Automatic control method for heating furnace burner based on burner pressure measurement

Abstract

A kind of heating furnace burner automatic control method based on single burner pressure measurement, for the slab of higher uniformity requirement of discharge temperature, install coal, air pressure real-time monitoring system at the conventional burner of soaking zone of heating furnace respectively, and the coal, air pressure data of single burner is transmitted to computer control system.According to the fluctuation of air, coal gas main and the measured value of coal, air pressure difference of current two sides single conventional burner, control system automatically judges the temperature uniformity in heating furnace, especially in soaking zone, including the uniformity of temperature in both sides and middle of furnace.According to the judgment result of temperature uniformity, automatically control corresponding burner in soaking zone.Control strategy includes automatic opening and closing of conventional burner in both sides of soaking zone, temperature setting and corresponding air-fuel ratio of flat flame burner on furnace top, so as to achieve the purpose of stable heating furnace temperature, improve the temperature uniformity of slab, reduce the energy consumption of heating furnace and realize the automatic opening and closing of burner.

Description

Technical Field

[0001] This invention belongs to the field of combustion control of metallurgical heating furnaces, and specifically relates to an automatic control method for heating furnace burners based on burner pressure measurement. Background Technology

[0002] Most hot-rolling walking beam furnaces, except for the soaking zone (the last section) which uses flat-flame burners at the top (these burners automatically adjust air and gas flow according to the set temperature), use side burners in all other heating control zones, and all are installed on the side walls. A front view of the walking beam furnace is shown below. Figure 1 Top view as follows Figure 2 .

[0003] However, the main problems that arise from long-term use of walking beam furnaces are as follows:

[0004] a) Because the gas in the gas pipeline contains a lot of impurities, the burner and pipeline will inevitably be blocked to varying degrees, thereby reducing energy efficiency, causing unstable combustion, and uneven furnace temperature.

[0005] b) Due to the different production processes of different slabs, the fluctuation of air and gas in the pressure pipeline will also result in different actual loads on different burners, which will also lead to uneven furnace temperature.

[0006] These problems seriously affect the performance of walking beam furnaces and directly impact the heating quality of slabs. To date, there is no good method to improve this problem through the flexible application of the control system.

[0007] Invention application CN201410035173.7 (filed on January 24, 2014, by Baosteel Co., Ltd.) discloses "a temperature control method for a pulse-type slab heating furnace." The key to this method is calculating the combustion time of the pulse burner based on the set furnace gas temperature and the furnace temperature detected by thermocouples. However, this method relies on the stable operation of the pulse burner valve and depends on the accuracy of the thermocouple readings within the furnace. Its effectiveness is not significant when used for slabs requiring very precise temperature differences at the furnace outlet.

[0008] Invention application CN201110359971.1 (filed on November 14, 2011, by Beijing Shougang Automation Information Technology Co., Ltd.) discloses an "Intelligent Dual-Cross Limiting Combustion Automatic Control Method for Heating Furnaces." The key to this control method is to detect the furnace temperature using thermocouples and compare it with the set furnace gas temperature, then adjust the burner flow rate to bring the actual furnace temperature closer to the set temperature. However, because this method relies too heavily on the accuracy of the thermocouple readings and neglects the uniformity of the furnace temperature, its effectiveness is not significant when dealing with slabs requiring extremely high temperature differences at the outlet. Summary of the Invention

[0009] To address the above issues and improve the temperature stability and uniformity of slab heating within the furnace, this invention provides a furnace burner control method based on individual burner pressure measurement.

[0010] Because traditional walking beam furnaces do not achieve ideal yield rates when producing slabs with high temperature uniformity requirements, this invention first monitors the gas and air pressure of the burners in the soaking zone in real time and transmits this data wirelessly to the furnace control system. Then, based on fluctuations in the air-gas pipeline, the system controls the switching on / off or temperature of the burners in the soaking zone accordingly. Simultaneously, the airflow to the burners in the soaking zone also changes in real time with the measured pressure, helping to improve the uniformity of furnace gas temperature and combustion quality, thereby improving the temperature uniformity of the slabs exiting the furnace and reducing energy consumption.

[0011] An automatic control method for furnace burners based on individual burner pressure measurement is applicable to the production of slabs with high requirements for uniform temperature at the exit of the furnace in the same batch; characterized in that:

[0012] For slabs with high requirements for uniformity of furnace exit temperature, real-time coal and air pressure monitoring systems are installed at the conventional burners in the heat soaking section of the heating furnace, which has the greatest impact on the uniformity of furnace exit temperature. The coal and air pressure data of each burner are then provided to the computer control system via wireless transmission.

[0013] Based on the fluctuations in the main gas pipe and the measured values ​​of the coal and air pressure difference between the individual conventional burners on both sides, the computer control system automatically judges the temperature uniformity in the heating furnace, especially in the soaking zone, including the temperature uniformity on both sides and in the middle of the furnace.

[0014] Based on the result of the temperature uniformity assessment, the computer control system automatically performs the following:

[0015] Switch settings for conventional burners on both sides of the heat spreader: synchronously shut off the air and gas switches of the corresponding conventional burners.

[0016] Temperature setting for the flat flame burner at the furnace top: The specific range is 20-50℃ adjustment from the current temperature, with further corresponding adjustments to the flow rate of the flat flame burner.

[0017] The corresponding air-fuel ratio is specifically the air main pressure / flow rate in the lower section of the soaking zone (side burners), thereby stabilizing the furnace temperature, improving the uniformity of the slab temperature, reducing the energy consumption of the furnace, and achieving automatic burner switching.

[0018] The automatic control method for heating furnace burners based on single burner pressure measurement according to the present invention is characterized in that the method includes the following steps:

[0019] S1: Install real-time monitoring systems for coal and air (gas and air) pressure at each conventional burner on both sides of the heating furnace soaking section;

[0020] S2: Wirelessly transmits the gas and air pressure data of a single burner to the heating furnace computer control system in real time.

[0021] S3: Determine if the flow rates in the air and gas mains fluctuate excessively;

[0022] If both the gas and air fluctuation indices fall within the corresponding first reference ranges as follows:

[0023] The first reference value for the main gas pipe is 100 Nm. 3 / h, the first reference value for the air main is 150Nm 3 / h,

[0024] Then proceed to steps S4-S7;

[0025] If either the gas or air fluctuation index is greater than the corresponding first reference value, but both are less than the corresponding second reference value:

[0026] The second reference value for the main gas pipe is 200 Nm. 3 / h, the second reference value for the air main is 300 Nm 3 / h,

[0027] To improve control stability, proceed to steps S8-S11;

[0028] If either the gas or air fluctuation index is greater than the corresponding second reference value, the pipeline fluctuation is considered too large. In order to improve control stability, the operation should be stopped and this operation plan should be terminated.

[0029] S4: Determine if the air-fuel ratio of a single burner is severely imbalanced. If it is severely imbalanced (the air-fuel ratio obtained from the actual measured air-fuel pressure of a single burner exceeds the theoretical air-fuel ratio by ±50%, the burner is considered to be no longer in normal working condition), then shut down the burner.

[0030] S5: Determine whether the difference between the gas pressure measurements of the two burners is greater than the third reference value, i.e., whether the difference between the sums of the gas pressure differences of the two burners (|∑Gas pressure difference of burner A - ∑Gas pressure difference of burner B|) is greater than the third reference value.

[0031] Multiply the rated differential pressure of the gas for a single burner by 0.9;

[0032] If the value is less than the third reference value, the S5 operation will not be performed and the process will proceed to S6. Otherwise, the computer control system will shut down 1-2 corresponding side burners based on the difference between the gas pressures of the two burners.

[0033] S6: Determine whether there is a gas pressure difference between the burners on both sides that is lower than the 4th reference value of 300Pa and higher than the 5th reference value of 20Pa. If not, no operation is performed, the S6 operation ends, and proceed to S7.

[0034] Conversely, the computer control system controls the operation mode of the intermediate flat flame burner based on the number of burners that meet the judgment conditions, that is, controls the temperature of the flat flame burner and thus controls its flow rate.

[0035] S7: If the air-fuel ratio calculated based on the air-fuel pressure measured by a single burner differs too much from the air-fuel ratio set in the main air pipe, then adjust the main air pipe pressure.

[0036] S8: Determine if the air-fuel ratio of a single burner is severely out of balance twice in a certain period of time. If so, shut down the burner and continue with this operation plan.

[0037] S9: Determine whether the sum of the gas pressure differences measured by the burners on both sides is greater than the third reference value twice in a certain period of time. The third reference value is the rated gas pressure difference of a single burner multiplied by 0.9. If so, the computer model will shut down 1-2 burners on both sides according to the sum of the gas pressure differences. If it is less than the third reference value, no operation will be performed. Operation S9 will terminate and proceed to S10.

[0038] S10: Determine whether the gas pressure difference measured by the burners on both sides is lower than the 4th reference value twice in a certain period of time (two measurement time cycles) and higher than the 5th reference value at the same time. If so, the computer model controls the operation mode of the intermediate flat flame burner according to the number of burners that meet the judgment conditions, that is, controls the temperature of the flat flame burner and thus controls its flow rate.

[0039] S11: If the air-fuel ratio calculated based on the air-fuel pressure measured by a single burner differs significantly from the air-fuel ratio set in the main air pipe (more than 30%) twice consecutively within a certain time period (two measurement time cycles), then adjust the main air pipe pressure (by 30%).

[0040] Thus, the automatic control method for the burner of the heating furnace of the present invention is basically completed.

[0041] The present invention discloses an automatic control method for a heating furnace burner based on a single burner pressure measurement, characterized in that:

[0042] In S8 and S9: The certain time period refers to two measurement time cycles, one of which is approximately 5 minutes.

[0043] The present invention discloses an automatic control method for furnace burners based on pressure measurement of a single burner.

[0044] In step S3, the volatility index is determined as follows:

[0045] Gas pipeline fluctuation index: the standard deviation of all flow data of the main gas pipeline within 10 minutes (or 8-20 minutes) (if data is collected once per minute, there will be 10 flow values ​​of the main gas pipeline in 10 minutes, and 8-20 flow values ​​of the main gas pipeline in 8-20 minutes).

[0046] Air Pipe Fluctuation Index: Similar to gas pipes, it is the standard deviation of all flow data from the main air pipe over a 10-minute period.

[0047]

[0048] in:

[0049] S – Standard deviation (volatility index)

[0050] x1,x2...x 10 —Total pipe flow data within 10 minutes,

[0051] —The average total pipe flow rate over 10 minutes,

[0052] The first reference value for the main gas pipe is 100 Nm. 3 / h, the second reference value for the main gas pipe is 200 Nm 3 / h;

[0053] The first reference value for the air main is 150 Nm. 3 / h, the second reference value for the air main is 300 Nm 3 / h.

[0054] The present invention discloses an automatic control method for a heating furnace burner based on a single burner pressure measurement, characterized in that:

[0055] In step S4, whether the air-fuel ratio of the individual burner is severely imbalanced is determined as follows:

[0056] When the actual air-fuel ratio of a single burner exceeds the theoretical air-fuel ratio by ±50%, the burner is considered to be no longer in normal working condition and is shut down.

[0057] In addition, the air-fuel ratio is calculated based on the actual measured pressure difference between gas and air, the pressure difference flow conversion formula (obtained from pipeline design parameters), fuel calorific value, and temperature, which will not be described here.

[0058] The present invention discloses an automatic control method for a heating furnace burner based on a single burner pressure measurement, characterized in that:

[0059] In step S5, whether the difference between the pressure differences of the two burners is greater than the third reference value and the control burner switch operation mode is determined as follows:

[0060] The pressure difference measured by the burner is the difference between the upstream gas / air pipeline pressure measured by a single burner (generally there are 3-4 burners on one side of the heat exchange section, symmetrical on both sides) and the downstream gas / air pipeline pressure.

[0061] The difference between the gas pressure differences of the two burners represents the difference between the sums of the gas pressure differences of the burners on different sides (|∑Gas pressure difference of burner on side A - ∑Gas pressure difference of burner on side B|).

[0062] The third reference value is the rated gas pressure difference of a single burner multiplied by 0.9 (the rated gas pressure difference of a single burner in the soaking section is generally 500 Pa).

[0063] When the gas pressure difference between the two burners is greater than the third reference value, the burner with the smallest pressure difference on the side with the larger pressure difference is shut down.

[0064] When the gas pressure difference between the two burners is greater than twice the third reference value, the burner with the second smallest pressure difference on the side with the larger pressure difference will be shut down.

[0065] The present invention discloses an automatic control method for a heating furnace burner based on a single burner pressure measurement, characterized in that:

[0066] In step S6, whether the gas pressure difference between the two burners is lower than the fourth reference value, higher than the fifth reference value, and whether the temperature of the intermediate flat flame burner is controlled are determined according to the following:

[0067] The fourth reference value is 300 Pa; the fifth reference value is 20 Pa.

[0068] The present invention discloses an automatic control method for a heating furnace burner based on a single burner pressure measurement, characterized in that:

[0069] When the gas pressure difference of a normally functioning side burner is less than the 4th reference value and greater than the 5th reference value, increase the temperature of the intermediate flat flame burner by 20°C.

[0070] When the gas pressure difference measured by two or more normally functioning side burners is less than the 4th reference value and greater than the 5th reference value, increase the temperature of the intermediate flat flame burner by 40°C.

[0071] If the burner gas pressure difference is less than the 5th reference value, the burner is considered not to be in normal working condition. Flat flame burners increase the temperature, thereby increasing the corresponding air-fuel pipeline flow rate.

[0072] Because if the gas flow rate of the side burner is too small, the burner flame will be too short, resulting in a lower furnace gas temperature in the middle of the heating furnace. The above feature is used to maintain the uniformity of the temperature of the billet exiting the furnace.

[0073] The present invention discloses an automatic control method for a heating furnace burner based on a single burner pressure measurement, characterized in that:

[0074] In step S7, the adjustment of the corresponding main flow rate based on the gas and air pressure difference measured by a single burner is determined as follows:

[0075] If the air-fuel ratio corresponding to the sum of the actual measured gas flow and air flow of all side burners in the soaking zone under normal operating conditions differs from the air-fuel ratio corresponding to the actual gas flow and air flow in the main pipe by more than 30%, then the total air pipe flow setting value of the side burners in the soaking zone should be adjusted accordingly (the total air pipe flow setting value is generally calculated based on the total gas pipe flow setting value and the theoretical air-fuel ratio).

[0076] If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total air-fuel flow rate, then the total air duct flow rate setting should be adjusted downward by 30%.

[0077] Conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total air-fuel flow rate, then the total air-fuel flow rate setting should be adjusted upward by 30%.

[0078] Otherwise, it will be considered a normal fluctuation and will not be adjusted.

[0079] According to the present invention, the total gas / air flow rate measured by a single burner is calculated as follows: First, the corresponding gas / air flow rate value of a single burner is calculated based on the gas / air pressure difference value measured by the single burner and the pressure difference flow rate conversion formula (obtained from the pipeline design parameters). The total gas / air pipeline flow rate value is obtained by summing the flow rate values ​​of all side burners under normal operating conditions in the soaking zone.

[0080] An automatic control method for furnace burners based on single burner pressure measurement according to the present invention is characterized in that:

[0081] In step S8, there are two severe misalignments within a certain time period. The certain time period refers to two measurement time cycles. Everything else is the same as in S4.

[0082] An automatic control method for furnace burners based on single burner pressure measurement according to the present invention is characterized in that:

[0083] In step S9, it is determined whether the difference between the gas pressure measured by the two burners is greater than the third reference value twice consecutively within a certain time period. The certain time period refers to two measurement time cycles. Everything else is the same as in S5.

[0084] An automatic control method for furnace burners based on single burner pressure measurement according to the present invention is characterized in that:

[0085] Step S10 involves determining whether the gas pressure difference between the two sides, where there are burners, is lower than the 4th reference value and higher than the 5th reference value twice consecutively within a certain time period. The certain time period refers to two measurement time cycles. Everything else is the same as in S6.

[0086] An automatic control method for furnace burners based on single burner pressure measurement according to the present invention is characterized in that:

[0087] The adjustment of the total flow rate in step S11 based on the gas and air pressure difference measured by a single burner is determined as follows: If the air-fuel ratio corresponding to the sum of the actual measured gas and air flow rates of all side burners in the soaking section under normal operating conditions differs from the air-fuel ratio corresponding to the actual total gas and air flow rates in the total gas and air pipes by more than 30% twice consecutively within a certain time period (two measurement time cycles), then the set value of the total air pipe flow rate for the side burners in the soaking section is adjusted accordingly. If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate is adjusted downwards by 30%; conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate is adjusted upwards by 30%. Otherwise, it is considered a normal fluctuation and no adjustment is made.

[0088] An automatic control method for furnace burners based on single burner pressure measurement according to the present invention is characterized in that:

[0089] The adjustment of the total flow rate in step S11 based on the gas and air pressure difference measured by a single burner is determined as follows: If the air-fuel ratio corresponding to the sum of the actual measured gas and air flow rates of all side burners in the soaking section under normal operating conditions differs from the air-fuel ratio corresponding to the actual total gas and air flow rates in the total gas and air pipes by more than 30% twice consecutively within a certain time period (two measurement time cycles), then the set value of the total air pipe flow rate for the side burners in the soaking section is adjusted accordingly. If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate is adjusted downwards by 30%; conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate is adjusted upwards by 30%. Otherwise, it is considered a normal fluctuation and no adjustment is made.

[0090] An automatic control method for furnace burners based on single burner pressure measurement according to the present invention is characterized in that:

[0091] The new time period mentioned in step S12 is measured again, and determined according to the following:

[0092] The new measurement time period is 5 minutes.

[0093] According to the present invention, an automatic control method for furnace burners based on individual burner pressure measurement is proposed. For slabs requiring high uniformity of outlet temperature, a real-time coal and air pressure monitoring system is installed at the conventional burners in the soaking zone of the furnace, transmitting the coal and air pressure data of each burner to a computer control system. Based on fluctuations in the main gas supply and the measured coal and air pressure difference between the individual conventional burners on both sides, the computer control system automatically determines the temperature uniformity within the furnace, especially in the soaking zone, including the uniformity of temperature on both sides and in the middle of the furnace. Based on the temperature uniformity determination, the corresponding burners in the soaking zone are automatically controlled. The control strategy includes automatic switching of conventional burners on both sides of the soaking zone, temperature setting of the flat flame burners at the furnace top, and corresponding air-fuel ratio, thereby achieving the goals of stabilizing the furnace temperature, improving the uniformity of slab outlet temperature, reducing furnace energy consumption, and automating burner switching. Attached Figure Description

[0094] Figure 1 This is a simplified front view of the walking beam furnace of the present invention.

[0095] Figure 2 This is a simplified top view of the walking beam furnace of the present invention.

[0096] Figure 3 This is a diagram showing the data transmission of burner pressure measurement data according to the present invention.

[0097] Figure 4 This is a flowchart of the control steps of the present invention.

[0098] Figure 5 for Figure 4 The corresponding operation diagram is based on the different fluctuation values ​​of the air coal main pipe. Detailed Implementation

[0099] The automatic control method for burners in the soaking section of a heating furnace according to the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0100] like Figure 4 The present invention discloses an automatic control method for furnace burners based on individual burner pressure measurement, applicable to the production of slabs requiring high uniformity of furnace exit temperature. Its key feature is that, for slabs with high uniformity of exit temperature, real-time monitoring systems for gas and air pressure are installed at the conventional burners in the soaking section of the furnace, which has the greatest impact on slab temperature uniformity. The gas and air pressure data of each individual burner are wirelessly transmitted to the computer control system. Based on fluctuations in the main gas / air pipe and the measured gas and air pressure differences between the individual conventional burners on both sides, the computer control system automatically determines the temperature uniformity within the furnace, especially in the soaking section, including the uniformity of temperature on both sides and in the middle of the furnace. Based on the temperature uniformity determination results, the computer model automatically controls the corresponding burners in the soaking section. The control strategy includes the switching on and off of conventional burners on both sides of the soaking section, the temperature setting of the flat flame burners at the furnace top, and the corresponding air-fuel ratio, thereby achieving the goals of stabilizing the furnace temperature, improving the uniformity of slab exit temperature, reducing furnace energy consumption, and automating burner switching.

[0101] Specifically, the steps are as follows:

[0102] S1: Install a real-time monitoring system for gas and air pressure at a single conventional burner on both sides of the heat exchange section of the heating furnace;

[0103] S2: Gas and air pressure data of a single burner are wirelessly transmitted in real time to the computer control system of the heating furnace.

[0104] S3: Determine if the flow rates of the air and gas mains fluctuate excessively; if the gas and air fluctuation indices are both within the corresponding first reference value range, proceed to S4-S7; if either the gas or air fluctuation index is greater than the corresponding first reference value and both are less than the corresponding second reference value, proceed to S8-S11 to improve control stability; if either the gas or air fluctuation index is greater than the corresponding second reference value, the pipeline fluctuation is considered excessive, and no operation is performed to improve control stability.

[0105] S4: Determine if the air-fuel ratio of a single burner is severely imbalanced. If severely imbalanced, shut down that burner.

[0106] S5: Determine if the sum of the gas pressure differences measured on both burners is greater than the third reference value. If it is less than the third reference value, no operation is performed; otherwise, the computer model controls the burner switch operation mode based on the sum of the gas pressure differences on both burners.

[0107] S6: Determine whether there is a gas pressure difference between the burners on both sides that is lower than the 4th reference value and higher than the 5th reference value. If not, no operation is performed. Otherwise, the computer model controls the operation mode of the intermediate flat flame burner according to the number of burners that meet the judgment conditions.

[0108] S7: Adjust the corresponding main flow rate based on the gas and air pressure difference measured by each individual burner.

[0109] S8: Determine if the air-fuel ratio of a single burner is severely imbalanced twice consecutively within a certain time period. If so, shut down the burner.

[0110] S9: Determine whether the sum of the gas pressure differences measured by the two burners exceeds the third reference value twice consecutively within a certain time period. If so, the computer model controls the burner switch operation mode based on the sum of the gas pressure differences between the two burners.

[0111] S10: Determine whether the gas pressure difference measured by the burners on both sides is lower than the 4th reference value and higher than the 5th reference value twice in a certain period of time. If so, the computer model controls the operation mode of the intermediate flat flame burner according to the number of burners that meet the judgment conditions.

[0112] S11: Adjust the corresponding main flow rate based on the air and gas pressure difference measured by each individual burner.

[0113] S12: Measure again at a new time period, repeating steps S1 to S11.

[0114] in,

[0115] The real-time gas pressure monitoring system mentioned in step S1 is determined according to the following:

[0116] At the gas pipeline monitoring points of the conventional burners on both sides of the heating furnace's soaking section, high-precision diffused silicon miniature pressure transmitters and metal pressure sensing tubes are used to collect upstream and downstream pressure signals from the orifice plate. The signal lines are then connected to a data acquisition box located nearby. Due to the high air temperature in the air pipeline, the metal pressure sensing tubes are appropriately extended, and insulation material can be added to ensure that the pressure transmitters are not damaged by the high temperature.

[0117] in,

[0118] The real-time wireless transmission of burner gas pressure data to the heating furnace computer control system, as described in step S2, is determined based on the following:

[0119] After acquiring gas and air pressure signals, the data acquisition box converts the signals and wirelessly transmits them to the data receiving box located in the control room. The data receiving box has wireless signal reception and signal conversion output functions. The data received by the data receiving box is then transmitted via wired connection to the computer control system of the nearby heating furnace. (See...) Figure 3 ).

[0120] in,

[0121] The volatility index mentioned in step S3 is determined as follows:

[0122] Gas pipeline fluctuation index: the standard deviation of all flow data of the main gas pipeline within 10 minutes (if data is collected once per minute, there will be 10 flow values ​​of the main gas pipeline in 10 minutes).

[0123] Air duct fluctuation index: Similar to gas duct, it is the standard deviation of all flow data in the main air duct within 10 minutes.

[0124]

[0125] S – Standard Deviation (Volatility Index)

[0126] x1,x2...x 10 —Total pipe flow data within 10 minutes

[0127] —Average total pipe flow rate over 10 minutes

[0128] The first reference value for the main gas pipe is 100 Nm3 / h, and the second reference value for the main gas pipe is 200 Nm3 / h.

[0129] The first reference value for the air main is 150 Nm3 / h, and the second reference value for the air main is 300 Nm3 / h.

[0130] in,

[0131] Whether the air-fuel ratio of a single burner is severely imbalanced in step S4 is determined as follows:

[0132] When the actual air-fuel ratio of a single burner exceeds the theoretical air-fuel ratio by ±50%, the burner is considered to be no longer in normal working condition and should be shut down. The air-fuel ratio is calculated based on the actual measured pressure difference between the gas and air, the pressure-to-flow conversion formula (obtained from pipeline design parameters), the fuel calorific value, and the temperature, which will not be described here.

[0133] in,

[0134] Whether the difference between the pressure differences of the two burners mentioned in step S5 is greater than the third reference value and the control burner switch operation mode is determined according to the following:

[0135] The burner pressure difference is calculated by subtracting the downstream gas / air pipeline pressure from the upstream gas / air pipeline pressure of a single burner (generally, there are 3-4 burners on one side of the soaking section, symmetrically arranged on both sides). The difference between the gas pressure differences of the burners on both sides represents the difference between the sums of the gas pressure differences of the burners on different sides (|∑A-side burner gas pressure difference - ∑B-side burner gas pressure difference|). The third reference value is the rated gas pressure difference of a single burner multiplied by 0.9 (generally, the rated gas pressure difference of a single burner in the soaking section is 500 Pa). When the difference between the gas pressure differences of the burners on both sides is greater than the third reference value, the burner with the smallest pressure difference on the side with the larger pressure difference is shut down. When the difference between the gas pressure differences of the burners on both sides is greater than twice the third reference value, the burner with the second smallest pressure difference on the side with the larger pressure difference is shut down.

[0136] in,

[0137] In step S6, whether the gas pressure difference between the two burners is lower than the fourth reference value but higher than the fifth reference value, and whether the temperature of the intermediate flat flame burner is controlled, are determined based on the following:

[0138] The fourth reference value is 300 Pa; the fifth reference value is 20 Pa.

[0139] Insufficient gas flow rate in the side burners will result in a short burner flame, leading to lower furnace gas temperature in the middle of the furnace and affecting the uniformity of the slab temperature. When the gas pressure difference of one normally functioning side burner is less than the 4th reference value but greater than the 5th reference value, the temperature of the central flat flame burner is increased by 20°C. When the gas pressure difference of two or more normally functioning side burners is less than the 4th reference value but greater than the 5th reference value, the temperature of the central flat flame burner is increased by 40°C. A burner gas pressure difference less than the 5th reference value is considered to be in an abnormal operating state.

[0140] in,

[0141] The adjustment of the total flow rate in step S7 based on the gas and air pressure difference measured by a single burner is determined as follows: When the air-fuel ratio corresponding to the sum of the actual measured gas flow and air flow of all side burners in the soaking section under normal operating conditions differs from the air-fuel ratio corresponding to the actual total gas flow and air flow by more than 30%, the total air pipeline flow rate setting value of the side burners in the soaking section is adjusted accordingly (the total air pipeline flow rate setting value is generally calculated based on the total gas pipeline flow rate setting value and the theoretical air-fuel ratio). If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total gas and air flow rate, the total air pipeline flow rate setting value is adjusted downward by 30%; conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total gas and air flow rate, the total air pipeline flow rate setting value is adjusted upward by 30%. Otherwise, it is considered a normal fluctuation and no adjustment is made.

[0142] Calculation of the total gas / air flow rate measured by a single burner: First, calculate the corresponding gas / air flow rate value of a single burner based on the gas / air pressure difference measurement and the pressure difference-flow conversion formula (obtained from pipeline design parameters). Then, sum the flow rate values ​​of all side burners under normal operating conditions in the soaking zone to obtain the total measured gas / air pipeline flow rate.

[0143] in,

[0144] The two severe misalignments mentioned in step S8 occur within a certain time period. This time period consists of two measurement time cycles. Everything else is the same as in S4.

[0145] in,

[0146] Step S9 involves determining whether the difference between the gas pressure measured by the two burners exceeds the third reference value twice consecutively within a certain time period. This certain time period consists of two measurement time cycles. Everything else is the same as in S5.

[0147] in,

[0148] Step S10 involves determining whether the gas pressure difference between the two sides, where there are burners, is lower than the 4th reference value and higher than the 5th reference value twice consecutively within a certain time period. The certain time period refers to two measurement time cycles. Everything else is the same as in S6.

[0149] in,

[0150] The adjustment of the total flow rate in step S11 based on the gas and air pressure difference measured by a single burner is determined as follows: If the air-fuel ratio corresponding to the sum of the actual measured gas and air flow rates of all side burners in the soaking section under normal operating conditions differs from the air-fuel ratio corresponding to the actual total gas and air flow rates in the total gas and air pipes by more than 30% twice consecutively within a certain time period (two measurement time cycles), then the set value of the total air pipe flow rate for the side burners in the soaking section is adjusted accordingly. If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate is adjusted downwards by 30%; conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate is adjusted upwards by 30%. Otherwise, it is considered a normal fluctuation and no adjustment is made.

[0151] in,

[0152] The new time period mentioned in step S12 is measured again, and determined according to the following:

[0153] The new measurement time period is generally 5 minutes.

[0154] Brief explanation of the principle:

[0155] Step S1: The gas and air pipeline monitoring points of the conventional burners on both sides of the heating furnace's soaking section collect upstream and downstream pressure signals from the orifice plate using high-precision diffused silicon miniature pressure transmitters. The signal lines are then connected to a data acquisition box located nearby. Due to the high air temperature in the air pipeline, the metal pressure sensing tube is appropriately extended, and insulation material can be added to ensure that the pressure transmitter is not damaged by the high temperature.

[0156] Step S2: After the data acquisition box collects the gas and air pressure signals, it converts the signals and wirelessly transmits them to the data receiving box located in the control room. The data receiving box has wireless signal reception and signal conversion output functions. The data received by the data box is then transmitted to the computer control system of the heating furnace via a wired connection.

[0157] Step S3: Determine if the pressure fluctuations in the air and gas mains are too large; if the gas and air fluctuation indices are both within the corresponding first reference value range, proceed to steps S4-S7; if either the gas or air fluctuation index is greater than the corresponding first reference value and both are less than the corresponding second reference value, proceed to steps S8-11 to improve control stability; if either the gas or air fluctuation index is greater than the corresponding second reference value, the pipeline fluctuation is considered too large, and no operation is performed to improve control stability.

[0158] The volatility index is determined as follows:

[0159] Gas pipeline fluctuation index: the standard deviation of all flow data of the main gas pipeline within 10 minutes (if data is collected once per minute, there will be 10 flow values ​​of the main gas pipeline in 10 minutes).

[0160] Air duct fluctuation index: Similar to gas duct, it is the standard deviation of all flow data in the main air duct within 10 minutes.

[0161]

[0162] S – Standard Deviation (Volatility Index)

[0163] x1,x2...x 10 —Total pipe flow data within 10 minutes

[0164] —Average total pipe flow rate over 10 minutes

[0165] The first reference value for the main gas pipe is 100 Nm3 / h, and the second reference value for the main gas pipe is 200 Nm3 / h.

[0166] The first reference value for the air main is 150 Nm3 / h, and the second reference value for the air main is 300 Nm3 / h.

[0167] Step S4: When the actual air-fuel ratio of a single burner exceeds the theoretical air-fuel ratio by ±50%, the burner is considered to be no longer in normal working condition and is shut down. The air-fuel ratio is calculated based on the actual measured pressure difference between the gas and air, the pressure difference-flow conversion formula (obtained from pipeline design parameters), the fuel calorific value, and the temperature, which will not be described here.

[0168] Step S5: Determine if the sum of the gas pressure differences between the two burners is greater than the third reference value. The burner pressure difference is the pressure of the upstream gas pipeline of a single burner minus the pressure of the downstream gas pipeline; the sum of the gas pressure differences between the two burners represents the difference between the sums of the gas pressure differences of the individual burners on both sides (|∑A-side burner gas pressure difference - ∑B-side burner gas pressure difference|). The third reference value is the rated gas pressure difference of a single burner multiplied by 0.9. If it is less than the third reference value, no operation is performed. When the sum of the gas pressure differences between the two burners is greater than the third reference value, the burner with the smallest pressure difference on the side with the larger pressure difference is shut down; when the sum of the gas pressure differences between the two burners is greater than twice the third reference value, the burner with the second smallest pressure difference on the side with the larger pressure difference is shut down.

[0169] Step S6: Determine if there is a gas pressure difference between the two burners that is lower than the 4th reference value but higher than the 5th reference value. If not, no operation is performed. Conversely, if the gas pressure difference of one normally operating side burner is lower than the 4th reference value but higher than the 5th reference value, increase the temperature of the intermediate flat flame burner by 20°C; if the gas pressure difference of two or more normally operating side burners is lower than the 4th reference value but higher than the 5th reference value, increase the temperature of the intermediate flat flame burner by 40°C. The 4th reference value is 300 Pa, and the 5th reference value is 20 Pa.

[0170] Step S7: Adjust the corresponding main flow rate based on the gas and air pressure difference measured at each burner. Determine as follows:

[0171] If the air-fuel ratio corresponding to the sum of the actual measured gas flow and air flow of all side burners in the soaking zone under normal operating conditions differs from the air-fuel ratio corresponding to the actual gas flow and air flow in the main gas pipe by more than 30%, then the set value of the total air pipe flow rate of the side burners in the soaking zone should be adjusted accordingly (the set value of the total air pipe flow rate is generally calculated based on the set value of the total gas pipe flow rate and the theoretical air-fuel ratio). If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate should be adjusted downward by 30%; conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total gas and air flow rates, then the set value of the total air pipe flow rate should be adjusted upward by 30%. Otherwise, it is considered a normal fluctuation and no adjustment is made.

[0172] Calculation of the total gas / air flow rate measured by a single burner: First, calculate the corresponding gas / air flow rate value of a single burner based on the gas / air pressure difference measurement and the pressure difference-flow conversion formula (obtained from pipeline design parameters). Then, sum the flow rate values ​​of all side burners under normal operating conditions in the soaking zone to obtain the total measured gas / air pipeline flow rate.

[0173] Step S8: Determine if the air-fuel ratio of a single burner is severely imbalanced twice consecutively within a certain time period. If so, shut down that burner. The certain time period consists of two measurement cycles. Other methods are the same as in step S4.

[0174] Step S9: Determine whether the sum of the gas pressure differences measured by the two burners exceeds the third reference value twice consecutively within a certain time period. If so, the computer model controls the burner switching operation mode based on the sum of the gas pressure differences between the two burners. The certain time period consists of two measurement time cycles. Other methods are the same as in Step 5.

[0175] Step S10: Determine if the gas pressure difference measured on both sides of the burners has been lower than the 4th reference value and higher than the 5th reference value twice consecutively within a certain time period. If so, the computer model controls the operation mode of the intermediate flat flame burner based on the number of burners that meet the judgment conditions. The certain time period consists of two measurement time cycles. Other methods are the same as in Step Six.

[0176] Step S11: If the air-fuel ratio corresponding to the sum of the actual measured gas flow rate and the sum of the actual air flow rate of all side burners in the soaking zone under normal operating conditions differs from the air-fuel ratio corresponding to the actual gas flow rate and the actual air flow rate in the main gas pipe twice within a certain time period (two measurement time cycles), then the set value of the total air pipe flow rate of the side burners in the soaking zone should be adjusted accordingly. If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total gas and air flow rate, then the set value of the total air pipe flow rate should be adjusted downward by 30%; conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total gas and air flow rate, then the set value of the total air pipe flow rate should be adjusted upward by 30%. Otherwise, it is considered a normal fluctuation and no adjustment is made.

[0177] Step S12: Take the measurement again at a new time period (usually 5 minutes), and repeat steps S1 to S11.

[0178] The above method transmits the gas pressure measured by the burners to a computer model wirelessly. The computer model obtains the pressure difference between the burners on each side of the soaking zone and the main pipe fluctuation index to determine whether the furnace temperature is uniform, thereby controlling the on / off state of the conventional burners on both sides of the soaking zone and the temperature of the flat flame burner at the furnace top. Furthermore, the air-fuel ratio can be further adjusted through burner pressure measurement. This method, through feedback from burner flow measurement data, improves the uniformity of slab temperature and burner combustion quality while reducing energy consumption.

[0179] Example 1:

[0180] Taking a hot rolling production line as an example, the control method described in this invention determines the position of the walking beam furnace in the production line (see...). Figure 1 , 2 The gas flow rate of the burners on the lower side of the soaking zone is controlled by the judgment criteria of the computer model to control the on / off state and temperature setting of the ordinary burners on both sides of the soaking zone and the flat flame burners on the furnace top.

[0181] Taking a batch of slabs with very high temperature difference requirements produced on a hot rolling production line as an example, the steps for controlling the burners in the soaking zone of the heating furnace are as follows:

[0182] At the gas pipeline monitoring point of the conventional burners (3 on each side, 6 in total) on both sides of the heating furnace soaking section, the pressure transmitter collects the upstream and downstream pressure signals of the orifice plate, and the signal line is connected to the data acquisition box next to it.

[0183] After acquiring the gas pressure signal, the data acquisition box converts the signal and wirelessly transmits it to the data receiving box located in the control room. The data received by the data receiving box is then transmitted via wired connection to the computer control system of the adjacent heating furnace. See... Figure 3 .

[0184] Table 1. Gas-air pressure difference and air-fuel ratio data for the burners on the soaking section side.

[0185]

[0186]

[0187] The gas main flow fluctuation index is 56, and the air main flow fluctuation index is 78, both of which are less than the corresponding reference values ​​and are considered normal fluctuations.

[0188] None of the six burners had a particularly imbalanced air-fuel ratio, and none exceeded the theoretical air-fuel ratio of 2.1 by more than 50%, so there was no need to shut them off.

[0189] The pressure difference between burners on side A is 1748 Pa, and the pressure difference between burners on side B is 1236 Pa. The difference between the pressure differences on both sides is 512 Pa, which is greater than the third reference value (rated pressure difference 500 Pa, third reference value 450 Pa) but less than twice the third reference value. The furnace control model shuts down burner #3 on side A, which has the lowest pressure difference.

[0190] One of the B3 burners is less than the second reference value (300 Pa) and greater than the third reference value (20 Pa). The heating furnace control model increases the temperature of the intermediate flat flame burner by 20°C.

[0191] The initial measurement calculated the total flow rate of the gas pipeline to be 3346.8 Nm³ / h, and the total flow rate of the air pipeline to be 7486.5 Nm³ / h, with a measured air-fuel ratio of 2.24. The set flow rate for the total gas pipeline is 3600 Nm³ / h, and the set flow rate for the total air pipeline is 7560 Nm³ / h, with an air-fuel ratio of 2.1. The air-fuel ratio deviation is 5.4%, less than 30%, and the main air flow rate setting does not require adjustment.

[0192] When the temperature is measured at a new time interval (5 minutes), repeat steps 1 to 7.

[0193] Example 2:

[0194] The gas main pipe flow fluctuation index is 106, and the air main pipe flow fluctuation index is 161. Both are greater than the corresponding first reference value and less than the second reference value, indicating slightly large fluctuations.

[0195] The six burners in the heat spreader section did not exceed 50% of the theoretical air-fuel ratio of 2.1 in two consecutive pressure measurements, so there was no need to shut them off.

[0196] Table 2. Gas-air pressure difference and air-fuel ratio data for the burners in the amphipathic section during two consecutive tests.

[0197]

[0198]

[0199] The first measurement showed that the pressure difference between burners on side A was 1621 Pa and the pressure difference between burners on side B was 1168 Pa. The difference between the pressure differences on both sides was 453 Pa, which is greater than the third reference value (rated pressure difference 500 Pa, the third reference value is 450 Pa) and less than twice the first reference value.

[0200] The second measurement showed that the pressure difference between the burners on side A was 1669 Pa, and the pressure difference between the burners on side B was 1197 Pa. The difference between the pressure differences on both sides was 472 Pa, which was still greater than the third reference value (rated pressure difference 500 Pa, third reference value 450 Pa), but less than twice the third reference value. The furnace control model shut down burner #2 on side A, which had the minimum pressure difference.

[0201] 4. If the burner temperature is below the second reference value (300 Pa) or above the third reference value (20 Pa), the flat flame burner temperature will not be modified.

[0202] 5. Based on the pressure difference of each burner and the corresponding pipeline pressure difference-flow conversion formula, the first measurement calculated the total gas pipeline flow rate to be 3387 Nm³ / h, the total air pipeline flow rate to be 7487 Nm³ / h, and the measured air-fuel ratio to be 2.21. The second measurement calculated the total gas pipeline flow rate to be 3439 Nm³ / h, the total air pipeline flow rate to be 7722 Nm³ / h, and the measured air-fuel ratio to be 2.25. During the first measurement, the set flow rate for the total gas pipeline was 3620 Nm³ / h, the set flow rate for the total air pipeline was 7660 Nm³ / h, and the pipeline air-fuel ratio was 2.11. During the second measurement, the set flow rate for the total gas pipeline was 3580 Nm³ / h, the set flow rate for the total air pipeline was 7430 Nm³ / h, and the pipeline air-fuel ratio to be 2.08. The air-fuel ratio deviations of 6.2% and 7.6% are both less than 30%, and the main air flow rate setting does not require adjustment.

[0203] Implementation results:

[0204] Heating furnace (see) Figure 1 , 2 Two batches of slabs of the same grade were produced, requiring extremely high uniformity of furnace exit temperature. One batch did not involve any control over the soaking zone of the heating furnace, while the other batch used the method described in this embodiment of the invention, controlling the soaking zone burners based on gas flow data from the side burners. The uniformity of slab exit temperature was significantly improved under the same tapping rhythm.

[0205] Standard production batch control:

[0206] A total of 45 slabs were produced. The average surface temperature difference of the slabs exiting the furnace (maximum detection value - minimum detection value) was 23.4℃, the tapping time was 375.6 seconds, and 15 slabs, accounting for 33.3%, met the temperature uniformity requirements.

[0207] New controlled production batch:

[0208] A total of 58 slabs were produced. The average surface temperature difference of the slabs exiting the furnace (maximum detection value - minimum detection value) was 15.6℃, the tapping time was 372 seconds, and 49 slabs, accounting for 84.5%, met the temperature uniformity requirements.

[0209] According to the present invention, an automatic control method for furnace burners based on individual burner pressure measurement is proposed. For slabs requiring high uniformity of outlet temperature, a real-time coal and air pressure monitoring system is installed at the conventional burners in the soaking zone of the furnace, transmitting the coal and air pressure data of each burner to a computer control system. Based on fluctuations in the main gas supply and the measured coal and air pressure difference between the individual conventional burners on both sides, the computer control system automatically determines the temperature uniformity within the furnace, especially in the soaking zone, including the uniformity of temperature on both sides and in the middle of the furnace. Based on the temperature uniformity determination, the corresponding burners in the soaking zone are automatically controlled. The control strategy includes automatic switching of conventional burners on both sides of the soaking zone, temperature setting of the flat flame burners at the furnace top, and corresponding air-fuel ratio, thereby achieving the goals of stabilizing the furnace temperature, improving the uniformity of slab outlet temperature, reducing furnace energy consumption, and automating burner switching.

Claims

1. An automatic control method for furnace burners based on individual burner pressure measurement, applicable to the production of slabs with high requirements for uniform temperature at the exit of the furnace in the same batch; characterized in that: The method includes the following steps: S1: Install real-time coal and air pressure monitoring systems at each conventional burner on both sides of the heating furnace's soaking section; S2: Wirelessly transmits the gas and air pressure data of a single burner to the heating furnace computer control system in real time. S3: Determine if the flow rates in the air and gas mains fluctuate excessively; If both the gas and air fluctuation indices are within the following first reference range: The first reference value for the main gas pipe is 100 Nm. 3 / h, the first reference value for the air main is 150Nm 3 / h, Then proceed to steps S4-S7; If either the gas or air fluctuation index is greater than the corresponding first reference value, but both are less than the corresponding second reference value: The second reference value for the main gas pipe is 200 Nm. 3 / h, the second reference value for the air main is 300 Nm 3 / h, To improve control stability, proceed to steps S8-S11; If either the gas or air fluctuation index is greater than the second reference value, the pipeline fluctuation is considered too large. In order to improve control stability, the operation should be stopped and this operation plan should be terminated. S4: Determine if the air-fuel ratio of a single burner is severely imbalanced. If it is severely imbalanced, shut down that burner. S5: Determine the difference between the gas pressure measurements of the two burners, that is, the difference between the sums of the gas pressure differences of the two burners on different sides, i.e., Is it greater than the third reference value? The third reference value is the rated gas pressure difference of a single burner multiplied by 0.

9. If the value is less than the third reference value, the S5 operation will not be performed and the process will proceed to S6. Otherwise, the computer control system will shut down 1-2 corresponding side burners based on the difference between the gas pressures of the two burners. S6: Determine whether there is a gas pressure difference between the burners on both sides that is lower than the 4th reference value of 300Pa and higher than the 5th reference value of 20Pa. If not, no operation is performed, the S6 operation ends, and proceed to S7. Conversely, the computer control system controls the operation mode of the intermediate flat flame burner based on the number of burners that meet the judgment conditions, that is, controls the temperature of the flat flame burner and thus controls its flow rate. S7: If the air-fuel ratio calculated based on the air-fuel pressure measured by a single burner differs too much from the air-fuel ratio set in the main air pipe, then adjust the main air pipe pressure. S8: Determine if the air-fuel ratio of a single burner is severely out of balance twice in a certain period of time. If so, shut down the burner and continue with this operation plan. S9: Determine whether the sum of the gas pressure differences measured by the burners on both sides is greater than the third reference value twice in a certain period of time. The third reference value is the rated gas pressure difference of a single burner multiplied by 0.

9. If so, the computer model will shut down 1-2 burners on both sides according to the sum of the gas pressure differences. If it is less than the third reference value, no operation will be performed. Operation S9 will terminate and proceed to S10. S10: Determine whether the gas pressure difference measured by the burners on both sides is lower than the 4th reference value twice in a certain period of time and higher than the 5th reference value at the same time. If so, the computer model controls the operation mode of the intermediate flat flame burner according to the number of burners that meet the judgment conditions, that is, controls the temperature of the flat flame burner and thus controls its flow rate. S11: If the air-fuel ratio calculated based on the air-fuel pressure measured by a single burner differs significantly from the air-fuel ratio set in the main air pipe by more than 30% twice consecutively within a certain period, then the main air pipe pressure should be adjusted by 30%. Thus, the automatic control method for the burner of the heating furnace of the present invention is basically completed.

2. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 1, characterized in that, In S8-S11: The certain time period refers to two measurement time cycles, one of which is 5 minutes.

3. The automatic control method for furnace burners based on single burner pressure measurement as described in claim 1, characterized in that, In step S4, severe misalignment means that when the air-fuel ratio obtained from the actual measured air-fuel pressure of a single burner exceeds the theoretical air-fuel ratio by ±50%, the burner is considered to be no longer in normal working condition.

4. The automatic control method for furnace burners based on single burner pressure measurement as described in claim 1, characterized in that, In step S3, the volatility index is determined as follows: Gas pipeline fluctuation index: The standard deviation of all flow data of the main gas pipeline within 8-20 minutes. If the data is collected once per minute, there will be 8-20 flow values ​​of the main gas pipeline within 8-20 minutes. Air duct fluctuation index: Similar to gas duct, the standard deviation of all flow data in the main air duct over 8-20 minutes.

5. The automatic control method for furnace burners based on single burner pressure measurement as described in claim 4, characterized in that, In step S3, the volatility index is determined as follows: Gas pipeline fluctuation index: The standard deviation of all flow data of the main gas pipeline within 10 minutes; if data is collected once per minute, there will be 10 flow values ​​of the main gas pipeline in 10 minutes. Air Pipe Fluctuation Index: Similar to gas pipes, it is the standard deviation of all flow data from the main air pipe over a 10-minute period. ， in: S—Standard deviation —Total pipe flow data within 10 minutes, —The average total pipe flow rate over 10 minutes, The first reference value for the main gas pipe is 100 Nm. 3 / h, the second reference value for the main gas pipe is 200 Nm 3 / h; The first reference value for the air main is 150 Nm. 3 / h, the second reference value for the air main is 300 Nm 3 / h.

6. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 1, characterized in that, In step S5, whether the difference between the pressure differences of the two burners is greater than the third reference value and the control burner switch operation mode is determined as follows: The burner pressure difference is the difference between the upstream gas / air pipeline pressure measured for a single burner and the downstream gas / air pipeline pressure. The difference between the gas pressure differences of the two burners represents the difference between the sums of the gas pressure differences of the two burners on different sides; The third reference value is 0.9 times the rated gas pressure difference of a single burner, and the rated gas pressure difference of a single burner in the soaking zone is 500 Pa. When the gas pressure difference between the two burners is greater than the third reference value, the burner with the smallest pressure difference on the side with the larger pressure difference is shut down. When the gas pressure difference between the two burners is greater than twice the third reference value, the burner with the second smallest pressure difference on the side with the larger pressure difference will be shut off.

7. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 1, characterized in that: In step S6, whether the gas pressure difference between the two burners is lower than the fourth reference value, higher than the fifth reference value, and whether the temperature of the intermediate flat flame burner is controlled are determined according to the following: The fourth reference value is 300 Pa; the fifth reference value is 20 Pa. When the gas pressure difference of a normally functioning side burner is less than the 4th reference value and greater than the 5th reference value, increase the temperature of the intermediate flat flame burner by 20°C. When the gas pressure difference measured by two or more normally functioning side burners is less than the 4th reference value and greater than the 5th reference value, increase the temperature of the intermediate flat flame burner by 40°C. If the gas pressure difference between the burner and the burner is less than the fifth reference value, the burner is considered to be not in normal working condition.

8. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 1, characterized in that: In step S7, the adjustment of the corresponding main flow rate based on the gas and air pressure difference measured by a single burner is determined as follows: If the air-fuel ratio corresponding to the sum of the actual measured gas flow and air flow of all side burners in the heat-soaking section under normal working conditions differs from the air-fuel ratio corresponding to the actual gas flow and air flow in the main gas pipe by more than 30%, then the set value of the total air pipe flow of the side burners in the heat-soaking section should be adjusted accordingly. If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total air-fuel flow rate, then the total air duct flow rate setting should be adjusted downward by 30%. Conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total air flow rate, then the total air duct flow rate setting should be adjusted upwards by 30%. Otherwise, it will be considered a normal fluctuation and will not be adjusted.

9. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 7, characterized in that: The total air duct flow rate setpoint is generally calculated based on the total gas duct flow rate setpoint and the theoretical air-fuel ratio.

10. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 1, characterized in that: Calculation of the total gas / air flow rate measured by a single burner: First, calculate the corresponding gas / air flow rate value of a single burner based on the gas / air pressure difference value and the pressure difference flow rate conversion formula. Then, add up the gas / air flow rate values ​​of all side burners under normal operating conditions in the heat exchange section to obtain the total gas / air pipeline flow rate value.

11. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 1, characterized in that: In step S10, the determination of whether there is a gas pressure difference between the two sides of the burner is lower than the 4th reference value and higher than the 5th reference value twice in a certain period of time. The certain period of time refers to two measurement time cycles.

12. The automatic control method for a heating furnace burner based on single burner pressure measurement as described in claim 1, characterized in that: The adjustment of the corresponding total pipe flow rate based on the gas and air pressure difference measured by a single burner in step S11 is determined as follows: when the air-fuel ratio corresponding to the sum of the actual measured gas flow rate and the sum of the air flow rate of all side burners in the soaking section under normal working conditions is greater than 30% twice in a certain period of time compared with the air-fuel ratio corresponding to the actual total gas pipe flow rate and the total air pipe flow rate, the set value of the total air pipe flow rate of the side burners in the soaking section is adjusted accordingly. If the air-fuel ratio measured by a single burner is more than 30% greater than the air-fuel ratio calculated by the total air-fuel flow rate, the total air-fuel flow rate setting should be adjusted downwards by 30%. Conversely, if the air-fuel ratio measured by a single burner is more than 30% less than the air-fuel ratio calculated by the total air-fuel flow rate, the total air-fuel flow rate setting should be adjusted upwards by 30%. Otherwise, it is considered a normal fluctuation and no adjustment is made.

Images