The present invention relates to a powdered material injection device.

More in detail, the present invention relates to a device for injecting sorbents within discharge ducts of fumes resulting from combustion processes or other industrial processes in general.

The term 'sorbent' refers to a powdered material capable of absorbing and neutralising acidic components (or other substances) contained in fumes resulting from, purely by way of example, the combustion of biomass and waste.

In fact, the aforementioned processes can produce fumes containing dangerous and polluting components, which are therefore harmful to both humans and the environment. Such components are, purely by way of example, nitrogen oxides, sulphur oxides, or other substances.

In order to prevent any harmful effects resulting from a dispersion of fumes into the outside environment, sorbents are generally exploited which are capable of reacting with acidic and pollutant gases, neutralising them.

In other words, in order to avert any harmful effects resulting from a dispersion of fumes into the outside environment, sorbent powders are generally input within an ejection duct thereof.

In other words, the present invention relates to the field of devices and systems for injecting powdered reagents, such as sorbents, within ducts or tanks.

An injection system can comprise a plurality of injection lances configured to inject the sorbent within another duct or tank, imposing a turbulent motion thereto so as to favour an optimal dispersion thereof in the fumes. Disadvantageously, in this context an injection lance is subject to frequent clogging due to the narrow passage lumen for the powdered material.

Such a disadvantage, combined with the easy compactability, especially of some sorbents, translates into a decrease in the dispersion efficiency of the powdered material and in maintenance costs. In detail, a packing of powders can cause a clogging of the injection system which, as a result, not only does not ensure an optimal injection, but also requires maintenance, and thus respective costs.

An injection system can also comprise a single device comprising at least one injection duct for powdered materials, i.e., sorbents.

Today, injection systems comprising a first sorbent duct and a second air duct are exploited, both in fluid communication with an ejection duct, preferably with a fumes discharge duct.

More in detail, the sorbent duct is configured to inject sorbent powders within an ejection duct, e.g., within a fume discharge duct.

The air duct is instead configured to inject a high volumetric flow of air within the aforementioned ejection duct at the same time as the injection of sorbent: it is thereby possible to condition the flow of sorbent out of the corresponding duct, thereby favouring a good dispersion of its powders.

Generally, in order to obtain a compact injection system, the air duct is straight and of short axial length.

More in detail, the air duct is connected at one end to a fan and at a second end to a fume discharge duct.

Always in order to obtain a compact injection system, the sorbent duct comprises two arms arranged in an shape, where a first end is connected to a powdered sorbent tank, by means of a conveying pipeline, and to a pressurised gaseous substance input member configured to pneumatically convey the sorbent itself, and where a second end is connected to an ejection duct, preferably to a fume discharge duct.

Such a conformation, while space-saving, is subject to sorbent powder packing within the sorbent duct.

Disadvantageously, in fact, at the 'L-shaped' corner of the sorbent duct, the powder therefrom tends to stagnate and compact, thus generating possible clogging.

In other words, the above system, while allowing a gain in terms of space occupied, causes a cost in terms of efficiency: a packing of sorbent powder within the corresponding duct causes both a deterioration in the system's ability to disperse sorbent powders within fume discharge ducts, and maintenance costs.

In this context, US2013125749 shows a -wandless injection system comprising an air duct consisting of a straight main arm and a bifurcation thereof.

In more detail, a blowing member is connected at one end of the above- mentioned bifurcation, while the above-mentioned main arm houses a sorbent duct with a smaller cross-section.

However, the system described in US2013125749 only provides an injection system with a straight sorbent duct.

Disadvantageously, therefore, the system described in US2013125749 does not avert a possible packing of sorbent along an adduction line thereof.

Furthermore, US2013125749 provides a hopper containing sorbent powder and placed in solid particle communication with the sorbent duct.

In more detail, in US2013125749 the hopper comprises lower walls converging towards a screw conveyor: thus, the converging walls promote a powder outlet by gravity and the screw conveyor, by means of a rotation thereof, locally doses an amount of powders within the sorbent duct, the powders are then conveyed along the duct by means of injection of compressed air therein.

Disadvantageously, the presence of a hopper not only generates a scarce compactness of the system, but also causes a risk of powders packing therein.

In more detail, inside a hopper an upper layer of powders compresses a lower layer of powders due to the force of gravity, promoting the compaction of the latter and thus generating a possible packing therein. Furthermore, the presence of the sorbent dosing hopper near the injection point (generally placed in a position which is difficult to access) could force the operator to perform awkward operations in order to load the sorbent into the feeding and dosing system.

In this context, the technical task underlying the present invention is to provide a powdered material injection device which obviates the drawbacks in the prior art as described above.

In particular, it is the object of the present invention to propose a powdered material injection device which is capable of preventing any packing of powders therein.

It is further the object of the present invention to propose a powdered material injection device capable of being compact in terms of space.

It is also the object of the present invention to propose a powdered material injection device which can be supplied with different types of energy.

The technical task and the specified objects are substantially achieved by a powdered material injection device comprising the technical features set forth in claim 1 , and/or in one or more of the dependent claims, and by a powdered material injection system comprising the technical features set forth in claim 10, and/or in one or more of the dependent claims.

In particular, a powdered material injection device is provided comprising at least a first hollow duct extending between a first inlet portion and a first outlet portion.

The first inlet portion is connected, or connectable, to an input member of a pressurised gaseous substance configured to introduce and convey powdered material within the aforementioned first hollow duct.

The device further comprises at least a second hollow duct extending between a second inlet portion and a second outlet portion.

The second inlet portion is connected, or connectable, to a ventilation element configured to produce a flow of gaseous material within the aforementioned second hollow duct.

Preferably, the aforementioned ventilation element is made in the form of a fan, preferably axial, or is made in the form of an air amplifier (e.g., based on the Venturi principle).

The device is further connectable to an ejection duct placed in fluid communication with the aforementioned first and second hollow ducts.

In particular, the first hollow duct extends around a respective first rectilinear axis, defining a rectilinear line of adduction of powdered material.

The first hollow duct is also placed within the second hollow duct at least at the outlet portions of the ducts themselves.

Preferably, the aforementioned first and second outlet portions are coplanar, even more preferably they are coaxial.

In other words, the aforementioned first and second hollow ducts are not in fluid communication.

According to a first embodiment, the second hollow duct extends around a respective, at least partially curvilinear axis comprising a first portion transverse to the axis around which the first hollow duct extends and a second portion coinciding with the axis around which the first hollow duct extends.

In accordance with a second embodiment, the first and the second hollow ducts are coaxial, in other words, the first hollow duct is entirely arranged within the second hollow duct.

Preferably, the first hollow duct has a diameter of a size less than or equal to a size of a diameter of the second hollow duct.

A powdered material injection system is further provided, comprising the aforementioned powdered material injection device, an electric panel operatively connected to the powdered material injection device so as to supply electrical energy suitable for an operation thereof, and a silencer connected to the fan.

Preferably, the aforementioned system comprises a support structure on which the injection device, the electric panel and the silencer are mounted or mountable. Further features and advantages of the present invention will become more apparent from the approximate and thus non-limiting description of preferred but not exclusive embodiments of a powdered material injection device.

Such a description will be set forth herein below with reference to the accompanying drawings, provided for indicative and therefore non-limiting purposes, in which:

- figure 1 shows a side view of a first embodiment of the powdered material injection device object of the present invention;

- figure 2 shows a perspective and partially sectioned view of the first embodiment of the powdered material injection device object of the present invention;

- figure 3 shows a sectional view of a second embodiment of the powdered material injection device object of the present invention;

- figure 4 shows a perspective view of a powdered material injection system comprising the powdered material injection device object of the present invention;

- figure 5 shows a side view of a powdered material injection system comprising the powdered material injection device object of the present invention.

Referring to figures 1 to 3, an injection device 100 comprises a first hollow duct 1 configured to accommodate a flow of powdered material therein.

In other words, the hollow duct 1 defines a channel therein which is configured to accommodate a flow of powdered material.

Preferably, the aforementioned powdered material is a sorbent. Preferably, the first duct 1 has a circular section and has a constant diameter dimension.

In more detail, the duct 1 extends between a respective first inlet portion 1 a and a respective first outlet portion 1 b: the sorbent flows from the inlet portion 1 a to the outlet portion 1 b. The sorbent powders are conveyed within the hollow duct 1 in a pneumatic and dry manner.

In other words, the sorbent powder is conveyed within the first hollow duct 1 by means of the introduction of a pressurised gaseous substance, preferably air, within the duct 1 itself.

In particular, the first hollow duct 1 is connected, or connectable, to an input member 3 of a pressurised gaseous substance, which is configured to introduce and convey powdered material within the first hollow duct 1 . Preferably, the input member 3 is a propeller for pneumatically conveying sorbent, which is in turn powered by a compressor, therefore capable of introducing compressed air mixed with sorbent powder within the first hollow duct 1 , thus producing a dry pneumatic sorbent conveyor therein. Even more preferably, the input member 3 is placed at the inlet portion 1 a. Advantageously, it is possible to control the input pressure of air so as to regulate the flow of sorbent generated thereby, making it more or less intense.

Such a control can be carried out manually or by means of suitable control systems (not shown in the accompanying figures) operatively connected, or connectable, to the injection device 100.

The injection device 100 further comprises a second hollow duct 2 configured to accommodate a high volumetric flow of a gaseous substance, preferably air.

In other words, the hollow duct 2 defines a channel therein which is configured to accommodate a high volumetric flow of a gaseous substance, preferably air.

Preferably, the second duct 2 has a circular section.

In more detail, the duct 2 extends between a second inlet portion 2a and a second outlet portion 2b: the flow of air flows from the portion 2a to the portion 2b. The second duct 2 is connected, or connectable, to a ventilation element 4 configured to produce a movement of a gaseous substance, preferably air, within the duct 2 itself.

In more detail, the ventilation element 4 is connected to the duct 2 at the inlet portion 2a thereof and is configured to produce a high volumetric flow of air directed towards the outlet portion 2b.

The ventilation element 4 can be made in the form of a fan 4a operatively connected to a motor 5 configured to generate the energy required to actuate it.

Preferably, but not necessarily, the fan 4a is an axial fan.

The ventilation element 4 can also be made in the form of an air amplifier 4b, in other words, in such a case the ventilation element 4 exploits the Venturi principle.

In more detail, in the aforementioned case, the air amplifier 4b is fed with compressed air by means of a compressor 6, operatively connected to the amplifier 4b itself.

The air amplifier 4b not only causes a movement of the air introduced by means of the compressor 6 within the duct 2, but also causes an intake of air from outside within duct 2 itself.

In other words, air is released at the outlet 2b which is derived directly from the air amplifier 4b and from the air intake generated thereby.

Advantageously, it is possible to adjust the air flow generated by the ventilation element 4, making it more or less intense.

Such a control can be carried out manually or by means of suitable control systems (not shown in the accompanying figures) operatively connected, or connectable, to the injection device 100.

The first hollow duct 1 mentioned above is placed within the second hollow duct 2 at least at the first and the second outlet portions 1 b and 2b.

Preferably, the first hollow duct 1 is inserted within the second hollow duct 2 so that the respective first and second outlet portions 1 b and 2b are coplanar with each other. In other words, the first hollow duct 1 is inserted within the second hollow duct 2 so that there is no fluid communication therewith.

Still in other words, the sorbent flow and the air flow do not flow into each other within the injection device 100.

Even more preferably, the first hollow duct 1 is inserted within the second hollow duct 2 so that the respective first and second outlet portions 1 b and 2b are coaxial with each other.

The injection device 100 further comprises an ejection duct 30 placed in fluid communication with the first hollow duct 1 and the second hollow duct 2 at the respective first outlet portion 1 b and second outlet portion 2b.

The connection between the second hollow duct 2 and the ejection duct 30 is made by means of suitable connection elements configured to produce a fluid seal, for example connection flanges.

Preferably, the ejection duct 30 is a fume discharge duct.

In other words, the first outlet portion 1 b is in fluid communication with the ejection duct 30, so as to discharge sorbent powder therein, and the second outlet portion 2b is in fluid communication with the ejection duct 30, so as to discharge an air flow therein.

In more detail, since the outlet portions 1 b and 2b are coplanar, an air flow discharge within the ejection duct 30 occurs at a sorbent powder discharge within the ejection duct 30: the air flow conditions the sorbent flow, allowing a better dispersion of the powders of the latter.

Preferably, in order to further improve a dispersion of the sorbent powder within the ejection duct 30, the ventilation element 4 generates a turbulent air flow.

Advantageously, therefore, the second hollow duct 2 is configured to introduce an air flow, preferably in a turbulent regime, within a fume discharge duct, thereby enhancing a dispersion of sorbent powder within the fumes themselves, thus allowing a greater limitation of acidic components contained in the fumes themselves. Enhancing the dispersion of sorbent powder within the fumes advantageously leads to an increase in the efficacy of the injection device 100, as well as savings in terms of the amount of sorbent to be used and thus the costs for sorbent supply and spent sorbent treatment.

In more detail, generally a greater amount of sorbent is injected within an ejection duct than is necessary from a stoichiometric point of view to achieve a complete removal of pollutant components within the fumes.

In other words, generally a greater amount of sorbent is injected than, from a theoretic perspective, would satisfy a chemical reaction resulting in a complete elimination of pollutant components.

As a result, a part of unreacted sorbent, thus exhausted and to be treated for proper disposal, is generated within the ejection duct 30.

The device 100 allows an enhanced sorbent dispersion, consequently allowing a smaller amount of sorbent to be injected within the ejection duct 30.

Advantageously, therefore, the device 100 allows savings both in terms of sorbent supply costs and in costs for treating spent sorbent.

In accordance with the present invention, the first hollow duct 1 extends around a respective first rectilinear axis 'A', thereby defining a rectilinear adduction line of powdered material 'Q'.

'Adduction line' refers to a portion comprised between a sorbent tank and the ejection duct 30, within which the sorbent is released.

In more detail, in this context 'adduction line' refers to a channel defined by the first hollow duct 1 , in other words an axial cavity thereof, within which the sorbent conveyed by the air flow generated by the input member 3 flows, and is indicated in figures 1 and 3 by the arrow 'Q'.

Advantageously, the rectilinear sorbent adduction line 'Q', having no edges or curvilinear portions, avoids a stagnation and subsequent compaction of sorbent powder, which would occur in the presence of and at edges or curvilinear portions. In other words, the sorbent adduction line 'Q' allows to avoid possible packings therealong.

Advantageously, therefore, the sorbent adduction line 'Q', being rectilinear, allows to avoid decreases in the efficacy of the injection device 100 and costs in terms of maintenance thereof.

The above technical feature is fundamental, for example, in the case of hydrated lime, a sorbent used to decrease the acidity of fumes.

In more detail, hydrated lime powders are prone to compacting and, in the case of curvilinear or elbowed sorbent adduction lines, tend to stagnate in non-linear zones; over time, this phenomenon can lead to occlusions.

Advantageously, therefore, the sorbent adduction line 'Q', being rectilinear, allows to overcome the aforementioned technical drawback.

Preferably, the first hollow duct 1 has a transverse section, thus perpendicular to the axis 'A' thereof, with a diameter at least equal to half of a diameter defined in the same manner as the second hollow duct 2.

Advantageously, such a technical feature allows a further reduction in the risk of sorbent powder packing along the first hollow duct 1 : a larger dimension of a transverse section thereof, thus perpendicular to the axis 'A' thereof, translates into a passage lumen for the powdered material which is of greater dimensions.

Even more advantageously, such a technical feature allows an increase in the turbulence generated in the flow of gaseous material along the second hollow duct 2: a larger dimension of a transverse section of the duct 1 , thus perpendicular to the axis 'A' thereof, translates into a passage lumen for the gaseous material in the duct 2 of smaller dimensions, thereby generating a higher speed, and thus greater flow turbulence.

In accordance with a first embodiment of the injection device 100 illustrated in figures 1 and 2, the second hollow duct 2 extends around a respective second axis 'B' which is at least partially curvilinear.

In particular, the second axis 'B' comprises a first portion, proximal to the second inlet portion 2a, in which it extends transversally to the first axis 'A', and a second portion, proximal to the first and second outlet portions 1 b, 2b, in which it coincides with the first axis 'A'.

In other words, the first hollow duct 1 is partially inserted within the second hollow duct 2: a partial insertion of the first hollow duct 1 within the second hollow duct 2 is carried out so that it is fluid-tight, in other words, so that it does not cause material leakage.

In other words, the first hollow duct 1 defines with the second hollow duct 2 a channel for conveying air comprising a first and a second segment.

In more detail, the first segment of the channel is placed near the second inlet portion 2a, in which the axis 'B' extends transversally with respect to the axis 'A'.

At the aforementioned first segment, the second hollow duct 2 defines a channel with transverse section therein for conveying air, thus perpendicular to the axis 'B', circular and defined by an inner wall of the second hollow duct 2.

'Inner wall' is intended as a wall of the second hollow duct 2 which is proximal to the corresponding second axis 'B'.

The second segment of the channel is placed near the first and second outlet portions 1 b and 2b, where the axis 'B' coincides with the axis 'A'.

At the aforementioned second segment, the second duct 2 defines therein a channel with transverse section for conveying air, thus perpendicular to the axis 'B', annular and defined by an inner wall of the second hollow duct 2 and an outer wall of the first hollow duct 1 .

'Outer wall' is intended as a wall of the first hollow duct 1 which is distal to the corresponding first axis 'A'.

The air flow generated by the ventilation element 4, flowing from the second inlet portion 2a to the second outlet portion 2b, firstly runs through the aforementioned first circular-section segment and secondly through the aforementioned second annular-section segment.

At a junction between the first and the second segment, the channel defined by the second hollow duct 2 passes from a circular transverse section to an annular transverse section, i.e., from a transverse section of greater surface to a transverse section of smaller surface.

Consequently, the air flow therein undergoes an increase in speed generated by a passage from a transverse section of larger surface to a transverse section of smaller surface.

Such an increase in speed generates a greater turbulence in the flow, which, being released within the ejection duct 30 allows a better dispersion of the sorbent released therein.

Preferably and with reference to figure 1 , in accordance with the first embodiment above, the second axis 'B', around which the second hollow duct 2 extends, has rectilinear peripheral portions ’B1' and 'B2' and a curvilinear central portion 'B3'.

Even more preferably, the peripheral portions 'B1 ' and 'B2' are arranged in directions perpendicular to each other.

In more detail, the central portion 'B3' is placed at a junction between the aforementioned first and second segments.

Advantageously, the central portion 'B3', being curvilinear, generates a further increase in turbulence in the air flow flowing within the second duct 2 and passing thereat, further enhancing a dispersion of sorbent released within the ejection duct 30.

In accordance with the first embodiment, moreover, the ventilation element 4 is made in the form of a fan 4a connected, preferably by means of connecting flanges, to the second hollow duct 2 at the inlet portion 2a thereof.

Preferably but not necessarily, the fan 4a is of the axial type.

Advantageously, fan 4a is connected to an extension of the second hollow duct 2, consequently allowing to save space.

The fan 4a is actuated, or actuatable, by means of a respective motor 5, which is integrated in the fan 4a itself and placed axially with respect thereto.

Preferably the motor 5 is electric and comprises an inverter. Even more preferably, the actuation and the operating parameters of the electric motor 5, and consequently of the fan 4a, can be set manually or automatically by means of suitable control systems (not shown in the accompanying figures) operatively connected, or connectable, to the injection device 100.

In accordance with a second embodiment of the injection device 100 illustrated in figure 3, the second hollow duct 2 extends around a respective second rectilinear axis 'B' coinciding with the axis 'A' around which the first hollow duct 1 extends.

In other words, the first and the second hollow ducts 1 and 2 are coaxial.

In particular, the first hollow duct 1 is completely inserted within the second hollow duct 2 so that the first inlet portion 1 a is near the second inlet portion 2a and so that the first outlet portion 1 b is near the second outlet portion 2b.

Thereby, the first hollow duct 1 defines with the second hollow duct 2 a channel for conveying gaseous material, preferably air, defined by an inner wall of the second hollow duct 2 and an outer wall of the first hollow duct 1.

In other words, the channel for conveying air defined by the first and the second hollow duct 1 and 2 has a transverse section, thus perpendicular to the axis 'B'; annular.

Still in other words, the second embodiment mentioned above provides an injection device 100 which extends axially and therefore one-way, conveniently useful in cases where there is a shortage of space.

Advantageously, therefore, the device 100 allows to save space.

In accordance with the second embodiment, moreover, the ventilation element 4 is made in the form of an air amplifier 4b connected, by means of appropriate seals, to the second hollow duct 2 at the inlet portion 2a thereof. In more detail, the air amplifier 4b is placed in communication with the channel for conveying air defined by the second hollow duct 2 by means of suitable channels obtained on the second hollow duct 2.

The air amplifier 4b is powered, or powerable, by a compressor 6 operatively connected or connectable to the air amplifier 4b.

Advantageously, therefore, the device 100 in accordance with the second embodiment thereof does not require a motor coupled with the ventilation element 4, thus leading to a decrease in the space occupied by the device 100 itself.

In more detail, the air amplifier 4b is based on the Venturi principle. In other words, the air amplifier 4b, by suitably creating an air acceleration, produces an air intake within the second duct 2 and upstream of the air amplifier 4b itself.

Such behaviour allows to obtain a much greater amount of air at the second outlet portion 2b with respect to that supplied by the compressor 6 to power the air amplifier 4b.

The second hollow duct 2 also has a throttle 7 at the inlet portion 2a thereof, thus at the air amplifier 4b.

In particular, at the throttle 7, the pressure within the duct for conveying air is lower, allowing an easier introduction of air with a high volumetric flow, produced by the air amplifier 4b.

With reference to figures 4 and 5, the present invention also relates to a powdered material injection system 200.

The injection system 200 comprises the previously described injection device 100.

The injection system 200 further comprises an electric panel 201 operatively connected to the injection device 100 so as to supply electrical energy useful for an operation thereof.

Preferably, the electric panel 201 supplies electrical energy useful for the operation of the pressurised gaseous material input member 3. Preferably, the electric panel 201 supplies electrical energy useful for the operation of the compressor 6.

Preferably, the electric panel 201 supplies electrical energy useful for the operation of any control systems (not shown in the accompanying figures) operatively connected, or connectable, to the injection device 100.

Preferably, the aforementioned control systems are useful for regulating the flow of sorbent, within the first hollow duct 1 , and the flow of air, within the second hollow duct 2.

The injection system 200 further comprises a silencer 202 connected to the powdered material injection device 100.

In more detail, the silencer 202 is connected to the powdered material injection device 100 at the fan 4a.

The silencer 202 is configured to reduce noise emissions emitted by the fan 4a.

Preferably, an adapter sleeve is provided which is arranged between the fan 4a and the silencer 202, so as to define a connection therebetween.

Even more preferably, the silencer 202 is cylindrical and comprises an ogive, so as to optimise the noise-reducing function thereof.

The injection system 200 preferably also comprises a vertically extended support structure 203.

Preferably the structure 203 is made in the form of a frame.

In more detail, the injection device 100, the electric panel 201 and the silencer 202 are mounted or mountable on the structure 203.

The present invention achieves the proposed aims, overcoming the drawbacks complained of in the known art.

Advantageously, the hollow duct 1 , extending around the respective rectilinear axis 'A', defines a rectilinear adduction line of powdered material 'Q', averting a risk of powder packing therealong.

The aforementioned technical feature therefore allows a saving in terms of maintenance costs and an increase in the operating efficacy of the injection device 100. The injection device 100 is also compact in terms of space occupied.

In particular, in accordance with the first embodiment thereof, the injection device 100 comprises a fan 4a, preferably axial, which being arranged as an extension of the second hollow duct 2 results in a compactness of the device 100 itself.

In particular, in accordance with the second embodiment thereof, the injection device 100 extends axially and therefore one-way, conveniently useful in cases where there is a shortage of space.

The powdered material injection device 100 can also be supplied with different types of energy.

In more detail, the injection device 100 in accordance with the first embodiment thereof comprises a fan 4a which can be driven by means of a motor 5, while in accordance with the second embodiment thereof it comprises an air amplifier 4b which can be powered by means of a compressor 6.

The injection device 100 in accordance with the first embodiment thereof also allows an energy saving.

In more detail, the conformation of the second hollow duct 2, more specifically the axis 'B' thereof, together with a partial insertion of the first hollow duct 1 within the second hollow duct 2, define a channel for conveying a flow of gaseous material, preferably air, capable of increasing the speed thereof, thus the turbulence.

Lastly, the powdered material injection device 100 allows to obtain savings in terms of sorbent supply costs and in terms of spent sorbent treatment costs.

In fact, thanks to the conformation of the second hollow duct 2 and the arrangement of the first hollow duct 1 therein, the device 100 allows to enhance a sorbent dispersion within the ejection duct 30.