IT202000016162A1 - WET CYCLONE WITH INTEGRATED DEVICE FOR CONTINUOUS WASHING LIQUID REGENERATION AND DEVICE FOR RECOVERY OF THE LATENT HEAT CONTAINED IN THE GAS CURRENT. - Google Patents

Description

FIELD OF THE INVENTION

Domestic and industrial boilers fueled by wood-cellulosic biomass represent an important share of the total heating systems in some geographical areas and in rural contexts. The use of wood, pellets and agricultural by-products in heating systems? dictated by economic savings for the user, while for the environment there is? an even more benefit? important in terms of lower CO2 emissions on par? of energy produced. For one megawatt hour produced with diesel, 326 kg of CO2 are produced, 270 kg for LPG, 250 kg for methane, 29 kg for pellets and only 25 kg for wood. Added to the use for heating purposes are the biomasses used in industrial and artisanal production processes such as bread ovens and pizza ovens which mainly use natural wood and pellets. Interests of an economic nature are opposed to the negative and overt effects on human health, caused by pollution from fine particles produced by biomass combustion plants. To these sources? today attributable to 30% of fine particles present in the atmosphere in winter.

The more and more restrictive emission limits imposed by the latest regulatory decrees, DM 186/2017 put all biomass plants in operation outside the norm, with the exception of the most? modern technologies that use only class A1 pellets and which, in any case, despite the technological evolution, due to the very nature of the fuel, will continue to emit dust into the atmosphere. To the dusts of the combustion systems are added those coming from production processes, from industrial machinery.

NOTE TECHNIQUE

As ? the abatement of the dust contained in the combustion fumes is known to the state of the art, are carried out only on industrial plants or on large-sized biomass boilers, due to their high costs and their complexity. plant engineering. First cyclones are used in series which precipitate the particulate matter up to 10-20 microns, followed by electrostatic filters, bag filters and finally water scrubbers. Where are they already on domestic biomass boilers of the latest generation? low concentrations? in diffusion the use of electrostatic filters mounted directly on the base of the flues. How widespread is this device? limited by various factors, first of all the operating temperatures, which cannot exceed 200?C; require continuous maintenance by qualified operators; their efficiency decreases with the saturation of dust in the ash deposit chambers. All these additional management costs of the thermal system nullify the economic savings obtained with the use of biomass.

Expensive and bulky bag filter batteries are used on industrial machinery. Fabric and activated carbon filters are used on the extractor hoods of industrial kitchens and fryers, which run out in a short time. The device object of the present invention overcomes all these drawbacks and technical limitations. In fact, the device applied to biomass boilers in operation, to newly built boilers, to wood-fired bread and pizza ovens, causes the total elimination of the dust present in the hot fumes.

As ? known to the state of the art the result ? achieved by operating the precipitation by centrifugal and gravitational effect of the dust captured by micro drops of nebulised water which incorporate them, increasing their specific weight. The flow of water subtracts heat from the gaseous stream causing it to condense and in sequence the pressure drop of the flow and the complete fall of the dust. Applied to the emissions of production processes or processing machines, it causes the same effect on cold currents. By using solvents and specific products mixed with water or in total replacement, the device of the present invention, in addition to precipitating the dust, deodorises the gaseous streams and catalyzes the acids.

The washing and the condensation of the fumes, the separation of the gas stream from the liquid and solid part, take place in a single cyclone thanks to the centrifugal effect of the same. As ? Is the separation efficiency of the traditional tangential cyclone known to the state of the art? limited to coarse particles, the capacity? of dust capture below 10 microns and up to 2.5 microns ? limited to 60%-40%. The intervention of one or more streams of nebulized water with micro metric dimensions of the drops, is able to capture the cos? called PM10 and PM2.5.

Therefore, no devices similar or identical to the device object of the present invention are described or suggested in the art.

DESCRIPTION OF THE INVENTION

This invention will come now described, for illustrative but not limiting purposes, with particular reference to the figures of the accompanying drawings.

The device object of the present invention meets all the technical requirements as in the following functional description of figures 1-3.

The device ? consisting of:

? a central body (A) consisting of a conical configuration cyclone with a radial inlet for the flue gas stream and an axial outlet for the purified gases. The central pipe which forms the axial gas outlet touches the lower water level on the limit defined by the replenishment level.

? an aspiration unit (B) consisting of an electro-aspirator, a coupling flange, and nebulizer nozzles mounted at variable angles on the plane of the flange.

? a sand filter unit (C) mounted in line with the central body (A) of the cyclone, and coupled to it with a flange for maintenance operations.

? a group (D), containing a heat exchanger (8), mounted in line with the sand filter (C) and separated from it by an internal diaphragm.

? a recirculation pump (H) which takes the filtered and cooled water from the base of the cyclone and puts it into the device through the nozzles.

The combustion fumes coming from a biomass boiler or from a direct fire oven enter through the inlet channel (G) of the cyclone The tangential inlet gaseous stream is hit by a flow of nebulised water introduced from the nozzle (F1) into equal current to the flow of hot fumes. The flow is invested along its centrifugal path by further jets introduced by the nozzles (F2) and (F3) with an angle varying from 90?to 150? with respect to the flow plane. The water introduced condenses the fumes and precipitates the solid particles along the internal perimeter of the cyclone body (A) helping to keep the surfaces clean. The central tube (E) of the cyclone acts as an axial gas extractor, and the suction point touches the water level. The water removes dust and thermal energy from the hot fumes. To allow the same washing water to be reused, said water is made to pass continuously through a sand filter (C) and sucked into the underlying heat exchanger (D) through narrow mesh filters (7) screwed onto the diaphragm (9) which separates the two sections of the sand filter assembly (C) and heat exchanger assembly (D). The filter removes the dust particles from the liquid, keeping them inside the sand. Periodically the sand filter is regenerated by a flow of mains water which is introduced in counter-current into the filter through the manifold pipe (5) from the opening of the three-way valve (6). The counter-current flow of water washes the filter by removing the deposited dust and mud from the sand, discharging them outside the device through the header pipe (1). To prevent the washing water from rising in the cyclone chamber, between the coupling flanges (10) of the two components of the device, ? positioned a diaphragm (I) on which ? a membrane (11) is mounted which acts as a one-way check valve, blocking the flow from rising and allowing the necessary hydraulic pressure to be created inside the filter. The purified water through the narrow mesh filters (7) is sucked into section (D) of the heat exchanger (8). The heat exchanger (8) uses a thermo-vector fluid which transfers the latent heat of condensation to an auxiliary dissipator, or in parallel to the heating system or other accumulation system, thanks to the hydraulic connections (2) and (3 ). The heat exchanger (8) prevents the washing water from exceeding the boiling temperature, nullifying the primary function of condensing fluid, and from dispersing into the atmosphere as vapour. The dedusted and cooled water is re-circulated in the system again thanks to the recirculation pump (H). The replenishment of the water level inside the cyclone? guaranteed by a level sensor through the manifold pipe (4) and the connection to the mains through the three-way valve (6). The extraction of the gas stream from the cyclone? kept constant by the suction unit (B) consisting of an electro-aspirator.

Finally, the device can be used for the abatement of dust transported by gaseous streams from production processes or processing machines. By replacing the washing water, or adding solvents and deodorants to it, the system reduces the odors and other pollutants present in the gases as well as the powders. The device ? been represented in the present application as a traditional cyclone with a truncated cone base, but pu? be made entirely in a cylindrical shape, without altering its principle and efficiency. The misting nozzles can be positioned in other points of the cyclone perimeter without affecting its functioning.

AND? therefore object of the present invention is a device for regeneration of the washing liquid and recovery of the latent heat comprising:

? a central body (A), consisting of a cyclone with a conical configuration;

? a suction unit (B), consisting of an electro-aspirator;

? a sand filter (C);

? a group (D), consisting of a heat exchanger (8);

? a central tube (E);

? three nozzles (F1, F2 and F3);

? an input channel (G);

? a recirculation pump (H);

? a diaphragm (I), placed between two coupling flanges (10);

? three collector tubes (1,4 and 5);

? two hydraulic connections (1 and 2);

? a three-way valve (6);

? a narrow mesh filter (7);

? a diaphragm (9);

? a membrane (11).

AND? a further object of the present invention is a device for regeneration of the washing liquid and recovery of the latent heat, structurally compact and of contained dimensions thanks to the vertical sequence arrangement and the integrated assembly of the various elements which constitute it.

AND? a further object of the present invention is a device for regeneration of the washing liquid and recovery of the latent heat, in which the nozzles (F1, F2 and F3) introduce water having micrometric particles

AND? a further object of the present invention is a device for regeneration of the washing liquid and recovery of the latent heat, in which

the filter (C):

? continuously purifies the fluid used in the washing cycle, until saturation of said filter (C);

? is regenerated by a counter-current flow of water which rises from the collector tube (5) through the opening of the three-way valve (6), discharging water and impurities? from the header pipe (1).

AND? a further object of the present invention is a device for regeneration of the washing liquid and recovery of the latent heat, in which the heat exchanger:

? intercepts the stream of purified water subtracting thermal energy; ? transfers thermal energy through the hydraulic connections (2 and 3).

Claims (5)

1. Washing liquid regeneration and latent heat recovery device including: ? at least one central body (A), consisting of a conical configuration cyclone; ? at least one suction unit (B), consisting of an electric aspirator; ? at least one sand filter (C); ? at least one group (D), consisting of a heat exchanger (8); ? at least one central tube (E); ? at least three nozzles (F1, F2 and F3); ? at least one input channel (G); ? at least one recirculation pump (H); ? at least one diaphragm (I), interposed between the coupling flanges (10); ? at least three collector tubes (1,4 and 5); ? at least two hydraulic connections (1 and 2); ? at least one three-way valve (6); ? at least one narrow-mesh filter (7); ? at least one diaphragm (9); ? at least two coupling flanges (10); ? a membrane (11). 2. Device according to claim 1, structurally compact and of contained dimensions thanks to the arrangement in vertical sequence and to the integrated assembly of the various elements which constitute it. 3. Device of claim 1, wherein the nozzles (F1, F2 and F3) introduce water having micrometric particles 4. Device of claim 1, wherein the filter (C): ? continuously purifies the fluid used in the washing cycle, until saturation of said filter (C); ? is regenerated by a counter-current flow of water which rises from the collector tube (5) through the opening of the three-way valve (6), discharging water and impurities? from the header pipe (1). 5. Device of claim 1, wherein the heat exchanger: ? intercepts the stream of purified water subtracting thermal energy; ? transfers thermal energy through the hydraulic connections (2 and 3).