WO2010091490A1

WO2010091490A1 - Device and method for filtration and depuration of exhaust gases from internal combustion engines

Info

Publication number: WO2010091490A1
Application number: PCT/BR2010/000043
Authority: WO
Inventors: Gilberto Leal Ribeiro
Original assignee: Miranda, Cristiane Nasser De
Priority date: 2009-02-13
Filing date: 2010-02-09
Publication date: 2010-08-19

Abstract

The device comprises: a pre-treatment means (10) to pre-humidify and pre-cool, with atomized water, the flow of hot exhaust gases from the engine (M); a flow homogenizing means (30); at least one treatment means (40) to provide a final humidification of the exhaust gas flow, the shearing of particles and the compression of said flow; an exhaust means (50) directing the treated gas flow to a lower outlet (54) for releasing water, exhaust gases containing water vapor, and solid particles; a condensing means (60) receiving the exhaust gas flow, providing the condensation of the water vapor and its collection with the particulate matter and toxic gases, and releasing the flow of depurated exhaust gas into the atmosphere; a water source (20); and a collecting reservoir (70) for water and condensate with particulate matter and dissolved toxic gases.

Description

"DEVICE AND METHOD FOR FILTRATION AND DEPURATION OF EXHAUST GASES FROM INTERNAL COMBUSTION ENGINES" Field of the Invention

The present invention relates to a device and a method to provide not only the filtration and separation of the inhalable solid particles contained in the flow of hot exhaust gases from internal combustion engines, such as diesel engines, gasoline engines, fuel oil engines or any- other internal combustion engine which burns petroleum- derived fossil fuel, but also the cooling and depuration of said exhaust gases, so as to drastically reduce the release, into the environment, of pollutant compounds, such as carbon monoxide, nitrogen oxide, sulfur dioxide, which compounds contain carcinogenic substances which are able to penetrate into the lungs when breathed in, and which are intimately associated with the so-called acid precipitations or rains. Background of the Invention It is known in the art that internal combustion engines which burn fossil fuels, as is the case of the diesel engines, produce hot exhaust gases containing pollutant particulate matter in the form of fine particles which are difficult to remove, both by means of filtration and by mechanical separation in cyclones, even when submitted to strong centrifugal force.

Measures, such as controlling vehicle circulation and equipment operation, developing less pollutant engines, installing industrial filters and the constant search for alternative fuel development, have been implemented. However, the current catalysts, as well as the so called oxicatalysts, which have been developed to reduce the pollution derived from the combustion of diesel, gasoline and fuel oil, are not satisfactory, since they reduce the engine power and do not achieve the necessary efficiency. Since said efficiency has not been achieved yet, millions of tons of particulate material and several harmful gases are still being discharged into the atmosphere. There are also known methods aiming at depurating said exhaust gases and which comprise the proceedings of making the exhaust gas flow pass through a conduit, including a converging and diverging Venturi , and supplying water to the "gorge" region of the Venturi, and then separating, from the exhaust gases, the water with the solid particles and dissolved gases.

Although proposing the humidification of the particulate matter and gases contained in the exhaust flow, with the purpose of increasing the weight of the humidified particles and dissolving the pollutant gases, this method does not allow obtaining satisfactory results, since it does not allow an effective humidification of the particulate mass, which remains with its original surface area. Moreover, the water atomization only in the Venturi region does not produce an adequate and homogeneous mixture of the water with the gases and particulate matter, reducing the degree of dissolution of the gases and the increase of the particulate matter density, with negative effects on the efficiency in separating the solid particles and washing the toxic gases. This type of solution is disclosed in patents NO-B-162530 and GB 2,300, 024.

Patent WO 99/56854 (PCT/DK99/00237) describes a method and a device for separating solid particles from a flow of hot exhaust gases of a diesel engine.

In this prior solution, the exhaust flow has its relative humidity increased by water atomization, being cooled to a temperature close to that of its dew point and then accelerated, by reducing the cross sectional area of the conduit or by a turbine, so as to provide an additional temperature reduction and water vapor condensation, making the solid particles be encapsulated in condensate droplets which can be separated from the exhaust flow by cyclone or by gravity. The solution presented in WO 99/56854 mentioned above suggests that the mixed gas flow (containing gases and particulate matter) is simultaneously humidified and cooled and then accelerated for a new cooling sufficient to provide the condensation of the water vapors and the surrounding of the solid particles by condensate droplets, allowing separating the particulate matter and the gases dissolved in the liquid phase from said mixed flow.

This prior solution also does not suggest any additional treatment of the humidified mixed flow aiming to homogenize its humidification and cooling, so as to obtain a higher degree of retention of particulate matter and toxic gases.

Brazilian patent application PI0502332-7 of the same inventor of the present invention, proposes a device directed to the same functional object and submits the exhaust gas flow to an initial step of centrifuging the mixed flow before humidifying and cooling said mixed flow, which is then submitted to the subsequent steps of diffusion, expansion, deflection, disintegration, "overflow" and new cooling of the gases before their release to the atmosphere. Apart from being complex and difficult to implement in automotive vehicles, the device as proposed in said prior Brazilian patent application does not succeed in completely eliminating the particulate matter and toxic gases from the exhaust flow released into the atmosphere. Summary of the Invention

In view of the drawbacks and deficiencies of the prior art solutions known so far for reducing pollutants in the exhaust gases from internal combustion engines fueled with diesel, gasoline, fuel oil or other petroleum- derived fossil fuels, it is an object of the present invention to provide a device for filtration and depuration of said exhaust gases, of a relatively simple and compact construction and which can be easily installed in light or heavy vehicles to be used in highways, railroads, seas and rivers, or also in movable or stationary equipment, and which allows obtaining a high degree of retention of particulate matter and toxic gases from the exhaust gas flow of said internal combustion engines provided in such vehicles or equipment .

It is also an object of the present invention to provide a device such as defined above and which permits the exhaust gas flow to be released into the atmosphere at a temperature not higher than about 50⁰C, which value can vary upwardly or downwardly in about 15 °C, depending on the ambient temperature, and with the exhaust noise emission being not higher than 60db. It is a further object of the present invention to provide a device such as defined above and which allows collecting the particulate matter and toxic gases dissolved in an aqueous washing system in a closed circuit . The invention has also the object of providing a method to carry out the filtration and depuration of exhaust gases from inner combustion engines fueled by diesel, gasoline, fuel oil or other petroleum-derived fossil fuels, in light or heavy vehicles to be used in highways, railroads, seas and river, or also in movable or stationary equipment, and which allows obtaining a high degree of retention of particulate matter and toxic gases from the exhaust gas flow of said internal combustion engines provided in such vehicles or equipment . According to a first aspect of the invention, the device for filtration and depuration of exhaust gases from internal combustion engines comprises: a pre-treatment means for pre-humidifying and pre- cooling, with atomized water, the flow of hot exhaust gases of the engine;

- a flow homogenizing means for eddying said exhaust gas flow and homogenizing it; at least one treatment means for providing the humidification, with atomized water, of the homogenized exhaust gas flow, the shearing of the solid particles and the compression of said flow until a pressure of about 8.0 Kg/cm² which can achieve about 1.2 times the discharge pressure of the engine; - an exhaust means, receiving the gas flow, at negative pressure, from the treatment means and imparting, to said gas flow, a downward path through a lower outlet for releasing water and exhaust gases containing water vapor and solid particles;

- a condensing means receiving the exhaust gas flow from the exhaust means, providing the condensation of the water vapor and its collection jointly with the particulate matter and toxic gases, and releasing the flow of depurated exhaust gases into the atmosphere.

The pre - treatment , treatment and condensing means are supplied, with water, from a water source, generally a tank. The collection of water and of the condensate which carries the particulate matter and which dissolves the toxic gases is made in a collecting reservoir.

According to a second aspect of the invention, the method for filtration and depuration of exhaust gases from internal combustion engines, as defined above, comprises the steps of : - submitting the exhaust gas flow from the engine to a pre-treatment , in order to pre-humidify and pre-cool it with atomized water;

- submitting the pre-treated exhaust gas flow to an eddy, in order to promote its homogenization,- - submitting the pre-treated and homogenized exhaust gas flow to a treatment to promote its humidification with atomized water, the shearing of the solid particles contained in the exhaust gas flow and the compression of the latter until about 8.0 Kg/cm², which can achieve about 1.2 times the discharge pressure of the engine, in order to release said gas flow after compression thereof;

- drawing, at a negative pressure, the exhaust gas flow released by the treatment means and imparting to said exhaust gas flow a downward path through an outlet for releasing water, solid particles and exhaust gases containing water vapor and solid particles; and

- condensing the exhaust gas flow already separated from the humidified particulate matter, collecting the condensate which carries the particulate matter and which dissolves the toxic gases, and releasing depurated exhaust gases into the atmosphere.

With the device and the process defined above in their basic aspects, it becomes technically and economically feasible to provide the treatment of exhaust gases from internal combustion engines which burn fuels derived from petroleum, retaining practically all the particulate matter and diluting the toxic gases contained in the flow of hot exhaust gases, which are also released at low temperatures, generally only slightly superior to the ambient temperature, greatly reducing the common odor of these gases and the noise level of the exhaust tubes. With the application of the present invention, the exhaust tube of the internal combustion engines mounted in different means of transport, equipment and installations, releases, to the environment, a flow of cleaned gases, at low temperatures and practically odorless, and which are not prejudicial to health and free of toxic gases and particulate materials, including the inhalable ones . Brief Description of the Drawings

The invention will be described below, with reference to the enclosed drawings, given by way of example of one of the possible embodiments of the proposed solution and in which :

Figure 1 represents a simplified flowchart of the means required for constructing the device and for carrying out the method for filtration and depuration of exhaust gases from internal combustion engines;

Figure 2 represents, in a somewhat enlarged scale, a diametrical longitudinal sectional view of the pre- treatment means and of the homogenizing means for the exhaust gases received from the engine; Figure 3 represents, in an enlarged scale an in a somewhat simplified way, an axial sectional view of a pair of treatment means and of the exhaust means of the present device, for providing the final humidification of the exhaust gas flow, the shearing of the solid particles contained in said flow and a compression of the latter, and also for impelling the exhaust gas flow from the treatment means to the condensing means; Figure 4 represents a diametrical cross sectional view of one of the treatment means, said section taken according to line IV-IV in figures 1 and 3 ;

Figure 5 represents, in an enlarged scale an in a somewhat simplified way, a longitudinal axial sectional view of the condensing means and of the collecting reservoir;

Figure 6 represents a somewhat simplified diametrical cross sectional view of the exhaust and the condensing means, said section taken according to line VI-VI in figure 1; and

Figure 7 represents an enlarged longitudinal sectional view of the gas releasing means, mounted downstream of the condensing means . Description of the Invention As illustrated in the drawing figures, the device for filtration and depuration of exhaust gases comprises a pre-treatment means 10 to pre-humidify and pre-cool the hot gas flow released by the engine M at temperatures which generally range from about 350°C to about 650⁰C. The pre-treatment means 10 comprises a tubular portion 11 having an inlet end 11a connected to the discharge of the engine M, an outlet end lib and a high pressure atomizing means 12, preferably a pressure in the order of 12 kgf/cm² and which is mounted internally to the tubular portion 11 and disposed to atomize water in the exhaust gas flow received from the engine M, with said atomization being made in the same direction of the exhaust gas flow. In this first step of the method for filtration and depuration of exhaust gases, the gas flow has the particulate matter pre-humidified and its whole mass pre- cooled as a function of the water atomization, allowing not only to increase the density of the particles suspended in the exhaust flow, but also the cooling of the latter to a temperature of about 65⁰C to about 95 °C, lower than the temperature at which the gas flow is received in the present device. The water atomization, in said pre-humidifying and pre- cooling step is made so as to increase the density of the particles suspended in the exhaust gas flow, as well as to reduce the temperature of said flow. The water to be atomized into the exhaust gas flow is pumped from a water source 20 which can take different forms, as described ahead. One of the forms is represented by a tank 21 mounted in the vehicle or equipment in which the present device is installed or in any support in the mounting site. The already pre-humidified and pre-cooled exhaust gas flow is then supplied to a flow homogenizing means 30 which is constructed to eddy the exhaust gas flow, provoking its homogenization. In the illustrated construction, the flow homogenizing means 30 comprises an annular tubular body 31 defined by an outer tubular wall 32 and by an inner tubular wall 33, which walls define, jointly with the end walls 34a, 34b, an outer annular chamber CE with ends closed by the end walls 34a, 34b, and an inner cylindrical chamber CI with an end closed by one of the end walls 34a and with the other end opened and defining an outlet nozzle 30b of the flow homogenizing means 30, whose inlet nozzle 30a is provided, in a substantially radial fashion, through the outer tubular wall 32. The inlet nozzle 30a of the flow homogenizing means 30 can take the form of a volute, so as to facilitate admitting the exhaust gas flow in the interior of the outer annular chamber CE for filling and pressurizing the latter, said flow being then split into multiple radial gas flows which pass through a plurality of radial tubes 35 disposed through the inner tubular wall 33 and opened to the outer annular chamber CE and to the inner cylindrical chamber CI. The construction of the flow homogenizing means 30 is made with the purpose of provoking, in the interior of the inner cylindrical chamber CI of the annular tubular body 31, a strong centripetal eddy of the multiple exhaust gas flows which are passed through the plurality of radial tubes 35, provoking a high degree of homogenization of the mass of particulate matter suspended in the already pre-humidified and pre-cooled exhaust gas flow. Thus, the inner cylindrical chamber CI of the annular tubular body 31 defines, in its interior, a region for eddying and homogenizing the exhaust gas flow, said inner cylindrical chamber CI being opened to the outlet nozzle 30b of the flow homogenizing means 30, which nozzle is opened to at least one expansion region 36, to which the already eddied and homogenized gas flow is directed.

The already pre-humidified, pre-cooled and homogenized exhaust gas flow is then conducted from the expansion region 36, generally in the form of a cross-sectional tube extension not inferior to that of the inner cylindrical chamber CI, to at least one treatment means 40, which is designed to provide a final humidification, with water, of the exhaust gas flow, the shearing of the solid particles and also the compression of said gas flow until a pressure of about 1.2 times the discharge pressure of the engine M, reaching, for example, pressures of the order of 8 kgf/cm² in diesel engines. In the illustrated construction, there are provided two treatment means 40 disposed in parallel, each receiving a respective exhaust gas flow part that is released from the homogenizing means 30 through a respective expansion region 36.

Each treatment means 40 comprises at least one rotary compressor 41, with a rotor R having a horizontal shaft 44 and multiple concentric compression stages that are maintained in radial fluid communication with each other and disposed in the interior of a tubular casing 42 provided with a generally lower radial inlet 42a for the already homogenized exhaust gas flow received from the respective expansion region 36 of the flow homogenizing means 30, and with a central axial outlet 42b (see figure 3) to release the gas flow with the already sheared, humidified and cooled particles jointly with the gaseous mass .

Still according to the exemplary construction illustrated in the drawings, each stage E of the rotor R of the rotary compressor 41 is defined between two concentric cylindrical walls 45, said stages E taking the form of concentric annular chambers, having the ends of the cylindrical walls 45 respectively attached to the end walls 46 of the rotor R, which end walls 46 close the end of the stages E. Each treatment means 40 is constructed to provide the humidification of the exhaust gas flow. Therefore, there is provided, in the interior of the tubular casing 42 of each rotary compressor 41, a water atomizing means 43, generally an atomizing nozzle disposed in the upper region of the tubular casing 42, preferably in the interior of a radial tubular projection 42c of the latter, opposite to the radial inlet 42a of the tubular casing 42. According to this construction, each rotary compressor 41, carries, externally to the cylindrical wall 45 external to the first compression stage E, a plurality of small radial blades 47 disposed so as to conduct, upon rotation of the rotary compressor 41, the humidifying water, which is sprayed into the interior of the tubular casing 42 by the atomizing means 43, to the interior of the first compression stage E, through radial holes 45a provided in said outer cylindrical wall 45 of the first compression stage E. It should be noted that the fluid communication between the compression stages E and between the last compression stage E and the central axial outlet 42b of the tubular casing 42 is defined by a plurality of radial holes 45a provided in the cylindrical side walls 45 which limit each compression stage E. The radial holes 45a are disposed offset from each other at every two adjacent compression stages E.

Thus, each rotary compressor 41 presents the multiple stages in the form of concentric annular tubular chambers radially adjacent to each other, having their ends closed by the end walls 46 of the rotor R.

Also according to the construction suggested in the enclosed drawings, each rotor R of rotary compressor 41 also comprises, in at least part of the different compression stages E, a plurality of axially disposed and angularly spaced apart shearing rods 48, and with the opposite ends attached to the respective end walls 46 of the rotor R, said shearing rods 48 rotating jointly with the rotor R, so as to impact the solid particles contained in the exhaust gas flow.

The present device further comprises a flow rectifying tube 49 disposed coaxially to the rotary compressor 41 and interconnecting its central axial outlet 42b to the radial exhaust means 50. With the constructive arrangement described above for each treatment means 40, the two rotary compressors 41 are mounted in parallel and with their central axial outlets 42b being coaxial and converging towards each other. In this construction, the combustion gas flow received in the interior of the tubular casing 42 is eddied, intensely humidified by the mixture with the humidifying water atomized into the interior of the tubular casing and conducted through the different compression stages E, upon rotation of the small radial blades 47, the gas flow being progressively compressed, passing to the first compression stage E, through the radial holes 45a provided in the outermost cylindrical side wall 45 of the rotor R. Thus, the exhaust gas flow is progressively compressed, from a stage E to the following radially innermost stage, until reaching a pressure of the order of 8 kgf/cm², the solid particles being humidified by the water atomization, at pressures of the order of 12 kgf/cm², and simultaneously and progressively sheared by the shearing rods 48 disposed in the interior of each compression stage E. At the final of the compression stages E₇ the combustion gas flow, already completely humidified, presenting an increase in the particle density and with its suspended solid particles already intensely sheared, is released through the central axial outlet 42b and directed to a radial exhaust means 50 disposed generally coaxially to the rotary compressors 41. According to the illustrated construction, the radial exhaust means 50 comprises a cylindrical casing 52 with opposite ends each coupled to a tubular casing 42 of a respective treatment means 40 and housing a rotor RE mounted in the same shaft 44 of the rotors R of the compressors 41 and having, in each end, a central axial inlet 52a for the exhaust gas flow coming from each treatment means 40, and a plurality of radial fins 55, the cylindrical casing 52 being laterally opened to a lateral volute 53 which defines a lower outlet 54 for the water and exhaust gases containing water vapor and solid particles in suspension.

As can be seen through figures 3 and 6, the exhaust flow containing water vapor and solid particles is then supplied to a condensing means 60 comprising an inlet chamber CEN, presenting an elongated annular-tubular shape and closed ends, which is horizontally disposed and which medianly and tangentially receives the exhaust gas flow released by the lower outlet 54 of the exhaust means 50. Internally to the inlet chamber CEN, the condensing means 60 comprises an also elongated annular-tubular outer chamber CEX, which is horizontally disposed and defined between an outer tubular wall 62, separating it from the inlet chamber CEN, and an inner tubular wall 63, said outer chamber CEX being closed by an end wall 64 at one of its ends.

The exhaust gas flow, which is admitted in the inlet chamber CEN, pressurizes the interior of the latter and is passed to one of the end regions of the outer chamber CEX, through a plurality of windows 65 provided in the outer tubular wall 62. In said end region of the outer chamber CEX, radially aligned with the windows 65, it is formed an atomization annular chamber CAT, which is separated from the outer chamber CEX by an annular dividing wall 66 which is trespassed by a plurality of eccentric axial tubes 67 communicating the atomization annular chamber CAT with the outer chamber CEX. On the end wall 64, common to the atomization annular chamber CAT and outer chamber CEX, there are mounted atomizing nozzles 68 to atomize water from the tank 21 into the exhaust gas flow which penetrates into the atomization annular chamber CAT, the atomization being made in the axial direction, turned to the eccentric axial tubes 67. This atomization is made at a pressure in the order of 12 kgf/cm² and with a flow rate sufficient to condense substantially the whole water vapor of the exhaust gas flow reaching the condensing means 60. The inlet chamber CEN is inferiorly provided, in its region adjacent to the windows 65 of the atomization annular chamber CAT, with a lower outlet 65a which is connected, by a conduit 65b, to the collecting reservoir 70, to conduct, gravitationally to the latter, the water, the condensate and the particulate material already radially and inferiorly released from the atomization annular chamber CAT.

The inner tubular wall 63 defines, therewithin, a tubular inner chamber CIN having an end opened to an adjacent end of the outer chamber CEX and with the opposite end projecting through the atomization annular chamber CAT, outwardly from the condensing means 60, in order to be opened to the atmosphere or even preferably connected to an exhaust means 100. The outer chamber is further provided with a plurality of parallel and spaced apart annular dividing walls 66a disposed transversally to the longitudinal axis of the outer chamber CEX. The annular dividing walls 66a define, therebetween, annular chambers CA maintained in communication by a plurality of axial tubes 67a disposed through the annular dividing walls 66a and which are maintained radially spaced from the inner tubular wall 63 and outer tubular wall 62 of the outer chamber CEX, and have their ends opened and projecting inwardly the respective annular chambers CA, the axial tubes 67a of an annular dividing wall 66a being axially offset in relation to the axial tubes 67a of the two adjacent annular dividing walls 66a.

With the construction suggested for the condensing means 60, the gas flow still containing water vapor and residual particulate matter passes through by the annular chambers CA, being progressively condensed and released, through the open end of the outer chamber CEX, to a drip- stop device 80 provided with a lower outlet 81 connected to a tube 82 which conducts the condensate, and the particulate matter suspended therein, to the collecting reservoir 70. The already cooled and depurated remaining gaseous flow can be released into the atmosphere or also preferably conducted, through the inner chamber CIN, to the exhaust means 100. It should be noted that the water to be atomized in the pre-treatment means 10, treatment means 40 and condensing means 60 is pumped from the water source 20 which, in the illustrated example, is defined by the tank 21. The pumping may be made by any adequate pump 25 and through tubes 26. The collecting reservoir 70 can be constructed in different ways, including or not a means 71 for treating the water and condensate that are collected, for example by filtration, for allowing the water used in the process to be re-used in a closed circuit, that is, returned to the tank 21. This arrangement allows great economy of the water to be used in the humidifying method, without requiring the continuous replacement of water in the tank 21, increasing the autonomy of the device, particularly when applied in automotive vehicles.

The exhaust means 100, when provided, is coupled to the outlet of the inner chamber CIN of the condensing means 60, to receive the cooled and depurated gaseous flow in the latter and submit it to an additional condensing operation, with the main purpose of catching any still remaining water, in the form of vapor, in the exhaust flow. In the illustrated construction, the gas flow which leaves the condensing means 60 is conducted, by an adequate pipe 69, to the exhaust means 100, which can take the form of a vertically disposed tubular body 101, having a lower end 101a connected to the pipe 69 and an upper end opened to the atmosphere. In its median region, the tubular body 101 houses a plurality of horizontal annular trays 102 somewhat spaced apart, through which the ascending gas flow is passed, the peripheral regions of the annular trays 102 projecting and being opened to the interior of a collecting chamber 103, surrounding the tubular body 101 and having an annular bottom wall 103a from which downwardly projects a draining tube 104 having a lower end opened to the interior of the pre-treatment means 10, downstream of the atomizing means 12 and upstream of the flow homogenizing means 30. The connection of the draining tube 104 with the tubular portion 11 of the pre-treatment means 10 is made so that the flow of exhaust gases passing through the latter operates as an ejector, producing a pressure drop in the interior of the draining tube 104 and consequently drawing back, to the device, any condensate collected in the interior of the collecting chamber 103, preventing the loss of the water used in the process for filtration and depuration of exhaust gases. With the construction proposed for the exhaust means 100, the gas flow coming from the condensing means 60 passes through the interior of the annular trays 102, in which the remaining water vapor is condensed, radially conducted to the intake chamber 103, and gravitationally and pressurizedly drawn back to the pre-treatment means 10, while the gas flow, which passes through the filter element 105 generally in the form of cartridge to be periodically replaced, is released into the atmosphere. The present equipment, by operating according to the method described herein and applied in the discharge of the exhaust gases of a 340 HP Scania diesel engine, manufactured in 1993, allowed achieving the indices of exhaust gas depuration and particulate matter retention defined below. The exhaust gases were analyzed in a gas analyzing equipment model 350-XL, provided by Testo do Brasil . The results were as described below, with the engine being fueled with diesel conventionally available in Brazil : (NOX) - 77% (NO) - 78% (NO₂) - 49% (CO) - 33% (SO₂) - 78% Particulate Matter (MP) - 80%

As it can be noted by the exemplary results showed above, the invention allows obtaining great efficiency in terms of filtration/retention of particulate matter and of depuration of toxic gases from an exhaust flow of an internal combustion engine which burns a petroleum fossil fuel.

Claims

1. A device for filtration and depuration of exhaust gases from internal combustion engines, especially diesel engines, characterized in that it comprises: - a pre-treatment means (10) for pre-humidifying and pre- cooling, with atomized water, the flow of hot exhaust gases from the engine (M) ;

- a flow homogenizing means (30) for eddying the already pre-humidified and pre-cooled exhaust gas flow, and homogenizing said flow;

- at least one treatment means (40) for providing the humidification, with atomized water, of the already pre- humidified, pre-cooled and homogenized exhaust gas flow, the shearing of the solid particles and the compression of said flow until a pressure of about 1.2 times the discharge pressure of the engine (M) ; an exhaust means (50) , receiving the gas flow, in negative pressure, from the treatment means (40) and imparting, to said gas flow, a downward path through a lower outlet (54) for releasing water and exhaust gases containing water vapor and solid particles in suspension;

- a condensing means (60) receiving the exhaust gas flow from the exhaust means (50) , providing the condensation of the water vapor and its collection jointly with the particulate matter and toxic gases, and releasing the flow of depurated exhaust gases into the atmosphere;

- a water source (20) for supplying the pre-treatment means (10), treatment means (30) and condensation means

(60) ; e - a collecting reservoir (70) for collecting water and condensate which carries the particulate matter and which dissolves the toxic gases.

2. The device, as set forth in claim 1, characterized in that the pre-treatment means (10) comprises an atomizing means (12) for atomizing water in the exhaust gas flow received from the engine (M) , said atomization being made in the same direction of said flow and upstream the flow homogenizing means (30) .

3. The device, as set forth in any of claims 1 or 2 , characterized in that the flow homogenizing means (30) comprises means to divide the exhaust gas flow into multiple flows which are subsequently joined, in an eddying and homogenizing region, with a homogenized exhaust gas flow.

4. The device, as set forth in claim 3, characterized in that the flow homogenizing means (30) comprises an annular tubular body (31) , defined by an outer tubular wall (32) and by an inner tubular wall (33) which form, jointly with end walls (34a, 34b) , an outer annular chamber (CE) with the ends closed by the end walls (34a, 34b) , and an inner cylindrical chamber (CI) with an end closed by one of the end walls (34a) and the other end opened and defining an outlet nozzle (30b) , said outer tubular wall (32) being medianly and radially provided with an inlet nozzle (30a) and also with a plurality of radial tubes (35) disposed through the inner tubular wall

(33) and opened to the outer annular chamber (CE) and inner cylindrical chamber (CI) , and said outlet nozzle (30b) being opened to at least one expansion region (36) .

5. The device, as set forth in any of claims 1, 2, 3 or 4, characterized in that the treatment means (40) comprises at least one rotary compressor (41) , having a rotor (R) with a horizontal shaft (44) and multiple concentric compression stages (E) maintained in radial fluid communication with each other and disposed in the interior of a tubular casing (42), which is provided with an atomizing means (43), disposed externally and superiorly to the rotor (R) , for atomizing the water into the interior of the tubular casing (42) ; a radial inlet (42a) for the already homogenized exhaust gas flow received from a respective expansion region (36) of the flow homogenizing means (30) ; and a central axial outlet (42b) to release the exhaust gas flow with the sheared, humidified and cooled particles jointly with the gaseous mass .

6. The device, as set forth in claim 5, characterized in that each stage (E) of the rotor (R) of the rotary compressor (41) is defined between two concentric cylindrical walls (45) , said stages (E) taking the form of concentric annular chambers, having the ends of the cylindrical walls (45) respectively attached to the end side walls (46) of the rotor (R) .

7. The device, as set forth in claim 6, characterized in that the rotary compressor (41) carries, externally to the cylindrical wall (45) external to the first compression stage (E) , a plurality of small radial blades (47) which are disposed so as to conduct, upon rotation of the rotary compressor (41) , the humidifying water, sprayed into the interior of the tubular casing (42), to the interior of the first compression stage (E) , through radial holes (45a) provided in said outer cylindrical wall (45) of the first compression stage (E) , the fluid communication between the compression stages (E) and between the last compression stage (E) and the central axial outlet (42b) of the tubular casing (42) being defined by a plurality of radial holes (45a) provided in the cylindrical side walls (45) and disposed offset from each other at every two adjacent compression stages (E) , said rotary compressor (41) also comprising, in at least part of the different compression stages (E) , a plurality of shearing rods (48) which are axially disposed, angularly spaced apart and with the opposite ends attached to the respective end walls (46) of the rotor (R) .

8. The device, as set forth in claim 7, characterized in that the it further comprises a flow rectifying tube (49) disposed coaxially to the rotary compressor (41) and connecting its central axial outlet (42b) with the radial exhaust means (50) .

9. The device, as set forth in claim 8, characterized in that it further comprises two treatment means (40) , disposed in parallel, each receiving a respective part of the exhaust gas flow coming from the flow homogenizing means (30) , through a respective expansion region (36) , and releasing an exhaust gas flow^" through a respective flow rectifying tube (49) connected to a respective side of the radial exhaust means (50) .

10. The device, as set forth in any of claims 5 to 9, characterized in that the radial exhaust means (50) comprises a cylindrical casing (52) housing a rotor (RE) which presents, at each end, a central axial inlet (52a) for the exhaust gas flow coming from each treatment means (40) , said cylindrical casing being laterally opened to a lateral volute (53) which defines a lower outlet (54) for water, exhaust gases containing water vapor and solid particles in suspension, to be directed to the condensing means (60) .

11. The device, as set forth in any of claims 1 to 10, characterized in that the condensing means (60) comprises: an inlet chamber (CEN), which has an elongated annular-tubular shape and horizontally disposed closed ends and which medianly and tangentially receives the exhaust gas flow released by the lower outlet (54) of the exhaust means (50) ; an also elongated annular-tubular outer chamber (CEX) which is horizontally disposed and defined between an outer tubular wall (62) , common to the inlet chamber (CEN) , an inner tubular wall (63) and an end wall (64), and having an end region maintained in communication with the inlet chamber (CEN) by means of a plurality of windows (65) provided in the outer tubular wall (62) ; and a tubular inner chamber (CIN) externally limited by the inner tubular wall (63) and having an end opened to an adjacent end of the end chamber (CEX) and with the opposite end projecting outwardly from the condensing means (60) and in communication with the atmosphere, the outer chamber (CEX) being provided with a lower outlet (65a, 81) in each one of its opposite end regions connected to the collecting reservoir (70) .

12. The device, as set forth in claim 11, characterized in that the end region of the outer chamber (CEX) , radially aligned with the windows (65) , forms an atomization annular chamber (CAT) , which is separated from the outer chamber (CEX) by an annular dividing wall

(66) trespassed by a plurality of eccentric axial tubes

(67) communicating the atomization annular chamber (CAT) with the outer chamber (CEX) , there being mounted, in the end wall (64) common to the atomization annular chamber (CAT) and to the outer chamber (CEX) , atomizing nozzles

(68) supplied with water from the water source (20), and with the adjacent lower outlet (65a) of the outer chamber (CEX) being provided in the inlet chamber (CEN) .

13. The device, as set forth in claim 12, characterized in that the outer chamber (CEX) is further provided with a plurality of annular dividing walls (66a) , disposed parallel and spaced apart, transversally to the longitudinal axis of the outer chamber (CEX) , and defining, therebetween, annular chambers (CA) maintained in communication by a plurality of axial tubes (67a) disposed through the annular dividing walls (66a) and maintained radially spaced from the inner tubular wall

(63) and outer tubular wall (62) of the outer chamber (CEX) and having their ends opened and projecting to the interior of the respective annular chambers (CA) , the axial tubes (67a) of an annular dividing wall (66a) being axially offset in relation to the axial tubes (67a) of the two adjacent annular dividing walls (66a), there being also provided a drip stop device (80) , simultaneously opened to the open and adjacent ends of the outer chamber (CEX) and inner chamber (CIN) and in which there is provided another lower outlet (81) of the outer chamber (CEX) to conduct the condensate and the particulate material suspended therein to the collecting reservoir (70) .

14. The device, as set forth in any of claims 1 to 13, characterized in that the condensing means (60) is opened to the atmosphere by an exhaust means (100) provided with a plurality of annular trays (102) , for radial condensation, peripherally projecting and opened to the interior of a collecting chamber (103), of water vapor condensate, which is inferiorly connected to the pre- treatment means (10) by a draining tube (104) , said exhaust means (100) further comprising a filter element (105) through which passes the exhaust gas flow to be released to the atmosphere.

15. A method for filtration and depuration of exhaust gases from internal combustion engines, especially engines diesel, characterized in that it comprises the steps of :

- submitting the exhaust gas flow from the engine to a pre-treatment by water atomization in said exhaust gas flow, so as to provide its pre-humidification and its cooling to a temperature of about 65°C to 95°C;

- submitting the pre-treated exhaust gas flow to an eddy to promote its homogenization; - submitting the pre-treated exhaust gas flow to a treatment to promote its humidification with water, the shearing of the solid particles contained in the exhaust gas flow and the compression of the latter until about 1.2 times the discharge pressure of the engine, in order to release said gas flow after its compression;

- drawing, at a negative pressure, the exhaust gas flow released by the treatment means and imparting to said exhaust gas flow a downward path through a lower outlet for releasing water, exhaust gases containing water vapor and solid particles; and

16. The method, as set forth in claim 15, characterized in that the homogenization step comprises the steps of dividing the flow of the already pre-treated exhaust gases into multiple flows in directions parallel to each other and substantially orthogonal to the direction of the single flow of pre-treated \ exhaust gases, and of joining said multiple flows, in an eddying region, in a single homogenized exhaust gas flow.

17. The method, as set forth in any of claims 15 or 16, characterized in that the treatment step comprises the steps of submitting the exhaust gas flow, already- humidified, cooled and homogenized, to a progressive acceleration and compression in contact with a load of humidifying and cooling water.

18. The method, as set forth in claim 17, characterized in that the progressive compression of the exhaust gas flow is carried out in multiple concentric compression stages, in each of them the solid particles contained in the exhaust gas flow are sheared by the impact with shearing rods moving in at least part of the compression stages .

19. The method, as set forth in any of claims 15 to 18, characterized in that the step of condensing the exhaust gas flow is carried out in a plurality of chambers disposed in series, each two adjacent chambers communicating with each other by means of a plurality of tubular extensions.

20. The method, as set forth in claim 19, characterized in that the exhaust flow, already submitted to the condensation step, is submitted to an additional condensation and to a final filtration before being released into the atmosphere, the condensate being collected and returned to the pre-treatment step.