FURNACE AND METHOD FOR OPERATING A FURNACE

Abstract

The invention relates to a method and a control device for operating a furnace (10), in particular an anode furnace, the furnace being formed by a plurality of heating channels (12) and furnace chambers (13), the furnace chambers serving to receive carbonaceous products, in particular anodes, and the heating channels serving to control the temperature of the furnace chambers, the furnace comprising at least one furnace unit (11), the furnace unit comprising a heating zone (18), a fire zone (19) and a cooling zone (20), which for their part are formed by at least one section (37, 38, 39, 40, 41, 42) comprising furnace chambers, a suction ramp (15) of the furnace unit being disposed in a section of the heating zone, and a burner ramp (16) of the furnace unit being disposed in a section of the fire zone, process air in the heating channels of the fire zone being heated by means of the burner ramp, and exhaust gas being suctioned from the heating channels of the heating zone by means of the suction ramp, an operation of the ramps being controlled by means of a control device of the furnace unit. An amount of fuel of the burner ramp is determined by means of the control device, a ratio of the combustion air and the amount of fuel being determined for at least one section by means of the control device.

Claims

1. A method for operating a furnace (10), in particular an anode furnace, the furnace being formed by a plurality of heating channels (12) and furnace chambers (13), the furnace chambers serving to receive carbonaceous bodies, in particular anodes, and the heating channels serving to control the temperature of the furnace chambers, the furnace comprising at least one furnace unit (11), the furnace unit comprising a heating zone (18), a fire zone (19) and a cooling to zone (20), which for their part are formed by at least one section (37, 38, 39, 40, 41, 42) comprising furnace chambers, a suction ramp (15) of the furnace unit being disposed in a section of the heating zone, and a burner ramp (16) of the furnace unit being disposed in a section of the fire zone, process air in the heating channels of the fire zone being heated by means of the burner ramp, and exhaust gas being suctioned from the heating channels of the heating zone by means of the suction ramp, an operation of the ramps being controlled by means of a control device of the furnace unit, characterized in that an amount of fuel of the burner ramp is determined by means of the control device, a ratio of the process air and the amount of fuel being determined for at least one section by means of the control device.

2. The method according to claim 1, characterized in that a ratio of the process air and the amount of fuel is calculated for all sections (37, 38, 39, 40, 41, 42) of the heating zone (18) and/or the fire zone (19), preferably for all sections of the furnace (10), by means of the control device.

3. The method according to claim 1 or 2, characterized in that a primary amount of fuel of the burner ramp (16) is determined by means of the control device, a secondary amount of fuel of the heating zone (18) and/or the burner zone (19) being determined by means of the control device as a function of at least one chemical property of the carbonaceous bodies.

4. The method according to claim 3, characterized in that the primary amount of fuel is calculated by means of the control device as a function of a temperature measured in the heating channel (12) of the fire zone (19).

5. The method according to claim 3 or 4, characterized in that the secondary amount of fuel of the heating zone (18) is calculated as a function of a mass loss, a degree of coking and/or a temperature of the carbonaceous bodies.

6. The method according to claim 5, characterized in that the control device calculates a temperature of the carbonaceous bodies.

7. The method according to any one of claims 3 to 6, characterized in that the control device calculates a total amount of fuel from the primary amount of fuel and the secondary amount of fuel.

8. The method according to any one of claims 3 to 7, characterized in that a volumetric flow rate of the sections (37, 38, 39, 40, 41, 42) between the suction ramp (15) and the cooling ramp (17) is determined by means of the control device based on a pressure measured in the heating channel (12) or other physical parameters in the heating channel.

9. The method according to claim 8, characterized in that the volumetric flow rate in the heating channel is determined by means of the control device from a ratio of a suction capacity and the pressure in the suction ramp (15) and a ratio of the suction capacity and the pressure in the heating channel (12).

10. The method according to claim 9, characterized in that respective pressures in a plurality of heating channels (12) are correlated with the pressure in the suction ramp (15).

11. The method according to claim 8 or 9, characterized in that the suction capacity of the suction ramp (15) is determined by means of the control device by determining a valve position of a throttle valve (24) of the suction ramp.

12. The method according to any one of claims 8 to 11, characterized in that an enthalpy flow rate of the sections (37, 38, 39, 40, 41, 42) is determined by means of the control device.

13. The method according to claim 12, characterized in that a consistency of the volumetric flow rate and the enthalpy flow rate is calculated by means of the control device, potential amounts of false air of the heating channels (12) being determined based on said calculation.

14. The method according to any one of claims 8 to 13, characterized in that an amount of air introduced into the heating channels (12) and potential amounts of false air are determined by means of the control device.

15. The method according to claim 14, characterized in that a total volumetric flow rate is determined by means of the control device from the volumetric flow rate, a volumetric fuel flow rate and the amount of false air.

16. The method according to any one of claims 8 to 15, characterized in that the control device corrects the volumetric flow rate and/or the enthalpy flow rate.

17. The method according to any one of claims 8 to 16, characterized in that the volumetric flow rate, preferably of the sections (37, 38, 39, 40, 41, 42) and/or the suction ramp (15) and/or the cooling ramp (17), and/or an amount of air introduced are adjusted in such a manner by means of the control device that a target ratio of the process air and the primary amount of fuel and/or the secondary amount of fuel, preferably of the total amount of fuel, is reached, the target ratio being defined in the control device.

18. The method according to claim 17, characterized in that said adjustment takes place by a control of the volumetric flow rate at the suction ramp (15) and/or the cooling ramp (17) by means of the control device.

19. The method according to claim 17 or 18, characterized in that the primary amount of fuel introduced is adjusted in such a manner by means of the control device that a target ratio of the process air and the total amount of fuel is reached, the target ratio being defined in the control device.

20. A control device for operating a furnace (10), in particular an anode furnace, the furnace being formed by a plurality of heating channels (12) and furnace chambers (13), the furnace chambers serving to receive carbonaceous bodies, in particular anodes, and the heating channels serving to control the temperature of the furnace chambers, the furnace comprising at least one furnace unit (11), the furnace unit comprising a heating zone (18), a fire zone (19) and a cooling zone (23), which for their part are formed by at least one section (37, 38, 39, 40, 41, 42) comprising furnace chambers, a suction ramp (15) of the furnace unit being disposed in a section of the heating zone, and a burner ramp (16) of the furnace unit being disposed in a section of the fire zone, the burner ramp being configured to heat process air in the heating channels of the fire zone, and the suction ramp being configured to suction exhaust gas from the heating channels of the heating zone, the control device of the furnace unit being configured to control an operation of the ramps, characterized in that the control device is configured to determine an amount of fuel of the burner ramp, the control device being configured to determine a ratio of the process air and the amount of fuel for at least one section.

21. A furnace, in particular an anode furnace, comprising a control device according to claim 20.

Description

[0032] Hereinafter, a preferred embodiment of the invention is explained in more detail with reference to the accompanying drawings.

[0033] FIG. 1 is a schematic illustration of a furnace in a perspective view;

[0034] FIG. 2 is a schematic illustration of a furnace unit of the furnace in a longitudinal section view;

[0035] FIG. 3 shows a temperature distribution in the furnace unit;

[0036] FIG. 4 is an illustration of the furnace unit of FIG. 2 with a process diagram for an embodiment of the method for operating a furnace.

[0037] A combined view of FIGS. 1 and 2 shows a schematic illustration of an anode furnace or furnace 10 comprising a furnace unit 11. Furnace 10 has a plurality of heating channels 12, which extend parallel to each other along interposed furnace chambers 13. Furnace chambers 13 serve to accommodate anodes or carbonaceous bodies (not shown). Heating channels 12 extend in a meandering shape in the longitudinal direction of furnace 10 and have heating channel openings 14 at regular intervals, which are each covered by a heating channel cover (not shown).

[0038] Furnace unit 11 further comprises a suction ramp 15, one or multiple burner ramps 16 and a cooling ramp 17. Their positions on furnace 10 functionally define a heating zone 18, a fire zone 19 and a cooling zone 20, respectively. In the course of the production process of the anodes or carbonaceous bodies, furnace unit 11 is displaced in the longitudinal direction of furnace 10 relative to furnace chambers 13 or carbonaceous bodies by shifting suction ramp 15, burner ramps 16 and cooling ramp 17 with the result that all anodes or carbonaceous bodies located in anode furnace 10 pass through zones 18 to 20.

[0039] Suction ramp 15 is essentially formed by a collecting channel 21, which is connected to an exhaust gas cleaning system (not shown) via an annular channel 22. Collecting channel 21 for its part is connected to a heating channel opening 14 via a connecting channel 23 in each case, a throttle valve 24 being disposed on connecting channel 23 in the case at hand. Furthermore, a measuring element (not shown) for pressure measuring is disposed within collecting channel 21, and another measuring element 25 for temperature measuring is disposed in each heating channel 12 directly upstream of collecting channel 21 and is connected thereto via a data line 26. Moreover, a measuring ramp 27 comprising measuring elements 28 for each heating channel 12 is disposed in heating zone 18. A pressure and a temperature in the respective portion of heating channel 12 can be determined by means of measuring ramp 27.

[0040] Three burner ramps 16 comprising burners 30 and measuring elements 31 for each heating channel 12 are placed in fire zone 19. Burners 30 each burn a flammable fuel in heating channel 12, a burner temperature being measured by means of measuring element 31. This makes it possible for a desired burner temperature to be set in the area of fire zone 19.

[0041] Cooling zone 20 comprises cooling ramp 17, which is formed by a feeding channel 32 comprising respective connecting channels 33 and throttle valves 34 for being connected to heating channels 12. Fresh air is blown into heating channels 12 via feeding channel 32. The fresh air cools heating channels 12 or the anodes or carbonaceous bodies located in furnace chambers 13 in the area of cooling zone 20, the fresh air continuously heating up until it reaches fire zone 19. In this context, FIG. 3 shows a diagram of the temperature distribution relative to the length of heating channel 12 and zones 18 to 20. Furthermore, a measuring ramp 35 or what is referred to as a zero pressure ramp comprising measuring elements 36 is disposed in cooling zone 20. Measuring elements 36 serve to detect a pressure in respective heating channels 12. The pressure in heating channel 12 is essentially 0 in the area of measuring elements 36, a high pressure forming between measuring elements 36 and cooling ramp 17, and a low pressure forming in heating channels 12 between measuring elements 36 and suction ramp 15. Consequently, the fresh air flows from cooling ramp 17 through heating channels 12 toward suction ramp 15. Ramps 15 to 17 are each disposed in sections 37 to 42, sections 37 to 42 for their part each being formed by heating channel portions 12. Sections adjacent to sections 37 to 42 are not shown for the sake of clarity of the figure.

[0042] FIG. 4 shows furnace unit 11, which has been illustrated in FIG. 2, in connection with a process flow for operating furnace 10, the process flow being illustrated as an example. In particular, an operation of suction ramp 15, burner ramp 16 and cooling ramp 17 is controlled by means of a control device (not shown) of furnace unit 11, the control device comprising at least one means for data processing, such as a programmable logic controller or a computer, which is used to execute a computer program product or at least one software. A ratio of the process air and the amount of fuel is determined for at least one of sections 37 to 42 by means of the control device.

[0043] A primary amount of fuel of burner ramps 16 is determined by means of the control device in a method step 43. Furthermore, a temperature of the anodes or carbonaceous bodies (not shown) is calculated by means of the control device in a method step 44. This can also take place by measuring a temperature via measuring ramp 27 and/or measuring ramp 35. Furthermore, a secondary amount of fuel of heating zone 18 is calculated by means of the control device as a function of at least one chemical property of the anodes or carbonaceous bodies, in particular a temperature, in a method step 45. In a method step 46, the control device calculates a total amount of fuel from the primary amount of fuel and the secondary amount of fuel.

[0044] Furthermore, the control device calculates a volumetric flow rate in sections 37 to 42 or suction ramp 15 based on a pressure measured in heating channel 12 in a method step 47. The volumetric flow rate can be determined by the control device based on a ratio of the suction capacity and the pressure in suction ramp 15 and a ratio of the suction capacity and the pressure in heating channel 12, for example. Furthermore, an enthalpy flow rate in sections 37 to 42 is calculated in method step 47. In a method step 48, the control device determines a consistency of the volumetric flow rate and the enthalpy flow rate, potential amounts of false air in the heating channels 12 being determined by the control device based on a calculation. The control device uses potential amounts of false air to correct the volumetric flow rate in method step 47.

[0045] In method step 49, the control device calculates a ratio of an amount of air introduced or process air and the total amount of fuel from the volumetric flow rate from method step 47 and the total amount of fuel from method step 46. Furthermore, a target ratio of the process air and the total amount of fuel is defined in the control device, which means that a comparison of the ratios is drawn in method step 49. The control device now controls the volumetric flow rate at suction ramp 15 based on the comparison by adjusting throttle valve 24 by means of an actor 50 in such a manner that the desired target ratio of the process air and the amount of fuel is established. The primary amount of fuel introduced can also be controlled through the control device in order to control the ratio. Overall, this can ensure at all times that the ratio of the process air and the amount of fuel does not cause dangerous operating states; moreover, the operation of furnace 10 can be optimized.