)> but maintaining the temperature of the atmosphere prevailing in this canvas filtration device (15) beyond the dew point of the gaseous component of the cooled gas stream · 20 20 · Integrated system according to claim 19, characterized in that the canvas filtration device (15) is a bag filter. 21, integrated system according to claim 19, characterized in that it also comprises a flow rectification element (18) located * practically immediately upstream of the converging upstream part (22) of the venturi-shaped duct. (20), this flow rectification element (18) being designed to attenuate turbulence and eddies in the hot gas stream charged with particles · 22. Integrated system according to claim 19, characterized in that the divergent downstream part (26) of the venturi-shaped duct (20) forms an included angle lying in the range from about 6 to about 14 ° · 23 · Integrated system according to claim 19, characterized in that the element intended to introduce several streams of liquid water comprises an element (27) situated in the center of the constriction (24) of the venturi-shaped duct (20 ), this element (27) comprising several openings (29) unrestricted oriented ra spreading, as well as a water supply line (25) communicating with this element (27), this supply line. 25) extending through a side wall of the venturi-shaped conduit (20). 24 · Integrated system according to claim 19, characterized in that it comprises a temperature detector element 25 (T) situated between the downstream end of the venturi-shaped duct (20) and the inlet of the filtration device on canvas (15)> a valve element (50) in order to regulate the flow rate of liquid water introduced into the gas stream in the screen (24), as well as a control element (51) communicating with the temperature sensing element (Tq) and Sectioning to-order. the element. ~ with valve (50) in response to the temperature detected by the element (T). o '35 m 25 # Integrated system according to claim 19, characterized in that the dimensions and configuration of the venturi-shaped duct (20) are designed poixr. accelerate the hot gas stream laden with particles 5 to a Mach number of at least about 0.4 in the throttle (24) of this conduit " 26, integrated system according to claim 19, characterized in that at least the divergent downstream part (26) of the venturi-shaped duct 10 (20) is thermally insulated " 27 "Integrated system according to claim 26, characterized in that the divergent downstream part (26) of the venturi-shaped duct (20) forms an included angle lying in the range from about 6 to about I40 · 28, Integrated system according to any one of claims 19 and 20, characterized in that it also comprises an indirect heat exchanger (9) communicating with and located upstream of the con-20 duit in the form of a venturi (20) , as well as a reactor. (l) forming carbon black from an oven communicating with and located upstream of this indirect heat exchanger (9) · 25