Installation and method for producing asphalt mixtures

Abstract

The asphalt production plant includes a rotating drying drum (4) for receiving asphalt aggregates and / or aggregates for heating by circulating hot gases in the rotating drying drum (4), and an electric gas heating device (6) configured to heat gases using electrical energy to obtain hot gases and supply the drying drum (4) with these hot gases.

Description

[0001] The invention relates to the field of asphalt production, in particular asphalt for road surfacing.

[0002] To produce asphalt mixes, it is possible to heat and dry aggregates and / or asphalt aggregates, obtained from the recycling of asphalt, and to mix them with a binder, such as bitumen or a synthetic binder.

[0003] Heating and drying are carried out, for example, in one or more drying drums (also called rotary kilns), each drying drum extending along a central axis inclined relative to the horizontal plane and being mounted to rotate around its central axis, by circulating hot gases in the rotating drying drum to heat and dry the aggregates and / or asphalt aggregates.

[0004] Fresh materials are introduced into each drying drum, either at the raised end or in an intermediate section of the drying drum, and hot materials are recovered at the lowered end of the drum.

[0005] Due to the rotation of the drying drum, the materials introduced into the drying drum are lifted and fall back down, forming a curtain of materials inside the drum, with the flow of hot gas passing through the curtain of materials.

[0006] Due to the tilt of the drying drum, the materials introduced into the drying drum gradually advance towards the lowered end of the drying drum.

[0007] In a "parallel flow" drying drum, the gas flow circulates in the drying drum in the direction of material advancement, i.e. from the raised end to the lowered end.

[0008] In a "counter-current" drying drum, the gas flow circulates in the drying drum in the opposite direction to the direction of material advancement, i.e. from the lowered end to the raised end.

[0009] The hot gases circulating in a dryer drum are generated using a burner located inside the dryer drum, near the raised end or the lowered end of the dryer drum depending on whether the latter is parallel-flow or counter-flow, or are generated outside the dryer drum in a hot gas generator, then conducted into the dryer drum, possibly being mixed with ambient air to lower the temperature of the hot gases before their introduction into the dryer drum.

[0010] The burner fuel is, for example, coal, heavy fuel oil, domestic fuel oil, biofuel oil, natural gas or LPG (from the English "Gasoline Propane and Light Oil").

[0011] The combustion of such fuels generates greenhouse gases. It is desirable to limit the generation of greenhouse gases during the production of asphalt.

[0012] One of the aims of the invention is to propose an asphalt production installation that limits the generation of greenhouse gases.

[0013] To this end, the invention proposes an asphalt production installation comprising a rotating drying drum intended to receive aggregates and / or asphalt aggregates for heating by circulation of hot gases in the rotating drying drum, and an electric gas heating device configured to heat gases using electrical energy to obtain hot gases and supply the drying drum with these hot gases.

[0014] Using an electric heating device helps to limit the use of fossil fuels, for example by using electrical energy produced from renewable energy sources.

[0015] The use of an electric heating device also allows for precise and optimal temperature management, leading to the production of higher quality asphalt with reduced energy consumption.

[0016] In specific embodiments, the asphalt production plant includes one or more of the following optional features, taken individually or in all technically possible combinations: The gas heating device includes a ventilation device to force the circulation of gases in the electric heating device and in the drying drum; the gas heating device includes heating elements arranged in a piping device fluidly connected to the drying drum; the electric heating device includes a thermal energy storage device configured to store thermal energy produced by the electric heating device and subsequently release it to gases to produce hot gases; the thermal energy storage device includes an enclosure within which a thermal energy storage material is disposed; the thermal energy storage material is a refractory material; the installation includes a combustion heating device comprising a burner disposed in the drying drum to generate hot gases in the drying drum orin a hot gas generator separate from the drying drum and fluidically connected to the drying drum to supply the drying drum; the installation includes a gas treatment device configured for collecting hot gases at the outlet of the drying drum and filtering the collected hot gases, and one or more fluid recycling lines, each configured to take unfiltered hot gases and / or filtered hot gases and reinject them upstream of the drying drum, preferably upstream of the electric gas heating device or into the electric gas heating device, in particular upstream of electric heating elements of the electric gas heating device and / or upstream and / or downstream of a ventilation device of the electric gas heating device; the installation is configured to supply the electric heating device with hot gases exiting the drying drum and / or with fresh gases preheated byheat exchange with the hot gases exiting the drying drum; the drying drum is a first drying drum, the asphalt production plant comprising a second drying drum separate from the first drying drum, the asphalt production plant being configured to supply the second drying drum with hot gases produced by the gas heating device supplying the first drying drum and / or by another electric gas heating device and / or by a combustion heating device comprising a burner disposed in the second drying drum and / or in a hot gas generator separate from the second drying drum and fluidly connected to the second drying drum to supply the second drying drum with hot gases; the plant comprises a first electric gas heating device to supply the first drying drum with hot gases and a second electric gas heating device forsupplying a second drum with hot gas, the first gas heating device being equipped with a first thermal energy storage device configured to store thermal energy produced by the first electric heating device and subsequently release it to gases circulating via the first electric heating device and / or the second gas heating device being equipped with a second thermal energy storage device configured to store thermal energy produced by the second electric heating device and subsequently release it to gases circulating via the second electric heating device and / or the first gas heating device and the second gas heating device sharing a common thermal energy storage device configured to store thermal energy produced by the first electric heating device and / or the second gas heating device andto return it later to gases circulating via the first electric heating device and / or to gases circulating via the second gas heating device.

[0017] The invention also relates to a process for producing asphalt mixtures comprising heating asphalt aggregates and / or granules in one or more rotating drying drums by circulating hot gases in each drying drum, the process comprising heating gases using one or more electric gas heating devices each configured to produce hot gases using electrical energy to obtain hot gases.

[0018] The invention and its advantages will be better understood upon reading the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings, in which: there Figure 1 is a schematic view of an asphalt production plant comprising a drying drum and an electric heating device to supply the drying drum with hot gases; the Figure 2 is a schematic view of an asphalt production plant comprising a drying drum and an electric heating device to supply the drying drum with hot gases, the drying drum being further equipped with a burner; the Figure 3 is a schematic view of an asphalt production plant comprising a drying drum and an electric heating device to supply the drying drum with hot gases, the electric heating device comprising a thermal storage device installed in series in a hot gas piping system; Figure 4 is a schematic view of an asphalt production plant comprising a drum dryer and an electric heating device to supply the drum dryer with hot gases, the electric heating device comprising a thermal storage device installed in parallel with a hot gas pipeline; Figure 5 is a schematic view of an asphalt production plant comprising two drying drums, each equipped with its own electric heating device for supplying hot gases; Figure 6 is a schematic view of an asphalt production plant comprising two drying drums, one equipped with an electric heating device for its hot gas supply and the other equipped with a burner for its hot gas supply; Figure 7 is a schematic view of an asphalt production plant comprising two drying drums, one equipped with an electric heating device for its hot gas supply and the other equipped with a hot gas generator fitted with a burner for its hot gas supply; the Figure 8 is a schematic view of an asphalt production plant comprising a drying drum and an electric heating device to supply the drying drum with hot gases, the electric heating device comprising a thermal storage device installed in series in a hot gas piping system, the drying drum being further equipped with a burner; Figure 9 is a schematic view of an asphalt production plant comprising a drying drum and an electric heating device to supply the drying drum with hot gases, the electric heating device comprising a thermal storage device installed in parallel with a hot gas pipeline, the drying drum being further equipped with a burner; Figure 10 is a schematic view of an asphalt production plant comprising a drying drum and an electric heating device to supply a first section of the drying drum with hot gases, the electric heating device comprising a thermal storage device installed in series in a hot gas piping system, the drying drum being further equipped with a burner forming a flame in a second section of the drying drum; the Figure 11 is a schematic view of an asphalt production plant comprising a drying drum and an electric heating device to supply a first section of the drying drum with hot gases, the electric heating device comprising a thermal storage device installed in parallel with a hot gas pipeline, the drying drum being further equipped with a burner forming a flame in a second section of the drying drum; Figures 12 And 13 are schematic views of an electric heating device equipped with an energy storage device, respectively in a thermal energy storage configuration and a heating configuration using the previously stored thermal energy.

[0019] The asphalt production plant 2 of the Figure 1 is configured for the production of asphalt, in particular road asphalt, from fresh aggregates and / or recycled fresh asphalt aggregates.

[0020] In this application, the term "fresh" means that the asphalt aggregates or granules are wet and cold and have not yet been dried - completely or partially - in the asphalt production facility.

[0021] The asphalt production plant 2 includes a drying drum 4 intended to receive aggregates G and / or asphalt aggregates AE for heating by circulation of hot gases in the drying drum 4, as illustrated by arrow H.

[0022] The dryer drum 4 is rotating.

[0023] The drying drum 4 extends along a central axis A1 and is rotatable around its central axis A1.

[0024] The central axis A1 of the drying drum 4 is inclined relative to the horizontal plane. The angle of inclination of the central axis A1 of the drying drum 4 relative to the horizontal plane is typically between 2° and 6°.

[0025] The drying drum 4 has a raised end 4A and a lowered end 4B. The raised end 4A is located at a higher altitude than the lowered end 4B.

[0026] During the rotation of the drying drum 4, the aggregates G and / or the asphalt concrete aggregates AE present in the drying drum 4 are lifted by the rotation of the drying drum 4 and fall back down, forming a curtain of aggregates G and / or asphalt concrete aggregates AE. The hot gases circulating in the drying drum 4 pass through the curtain of aggregates G and / or asphalt concrete aggregates AE, and heat the aggregates G and / or asphalt concrete aggregates AE.

[0027] During the rotation of the drying drum 4, due to the inclination of the central axis A1, the aggregates G and / or the asphalt aggregates AE present in the drying drum 4 advance progressively from the raised end 4A to the lowered end 4B of the drying drum 4.

[0028] The asphalt production facility 2 includes an electric heating device 6 configured to heat gases using electrical energy, more specifically heat generated using electricity as the energy source.

[0029] In other words, the electric heating device 6 is configured to convert electrical energy into heat and transfer the heat to gases to produce hot gases.

[0030] The gases used are, for example, air, in particular atmospheric air possibly preheated by heat exchange with hot gases, and / or recycled hot gases as will be described below.

[0031] The electric heating device 6 is fluidly connected to the drying drum 4 for supplying the drying drum 4 with hot gases produced by the electric heating device 6.

[0032] The drying drum 4 is for example of the "counter-current" type, the electric heating device 6 being fluidly connected to the lowered end 4B of the drying drum 4 for the circulation of hot gases from the lowered end 4B to the raised end 4A.

[0033] Alternatively, the drying drum 4 is for example of the "parallel flow" type, the electric heating device 2 being fluidly connected to the raised end 4A of the drying drum 4 for the circulation of hot gases from the raised end 4A to the lowered end 4B.

[0034] The electric heating device 6 includes heating elements 8. The heating elements 8 are configured to generate heat when supplied with electricity.

[0035] The heating elements 8 are for example electrical resistors and / or radiant elements.

[0036] The heating elements 8 are for example electrically connected to each other in parallel and / or in series.

[0037] The electric heating device 6 includes, for example, a ventilation device 10 configured to force the circulation of gas in contact with the heating elements 8 and then towards the drying drum 4.

[0038] When atmospheric air is used, the ventilation device 10 is configured to force the circulation of atmospheric air into contact with the heating elements 8 and then towards the drying drum 4.

[0039] The electric heating device 6 includes, for example, a piping device 12 comprising an inlet 12A for cold gases and an outlet 12B for hot gases.

[0040] Outlet 12B is fluidly connected to the drying drum 4 for supplying the drying drum 4 with the hot gases exiting the piping device 12.

[0041] The 12B outlet is fluidly connected to the lowered end 4B if the dryer drum 4 is counter-current or fluidly connected to the raised end 4A if the dryer drum 4 is parallel current.

[0042] If necessary, the ventilation device 10 is arranged at the inlet 12A of the piping device 12 to force the flow of gases from the inlet 12A to the outlet 12B.

[0043] The heating elements 8 are for example arranged in the gas piping device 12, between the inlet 12A and the outlet 12B, so that the gases flowing in the piping device 12 from the inlet 12A to the outlet 12B are heated by the heating elements 8.

[0044] The electric heating device 6 includes an electrical control unit 14 configured to control the operation of the electric heating device 6, in particular to control the supply of electricity to the heating elements 8 and, where applicable, the ventilation device 10.

[0045] The asphalt production plant 2 includes a gas treatment device 16 configured to collect and filter the hot gases exiting the drying drum 4.

[0046] The hot gases exiting the dryer drum 4 are also called exhaust gases.

[0047] The gas treatment device 16 includes a gas collector 18 disposed on the drying drum 4 to collect the hot gases exiting the drying drum 4, and a filtering device 20 configured to filter the hot gases collected by the gas collector 18.

[0048] The gas treatment device 16 preferably includes a gas exhaust stack 22 configured to vent the filtered gases.

[0049] The gas collector 18 is for example located at the end of the drying drum 4 through which the hot gases exit, namely the raised end 4A if the drying drum 4 is counter-current or the lowered end 4B if the drying drum 4 is parallel-current.

[0050] The filtering device 20 is, for example, a bag filtering device.

[0051] Optionally, the asphalt production plant 2 is configured for the recycling of hot gases exiting the drying drum 4 to the electric heating device 6, preferably before and / or after filtering the hot gases.

[0052] Unfiltered and recycled hot gases are taken from the gas treatment device 16 upstream of the filtration device 20.

[0053] The filtered and recycled hot gases are taken from the gas treatment device 16 downstream of the filtering device 20.

[0054] The asphalt production plant 2 includes, for example, one or more fluidic recycling lines 23, each configured to collect hot gases exiting the drying drum 4, before and / or after filtering in the filtering device 20, and inject these hot gases into the electric heating device 6, for example upstream of the heating elements 8 and, where a ventilation device 10 is present, downstream and / or upstream of the ventilation device 10.

[0055] In exemplary embodiments, one or each of the recycling lines 23 is configured to inject hot gases upstream of the ventilation device 10 and / or into the piping device 12 of the electric heating device 6, downstream of the ventilation device 10 and upstream of the heating elements 8.

[0056] The recycling line 23 is preferably fluidically connected downstream of the filtering device 20 to collect filtered gases. This limits the introduction of impurities into the electric heating device 6.

[0057] The recycling line 23 is preferably fluidly connected to the piping device 12 downstream of the ventilation device 10, when the latter is present, and upstream of the heating elements 8. This limits the introduction of impurities into the ventilation device 10 and the fouling of the ventilation device 10.

[0058] In examples, as illustrated on the Figure 1 , the recycling line 23 is fluidly connected downstream of the filtering device 20 to collect hot gases exiting the filtered dryer drum 4 and fluidly connected to the piping device 12 downstream of the ventilation device 10.

[0059] Optionally, the asphalt production plant 2 is configured to supply the electric heating device 6 with feed gases preheated by heat exchange with hot gases exiting the drying drum 4.

[0060] The feed gases are, for example, atmospheric air.

[0061] The preheated feed gases are for example injected into the electric heating device 6 at the inlet of the ventilation device 10 and / or into the piping device 12, downstream of the ventilation device 10.

[0062] The heat exchange with the hot gases exiting the drying drum 4 is for example carried out before or after filtering the hot gases in the filtering device 20.

[0063] The asphalt production plant 2 includes, for example, a pre-heated gas supply line 24 equipped with a heat exchanger 25 arranged for heat exchange between the feed gases circulating in the supply line 24 and hot gases exiting the drying drum 4 and configured to inject the feed gases into the electric heating device 6, for example upstream of the ventilation device 10 and / or into the piping device 12 of the electric heating device 6, downstream of the ventilation device 10 and / or upstream of the heating elements 8.

[0064] The heat exchanger 25 is for example placed on the gas treatment device 16 exiting the drum 4, for example upstream or downstream of the filtering device 20.

[0065] The 24 power line includes a 24A power input, which is, for example, an air intake to draw in atmospheric air.

[0066] The drying drum 4 is configured for example to receive fresh aggregates G at the raised end 4A of the drying drum 4 and / or in an intermediate section of the drying drum 4, via a fresh aggregates G feed ring (not shown).

[0067] The drying drum 4 is configured for example to receive fresh AE asphalt aggregates at the raised end 4A of the drying drum 4 and / or in an intermediate section of the drying drum 4, via an AE asphalt aggregate feed ring (not shown).

[0068] The electrical power supply for the electric heating device 6 is provided by an electricity source 26. The electricity source 26 is, for example, supplied with electrical energy produced from renewable energy sources (wind, photovoltaic, hydroelectric, etc.) and / or from nuclear energy sources and / or from fossil energy sources.

[0069] During operation, the drying drum 4 rotates around its central axis A1. The electric heating device 2 supplies the drying drum 4 with hot gases. Fresh aggregates G and / or fresh asphalt pavement (APE) are fed into the drying drum 4 and flow from the raised end 4A to the lowered end 4B, being heated by the hot gases. The hot aggregates G and / or hot asphalt pavement (APE) are collected at the lowered end 4B of the drying drum 4.

[0070] Preferably, the hot gases are collected and filtered by the gas treatment device 16.

[0071] Advantageously, hot gases exiting the drying drum 4, in particular filtered hot gases, are recycled back into the inlet of the drying drum 4, in particular the inlet of the electric heating device 6.

[0072] The asphalt production plant 2 of the Figure 2 differs from that of the Figure 1 in that it further comprises a combustion heating device 28 including a burner 30 for generating part of the hot gases supplying the drying drum 4 by combustion of a fuel. In operation, the burner 30 generates a flame F.

[0073] The burner 30 is for example located in the drying drum 4. The drying drum 4 is for example of the "counter-current" type and the burner 30 is located near the lowered end 4B of the drying drum 4.

[0074] Alternatively, the drying drum 4 is for example of the "parallel flow" type and the burner 30 is located near the raised end 4A of the drying drum 4.

[0075] Alternatively, the combustion heating device 28 includes a hot gas generator separate from the drying drum 4, the hot gas generator comprising a combustion chamber separate from the drying drum 4 and inside which the burner 4 is disposed and which is fluidly connected to the drying drum 4 to supply the drying drum 4 with the hot gases generated by the burner 30.

[0076] The hot gases circulating in the dryer drum 4 include the hot gases, in particular hot air, produced by the electric heating device 6, and the hot gases generated by the burner 30.

[0077] The asphalt production plant 2 of the Figure 3 differs from that of the Figure 1 in that the electric heating device 6 includes a thermal energy storage device 32 configured to temporarily store thermal energy produced by the electric heating device 6, in particular by the heating elements 8, and then release it later.

[0078] The thermal energy storage device 32 includes, for example, a storage enclosure 34 containing a storage material 36 suitable for storing thermal energy.

[0079] Storage material 36, for example, is a refractory material. Such a material can withstand high temperatures.

[0080] The thermal energy storage device 32 is for example arranged in series in the piping device 12, between the inlet 12A and the outlet 12B, so that the storage material 36 is in contact with the gases heated by the heating elements 8.

[0081] The storage enclosure 34 is fluidly connected to the drying drum 4. The storage enclosure 34 is, for example, fluidly arranged in series between the ventilation device 10 and the drying drum 4.

[0082] The heating elements 8 are for example arranged in the storage enclosure 34 or fluidically upstream of the storage enclosure 34.

[0083] The electric heating device 6 includes, for example, an insulation device 38 having an open configuration in which the storage enclosure 34 is in fluidic communication with the drying drum 4 and a closed configuration in which the fluidic communication between the storage enclosure 34 and the drying drum 4 is interrupted.

[0084] The isolation device 38 includes, for example, one or more valves, in particular a butterfly valve.

[0085] In open configuration, the gases supplied by the ventilation device 10 circulate in the piping device 12 and pass through the storage enclosure 34, being heated by the heating elements 8 (located in the storage enclosure 34 or upstream of the storage enclosure 34) and exchanging heat with the storage material 36.

[0086] In closed configuration, the gases supplied by the ventilation device 10 are mixed in the storage enclosure 34, being heated by the heating elements 8 and exchanging heat with the storage material 36 for heat storage in the storage material 36.

[0087] The electrical control unit 14 is configured to control the electric heating device 6, in particular the heating elements 8 and, where applicable, the ventilation device 10 and / or the insulation device 38, for the implementation of one or more operating modes.

[0088] The electric heating device 6 is for example configured to operate in a storage mode, in which the heating elements 8 are supplied with electrical energy to produce heat to heat the storage material 36, without supplying the drying drum 4 with hot gases produced by the electric heating device 6. Where applicable, the insulation device 38 is in a closed configuration.

[0089] The electric heating device 6 includes, for example, a direct heating operating mode, in which the heating elements 8 are supplied with electrical energy to produce heat to heat the gases, and optionally the storage material 36, with the drying drum 4 being supplied with hot gases produced by the electric heating device 6. Where applicable, the insulation device 38 is in an open configuration.

[0090] The electric heating device 6 includes, for example, an indirect heating operating mode, in which the heating elements 8 are not supplied with electrical energy, the gases being heated by the storage material 36, with the drying drum 4 being supplied with hot gases produced by the electric heating device 6. Where applicable, the insulation device 38 is in an open configuration.

[0091] The asphalt production plant 2 of the Figure 4 differs from that of the Figure 3 in that the storage enclosure 34 is fluidly connected to the piping device 12 in parallel with a heating duct 12C of the piping device 12 receiving heating elements 8.

[0092] The isolation device 38 includes a direct heating configuration in which the storage enclosure 34 is fluidically isolated from the piping device 12, such that the gases flow from the inlet 12A to the outlet 12B without passing through the storage enclosure 34.

[0093] The isolation device 38 includes a storage configuration in which the storage chamber 34 is fluidly connected to the piping device 12 while being fluidly isolated from the outlet 12B of the piping device 12, such that the gases circulate in a closed loop in the heating section 12C and the storage chamber 34 for heat storage in the storage material 36.

[0094] The insulation device 38 includes an indirect heating configuration in which the storage chamber 34 is fluidly connected to the piping device 12 by being fluidly connected to the inlet 12A and the outlet 12B of the piping device 12, such that the gases flow from the inlet 12A to the outlet 12B through the storage chamber 34 to be heated by the storage material 36.

[0095] The isolation device 38 includes for example an upstream valve 38A operable to selectively connect fluidly or isolate fluidly the storage enclosure 34 from an upstream end of the heating section 12C and / or a downstream valve 38B operable to selectively connect fluidly or isolate fluidly the storage enclosure 34 from a downstream end of the heating section 12C.

[0096] The asphalt production plant 2 of the Figure 5 differs from that of the Figure 1 in that the drying drum 4 is a first drying drum 4, the asphalt production plant comprising a second drying drum 40.

[0097] The structure and operation of the second drying drum 40 are analogous to those of the first drying drum 4.

[0098] In particular, the second drying drum 40 is rotary. The second drying drum 40 extends along a central axis A2 and rotates about its central axis A2. The central axis A2 of the second drying drum 40 is inclined relative to the horizontal plane. The angle of inclination is typically between 2° and 6°. The second drying drum 40 has a raised end 40A and a lowered end 40B. The raised end 40A is located at a higher altitude than the lowered end 40B.

[0099] During the rotation of the second drying drum 40, the aggregates and / or asphalt pavement (APP) present in the drying drum 4 are lifted by the rotation of the second drying drum 40 and fall back down, forming a curtain of aggregates G and / or AEP. The hot gases H circulating in the second drying drum 40 pass through the curtain of aggregates G and / or AEP, and heat the aggregates and / or AEP.

[0100] During the rotation of the second drying drum 40, due to the inclination of the central axis A2, the aggregates G and / or the asphalt aggregates AE present in the second drying drum 40 advance progressively from the raised end 40A to the lowered end 40B of the second drying drum 40.

[0101] The asphalt production plant 2 includes, for example, an additional electric heating device 42 for the production of at least part of the hot gases supplying the second drying drum 40, separate from the electric heating device 6 for the production of at least part of the hot gases supplying the first drying drum 4.

[0102] The additional electric heating device 42 is, for example, analogous to that of the Figure 1 or that of the Figure 2 .

[0103] The second drying drum 40 is for example of the "parallel flow" type, the additional electric heating device 42 being fluidly connected to the raised end 40A of the second drying drum 40 for the circulation of hot gases from the raised end 40A to the lowered end 40B.

[0104] Alternatively, the second drying drum 40 is for example of the "counter-current" type, the additional electric heating device 42 being fluidly connected to the lowered end 40B of the second drying drum 40 for the circulation of hot gases from the lowered end 40B to the raised end 40A.

[0105] The first drying drum 4 is for example used to heat the AE asphalt aggregates and the second drying drum 40 is for example used to heat the G aggregates.

[0106] The gas treatment device 16 is configured to collect the hot gases exiting the first drying drum 4 and / or the second drying drum 40, preferably the hot gases exiting the first drying drum 4 and the second drying drum 40.

[0107] One or more fluidic recycling lines 23 are for example configured to recycle the collected gases, preferably filtered, at the inlet of the first drying drum 4 and / or the second drying drum 40, preferably at the inlet of the first drying drum 4 and the second drying drum 40.

[0108] In examples not shown, the electric gas heating device 6 supplying the first drying drum 4 is provided with a thermal energy storage device 32 and / or the electric gas heating device 6 supplying the second drying drum 40 is provided with a thermal energy storage device 32.

[0109] The asphalt production facilities 2 of Figures 6 And 7 differ from that of the Figure 4 in that the electric heating device equipping the second drying drum 40 is replaced by a combustion heating device 28 comprising a burner 30 to generate part of the hot gases supplying the second drying drum 40.

[0110] As illustrated on the Figure 6 , the burner 30 is for example disposed in the second drying drum 40. The second drying drum 40 is for example of the "parallel current" type and the burner 30 is disposed near the raised end 40A of the second drying drum 40.

[0111] Alternatively, the second drying drum 40 is for example of the "counter-current" type, with the burner 30 being located near the lowered end 40B of the second drying drum 40.

[0112] Alternatively, as illustrated on the Figure 7 The combustion heating device 28 includes a hot gas generator 44 separate from the second drying drum 40, the hot gas generator 44 comprising a combustion chamber 46 inside which the burner 30 is disposed and which is fluidly connected to the second drying drum 40 to supply the second drying drum 40 with the hot gases generated by the burner 30.

[0113] The first drying drum 4 is for example used to heat the AE asphalt aggregates and the second drying drum 40 is for example used to heat the G aggregates.

[0114] Optionally, as illustrated on the Figures 5 à 7 , the asphalt production installation 2 equipped with a first drying drum 4 and a second drying drum 40 includes for example a pre-heated gas supply line 24 equipped with a heat exchanger 25 arranged for heat exchange between feed gases circulating in the supply line 24 and hot gases exiting the first drying drum 4 and / or the second drying drum 40, and configured to inject the pre-heated feed gases into the electric heating device 6, for example at the inlet of the ventilation device 10 and / or into the piping device 12 of the electric heating device 6, downstream of the ventilation device 10.

[0115] On the Figure 5 A preheated gas supply line 24 feeds the electric heating device 6 of the first drum 4 and the electric heating device 42 of the second drum 40. On the Figures 6 And 7, a 24 pre-heated gas supply line feeds the electric heating device 6 of the first drum 4.

[0116] Optionally, the asphalt production plant 2 includes one or more gas recycling fluid lines 23 each configured to recycle unfiltered hot gases and / or filtered hot gases at the inlet of the first drying drum 4 and / or to recycle unfiltered hot gases / or filtered hot gases at the inlet of the second drying drum 40.

[0117] In particular, the asphalt production plant 2 includes, for example, a gas recycling fluid line 23 configured to recycle filtered hot gases from the outlet of the second drying drum 40 to the inlet of the second drying drum 40 or, as illustrated in the Figure 7 , in the gas generator 44. The first variant is particularly suitable when the asphalt production plant 2 is equipped with a burner 30 arranged in the second drying drum 40.

[0118] Optionally, the electric gas heating device 6 supplying the first drying drum 4 is equipped with a thermal energy storage device 32, for example in a manner analogous to that illustrated in the Figures 3 And 4 .

[0119] The invention is not limited to the embodiments and variants disclosed above, other embodiments and variants being conceivable.

[0120] In the case of an asphalt production plant comprising a first drying drum 4 and a second drying drum 40, it is possible for example to supply the first drying drum 4 and the second drying drum 40 with hot gases produced by the same common electric gas heating device 6, optionally equipped with a thermal energy storage device 32.

[0121] It is also possible to supply the first drying drum 4 and the second drying drum 40 with hot gases produced by separate electric heating devices 6, each dedicated to a respective drum, but associated with a common thermal energy storage device 32 for thermal energy storage, for example, when electricity produced from renewable energy is available.

[0122] It is possible to combine the different examples of implementation and variant mentioned, in particular those illustrated on the Figures 1 à 7 .

[0123] For example, it is possible to combine the example of implementation illustrated on the Figure 1 with one of the examples of implementation illustrated on the Figures 3 And 4 , to provide two electric heating devices 6 supplying hot gases in parallel to the same drying drum, one of the two electric heating devices 6 being without a thermal energy storage device 32, the other of the two electric heating devices 6 being equipped with a thermal energy storage device 32, in which storage chamber 34 is fluidly connected to the piping device 12 in series (as on the Figure 3 ) or in parallel (as on the Figure 4 ).

[0124] This can be done for an asphalt production plant 2 comprising a single drying drum (as in Figure 1) or two drying drums (as in the Figure 5 ), the asphalt production installation 2 comprising two first electric heating devices 6 to supply the first drum 4, one of the two being equipped with a thermal energy storage device 32, and / or two second electric heating devices 42 to supply the second drum 40, one of the two being equipped with a thermal energy storage device 32.

[0125] It is also possible to plan for an asphalt production plant including two drying drums (as on the Figure 5 ), each supplied with hot gases by an electric heating device, the two electric heating devices sharing a common thermal energy storage device 32.

[0126] As illustrated on the Figures 8 And 9 It is possible to combine the Figure 2 with one of the examples of implementation illustrated on the Figures 3 And 4, to provide a drying drum 4 equipped with an electric heating device 6 to supply the drying drum 4 with hot gas, the electric heating device 6 comprising a thermal energy storage device 32 configured to temporarily store thermal energy produced by the electric heating device 6, in particular by the heating elements 8, and then release it later, and, furthermore, a combustion heating device 28 comprising a burner 30 to generate hot gases supplying the drying drum 4, by combustion of a fuel.

[0127] In examples, as illustrated on the Figures 8 And 9 , the asphalt production plant 2 is arranged so that the hot gases generated by the electric heating device 6 and the hot gases generated by the combustion heating device 28 feed the same first section T1 of the drying drum 4.

[0128] In examples, hot gases are generated by the electric heating device 6 out of the drying drum 4 and brought into the first section T1 of the drying drum 4.

[0129] In some examples, the combustion heating device 28 is arranged to generate a flame F in the first section T1 of the drying drum 4. In other examples, the combustion heating device 28 is arranged to generate hot gases in a hot gas generator having a combustion chamber separate from the drying drum 4 and connected to the drying drum 4 to bring the hot gases into the first section T1 of the drying drum 4.

[0130] In examples, as illustrated on the Figures 8 And 9The first section T1 is a downstream section of the drying drum 4, considering the direction of movement of the aggregates G and / or the asphalt aggregates AE in the drying drum 4. The downstream section is adjacent to the lowered end 4B. In such examples, the drying drum 4 operates, for example, in counter-current flow (i.e., with the aggregates G and / or the asphalt aggregates AE circulating in opposite directions, on the one hand, and the hot gases on the other).

[0131] In other examples, the first section T1 is an upstream section of the drying drum 4, considering the direction of movement of the aggregates G and / or the asphalt aggregates AE in the drying drum 4. The upstream section is adjacent to the raised end 4A. In such examples, the drying drum 4 operates, for example, in parallel flow (i.e., with the aggregates G and / or the asphalt aggregates AE circulating on the one hand, and the hot gases on the other, in the same direction).

[0132] In other examples, as illustrated on the Figures 10 And 11 , the asphalt production plant 2 is arranged so that the hot gases generated by the electric heating device 6 and the hot gases generated by the combustion heating device 28 feed respectively a first section T1 and a second section T2 distinct from the drying drum 4, offset axially along the drying drum 4, in particular a first section T1 and a second section T2 distinct from an upstream section and a downstream section.

[0133] In examples, hot gases are generated by the electric heating device 6 out of the drying drum 4 and brought into the first section T1 of the drying drum 4.

[0134] In some examples, the combustion heating device 28 is arranged to generate a flame F in the second section T2 of the drying drum 4. In other examples, the combustion heating device 28 is arranged to generate hot gases in a hot gas generator having a combustion chamber separate from the drying drum 4 and connected to the drying drum 4 to bring the hot gases into the second section T2 of the drying drum 4.

[0135] In examples, as illustrated on the Figures 10 And 11 , the first section T1 is the downstream section and the second section T2 is the upstream section, considering the direction of movement of the aggregates G and / or the asphalt aggregates AE in the drying drum 4. In such examples, the drying drum 4 operates for example in counter-current.

[0136] In other examples, the first section T1 is the upstream section and the second section T2 is a downstream section, considering the direction of movement of the aggregates G and / or the asphalt aggregates AE in the drying drum 4. In such examples, the drying drum 4 operates, for example, in parallel streams.

[0137] Preferably, in examples, the gases flow in the drying drum 4 from the first section T1 to the second section T2.

[0138] The hot gases produced by the electric heating device 6 are introduced into the first section T1 without introducing the hot gases generated by the combustion device 28 into the first section T1, then the hot gases generated by the combustion device 28 are added to the hot gases generated by the electric heating device 6 in the second section T2.

[0139] Advantageously, as illustrated on the Figures 10 And 11, the drying drum 4 is equipped with a recycling ring 52 allowing a material, in particular at least a fraction of the AE asphalt aggregates, to be introduced into an intermediate section T3 of the drying drum 4.

[0140] The intermediate section T3 is located axially along the drum 4 between the upstream section and the front section of the drying drum 4.

[0141] The material introduced into the intermediate section T3 flows towards the downstream section, considering the direction of flow of aggregates in drum 4, without passing through the upstream section.

[0142] In particular, when flame F is generated in the second section T2, which is the upstream section, asphalt aggregates AE introduced into the intermediate section T3 via the recycling ring 52 flow towards the second section T1, which is the downstream section, without being subjected to the high heat of flame F. They are subjected only to the hot gases generated by the electric heating device 6, and in particular by the heat storage device 32. This prevents overheating of the asphalt aggregates AE which already contain bitumen and binder.

[0143] Preferably, the aggregates G are introduced into the second section T2 and are thus heated by the flame F generated by the combustion device 28 in the second section T2. ​​The aggregates G can therefore be efficiently heated in the second section T2 and then mixed with the asphalt aggregates AE introduced via the recycling ring 52 into the first section T1, being heated in the first section T1 by the hot gases generated by the electric heating device 6, in particular by the heat storage device 32.

[0144] As illustrated on the Figures 10 And 11 , it is possible to introduce AE asphalt aggregates into the upstream section of the drying drum 4, in particular into the second section T2 defining the upstream section.

[0145] As illustrated on the Figures 10 And 11, it is possible to introduce a fraction of the AE asphalt aggregates into the upstream section of the drying drum 4, in particular into the second section T2 defining the upstream section, and a fraction of the AE asphalt aggregates into the intermediate section T3, via the recycling ring 52.

[0146] It is possible to include a recycling ring 52 in the various examples and variants, particularly those illustrated on the Figures 1 à 10 .

[0147] The recycling ring 52 is particularly advantageous for the differentiated heating of aggregates G and at least a fraction of the asphalt pavement aggregates AE, when the flame F is generated in the second section T2 defining the upstream section, the hot gases generated by the electric heating device 6, in particular by the heat storage device 32, supplying the first section T1, as illustrated in the Figures 10 And 11 .

[0148] A recycling ring 52 can be advantageous in other examples and variants. It is possible to provide a recycling ring 52 on the drying drum(s) 4, 40 in the various examples and variants described, in particular those described with reference to the Figures 1 à 11 .

[0149] The examples and variants with a drying drum 4 equipped with an electric heating device 6, including a heat storage device 32, and a combustion heating device 28 are applicable in asphalt production plants comprising one drying drum 4 or two drying drums 4, 40, as in the examples illustrated on the Figures 5 , 6 And 7 .

[0150] In examples with a thermal energy storage device 32, the storage material 36 includes, for example, a refractory material. The storage material 36 includes, for example, refractory bricks. Preferably, the refractory bricks are formed and / or stacked to define gas circulation spaces within the stack. This facilitates heat exchange between the gases and the refractory bricks. Alternatively, the storage material 36 includes, for example, aggregates, stones, and / or cast iron.

[0151] In all cases, preferably, the thermal energy storage device 32 is sized so that, when the maximum thermal energy storage capacity of the storage material 36 is reached, the thermal energy storage device 32 is capable of supplying a thermal power equal to or greater than 1 megawatt (MW) and / or a thermal power equal to or less than 20 MW, for example for an operating time equal to or greater than 2 hours (h) and / or equal to or less than 10h.

[0152] This allows for alternative operation of the asphalt production plant 2, for example to produce thermal energy and store it during a thermal energy storage phase without drying, then heat the gases only using the thermal energy storage device 32, without using the electric heating device 6, during a drying phase.

[0153] Preferably, the thermal energy storage device 32 is sized to store thermal energy equal to or greater than 2 megawatt-hours (MWh) and / or equal to or less than 200 MWh.

[0154] Preferably, the storage material 36 is designed to withstand a temperature equal to or greater than 600°C.

[0155] THE Figures 12 And 13 illustrate an electric heating device 6 comprising heating elements 8, a piping device 12, having an inlet 12A and an outlet 12B, and a thermal energy storage device 32, having a storage chamber 34 into which a storage material 36 is received.

[0156] The inlet 12A is intended to receive gases to be heated, for example gases from a recycling line 23 and / or a supply line 24. The outlet 12B is fluidly connected to the drying drum 4 to supply the drying drum 4 with hot gases.

[0157] The storage chamber 34 is located in series between the inlet 12A and the outlet 12B so as to allow the gas to flow from the inlet 12A to the outlet 12B through the storage chamber 34.

[0158] The storage enclosure 34 has a first end 34A fluidically connected to the inlet 12A via an inlet conduit 12D and a second end 34B fluidly connected to the outlet 12B via an outlet conduit 12E.

[0159] The piping device 12 has a thermal energy storage configuration ( Figure 12 ) in which the gases circulate in a closed loop, flowing through the storage vessel 34 in a first direction of circulation, the gases passing through the heating elements 8 and then the storage material 36. This allows the gas to be heated by the heating elements 8 and then the heat to be stored in the storage material 36, which is heated progressively. Preferably, in the thermal energy storage configuration ( Figure 12 ), input 12A and output 12B are closed.

[0160] The piping system 12 has a heating configuration with the release of previously stored thermal energy ( Figure 13 ), in which the gases flow from inlet 12A to outlet 12B through the storage chamber 34 in a second direction of flow opposite to the first direction of flow, passing through the storage material 36. The gases are heated by the storage material 36 as they pass through the storage chamber 34. The storage material 36 cools gradually. In the heating configuration ( Figure 13 ), input 12A and output 12B are open.

[0161] Preferably, the heating elements 8 are arranged so that in heating configuration, the gases flow from inlet 12A to outlet 12B through at least part of the heating elements 8. This allows the gases to be heated using the storage material 36 and the heating elements 8.

[0162] In this case, advantageously, at least part of the heating elements 8 are arranged so that the gases flow from the inlet 12A to the outlet 12B via the storage material 36 and then the heating elements 8. This allows the heating element 8 to be operated to increase the temperature of the gases previously heated by the storage material 36.

[0163] Installation 2 includes a ventilation device 10 configured to circulate gases through the storage enclosure 34 selectively in the first direction of circulation or in the second direction of circulation.

[0164] The ventilation device 10 is, for example, a reversible fan, i.e., a fan whose rotor can rotate in either direction. Alternatively, the ventilation device 10 comprises a fan and an adjustable direction control system to direct the outlet flow in one direction or the opposite direction.

[0165] The ventilation device 10 is for example disposed in the inlet duct 12D connecting the inlet 12A to the first end 34A of the storage enclosure 34.

[0166] In examples, the piping device 12 includes a recirculation conduit 12F fluidically connected to the storage enclosure 34 to form a closed loop circuit for implementing the thermal energy storage configuration.

[0167] The recirculation duct 12F has one end fluidly connected to the first end 34A of the storage enclosure 34 and a second end fluidly connected to the second end 34B of the storage enclosure 34.

[0168] The recirculation duct 12F, for example, has one end connected to the inlet duct 12D and a second end connected to the outlet duct 12E.

[0169] The recirculation duct 12F is for example connected to the inlet duct 12D, between the inlet 12A and the ventilation device 10.

[0170] The heating elements 8 are arranged in the closed loop circuit defined by the piping device 12 in thermal energy storage configuration.

[0171] In examples, and as illustrated on the Figures 12 And 13 , heating elements 8 are arranged in the outlet duct 12E connecting the storage enclosure 34 to the outlet 12B and / or in the storage enclosure 34 downstream of the storage material in the second direction of flow, in heating configuration.

[0172] Such heating elements 8 make it possible to heat the gases downstream of the storage material 36 in the storage configuration and to increase the temperature of the gases exiting the storage enclosure 34 in the heating configuration.

[0173] As an optional addition or alternative, heating elements 8 are arranged in the storage enclosure 34, without being located downstream of the storage material in the second direction of circulation in heating configuration and / or heating elements 8 are arranged in the recirculation duct 12F.

[0174] Such heating elements 8 allow the gases upstream of the storage material to be heated in the thermal energy storage configuration but do not allow the temperature of the gases exiting the storage enclosure 34 to be increased in the heating configuration.

[0175] The piping device 12 includes a valve system 50 configured to control the flow of gases in the piping device 12, in particular to implement the storage configuration and the heating configuration.

[0176] The valve system 50 includes, for example, an inlet valve 50A disposed at inlet 12A to selectively open or close inlet 12A, an outlet valve 50B to selectively open or close outlet 12B and, optionally, a recirculation valve to selectively allow or block the flow of gases in the recirculation duct 12D.

[0177] In examples, and as illustrated on the Figures 12 And 13 , the 50A inlet valve also acts as a recirculation valve, being configured to selectively close the 12A inlet and open the 12D recirculation duct in storage configuration ( Figure 12 ) or open inlet 12A and close recirculation duct 12D in heating configuration ( Figure 13 ).

[0178] In storage configuration, the inlet valve 50A closes the inlet 12A, the outlet valve 50B closes the outlet 12B and the recirculation valve (here the inlet valve 50A) closes the recirculation duct 12D. The storage enclosure 34 is connected to the recirculation duct 12D by forming a closed loop circuit.

[0179] In heating configuration, the inlet valve 50A leaves the inlet 12A open, the outlet valve 50B leaves the outlet 12B open and the recirculation valve (here the inlet valve 50A) closes the recirculation duct 48. The gases flow from the inlet 12A to the outlet 12B through the piping duct 12C, circulating in the storage chamber 34, via the storage material 36, and, possibly, the heating elements 8.

[0180] Advantageously, in examples in which heating elements 8 are arranged in a recirculation duct 12F, the electric heating device 6 includes a direct heating mode in which the gases flow from the inlet 12A to the outlet 12B via the recirculation duct 12F, bypassing the storage enclosure 34 and being heated by heating elements 8 arranged in the recirculation duct 12.

[0181] In such examples, the 50 valve system is suitable for implementing such a configuration. For this, the 50A inlet valve is, for example, a three-way valve allowing selective connection of the inlet 12A to the inlet duct 12D in a heating configuration with thermal energy recovery, connection of the inlet 12A to the recirculation duct 12F in a direct heating configuration, or connection of the inlet duct 12D to the recirculation duct in thermal energy storage mode.

[0182] The electric heating device 6 includes an electrical control unit 14 configured to control the operation of the electric heating device 6, in particular to control the supply of electricity to the heating elements 8 by the power source 26, the ventilation device 10 and the circulation control device 50.

[0183] Preferably, the storage chamber 34 is arranged so that the gases flow vertically within the storage chamber 34 and through the storage material 36. This allows the storage material 26 to be heated gradually from top to bottom or bottom to top, and then the heat to be recovered gradually, respectively from bottom to top or top to bottom. On the Figures 12 And 13The storage material has two zones separated by a continuous line, illustrating the hot zone (top), the cold zone (bottom) and the separation between the two (the continuous line).

[0184] During storage, once the gases are as hot at the inlet of the storage material as at the outlet of the storage material 36 (considering the first direction of flow), this means that the storage capacity is reached.

[0185] During heating, once the gases are as cold at the inlet of the storage material as at the outlet of the storage material 36 (considering the second direction of circulation), this means that all the available thermal energy has been recovered.

[0186] Preferably, the storage enclosure 34 is arranged so that the gases flow from top to bottom in the first direction of flow, i.e. in storage configuration ( Figure 12 ), and from bottom to top in heating configuration ( Figure 13 ).

[0187] The heating device 6 as illustrated on the Figures 12 And 13 is usable in all the examples and variants described above, in particular the examples and variants of Figures 1 à 11 , in particular equipped with 4, 40 drying drums with or without recycling ring for the introduction of AE asphalt aggregates into an intermediate section T3.

[0188] The asphalt production facilities are adapted for the implementation of an asphalt production process which includes the drying of aggregates G and / or asphalt aggregates AE in a rotating drum dryer 4 supplied with hot gases by an electric heating device 2.

[0189] The process includes drying aggregates G and / or asphalt aggregates AE in a drum dryer 4, the aggregates G and / or asphalt aggregates AE being heated by hot gases produced at least in part by an electric gas heating device 6.

[0190] The process preferably includes collecting and filtering the hot gases exiting the drying drum 4 in a gas treatment device 16.

[0191] Advantageously, the process includes recycling unfiltered hot gases and / or filtered hot gases exiting the dryer drum 4 into the inlet of the dryer drum 4, in particular into the inlet of the electric heating device 2.

[0192] The process optionally includes drying aggregates G and / or asphalt aggregates AE in the drying drum 4 which is a first drying drum 4, and drying aggregates G and / or asphalt aggregates AE in a second drying drum 4 supplied with hot gases by the electric gas heating device 6 supplying the first drying drum 4 and / or an electric gas heating device 6 dedicated to the second drying drum 40 and / or a combustion heating device.

[0193] The use of an electric heating device for the production of hot gas to feed a drying drum in an asphalt production plant helps to limit the environmental impact of asphalt production by allowing the use of electrical energy produced from renewable energy sources (wind, photovoltaic, solar thermal, concentrated solar, hydroelectric...).

[0194] The inclusion of a thermal energy storage system allows for the generation and storage of heat while renewable electricity is available, for later use. This maximizes the use of renewable energy and further reduces the environmental impact of asphalt production.

[0195] Combining an electric heating system with a thermal energy storage unit and a combustion heating system allows for the use of electrical energy during periods of surplus production relative to current needs, storing it as thermal energy. This enables the consumption of excess electrical energy and provides access to electricity at a lower cost.

[0196] It is possible to use decarbonized or low-carbon electricity produced during a period of overproduction. This limits the use of fossil fuels for the production of asphalt, particularly road asphalt.

[0197] Thermal energy, for example, is stored for a period of time for later use over another period of time. Thermal energy is stored one day for use the following day.

[0198] Storing energy in the form of heat and subsequently reusing it as heat is more efficient than storing it in the form of electrical energy. Il It also avoids the need for electric batteries.

[0199] Recycling hot gas at the inlet of the drying drum further limits the energy consumption of the asphalt production plant.

Claims

1. Asphalt production installation comprising a rotating drying drum (4) for receiving aggregates and / or asphalt aggregates for heating by circulation of hot gases in the rotating drying drum (4), and an electric gas heating device (6) configured to heat gases using electrical energy to obtain hot gases and supply the drying drum (4) with these hot gases.

2. Asphalt production plant according to claim 1, wherein the gas heating device (6) includes a ventilation device (10) for forcing the circulation of gases in the electric heating device (6) and in the drying drum (4).

3. Asphalt production plant according to claim 1 or claim 2, wherein the gas heating device (6) comprises heating elements (8) arranged in a piping device (12) fluidly connected to the drying drum (4).

4. Asphalt production plant according to any one of the preceding claims, wherein the electric heating device (6) includes a thermal energy storage device (32) configured to store thermal energy produced by the electric heating device (6) and subsequently release it to gases to produce hot gases.

5. Asphalt production plant according to claim 4, wherein the thermal energy storage device (32) comprises at least one storage chamber (34) inside which is arranged a thermal energy storage material (36).

6. Asphalt production plant according to claim 5, wherein the thermal energy storage material (36) is a refractory material.

7. Asphalt production installation according to claim 5 or 6 dependent on claim 3, in which a storage chamber (34) is arranged in series in the gas piping device (12) fluidly connected to the drying drum (4).

8. Asphalt production plant according to claim 7, wherein heating elements (8) are arranged in the storage enclosure (34) or fluidically upstream of the storage enclosure (34).

9. Asphalt production plant according to any one of claims 5 to 8 dependent on claim 3, wherein a storage enclosure (34) is fluidly connected in parallel to a heating section (12C) of the piping device (12) which is fluidly connected to the drying drum (4), the heating section (12C) receiving heating elements (8).

10. Asphalt production plant according to claim 5 to 9 dependent on claim 3, wherein the piping device (12) has a storage configuration in which the gases circulate in a closed loop by circulating in the storage enclosure (34) in a first direction of circulation, and a heating configuration in which the gases circulate from an inlet (12A) to an outlet (12B) of the piping device (12) by passing through the storage enclosure (34) in a second direction of circulation opposite to the first direction of circulation.

11. Asphalt production plant according to claim 10, wherein the piping device (12) has an inlet conduit (12D) connecting the inlet (12A) to a first end (34A) of the storage enclosure (14), an outlet conduit (12E) connecting the outlet (12B) to a second end (34B) of the storage enclosure (14) and a recirculation conduit (12F) connected to the inlet conduit (12D) and the outlet conduit (12E) to form the closed loop circuit.

12. Asphalt production plant according to any one of the preceding claims, comprising a combustion heating device (28) including a burner (30) disposed in the drying drum (4) to generate hot gases in the drying drum (4) or in a hot gas generator (44) separate from the drying drum (4) and fluidly connected to the drying drum (4) to supply the drying drum (4).

13. A plant for producing asphalt according to any one of the preceding claims, comprising a gas treatment device (16) configured for collecting hot gases at the outlet of the drying drum (4) and filtering the collected hot gases, and one or more fluidic recycling lines (23) each configured to take unfiltered hot gases and / or filtered hot gases and reinject them upstream of the drying drum (4), preferably upstream of the electric gas heating device (6) or into the electric gas heating device (6), in particular upstream of electric heating elements (8) of the electric gas heating device (6) and / or upstream and / or downstream of a ventilation device (10) of the electric gas heating device (6).

14. Asphalt production plant according to any one of the preceding claims, configured to supply the electric heating device (6) with hot gases exiting the drying drum (4) and / or with fresh gases preheated by heat exchange with the hot gases exiting the drying drum (4).

15. Asphalt production plant according to any one of the preceding claims, wherein the drying drum (4) is a first drying drum (4), the asphalt production plant comprising a second drying drum (40) separate from the first drying drum, the asphalt production plant being configured to supply the second drying drum (40) with hot gases produced by the gas heating device (6) supplying the first drying drum and / or by another electric gas heating device (42) and / or by a combustion heating device (28) comprising a burner (30) disposed in the second drying drum (42) and / or in a hot gas generator (44) separate from the second drying drum (42) and fluidly connected to the second drying drum (42) to supply the second drying drum (42) with hot gases.

16. Asphalt production plant according to claim 15, comprising a first electric gas heating device (6) for supplying the first drying drum (4) with hot gas and a second electric gas heating device (42) for supplying the second drum (40) with hot gas, the first gas heating device (6) being equipped with a first thermal energy storage device (32) configured to store thermal energy produced by the first electric heating device (6) and subsequently release it to gases circulating via the first electric heating device (6) and / or the second gas heating device (42) being equipped with a second thermal energy storage device (32) configured to store thermal energy produced by the second electric heating device (42) and subsequently release it to gases circulating via the second electric heating device (42) and / or thefirst gas heating device (6) and second gas heating device (42) sharing a common thermal energy storage device (32) configured to store thermal energy produced by the first electric heating device (6) and / or the second gas heating device (42) and subsequently return it to gases circulating through the first electric heating device (6) and / or to gases circulating through the second gas heating device (42).

17. Asphalt production plant according to any one of the preceding claims, comprising a recycling ring for the introduction of a material, in particular at least a fraction of the asphalt aggregates (AE) into an intermediate section (T3) of the drying drum (4) 18. A process for producing asphalt mixtures comprising heating asphalt aggregates and / or granules in one or more rotating drying drums by circulating hot gases in each drying drum, the process comprising heating gases using one or more electric gas heating devices each configured to produce hot gases using electrical energy to obtain hot gases.

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