Automatic Oven System and Oven Method

Abstract

This invention relates to a pot furnace, and more particularly to an automatic furnace drying system and method for a pot furnace used for calcining petroleum coke. It adopts a unit model, with one pot furnace constituting one unit. Each unit has four fire channels, and each fire channel corresponds to a set of flame control systems and parameter detection devices. Each set of flame control systems and parameter detection devices is connected to a CPU. The CPU controls the coordination between the flame control systems and parameter detection devices, automatically adjusting the fuel gas quantity and air-fuel ratio in the flame control system. The advantages and effects of this invention are: it achieves automatic furnace drying process control, not only replacing manual furnace drying and reducing labor requirements, but also precisely controlling the temperature fluctuation of each fire channel within the target range, preventing furnace damage, improving furnace drying stability, and significantly extending the service life of the pot furnace.

Description

Technical Field

[0001] This invention relates to a pot furnace, and more particularly to an automatic drying system and method for a pot furnace used for calcining petroleum coke, which is applied in pot furnaces used in the carbon industry for producing aluminum anodes, cathodes, electrodes, and for calcining carbon graphitized materials. Background Technology

[0002] In recent years, due to the continuous decline in electrolytic aluminum prices and the resulting surge in production costs, coupled with relatively high raw material prices, the advantages of pot furnaces in petroleum coke calcination have become more prominent, gradually gaining market share. However, in recent years, influenced by the petroleum coke market, the proportion of high-sulfur coke has increased, severely impacting the lifespan of pot furnaces. Currently, the average lifespan of pot furnaces is 4-6 years, while before the widespread use of high-sulfur coke, the lifespan was 10-12 years. This significantly shortened lifespan leads to frequent overhauls of pot furnaces. After an overhaul, the pot furnace requires a drying process upon startup, which typically takes two months.

[0003] During the furnace drying process, the temperature inside the pot furnace gradually rises, and the refractory material begins to sinter. However, the expansion of the silica bricks also increases. Therefore, furnace drying is a crucial production step for pot furnaces, directly determining their subsequent service life and lifespan. Currently, pot furnace drying in the market is done manually, following a given drying curve and using the pot furnace's expansion monitoring system. This method is not only labor-intensive, requiring multiple temperature control positions, but also prone to untimely temperature adjustments and large temperature differences in the fire channels, severely impacting the drying quality. Because pot furnace drying requires strict temperature control, manual operation cannot guarantee accurate temperature control. Therefore, a precise automatic furnace drying system needs to be developed to reduce the number of operators while ensuring effective drying. Furthermore, based on long-term experience, with an automatic furnace drying system, once the drying curve is set, the expansion monitoring system can be eliminated. Summary of the Invention

[0004] This invention provides an automatic furnace drying system and method to solve the above-mentioned problems. Its purpose is to eliminate manual operation during the start-up of newly built or overhauled pot furnaces by adopting automatic control, thereby saving manpower and significantly improving the furnace drying effect.

[0005] To achieve the above objectives, the automatic oven drying system of the present invention adopts a unit mode, with a group of pot furnaces as a unit. Each unit has four fire channels, and each fire channel corresponds to a set of flame control system and parameter detection device. Each set of flame control system and parameter detection device is connected to the CPU. The CPU controls the coordination between the flame control system and parameter detection device and automatically adjusts the amount of fuel gas and the air-fuel ratio in the flame control system.

[0006] The flame control system includes a gas system and a combustion air system. The gas system includes a burner located at the entrance of the fire channel on the first floor of the front wall. The burner is connected to a gas pipeline. Along the gas pipeline, in the direction of gas flow, are sequentially arranged a manual gas valve, a quick-cut gas valve, a slow-open gas valve, an air-fuel proportional valve, a manual regulating valve, and a mixing channel. An automatic igniter and a flame detector are installed in the mixing channel. The automatic igniter and flame detector are connected to the flame control module, which is connected to the CPU. The combustion air system includes a fan and an air pipeline connected to the fan. Along the air pipeline, in the direction of air flow, are sequentially arranged a manual butterfly valve, an electric regulating valve, and a manual ball valve. The air pipeline between the electric regulating valve and the manual ball valve is connected to one end of an air branch pipe, and the other end of the air branch pipe is connected to the air-fuel proportional valve.

[0007] The gas fast-opening valve and the gas slow-opening valve are connected to the CPU.

[0008] The parameter detection device includes a thermocouple and a pressure transmitter, which are connected to the CPU.

[0009] The thermocouples used are resistance thermometers (RTDs) with a temperature range of 0-600℃ and an accuracy of 0.1℃ up to 500℃. After 500℃, N-type or K-type thermocouples are used with a temperature range of 0-1300℃ and an accuracy of 0.1℃.

[0010] The pressure transmitter has a pressure range of -250Pa to 0 and an accuracy of 0.1Pa.

[0011] The thermocouple is installed in the first or second fire channel of the rear wall, and the pressure transmitter is installed in the sixth or eighth fire channel of the rear wall.

[0012] The CPU uses the temperature inside the flue as the control target. After the detection signal from the parameter detection device enters the CPU, it adjusts the gas system according to the temperature signal. The temperature rises according to the pre-set furnace heating curve. The opening of the gas slow-opening valve is controlled in automatic mode. If the temperature is lower than the set value, the gas slow-opening valve opens wider; if the temperature is higher than the set value, the gas slow-opening valve closes narrower. After the gas slow-opening valve is adjusted, the electric regulating valve on the air pipeline opens wider according to the opening of the gas slow-opening valve, so as to match the fixed air-fuel ratio, while the air-fuel ratio valve remains unchanged. When it is necessary to adjust the flame length and color, the size of the air-fuel ratio valve is adjusted. The gas quick-cut valve is interlocked with the pressure transmitter signal. When the pressure is lower than the set value, the gas is cut off.

[0013] Advantages and effects of the invention: The invention realizes automatic furnace drying, which can not only replace manual furnace drying and reduce the number of laborers, but also accurately control the temperature fluctuation of each fire channel within the target range, prevent furnace body damage, improve furnace drying stability, and greatly extend the service life of the tank furnace. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the single-channel automatic oven drying system of the present invention.

[0015] In the diagram: 1. Air duct; 2. Fan; 3. Manual butterfly valve; 4. Electric regulating valve; 5. Manual ball valve; 6. Burner; 7. Manual regulating valve; 8. Air-fuel proportional valve; 9. Gas slow-opening valve; 10. Gas quick-cut valve; 11. Gas manual valve; 12. Gas duct; 13. Automatic igniter; 14. Flame detector; 15. Flame control module; 16. Thermocouple; 17. Pressure transmitter; 18. CPU; 19. Fire channel; 20. Mixing channel; 21. Air branch pipe. Detailed Implementation

[0016] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments.

[0017] As shown in the figure, the automatic oven drying system of the present invention adopts a unit mode, with a group of pot furnaces as a unit. Each unit has four fire channels, and each fire channel is divided into eight layers. Each fire channel corresponds to a set of flame control system and parameter detection device. Each set of flame control system and parameter detection device is connected to CPU18. CPU18 controls the coordination between the flame control system and parameter detection device and automatically adjusts the amount of gas and air-fuel ratio in the flame control system.

[0018] The flame control system includes a gas system and a combustion air system. The gas system includes a burner 6 located at the entrance of the fire channel on the first floor of the front wall. The burner 6 is connected to a gas pipeline 12. On the gas pipeline 12, in the direction of gas flow, there are sequentially arranged a gas manual valve 11, a gas quick-cut valve 10, a gas slow-open valve 9, an air-fuel ratio valve 8, a manual regulating valve 7, and a mixing channel 20. Air and gas are mixed in the mixing channel 20. An automatic igniter 13 and a flame detector 14 are installed on the mixing channel 20. The automatic igniter 13 and the flame detector 14 are connected to the flame control module 15, and the flame control module 15 is connected to the CPU 18. The combustion air system includes a fan 2 and an air pipeline 1 connected to the fan 2. On the air pipeline 1, in the direction of air flow, there are sequentially arranged a manual butterfly valve 3, an electric regulating valve 4, and a manual ball valve 5. One end of the air pipeline 1 between the electric regulating valve 4 and the manual ball valve 5 is connected to an air branch pipe 21, and the other end of the air branch pipe 21 is connected to the air-fuel ratio valve 8. The automatic igniter 13 and flame detector 14 are integrated with the mixing channel 20.

[0019] The gas fast-opening valve 10 and the gas slow-opening valve 9 are connected to the CPU 18.

[0020] The parameter detection device includes a thermocouple 16 and a pressure transmitter 17, which are connected to a CPU 18.

[0021] The thermocouple 16 is a resistance temperature detector (RTD) with a temperature range of 0-600℃ and an accuracy of 0.1℃ before 500℃, and an N-type or K-type thermocouple with a temperature range of 0-1300℃ and an accuracy of 0.1℃ after 500℃.

[0022] The pressure transmitter 17 has a pressure range of -250Pa to 0 and an accuracy of 0.1Pa.

[0023] The thermocouple 16 is installed in the first or second fire channel of the rear wall, and the pressure transmitter 17 is installed in the sixth or eighth fire channel of the rear wall.

[0024] The automatic furnace drying system uses the CPU18 to control the temperature within the combustion chamber. Signals from the parameter detection device are input to the CPU, which then adjusts the gas system based on the temperature signal. The system heats up according to a pre-set furnace heating curve, ensuring the furnace body expands within a controllable range. In automatic mode, the opening of the slow-opening gas valve 9 is controlled. If the temperature is below the set value, the slow-opening gas valve 9 opens wider; if the temperature is above the set value, it closes less. After the slow-opening gas valve 9 is adjusted, the electric regulating valve 4 on the air pipeline opens wider to match the fixed air-fuel ratio, while the air-fuel ratio valve 8 remains unchanged. If flame length or color needs adjustment, the air-fuel ratio valve 8 is primarily adjusted. The gas quick-cut valve 10 is interlocked with the pressure transmitter 17. When the pressure falls below the set value, the gas supply is cut off to prevent a gas explosion. Manual regulating valves and manual ball valves are used to adjust the total gas or air volume, or to provide safety in case of malfunction of the electric regulating valve or the slow-opening gas valve.

Claims

1. An automatic oven drying system, characterized in that... The system adopts a unit-based design, with one set of pot-type furnaces constituting one unit. Each unit has four fire channels, and each fire channel corresponds to a set of flame control systems and parameter detection devices. Each set of flame control systems and parameter detection devices is connected to a CPU. The CPU controls the coordination between the flame control systems and parameter detection devices, automatically adjusting the gas quantity and air-fuel ratio in the flame control system. The flame control system includes a gas system and a combustion air system. The gas system includes a burner located at the inlet of the first-floor fire channel on the front wall, connected to a gas pipeline. Along the gas pipeline, in the direction of gas flow, are sequentially installed a manual gas valve, a fast-acting gas valve, a slow-acting gas valve, an air-fuel ratio valve, a manual regulating valve, and a mixing channel. An automatic igniter and a flame detector are installed in the mixing channel, connected to the flame control module. The flame control module is connected to the CPU. The combustion air system includes a fan and an air duct connected to the fan. A manual butterfly valve, an electric regulating valve, and a manual ball valve are sequentially installed on the air duct according to the airflow direction. One end of the air duct between the electric regulating valve and the manual ball valve is connected to an air branch pipe, and the other end of the air branch pipe is connected to an air-fuel proportional valve. The gas quick-opening valve and the gas slow-opening valve are connected to the CPU. The parameter detection device includes a thermocouple and a pressure transmitter, both connected to the CPU. The thermocouple is installed in the first or second-floor fire channel on the rear wall, and the pressure transmitter is installed in the sixth or eighth-floor fire channel on the rear wall. The CPU uses the temperature inside the fire channel as the control target, and the detection signal from the parameter detection device is input to the CPU. Then, the gas system is regulated by temperature signals; the temperature is increased according to the pre-set furnace heating curve, and the opening of the gas slow-opening valve is controlled in automatic mode. When the temperature is lower than the set value, the gas slow-opening valve opens wider; when the temperature is higher than the set value, the gas slow-opening valve closes narrower. After the gas slow-opening valve is regulated, the electric regulating valve on the air pipeline opens wider according to the opening of the gas slow-opening valve, so as to match the fixed air-fuel ratio, while the air-fuel ratio valve remains unchanged. When it is necessary to adjust the flame length and color, the size of the air-fuel ratio valve is adjusted. The gas quick-cut valve is interlocked with the pressure transmitter signal, and the gas is cut off when the pressure is lower than the set value.

2. The automatic oven drying system according to claim 1, characterized in that... The thermocouples used are resistance thermometers (RTDs) with a temperature range of 0-600℃ and an accuracy of 0.1℃ up to 500℃. After 500℃, N-type or K-type thermocouples are used with a temperature range of 0-1300℃ and an accuracy of 0.1℃.

3. The automatic oven drying system according to claim 1, characterized in that... The pressure transmitter has a pressure range of -250Pa to 0 and an accuracy of 0.1Pa.

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