Intelligent control method for circulating gas temperature after dry quenching heat pipe exchanger

Abstract

This invention belongs to the field of coking dry quenching production technology, specifically based on an intelligent control method for the temperature of circulating gas after the heat pipe heat exchanger in dry quenching. This method abandons the traditional method of relying on temperature detection, audible and visual alarms, and manual control of the amount of demineralized water entering the heat pipe heat exchanger. By setting a circulating gas temperature detection point after the heat pipe heat exchanger, a demineralized water flow detection point at the point of entry into the heat pipe heat exchanger, and a demineralized water flow regulating valve, a cascade regulation loop is constructed based on the PID control principle. The circulating gas temperature after the heat pipe heat exchanger is used as the main regulating parameter, and the demineralized water flow rate entering the heat pipe heat exchanger is used as the secondary regulating parameter. This achieves automatic and precise control of the demineralized water flow rate entering the heat pipe heat exchanger, effectively improving the stability of the circulating gas temperature after the heat pipe heat exchanger, reducing corrosion of pipelines and the inner wall of the dry quenching furnace, preventing tube rupture accidents, improving the safety of the production process, optimizing heat exchange efficiency, saving labor costs, and achieving a high level of automation in dry quenching production.

Description

Technical Field

[0001] This invention relates to the field of coking dry quenching production technology, specifically to a method for intelligent control of the circulating gas temperature after the dry quenching heat pipe heat exchanger. Background Technology

[0002] In the dry quenching coke production process, the circulating gas, after exchanging heat with the red-hot coke, passes sequentially through a primary dust collector, a boiler, a secondary dust collector, and a circulating fan. It then enters a heat pipe heat exchanger at a temperature of 160–180°C. Inside the heat pipe heat exchanger, it exchanges heat with demineralized water from the deaerator feedwater pump station, further recovering and utilizing the waste heat of the circulating gas. The demineralized water, after heat exchange, is then transported to the deaerator, while the temperature of the circulating gas drops to around 130°C. Maintaining the temperature of the circulating gas at 130°C after the heat pipe heat exchanger is of great significance, specifically in two aspects: Firstly, the moisture in the circulating gas reacts with the sulfur in the coke to produce corrosive substances such as sulfurous acid. Sulfurous acid is extremely corrosive at temperatures below 130°C, which can cause severe corrosion to the inner walls of pipes and dry quenching furnaces, and may even lead to pipe rupture accidents. At the same time, when the temperature of the circulating gas is below 130°C, the heat exchange efficiency will be significantly reduced, resulting in poor heat exchange efficiency and economy in production.

[0003] Secondly, if the temperature of the circulating gas after the heat pipe heat exchanger is higher than 130℃, the utilization rate of waste heat of the circulating gas will be low, and the demineralized water heated by the heat pipe heat exchanger will not meet the operating temperature requirements of the deaerator, affecting subsequent production processes.

[0004] In actual dry quenching coke production, the flow rate and temperature of the demineralized water supplied by the deoxygenated feedwater pump station often fluctuate, making it difficult to maintain a stable temperature of the circulating gas after the heat pipe heat exchanger. This has a significant adverse impact on the safety of production operations, the service life of pipelines and dry quenching furnaces, and the overall heat exchange efficiency.

[0005] Therefore, developing an intelligent circulating gas temperature control method that can stabilize the temperature of the circulating gas after the heat pipe heat exchanger at around 130℃, maximize the service life of the dry quenching furnace and pipelines, and improve the heat exchange efficiency of the circulating gas has become an urgent technical problem to be solved in the current coking dry quenching production field. Summary of the Invention

[0006] The purpose of this invention is to provide an intelligent control method for the temperature of circulating gas after the heat pipe heat exchanger in dry quenching coke. This method solves the problem that existing technologies cannot stabilize the temperature of the circulating gas after the heat pipe heat exchanger at around 130°C, which is not conducive to extending the service life of the dry quenching furnace and pipelines and preventing tube rupture accidents, and cannot improve the heat exchange efficiency of the circulating gas.

[0007] To achieve the above objectives, the present invention provides the following technical solution: Based on the intelligent control method of circulating gas temperature after dry quenching coke heat pipe heat exchanger, this method abandons the traditional approach of having the central control room notify on-site operators to manually adjust the amount of demineralized water entering the heat pipe heat exchanger. Instead, it automatically controls the opening of the demineralized water flow regulating valve entering the heat pipe heat exchanger through cascade regulation, including the following steps: Step 1: Set up a temperature detection point on the circulating gas pipeline at the outlet of the heat pipe heat exchanger to monitor the temperature of the circulating gas after the heat pipe heat exchanger in real time; set up a flow detection point on the deaerated feed water pump to the demineralized water inlet pipeline of the heat pipe heat exchanger to monitor the amount of demineralized water entering the heat pipe heat exchanger in real time. Step 2: The detected circulating gas temperature after the heat pipe heat exchanger and the amount of demineralized water entering the heat pipe heat exchanger are transmitted to the dry quenching PLC system. The system constructs a cascade regulation loop, which automatically calculates and outputs the regulation signal. Step 3: Use the regulation signal of the cascade control loop to control the opening of the demineralized water flow regulating valve entering the heat pipe heat exchanger, so as to realize the automatic regulation of the amount of demineralized water entering the heat pipe heat exchanger. This method overcomes the risks of unstable circulating gas temperature after heat pipe heat exchanger, sulfurous acid accumulation corroding pipes and the inner wall of dry quenching furnace, and even tube rupture caused by untimely manual adjustment of demineralized water volume in traditional methods. At the same time, it optimizes heat exchange efficiency, saves labor costs, and improves the level of production automation.

[0008] Furthermore, based on the characteristic that the circulating gas temperature of the heat pipe heat exchanger is affected by the amount of demineralized water from the deaerator pump station, and taking advantage of the more rapid change in flow rate, the regulation logic of the cascade control loop is optimized.

[0009] Furthermore, the specific process for optimizing the control logic of the cascade control loop is as follows: Set the amount of demineralized water entering the heat pipe heat exchanger as the regulation parameter of the secondary loop in the cascade regulation, and set the temperature of the circulating gas after the heat pipe heat exchanger as the regulation parameter of the primary loop in the cascade regulation. The dry quenching PLC system first uses a secondary loop to quickly adjust the amount of demineralized water entering the heat pipe heat exchanger, and then uses the adjustment results of the secondary loop to assist the main loop in accurately adjusting the temperature of the circulating gas after the heat pipe heat exchanger. By coordinating the regulation of the main and auxiliary loops, stable control of the circulating gas temperature after the heat pipe heat exchanger is achieved, thereby improving the efficiency of production regulation.

[0010] Furthermore, the optimal temperature of the circulating gas after the heat pipe heat exchanger is determined through multi-curve comparative analysis, thus forming a temperature optimization control scheme.

[0011] Furthermore, the analysis strategy for the temperature optimization control scheme is as follows: The temperature change of the circulating gas after the heat pipe heat exchanger is continuously recorded by the dry quenching PLC system to form a temperature change curve; at the same time, the corrosion of the pipeline and the inner wall of the dry quenching furnace is statistically analyzed over a long period of time to form a corrosion record. We collected sulfurous acid corrosion capacity curves at different temperatures and circulating gas heat exchange efficiency curves corresponding to different temperature differences. We then compared and analyzed these curves with the circulating gas temperature change curve after the heat pipe heat exchanger and the corrosion records of the pipeline and the inner wall of the dry quenching furnace. Based on the analysis results, the optimal temperature value of the circulating gas after the heat pipe heat exchanger is found that balances the pipeline corrosion protection effect with the circulating gas heat exchange efficiency. The optimal temperature value of the circulating gas after the heat pipe heat exchanger is used as the temperature control target to form a corresponding optimized control scheme.

[0012] Furthermore, by continuously and stably controlling the amount of demineralized water entering the heat pipe heat exchanger, the parameters of subsequent processes in the dry quenching coke production are stabilized. The specific process is as follows: Based on the cascade regulation method, the amount of demineralized water entering the heat pipe heat exchanger is continuously and stably automatically controlled to ensure that the amount of demineralized water entering the heat pipe heat exchanger is constant. By ensuring a stable flow of demineralized water into the heat pipe heat exchanger, the return water flow from the heat pipe heat exchanger to the deaerator is stabilized, thus ensuring the stability of various parameters of the water supplied from the deaerator to the steam drum. By relying on the stable parameters of the water supplied to the steam drum by the deaerator, the quality of steam produced by the steam drum can be improved, effectively extending the service life of the steam drum.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, by replacing the traditional manual control method, the automatic and precise adjustment of the demineralized water flow rate is achieved, which greatly improves the stability of the circulating gas temperature after the heat pipe heat exchanger, effectively reduces the corrosion of the pipeline and the inner wall of the dry quenching furnace, prevents pipe rupture accidents, and improves production safety. 2. In this invention, by optimizing the heat exchange efficiency of circulating gas, labor costs are saved, the level of automation in dry quenching coke production is improved, and the parameters of subsequent processes are stabilized, thereby improving the quality of steam produced by the steam drum and extending the service life of the steam drum, dry quenching furnace and pipelines. Attached Figure Description

[0014] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings; Figure 1 This is a schematic diagram of the overall method flow of the present invention; Figure 2 This is a timing block diagram of the intelligent control method for circulating gas temperature after the dry quenching coke heat pipe heat exchanger according to the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Reference Figure 1-2 As shown, the intelligent control method for circulating gas temperature after a dry quenching coke heat pipe heat exchanger proposed in this invention involves installing a demineralized water flow regulating valve on the demineralized water pipeline from the deaerator feedwater pump to the heat pipe heat exchanger to control the flow rate of demineralized water entering the heat pipe heat exchanger. Considering the slow response speed of PID regulation using the temperature detection point and regulating valve directly after the heat pipe heat exchanger, a flow detection device is additionally installed on the demineralized water feedwater pipeline from the deaerator feedwater pump station to the inlet of the heat pipe heat exchanger. A cascade regulation loop is constructed through the temperature detection point and the flow detection device, thereby achieving automatic and precise control of the circulating gas temperature after the heat pipe heat exchanger. Specifically, the intelligent control method of this invention mainly includes two core modules, and the specific structure and function of each module are as follows: 1. Instrumentation control and dry quenching PLC human-machine interface module: The instrument detection and control functions of this module are completed in collaboration with the detection instruments deployed on site and the dry quenching PLC system. At the hardware level, three core monitoring and control points are set up, and at the software level, the parameters are automatically adjusted by constructing a cascade regulation loop.

[0017] 1.1 Hardware monitoring and control points: (1) Temperature detection point of circulating gas after heat pipe heat exchanger: A temperature measuring instrument is installed on the circulating gas pipeline at the outlet of the heat pipe heat exchanger to measure the temperature of the circulating gas after the heat pipe heat exchanger. Since the temperature of the circulating gas at this detection point is in the range of 100 to 200℃, a Pt100 platinum resistance thermometer is selected as the temperature measuring element. Within the applicable temperature measurement range, the resistance value of the resistance thermometer corresponds one-to-one with the measured temperature. After the resistance signal is transmitted to the dry quenching PLC system in the central control room through the cable, the PLC system will calculate the actual temperature value based on the temperature-resistance curve.

[0018] (2) Demineralized water flow detection point at the heat pipe heat exchanger: A flow measuring instrument is installed at the demineralized water inlet of the heat pipe heat exchanger to measure the flow rate of the demineralized water entering the heat pipe heat exchanger; taking into account the non-conductive nature of demineralized water, an ISA-1932 standard nozzle is selected as the flow measuring component. Differential pressure transmitters are connected to the high and low pressure sides of the nozzle flow meter. The differential pressure transmitter converts the measured differential pressure value into a 4-20mA DC standard signal and transmits it to the central control room. After receiving the signal, the dry quenching PLC system first converts it back to the differential pressure value, and then calculates the actual demineralized water flow rate through a special calculation formula.

[0019] (3) Demineralized water flow regulating valve for heat pipe heat exchanger: A demineralized water flow regulating valve is installed on the demineralized water inlet pipe of the heat pipe heat exchanger. The flow rate of demineralized water entering the heat pipe heat exchanger is controlled by adjusting the opening of the valve, so as to achieve the goal of stabilizing the outlet circulating gas temperature of the heat pipe heat exchanger at around 130℃.

[0020] 1.2 Software Cascade Regulation Loop: In the dry quenching PLC system, the main controller loop is constructed using the detection data of the circulating gas temperature detection point after the heat pipe heat exchanger, and the secondary controller loop is constructed using the detection data of the demineralized water flow rate detection point entering the heat pipe heat exchanger. The temperature regulation signal output by the main controller is used as the flow rate input signal of the secondary controller. Through the coordinated regulation of the main and secondary loops, the rapid and accurate control of the amount of demineralized water entering the heat pipe heat exchanger is achieved.

[0021] 2. Optimal heat pipe heat exchanger outlet circulating gas temperature testing and pipeline corrosion protection optimization module: By continuously recording different temperature values ​​of the circulating gas at the outlet of the heat pipe heat exchanger, and simultaneously conducting statistical analysis on the corrosion of the pipeline and the inner wall of the dry quenching furnace, and taking into account the heat exchange efficiency curves of the circulating gas corresponding to different temperature differences, the optimal temperature value of the circulating gas at the outlet of the heat pipe heat exchanger that balances pipeline corrosion prevention and heat exchange efficiency is determined. This temperature value is then used as the temperature target value of the PID cascade control loop, achieving precise calibration control of the circulating gas temperature.

[0022] Furthermore, the control flow of the present invention can be referred to as follows: The circulating gas temperature (T-01) at the outlet of the heat pipe heat exchanger and the flow rate (F-01) of the deaerated feed water entering the heat pipe heat exchanger after the deaerated feed water pump are monitored in real time. The dry quenching PLC system performs numerical judgment on the detected circulating gas temperature T-01 at the outlet of the heat pipe heat exchanger. If the temperature value (i.e., T-01) is ≤115℃ or ≥140℃, the central control room will immediately issue an audible and visual alarm; if the detected value is within the normal range, it will enter the PID cascade regulation loop calculation stage. It should be noted that the lower threshold of 115℃ and the upper threshold of 140℃ are set based on the general process parameters of the dry quenching industry. 115℃ lower limit threshold: This is the critical temperature for sulfurous acid dew point corrosion of dry quenching circulating gas. Below this temperature, sulfurous acid will condense on the inner wall of the pipeline, causing a sharp increase in the corrosion rate and leading to equipment corrosion and the risk of pipe rupture. 140℃ upper limit threshold: This is the critical temperature for the waste heat utilization efficiency of the heat pipe heat exchanger. Above this temperature, waste heat recovery is insufficient, and the demineralized water cannot meet the requirements for the use of the deaerator.

[0023] The dry quenching PLC system calculates the output value of the temperature main controller loop (i.e., the T-01 controller loop) through the PID control loop, and uses this output value as the setpoint of the flow secondary controller loop (i.e., the F-01 controller loop). The flow regulator loop outputs a control signal based on the given value to control the opening of the demineralized water flow regulating valve (FV-01), thereby achieving precise regulation of the demineralized water feed rate at the inlet of the heat pipe heat exchanger. The optimal heat pipe heat exchanger outlet circulating gas temperature test and pipeline corrosion protection optimization module simultaneously conduct pipeline corrosion analysis and heat exchange efficiency calculation, providing data basis for the optimization of adjustment parameters.

[0024] Furthermore, the timing implementation process of this invention can be specifically referred to as follows: The instrumentation and control and dry quenching coke human-machine interface module serves as the core control module. It completes the acquisition of all detection data, including the temperature of the circulating gas after the heat pipe heat exchanger (T-01) and the flow rate of the demineralized water entering the heat pipe heat exchanger (F-01). At the same time, it completes the opening degree calculation of the demineralized water flow regulating valve (FV-01), control signal output, and other human-machine interface-related work. The circulating gas temperature change curve stored in the dry quenching PLC system will be transmitted to the optimal heat pipe heat exchanger outlet circulating gas temperature test and pipeline corrosion optimization module, providing data support for the analysis and calculation of this module. Process professionals regularly measure the pipe wall thickness and compare and analyze the measurement results with the circulating gas temperature change curve at the outlet of the heat pipe heat exchanger in the PLC system to obtain the optimal temperature value that balances the pipe's corrosion resistance and the circulating gas heat exchange efficiency. The system uses this optimal temperature value as the target value for PID cascade regulation, and automatically adjusts the amount of demineralized water entering the heat pipe heat exchanger through the cascade regulation loop to achieve stable control of the circulating gas temperature after the heat pipe heat exchanger.

[0025] It should be noted that the cascade control described above has advantages over manual control and single-loop PID control, such as: significantly reduced temperature fluctuation range, reduced adjustment response time from minutes to seconds, and significantly improved heat exchange efficiency, which can be referred to as follows; Temperature fluctuation: manual control ±15℃, single-loop PID ±8℃, cascade control of this application ±2℃; Response time: 5-10 minutes for manual control, 1-2 minutes for single-loop PID, and ≤10 seconds for cascade control in this application; Heat exchange efficiency: 82%–88% for conventional control, 92%–95% for this application.

[0026] The working principle of this invention is as follows: During use, a circulating gas temperature detection point is set after the heat pipe heat exchanger, and a demineralized water flow detection point and a demineralized water flow regulating valve are set at the entrance of the heat pipe heat exchanger. The detection data is transmitted to the dry quenching PLC system, constructing a PID cascade regulation loop. The circulating gas temperature is the primary regulating parameter, and the demineralized water flow is the secondary regulating parameter. The optimized logic achieves rapid flow adjustment followed by fine-tuning of the temperature. Furthermore, the optimal temperature is determined as the control target through multi-curve comparison. Over-temperature triggers an alarm, while simultaneously stabilizing the demineralized water flow to ensure parameters for subsequent processes. This replaces traditional manual control, achieving automatic and precise adjustment of the demineralized water flow, significantly improving the stability of the circulating gas temperature, mitigating corrosion of pipelines and the inner wall of the dry quenching furnace, preventing pipe rupture, optimizing heat exchange efficiency, saving labor costs, stabilizing parameters for subsequent processes, improving steam quality in the steam drum, extending the service life of related equipment, and resulting in a high level of automation and safety in dry quenching production.

[0027] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, enabling those skilled in the art to better understand and utilize it. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for intelligent control of circulating gas temperature after a dry quenching coke heat tube heat exchanger, characterized in that, Includes the following steps: Step 1: Set up a temperature detection point on the circulating gas pipeline at the outlet of the heat pipe heat exchanger to monitor the temperature of the circulating gas after the heat pipe heat exchanger in real time; set up a flow detection point on the deaerated feed water pump to the demineralized water inlet pipeline of the heat pipe heat exchanger to monitor the amount of demineralized water entering the heat pipe heat exchanger in real time. Step 2: The detected circulating gas temperature after the heat pipe heat exchanger and the amount of demineralized water entering the heat pipe heat exchanger are transmitted to the dry quenching PLC system. The system constructs a cascade regulation loop, which automatically calculates and outputs the regulation signal. Step 3: Use the regulation signal of the cascade control loop to control the opening of the demineralized water flow regulating valve entering the heat pipe heat exchanger, thereby realizing the automatic adjustment of the amount of demineralized water entering the heat pipe heat exchanger.

2. The intelligent control method for circulating gas temperature based on dry quenching coke heat pipe heat exchanger according to claim 1, characterized in that, Based on the characteristic that the circulating gas temperature of the heat pipe heat exchanger is affected by the demineralized water volume of the deaerator pump station, and taking advantage of the more rapid changes in flow rate, the control logic of the cascade control loop is optimized. The specific process of optimizing the control logic of the cascade control loop is as follows: Set the amount of demineralized water entering the heat pipe heat exchanger as the regulation parameter of the secondary loop in the cascade regulation, and set the temperature of the circulating gas after the heat pipe heat exchanger as the regulation parameter of the primary loop in the cascade regulation. The dry quenching PLC system first uses a secondary loop to quickly adjust the amount of demineralized water entering the heat pipe heat exchanger, and then uses the adjustment results of the secondary loop to assist the main loop in accurately adjusting the temperature of the circulating gas after the heat pipe heat exchanger. The temperature of the circulating gas after the heat pipe heat exchanger is stably controlled through the coordinated regulation of the main and auxiliary loops.

3. The intelligent control method for circulating gas temperature based on dry quenching coke heat pipe heat exchanger according to claim 1, characterized in that, The optimal temperature of the circulating gas after the heat pipe heat exchanger was determined by multi-curve comparative analysis, and a temperature optimization control scheme was formed.

4. The intelligent control method for circulating gas temperature based on dry quenching coke heat pipe heat exchanger according to claim 3, characterized in that, The analysis strategy for the temperature optimization control scheme is as follows: The temperature change of the circulating gas after the heat pipe heat exchanger is continuously recorded by the dry quenching PLC system to form a temperature change curve; at the same time, the corrosion of the pipeline and the inner wall of the dry quenching furnace is statistically analyzed over a long period of time to form a corrosion record. We collected sulfurous acid corrosion capacity curves at different temperatures and circulating gas heat exchange efficiency curves corresponding to different temperature differences. We then compared and analyzed these curves with the circulating gas temperature change curve after the heat pipe heat exchanger and the corrosion records of the pipeline and the inner wall of the dry quenching furnace. Based on the analysis results, the optimal temperature value of the circulating gas after the heat pipe heat exchanger is found that balances the pipeline corrosion protection effect with the circulating gas heat exchange efficiency. The optimal temperature value of the circulating gas after the heat pipe heat exchanger is used as the temperature control target to form a corresponding optimized control scheme.

5. The intelligent control method for circulating gas temperature based on dry quenching coke heat pipe heat exchanger according to claim 1, characterized in that, By continuously and stably controlling the amount of demineralized water entering the heat pipe heat exchanger, the parameters of subsequent processes in dry quenching coke production are stabilized. The specific process is as follows: Based on the cascade regulation method, the amount of demineralized water entering the heat pipe heat exchanger is continuously and stably automatically controlled to ensure that the amount of demineralized water entering the heat pipe heat exchanger is constant. By ensuring a stable flow of demineralized water into the heat pipe heat exchanger, the return water flow from the heat pipe heat exchanger to the deaerator is stabilized, thus ensuring the stability of various parameters of the water supplied from the deaerator to the steam drum. By relying on the stable parameters of the deaerator supplying water to the steam drum, the quality of steam produced by the steam drum can be improved and the service life of the steam drum can be extended.

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