PROCESS FOR RECYCLING A BITUMINOUS WASTE PRODUCT SUCH AS A BITUMINOUS WASTE MEMBRANE PRODUCT

Abstract

An object of the instant application is to provide a process of recycling a bituminous product such as a waste bituminous membrane product optionally containing reinforcement layers comprising grinding and melting steps.

Claims

1-29. (canceled)

30. A process of recycling a bituminous product such as for example a waste bituminous membrane product optionally containing reinforcement layers, the process comprising the steps of: collecting waste bituminous products, preferably waste bituminous membrane products containing bituminous layers and optionally reinforcement layers characterized by sorting the waste bituminous products in a series of n waste bituminous product batch(es); a first grinding of each batch of said series of n waste bituminous product batch(es) in a knife shredder (5) for reducing the size of said each batch in a first shredded batch having a mean particle size distribution comprised between 20 and 50 cm, preferably between 20 and 40 cm; a second grinding of each first shredded batch in a rotor granulator (7) where each first shredded batch is reduced in size to a first crushed batch having a mean particle size distribution between 5 and 25 cm, preferably between 8 and 20 cm; a third grinding of each first crushed batch in a rotor granulator (8, 9) where each first crushed batch is reduced in size to a first ground batch having a mean particle size distribution between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm; conveying the each first ground batch on a vibrating sieve (12, 13) to collect each second ground batch, being each first ground batch substantially depleted from dust and particles having a particle size d100 lower than 8 mm, preferably lower than 7 mm, more preferably less than 6 mm; separating metal pieces from non-metal pieces by application of Foucault current to each second ground Table 11 Example 10 Viscosity cPS na 25° C. Pen (mean) 26 TBA (° C.) 66/76 Density 1.13 Ash (%) na Table 12 Example 11 Viscosity cPS 625 60° C. Penetrability (cm) 0.37 TBA (° C.) 61/74 Density 1.11 Ash (%) 9.68 EP 3 853 306 B1 18 5 10 15 20 25 30 35 40 45 50 55 batch and collecting each third ground batch, being each second ground batch substantially depleted from metal pieces; and introducing at least one third ground batch into a recycling unit having at least a rotor (15) and a stator (2) and an micronization chamber (20), said third ground batch being heated and melted by shear strength upon the operation of the stator (2), rotor (15) and micronization chamber (20) and collecting a melted product.

31. The process according to claim 30, wherein each third ground batch of said series of n waste bituminous product batch(es) is stored in at least one tank (14).

32. The process according to claim 30, wherein each series of n waste bituminous product batch(es) is stored under the form its said third ground batch in a tank, thereby providing n tank of waste bituminous product, containing each a waste bituminous product under its third ground batch.

33. The process according to claim 30, wherein said step of introducing at least one third ground batch into a recycling unit is a step of introducing a batch of x third ground batch(es), where x is an integer comprised between 1 and n and preferably being 1, or 3, wherein the melted product is collected in vessels, wherein the melted product is further pumped and filtrated in a bag filter, wherein the fourth bituminous product is further withdrawn by pumping in batches and filtrated in a bag filter.

34. The process according to claim 30, wherein said at least one third ground batch is fed in the recycling unit at a flow rate of 500 kg/h.

35. A recycling plant for recycling a waste bituminous product, preferably a waste bituminous membrane product containing optionally reinforcement material, the recycling plant comprising: (i) at least one recycling unit (1, 1′) comprising a first rotor housed in a first stator (2), provided with a chamber delimited by an external wall of the first rotor, wherein the chamber is a micronization chamber (20) formed by a recess arranged in a counter-element mounted on the stator (2) which is substantially cylindrical, which micronization chamber (20) comprises an adjustment means organized to adjust the volume and/or shape of the chamber and wherein at least one scraper organized to scrape the external wall of the rotor (2) is mounted downstream of the micronization chamber (20) characterized by (ii) a first grinding means (5), such as a knife shredder provided for grinding at least one batch of said series of n waste bituminous product batch(es) in a first shredded batch having a mean particle size distribution comprised between 20 and 50 cm, preferably between 20 and 40 cm, said first grinding means having a first inlet and a first exit; (iii) a second grinding means (7) such as a rotor granulator, provided for grinding at least one first shredded batch in a first crushed batch having a mean particle size distribution between 5 and 25 cm, preferably between 8 and 20 cm, said second grinding means having a second inlet and a second exit, said second inlet being connected to said first exit at least by conveying means; (iv) a third grinding means (8), such as a rotor granulator provided for grinding at least first crushed batch in a first ground batch having a mean particle size distribution between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm, said third grinding means having a third inlet and a third exit, said third inlet being connect to said second exit at least by conveying means; (v) a vibrating sieve 12) provided to convey and sieve the first ground batch and to provide a second ground batch, being the first ground batch substantially depleted from dust and particles having a particle size d100 lower than 8 mm, preferably lower than 7 mm, more preferably lower than 6 mm; and (vi) a separator provided for separating metal pieces from non-metal pieces by application of Foucault current to said second ground batch and for producing a third ground batch, being said second ground batch substantially depleted from metal pieces, said separator being connected directly or indirectly to said recycling unit in order to feed said recycling unit with at least one third ground batch.

36. The recycling plant according to claim 35, wherein said micronization chamber (20) formed by a recess is arranged in a cleat block (31) between two counter-elements (21, 21′) mounted on the stator (2).

37. The recycling plant according to claim 35, further comprising a second micronization chamber (20) or cavity 26 delimited by an external wall of the first rotor 15, said cavity 26 being formed in a recess arranged in a cleat block (31) between two counter elements 21′ and 21″. The two cleat blocks 31, 31′ (31) being made solidar one to each other and connected to a support element 23 comprising adjustment means 24 organized to adjust the EP 3 853 306 B1 19 5 10 15 20 25 30 35 40 45 50 55 volume and/or shape of the chamber and move the cleat blocks along the counter elements 21, 21′,21″.

38. The recycling plant according to claim 35, wherein the rotor is operated by a motor driving a rotation axis connected by a tight connection to the rotor (15), said motor being coupled to the rotation axis by a coupling element, said rotation axis passing through a roller bearing block disposed between the tight connection and the coupling element, said tight connection and said roller bearing block being separated by a distance d comprised between 6 and 20 cm, preferably between 7.5 and 15 cm.

39. The recycling plant according to claim 35, wherein the rotor (15) is on one end connect to a motor driving a rotation axis and on the other end connected to a dead end of said rotation axis by a tight connection to the rotor, said rotation axis dead end passing through a roller bearing block disposed between the tight connection and the end of the rotation axis, said tight connection and said roller bearing block being separated by a distance e comprised between 6 and 20 cm, preferably between 7.5 and 15 cm.

40. The recycling plant according to claim 35, wherein said tight connection comprising an O-ring cord surrounding a metal ring located around said rotation axis, said O-ring cord extending over a length of said rotation axis defined between 2 flanges.

41. The recycling plant according to claim 35, wherein, in said tight connections, at least one of the 2 flanges comprises one mobile flange provided to move along a direction parallel to the rotation axis.

42. The recycling plant according to claim 35, further comprising a second recycling unit provided with a second rotor (15) housed in a second stator (2) provided with an interchangeable micronization chamber (20), which second stator and rotor are mounted downstream of the first stator and rotor.

43. The recycling plant according to claim 42, comprising: a mixing tank located below the exit of the recycling unit having a predetermined volume, and comprising at least a first horizontal screw with mixing blades, provided to agitate a bitumen product contained in said mixing tank.

44. The recycling plant according to claim 43, wherein said mixing tank is provided with a first zone and a second zone, said first zone being above said second zone, said second zone being a bottom zone, said mixing tank having a second horizontal screw with conveying baffles inside said bottom zone, said at least first horizontal screw with mixing blades being provided inside said first zone, said second horizontal screw with conveying baffles being provided to empty the residues and the bitumen product accumulated and having sedimented in said bottom zone while said at least first horizontal screw with mixing blades being provided to agitate said bituminous product located in the first zone, each first zone and second zone being provided with an exit equipped with a valve, eventually connected to a pump, optionally, further comprising at least a bag filter, connected to the exit of the first zone of the mixing tank.

Description

[0107] Other characteristics and advantages of the present invention will be derived from the non-limitative following description, and by making reference to the drawings and the examples.

[0108] In the drawings, FIG. 1 represents a schematic flowchart view of the process according to the present invention.

[0109] FIG. 2 is a schematic flowchart view of a variant according to the present invention.

[0110] FIG. 3 is a recycling plant according to the present invention.

[0111] FIG. 4 represents a schematic view of a recycling unit having a first and a second rotor/stator assembly.

[0112] FIG. 5 represents a partial cross section of a recycling unit having a first and a second rotor/stator assembly along the line 7-7 of FIG. 6.

[0113] FIG. 6 represent a cross section along the vertical axis 19 of the rotor of the second recycling unit 1′ illustrated in FIG. 3.

[0114] FIG. 7 is an enlarged view of the rotation axis between the rotor and the motor.

[0115] FIG. 8 is a partial cross-section of a recycling plant according to the present invention showing details of the mixing tank.

[0116] FIG. 9 is a cross section of the mixing tank located below the recycling units.

[0117] FIG. 10 is a view from above of the mixing tank located below the recycling units.

[0118] In the drawings, the same reference numbers have been allocated to the same or analog element.

[0119] As it can be seen in FIG. 1, the process comprises a first step of collecting waste bituminous products, such as waste bituminous membrane products containing bituminous layers and optionally reinforcement layers (A). The collected waste bituminous used in this example contains only APP-modified bitumen waste product and can contain a) pure production waste bituminous products and/or b) cutting waste bituminous products and/or c) aged and/or degraded roofing membranes.

[0120] The waste bituminous product collected is then sorted in n batch(es) for example batch (b.sub.1), batch (b.sub.x) and batch (b.sub.n). Each batch will be treated in the plant separately even if, in some cases, it is possible to treat together waste product which are close to each other. Further in some cases, samples will be analyzed to determine the nature and the number of batch(es) (b.sub.1, b.sub.x, b.sub.n) into which the collected waste bituminous product will be sorted.

[0121] The result of the sorting step and optionally the analysis step is a series of n batch(es) of waste bituminous products (b.sub.1, b.sub.x, b.sub.n).

[0122] The batch(es) can therefore have different composition (chemical composition, age, level of contamination) with respect to each other or not depending on the nature of the collected waste bituminous product.

[0123] Also, sometimes, the collected waste bituminous products A will be inspected and will be considered enough homogeneous to be sorted in a single batch b.sub.1.

[0124] Each batch to recycle will be subjected to a first grinding step in a knife shedder where a size reduction to a d50 comprised between 20 and 50 cm to form a first shredded batch B. Accordingly, based on n batch(es) to be recycled (b.sub.1, . . . , b.sub.x, . . . , b.sub.n) will form intermediately n first shredded batch(es) (B.sub.1, bo; B.sub.x, . . . , B.sub.n). The n first shredded batch(es) (B.sub.1, . . . , B.sub.x, . . . , B.sub.n) will be conveyed by a conveying means 10 to a second grinding step. Each n first shredded batch(es) (B.sub.1, . . . , B.sub.x, . . . , B.sub.n) will be reduced in size to a n first crushed batch(es) (C.sub.1, . . . , C.sub.x, . . . , C.sub.n) where the particles have a mean particle size distribution between 5 and 25 cm, preferably between 8 and 20 cm.

[0125] The n first crushed batch(es) ((C.sub.1, . . . , C.sub.x, . . . , C.sub.n) will be conveyed by a conveying means 11 to a third grinding step. Each n first crushed batch(es) (C.sub.1, . . . , C.sub.x, . . . , C.sub.n) will be reduced in size into a first grand batch (D.sub.1, . . . , D.sub.z, D, D.sub.a) where the mean particle size distribution is between 20 and 50 mm, typically between 25 and 40 mm and more particularly between 27 and 35 mm.

[0126] Each first ground batch (D.sub.1, . . . , D.sub.x, . . . , D.sub.n) is then conveyed on a vibrating sieve 12 independently where dust and particles having a d100 lower than 8 mm, preferably lower than 7 mm, more preferably lower than 6 mm will be removed. n second ground batch(es) (E.sub.1, . . . , E.sub.x, . . . , E.sub.n) are therefore obtained respectively from the n first ground batch(es) (D.sub.1, . . . , D.sub.x, . . . , D.sub.n). Each n second ground batch(es) (E.sub.1, . . . , E.sub.x, . . . , E.sub.n) is then passed through a Foucault cage where Foucault current is applied to remove the metallic elements from each second batch(es) ((E.sub.1, . . . , E.sub.x, . . . , E.sub.n). Preferably, the ferrous metal contaminants (Fe, Ni, Cu, . . . ) are attracted and collected on one side while the non-ferrous metal contaminants (Al, Mg) are repulsed and collected on another side. The remaining particles form the third ground batch (F.sub.1, . . . , F.sub.x, . . . , F.sub.n) which is the second ground batch depleted from metal contamination. Each third ground batch (F.sub.1, . . . , F.sub.x, . . . , F.sub.n) is then stored in a storage tank or silo 60. Preferably the mixture stored in the storage tank or silo is analyzed (before or after being placed in the silo) in order to collect data pertaining to the chemical composition of the bitumen, the physical properties but also level of polymer contained.

[0127] Based on the analysis and based on the features expected from the recycled product, the operator, will then withdraw from silo's predetermined amount and prepare in a mixer 61 a mixture of several third ground batch(es) chosen amongst (B.sub.1, . . . , B.sub.x, . . . , B.sub.n) to be introduced and fed into the recycling unit 1. A melted product will be collected at the end of the recycling unit in a vessel 14.

[0128] FIG. 2 shows a variant where the batch(es) are mixed together based on predetermined ratio before being stored as a mixture of predetermined ratio of third ground batch(es) in a silo's or a storage tank 61 in order to feed the recycling unit 1 and obtain the recycled product in melted form in vessel 14.

[0129] The choice of the mixture to b performed can be dictated based on many criteria depending on: [0130] ultimate use of the recycled product [0131] level and nature of bitumen [0132] level and nature of polymer [0133] level and nature of contaminants [0134] level of recycled product in final product, . . .

[0135] As it can be seen in FIG. 3, the recycling plant is shown schematically for recycling one waste bituminous product batch such as a waste bituminous product batch such as waste bituminous membrane product batch optionally containing reinforcement material, comprises at least one recycling unit 1 comprising a housing 2′ and a feeding means 3. The housing encloses a first stator and a first rotor driven by a motor 4. The recycling plant comprises further a first grinding means 5, such as a knife shredder provided for grinding each first batch of waste bituminous product batch products 6 in a first shredded batch having a mean particle size distribution comprised between 20 and 50 cm, preferably between 20 and 40 cm. The first grinding means 5 have a first inlet for receiving the waste bituminous products 6 and a first exit for exiting the first shredded batch.

[0136] The recycling plant also comprises a second grinding means 7 such as a rotor granulator, which is, in this shown embodiment, while not being limited thereto, fed by said first shredded batch. The second grinding means 7 is provided for grinding said first shredded batch in a first crushed batch having a mean particle size distribution between 5 and 25 cm, preferably between 8 and 20 cm. The second grinding means 7 has a second inlet for accommodating the first shredded batch and a second exit for exiting the first crushed batch. The second inlet of the second grinding means is connected to the first exit of the first grinding means 5 at least by conveying means 10.

[0137] By the terms “connected”, it is meant according to the present invention that the flow of matter follows the pathway from an element A to an element B, being the same or different than A, which is connected directly or indirectly to the element A, with physical means of simply flowing from element A to element B, even if passing inside another equipment in between as additional element can be introduced between element A and B.

[0138] The recycling plant further comprises a third grinding means 8, such as a rotor granulator, provided for grinding said first crushed batch in a first ground batch having a mean particle size distribution between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm. The third grinding means 8 has a third inlet and a third exit. The third inlet is connected to the second exit of the second grinding means at least by conveying means 11.

[0139] The plant according to the present invention is also provided with a vibrating sieve 12 provided to convey and sieve the first ground batch originating from the third grinding means 8 and to provide a second ground batch, being the first ground batch substantially depleted from dust and particles having a particle size d.sub.100 lower than 8 mm, preferably lower than 7 mm and more. The vibrating sieve 12 conveys the second ground batch to a separator 9 provided for separating metal pieces from non-metal pieces by application of Foucault current to said second ground batch and for producing a third ground batch, being said second ground batch substantially depleted from metal pieces.

[0140] The third ground batch is further conveyed by means of a conveying means 13 to the feeding means 3 of the recycling unit 1.

[0141] In this shown embodiment, a vessel 14 for collecting the recycled bituminous product is provided below the recycling unit 1 where an exit is foreseen.

[0142] In FIG. 4, a detail in cross section of a first embodiment according to the present invention is shown where two recycling units 1, 1′ are present. As it can be seen in FIG. 2, each recycling unit 1, 1′ comprises comprising a first rotor 15 housed in a first stator 2. The stator 2 has a substantially cylindrical geometry that facilitates its manufacture. The input 16 and the output 17 are situated along the same vertical axis 18 which is offset with respect to the central vertical axis 19 of the rotor 15. This offset has the effect of creating, by the rotation of the rotor 15, a suction effect on the pieces of the third ground batch introduced into the input 16. It is also possible to offset the input 16 and the output 17 with respect to one another within the scope of the present invention. The stator 2 is provided with a chamber 20 delimited by an external wall of the first rotor 15. The chamber 20 is a micronization chamber 20 formed by a recess arranged between two counter-elements 21, 21′ mounted on the stator 2 which is substantially cylindrical and comprises an adjustment means 24 organized to adjust the volume and/or shape of the chamber. A good compromise shall be found between a good level of grinding of the fibers and an acceptable flowrate. If the distance between the rotor and the counter-element 21, 21′ is too low, the recycled product present a too small particle size of the fibers spread in the melted product (i.e. from reinforcement layer if present) and the flowrate of the recycling unit is too low. If the distance between the rotor and the counter-element 21, 21′ is too high, the recycled product contains long fibers but present a high flowrate in the exit.

[0143] The micronization chamber 20 allows the mass of the third ground batch introduced into the input opening 16 to accumulate there temporarily. Since the chamber 20 is delimited by the external wall of the rotor 15, the bituminous mass, which is situated in this chamber, will be driven rotationally by the rotation of the rotor 15 and thus swirl around in the chamber 20. Thus, the introduced cold third ground batch will heat up more quickly and will be triturated more easily. This is because the centrifugal force imposed on the mass by the rotor 15 will make it heat up more quickly.

[0144] The mass thus present in the chamber 20 will be mixed and/or ground in order to melt it. When the recycling unit 1 is equipped with heating means, the latter contribute towards heating said mass. The passage 22 that extends between the input opening 16 and the micronization chamber 20 is chosen to be sufficiently wide so as to facilitate access to the micronization chamber 20.

[0145] The micronization chamber 20 is mounted in an adjustable and removable manner in the stator 2. To that end, the micronization chamber 20 is mounted between two supports 23, each being provided with an adjustment means 24, for example formed by a screw and a bolt. The adjustment means 24 allow not only mounting and removal of the chamber, but also make it possible to vary of the size of the chamber by moving it nearer or further away with respect to the external wall of the rotor 15.

[0146] One end of the counter-element 21, situated downstream of the chamber 20, forms the tip of the blade of a knife which is used to shear the pieces of the third ground batch triturated in the chamber 20 more and to disintegrate the reinforcement if present in the pieces. The blade of the knife is also used to shear and pulverize the mineral covering provided on the surface of the bituminous membrane.

[0147] A deflector 25 is mounted downstream of the micronization chamber. The deflector 25 is mounted on the stator 2 and disposed in the output opening 21, along part of the external wall of the rotor 15. The deflector 25 is preferably trapezoidal in shape and delimits a first cavity 26, formed between the lower part of the support 23, the upper part of the deflector 25, the stator 2 and the rotor 15. Thus, the bituminous mass that has passed through the chamber 20 can accumulate temporarily in this first cavity 26 which thus forms a buffer. From this buffer, the melted mass will then be conveyed by the deflector 25 along the rotor 15 and will lubricate the latter.

[0148] A scraper 27 is mounted downstream of the deflector 25 also in the output opening 21. The scraper 27 and the deflector 25 are disposed so as to be at a distance from each other on opposite sides of the output opening 17. Thus, a corridor is created between the deflector 25 and the scraper 27 through which the processed material can reach the output opening 17. The scraper 27 is mounted on a support 28, using adjustment means 29. The scraper 27 is used to scrape the external wall of the rotor 15 so as to scrape the bituminous material which accumulates on this wall. Preferably the scraper 27 extends over at least part of the length of the rotor 15.

[0149] In this illustrated embodiment, two recycling unit 1 are comprised where the first and second stators 2 and rotors 15 preferably have a substantially identical construction and are placed in series so that the second recycling unit 1′ is downstream of the first recycling unit 1. Thus an output 17 of the first recycling unit 1 opens into an input 16 of the second recycling unit 1′. To facilitate understanding, the identical elements of the second member have been indicated using the same reference as that used for the first.

[0150] To recycle the bituminous product such as membrane pieces, the third ground batch is introduced into the input opening 16 of the first recycling unit 1. The rotation, indicated by the arrow 30, of the rotor 15 and the offset of the opening 16 with respect to the central axis 19 cause the suction towards the rotor 15 of the introduced third ground batch. This will at first accumulate in the opening on the external wall of the rotor which passes through the opening during its rotation. The mass can heat up more quickly if the stator 2 and rotor 15 are heated using a heating body. The heated third ground batch will then, by the rotation of the rotor 15, be driven towards the micronization chamber 20 and if applicable towards the first knife blade 21.

[0151] Preferably, the counter-element 21 and/or the stator 2 are treated with a wear-resistant substance, in particular tungsten carbide

[0152] After having passed the knife blades 21, the hot mass will temporarily accumulate in the cavity 26 in order to heat up more and reach its melting point in order to be next conveyed along the external wall of the rotor 15. The hot mass thus lubricates the rotor 15. Next, the mass reaches the corridor between the deflector 25 and the scraper 27 in order to fall into the output opening 17 under the effect of gravity. The scraper 27 takes care of scraping the external wall of the rotor, so as to prevent the mass, which is sticky because of the presence of hot bitumen, accumulating on the rotor 15 and thus preventing its rotation. The distance between the scraper 27 and the external wall of the rotor is chosen so that a little bituminous mass remains on the rotor 15 and lubricates its movement.

[0153] In this illustrated embodiment, the central vertical axis 19 of the rotor 15 of the first recycling unit 1 is aligned with the central vertical axis 19 of the rotor 15 of the second recycling unit 1′.

[0154] In a preferred embodiment illustrated in FIG. 5, the central vertical axis 19 of the rotor 15 of the first recycling unit 1 is offset with the central vertical axis 19 of the rotor 15 of the second recycling unit 1′.

[0155] As it can be seen in FIG. 5, each recycling unit 1, 1′ comprises the same elements as illustrated for the embodiment in FIG. 4. The stator 2 is provided with a chamber 20 delimited by an external wall of the first rotor 15. The chamber 20 is a micronization chamber 20 formed by a recess arranged in a cleat block 31 between two counter-elements 21, 21′ mounted on the stator 2. A second micronization chamber or cavity 26 is provided delimited by an external wall of the first rotor 15. The cavity 26 is formed in a recess arranged in a cleat block 31 between two counter elements 21′ and 21″. The two cleat block are made solidary one to each other and connected to a support element 23 comprising adjustment means 24 organized to adjust the volume and/or shape of the chamber. The adjustment means 24 can be operated manually with a wheel 34 (handwheel) or motorized wheel 34. The counter elements 21, 21′ and 21″ are a structural portion of the recycling plant and guide the cleat blocks 31 an 31′ when going forward or backward for adjustment.

[0156] The micronization chamber 20 allows the mass of the third ground batch introduced into the input opening 16 to accumulate there temporarily. Since the chamber 20 is delimited by the external wall of the rotor 15, the bituminous mass, which is situated in this chamber, will be driven rotationally by the rotation of the rotor 15 and thus swirl around in the chamber 20.

[0157] A sliding trapdoor 32 can be manually driven or by a motor 33.

[0158] As it can be seen in FIG. 6, the rotor 15 is operated by a motor 35 driving a rotation axis 36 connected by a tight connection 37 to the rotor 15. The motor 35 is coupled to the rotation axis 36 by a coupling element 38. The rotation axis 36 further passes through a roller bearing block 39 disposed between the tight connection 37 and the coupling element 38. The tight connection 37 and the roller bearing block 39 are separated by a distance d comprised between 6 and 20 cm, preferably between 7.5 and 15 cm.

[0159] It has been indeed realized according to the present invention that, contrarily to what is generally applied in mechanical engineering that providing a significant space between the tight connection 37 and the roller bearing block 39 allow to increase the efficiently of the recycling plant according to the present invention, by reducing the off period and thereby increasing drastically the operating life of the plant between two maintenance.

[0160] The rotor 15 is on one end connect to a motor 35 driving a rotation axis 36 and on the other end connected to a dead end of said rotation axis 36 by a tight connection 37 to the rotor 15. The rotation axis dead end passing through a roller bearing block 46, on the opposite side of the recycling unit 1, 1′ with respect to the side connected to the motor 35. The roller bearing block 46 is disposed between the tight connection 37 and an end of the rotation axis 36. The tight connection 37 and the roller bearing block 39 are separated by a distance e comprised between 6 and 20 cm, preferably between 7.5 and 20 cm.

[0161] The space of a distance d or the space of a distance e allows said melted product overflowing along the driving axis (rotation axis) 36 to be collected in a vessel by flowing through the space provided between the stator and the coupling element provided to couple the rotor of the recycling unit and a motor or on the opposite side between the stator 2 and the end of the driving axis (rotation axis) 36.

[0162] As it can be seen in FIG. 7, the space of a distance d provided between the tight connection 37 and the roller bearing block 39 allows hot bitumen overflowing from the rotor 15 along the rotation axis 36 to flow downwards, and hereby prevent the roller bearing 40 getting dirt and contaminated by recycled bitumen, which latter would be very detrimental to its lifetime.

[0163] As it can be seen also in FIG. 7, The tight connection 37 comprises an O-ring cord 41 surrounding a metal ring 42 located around said rotation axis 36 and extending over a length of said rotation axis 36 defined between 2 flanges 44, 45.

[0164] In a further preferred embodiment, in said tight connections, at least one the 2 flanges 44, 45 comprises one mobile flange 44 which can move along a direction parallel to the rotation axis 36 in order to reduce or to increase the distance between said 2 flanges 44, 45, for example with a tightening clamp 43.

[0165] As it can be seen in FIG. 8, a mixing tank 14 is located below the recycling units 1, 1′. The mixing tank 14 located below the exit 17 of the recycling unit 1′ has a predetermined volume, and comprise at least a first horizontal screw 47 with mixing blades 48, provided to agitate a bitumen product contained in said mixing tank 14. The mixing tank comprises heating means to provide a residence temperature comprised between 160 and 200° C., preferably between 170 and 190° C., more preferably around 180° C.

[0166] As it will be more apparent from FIGS. 8 and 9, the mixing tank 14 is provided with a first zone 49 and a second zone 50. The first zone 49 is located above said second zone 50, being a bottom zone 50. A second horizontal screw 51 with conveying baffles 52 is provided inside said bottom zone 50. The at least first horizontal screw 47 with mixing blades 48 is provided inside said first zone and the number of first horizontal screw can be higher than 1, depending on the size of the horizontal section of the first zone 49. In this preferred illustrated embodiment, the number of horizontal screw 47 with mixing blades 48 is 2.

[0167] The second horizontal screw 51 acts as a conveying means with a baffles 52 and is provided to remove any waste product located in said bottom zone 50. The crank 53 allows to open a trapdoor on the side of the recycling unit. By rotating the screw 51, the waste products is evacuated from the mixing tank. This operation is performed after having discharged the mixing tank 14.

EXAMPLES

[0168] The following recycled bitumen have been obtained from the process according to the present invention.

Example 1

[0169] 10 tons of APP waste bituminous membrane product was collected from the production facility. The collected waste product was sorted in one single batch. The batch was introduced in the plant according to the present invention and was therefore ground 3 times. The first grinding step allows to reduce the mean particle size distribution (d.sub.50) to 300 mm; the second grinding step allows to reduce the mean particle size distribution (d.sub.50) to 150 mm while the third grinding step allows to reduce the mean particle size distribution (d.sub.50) to 30 mm forming bituminous flakes. The batch was melted in the recycling plant at a temperature of about 200° C. and form the collected melted material.

[0170] The collected melted material showed the features presented in table 2.

TABLE-US-00002 Types de membranes composition R1 60° C. Penetrability 0.79 (cm) TBA (° C.) 140/152 Density 1.13 Ash (%) 27.78

Example 2

[0171] Example 1 was reproduced except that the particles were depleted in fine particles lower than 6 mm.

[0172] The collected melted material showed the features presented in table 3.

TABLE-US-00003 Example 2 Viscosity cPS 11.580 60° C. Penetrability (cm) 0.70 TBA (° C.) 141/153 Density 1.25 Ash (%) 28.88

Example 3

[0173] Example 1 was reproduced except that the waste bituminous membrane product collected was mainly used and aged APP roofing membrane from demolition site. The collected material was sorted in a single batch.

[0174] The collected melted material showed the features presented in table 4.

TABLE-US-00004 Example 3 Viscosity cPS 40.630 60° C. Penetrability (cm) 0.47 TBA (° C.) 139/149 Density 1.22 Ash (%) 29.47

Example 4

[0175] Example 3 was reproduced except that the particles were depleted in fine particles lower than 6 mm.

[0176] The collected melted material showed the features presented in table 5.

TABLE-US-00005 Example 4 Viscosity cPS na 60° C. Penetrability (cm) 0.31 TBA (° C.) 140/151 Density 1.26 Ash (%) 32.62

Example 5

[0177] 10 tons of SBS waste bituminous membrane product was collected from the production facility. The collected waste product was sorted in one single batch. The batch was introduced in the plant according to the present invention and was therefore ground 3 times. The first grinding step allows to reduce the mean particle size distribution (d.sub.50) to 300 mm; the second grinding step allows to reduce the mean particle size distribution (d.sub.50) to 150 mm while the third grinding step allows to reduce the mean particle size distribution (d.sub.50) to 30 mm forming bituminous flakes. The batch was melted in the recycling unit at a temperature of about 200° C. and form the collected melted material.

[0178] The collected melted material showed the features presented in table 6.

TABLE-US-00006 Example 5 Viscosity cPS / 60° C. Penetrability (cm) 0.79 TBA (° C.) / Density 1.29 Ash (%) 30.22

Example 6

[0179] Collected APP-modified waste membranes have been sorted by kind of waste product as production waste for the first waste bituminous membrane batch, cutting waste from construction site for the second waste bituminous membrane batch and waste membrane products from demolition site for the third waste bituminous membrane batch.

[0180] Each batch of waste has been introduced in the plant according to the present invention and was therefore ground 3 times. The first grinding step allows to reduce the mean particle size distribution (d.sub.50) to 300 mm; the second grinding step allows to reduce the mean particle size distribution (d.sub.50) to 150 mm while the third grinding step allows to reduce the mean particle size distribution (d.sub.50) to 30 mm forming bituminous flakes.

[0181] The particles of each waste product were depleted in fine particles lower than 6 mm. Each kind of waste has been grinded separately and stored in a tank.

[0182] A mixture has been prepared with specific ratio comprising 53.5% of flakes of waste product (first waste bituminous membrane batch), 16.8% flakes of cutting waste (second waste bituminous membrane batch) and 29.7% flakes of roofing waste (third waste bituminous membrane batch). The mixture has been put into the recycling unit.

[0183] The batch was melted in the recycling unit at a temperature of about 200° C. and a melted material was collected.

[0184] The collected melted material showed the features presented in table 7.

TABLE-US-00007 Example 6 Viscosity cPS 17500 60° C. Penetrability (cm) 0.63 TBA (° C.) 133/151 Density 1.23 Ash (%) 22.9

Example 7

[0185] The recycled bitumen from example 1 was collected in a mixing tank containing 50% of regular bitumen 70/100 as carrier with respect to the volume of the tank. After another 50% of the volume of the mixing tank was filled in with the recycled bitumen from example 1, the final recycled bituminous phase was obtained after continuous agitation during filling in.

[0186] The collected melted material showed the features presented in table 8.

TABLE-US-00008 Example 7 Viscosity cPS na 25° C. Penetrability (cm) 0.35 TBA (° C.) 49/70 Density 1.14 Ash (%) na

Example 8

[0187] The recycled bitumen from example 2 was used in the process of example 7.

[0188] The collected melted material showed the features presented in table 9.

TABLE-US-00009 Example 8 Viscosity cPS na 25° C. Penetrability (cm) 0.36 TBA (° C.) 45/68 Density 1.13 Ash (%) na

Example 9

[0189] The recycled bitumen from example 3 was used in the process of example 7.

[0190] The collected melted material showed the features presented in table 10.

TABLE-US-00010 Example 9 Viscosity cPS na 25° C. Penetrability (cm) 0.31 TBA (° C.) 55/75 Density 1.15 Ash (%) na

Example 10

[0191] The recycled bitumen from example 4 was used in the process of example 7.

[0192] The collected melted material showed the features presented in table 11.

TABLE-US-00011 Example 10 Viscosity cPS na 25° C. Pen (mean) 26 TBA (° C.) 66/76 Density 1.13 Ash (%) na

Example 11

[0193] The recycled bitumen from example 6 was used in the process of example 7.

[0194] The collected melted material showed the features presented in table 12.

TABLE-US-00012 Example 11 Viscosity cPS 625 60° C. Penetrability (cm) 0.37 TBA (° C.) 61/74 Density 1.11 Ash (%) 9.68

[0195] It should be understood that the present invention is not limited to the described embodiments and that variations can be applied without going outside of the scope of the appended claims.