A method and system for flow disturbance rejection control of a furnace outlet temperature

Abstract

This invention relates to the field of furnace temperature control technology, and more particularly to a method and system for controlling the outlet temperature of a furnace against flow disturbances. The control method includes: running a PID control loop based on the boiler drum temperature to generate a first control signal and acquiring the crude oil outlet temperature of the heat exchanger in real time; running a supervisory control logic during the heating process, generating a second control signal to forcibly reduce the heating power when the crude oil outlet temperature is higher than a first threshold; generating a third control signal to allow or forcibly increase the heating power when the crude oil outlet temperature is lower than a second threshold; the second and third control signals have higher priority than the first control signal; and outputting the highest priority control signal to the burner according to the priority. This invention can maintain the outlet temperature stable within the process target range, which is beneficial for improving the accuracy of temperature control.

Description

Technical Field

[0001] This invention relates to the field of heating furnace temperature control technology, and in particular to a method and system for controlling the outlet temperature of a heating furnace against flow disturbances. Background Technology

[0002] In industrial settings such as oil extraction and transportation, heating furnaces are one of the key pieces of equipment. Their core function is to heat crude oil to achieve the required outlet temperature (e.g., 120°C) to ensure the fluidity of the crude oil and the efficiency of subsequent processing and transportation.

[0003] The existing control systems of heating furnaces generally adopt a PID regulation scheme based on the heat exchanger outlet medium temperature / boiler drum temperature. That is, by collecting the heat exchanger outlet medium temperature / boiler drum water temperature, the output power of the heating furnace is adjusted using a PID algorithm, thereby directly or indirectly controlling the crude oil outlet temperature.

[0004] However, the crude oil flow rate of existing technologies fluctuates significantly in actual operating conditions (e.g., 100 m³ / h to 150 m³ / h). When the crude oil flow rate fluctuates between 100 m³ / h and 150 m³ / h within a few minutes, the output power of the heater adjusted using the PID algorithm cannot maintain a stable crude oil outlet temperature. In the mode of control based on the heat exchanger outlet temperature, the heater temperature or heat exchanger outlet temperature is very likely to reach the high-temperature interlock alarm and shut down. Frequent shutdowns or frequent automatic start-ups and shutdowns greatly affect the operational safety and service life of the heater. If boiler drum temperature control is used, existing PID regulation, which targets boiler drum temperature, results in low control accuracy and poor matching with process requirements. Although the principle of boiler water energy storage buffering can solve the problem of frequent start-ups and shutdowns, existing PID control schemes based on boiler drum temperature have inherent defects: when the crude oil flow rate is high (e.g., 150 m³ / h), to ensure that the outlet temperature meets the standard, the boiler drum temperature setpoint must be increased to a high level (e.g., 150℃); however, when the flow rate drops sharply (e.g., to 100 m³ / h), this fixed high setpoint will cause the crude oil outlet temperature to exceed the limit significantly. At this time, it is necessary to rely entirely on operators to manually lower the setpoint, resulting in low automation, high operational risks, and product quality fluctuations. This contradiction of 'high setpoint ensuring the lower limit, low flow rate causing overheating' is a specific technical problem that has long existed in this field and urgently needs to be solved. Summary of the Invention

[0005] To solve the above-mentioned technical problems, or at least partially solve them, the present invention provides a method and device for controlling the outlet temperature of a heating furnace against flow disturbances, which can maintain the outlet temperature stable within the process target range and improve the accuracy of temperature control.

[0006] In a first aspect, the present invention provides a method for controlling the outlet temperature of a heating furnace against flow disturbances, the heating furnace comprising a burner, a boiler drum, and a heat exchanger; the control method comprising:

[0007] A PID control loop based on the boiler drum temperature is run to generate a first control signal and to acquire the crude oil outlet temperature of the heat exchanger in real time.

[0008] The monitoring and control logic is executed such that when the crude oil outlet temperature is higher than a first threshold, a second control signal is generated to forcibly reduce the heating power; when the crude oil outlet temperature is lower than the second threshold, a third control signal is generated to allow or forcibly increase the heating power.

[0009] The second and third control signals have higher priority than the first control signal; based on the priority, the highest priority control signal is output to the burner.

[0010] In some embodiments, the supervisory control logic employs hysteresis control logic, which is as follows:

[0011] After the second control signal is output due to overheating, the output of the second control signal will only stop when the crude oil outlet temperature drops below the third threshold.

[0012] After the third control signal is output due to low temperature, the output of the third control signal will only stop when the crude oil outlet temperature rises above the fourth threshold.

[0013] The second threshold, the fourth threshold, the third threshold, and the first threshold increase sequentially.

[0014] In some embodiments, the method for controlling the outlet temperature of the heating furnace against flow disturbances further includes:

[0015] When the intervention conditions of the supervisory control logic are released and the control is transferred to the PID control loop, the output value of the PID control loop is initialized to match the actual power demand of the burner at the switching moment.

[0016] In some embodiments, the PID control loop generates the first control signal, including:

[0017] Obtain the actual temperature of the boiler drum;

[0018] Calculate the deviation between the actual temperature and the boiler drum temperature setpoint;

[0019] Based on the deviation, the first control signal is calculated and output using a PID algorithm.

[0020] In some embodiments, the method for controlling the outlet temperature of the heating furnace against flow disturbances further includes:

[0021] A status flag is set for the heating furnace based on the source of the currently active control signal.

[0022] In some embodiments, setting a status flag for the heating furnace based on the currently active control signal source includes:

[0023] When the second control signal or the third control signal is active, a first state flag is set for the heating furnace;

[0024] When the first control signal is active, a second status flag is set for the heating furnace.

[0025] In a second aspect, the present invention provides a flow disturbance-resistant control system for the outlet temperature of a heating furnace, used to implement the flow disturbance-resistant control method for the outlet temperature of a heating furnace as described in the first aspect, the control system comprising:

[0026] Temperature sensor used to monitor crude oil outlet temperature in real time;

[0027] A PID controller is used to generate a first control signal based on the boiler drum temperature;

[0028] A supervisory controller, connected to the temperature sensor, is used to generate a second or third control signal with higher priority based on the comparison result between the crude oil outlet temperature and a preset threshold.

[0029] A priority selector, connected to both the PID controller and the supervisory controller, is used to select and output the highest priority control signal to the burner.

[0030] Thirdly, the present invention also provides an electronic device, including a processor and a memory, wherein the processor executes the control method described in the first aspect by invoking a program or instructions stored in the memory.

[0031] Fourthly, the present invention also provides a storage medium that stores a program or instructions that cause a computer to perform the control method as described in the first aspect.

[0032] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0033] The anti-flow disturbance control method for the outlet temperature of a heating furnace provided in this invention includes: running a PID control loop based on the boiler drum temperature to generate a first control signal and acquiring the crude oil outlet temperature of the heat exchanger in real time; running a supervisory control logic to generate a second control signal for forcibly reducing the heating power when the crude oil outlet temperature is higher than a first threshold; and generating a third control signal for allowing or forcibly increasing the heating power when the crude oil outlet temperature is lower than a second threshold; the second and third control signals have higher priority than the first control signal; and outputting the highest priority control signal to the burner according to the priority. Thus, through a dual closed-loop architecture of "PID regulation + supervisory intervention," the method automatically adapts to fluctuations in crude oil flow (100 m³ / h ~ 150 m³ / h), maintaining the outlet temperature stable within the process target range and solving the overheating or underheating problems caused by flow changes in existing technologies. Furthermore, by directly using the crude oil outlet temperature as the core control target, the control logic is highly matched with process requirements, and the hierarchical design of the preset temperature range further improves the accuracy of temperature control. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of a flow disturbance-resistant control system for the outlet temperature of a heating furnace provided in an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0040] The flow disturbance-resistant control method for the furnace outlet temperature provided in this invention, through a dual closed-loop architecture of "PID regulation + supervisory layer intervention," automatically adapts to fluctuations in crude oil flow rate (e.g., 100 m³ / h ~ 150 m³ / h), maintaining the outlet temperature stable within the process target range. This solves the problem of overheating or underheating caused by flow rate changes in existing technologies. Furthermore, by directly using the crude oil outlet temperature as the core control target, the control logic is highly matched to process requirements, and the graded design of the preset temperature range further improves the accuracy of temperature control.

[0041] The following is an exemplary description of the method and system for controlling the outlet temperature of a heating furnace against flow disturbances provided in the embodiments of the present invention.

[0042] The heating furnace provided in this embodiment of the invention includes a burner, a boiler drum, and a heat exchanger. The burner heats the medium in the boiler drum, and the high-temperature medium heats the crude oil in the heat exchanger. The anti-flow disturbance control method for the heating furnace outlet temperature is suitable for application scenarios requiring control of the heating furnace outlet temperature. The anti-flow disturbance control method for the heating furnace outlet temperature provided in this embodiment of the invention... Figure 1 The flow disturbance-resistant control system for the outlet temperature of the heating furnace shown is implemented.

[0043] The method for controlling the outlet temperature of the heating furnace against flow disturbances includes: running a PID control loop based on the boiler drum temperature to generate a first control signal and acquiring the crude oil outlet temperature of the heat exchanger in real time; running a supervisory control logic during the heating process, generating a second control signal to forcibly reduce the heating power when the crude oil outlet temperature is higher than a first threshold; generating a third control signal to allow or forcibly increase the heating power when the crude oil outlet temperature is lower than a second threshold; the second and third control signals have higher priority than the first control signal; and outputting the highest priority control signal to the burner according to the priority.

[0044] The first control signal is output to the burner to control the burner's combustion power.

[0045] Specifically, in this embodiment, when the heating furnace is turned on, it operates a PID control loop based on the boiler drum temperature. The PID controller generates a first control signal to control the burner's combustion power to heat the boiler drum. During boiler drum heating, the boiler drum temperature changes, correspondingly affecting the crude oil outlet temperature of the heat exchanger. In subsequent heating processes, a supervisory control logic is executed, outputting the highest priority control signal to the burner based on priority.

[0046] The first and second thresholds can be set according to the target temperature of crude oil export. For example, the target export temperature can be 120°C, and then the first threshold can be set to 125°C and the second threshold to 119°C based on the target export temperature of 120°C. The following is an example of using a first threshold of 125°C and a second threshold of 119°C.

[0047] Specifically, when the crude oil outlet temperature is detected to exceed 125°C, i.e., the first threshold, the temperature is too high. At this point, the monitoring controller generates a second control signal to forcibly reduce the heating power. The second control signal is output to the burner. Since the second control signal has a higher priority than the first control signal, the second control signal is output to the burner, controlling the burner to output a set low power to heat the furnace, i.e., "heating the furnace with a low flame," in order to reduce the crude oil outlet temperature.

[0048] Specifically, when the crude oil outlet temperature is detected to be less than 119°C, i.e. the second threshold, the supervisory controller generates a third control signal to allow or force an increase in heating power. Since the third control signal has a higher priority than the first control signal, the third control signal is output to the burner to control the burner to output a set high power to heat the furnace, i.e., "heat the furnace with high heat", which can quickly increase the heating temperature of the crude oil, thereby increasing the crude oil outlet temperature.

[0049] Therefore, this embodiment of the invention, through a dual closed-loop architecture of "PID regulation + supervisory layer intervention," automatically adapts to fluctuations in crude oil flow rate (100 m³ / h ~ 150 m³ / h), maintaining the outlet temperature stable within the process target range and solving the problems of overheating or underheating caused by flow rate changes in existing technologies. Furthermore, by directly using the crude oil outlet temperature as the core control target, the control logic is highly matched to process requirements, and the tiered design of the preset temperature range further improves the accuracy of temperature control.

[0050] In some embodiments, a PID control loop based on boiler drum temperature is executed to generate a first control signal, including:

[0051] Obtain the actual temperature of the boiler drum;

[0052] Calculate the deviation between the actual temperature and the boiler drum temperature setpoint;

[0053] Based on the deviation, the first control signal is calculated and output using a PID algorithm.

[0054] Therefore, by obtaining the deviation between the actual temperature and the boiler drum temperature setpoint, the first control signal is continuously adjusted through the PID algorithm to make the actual temperature of the boiler drum equal to the boiler drum temperature setpoint, thereby ensuring that the crude oil outlet temperature is maintained at a stable value.

[0055] In some embodiments, the supervisory control logic employs hysteresis control logic, which is as follows:

[0056] After the second control signal is output due to overheating, the output of the second control signal will only stop when the crude oil outlet temperature drops below the third threshold.

[0057] After the third control signal is output due to low temperature, the output of the third control signal will only stop when the crude oil outlet temperature rises above the fourth threshold.

[0058] The second threshold, the fourth threshold, the third threshold, and the first threshold increase sequentially.

[0059] Specifically, in conjunction with the aforementioned embodiments, when the crude oil outlet temperature is detected to exceed 125°C, i.e., the first threshold, indicating excessively high temperature, the monitoring controller generates a second control signal to forcibly reduce the heating power. This control causes the burner to output a set low power to heat the furnace, i.e., "heat the furnace with a low flame," to lower the crude oil outlet temperature. When the crude oil outlet temperature drops to a third threshold, such as 124°C, the monitoring controller can be controlled to stop outputting the second control signal. At this point, since the monitoring controller stops outputting the second control signal, the first control signal is switched on to control the burner's combustion power.

[0060] Specifically, in conjunction with the aforementioned embodiments, when the detected crude oil outlet temperature is less than 119°C, i.e., the second threshold, the monitoring controller generates a third control signal to allow or force an increase in heating power. Since the third control signal has a higher priority than the first control signal, it is selected to output the third control signal to the burner, controlling the burner to output a set high power to heat the furnace, i.e., "heating the furnace at high heat," which can quickly increase the heating temperature of the crude oil, thereby increasing the crude oil outlet temperature. When the crude oil outlet temperature rises to the fourth threshold, such as 120°C, the monitoring controller can be controlled to stop outputting the third control signal. At this time, since the monitoring controller stops outputting the third control signal, the first control signal is switched to control the combustion power of the burner.

[0061] To prevent frequent switching of control modes (i.e., "oscillation") caused by slight fluctuations in outlet temperature near the threshold, this embodiment of the present disclosure introduces the above-mentioned hysteresis control logic to form a stable "dead zone" near the threshold, effectively avoiding repeated mode switching caused by measurement noise or slight disturbances, and improving system stability and actuator life.

[0062] In some embodiments, the method for controlling the outlet temperature of the heating furnace against flow disturbances further includes:

[0063] When the intervention conditions of the supervisory control logic are released and the control is transferred to the PID control loop, the output value of the PID control loop is initialized to match the actual power demand of the burner at the switching moment.

[0064] Specifically, in conjunction with the preceding embodiments, the release of the intervention condition of the supervisory control logic can be understood as the supervisory controller ceasing to output the second or third control signal. At this time, the first control signal generated by the PID controller, controlled by the PID control loop, begins to take effect, controlling the combustion power of the burner, i.e., the control of the burner is transferred to the PID control loop. When the PID control loop is in operation, to avoid power jumps caused by the mismatch between the accumulated output value (especially the integral term) of the PID controller and the current actual power when switching back from the fixed power output of the supervisory controller to the PID control loop, the present invention designs the above-mentioned bumpless switching logic.

[0065] When control is transferred to the PID control loop, since the integral term of the PID controller has been pre-set to a value that matches the current actual power, the shielding of the PID controller output is released, and the "control" is returned to the PID control loop. Since there is no sudden change in the output value, the opening of the gasifier will not jump, thus achieving "bump-free switching". This eliminates process disturbances during mode switching, ensures a smooth transition of the outlet temperature, and improves control quality and system safety.

[0066] In some embodiments, the method for controlling the outlet temperature of the heating furnace against flow disturbances further includes:

[0067] A status flag is set for the heating furnace based on the source of the currently active control signal.

[0068] This allows staff to visualize and monitor the equipment's operating status in real time, facilitating operation and maintenance management.

[0069] In some embodiments, setting a status flag for the heating furnace based on the currently active control signal source includes:

[0070] When the second control signal or the third control signal is active, a first state flag is set for the heating furnace;

[0071] When the first control signal is active, a second status flag is set for the heating furnace.

[0072] Therefore, based on the status markers, the currently active control signals of the heating furnace can be determined. By establishing a correspondence between the active control signals and the status markers of the heating furnace, staff can easily monitor the equipment's operating status in real time, facilitating operation and maintenance management.

[0073] For example, when the second control signal or the third control signal is effective, the first mark state of the heating furnace is set to S=1; when the first control signal is effective, the second mark state of the heating furnace is set to S=0.

[0074] The present invention also provides a flow disturbance-resistant control system for the outlet temperature of a heating furnace, which is used to implement the flow disturbance-resistant control method for the outlet temperature of the heating furnace as described in the above embodiments, and thus has the same or similar beneficial effects. Figure 2 A schematic diagram of a flow disturbance-resistant control system for the outlet temperature of a heating furnace provided in an embodiment of the present invention is shown below. Figure 2 As shown, the control system includes: a temperature sensor 21 for real-time monitoring of the crude oil outlet temperature; a PID controller 22 for generating a first control signal based on the boiler drum temperature; a supervisory controller 23 connected to the temperature sensor 21 for generating a second or third control signal with higher priority based on the comparison result of the crude oil outlet temperature and a preset threshold; and a priority selector 24 connected to the PID controller 22 and the supervisory controller 23 respectively for selecting and outputting the highest priority control signal to the burner.

[0075] This invention also provides a storage medium that stores a program or instructions that cause a computer to execute the flow disturbance-resistant control method for the furnace outlet temperature provided in the above embodiments.

[0076] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0077] Based on the above embodiments, this invention also provides an electronic device. Figure 2 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Figure 2As shown, the electronic device includes a processor 401 and a memory 402. The processor 401 executes the anti-flow disturbance control method for the furnace outlet temperature described in the above embodiments by calling the program or instructions stored in the memory. Therefore, it has the beneficial effects of the above embodiments, which will not be repeated here.

[0078] like Figure 2 As shown, an electronic device may include at least one processor 401, at least one memory 402, and at least one communication interface 403. The various components in the electronic device are coupled together via a bus system 404. The communication interface 403 is used for information transmission with external devices. It is understood that the bus system 404 is used to implement communication between these components. In addition to a data bus, the bus system 404 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in… Figure 2 The general designated all buses as Bus System 404.

[0079] It is understood that the memory 402 in this embodiment can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. In some embodiments, the memory 402 stores the following elements: executable units or data structures, or subsets thereof, or extended sets thereof, operating systems, and applications. In this embodiment of the invention, the processor 401 executes the steps of the various embodiments of the method provided in this embodiment of the invention by calling the programs or instructions stored in the memory 402.

[0080] The method provided in this embodiment of the invention can be applied to processor 401, or implemented by processor 401. Processor 401 can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by integrated logic circuits in the hardware of processor 401 or by instructions in software form. The processor 401 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor.

[0081] The steps of the method provided in this embodiment of the invention can be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software units in the decoding processor. The software units can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory 402, and processor 401 reads the information in memory 402 and combines it with its hardware to complete the steps of the method.

[0082] The electronic device may also include one or more physical components to execute instructions generated by the processor 401 when performing the methods provided in this embodiment of the invention. Different physical components may be located within the electronic device or outside the electronic device, such as in a cloud server. Each physical component, together with the processor 401 and the memory 402, works to realize the functions of the electronic device in this embodiment.

[0083] The terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0084] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to the specific combination of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the foregoing inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions as those in the present invention.

Claims

1. A method for controlling the outlet temperature of a heating furnace against flow disturbances, wherein the heating furnace comprises a burner, a boiler drum, and a heat exchanger; characterized in that, The control method includes: A PID control loop based on the boiler drum temperature is run to generate a first control signal and to acquire the crude oil outlet temperature of the heat exchanger in real time. During the heating process, a supervisory control logic is executed. When the crude oil outlet temperature is higher than a first threshold, a second control signal is generated to forcibly reduce the heating power; when the crude oil outlet temperature is lower than the second threshold, a third control signal is generated to allow or forcibly increase the heating power. The second and third control signals have higher priority than the first control signal; based on the priority, the highest priority control signal is output to the burner.

2. The method for controlling the outlet temperature of a heating furnace against flow disturbances according to claim 1, characterized in that, The supervisory control logic adopts hysteresis control logic, which is as follows: After the second control signal is output due to overheating, the output of the second control signal will only stop when the crude oil outlet temperature drops below the third threshold. After the third control signal is output due to low temperature, the output of the third control signal will only stop when the crude oil outlet temperature rises above the fourth threshold. The second threshold, the fourth threshold, the third threshold, and the first threshold increase sequentially.

3. The method for controlling the outlet temperature of a heating furnace against flow disturbances according to claim 1 or 2, characterized in that, Also includes: When the intervention conditions of the supervisory control logic are released and the control is transferred to the PID control loop, the output value of the PID control loop is initialized to match the actual power demand of the burner at the switching moment.

4. The method for controlling the outlet temperature of a heating furnace against flow disturbances according to claim 1, characterized in that, The PID control loop generates the first control signal, including: Obtain the actual temperature of the boiler drum; Calculate the deviation between the actual temperature and the boiler drum temperature setpoint; Based on the deviation, the first control signal is calculated and output using a PID algorithm.

5. The method for controlling the outlet temperature of a heating furnace against flow disturbances according to claim 1, characterized in that, Also includes: A status flag is set for the heating furnace based on the source of the currently active control signal.

6. The method for controlling the outlet temperature of a heating furnace against flow disturbances according to claim 1, characterized in that, Based on the currently active control signal source, set a status flag for the heating furnace, including: When the second control signal or the third control signal is active, a first state flag is set for the heating furnace; When the first control signal is active, a second status flag is set for the heating furnace.

7. A flow disturbance-resistant control system for the outlet temperature of a heating furnace, characterized in that, A method for controlling the outlet temperature of a heating furnace as described in any one of claims 1-6, wherein the control system comprises: Temperature sensor used to monitor crude oil outlet temperature in real time; A PID controller is used to generate a first control signal based on the boiler drum temperature; A supervisory controller, connected to the temperature sensor, is used to generate a second or third control signal with higher priority based on the comparison result between the crude oil outlet temperature and a preset threshold. A priority selector, connected to both the PID controller and the supervisory controller, is used to select and output the highest priority control signal to the burner.

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