AU2014338686B2

AU2014338686B2 - System for managing logistics flows in an electrolysis plant, aluminium smelter comprising the system, vehicle for using the system, and method for introducing said system into a pre-existing electrolysis plant

Info

Publication number: AU2014338686B2
Application number: AU2014338686A
Authority: AU
Inventors: Christophe BAYARD; Stephane Prodent; Gabriel Ruget
Original assignee: Rio Tinto Alcan International Ltd
Current assignee: Rio Tinto Alcan International Ltd
Priority date: 2013-10-25
Filing date: 2014-10-23
Publication date: 2019-12-19
Anticipated expiration: 2034-10-23
Also published as: FR3012389A1; WO2015059557A1; RU2678763C2; EP3061048B1; FR3012389B1; EP3061048A1; RU2016119954A3; CN105874482B; EP3061048A4; RU2016119954A; CA2926896C; CN105874482A; NZ718758A; CA2926896A1; AU2014338686A1

Abstract

The invention relates to a system (1) comprising a storage zone (2) for storing new anode assemblies (3), a treatment zone (4) for treating used anode assemblies (5), a production zone (6) comprising a plurality of electrolytic cells for the production of liquid metal by electrolysis, and a fleet of transport vehicles (50) for transporting new anode assemblies (3) from the storage zone (2) to the production zone (6) and used anode assemblies (5) from the production zone (6) to the treatment zone (4), in which the transport vehicles (50) are designed such that they can only transport a single anode assembly (3, 5) at a time.

Description

SYSTEM FOR MANAGING LOGISTICS FLOWS IN AN ELECTROLYSIS PLANT,

ALUMINUM SMELTER COMPRISING THE SYSTEM, VEHICLE FOR USING THE SYSTEM

AND METHOD FOR INTRODUCING SAID SYSTEM INTO A PRE-EXISTING

ELECTROLYSIS PLANT

TECHNICAL FIELD

The present invention relates to a system for managing logistics flows in an electrolysis plant, an aluminum smelter comprising this system, a transport vehicle for implementing this system, and a method of setting up this system in an existing electrolysis plant.

BACKGROUND

Traditionally, an electrolysis plant such as an aluminum smelter includes a building housing an electrolysis hall, in which are aligned hundreds of electrolytic cells for the production of aluminum by electrolysis according to the Hall-Heroult process.

For this purpose, electrolysis cells 100 such as those shown in figure 1, conventionally comprise a steel pot shell 102 within which is arranged a coating of refractory materials, a cathode 104 made of carbonaceous material, through which pass the cathode conductors for collecting the electrolysis current at cathode 104 to route it to the cathode outputs passing through the bottom or sides of the pot shell 102, connecting conductors extending substantially horizontally to the next cell from the cathode outputs, an electrolytic bath 106 in which alumina is dissolved, at least one anode assembly comprising at least one anode 110 immersed in this electrolytic bath and an anode rod 108 sealed in the anode 110, an anode frame 112 from which is suspended the anode assembly via the anode rod, and rising conductors of the electrolysis current, extending upwards and connected to the connecting conductors of the previous electrolytic cell 100 to route the electrolysis current from the cathode outputs to the anode frame and to the anode assembly and the anode of the next cell. The anodes are more particularly of the pre-baked anode type with prebaked carbon blocks, i.e. baked before they are placed in the electrolytic cell.

During the electrolysis reaction a layer of liquid aluminum 114 forms at the bottom of the electrolytic cell. The liquid aluminum so produced is regularly collected in casting containers also known as casting ladles. The liquid aluminum collected in this way is then transported to a foundry for processing.

The empty casting containers are transported from the foundry to the electrolysis hall. The aluminum from several electrolytic cells is typically collected in the same casting container. When this is full, it is transported from the electrolysis hall to the foundry.

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Transport of full or empty casting containers is conventionally performed by a first type of transport vehicle. This first type of vehicle conventionally includes, as seen in figure 2, a front tractive device 120 with a control cab 121, to which is attached an articulated trailer 122 capable of supporting a casting container 124 full of liquid aluminum collected from several electrolytic cells.

Furthermore, during the electrolysis reaction the anodes are progressively consumed, tt is therefore necessary to provide for the removal of worn anode assemblies and a regular supply to the electrolytic cells of new anode assemblies to replace the worn anode assemblies.

The new anode assemblies are usually stored in a storage area. The worn anode assemblies are stored in a processing area in which they can be recycled.

The transport of anode assemblies is provided by a second type of transportation vehicle, shown in figure 3, conventionally comprising a front tractive device 130 with control cab 131, and a trailer 132 coupled and articulated to the front tractive device. To minimize the number of trips, and reduce transportation costs per anode assembly, the trailer is designed to carry a plurality of anode assemblies 134. According to the example in figure 3, the trailer carries three anode assemblies at a time.

Full casting containers and batches of anode assemblies to be transported during the same trip are heavy loads weighing up to ten tons.

Current transport vehicles are therefore designed and sized to support and transport these heavy loads.

Current transport vehicles for casting containers or anode assemblies, whether laden or unladen, therefore have a large mass, are bulky, and have relatively low maneuverability.

Infrastructures, inside buildings and outside buildings, are designed to support these vehicles, and sized to allow them to maneuver.

This results in wide traffic lanes, generally greater than eight meters wide, allowing two vehicles to pass each other or one vehicle to make a U-turn. Bends have a large radius of curvature.

Moreover, the buildings inside which the vehicles have to run are consequently of large size. This has consequences for the equipment located inside the buildings. For example, traveling cranes extending over the width of the buildings are oversized, given their greater span.

Inside the electrolysis hall, a traffic lane, or operating aisle has to be kept at a floating potential in view of the presence of electrolytic cells nearby, carrying an electrolysis current of up to several hundred

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2014338686 03 Dec 2019 thousand amperes. This traffic lane is conventionally suspended and electrically insulated from the rest of the building. Given the mass of vehicles and their load, this implies major construction engineering work.

It should be noted, therefore, that current solutions for transporting loads in an electrolysis plant involve major infrastructure and civil engineering costs and require a large space that cannot be turned to advantage, for example, to increase the production capacity of the electrolysis plant.

Furthermore, it will be understood that the vehicles are specialized in the transport of a single type of load, either casting containers or anode assemblies. A third type of vehicle, such as an overhanging forklift truck with a counterweight may be provided to transport tools in the electrolysis hall. This plurality of separate vehicles involves high maintenance costs. This can also impact productivity because it is not possible to assign a momentarily unused vehicle to transporting a load, if the vehicle is specialized in the transport of a different type of load.

Furthermore, it should be noted that current transport vehicles are equipped with an internal combustion engine suitable for towing heavy loads. In addition to the detrimental effects in terms of emissions of carbon dioxide and other polluting gases inside the buildings through which they run, this requires the provision of an expensive and constraining fossil fuel supply. In addition, maintenance costs are high in view of the necessary presence of a transmission system.

In terms of productivity, it is noted that the service level of current vehicles, driven by operators, is entirely dependent on the availability of these operators.

Furthermore, current transport vehicles comprise governing means designed to limit their maximum speed. This advantageously helps to increase safety. However, productivity is affected to the extent that travel times are increased on portions where the risk of accident is small or non-existent, where vehicles could run at a speed higher than the maximum speed obtained by using governing means.

Finally, also in terms of productivity, it should be noted that the transport of several anode assemblies during the same trip sometimes makes it necessary to move new anode assemblies not immediately required for the operational needs of the electrolytic cells. These new anode assemblies are therefore placed near the electrolytic cells to be used later. They may temporarily be in the way between the time when a new anode assembly is placed there and when it is actually used to replace a worn anode assembly.

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A need of the present invention is a system for managing logistics flows in an electrolysis plant, an aluminum smelter comprising this system, a transport vehicle for the implementation of this system, and a method for setting up this system in an existing electrolysis plant.

tt is an object of the present invention to meet this need or to substantially overcome, or at least ameliorate, one or more disadvantages of existing arrangements.

SUMMARY

To this end, the present invention relates to a system for managing logistics flows in an electrolysis plant comprising new anode assemblies and worn anode assemblies, characterized in that the management system comprises:

- a storage area, for storing new anode assemblies,

- a processing area, for storing worn anode assemblies,

- a production area, comprising a plurality of electrolytic cells for the production of liquid metal by electrolysis, and

- a fleet of transport vehicles for conveying new anode assemblies from the storage area to the production area and worn anode assemblies from the production area to the processing area, wherein the transport vehicles are designed to be able to carry only one anode assembly at a time.

The management system according to the invention is therefore based on individualizing logistics flows, running counter to current trends which aim to increase the number of loads carried at each trip to minimize the number of trips and, as a result, logistics costs.

The individualization of logistics flows advantageously reduces the size of the vehicles, because the total load to be carried at each trip is less heavy.

This reduction in vehicle size means that the size of the traffic lanes, the costs of infrastructure and insulation of the floating potential aisles, and the outdoor spaces between buildings can be reduced.

The reduction in vehicle size also increases visibility. This is because staff present in the factory can see beyond the vehicles. This offers more safety.

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The reduction in the size of transport vehicle also reduces their mass. The performance required of engine design can be revised downward, so that savings can be made.

The individualization of logistics flows also helps to meet the exact needs of the production area in terms of new anode assemblies or the removal of worn anode assemblies after removing them from the electrolytic cell. In other words, individualizing logistics flows prevents new anode assemblies not immediately needed in the production area or worn anode assemblies awaiting disposal from being left in the production area, thereby causing temporary inconvenience and gas pollution.

The management system according to the invention may therefore potentially lead to substantial savings in terms of space and infrastructure.

Processing worn anode assemblies may consist in recycling them or storing them or disposal.

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According to one embodiment, the transport vehicles comprise one or more electric motors and a set of supercapacitors to power the electric motors, and the management system comprises at least one charging area provided with charging means to charge all the supercapacitors when a transport vehicle is located in the charging area.

Using an electric motor eliminates the need for fossil fuels, deemed expensive and polluting.

The use of an electric motor also allows savings in maintenance since the transport vehicles do not require a transmission system between the motor and the wheels. Transmission systems are particularly subject to strain on transport vehicles with internal combustion engines, and so require frequent maintenance.

The use of one or more supercapacitors further makes it possible to reduce the weight of the transport vehicle compared, for example, to the use of the equivalent in substantially heavier batteries. This weight reduction contributes to savings due to smaller infrastructure design and the space saving obtained, and to lower energy consumption by the transport vehicle.

The use of one or more supercapacitors also increases the lifetime of the vehicle because the supercapacitors have a substantially greater service life, about one thousand times greater, than that of batteries.

The supercapacitors of the supercapacitor assembly may advantageously be distributed uniformly throughout the transport vehicle. In other words, the supercapacitors may extend to all parts of the transport vehicle. The supercapacitors are not localized in a specific part of the transport vehicle. This makes it possible to balance the masses of the transport vehicle. In particular, the supercapacitors of the supercapacitor assembly may be arranged in the central portion and both side portions of the transport vehicle.

Advantageously, the charging means are remote recharging means.

Advantageously, said at least one charging area is placed on a route used by transport vehicles when carrying an anode assembly from the storage area to the production area and / or on a route used by transport vehicles when carrying an anode assembly from the production area to the processing area.

In addition, the charging area may be equipped with a charging system which does not require any physical contact with the transport vehicle in order to charge it. The latter is positioned for just a few tens of seconds above the charging system.

In this way, the supercapacitors are powered while the transport vehicles are working.

This avoids immobilizing vehicles outside vehicle workflow. This results in saving time, which improves productivity.

According to one embodiment, the management system further comprises a foundry area for solidifying the liquid metal, and a fleet of transport vehicles for conveying empty casting containers from the foundry area to the production area and casting containers containing liquid metal from the production area to the foundry area, wherein the casting containers are sized so as to be able to contain only the liquid metal cast in a single electrolytic cell from among the electrolytic cells of the production area when the casting cycle has a length d1 of about thirty hours, and wherein the transport vehicles are sized to be able to carry only one casting container at a time.

Casting cycle is taken to mean a cycle of emptying an electrolytic cell of a portion of the liquid metal it contains. The casting cycle time corresponds to the time period separating two successive collections of the liquid metal contained in a single electrolytic cell.

Alternatively, the management system further comprises a foundry area for solidifying the liquid metal, and a fleet of transport vehicles for conveying empty casting containers from the foundry area to the production area and casting containers containing liquid metal from the production area to the foundry area, wherein the casting containers are sized so as to be able to contain the liquid metal cast from several electrolytic cells from among the electrolytic cells of the production area when the casting cycle has a length d2 substantially less that a length d1 of about thirty hours, and wherein the transport vehicles are sized to be able to carry only one casting container at a time.

Therefore, unlike prior art, the casting container can contain only an amount of metal corresponding to the casting of a single electrolytic cell when the casting cycle has a conventional length of about thirty hours, or corresponding to the casting of several electrolytic cells, for example three electrolytic cells, when the casting cycle is short, for example of the order of ten hours.

The size and mass of the casting container, empty or full, are smaller, so that the dimensions and weight of transport vehicles designed to transport them are less than those of the vehicles of prior art. This results in significant savings in terms of indoor and outdoor infrastructure, better visibility for staff on foot, and greater flexibility.

In one embodiment, transport vehicles for conveying a single anode assembly at a time and transport vehicles for conveying a single casting container at a time are substantially identical, so that the fleets of transport vehicles can be considered as a single fleet of transport vehicles.

This makes it possible to use one standard type of transport vehicle to transport anode assemblies and casting containers. This provides economies of scale in view of the larger series produced.

It also results in greater flexibility: the vehicles are interchangeable. A vehicle used for the transportation of an anode assembly may be detached for the transportation of a casting container, and vice versa, to cope with an urgent need.

Standardizing transport vehicles also reduces maintenance costs, since the vehicle parts are the same.

For example, for an electrolysis plant of the aluminum smelter type, comprising 430 electrolytic cells through which a current of about 600 kilo amps passes, the management system may comprise about seven transport vehicles used to transport single anode assemblies and nine vehicles used to transport single casting containers.

According to one embodiment, the transport vehicles are automated, and the management system comprises a monitoring unit to monitor the movement of each transport vehicle with a view to conveying new anode assemblies from the storage area to the production area and worn anode assemblies from the production area to the processing area, and, if appropriate, with a view to conveying empty casting containers from the foundry area to the production area and casting containers containing liquid metal from the production area to the foundry area.

Automated transport vehicles can operate during operator-driver break periods or when they are changing shift, thereby increasing productivity.

In addition, automated transport vehicles provide greater traceability of loads carried.

Advantageously, the transport vehicles include automatic guiding means, designed to enable the transport vehicles to move independently in the electrolysis plant.

This feature is advantageous because it does not require infrastructure changes to guide the transport vehicles (e.g. by adding reflective tape on the floor).

In addition, this feature allows vehicles to be guided efficiently regardless of weather conditions, light conditions (day or night) without bothering about dust that might cover the ground, both indoors and outdoors.

According to one embodiment, the management system comprises at least one first traffic area and at least one second traffic area, in which the transport vehicles are designed to run, and means for limiting the speed of the transport vehicles associated with guiding means to automatically limit the speed of the transport vehicles running in said at least one first traffic area to a first predetermined speed V1 and the speed of the transport vehicles running in said at least one second traffic area to a predetermined second speed

V2 greater than the first speed V1.

This meets safety requirements by requiring vehicles to keep to a speed limit appropriate to the risks presented by the area in which they are running.

This also ensures that the transport vehicles run at the highest speed possible given the surrounding risks and constraints, to increase productivity.

Advantageously, the first traffic area comprises one or more areas from among the storage area, the processing area, the production area and, if appropriate, the foundry area, and the second traffic area is arranged outside of the storage area, the processing area, the production area and, if appropriate, the foundry area.

In this way, the transport vehicles run at low speeds inside buildings and in areas at risk, such as where personnel and equipment are concentrated, and travel at higher speeds outside of buildings and areas at risk .

According to another aspect of the invention, this relates to an aluminum smelter comprising a plurality of rectangular electrolytic cells for aluminum production and a system with the aforementioned features, the aluminum smelter further comprising one or more buildings, the building(s) containing said plurality of electrolytic cells, and at least one working aisle arranged within said building containing said plurality of electrolytic cells, the working aisle being designed for transport vehicles to supply said plurality of electrolytic cells with new anode assemblies or removing a worn anode assembly from said plurality of electrolytic cells, and wherein said at least one working aisle has a width less than or equal to one third, preferably less than or equal to a quarter of the length of said electrolytic cells.

The aluminum smelter may include several working aisles, each arranged within said building containing said plurality of electrolytic cells and each designed for the transport vehicles to supply said plurality of electrolytic cells with new anode assemblies or removing a worn anode assembly from said plurality of electrolytic tanks, and each working aisle may have a width of less than or equal to one third, preferably less than or equal to a quarter of the length of said electrolytic cells.

This substantial reduction in the width of the working aisles provides savings in infrastructure. The buildings are smaller, and therefore less expensive. Related savings are achieved because of the reduction in the dimensions of the buildings. This is because the service buildings related to the span of the pot tending machines are smaller and therefore less expensive, and the pot tending machines are lighter due to the smaller span and therefore also cheaper.

According to one embodiment, the aluminum smelter has at least one traffic lane for the movement of transport vehicles outside the building(s) of the aluminum smelter; said at least one traffic lane has a width less than 6.5 m, and preferably less than or equal to 6 m.

The aluminum smelter may include several traffic lanes for the movement of transport vehicles outside the building(s) of the aluminum smelter, each traffic lane having a width less than 6.5 m, and preferably less than or equal to 6 m.

Reducing the width of the working aisles and traffic lanes also saves a substantial amount of space. By way of example, a 30% reduction in the width of the working aisles (and the resulting reduction in the size of buildings) and traffic lanes gives a reduction of about 20% of the ground area taken up by the aluminum smelter. This works without reducing the number of electrolytic cells, so that the amount of aluminum produced per square meter increases substantially.

According to another aspect of the invention, it relates to a transport vehicle for implementing the system having the above characteristics, the transport vehicle comprising automatic guiding means to allow it to move independently, said transport vehicle being sized to carry only one anode assembly at a time.

In this way, the transport vehicle has relatively small dimensions compared with the dimensions of the vehicles of prior art.

This reduction in dimensions contributes to a reduction in the mass of the vehicle. This reduction in mass, as explained above, allows significant savings in infrastructure.

Moreover, the reduction in size offers enhanced visibility beyond the vehicle, which contributes to improved safety for personnel located nearby.

Automating the vehicle with automatic guiding means eliminates the need for a control station designed to accommodate a driver operator. This results in weight savings and enhanced visibility and a reduction in the cost of the vehicle in view of the absence of comfort and safety equipment required for a control cab.

Automating the vehicle also offers the possibility of transporting heavy loads round the clock without interruption, including without interruptions due to operator-driver breaks or shift changes, driving the vehicles in the state of art.

According to one embodiment, the vehicle comprises lifting means designed to lift a single anode assembly, and a plurality of wheels supporting the vehicle and arranged to form a polygon within which the lifting means extend.

In this way, the transported load is centralized as it is between the wheels supporting the vehicle. In other words, the vehicle has no overhang and no counterweight capable of substantially increasing its mass. The centralization of the load can therefore substantially reduce the vehicle mass.

According to one embodiment, the vehicle comprises a single anode assembly carried by the lifting means and the surface of the polygon formed by the arrangement of the wheels is substantially between 0.5 and 1.5 times an area projected in a substantially horizontal plane of the anode assembly.

According to one embodiment, the vehicle comprises a single anode assembly carried by the lifting means and the lifting means have an overall support surface, on which the single anode assembly is designed to rest, the overall support surface being between 1 and 1.5 times the area projected in a substantially horizontal plane of the anode assembly.

A single anode assembly can thereby be supported by the lifting means and the vehicle.

According to one embodiment, the vehicle comprises a single anode assembly carried by the lifting means and an area projected in a substantially horizontal plane of the transport vehicle is substantially less than or equal to triple, and preferably less than or equal to double the area projected in a substantially horizontal plane of the single anode assembly.

According to one embodiment, the transport vehicle comprises a U-shaped frame having a central portion and two substantially parallel side portions between which extend the lifting means, and the wheels are arranged under the side portions and under the central portion.

According to one embodiment, the transport vehicle comprises one or more electric motors and a set of supercapacitors to power the electric motor(s)

According to one embodiment, the transport vehicle comprises shielding means designed to protect the on-board electronics against the effects of a magnetic field.

According to one embodiment, the transport vehicle comprises a frame and at least one vehicle wheel is mobile relative to the frame about a substantially vertical axis of rotation.

In this way, the transport vehicle has a low turning radius. This increases its agility, especially for making U-turns practically on the spot.

According to one embodiment, the transport vehicle includes means designed to attach a tractor pallet, sized to carry a single casting container, to the transport vehicle .

In this way, the transport vehicle may either lift a single anode assembly or pull a single casting container. In other words, the transport vehicle is interchangeable, and therefore provides greater flexibility of use.

According to one embodiment, the transport vehicle comprises remote control means designed to control movement of the vehicle on the basis of signals emitted by remote control means designed to enable an operator to take control of the transport vehicle from a distance.

In this way, the transport vehicle can be remotely operated. This allows a user to remotely take control of the vehicle, for example to make it perform a difficult movement to avoid obstacles. To remotely control the vehicle, the user can use the images received from one or more cameras arranged on the vehicle and, where appropriate, in the electrolysis plant.

According to one embodiment, the transport vehicle has a mass less than or equal to five tonnes.

According to one advantageous embodiment, the transport vehicle comprises and supports a single anode assembly, and the weight of the transport vehicle is less than or equal to the weight of said anode assembly.

According to one embodiment, the vehicle has a maximum height less than or equal to 1200 mm.

According to one embodiment, the vehicle has a maximum width less than or equal to 2500 mm.

According to one embodiment, the vehicle has a maximum length less than or equal to 3800 mm.

Such a weight and such dimensions are not to be taken for granted, because the tendency to have one vehicle to carry anode assemblies simultaneously, or to transport a casting container containing the liquid metal collected from several electrolytic cells by the same vehicle necessarily leads one to consider vehicles of great weight and with large dimensions, suited to carrying such loads (the vehicle plus the load totaling more than thirty tons).

In yet another aspect, the present invention relates to a method for setting up a system having the above characteristics in an electrolysis plant comprising a first fleet of transport vehicles, sized for simultaneously transporting a plurality of anode assemblies, the method comprising a step of replacing said first fleet of vehicles by a second fleet of

2014338686 03 Dec 2019 transport vehicles, said second fleet of transport vehicles comprising at least one transport vehicle sized to be able to carry only one anode assembly at a time.

This will provide increased flexibility, safety and productivity in an existing electrolysis plant, by making it benefit from a flow of single loads. This is made feasible by automating vehicles; this operation does not require costly infrastructure changes.

Advantageously, all the transport vehicles of the second fleet of transport vehicles are sized so that they can carry only one anode assembly at a time.

According to one embodiment, the method comprises a step of marking out at least one first traffic area and at least one second traffic area in which the transport vehicles of said second fleet of transport vehicles are designed to run, a step of determining a first predetermined speed V1 corresponding to the maximum permissible speed of the transport vehicles of the second fleet in said at least one first traffic area, a step of determining a second predetermined speed V2 greater than the first speed V1 and corresponding to the maximum permitted speed of travel of the transport vehicles of the second fleet in said at least one second traffic area, and a step of setting up means for limiting the speed of the transport vehicles designed to limit the of speed of the transport vehicles running in said at least one first traffic area to the first predetermined speed V1, and the speed of transport vehicles running in said at least one second traffic area to the second predetermined speed V2 greater than the first speed VI.

This makes it possible to improve productivity by enabling vehicles to run at maximum speed traffic in the stretches where there is a low risk of collision (straight stretches outdoors), given the extra safety provided by vehicle automation (no driver fatigue or lapse of attention).

According to one embodiment, the method comprises a step of separating at least one traffic lane of the electrolysis plant into at least two distinct lanes.

In this way, an existing lane, initially dedicated exclusively to the movement of transport vehicles of the first fleet capable of carrying several anode assemblies simultaneously, can be separated into one lane for pedestrians and other lane for transport vehicles of the second fleet, so as to define a pedestrian flow and a vehicle flow for the same lane. This is made possible due to the reduction in size of the vehicles of the second fleet reduction made possible by the individualization of the load carried.

Other features and advantages will be clearly apparent from the following description of an embodiment of the invention provided by way of a non-limiting example with reference to the appended drawings, in which:

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BRIEF DESCRIPTION OF THE DRAWINGS

- figure 1 shows an electrolytic cell according to the state of the art.

- figure 2 shows a transport vehicle for a casting container according to the state of the art,

- figure 3 shows a transport vehicle for anode assemblies according to the state of the art,

- figure 4 is a schematic representation of a management system according to one embodiment of the invention,

- figures 5 and 6 are perspective views of a transport vehicle according to one embodiment of the invention, respectively carrying an anode assembly and a casting container,

- figures 7 and 8 are perspective views of a transport vehicle according to one embodiment of the invention, respectively with and without an anode assembly,

- figure 9 is a rear view of a transport vehicle according to one embodiment of the invention, carrying an anode assembly,

- figure 10 is a view showing a tractor pallet of a transport vehicle according to one embodiment of the invention,

- figure 11 is a comparative side view between an anode assembly transport vehicle according to prior art and a transport vehicle according to one embodiment of the invention,

- figure 12 is a comparative side view between a casting container transport vehicle according to prior art and a transport vehicle according to one embodiment of the invention,

- figure 13 shows a traffic lane in an electrolysis plant according to prior art,

- figure 14 shows a traffic lane in an aluminum smelter according to one embodiment of the invention,

- figure 15 is a cutaway drawing of a transport vehicle according to one embodiment of the invention.

DETAILED DESCRIPTION

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Figure 4 shows a system 1 for managing the logistics flows of an electrolysis plant comprising new anode assemblies 3 and worn anode assemblies 5, according to one embodiment of the invention.

The management system 1 comprises a storage area 2, for the storage of new anode assemblies, a processing area 4, for processing worn anode assemblies, and a

23952227 1 production area 6, comprising a plurality of rectangular electrolytic cells for the production of liquid metal by electrolysis.

The management system 1 also includes a fleet of transport vehicles 50 for conveying new anode assemblies from storage area 2 to production area 6 and worn anode assemblies from production area 6 to processing area 4.

It is important to note that the transport vehicles 50 are designed to carry a single anode assembly at a time. In other words, it is impossible for transport vehicles 50 to carry more than one anode assembly. Transport vehicles 50 are sized to carry a single anode assembly at a time.

The management system 1 according to the invention is therefore based on individualizing logistics flows, running counter to current trends which aim to increase the number of loads carried at each trip to minimize the number of trips and, as a result, logistics costs. The management system 1 according to the invention may therefore potentially lead to substantial savings in terms of space and infrastructure.

The management system 1 may also include a foundry area 8, for the solidification of the liquid metal, and a fleet of transport vehicles 50' for transporting empty casting containers 61 from foundry area 8 to production area 6 and casting containers 63 containing liquid metal from production area 6 to foundry area 8 . The casting containers are sized so that either they are able to contain only the liquid metal cast in a single electrolytic cell from the electrolytic cells in the production area 6 when the casting cycle has a length d1 of about thirty hours, or to contain the liquid metal cast from several electrolytic cells from the production area 6 when the casting cycle has a length d2 of substantially less than a length d1. Moreover, it should be noted that the transport vehicles 50' are sized so as to be able to carry only one casting container at a time.

As an illustration, length d1 corresponds to a conventional casting cycle time. Length d2 may be at least two times shorter than length d1, more preferably at least three times shorter. Length d2 may therefore be of the order of ten hours.

So, unlike prior art, the casting container can contain only an amount of metal corresponding to the casting of a single electrolytic cell when the casting cycle has a conventional length of about thirty hours, or corresponding to the casting of several electrolytic cells, for example three electrolytic cells, when the casting cycle is short, for example of the order of ten hours so that the size and mass of the casting container, empty or full, are smaller, and the size and mass of transport vehicles 50' designed to carry them are less than those of state of the art vehicles. This results in significant savings in terms of indoor and outdoor infrastructure, better visibility for staff on foot, and greater flexibility.

As can be seen in figures 5 and 6, transport vehicles 50 for conveying a single anode assembly at a time and transport vehicles 50’ for conveying a single casting container at a time are substantially identical, so that the fleets of transport vehicles can be considered as a single fleet of transport vehicles. Transport vehicles 50' may therefore comprise some or all of the features of vehicles 50 which will be described in more detail below.

The management system 1 may also comprise a manufacturing area 10, for the manufacture of new anode assemblies 3, and transport vehicles 50” for conveying a single new anode assembly 3 from the manufacturing area 10 to the storage area 2.

These transport vehicles 50” may advantageously be substantially similar to transport vehicles 50 for conveying new anode assemblies 3 from storage area 2 to production area 6 and worn anode assemblies 5 from production area 6 to processing area 4. Transport vehicles 50” may therefore comprise some or all of the features of vehicles 50 which will be described in more detail below.

The management system 1 may therefore include a single type of transport vehicle for transporting either a single anode assembly or a single, low capacity casting container, for example sized to hold up to 6 tonnes of liquid metal.

The management system 1 may include a first flow representing the transport of new anode assemblies 3 from storage area 2 to production area 6, a second flow representing the transport of worn anode assemblies 5 from production area 6 to processing area 4, a third flow representing the transport of casting containers 63 containing liquid metal from production area 6 to foundry area 8, a fourth flow representing the transport of empty casting containers 61 from foundry area 8 to production area 6, and a fifth flow corresponding to the transport of new anode assemblies 3 from manufacturing area 10 to storage area 2.

Transport vehicles 50, 50’, 50” are designed to run inside 12 and I or outside 14.

Storage area 2, processing area 4 and, if appropriate, manufacturing area 10 may be arranged within a given building.

Transport vehicles 50 advantageously comprise one or more electric motors 52 and a set of supercapacitors 54 to power electric motors 52, shown in the cutaway drawing in figure 15.

The management system 1 comprises at least one charging area 16 with means for recharging all the supercapacitors 54 when one of the transport vehicles 50 is located in the charging area 16.

The charging means may be charging means by induction. They may also be embedded under the roadway.

The charging area(s) 16 are advantageously arranged on a route taken by transport vehicles 50, 50’, 50” when transporting an anode assembly or a casting container according to the first flow and I or the second flow and I or the third flow and I or the fourth flow and I or the fifth flow.

Transport vehicles 50 are advantageously automated, and the management system 1 comprises a monitoring unit 20 to monitor the movement of each transport vehicle 50, for routing anode assemblies and casting containers according to the first, second, and, if appropriate, third, fourth and fifth flow.

Transport vehicles 50 include, for example, automatic guiding means, designed to enable transport vehicles 50 to move independently in the electrolysis plant.

In particular, the guiding means 50 allow each transport vehicle to geolocate itself, calculate a reference trajectory and elaborate control commands.

The guiding means may include, for example, a SLAM system 60 (Simultaneous Localisation And Mapping). In this way, the guiding means may include laser rangefinders, cameras, and a storage unit capable of storing a digitized map of the electrolysis plant and I or mapping routes as a database.

Transport vehicles 50 may have on-board communication means (not shown) to receive mission and movement orders from the monitoring unit 20 and I or send information on mission accomplishment, availability and I or real-time positioning and I or send and I or receive updates to route mapping and I or maps of the electrolysis plant.

The communication means may be based on wireless network technology such as 3G or WiFi.

Transport vehicles 50 may include means for obstacle detection (not shown) designed to prevent a collision with an obstacle (human or equipment). The obstacle detection means include, for example, safety lasers, capacitive sensors or cameras.

Transport vehicles 50 may include a LED (Light Emitting Diode) plate 56, for example, substantially semicircular on the outer front edge of the vehicle. This LED plate 50 reflects the position of an obstacle within a detection area covered by the obstacle detecting means. This allows the activation of a visual alarm informing that an obstacle has been detected.

Transport vehicles 50 may carry an on-board control system (not shown) for receiving information from the guiding means and actuating the operating components of the vehicle 50, to move it or lift a load. The control system is based on information provided by the guiding means to generate orders as to what path to follow taking into account the kinematics of the vehicle 50 and the type of load and the weight of the load carried. By way of example, the control system can achieve an anti -sway effect by integrating the oscillation phenomenon when transporting liquid metal.

Transport vehicles 50 may include signaling means such as flashing lights, an audible and I or visible warning device 58, to indicate their approach and their path to those present around. This contributes to greater safety.

Monitoring unit 20 is designed to coordinate the operation of transport vehicles 50, 50’, 50” according to the needs of the electrolysis plant.

Monitoring unit 20 may include a mission management module 22, for planning and scheduling the missions of transport vehicles from real-time data coming from related systems 24, for example wear of an anode, duration and frequency of casting cycles, stocks of raw materials, available places in the storage workshop, traveling crane operations under way or planned (changing the anode of cell x, metal casting in cell y). Mission orders generated in this way are then sent to the most appropriate transport vehicle 50, 50’, 50”, i.e. one that is the closest, for example, and quickly available in view of the mission to be performed. Mission management module 22 can be completed by an interface module 21 allowing an operator to interact with the management module 22.

A Man Machine interface can, for example, be designed to inform operators in the control room about the status of various equipment, their location and missions under way, upcoming maintenance operations, lane status (available or undergoing maintenance work), the history of activities over a specific period.

Monitoring unit 20 may include a computer and a computer program designed to manage logistics flows, for generating mission orders and movements, and telecommunication facilities, designed to convey these mission and movement orders to the transport vehicles.

Monitoring unit 20 may also include a route calculation module (not shown) for determining a route to be used by transport vehicles 50, 50’, 50” based on data such as the condition of lanes and / or information from a weather station.

Monitoring unit 20 may comprise remote control means (not shown), known to those skilled in the art, enabling a user to take control of one of the transport vehicles 50, 50’,

50”. Transport vehicles 50, 50’, 50” comprises radio control means (not shown), known to those skilled in the art, for receiving signals from the remote control means to permit remote control of transport vehicles 50, 50’, 50”.

Advantageously, the management system 1 comprises at least one first traffic area 12 and at least one second traffic area 14, in which the transport vehicles 50, 50’, 50” are designed to run, and means for limiting the speed of the transport vehicles associated with guiding means to automatically limit the speed of the transport vehicles running in the first traffic area 12 to a first predetermined speed V1 and the speed of the transport vehicles running in the second traffic area 14 to a predetermined second speed V2 greater than the first speed V1.

For purely illustrative purposes, the first speed V1 may be of the order of 5 km / h and the second speed V2 may be of the order of 25 to 30 km I h.

Advantageously, the first 12 traffic area comprises one or more areas from among the storage area 2, the processing area 4, the production area 6 and, if appropriate, the foundry area 8 and I or the manufacturing area 10, and the second 14 traffic area is arranged outside of the storage area 2, the processing area 4, the production area 6 and, if appropriate, the foundry area 8 and I or the manufacturing area 10.

According to another aspect of the invention, the latter relates to an aluminum smelter comprising a plurality of rectangular electrolytic cells for aluminum production and a management system 1 having the aforementioned characteristics, the aluminum smelter further comprising one or more working aisles for the movement of transport vehicles 50, 50’, 50” inside one or more buildings of the aluminum smelter in which the electrolytic cells are arranged, and in which or the working aisle(s) have a width lower than or equal to a third, and preferably to a quarter of the length of the electrolytic cells.

More particularly, the length of the electrolytic cells of an aluminum smelter, according to one aspect of the invention, in which an electrolysis current of about 600 kilo amps circulates is, for example, about 18 m, for a width of about 4.5 m of the circulation aisle.

The aluminum smelter may also include, outside of its building(s), one or more traffic lanes for the transport vehicles 50, 50’, 50” to run on outside, this (these) external traffic lane(s) advantageously having a width less than or equal to 6.5m, and preferably less than or equal to 6 m.

Figures 13 and 14 show respectively an outside traffic lane of a conventional prior art aluminum smelter (figure 13) and a traffic lane of an aluminum smelter according to the invention (figure 14). It is easy to see the difference in width: 8.8m for the lane in the conventional aluminum smelter and 6m for that of the aluminum smelter of the invention. The conventional aluminum smelter lane is sized to allow two conventional transport vehicles to pass each other, while the lane of the aluminum smelter according to the invention allows two transport vehicles 50 according to the invention to pass each other.

According to another aspect of the invention, this relates to a transport vehicle 50 designed to implement the management system 1 described above. Transport vehicle 50 includes automatic guiding means designed to allow it to move independently, like those previously described. Transport vehicles 50 is sized to carry only a single anode assembly at a time. In other words, transport vehicle 50 cannot carry more than one anode assembly at a time.

The transport vehicle 50 may, according to one embodiment of the invention, comprise lifting means designed to lift a single anode assembly and a plurality of wheels 62 supporting the vehicle and arranged to form a polygon 64 within which the lifting means substantially extend. The lifting means may, for example, include a lifting pallet 66 designed to support the single anode assembly. The lifting means may also comprise a fork, extending inside the U formed by the vehicle, and I or several L-shaped brackets 82 extending inside the U along the side portions 74 and I or the central portion 72 described below. The forks and I or brackets are designed to support the pallet. The lifting means may also include vertical movement means for the forks and I or the brackets. These movement means include, for example, a connecting rod / jack.

As shown in figure 7, vehicle 50 may comprise a single anode assembly 3,5 carried by the lifting means, and the surface of the polygon 64 formed by the arrangement of the wheels 62 is substantially between 0.5 and 1.5 times an area projected in a substantially horizontal plane of the anode assembly 3,5.

The vehicle may also comprise a single anode assembly 3,5 carried by the lifting means and the lifting means have an overall support surface, on which the single anode assembly 3,5 is designed to rest, the overall support surface being between 1 and 1.5 times the area projected in a substantially horizontal plane of the anode assembly 3,5.

Vehicle 50 may comprise a single anode assembly 3, 5 carried by the lifting means and an area projected in a substantially horizontal plane of the transport vehicle 50 is substantially less than or equal to triple, and preferably less than or equal to double the area projected in a substantially horizontal plane of the single anode assembly. In this way, the size and bulk of the vehicle is minimum in relation to the load transported.

As can be seen in figures 7 and 8 the transport vehicle 50 comprises a U-shaped frame 70 having a central portion 72 and two substantially parallel side portions 74 between which extend the lifting means, and the wheels 62 are arranged under the side portions 74 and under the central portion 72. The single-frame vehicle 50 can therefore move laden and unladen.

At least one of the wheels 62 of the vehicle 50, for example the front wheel or wheels 62 located beneath the central portion 72, is mobile relative to the frame 70 about a substantially vertical axis of rotation, as illustrated in figure 8. In this way, the transport vehicle has a low turning radius. This increases its agility, especially for making U-turns practically on the spot, as shown in figure 9.

The transport vehicle 50 may include means designed to attach a tractor pallet 76, sized to carry a single casting container, to the transport vehicle .

As illustrated in Figure 10, the attaching means comprise, for example, a pin 78, especially a beveled pin protruding from the tractor pallet 76, and a notch 80 formed in the transport vehicle 50, specifically formed in the lifting means, in particular in a bracket 82 of the lifting means designed to support a pallet to carry a single anode assembly, the notch 80 being shaped to receive the pin 78 when the tractor pallet 76 is attached to the transport vehicle 50 .

In this way, the supporting functions of the pallet receiving the anode assembly and that of attaching the tractor pallet supporting the casting container are formed by means of a single mechanical member, namely brackets with a notch, so that the size of the cargo area of the vehicle is limited, which helps advantageously to further restrict the size of the transport vehicle 50 .

The transport vehicle may include shielding means (not shown) to protect the electronics against the effects of a magnetic field. The shielding means comprise a metal casing, for example. The metal casing is designed to enclose any part of the transport vehicle 50 operation of which may be affected by the ambient magnetic field generated in particular by the circulation of an electrolysis current of several hundreds of thousands of amperes in the electrolytic cells.

Transport vehicle 50 may of course include some or all of the characteristics of the transport vehicles described above in reference to the management system 1.

In particular, transport vehicle 50 may comprise one or more electric motors 52 and a set of supercapacitors 54 to power the electric motor. For example, vehicle 50 is driven by inwheel motors powered by supercapacitors which are designed to be recharged by induction during a brief stop at a charging area 16.

Also, transport vehicle 50 may comprise remote control means designed to control movement of the vehicle on the basis of signals emitted by remote control means designed to enable an operator to take control of the transport vehicle 50 from a distance.

According to the embodiment of figures 11 and 12, vehicle 50 has a maximum height h less than or equal to 1200 mm, providing good visibility for staff on foot beyond the vehicle, a maximum width less than or equal to 2500 mm, and a maximum length L less than or equal to 3800 mm.

Transport vehicle 50 may have a mass less than or equal to five tonnes.

In particular, the mass of the transport vehicle is less than or equal to the mass of the single anode assembly it carries.

The mass and dimensions, substantially lower than those of conventional transport vehicles represented for purposes of comparison on the same scale as transport vehicle 50 in figures 11 and 12, make it possible in particular, as has been mentioned above, to reduce size and infrastructure costs, and improve safety by providing greater visibility.

In yet another aspect, the invention relates to a method for setting up the management system 1 described above in an electrolysis plant comprising a first fleet of transport vehicles, sized for simultaneously transporting a plurality of anode assemblies, the method comprising a step of replacing the first fleet of vehicles by a second fleet of transport vehicles, the second fleet of transport vehicles comprising at least one transport vehicle 50 sized to be able to carry only one anode assembly at a time.

Transport vehicles 50 of the second fleet may have some or all of the features described above with reference to transport vehicles 50 designed to implement the management system 1 according to the invention.

The method may comprise a step of marking out at least one first traffic area 12 and at least one second traffic area 14 in which the transport vehicles 50 of said second fleet of transport vehicles are designed to run, a step of determining a first predetermined speed V1 corresponding to the maximum permissible speed of the transport vehicles 50 of the second fleet in the first traffic area, a step of determining a second predetermined speed

V2 greater than the first speed V1 and corresponding to the maximum permitted speed of travel of the transport vehicles 50 of the second fleet in the second traffic area, and a step of setting up means for limiting the speed of the transport vehicles 50 designed to limit the of speed of the transport vehicles 50 running in the first traffic area 12 to the first predetermined speed V1, and the speed of transport vehicles 50 running in the second traffic area 14 to the second predetermined speed V2 greater than the first speed V1.

The first and second speeds V1 and V2 may, as described above, be of the order of 5 km I h and of the order of 25 to 30 km / h respectively.

The method may also comprise a step of separating at least one traffic lane of the electrolysis plant into at least two distinct lanes.

The method may, of course, include any other step to implement the system 1 described above in an existing electrolysis plant, such as setting up a monitoring unit as described above.

The method may further comprise a step of dismantling existing structures and replacement of these structures by structures functionally similar but of smaller dimensions than the dismantled structures.

Although the invention has been described in connection with specific embodiments, it is obvious that it is in no way limited to these and that it includes all technical equivalents of the means described and combinations thereof if they are within the scope of the invention.

Claims

CLAIMS:

1. System for managing logistics flows in an electrolysis plant comprising new anode assemblies and worn anode assemblies, wherein the management system comprises:

- a storage area, for storing new anode assemblies,

- a processing area, for processing worn anode assemblies,

- a production area, comprising a plurality of electrolytic cells for the production of liquid metal by electrolysis, and

- a fleet of transport vehicles for conveying new anode assemblies from the storage area to the production area and worn anode assemblies from the production area to the processing area, wherein the transport vehicles are designed to be able to carry only one anode assembly at a time.
2. System according to claim 1, wherein the transport vehicles comprise one or more electric motors and a set of supercapacitors for powering the electric motor(s), and the management system includes at least one charging area equipped with charging means to charge all of the supercapacitors when a vehicle is located in the charging area.
3. System according to claim 2, wherein the charging means are remote charging means.
4. System according to claim 2 or 3, wherein the at least one charging area is placed on a route used by transport vehicles when carrying an anode assembly from the storage area to the production area and / or on a route used by transport vehicles when carrying an anode assembly from the production area to the processing area.
5. System according to any of claims 1 to 4, wherein the management system further comprises a foundry area for solidifying the liquid metal, and a fleet of transport vehicles for conveying empty casting containers from the foundry area to the production area and casting containers containing liquid metal from the production area to the foundry area, wherein the casting containers are sized so as to be able to contain only the liquid metal cast in a single electrolytic cell out of the electrolytic cells of the production area when the casting cycle has a length dl of about thirty hours, and wherein the transport vehicles are sized to be able to carry only one casting container at a time.

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6. System according to claim 5, wherein the transport vehicles for conveying a single anode assembly at a time and transport vehicles for conveying a single casting container at a time are substantially identical, so that the fleets of transport vehicles can be considered as a single fleet of transport vehicles.
7. System according to any of claims 1 to 6, wherein the transport vehicles are automated, and the management system comprises a monitoring unit to monitor the movement of each transport vehicle with a view to conveying new anode assemblies from the storage area to the production area and worn anode assemblies from the production area to the processing area, and, if appropriate, with a view to conveying empty casting containers from the foundry area to the production area and casting containers containing liquid metal from the production area to the foundry area.
8. System according to any of claims 1 to 7, wherein the transport vehicles include automatic guiding means, designed to enable transport vehicles to move independently in the electrolysis plant.
9. System according to claim 8, wherein the management system comprises at least one first traffic area and at least one second traffic area, in which the transport vehicles are designed to run, and means for limiting the speed of the transport vehicles associated with guiding means to automatically limit the speed of the transport vehicles running in said at least one first traffic area to a first predetermined speed and the speed of the transport vehicles running in said at least one second traffic area to a second predetermined speed greater than the first predetermined speed.
10. Aluminum smelter comprising a plurality of rectangular electrolytic cells for aluminum production and a system according to any of claims 1 to 9, the aluminum smelter further comprising one or more buildings, the building(s) containing said plurality of electrolytic cells, and at least one working aisle arranged within said building containing said plurality of electrolytic cells, the working aisle being designed for transport vehicles to supply said plurality of electrolytic cells with new anode assemblies or removing a worn anode assembly from said plurality of electrolytic cells, and wherein said at least one working aisle has a width less than or equal to one third, preferably less than or equal to a quarter of the length of said electrolytic cells.

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11. Aluminum smelter according to claim 10 wherein the aluminum smelter has at least one traffic lane for the movement of transport vehicles outside the building(s) of the aluminum smelter; said at least one traffic lane has a width less than 6.5 m, and preferably less than or equal to 6 m.
12. Transport vehicle for implementing system according to any of claims 1 to 9, the transport vehicle comprising automatic guiding means to allow it to move independently, said transport vehicle being sized to carry only one anode assembly at a time.
13. Vehicle according to claim 12 wherein vehicle comprises lifting means designed to lift a single anode assembly, and a plurality of wheels supporting the vehicle and arranged to form a polygon within which the lifting means extend.
14. Vehicle according to claim 13 wherein vehicle comprises a single anode assembly carried by the lifting means and the surface of the polygon formed by the arrangement of the wheels is substantially between 0.5 and 1.5 times an area projected in a substantially horizontal plane of the anode assembly.
15. Vehicle according to claim 13 or 14 wherein vehicle comprises a single anode assembly carried by the lifting means and the lifting means have an overall support surface, on which the single anode assembly is designed to rest, the overall support surface being between 1 and 1.5 times the area projected in a substantially horizontal plane of the anode assembly.
16. Vehicle according to any of claims 13 to 15 wherein vehicle comprises a single anode assembly carried by the lifting means and an area projected in a substantially horizontal plane of the transport vehicle is substantially less than or equal to triple, and preferably less than or equal to double the area projected in a substantially horizontal plane of the single anode assembly.
17. Vehicle according to any of claims 13 to 16 wherein transport vehicle comprises a U-shaped frame having a central portion and two substantially parallel side portions between which extend the lifting means, and the wheels are arranged under the side portions and under the central portion.
18. Vehicle according to any of claims 12 to 17 wherein transport vehicle comprises one or more electric motors and a set of supercapacitors for powering the electric motor(s).

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19. Method for setting up the management system according to any of claims 1 to 9 in an electrolysis plant comprising a first fleet of transport vehicles, sized for simultaneously transporting a plurality of anode assemblies, the method comprising a step of replacing said first fleet of transport vehicles by a second fleet of transport vehicles, the second fleet of transport vehicles comprising at least one transport vehicle sized to be able to carry only one anode assembly at a time.
20. Method according to claim 19 wherein the method comprises a step of marking out at least one first traffic area and at least one second traffic area in which the transport vehicles of said second fleet of transport vehicles are designed to run, a step of determining a first predetermined speed corresponding to the maximum permissible speed of the transport vehicles of the second fleet in said at least one first traffic area, a step of determining a second predetermined speed greater than the first speed and corresponding to the maximum permitted speed of travel of the transport vehicles of the second fleet in said at least one second traffic area, and a step of setting up means for limiting the speed of the transport vehicles designed to limit the of speed of the transport vehicles running in said at least one first traffic area to the first predetermined speed, and the speed of transport vehicles running in said at least one second traffic area to the second predetermined speed greater than the first speed.