Shaft furnace gas supply pipe network pressure multi-point sampling control system and application thereof

Abstract

The invention relates to the technical field of electrical automation, in particular to a multipoint sampling control system for pressure of a shaft furnace gas supply pipe network and application of the multipoint sampling control system. The interlocking action deviation of gas system equipment is extremely large; and the overall safety and efficiency of gas supply of the shaft furnace are finally influenced. Data acquisition, electric transmission and PLC control are combined, multi-point sampling is utilized, interlocking control and protection of multiple alternative shaft furnace reducing gas and heating gas quick-break valves are achieved through PLC control system program logic control, the influence of interlocking misoperation of gas system equipment and safety risks caused by single-point sampling abnormity are effectively eradicated, and the safety and reliability of the gas system equipment are improved. Great support is provided for multi-point pressure sampling of a shaft furnace gas supply pipe network, the accuracy, reliability and safety of shaft furnace gas interlocking cut-off are effectively improved, and the influence of unreal pressure measurement of mixed gas entering the shaft furnace and faults of a different-place and different-station control system on production and operation of the shaft furnace is avoided.

Description

Technical Field

[0001] This invention relates to the field of electrical automation technology, specifically to a multi-point sampling control system for the pressure of vertical furnace gas supply pipelines and its application. Background Technology

[0002] Currently, the gas pressure control system for the secondary vertical shaft furnace uses single-point sampling for raw gas. Pressure is detected by the control system of the No. 5 gas pressurization station at the power plant, located 1 km away. The No. 5 pressurization station's PLC control system then transmits the pressure detection signal via industrial Ethernet to the No. 1 PLC control station of the vertical shaft furnace PLC control system to obtain the gas pressure signal. A pressure-locked interlocking logic is established with the reducing gas and heating gas quick-stop valves of multiple vertical shaft furnaces. When the gas pressure detection value is below 3 kPa, the inlet quick-stop valves of the reducing gas and heating gas in multiple vertical shaft furnaces are interlocked and closed to prevent backfire and other gas-related safety issues. There are three shortcomings in using the gas pressure signal collected from the mixed gas main pipe of the No. 5 pressurization station compressor as the interlocking condition for the quick-closing valve at the vertical furnace gas inlet: First, the pressure of the mixed gas changes during its 1km transport through the main pipe due to factors such as pipeline conditions and ambient temperature, failing to accurately reflect the pressure at the vertical furnace gas inlet. Second, the PLC control system of the No. 5 pressurization station is under the supervision of the power plant and is relatively independent of the concentrator, meaning its equipment operation and control system status cannot be promptly fed back to the concentrator. Third, the pressure signal collected by the No. 5 pressurization station PLC control system is transmitted to the vertical furnace PLC system via the MESSAGE transmission command of the industrial Ethernet AB control system. This involves a long industrial network route, requiring signal transmission across the PLC control system, and presents multiple points of failure or damage in equipment hardware, industrial network communication, and instrumentation. In severe cases, this could lead to the simultaneous shutdown of 18 vertical furnaces, affecting not only the secondary beneficiation process output but also posing significant safety risks and hidden dangers. Summary of the Invention

[0003] This invention provides a multi-point sampling control system for the pressure of a vertical shaft furnace gas supply pipeline and its application, in order to solve the problems mentioned above.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: The multi-point sampling control system for the vertical shaft furnace gas supply pipeline pressure includes a steelmaking power plant. The power plant is equipped with a coking coal press and a high-efficiency coal press, and also has a fifth pressurization PLC control station. The coking coal press and high-efficiency coal press are connected to multiple vertical shaft furnaces located within the steelmaking ore dressing plant. Between the coking coal press, the high-efficiency coal press, and the vertical shaft furnaces, there are sequentially arranged pressure sampling points P0, P1, P2, and P3 for the mixed gas main pipeline of the original fifth pressurization station. P1 is connected to the vertical shaft furnace #1 PLC control station, P2 is connected to the vertical shaft furnace #3 PLC control station, and P3 is connected to the vertical shaft furnace #5 PLC control station.

[0005] The application of a multi-point sampling control system for the pressure of the vertical shaft furnace gas supply network includes the following steps: Step 1: First, set up three sampling points in sequence at the mixed gas main pipe near the multiple vertical furnaces in the secondary vertical furnace production area: mixed gas main pipe pressure sampling point P1, mixed gas main pipe pressure sampling point P2, and mixed gas main pipe pressure sampling point P3. All three pressure sampling points use pressure gauges and data cables for measurement and signal transmission.

[0006] Step 2: Send the mixed gas main pipe pressure sampling point P1 to the vertical furnace 1# PLC control station, the mixed gas main pipe pressure sampling point P2 to the vertical furnace 3# PLC control station, and the mixed gas main pipe pressure sampling point P3 to the vertical furnace 5# PLC control station. The vertical furnace 1# PLC control station, the vertical furnace 3# PLC control station, and the vertical furnace 5# PLC control station realize the interlocking data sharing of the entire vertical furnace PLC control system through the MESSAGE instruction.

[0007] Step 3: The pressure values ​​of three sampling points (P1, P2, and P3) in the mixed gas main pipe are arbitrarily selected and compared using the five-pressure PLC control station. The data from the forced stop control program of the "three-out-of-two" interlock protection of the reducing gas shut-off valve is used as the basis for the interlock control of the reducing gas quick-stop valves of multiple vertical furnaces. The data from the forced stop control program of the "three-out-of-two" interlock protection of the heating gas shut-off valve is used as the basis for the interlock control of the heating gas quick-stop valves of multiple vertical furnaces. When two of the pressure points are both <3kPa, the pressure of the mixed gas main pipe does not meet the gas supply pressure requirements of the vertical furnace. At this time, the five-pressure PLC control station controls the closure of the gas quick-stop valve.

[0008] The present invention has the following beneficial effects: This invention improves the accuracy, reliability, and safety of the vertical furnace gas interlocking cutoff by changing remote single-point sampling to near-point multi-point sampling. The sampling information is directly collected, processed, and executed by the vertical furnace PLC control station. It completely eliminates the impact of inaccurate pressure measurement of mixed gas entering the vertical furnace and the failure of remote control systems on the production and operation of the vertical furnace, providing a reliable guarantee for the safe production of the secondary vertical furnace.

[0009] In the sampling design stage of the vertical furnace mixed gas main pipe of the present invention, computational fluid dynamics (CFD) is used to simulate the flow field inside the gas pipeline. The sampling point location is determined according to the flow field distribution characteristics, so that the sampling point can more accurately reflect the real gas pressure and avoid sampling deviation caused by local eddies and uneven flow velocity in the vertical furnace mixed gas main pipe sampling.

[0010] The present invention applies a multi-sampling point scheme in the sampling modification of the vertical furnace mixed gas main pipe. Based on different operating conditions, pipeline operation time or equipment aging of the vertical furnace mixed gas main pipe sampling, the sampling point locations and the number of sampling points are reasonably selected to determine the actual pressure of the vertical furnace mixed gas main pipe sampling pipeline through multi-point sampling.

[0011] The sampling point of the mixed gas main pipe of the vertical furnace of the present invention adopts a high-precision and high-sensitivity pressure sensor, which can more accurately measure the minute changes in the pressure of the mixed gas main pipe of the vertical furnace, improve the accuracy of the sampling data, and at the same time, the high-precision pressure sensor has good anti-interference ability and stability, reducing the influence of external factors on the sampling measurement results of the mixed gas main pipe of the vertical furnace.

[0012] The pressure acquisition method for the mixed gas main pipe of the vertical furnace in this invention adopts a specially structured sampling probe with a filter device to prevent impurities and dust in the gas from clogging the sampling port, ensuring the continuity and reliability of sampling. At the same time, it can more realistically and accurately reflect the gas pressure entering the vertical furnace, ensuring the validity of the original value of the pressure signal of the vertical furnace PLC control system.

[0013] This invention collects the pressure on the mixed gas main pipe near the vertical furnace and transmits it via the vertical furnace PLC control station. This avoids long-distance cross-station signal transmission via Ethernet, ensuring rapid response between the status of on-site facilities and central control commands. Furthermore, through PLC logic control, any two of the three pressure values ​​can be used as real-time criteria for interlocking the instantaneous shut-off valve, enhancing the reliability and safety of the pressure data acquisition, transmission, and processing process. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating the modification of the multi-point sampling system for gas pipeline pressure in this invention.

[0015] Figure 2 This is a flowchart of the multi-point sampling and interlocking control program for the vertical furnace gas pipeline pressure in this invention.

[0016] The meanings of the reference numerals in the attached figures are as follows: 1. Pressure sampling point P0 of the mixed gas main pipe at the original No. 5 pressurization station; 2. Pressure sampling point P1 of the mixed gas main pipe; 3. Pressure sampling point P2 of the mixed gas main pipe; 4. Pressure sampling point P3 of the mixed gas main pipe; 5. PLC control station of vertical furnace No. 1; 6. PLC control station of vertical furnace No. 3; 7. PLC control station of vertical furnace No. 5; 8. Forced stop control program for the "three-out-of-two" interlock protection of the reducing gas shut-off valve; 9. Forced stop control program for the "three-out-of-two" interlock protection of the heating gas shut-off valve; 10. Steelmaking power plant; 11. Coking coal pressurizer; 12. High-pressure coal pressurizer; 13. No. 5 pressurization PLC control station; 14. Steelmaking ore dressing plant; 15. Vertical furnace. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0018] The multi-point sampling control system for the pressure of the vertical furnace gas supply pipeline includes a steelmaking power plant 10. The steelmaking power plant 10 is equipped with a coking coal press 11 and a high-efficiency coal press 12. The steelmaking power plant 10 is also equipped with a five-pressurization PLC control station 13. The coking coal press 11 and the high-efficiency coal press 12 are connected to multiple vertical furnaces 15 located in the steelmaking ore dressing plant 14. Between the coking coal press 11 and the high-efficiency coal press 12 and the vertical furnace 15, there are sequentially arranged pressure sampling points P0-1, P1-2, P2-3 and P3-4 of the mixed gas main pipeline of the original five-pressurization station. The mixed gas main pipeline pressure sampling point P1-2 is connected to the vertical furnace 1# PLC control station 5, the mixed gas main pipeline pressure sampling point P2-3 is connected to the vertical furnace 3# PLC control station 6, and the mixed gas main pipeline pressure sampling point P3-4 is connected to the vertical furnace 5# PLC control station 7.

[0019] In practical applications, for problems such as pressure detection and signal transmission in the vertical furnace gas supply system, on-site fault statistics and analysis are conducted, and improvement plans for pressure detection and transmission in the vertical furnace gas supply system are formulated and implemented to achieve real-time monitoring, effective transmission and control of the pressure in the vertical furnace gas supply system.

[0020] First, three sampling points, namely P1(2), P2(3), and P3(4), are set up in sequence at the mixed gas main pipe near the 18 vertical furnaces (15) in the second vertical furnace production area. The sampling points are 0.1km away from the vertical furnaces. Pressure gauges and data cables are used to measure and transmit signals at the three pressure sampling points, namely P1(2), P2(3), and P3(4).

[0021] The mixed gas main pipe pressure sampling point P1 (2) is sent to the vertical furnace 1# PLC control station (5), the mixed gas main pipe pressure sampling point P2 (3) is sent to the vertical furnace 3# PLC control station (6), and the mixed gas main pipe pressure sampling point P3 (4) is sent to the vertical furnace 5# PLC control station (7). The vertical furnace 1# PLC control station (5), the vertical furnace 3# PLC control station (6) and the vertical furnace 5# PLC control station (7) realize the interlocking data sharing of the entire vertical furnace PLC control system through the MESSAGE instruction.

[0022] Because the process environment and equipment conditions at the production site change in real time, various factors such as vibration and corrosion may cause the signal lines of the detection elements to break, resulting in sudden pressure changes at a single point and equipment malfunction, causing 18 vertical furnaces (15) to be interlocked and shut down. Therefore, the logic algorithm of the PLC control system is used to compare and judge the pressure values ​​of the three sampling points by taking any two values.

[0023] The pressure values ​​of three sampling points, namely P1 (2), P2 (3), and P3 (4), of the mixed gas main pipe are arbitrarily selected and compared by the five-pressure PLC control station (13). The data from the "three-out-of-two" interlocking protection forced stop control program (8) of the reducing gas shut-off valve is used as the basis for the interlocking control of the reducing gas quick-stop valve of multiple vertical furnaces (15). The data from the "three-out-of-two" interlocking protection forced stop control program (9) of the heating gas shut-off valve is used as the basis for the interlocking control of multiple vertical furnaces (15). The interlock control basis of the heating gas quick-cut valve of the vertical furnace (15) is that when two of the pressure points are <3kPa, the pressure of the mixed gas main pipe does not meet the gas supply pressure requirements of the vertical furnace. At this time, the five-pressurization PLC control station (13) controls the gas quick-cut valve to close, thereby realizing the gas cut-off protection of the vertical furnace, effectively improving the safety of the vertical furnace gas quick-cut valve interlock, providing a safety guarantee for the stable production of the vertical furnace, and effectively preventing the accidental shutdown caused by single-point pressure interference, thereby greatly ensuring the overall efficiency of the vertical furnace gas supply.

Claims

1. A vertical furnace gas supply pipe network pressure multi-point sampling control system, comprising a steelmaking power plant (10), wherein a coke coal pressurizing machine (11) and a high coal pressurizing machine (12) are arranged in the steelmaking power plant (10), and five pressurizing PLC control stations (13) are further arranged in the steelmaking power plant (10), the coke coal pressurizing machine (11) and the high coal pressurizing machine (12) are connected to a plurality of vertical furnaces (15) located in a steelmaking concentrator (14), and the vertical furnace gas supply pipe network pressure multi-point sampling control system is characterized in that: The coke coal press (11) and high coal press (12) and shaft furnace (15) are sequentially provided with original five pressurization station mixed gas main pipe pressure sampling point P0 (1), mixed gas main pipe pressure sampling point P1 (2), mixed gas main pipe pressure sampling point P2 (3) and mixed gas main pipe pressure sampling point P3 (4), mixed gas main pipe pressure sampling point P1 (2) is connected to shaft furnace 1#PLC control station (5), mixed gas main pipe pressure sampling point P2 (3) is connected to shaft furnace 3#PLC control station (6), and mixed gas main pipe pressure sampling point P3 (4) is connected to shaft furnace 5#PLC control station (7). ​ 2. The pressure multi-point sampling control system for the shaft furnace gas supply piping network according to claim 1, further comprising an application of the pressure multi-point sampling control system for the shaft furnace gas supply piping network, characterized by, The method comprises the following steps: Step 1, first, three sampling points of mixed gas main pipe pressure sampling point P1 (2), mixed gas main pipe pressure sampling point P2 (3) and mixed gas main pipe pressure sampling point P3 (4) are sequentially arranged at the mixed gas main pipe close to the multiple shaft furnaces (15) in the production area of the two selected shaft furnaces, and the three pressure sampling points of mixed gas main pipe pressure sampling point P1 (2), mixed gas main pipe pressure sampling point P2 (3) and mixed gas main pipe pressure sampling point P3 (4) are measured and signal transmitted by using a pressure gauge and a data line; Step 2, mixed gas main pipe pressure sampling point P1 (2) is sent to shaft furnace 1#PLC control station (5), mixed gas main pipe pressure sampling point P2 (3) is sent to shaft furnace 3#PLC control station (6), and mixed gas main pipe pressure sampling point P3 (4) is sent to shaft furnace 5#PLC control station (7), and the shaft furnace 1#PLC control station (5), shaft furnace 3#PLC control station (6) and shaft furnace 5#PLC control station (7) realize interlocking data sharing of the entire shaft furnace PLC control system through MESSAGE instruction; Step 3, the pressure values of the three sampling points of mixed gas main pipe pressure sampling point P1 (2), mixed gas main pipe pressure sampling point P2 (3) and mixed gas main pipe pressure sampling point P3 (4) are compared and judged by taking two values at random, and the data of the “three out of two” interlocking protection forced stop control program (8) of the reduction gas cut-off valve is used as the interlocking control basis of the reduction gas quick cut-off valve of the multiple shaft furnaces (15), and the data of the “three out of two” interlocking protection forced stop control program (9) of the heating gas cut-off valve is used as the interlocking control basis of the heating gas quick cut-off valve of the multiple shaft furnaces (15), when two pressure points are both less than 3kPa, the mixed gas main pipe pressure does not meet the shaft furnace gas supply pressure requirement, at this time, the five pressurization PLC control station (13) controls to close the gas quick cut-off valve.

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