EP4237778A1 - Four et procédé pour faire fonctionner un four - Google Patents

Four et procédé pour faire fonctionner un four

Info

Publication number
EP4237778A1
EP4237778A1 EP21748537.4A EP21748537A EP4237778A1 EP 4237778 A1 EP4237778 A1 EP 4237778A1 EP 21748537 A EP21748537 A EP 21748537A EP 4237778 A1 EP4237778 A1 EP 4237778A1
Authority
EP
European Patent Office
Prior art keywords
furnace
control device
heating
ramp
determined
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21748537.4A
Other languages
German (de)
English (en)
Inventor
Frank Heinke
Detlef Maiwald
Hans-Joerg Seifert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Innovatherm Prof Dr Leisenberg GmbH and Co KG
Original Assignee
Innovatherm Prof Dr Leisenberg GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Innovatherm Prof Dr Leisenberg GmbH and Co KG filed Critical Innovatherm Prof Dr Leisenberg GmbH and Co KG
Publication of EP4237778A1 publication Critical patent/EP4237778A1/fr
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B13/00—Furnaces with both stationary charge and progression of heating, e.g. of ring type, of type in which segmental kiln moves over stationary charge
    • F27B13/06—Details, accessories, or equipment peculiar to furnaces of this type
    • F27B13/14—Arrangement of controlling, monitoring, alarm or like 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
    • 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
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety 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
    • F27D2019/0009—Monitoring the pressure in an enclosure or kiln zone
    • 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

Definitions

  • the invention relates to a method for operating a furnace, in particular an anode furnace, a control device for a furnace and a furnace, the furnace being formed from a plurality of heating channels and furnace chambers, the furnace chambers for accommodating carbonaceous bodies, in particular anodes, and the Heating ducts serve to control the temperature of the furnace chambers, with the furnace comprising at least one furnace unit, with the furnace unit comprising a heating zone, a firing zone and a cooling zone, which in turn are formed from at least one section comprising furnace chambers, with a suction ramp in one section of the heating zone and a suction ramp in a
  • a burner ramp of the furnace unit is arranged in the fire zone section, with process air being heated in the heating channels of the fire zone by means of the burner ramp and exhaust gas being extracted from the heating channels of the heating zone by means of the suction ramp, with operation of the ramps by means of a control device tion of the oven unit is controlled.
  • the present method and the device are used, for example, in the production of anodes that are required for the fused-salt electrolysis for the production of primary aluminum.
  • These anodes or carbon-containing bodies are made from petroleum coke with the addition of pitch as a binder in a shaping process as so-called “green anodes” or “raw anodes”, which are then sintered in an anode furnace or kiln.
  • This sintering process takes place in a defined heat treatment process in which the anodes go through three phases, namely a heating phase, a sintering phase and a cooling phase.
  • the raw anodes are located in a heating zone of a "fire" composed of the heating zone, a firing zone and a cooling zone, and are preheated by the waste heat from the firing zone from already finished sintered carbonaceous bodies before the preheated anodes in the firing zone the sintering temperature of around 1200° Celsius.
  • the various aforementioned zones are defined by an alternating continuous arrangement of different units above furnace chambers or heating ducts, which accommodate the anodes.
  • the firing zone which is arranged between the heating zone and the cooling zone, is defined by positioning a burner device or one or more so-called burner ramps above selected furnace chambers or heating channels.
  • a burner device or one or more so-called burner ramps In the cooling zone there are anodes that have been fired immediately beforehand, i.e. heated to the sintering temperature.
  • Above the cooling zone there is a fan device or a so-called cooling ramp, by means of which air is blown into the heating channels of the cooling zone.
  • the air is removed by a suction device arranged above the heating zone or a so-called suction ramp through the heating ducts from the cooling zone through the fire zone into the heating zone and from there as flue gas or waste gas passed through a flue gas cleaning system and released into the environment.
  • the exhaust ramp and the burner ramp together with the cooling ramp and the heating channels form a furnace unit.
  • a furnace to comprise a plurality of furnace units, the units of which are successively displaced above the furnace chambers or heating ducts for the subsequent heat treatment of the raw anodes or anodes.
  • anode furnaces which can be designed in different designs as an open or closed ring furnace, there is the problem that a volume flow of the process air or exhaust gases guided through the furnace cannot be measured directly and only with great effort. This is to ensure that sufficient oxygen is available for burning a fuel of the burner device in the heating channels of the furnace.
  • the volume flow is determined indirectly by evaluating pressure and temperature measurements on the heating channels and control signals from a process controller.
  • an attempt is made to determine the volume flow by means of an indirect measurement, for example a pressure measurement in the heating channel and its relationship to a suction capacity of the suction ramp, as described in more detail in WO 2013/044968 A1.
  • an indirect measurement for example a pressure measurement in the heating channel and its relationship to a suction capacity of the suction ramp, as described in more detail in WO 2013/044968 A1.
  • proper functioning of the kiln according to a desired or optimal firing curve cannot be guaranteed if e.g. a heating channel cover is open or improperly closed, or a heating channel is clogged or blocked.
  • a volume flow rate is evaluated by trained furnace personnel as part of a furnace tour and/or by a Evaluation of status information of a process control carried out at regular intervals. If a malfunction of the kiln is detected, for example caused by a blockage or leak in the heating channel, this blockage or leak is then removed manually by the kiln personnel. Since a kiln tour is carried out at intervals of up to four hours, for example, dangerous operating states of the kiln resulting from a blockage or leak, which can lead to deflagration, fire or explosions, may not be detected in good time.
  • the object of the present invention is therefore to propose a method for operating a kiln and a control device for a kiln, with which the operation of the kiln can be improved.
  • the furnace is formed from a plurality of heating ducts and furnace chambers, with the furnace chambers serving to accommodate bodies containing carbon, particularly anodes, and the heating ducts serving to control the temperature of the furnace chambers, with the furnace having at least one Furnace unit comprises, wherein the furnace unit comprises a heating zone, a firing zone and a cooling zone, which in turn are formed from sections comprising at least one furnace chambers, wherein a suction ramp of the furnace unit is arranged in a section of the heating zone and a burner ramp of the furnace unit is arranged in a section of the firing zone, wherein by means the burner ramp combustion air or process air is heated in the heating ducts of the firing zone and hot air or exhaust gas is sucked out of the heating ducts of the heating zone by means of the suction ramp, wherein operation of the ramps is controlled by a control device of the furnace unit, with middle ls the tax tion device for at least two sections
  • An enthalpy flow of the respective sections is determined by means of the control device, wherein the enthalpy flow can be calculated by the control device, for example by means of a mathematical model.
  • the enthalpy flow is understood to mean the enthalpy transported in a unit of time in the relevant section or the enthalpy transported in the process air in the heating channels.
  • the enthalpy flow can easily be calculated via a ratio of a respective pressure and a respective volume flow in a plurality of heating channels. Since the sections are connected to each other in a series connection, an enthalpy flow changes in a flow direction across subsequent sections, which also affects an operating state of the kiln.
  • the control device calculates the respective enthalpy flow for at least two sections and, in a further step, a difference between the respective enthalpy flows.
  • the difference or the differences are determined as a key figure or actual key figure, with the key figure being the difference itself or just the sign resulting from the difference.
  • the actual index is compared with a presupposed index or a target index that is present during normal operation of the furnace. Normal operation is understood here to mean trouble-free operation, ie operation without blockages or leaks in the heating channels. If the actual characteristic number deviates significantly from the target characteristic number, there is a high probability that an operating state of the furnace is disrupted by a leak and/or a blockage of a heating channel.
  • the key figures and the ratios can easily be determined by calculation or mathematically, for example with a computer program product of the control device. It is thus easy to determine whether a ratio of the respective characteristic numbers corresponds to or deviates from a presupposed operating state of the furnace or a firing curve. In the event of a deviation, a leak and/or blockage in a heating channel can lead to critical operating states of the furnace. This deviation can be signaled by the control device, for example, in order to inform the furnace personnel, so that the furnace personnel can carry out troubleshooting or manual adjustments in deviation from the regular furnace tours.
  • an identification of a state of a heating channel or a status of the furnace is based exclusively on a comparison of mathematically determined process variables.
  • the enthalpy flow can be calculated by means of the control device from a ratio of a respective pressure, a respective temperature and a respective mass flow or volume flow in the heating channel.
  • Known material properties of an exhaust gas or the process air can be taken into account.
  • the enthalpy flow in the heating channel of the heating zone and/or the firing zone is determined. Since this may be caused by the e respective combustion processes result in mass flow differences, these can also be taken into account.
  • a mass flow in the heating channel of the aforementioned zones can be determined separately from each other. This enables a differentiated view of the operating status in the respective zones of the kiln.
  • the mass flow can also be determined more precisely if a change in density of air in the heating duct is calculated from a temperature gradient over the respective sections or heating ducts, and this change in density is taken into account when determining the mass flow.
  • the control device can identify a blockage and/or leakage of the heating channel as the status of the furnace, wherein the control device can issue an alarm and/or stop a fuel supply of the burner ramp. If a safe operating state cannot be established, the furnace can be switched to a safe operating state by switching off the primary fuel supply to the burner ramp or the burners in the burner ramp. Provision can also be made for a message or an alarm to be output after detecting a leak or a blockage in the heating channel, in which case the furnace personnel can then examine the affected heating channel and, if necessary, rectify the malfunction.
  • a volume flow of the sections between the suction ramp and the cooling ramp can be determined by means of the control device on the basis of a pressure measured in the heating channel or another physical variable in the heating channel.
  • This volume flow can be calculated by the control device using a mathematical model.
  • a pressure in the heating channel can be measured in each section and at the exit of the firing zone.
  • the volume flow in the heating channel can be determined by means of the control device from a ratio of suction capacity and pressure in the suction ramp and a ratio of suction capacity and pressure in the heating channel. the The ratios in question can each be formed separately from one another and the volume tower can be derived from them.
  • a consistency of volume flow and enthalpy flow can also be calculated by means of the control device, it being possible to determine any leakage air quantities of the heating channels on the basis of the calculation. If the volume flow and the enthalpy flow deviate from an assumed ratio, this can also indicate a possible malfunction.
  • an enthalpy flow can be determined for at least one position P in each of the sections, with a status of the heating channel, the section and/or the respective position P being able to be determined on the basis of the comparison.
  • the position P means a real or assumed point within a heating channel of a section.
  • a section can have a plurality of positions Pn, for example at each opening of the heating channel.
  • the heating channel can be divided into 20 different positions P1 to P20.
  • Each position P is then classified by the controller as a balance area.
  • Each balance area or each position P has a fluidic input and output such that each position P is assigned operating parameters. These operating parameters are actually measured or determined by a computational model.
  • an operating parameter such as a temperature
  • a temperature change at a first position P I in the direction of flow causes a temperature change in all subsequent positions P l +n.
  • a status of the relevant heating channel can be determined even more precisely by this model of balancing operating parameters for each position P or the respective enthalpy flows.
  • An enthalpy flow of all positions Pn can be determined by means of the control device. This is not absolutely necessary, since not all positions PI or trains of heating ducts have to be included in a determination of the characteristic numbers, but a status of the respective heating duct can then be determined even more precisely. For example, it can be provided that a position P is defined in each train of a heating channel, starting from a measuring ramp or zero ramp up to a suction ramp.
  • the control device can be used to determine a cumulative mass flow for the respective position P, preferably for all positions Pn of the kiln, with the cumulative mass flow being made up of partial mass flows of a primary fuel, a secondary fuel, sucked-in false air and/or an exhaust gas from the preceding position in a flow direction Pn-1 can be determined.
  • the primary fuel and the secondary fuel can be determined by measurement or computation using the control device.
  • the false air sucked in at the respective position P is sucked in from the ambient air during regular operation of the furnace by a negative pressure present in the heating channel. This false air can be stored for each position P as a specification or an operating parameter in the control device.
  • the exhaust gas resulting from the amount of fuel burned can be calculated by the control device from the amount of fuel or the total amount of fuel. From these partial mass flows, the control device then calculates the total mass flow for the respective position P, in particular taking into account the partial mass flows of the preceding position Pn-1. Overall, it is thus possible to determine a respective total mass flow over the length of the heating channel for each position Pn of the heating channel.
  • the respective cumulative mass flows can in turn be used to determine a pressure loss along the relevant heating channel. In this way, a differential pressure between adjacent positions P can be determined.
  • the respectively determined pressures and mass flows for each of the positions Pn can thus be used for a particularly precise determination of the enthalpy flow.
  • a primary fuel quantity of the burner ramp can be determined by means of the control device, wherein a secondary fuel quantity of the heating zone and/or the burner zone can be determined by means of the control device depending on at least one material property of the carbonaceous body.
  • a fuel such as gas or oil, is regularly burned with the burner ramp or burners of the burner ramp, preferably a plurality of burner ramps.
  • the control device uses the control device to determine an amount of fuel that is consumed or burned by the burner ramp in the time segment in relation to a subsection.
  • the amount of fuel consumed by the burner ramp or a primary amount of fuel can, for example, be determined metrologically, using a quantity counter or the like.
  • the secondary fuel amount can be, for example, a fuel amount of pitch, which is contained in the carbon-containing bodies or raw anodes.
  • Pitch is regularly used as a binder in a raw anode forming process.
  • the pitch or pitch distillates can be released at a temperature between 200°C and 600°C. Depending on the material composition of the carbon-containing body or the anode, this contains a greater or lesser amount of pitch, which is known in principle. Depending on the temperature of the respective anode and its heating-up behavior, a greater or lesser amount of pitch distillate can be released, which burns in the combustion zone.
  • This secondary fuel quantity of pitch distillate or other substances contained in the raw anodes that can be used as fuel results in a change in the ratio of fuel quantity and process air.
  • control device can determine the secondary fuel quantity.
  • this determination can be made, for example, via a quantity of pitch present in the raw anodes.
  • a continuous determination of the amount of secondary fuel by determining the heating of the carbonaceous products and a dependent thereon Combustible components are released using a thermodynamic calculation model.
  • the primary fuel quantity can be calculated by means of the control device as a function of a temperature measured in the heating channel of the firing zone and/or from control values of the burner ramp. In this respect, it is then no longer necessary to carry out a quantity of fuel using quantity counters, which then also do not have to be present. In principle, it is still possible to determine the primary fuel quantity by directly detecting pulse times for oil or gas injection from individual burners. Since a temperature in the heating channel of the fire zone is measured anyway for the operation of a burner ramp, this temperature can advantageously be used by the control device to calculate the primary fuel quantity. This calculation can be carried out, for example, by using empirical values for fuel consumption at specific temperatures measured in the fire zone. The calculation can be done using a mathematical function of the primary fuel quantity and the temperature.
  • the amount of secondary fuel in the heating zone can be calculated or estimated as a function of a mass loss, degree of coking and/or a temperature of the anodes or carbonaceous bodies. Consequently, the secondary fuel quantity can be calculated by the control device using a mathematical model.
  • a heat content or a temperature of the carbonaceous body has an influence on the release of pitch distillates, for example, so that if the material property of the carbonaceous body is known, for example a mass fraction of pitch, the residence time of the carbonaceous body in the kiln, a temperature level of the carbonaceous body during this period of time, thus a degree of coking and thus also a loss of mass, a proportion released by the carbonaceous bodies in a period of time primary fuel amount can be calculated by the control device.
  • a direct measurement of a temperature of carbon-containing bodies can take place in different sections.
  • the direct measurement of a temperature can also be carried out on individual carbonaceous bodies as a reference measurement.
  • the control device can store these measured values and recalculate them depending on the position of a carbonaceous body or an anode in a section or zone for the carbonaceous body, so that the control device represents a degree of coking for the relevant carbonaceous body and thus one of the carbonaceous body secondary fuel quantity can be continuously adjusted.
  • the control device can calculate the temperature of the carbonaceous bodies.
  • the control device can also calculate the temperature of the bodies containing carbon using a mathematical model. This calculation can take place using the temperatures measured by the control device in the heating channels of the kiln. Furthermore, the respective temperature can be measured on the suction ramp, on the burner ramp and in the heating channels of other sections. From these temperatures of the furnace, which are then measured essentially simultaneously, the control device can calculate the temperature of the respective carbonaceous bodies. This calculation can be carried out taking into account other operating parameters of the kiln. The calculation can also be carried out on the basis of empirical values, which are represented by mathematical functions, for example.
  • a direct measurement of the temperature of the carbon-containing bodies is then no longer necessary during regular operation of the furnace.
  • the controller may calculate a total fuel amount from the primary fuel amount and the secondary fuel amount. In this way, the amounts of fuel that are supplied to the heating channels in the heating zone and in the firing zone can be determined more precisely, and the ratios of these amounts of fuel to residual oxygen contained in the exhaust gas can be determined for optimum combustion. Consequently, a ratio of process air and amount of fuel can also be determined more accurately.
  • the control device can assign a connection channel on the suction ramp as a position P I , the heating channel on a sensor for temperature measurement and flow direction in front of the suction ramp as a position P7, the heating channel on a measuring ramp in the flow direction in front of the sensor as a position P 10 and/or the heating channel on the burner ramp upstream of the measuring ramp can be used as a position P 13 .
  • This comparison can be reliably determined simply by using these positions P to determine the status of the heating channel.
  • the control device can use the difference in the enthalpy flows from position P7-P1, P10-P7 and/or P13-P10 as a key figure, and a ratio of the enthalpy flows in positions P1, P7 and/or P10 to P 13 , and in each case the volume flows in position PI , P7, P 10 and/or P 13 are calculated.
  • the respective enthalpy flows at these positions P can be determined by the control device, for example taking into account temperature-dependent material parameters of the process air.
  • the differences in the enthalpy flows or volume flows of the relevant positions P and their ratios can easily be used to determine the key figures.
  • a normal condition of the kiln or trouble-free operation can be defined by the differences in the content pie currents are always positive, a ratio of the enthalpy currents: position 10/position P 13 > position P7/position P30 > position P 1/position P 13. Operating states deviating from the normal operation defined in this way can then be defined as a fault.
  • the control device can calculate a respective pressure in the heating channel for the subsequent position Pn-1. Since a pressure is regularly 0 Pa at the zero pressure ramp or position P20, a pressure drop can be calculated from this for the subsequent positions Pn-1 without measuring this pressure drop at these positions Pn-1. Furthermore, the pressure in the individual positions Pn-1 can then be used to determine a respective volume flow or mass flow for these positions Pn-1.
  • a pressure and/or a temperature can be measured at the measuring ramp, wherein the control device can correct a calculated pressure and/or a temperature according to the measured pressure and/or the temperature.
  • the measurement ramp located at position P 10 can consequently be used to correct the calculated pressure and/or the temperature at calculated position P 10 .
  • the control device can first calculate the pressure and/or temperature at the measuring ramp, and the calculation can be repeated iteratively by varying parameters until there is sufficient agreement between the measured and calculated pressure or temperature at the measuring ramp is reached.
  • the respective key figures for the remaining position P, at which no measurement is possible, can thus be determined even more precisely.
  • the control device can compare the characteristic number determined by the control device with predetermined signs of assumed characteristic numbers and/or ratios of assumed Carry out key figures, whereby the status of the heating channel can be determined on the basis of the comparison. For example, a blockage in the heating channel between the measuring ramp and a sensor of a burner ramp can be determined if a difference in the enthalpy flows position P7 - position PI is negative, and if a relation of the differences position P7 - position PI ⁇ position P 13 - position P 10 ⁇ Position P 10 - Position P7, and if a relation of the enthalpy flow ratios Position P 10/Position P 13 > Position P l/Position P 13 > Position P7/Position P 13, and if the respective volume flows Position P7 ⁇ Position PI ⁇ position P 10 ⁇ position P 13 .
  • the control device can identify and further process a partial or total blockage between position P7 and position P13. Furthermore, the control device can identify a blockage in the heating channel between position 10 and a last burner ramp with position P 15 if a difference in enthalpy flows position P7 - position PI is negative, and if a relation of the differences position P7 - position PI ⁇ position P 13 - position P 10 ⁇ position P 10 - position P7, and the respective volume flows position P7 ⁇ position P 10 ⁇ position PI ⁇ position P 13 are. If all conditions are met, the control device determines the status of a partial or total blockage between the measurement ramp and the burner ramp in the heating channel.
  • a leak in the heating channel in the area of the burner ramp or burner ramps can be identified if a difference in the enthalpy flows position P7 - position PI is negative, and if a relation of the differences position P7 - position PI ⁇ position P10 - position P7 ⁇ Position P 13 - Position P 10 and when a relation of the enthalpy flow ratios Position P 1 / Position P 13 > Position P 10 / Position P 13 > Position P7 / Position P 13 . If these conditions are met, the control device can determine a leak in the heating channel as a status.
  • control device can carry out a comparison of the key figures determined by the control device with key figures stored in the control device, it being possible to determine a probability of the status of the heating channel on the basis of the comparison. By comparing it with a standard situation, the control device can determine and further process the probability in the range from 0 to 100% for the presence of a blockage or a leak in the heating channel. This ascertained probability can be made available to the furnace personnel as information or can be further processed for further transfer to a controller of the furnace, for example to trigger an interruption in the supply of fuel to the burner ramp.
  • a loss of pressure in the heating channel and/or a possible leakage air quantity can be taken into account for the respective positions P of the heating zone and/or the firing zone, depending on the shape of the heating channel.
  • the quantity of secondary air can be calculated by the control device using a mathematical model.
  • the leakage air volume can be calculated iteratively, for example, on the basis of empirical values that are represented by mathematical functions.
  • the amount of air introduced into the heating channels can be determined, for example, in the area of the cooling zone, for example on a fan ramp.
  • the amount of air at the blower ramp can be determined by determining a flap position of a throttle flap.
  • a cross section of an intake duct can be varied by adjusting the throttle flap, so that the amount of air introduced into the heating ducts depends, among other things, on the set cross section of the intake duct. If a throttle flap or a similar device is used, a flap position, for example specified in degrees of angle relative to the intake port, can be used to draw conclusions about an intake capacity or air quantity.
  • the air volume can be used by the control device to calculate the volume flow.
  • the amount of air introduced can be determined by measuring the pressure in the heating ducts between the fan ramp and the burner ramp. It is also possible to determine the amount of air that has been brought in via the speed of the fans.
  • the volume flow and/or the enthalpy flow can be regulated by the control device. This regulation of the calculated volumetric flow or enthalpy flow can take place by including further operating parameters, for example an amount of leakage air or other measurement data.
  • the volume flow, preferably of the sections and/or the suction ramp and/or the cooling ramp, and/or an amount of air introduced can be adjusted by means of the control device in such a way that a target ratio of process air and the primary fuel quantity and/or secondary fuel quantity, preferably the total fuel quantity, can be achieved.
  • the control device can calculate an actual ratio of process air and amount of fuel and regulate it by adjusting the amount of air introduced according to the target ratio.
  • the control device can have one or more controllers, for example PID controllers. It can then be ensured at any time that the ratio of process air and fuel quantity does not deviate to such an extent that dangerous operating conditions arise. A state that is optimal for combustion of the different fuels can also be set.
  • This adaptation can take place by regulating the volume flow at the suction ramp and/or the cooling ramp using the control device.
  • This regulation of the volume flow can be accomplished by actuating throttle valves on the suction ramp and/or the cooling ramp.
  • the regulation can act on a motorized drive of the throttle valve or the throttle valves, so that the volume flow is influenced.
  • the introduced primary amount of fuel can be adjusted by means of the control device in such a way that a setpoint ratio of process air and the total amount of fuel that is predefined in the control device can be achieved. Consequently, it is also possible to regulate an actual ratio of process air and total amount of fuel by dosing the amount of fuel at the burner ramp.
  • the primary fuel quantity can be regulated in connection with a regulation of the volume flow, in which case the control device can then also form a cascade regulation.
  • the control device is designed to operate a furnace, in particular an anode furnace, with the furnace being formed from a plurality of heating ducts and furnace chambers, with the furnace chambers serving to accommodate bodies containing carbon, particularly anodes, and the heating ducts serving to control the temperature of the furnace chambers, with the
  • the furnace comprises at least one furnace unit, the furnace unit comprising a heating zone, a firing zone and a cooling zone, which in turn are formed from at least one section comprising furnace chambers, with a suction ramp being arranged in one section of the heating zone and a burner ramp of the furnace unit being arranged in a section of the firing zone process air can be heated in the heating channels of the fire zone by means of the burner ramp and exhaust gas can be sucked out of the heating channels of the heating zone by means of the suction ramp, wherein operation of the ramps can be controlled by means of the control device of the furnace unit, whereby by means of the control device, a fuel quantity of the burner ramp can be determined, with the control device being able to
  • the furnace according to the invention in particular anode furnace, comprises a control device according to the invention. Further embodiments of a kiln result from the feature descriptions of the dependent claims referring back to method claim 1.
  • Fig. 1 is a schematic representation of a kiln in a perspective rule view
  • FIG. 2 shows a schematic illustration of a furnace unit of the furnace in a longitudinal sectional view
  • Fig. 3 shows a temperature distribution in the furnace unit
  • Figure 4 is a partial view of the oven unit of Figure 2;
  • FIG. 5 shows a flowchart for an embodiment of the method for operating a furnace.
  • FIGS. 1 and 2 shows a schematic representation of an anode furnace or furnace 10 with a furnace unit 11.
  • the furnace 10 has a plurality of heating channels 12 which run parallel along intermediate furnace chambers 13.
  • the furnace chambers 13 serve to accommodate anodes or carbon-containing bodies, which are not shown in detail here.
  • the heating ducts 12 meander in the longitudinal direction of the kiln 10 and have heating duct openings 14 at regular intervals are each covered with a heating duct cover, not shown in detail here.
  • Furnace unit 11 further includes a suction ramp 15, one or more burner ramps 16 and a cooling ramp 17. Their position on furnace 10 defines a heating zone 18, a firing zone 19 and a cooling zone 20, depending on the function Body is the furnace unit 1 1 relative to the furnace chambers 13 or the carbonaceous body by moving the suction ramp 15, the burner ramps 16 and the cooling ramp 17 in the longitudinal direction of the furnace 10, so that all the anodes or carbonaceous bodies in the anode furnace 10 the zones 18 to 20 go through.
  • the suction ramp 15 is essentially formed from a collecting duct 21 which is connected via a ring duct 22 to an exhaust gas purification system not shown here.
  • the collecting duct 21 is in turn connected to a heating duct opening 14 via a connecting duct 23 , a throttle flap 24 being arranged on the connecting duct 23 here.
  • a measuring value pickup not shown here, for measuring the pressure within the collecting duct 21 and another measuring value pickup 25 for measuring the temperature in each heating duct 12 are arranged directly in front of the collecting duct 21 and connected to it via a data line 26 .
  • a measuring ramp 27 with measured value recorders 28 for each heating channel 12 is arranged in the heating zone 18 . A pressure and a temperature in the relevant section of the heating channel 12 can be determined by means of the measuring ramp 27 .
  • burner ramps 16 with burners 30 and measuring sensors 31 for each heating channel 12 are set up.
  • the burners 30 each burn an ignitable fuel in the heating duct 12, with a Burner temperature is measured. It is thus possible to set a desired burner temperature in the fire zone 19 .
  • the cooling zone 20 includes the cooling ramp 17 which is formed from a supply channel 32 with respective connection channels 33 and throttle valves 34 for connection to the heating channels 12 .
  • Fresh air is blown into the heating channels 12 via the supply channel 32 .
  • the fresh air cools the heating channels 12 or the anodes or carbonaceous bodies located in the furnace chambers 13 in the region of the cooling zone 20 , the fresh air being continuously heated until it reaches the firing zone 19 .
  • 3 shows a diagram of the temperature distribution in relation to the length of the heating channel 12 and the zones 18 to 20.
  • a measuring ramp or also a so-called zero pressure ramp 35 with measuring sensors 36 is arranged in the cooling zone 20 .
  • the measuring sensors 36 are used to record a pressure in the respective heating channels 12.
  • the pressure in the heating channel 12 essentially assumes the value 0, with an overpressure between the measuring sensors 36 and the cooling ramp 17 and between the measuring sensors 36 and of the suction ramp 15, a negative pressure forms in the heating channels 12. Consequently, the fresh air flows from the cooling ramp 17 through the heating ducts 12 to the suction ramp 15.
  • the ramps 15 to 17 are each arranged in sections 37 to 42, with the sections 37 to 42 in turn being formed from heating duct sections 12. Sections adjoining sections 37 to 42 are not shown in detail here in order to simplify the figure.
  • FIG. 4 shows the furnace unit 11 of the furnace 10 already shown in FIG. 2 in a partial representation.
  • operation of the kiln 10 or the suction ramp 15, the burner ramp 16 and the cooling ramp 17 is controlled by means of a control device, not shown here, of the furnace unit 11, the control device having at least one device for data processing, for example a programmable logic controller or a computer, which is used to run a computer program product or at least one piece of software.
  • An enthalpy flow is determined by means of the control device for at least two of the sections 37 to 42, with a difference between the respective enthalpy flows being determined as a code number, with the code number determined in this way being compared with a pre-determined code number, with the comparison being used to determine a status of the furnace 10 or the oven unit 1 1 is determined.
  • positions P1 to P20 are defined in sections 37 to 41, which represent balance areas for which the control device determines an enthalpy flow and a volume flow.
  • the positions P1 to P20 are distributed on the kiln 10 in such a way that possible system design features of the kiln influencing the enthalpy flow and the volume flow are taken into account.
  • the connecting duct 23 is positioned at P1
  • the heating duct 12 is sealed at position P5
  • the measured value sensor 25 shown in FIG. 2 at position P7 the measured value sensor 28 shown in FIG.
  • the position P10 is represented by the position P10, the measured value sensor 31 by the positions P13 to P18 and the measured value sensor or sensors 36 by the position P20. Above the positions P 14 to P 19 burners 30 are positioned.
  • the position P20 thus corresponds to the zero pressure ramp 35 and the position P 10 to the measuring ramp 27.
  • the positions P I to P5 relate to the suction ramp 15.
  • a value for a possible leak or false air is specified in the control device.
  • the respective volume flows are determined using the actually measured or determined temperatures and pressures from the mass flows identified in this way.
  • the respective enthalpy flows of the process air can now from the known material properties of the process air and the mass flows are calculated.
  • the control device determines a primary fuel quantity of the burner ramps 16 .
  • the control device calculates a temperature of the anodes or carbonaceous bodies, not shown here, and on this basis a secondary fuel quantity of the heating zone 18 is determined as a function of at least one material property of the anodes or carbonaceous bodies.
  • the control device calculates a total fuel quantity from the primary fuel quantity and the secondary fuel quantity.
  • a pressure is measured in a position P 10 and in a position P20, the differential pressure then being known being cut to the other balance sheets or positions P being divided.
  • a mass flow for the waste gas or process air can now be calculated from the respective differential pressure, the temperature and the flow parameters.
  • a respective total mass flow is made up of the mass flows for exhaust gas, secondary air, primary and secondary fuel.
  • the actually measured values for pressure and temperature at the position P 10 can be compared by the control device with the calculated measured values, whereby the calculation can be adapted to the actually measured values by an iterative repetition of the calculation by means of parameter variation.
  • the total mass flow calculated in this way for position P 10 is in turn divided over the subsequent positions P, as described above, and calculated for the respective positions P, taking into account leakage air, etc.
  • the resulting enthalpy flows and volume flows for the respective positions P are then further processed by the control device.
  • a difference in enthalpy flows and a ratio of the enthalpy flows and the volume flows is calculated.
  • the control device Since the key figures for a normal plant condition of the kiln 10 or the furnace unit 11 are known and stored in the control device, the control device compares the determined key figures or actual key figures with the assumed key figures or target key figures for a normal plant state. Depending on the result of the comparison, the control device can identify a blockage and/or a leak in the area of one of the positions PI to P20. In the comparison with the assumed key figures, the control device can also determine a probability in a range from 0% to 100% for the presence of this blockage or leakage.
  • control device detects blockages in heating channel 12 in sections 37 and 38 up to measuring ramp 27, blockages in heating channel 12 between measuring ramp 27 and fire zone 19, leaks in heating channel 12 in the area of sections 37 and 38 and a general condition of the heating channel 12 identified. If the control device identifies a blockage and/or a leak, it can first issue an alarm and/or stop fuel supply to the burner ramps 16 of the affected heating channel 12, which puts the furnace 10 in a safe operating state.
  • FIG. 5 shows a schematic representation of a process sequence for identifying blockages and/or leaks in a furnace using the control device.
  • a method step 43 as previously described, an enthalpy flow is determined for the respective positions P1 to P20.
  • a difference and a ratio of enthalpy flows of selected positions P are calculated.
  • the control device determines characteristic numbers from the calculation of the differences and ratios and compares them with one another.
  • these key figures are compared with the key figures required for a normal system state. The assumed key figures are stored in the control device.
  • the control device outputs a status of the furnace as a result of the comparison.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Regulation And Control Of Combustion (AREA)
  • Furnace Details (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Vending Machines For Individual Products (AREA)
  • Tunnel Furnaces (AREA)

Abstract

La présente invention concerne un procédé et un dispositif de commande pour faire fonctionner un four (10), en particulier un four à anodes : le four étant formé à partir d'une pluralité de conduits de chauffage (12) et de chambres de four (13), les chambres de four servant à recevoir des produits contenant du carbone, en particulier des anodes, et les conduits de chauffage servant à réguler la température des chambres de four, le four comprenant au moins une unité de four (11). L'unité de four comprend une zone de chauffage (18), une zone de cuisson (19) et une zone de refroidissement (20), qui, pour leur part, sont formées à partir d'au moins une section (37, 38, 39, 40, 41, 42) comprenant des chambres de four, une rampe d'extraction (15) de l'unité de four est disposée dans une section de la zone de chauffage et une rampe de brûleur (16) est disposée dans une section de la zone de cuisson. L'air de traitement dans les conduits de chauffage de la zone de cuisson est chauffé au moyen de la rampe de brûleur et le gaz d'échappement provenant des conduits de chauffage de la zone de chauffage est extrait au moyen de la rampe d'extraction. Le fonctionnement des rampes est commandé au moyen d'un dispositif de commande de l'unité de four. Pour chacune d'au moins deux sections, un courant d'enthalpie est déterminé au moyen du dispositif de commande ; une différence entre les courants d'enthalpie respectifs est déterminée comme une valeur caractéristique ; la valeur caractéristique déterminée ainsi est comparée à une valeur caractéristique prédéterminée et un état du four peut être déterminé sur la base de cette comparaison.
EP21748537.4A 2020-10-28 2021-07-14 Four et procédé pour faire fonctionner un four Pending EP4237778A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020128370 2020-10-28
PCT/EP2021/069571 WO2022089796A1 (fr) 2020-10-28 2021-07-14 Four et procédé pour faire fonctionner un four

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EP4237778A1 true EP4237778A1 (fr) 2023-09-06

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EP21748537.4A Pending EP4237778A1 (fr) 2020-10-28 2021-07-14 Four et procédé pour faire fonctionner un four

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US (1) US20230400254A1 (fr)
EP (1) EP4237778A1 (fr)
AU (1) AU2021371781A1 (fr)
CA (1) CA3195549A1 (fr)
WO (1) WO2022089796A1 (fr)

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2777072B1 (fr) * 1998-04-03 2000-05-19 Pechiney Aluminium Procede et dispositif de regulation des fours de cuisson a feu tournant
FR2940417B1 (fr) * 2008-12-24 2012-11-30 Alcan Int Ltd Procede et systeme de controle du fonctionnement d'une installation de cuisson de blocs carbones.
EP2761241B1 (fr) 2011-09-29 2018-12-26 INNOVATHERM Prof. Dr. Leisenberg GmbH + Co. KG Procédé de surveillance
WO2021037622A1 (fr) * 2019-08-28 2021-03-04 Innovatherm Prof. Dr. Leisenberg Gmbh + Co. Kg Four et procédé de fonctionnement d'un four

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US20230400254A1 (en) 2023-12-14
AU2021371781A1 (en) 2023-05-25
WO2022089796A1 (fr) 2022-05-05
CA3195549A1 (fr) 2022-05-05

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