Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/34—Methods of heating
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D11/00—Process control or regulation for heat treatments
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
  • F27D2019/0003—Monitoring the temperature or a characteristic of the charge and using it as a controlling value
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
  • F27D2019/0006—Monitoring the characteristics (composition, quantities, temperature, pressure) of at least one of the gases of the kiln atmosphere and using it as a controlling value
  • F27D2019/0018—Monitoring the temperature of the atmosphere of the kiln
  • F27D2019/0021—Monitoring the temperature of the exhaust gases
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
  • F27D2019/0028—Regulation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
  • F27D2019/0087—Automatisation of the whole plant or activity

Definitions

• the invention relates to the controlled heating of a workpiece by a steel furnace or a heat treatment furnace, eg a reheating furnace.
• the control is done by a numerical modeling, simultaneous and in real time, of the heating of the room.
• US Patent 3,868,094 discloses a method of controlling heating for a metallurgical furnace having an upper zone and a lower zone.
• the method includes measuring, in one place, the surface temperature of a part that passes through the oven.
• the measurement signal is transmitted simultaneously to the upper and lower zone controllers.
• the controllers emit signals to the oven burners to maintain the desired upper and lower set temperatures.
• a first aspect of the present invention relates to a method for controlled heating of a workpiece, for example a steel semi-finished product, such as p. ex. a slab, a bloom, a billet, an ingot, a round, a blank, or the like, by a steel furnace or a heat treatment furnace comprising:
• the part to be heated may, for example, have a plate, slab, square or other shape.
• the part to be heated can be metal, including all grades of steel, from the most common grades to steel steels. High mechanical strength, including stainless steels and silicon steels.
• the furnace heating parameters can include, among others, the power, temperature and / or actuator settings, the settings controlling, for example, the furnace fuel flow rate and / or the speed of the furnace room. the oven.
• Room temperature indicators are directly or indirectly related to the room temperature. They are generally representative of the temperature of the room to be heated. Temperature indicators directly related to the temperature can be, for example, the average temperature of the room, a temperature profile of the room, or a three-dimensional map of the room temperature. Temperature indicators indirectly related to temperature include, for example, the latent heat of the room, entropy, enthalpy, etc.
• Obtaining the heating plan can be done by a numerical simulation taking into account the value of one or more indicators of the temperature of the room at the entrance of the oven, the desired value of the one or more indicators of the room temperature at the oven outlet, a three-dimensional model for the room to be heated, optionally a model of the oven. The numerical simulation then determines the heating plan including the evolution of one or more indicators of the room temperature during heating and optionally the furnace heating parameters necessary to achieve this evolution.
• Obtaining the heating plan can be done differently, for example, the heating plan by reading one or more data files including evolution of one or more indicators of the temperature of the room during its heating and than the furnace heating parameters necessary for the realization of this evolution. It will be appreciated that the heating plan need not be established at the location of the steel furnace or the heat treatment furnace, but may be developed elsewhere (eg in a computer center).
• the heating plan defines an evolution of the one or more indicators of the temperature and oven heating parameters that minimize energy consumption.
• the one or more temperature indicators defined in the heating plan are set values for the one or more temperature indicators adjusted during heating in the oven. In other words, an adjustment loop will act on the furnace parameters so that the values for the one or more current temperature indicators correspond to the set values for the one or more temperature indicators.
• the numerical modeling that is done simultaneously with the heating of the part operates in "real time", which means that the numerical modeling is conceived so as to provide the information on the one or more indicators of the temperature in the respect of strict time constraints.
• the design of the numerical modeling is done in such a way that the predicted values of the one or more temperature indicators are updated several times before the next reference time, so as to be able to adapt the oven heating parameters. .
• the time to obtain one or more temperature indicators by numerical modeling is much less than the time between two reference times.
• reference time refers to a time during the heating process (beginning and end included) to which it is desired to have a match between the one or more indicators according to the heating plane and the one or several indicators predicted by modeling.
• the reference instants may include, in particular, the end of the heating, moments to which the piece to be heated passes from one area of the oven to another, or other times.
• the instants of reference can be chosen according to the existing material, p. ex. depending on the low level control PLCs.
• the numerical modeling is preferably designed so that it can be performed on one or more graphics processors each comprising at least 1024 computational nuclei, preferably at least 2048 computational nuclei, still more preferably at least 4096 nuclei. of calculations.
• the difference between the one or more indicators of the temperature of the heating plane and one or more current indicators of the temperature of the room is calculated in the space of the parameters, formed by the one or more indicators of the room temperature, according to a metric.
• the latter can be defined in such a way as to assign a weight to each temperature indicator when calculating the difference. For example, the average temperature of the room can have a weight twice as large as that associated with its temperature profile when calculating the difference.
• the need for adaptation can be determined according to a tolerance threshold. If the deviation is below the tolerance threshold, no adaptation is made. If the deviation is greater than the tolerance threshold, the adaptation of the furnace heating parameters is made in order to reduce this difference at the subsequent reference instants.
• the method preferably includes assigning a priority to parts, which in case of incompatibilities of heating plans defines which heating plane has priority over others.
• This priority can be assigned to each part to be heated either by a user or automatically.
• One of these criteria could be, for example, the chemical composition of a part of which it is known that the temperature can not exceed a certain value or the mass of a part.
• the adaptation of the heating parameters is done, if necessary, in accordance with the priority assigned to each room. In the case where the rooms can be "priority" or "non-priority", the priority room will have its heating plan respected while the heating plan for non-priority rooms will not necessarily be respected.
• the adaptation of the furnace heating parameters for non-priority rooms is done in such a way as not to deflect the heating of each priority room from its heating plane.
• a multi-priority priority system (more than two) can be implemented.
• the adaptation of the furnace heating parameters will then be cascaded from the highest priority rooms to the lowest priority rooms. Adjusting the furnace heating parameters for lower priority rooms will ensure that the heating of each priority room is not deviated from the heating plane.
• the steel furnace or heat treatment furnace is a continuous furnace, eg a slider, tubular spar, movable hearth, rotating hearth furnace, etc.
• the oven is preferably subdivided into several control zones, the reference times being, for example, the moments at which the room passes from one zone to another.
• a second aspect of the present invention relates to software for controlling the heating of a part by a steel furnace or a heat treatment furnace.
• Such software includes instructions, stored on a computer medium, which, when executed by computer hardware, cause the computer hardware to implement the method comprising:
• the software is preferably designed to run in parallel on computer hardware comprising multiple compute cores.
• the computer hardware may be composed of one or more processors preferably comprising, each, at least 1024 computational nuclei, more preferably at least 2048 computational nuclei, still more preferably at least 4096 computational nuclei.
• the computer hardware preferably includes one or more graphics processors.
• the software may include, in addition, instructions, which, when executed by computer hardware, cause the computer hardware to implement the determination of the type of mesh to be used (for example a square mesh , triangular or hexagonal) depending on the geometry of the part to be heated.
• the software may be designed to determine the volume of voxels used in the numerical modeling of the room heater so that a relative error of each temperature indicator of said numerical simulation is less than 5%, preferably less than 1%, more preferably less than 0.5%.
• w (r) is a weighting factor depending on the position.
• EGR relative global error
• ERR Relative Local Error
• a third aspect of the present invention relates to a steel furnace or heat treatment furnace for heating a room comprising one or more detectors for measuring the current heating parameters of the furnace;
• the one or more detectors for measuring current heating parameters comprise one or more pyrometers, one or more fuel flow detectors injected into said furnace, one or more lower heating value detectors and Wobbe index. fuel injected into the furnace or a combination thereof.
• Fig. 1 represents the different levels of abstraction for controlling the heating of a room in a heat treatment furnace or a steel furnace;
• Fig. 2 is a simplified diagram showing a continuous heat treatment furnace for controlled heating of a room
• Fig. 3 is a flowchart showing the steps performed according to the invention for heating a room in a heat treatment furnace
• Fig. 4 is a simplified diagram showing a heat treatment furnace for controlled heating of several parts
• Fig. 5 is a graph showing the evolution of the temperature of a room during heating in comparison with the heating plane.
• FIG. 1 is a flowchart of a method for controlling a heat treatment furnace or a steel furnace according to one embodiment of the invention.
• the method comprises different levels organized in a hierarchical manner. In the illustrated example, this hierarchy is composed of four levels, numbered from 0 to 3, which are described in the following.
• the different levels can represent layers of abstraction. In such a case, we define, p. ex. by means of a programming interface, for each abstraction layer the types of inputs and outputs that it can receive, respectively emit.
• the method accepts customer orders, which set, e.g. ex. the type of the part, the final quality, the dimensions, the ultimate date of delivery, etc. Depending on the commands are then defined (automatically and / or manually) the set values in relation to the parts to be heated. These setpoints may include, in particular, the objective of final average temperature and the objective of temperature uniformity. Other peculiarities concerning the heating of the parts can also be defined, as p. ex. a maximum temperature not to be exceeded, a heating rate to be respected, etc. [33] The setpoint values for the parts to be heated are transferred to process level 2.
• the set point values 18 (high level) for the furnace are generated, which include, for example, the power objectives (overall and / or per furnace area) and / or fuel flow objectives for to the different burners, the oven temperature objectives (walls, exhaust gas, etc.), as well as the transit speed objectives of the parts in the oven or in its different zones.
• the furnace is controlled so as to reach and respect the high level setpoint values received from level 2.
• the setpoint values 18 are compared with current values, indicative of the operational status of the furnace. oven, measured by sensors 22 and / or estimated.
• Sensors 22 may include, for example, furnace wall temperature sensors, sensors measuring exhaust gas temperature, fuel flow sensors, and the like.
• the method thus performs a control loop which generates values of set point 20 (low level) for oven actuators 23 based on the high level setpoints 18 and the current operating state.
• the actuators controlled by level 1 include, e.g. ex. automatic valve actuators controlling the flow of fuel and / or engines controlling the progress of the parts to be heated.
• Level 0 has direct access to the material resources of the furnace and includes, for example, the drivers of the equipment used, in particular that of the actuators. At level 0, in particular, the translation of the low-level setpoint values 20 into electrical signals controlling the furnace actuators 23. Level 0 may include adjustment loops to ensure that the actuators 23 respond as expected to the level 1 controls. Such control loops may comprise sensors 24, eg sensors integrated in the actuators 23.
• each oven control level can be designed as a control loop that adjusts the parameters controlled by the level concerned to establish or maintain compliance with the setpoint values from the higher level. If the current state of the level concerned does not agree with the setpoint values imposed by the higher level, an adaptation of the setpoint values for the lower level is performed to establish or restore compliance.
• the hierarchy of different levels of abstraction allows an operator of the furnace to program it by defining set values 16 in relation to the part to be heated and / or setpoint values 18 of "high level" in relation to the oven without having to directly program the "low level” setpoints.
• the heating method according to the invention uses a heating plane to program the oven.
• the heating plan is in level 2.
• the heating plan is set for a room to be heated in order to reach the objectives that are relevant to it (eg average temperature). at the outlet of the oven, uniformity of the temperature distribution over the whole room.)
• the heating plan is established by a numerical simulation of the heating of the room by the oven.
• the simulation uses a model of the room as well as, optionally, a model of the oven that mimics the behavior of the oven.
• the types of settings that the oven model can undergo are identical to those that the level 2 process can perform on the actual oven. Simulation to get the plan to heating is performed as part of a cost function optimization process (eg reflecting energy consumption, heating time or other).
• the oven model settings in the simulation are adjusted until a satisfactory setting is found.
• the heating plan finally obtained contains an "optimal" heating curve of the room (ie data indicating the evolution of the room temperature depending on the progress of the heating) and the corresponding settings. from the oven. It should be noted that these adjustments will not necessarily be static but that the heating plan may determine a change in the settings according to the progress of the heating.
• the heating plan defines an initial programming of the oven. According to the invention, it is planned to monitor the respect of the heating plan by means of a thermal monitoring carried out by means of a three-dimensional numerical modeling of the room heating, in real time and simultaneously with the heating of the room. the room.
• the thermal monitoring is based, among other things, on operational parameters (current heating parameters) of the furnace which are injected into the numerical modeling which comprises a three-dimensional model of the part to be heated as well as, optionally, a model of the furnace. If the thermal state of the part to be heated, predicted by the numerical modeling, differs from the state predicted by the heating plane for the next reference time, an adaptation of the oven settings is carried out.
• This adaptation is chosen so as to restore at a later reference time (preferably at the next reference time) the conformity between the actual thermal state of the room and the thermal state prescribed by the heating plane.
• this method of adapting the oven settings represents an adjustment loop at level 2 of the aforementioned hierarchy, in which the temperature indicators of the room at the reference times provided by the heating plane are setpoint values.
• the parameters actively set by this loop advantageously include the fuel flow rates for the different burners. If these parameters are not directly accessible by level 2, they can be adjusted indirectly via power and / or temperature objectives imposed on level 1.
• FIG. Fig. 2 shows a continuous type heat treatment furnace 12 used for heating a workpiece 10 (eg, a steel semi-finished product).
• the oven 12 comprises a slideway 26 for carrying the part 10 to be heated.
• Oven 12 includes several sensors 22, 24 for measuring the current furnace heating parameters 12. These sensors 22, 24 comprise, for example, one or more pyrometers for measuring the temperature of the walls of the furnace 12, one or more fuel flow detectors for measuring the fuel flow injected into the burners, one or more detectors for measuring the lower heating value and / or the fuel Wobbe index, etc.
• the current furnace heating parameters 12 include quantities directly measured by the sensors 22, 24 (e.g., current oven wall temperature 12 or current fuel rates) and / or quantities derived from the measurements (e.g. current oven power 12).
• the method of heating a room by a multi-zone furnace is shown as a flow chart in FIG. 3.
• a heating plan is established (step S10) by numerical simulation based on a three-dimensional model of the room and, optionally, a furnace model. As indicated earlier in the text, the heating plan defines setpoint values for the room (room temperature indications at the reference times), which make it possible to reach, at the end of heating, the final average temperature. desired room and the uniformity of the desired final temperature.
• the heating plan also contains the oven settings which, according to the simulation, result in the optimum room heating curve.
• the heating plan is communicated to the oven (step S12).
• the settings provided by the heating plane are used to program (step S14) the oven for room heating.
• the thermal tracking of the workpiece is performed from the current furnace heating parameters measured by the sensors of the furnace.
• oven step S20
• the heating plane, a model of the room and, optionally, a model of the furnace, the room heating is modeled in the zone / and the heating state of the room is predicted. piece at the end of the zone / ' (step S22).
• step S24 The conformity of the heating of the room to the heating plane is verified at the next step (step S24): if the room heating predicted by the numerical modeling for the end of zone / is in accordance with the heating plane, no Changing the oven settings from those provided by the heating plan is necessary.
• step S26 an adaptation of the settings, intended to restore the conformity between the actual thermal state of the room and the state, at the next reference time (ie at the end of the zone / ' ).
• thermal prescribed by the heating plane is developed (step S26) and applied (step S28).
• steps S20, S22, S24, S26, S28 may be repeated several times on the same area / 'until the end of the zone / is not reached (step S31).
• a check for compliance of room heating with the heating plane could be done approximately every 10 to 60 s (eg every 30 s), but it will be understood that this frequency depends on several factors. , in particular the complexity of the modeling and the computing power made available.
• step S32 If the piece has not reached the end of the last oven area (checked in step S32), the piece then moves to the next oven area (in the flow chart, this translates as incrementing the index / at step S30). As long as the piece has not reached the end of the last zone of the furnace (checked in step S32), the method described above is repeated for the new zone. The arrival of the workpiece at the end of the last zone completes the heating of the workpiece (step S34).
• the conformity of the course of heating with the heating plane is verified by determining a quantity characterizing the difference between the set of theoretical values (of the heating plane) and the set of real quantities (estimated by modeling parallel to heating) in relation to the reference time.
• the deviation can be compared to a tolerance threshold to determine if a correction of settings is indicated.
• the evolution of the temperature of the room is given by the average room temperature at different reference times.
• Fig. 5 represents the average temperature 38 of the room during heating (continuous line), predicted on the basis of the numerical modeling and the average temperature 36 of the room during heating (discontinuous line) given by the heating plane.
• a correction of the oven settings in order to bring the heating of the room into conformity with the heating plane for the next reference time (steps S20, S22, S24, S26, S28, see Fig. 3), is performed.
• no further deviation between the heating plane and the actual heating of the room is noted.
• Three-dimensional numerical modeling carries out a thermal follow-up of the part by solving the physical equations relating, among other things, to the heat transfers (including, among other things, conductive and optionally radiation heat transfer).
• Digital modeling is performed in real time, which means that it is designed to provide the current temperature of the part under strict time constraints.
• the design of the numerical modeling is made in such a way as to guarantee (as a function of the computing powers implemented) that the temperature indicators predicted by the modeling are updated sufficiently frequently before the reference instants in order to be able to correct the furnace heating parameters to restore the conformity of the thermal state of the room to the heating plane for the next reference time.
• the numerical modeling is programmed so that it can be executed in parallel on one or more graphics processors, each of them having a multitude of calculation cores.
• the numerical modeling of the heating of the room by the oven on the computer hardware requires a discretization of the space (three-dimensional). This discretization inevitably introduces numerical inaccuracies.
• the voxels associated with the discretization may be of cubic form (or of another form). The larger the volume of the voxels, the greater the numerical error introduced by the discretization of the space. In case of poorly adapted mesh, the estimate of the average temperature of the piece obtained by numerical modeling will not be representative of the real value.
• the numerical modeling is carried out with a mesh in adequacy with the needs.
• the mesh can be defined, p. ex. by choosing voxels with defined shapes (eg parallelepipeds) and sufficiently small volumes. preferably of volume less than 1 cm 3 .
• FIG. 4 illustrates the simultaneous heating of several parts 10a-10c in the furnace 12. These parts 10a-10c may have, a priori, different shapes and different chemical compositions. According to one embodiment of the invention, a plan of heating is established for each room. When establishing these heating plans it is preferably taken into account the presence of other parts to be heated in the oven at different times.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Control Of Heat Treatment Processes (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
• Feedback Control In General (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)
• Tunnel Furnaces (AREA)

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• 2017
  • 2017-04-28 CA CA3021529A patent/CA3021529A1/fr not_active Abandoned
  • 2017-04-28 WO PCT/EP2017/060153 patent/WO2017191039A1/fr unknown
  • 2017-04-28 JP JP2018557043A patent/JP2019523341A/ja active Pending
  • 2017-04-28 US US16/097,862 patent/US20190144961A1/en not_active Abandoned
  • 2017-04-28 RU RU2018140518A patent/RU2018140518A/ru not_active Application Discontinuation
  • 2017-04-28 CN CN201780026481.5A patent/CN109072333A/zh active Pending
  • 2017-04-28 EP EP17722709.7A patent/EP3452623A1/fr not_active Withdrawn

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