"GASIFICATION APPARATUS"

[0001] The present invention concerns a gasification apparatus, in particular for the recovery of one or more inert materials from a milled asphalt.

[0002] The milled asphalt, i.e. the product recovered from the coating of the road surface, is now largely qualified as special waste, of which the "producer" is considered to be the one who materially performs the activity of milling the road surface.

[0003] Road maintenance therefore currently entails the cost of removing the surface, and a subsequent charge for the disposal of special waste recovered by milling.

[0004] Such waste consists of an inert portion and an organic portion, a mechanical separation of which is impossible due to the close mixing between such portions.

[0005] On the other hand, the high presence of organic matrix materials and petroleum derivatives results in a high calorific value of the same materials, and therefore a high content of energy that would be desirable to exploit .

[0006] The treatment of such materials by combustion results in the formation of dangerous pollutants the emission into the atmosphere of which is absolutely prohibited, with the consequent need to install expensive and delicate abatement plants.

[0007] The method of matter and energy recovery requires a thermal treatment that, by separating the inert portion from the organic portion, allows the recovery of the latter. In order to comply with environmental regulations, however, it is necessary to limit the reaction temperature and prevent, or limit to very low values, the formation of polluting chemical compounds.

[0008] The object of the present invention is therefore to create an apparatus which, in compliance with the relevant regulations, allows the milled asphalt to be treated by recovering the inert fraction contained, and which, by using the chemical-physical characteristics of the organic or polymeric matrix portion, is able to recover the energy contained therein, while limiting the formation of polluting compounds.

[0009] In this way, in contrast to what happens according to the prior art, the milled asphalt treated with the apparatus described herein allows the inert material contained in the milled asphalt (in practice at a level qualitatively similar to a virgin inert material) to be regenerated, and also savings on the costs of gasification to be obtained by virtue of reusing the synthesis gas in combustion to feed the flame of the burner. [0010] Such object is achieved by an apparatus according to claim 1. The claims dependent on this claim show preferred embodiments.

[0011] The object of the present invention will now be described in detail, with the aid of the accompanying figures, wherein:

figures 1, 2, 3 show, respectively, a partially sectional lateral view, a view from above and a proximal front view of an apparatus object of the present invention, according to a possible embodiment;

figure 4 represents an enlargement of the sectioned area of figure 1;

- figure 5 shows a schematic diagram of the directions of displacement of the materials and the gaseous flows within the apparatus according to figure 1;

- figure 6 shows a sectional magnification of a distal area of the present apparatus, similar to that shown in figure 4;

- figure 7 shows a perspective view - with a proximal angle - of the closing member, wherein the plates or walls are clearly visible, and wherein the treatment body has been omitted for greater clarity.

[0012] In the above figures, a gasification apparatus for the separation of an inert material from mixtures comprising such material and one or more polymeric/organic materials is indicated at reference number 1.

[0013] According to an embodiment, such mixture (first and/or second, as defined below) comprises or consists of a milled asphalt recovered by mechanical removal of the layers of a road coating.

[0014] In other words, the apparatus described herein is particularly suitable for gasifying an asphalt concrete comprising inert materials - e.g. rock (such as gravel, sand, crushed stone or similar) - and polymeric/organic materials, e.g. in the form of bitumen and optional synthetic resins.

[0015] More precisely, such apparatus has been designed to gasify such polymeric/organic materials by vaporizing them in the absence of oxygen, so as not to cause unwanted combustion, to obtain an inert material at least partially free from carbon residues, for example, the aforesaid inert material in a substantially pure form.

[0016] According to an advantageous aspect of the invention, this inert material may be reused for the production of new asphalt concrete.

[0017] Such apparatus comprises a casing body 2, a treatment body 4, a burner 10, a flame propagation body 12 and adduction means of a synthesis gas.

[0018] The term "synthesis gas", in this description, means a gasification product comprising fuel gas and volatile hydrocarbons (predominantly composed of carbon and hydrogen) , and possibly carbon dust carried by the gaseous stream.

[0019] The casing body 2 extends in a tubular manner along a longitudinal axis L between a proximal portion 2 and a distal portion 2";

[0020] As far as the expression "proximal" is concerned, such term will indicate the directions or components arranged or oriented towards the burner 10; conversely, the term "distal" will indicate the opposing components or directions, oriented towards the second fixed head 40 discussed below.

[0021] Moreover, the terms "axial", "radial", "coaxial" will always refer to the longitudinal axis L, unless otherwise specified.

[0022] The treatment body 4 is contained at least in part (e.g. completely) in the casing body 2 and delimits a primary chamber 6 to gasify or transform - in the absence of oxygen - the polymeric/organic material into synthesis gas .

[0023] According to an embodiment, the treatment body 4 is substantially tubular in shape.

[0024] According to an embodiment, the casing body 2 is supported, for example, by a base or a support structure 46, with an inclination angle of the longitudinal axis

L relative to a substantially horizontal reference plane P, in the range 2-15°.

[0025] According to an embodiment, the inclination angle is within the range 3-8°.

[0026] The treatment body 4 is rotatable (e.g. with respect to the burner 10) about an axis of rotation R1 and comprises first auger means 8 protruding into the primary chamber 6 to move a first mixture and the inert material in the distal direction SI.

[0027] According to an embodiment, the first auger means are connected internally to the treatment body 4 and extend away in the direction of the longitudinal axis L.

[0028] According to an embodiment, the treatment body 4 is rotatable around an axis of rotation R1 substantially parallel to the longitudinal axis L, for example around an axis of rotation R1 coincident with such axis L.

[0029] The burner 10, is instead arranged proximally to the casing body 2, in thermal contact with the primary chamber 6.

[0030] It follows that the flame of such burner remains outside of the primary chamber 6, but such chamber receives the heat generated through conduction and/or radiation .

[0031] More precisely, the gas burner 10 is fed by a combination of a fuel (e.g. natural gas, LPG, methane, gasoline, diesel or liquid petroleum derivatives) and a combustion agent (e.g. atmospheric air or oxygen) to allow such combination to react. In the variants shown in the figures, a pump or blower 48 sends atmospheric air to the burner.

[0032] According to an embodiment, the burner 10 may therefore be fueled either with at least one liquid fuel, or with at least one gaseous fuel, or with combinations thereof in a hybrid manner.

[0033] According to an embodiment, the burner 10 is fed with the fuel through a second fuel supply line 72.

[0034] The flame propagation body 12 extends distally (according to the definition provided above) from the burner 10, to the inside of the treatment body 4 to isolate the flame from the primary chamber 6.

[0035] According to an embodiment, the flame propagation body 12 is mounted coaxially inside the treatment body 4.

[0036] According to an embodiment, the primary chamber 6 is an annular gap 18 delimited between the flame propagation body 12 and the treatment body 4.

[0037] According to an embodiment, the primary chamber 6 is maintained at a lower pressure than the pressure of a secondary chamber 28, which is delimited by the casing body 2. Solely by way of example, the pressure difference between the primary chamber 6 and the secondary chamber

28 may be equal to or greater than 0.01 bar, e.g. equal to or greater than 0.1 bar.

[0038] According to an embodiment, the lower pressure in the primary chamber 6 with respect to the secondary chamber 28 may be detected by first pressure detection means 64 of the gasification apparatus 1. For example, the first pressure detection means 64 comprise or consist of at least one deprimometer .

[0039] According to an embodiment, the secondary chamber 28 is maintained at a lower pressure than the pressure outside such chamber 28, for example with respect to an ambient pressure.

[0040] According to an embodiment, the lower pressure in the secondary chamber 28 with respect to the external or ambient pressure may be detected by second pressure detection means 66 of the gasification apparatus 1. For example, the second pressure detection means 66 comprise or consist of at least one deprimometer.

[0041] According to an embodiment, the annular gap 18 is closed distally by a closing member 20, connected between the flame propagation body 12 and the treatment body 4 to prevent at least partially the entry of oxygen into the primary chamber 6, and to allow the escape S3 of the inert material from the primary chamber 6. [0042] Therefore, according to such embodiment, the flame propagation body 12 is integral in rotation to the treatment body 4.

[0043] According to an embodiment, the closing member 20 comprises at least one wall or plate 22 that may be moved by the first auger means 8, for example in a way integral thereto, to allow the inert materials to be moved out of the primary chamber 6.

[0044] According to an embodiment, the closing body 20 has a generically glass shape.

[0045] According to an embodiment, the closing body 20 comprises a radial section 56 connected internally to the flame propagation body 12, and an axial section 58 that extends proximally from the radial section 56, so as to create a loop for the transit of the exiting inert material .

[0046] According to an embodiment, the discharge opening 60 from the primary chamber 6 is then delimited between an outer surface of the flame propagation body 12 and an inner surface of the axial section 58.

[0047] The adduction means are fluidically connected (in particular: to the primary chamber 6 and to the burner 10) to draw S2 the synthesis gas from the primary chamber 6 and to feed the flame of the burner 10 with such gas.

[0048] More precisely, the adduction means are fluidically connected to the primary chamber 6 and to the burner 10 to move the synthesis gas out of such chamber 6 and are further connected to a fuel supply line 16 which is connected to the burner 10.

[0049] According to an embodiment, the fuel supply line 16 is connected to the burner 10 upstream of the area wherein the latter generates its own flame.

[0050] According to an embodiment, the gasification apparatus 1 comprises second thermometric detection means 68 for the detection of the temperature of the synthesis gas .

[0051] In the embodiment shown in figure 3, the second thermometric detection means 68 are arranged at the fuel supply duct 16.

[0052] By way of example, the measurement signals of the second thermometric detection means 68 may be used to control a variation in the flow rate (greater or lesser) of the mixtures comprising the inert material and one or more polymeric/organic materials within the gasification apparatus 1.

[0053] According to an embodiment, the gasification apparatus 1 comprises shut-off means 74, arranged upstream of the burner 10, configured to regulate a flow rate of the fuel (e.g. gaseous and/or liquid, as discussed above) to the burner 10. For example, the shut- off means 74 could be located at the burner 10 and/or along the second fuel supply line 72 connected to the burner 10.

[0054] According to an embodiment, the gasification apparatus 1 comprises first thermometric detection means 76 functionally connected to the shut-off means 74, for example through the management and control means 70 of the apparatus 1 (only sketched in figure 3) .

[0055] According to various embodiments, the first means of thermometric detection 76 may be arranged at the burner 10, at the primary chamber 6, in at least one point of travel of the inert material into the apparatus 1, and/or in at least one discharge area 78 of the inert material from the apparatus 1.

[0056] According to an embodiment, on the basis of one or more measured temperature signals sent from the first thermometric detection means 76, the shut-off means 74 are controllable in such a way as to reduce or increase the flow rate of the fuel.

[0057] It follows that, with the same flow rate of the fuel through the fuel supply duct 72, any temperature fluctuations may be caused mainly by the flow rate of synthesis gas fed to the burner 10.

[0058] It follows that, when the solid mixtures supplied to the apparatus 1 are richer in polymeric/organic materials, a greater flow rate of synthesis gas will be generated by gasification and an increase in temperature will occur, detected by the first thermometric detection means 76. The flow rate of the fuel may thus be reduced by means of the shut-off means 74.

[0059] Conversely, when the solid mixtures supplied to the apparatus 1 are poorer in polymeric/organic materials, a smaller flow rate of synthesis gas will be generated by gasification and therefore a reduction in temperature will occur, detected by the first thermometric detection means 76. In this second circumstance, the flow rate of the fuel will therefore have to be increased by the shut ^¬ off means 74.

[0060] Therefore, the apparatus according to such embodiments is designed so that the use of liquid and/or gaseous fuel may be reduced or increased in a manner corresponding to the flow rate of synthesis gas available to burner 10.

[0061] According to an embodiment, the adduction means comprise at least one suction device 14 connected on its inlet side I to the primary chamber 6 and connected on its delivery side M to a fuel supply line 16 of the burner 10.

[0062] According to an embodiment, the suction device 14 may be functionally connected to the pressure detector means 64, for example through the management and control means 70 of the apparatus 1. In particular, according to such embodiment, the suction device 14 may be controlled by signals from the pressure detector means 64 in order to bring the pressure in the primary chamber 6 to a predefined value.

[0063] According to an embodiment, the casing body 2 delimits a first access opening 24 to introduce the first mixture into the primary chamber 6, for example positioned at the burner 10.

[0064] According to an embodiment, the casing body 2 delimits a second access opening 26 to introduce a second mixture into a secondary chamber 28 for drying inert materials, circumscribed by the casing body 2 and separated from the primary chamber 6.

[0065] According to an embodiment, the first mixture has a finer particle size than the second mixture.

[0066] According to an embodiment, the first mixture has a higher percentage by weight of polymeric/organic materials than the percentage of inert material (always with reference to the second mixture) .

[0067] According to an embodiment, the casing body 2 is integral in rotation to the treatment body 4.

[0068] In the variants shown, the casing body is connected in a rotatable manner by a first fixed head 52 (in proximal position) and a second fixed head 40 (in distal position), spaced along the longitudinal axis L. In a variant, between the heads and the casing body, fluid- tight means may be provided.

[0069] According to an embodiment, the casing body 2 comprises second auger means 30 radially protruding inwards to move the second mixture along the casing body

2.

[0070] According to an embodiment, the first auger means 8 and the second auger means 30 are mutually opposed to each other so that, by means of the aforementioned rotation R1 in a predetermined direction (for example, clockwise or counterclockwise) , the first auger means 8 are oriented so as to move the first mixture in the distal direction SI (for example, see figure 5) and the second auger means 30 are oriented so as to move the second mixture in the proximal direction S4.

[0071] According to an embodiment, the first auger means 8 and/or the second auger means 30 comprise one or more radial ribs 32, 34 arranged in a spiral or herringbone pattern, which extend from the treatment body 4 and/or the casing body 2 radially towards the longitudinal axis L.

[0072] According to an embodiment, the treatment body 4 comprises a single radial rib 32 that extends in a spiral along the entire length of such body, for example in a continuous manner.

[0073] According to an embodiment, the casing body 2 comprises a plurality of separate radial ribs 34, distributed along a spiral-shaped trajectory for one or more lengths of such body, e.g. oriented in a herringbone pattern relative to an inner surface of the casing body 2.

[0074] It should be noted that the expression "herringbone pattern" means ribs that extend radially towards the inside of the casing body 2, with an incident orientation (e.g. non-orthogonal ) relative to the inner surface of such body. According to an embodiment, the secondary chamber 28 for drying inert materials partially overlaps the primary chamber 6 in a radial direction to receive from the latter at least the inert materials of the first mixture and to dry them.

[0075] According to an embodiment, the secondary chamber 28 for drying inert materials is an annular gap 36 between the casing body 2 and the treatment body 4.

[0076] According to an embodiment, the flame propagation body 12 delimits (e.g. distally) a body inlet 38 communicating with the secondary chamber 28 for drying inert materials to allow the combustion fumes to flow

(according to the direction S5 of figure 5) into such chamber 28.

[0077] According to an embodiment, the second access opening 26 is offset axially at a distance from the body inlet 38 so that the second mixture is preheated by the combustion fumes.

[0078] According to an embodiment, the apparatus 1 comprises the second fixed head 40 connected distally to the casing body 2, which delimits a third access opening 42 to the secondary chamber 28 to introduce virgin inert material into the secondary chamber 28.

[0079] According to an embodiment, the third access opening 42 is arranged distally with respect to the second access opening 26.

[0080] According to such variant, the casing body 2 comprises advantageously radial lift pockets 44 configured in such a way (for example, with a depth and/or with an orientation) so that, during the rotation of the casing body 2, the virgin inert material is transported from such pockets 44 to a height equal to or higher than the longitudinal axis L, and emerges from such pockets 44 to penetrate the combustion fumes so as to cool the fumes and dry the virgin inert material through a gas-solid heat exchange.

[0081] In the schematic diagram in figure 5, the arrow marked with the reference S6 indicates the proximal movement of the virgin inert material which, in addition to the circumferential component, also has an axial motion component in the proximal direction.

[0082] According to an embodiment, the second fixed head 40 delimits a fourth fume outlet opening 62, fluidically communicating with the second chamber 28 to allow the evacuation of combustion gases (specifically: from the burner 10) outside the apparatus 1, for example to a purification filter (not shown) .

[0083] In the schematic diagrams in figure 5 or 6, the flue gas flow direction is indicated by the arrow S7.

[0084] In the schematic diagram of figure 5 is also shown a discharge opening 54 of inert materials, coming from the gasification in the primary chamber, and optionally to the inert materials (gasified or virgin) coming from the secondary chamber.

[0085] Innovatively, the apparatus object of the present invention allows the drawbacks related to the prior art to be fully resolved.

[0086] More precisely, the proposed apparatus allows the recovery of energetically valuable raw materials, currently used in the production of concretes, which cause significant concerns due to odors and pollution.

[0087] Advantageously, the apparatus object of the present invention makes it possible to obtain a gaseous product for gasification which is a combustible gas.

[0088] In this way, such gas may be used for the production of heat necessary to maintain the combustion of the flame .

[0089] In addition, the solid inert residue of the gasification has features not dissimilar from a virgin inert material, thus achieving a further productive advantage for downstream uses of the apparatus.

[0090] Advantageously, the apparatus object of the present invention allows the gas coming from the gasification to the burner to be reused, so as to dry the incoming inert materials. In this way, this apparatus constitutes a stand-alone unit that may be implemented in any existing machine for the production of asphalt concrete, without the need for operations to modify existing machines.

[0091] The advantages of the present apparatus are therefore not only of the thermal/energy type; the recovery of inert materials in a substantially pure form also allows the amount of inert materials required for the manufacture of new conglomerate to be reduced (with the same amount of new conglomerate manufactured) .

[0092] Advantageously, at the characteristic temperature of the gasification reaction, in the absence of oxygen, the kinetics of the thermochemical process does not cause the formation of polluting compounds, causing the splitting of the molecular bonds of the polymeric/organic material and the formation of gaseous elementary compounds, leaving however unchanged the properties of the inert material, which does not undergo any substantial transformation.

[0093] Advantageously, the synthesis gas produced in this way may be mixed with an "external" combustion gas or used exclusively to feed the burner.

[0094] According to a further advantageous aspect of the present invention, the present apparatus does not need to measure the flow rate of the synthesis gas drawn from the primary chamber but rather, indirectly, detects one or more temperature values that are an index of such flow rate equal to the flow rate of the fuel (i.e. "external") fed to the burner.

[0095] To the embodiments of the aforesaid apparatus, one skilled in the art, in order to meet specific needs, may make variations or substitutions of elements with others that are functionally equivalent.

[0096] Such variants are also contained within the scope of protection as defined by the following claims.

[0097] Moreover, each variant described as belonging to a possible embodiment may be implemented independently of the other variants described.