A blast furnace top and a method for stabilizing water supply of a purification booster system

Abstract

The application discloses a method for stably supplying water for a blast furnace top and a purification pressurizing system, and relates to the technical field of blast furnace smelting. The method combines the blast furnace top and the purification pressurizing water system into a unified water supply mother pipe, and real-time acquisition of flow and pressure signals of the mother pipe, vibration acceleration and motor current waveform of a variable frequency pump set is realized. Variable frequency pump set linkage control logic is executed based on the flow and pressure signals; meanwhile, anti-pump choking and cavitation suppression control logic is executed based on the flow, vibration and current waveform. Finally, two-way regulation instructions are logically combined to generate multi-mode adaptive regulation instructions to control the pump set and the valve. The application realizes dynamic balance between intermittent water use and water supply capacity, effectively eliminates pump choking and cavitation, prolongs the service life of the equipment, improves the system stability and significantly reduces reactive power consumption.

Description

Technical Field

[0001] This invention relates to the field of blast furnace smelting technology, and in particular to a method for stable water supply to the blast furnace top and purification and pressurization system. Background Technology

[0002] The original design of the blast furnace top water supply system was usually an independent water supply unit, mainly serving the intermittent water needs of key components of the furnace top equipment. According to the production process requirements, the water consumption at user points exhibits a significant "intermittent" characteristic: the minimum water consumption can reach 0 m³ / h, the water demand is not continuous and stable, and the interval period is not fixed (it may be on the order of minutes to hours).

[0003] The original design generally adopted the conventional water supply mode of "constant pressure fixed frequency pump set + independent pipeline", which was not optimized for intermittent water use characteristics, resulting in the following prominent problems: 1. Pump Stalling and Cavitation Damage: When a user suspends water supply, the water pump continues to run but without actual flow output, causing pressure to accumulate in the pipeline (pump stalling). Simultaneously, a sudden drop in water velocity creates a localized vacuum, leading to liquid vaporization and bubble formation at the pump impeller inlet. The collapse of these bubbles in the high-pressure zone generates high-frequency impact forces, causing metal peeling from the impeller surface and pump casing corrosion (cavitation). In severe cases, excessive pump vibration and abnormal noise directly threaten the equipment's lifespan.

[0004] 2. Decreased water supply stability: Cavitation reduces pump efficiency, and it takes a long time to adjust the pressure when water is restored, which may lead to insufficient cooling of the furnace top equipment and directly affect the smooth operation of the blast furnace.

[0005] 3. Energy waste: When the pump is stuck, the pump set still operates at its rated power, resulting in significant reactive power loss, which does not meet the company's goal of reducing costs and increasing efficiency. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for stable water supply to the blast furnace top and the purification and pressurization system.

[0007] To solve the above technical problems, the technical solution of the present invention is as follows: A method for stabilizing water supply to the top of a blast furnace and a purification and pressurization system includes the following steps: The system acquires real-time flow and pressure signals from the unified water supply header, as well as the vibration acceleration signal of the pump casing and the motor current waveform of the variable frequency pump unit connected to the unified water supply header. The unified water supply header is a pipeline connecting the blast furnace top pressurized water system and the purified pressurized water system, and is equipped with water supply pipeline valves. Based on real-time flow and pressure signals, the variable frequency pump group linkage control logic is executed to determine the adjustment command of the first pump group. Based on real-time flow signals, pump casing vibration acceleration signals, and motor current waveforms, anti-pump blockage and cavitation suppression control logic is executed to determine the adjustment command for the second pump group. The adjustment commands of the first pump group and the second pump group are logically combined to generate a multi-mode adaptive adjustment command, and the variable frequency pump group and water supply pipeline valves are controlled according to the multi-mode adaptive adjustment command.

[0008] The beneficial effects of this invention are: (1) This invention merges the original blast furnace top pressurized water system and the purified pressurized water system into a unified water supply system. Based on the merged pipeline network, a PID algorithm combining real-time flow and real-time pressure is used to activate the standby pump in advance when the flow rate surges and smoothly reduce the frequency when the flow rate decreases. This linkage control logic ensures accurate matching between the system output flow rate and the instantaneous water consumption at the user point, avoids pressure interruptions when water is restored, and ensures blast furnace cooling and smooth production.

[0009] (2) By monitoring the flow signal, when the flow rate is zero or below the preset flow threshold, the system actively reduces the frequency to the maintenance frequency and maintains the basic circulation through the minimum flow return branch, thus eliminating the closed overpressure environment that causes "pump stalling" from a physical mechanism. At the same time, by extracting the high-frequency vibration component of the pump casing through frequency domain analysis and monitoring the motor current fluctuation rate, the system can accurately identify the occurrence of cavitation characteristics and automatically adjust the frequency according to the preset step size or open the return valve to release air and pressure, avoiding metal peeling and corrosion on the impeller surface caused by bubble collapse, greatly extending the service life of the water pump and reducing maintenance and spare parts costs.

[0010] (3) The multi-mode adaptive adjustment mechanism constructed in this invention includes a low-power standby mode. In situations where there is no water usage for a long time, such as at night or during maintenance, the backup pump is automatically shut down, and only the single pump is kept to maintain internal circulation at the lowest permissible frequency, thus completely eliminating the "dead running" power loss of traditional fixed-frequency pumps under zero-flow conditions. In addition, the dual effects of system merging and cavitation protection significantly reduce the replacement frequency of the pump impeller. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of the pipeline network and frequency conversion control system provided in an embodiment of the present invention; Figure 2This is a schematic flowchart illustrating a method for stable water supply to the blast furnace top and purification pressurization system provided in an embodiment of the present invention. Detailed Implementation

[0013] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0014] This embodiment provides a method for stable water supply to the blast furnace top and purification pressurization system. This method is based on a combined and modified pipeline network and frequency conversion control system. See also... Figure 1 At the physical level, the original blast furnace top pressurized water system and the purified pressurized water system were first merged into a unified water supply main pipe by adding connecting pipelines and valve groups. Pressure transmitters and flow meters were installed on the merged water supply main pipe, each pump of the variable frequency pump set was equipped with an independent frequency converter, and vibration sensors were added to the pump body. All relevant signals were connected to the PLC controller for unified scheduling.

[0015] See Figure 2 Based on the above system, the method in this embodiment specifically includes the following steps: Step S10: Obtain the real-time flow and pressure signals of the unified water supply main pipe, as well as the pump casing vibration acceleration signal and motor current waveform of the variable frequency pump set connected to the unified water supply main pipe.

[0016] Specifically, the PLC controller acquires real-time flow and pressure signals from the unified water supply main pipe. Simultaneously, it collects the pump casing vibration acceleration signal and motor current waveform of the variable frequency pump unit connected to this main pipe. This step provides comprehensive data support for subsequent intelligent scheduling and equipment protection.

[0017] Step S20: Based on the real-time flow signal and the real-time pressure signal, execute the variable frequency pump group linkage control logic to determine the first pump group adjustment command.

[0018] Specifically, this step primarily addresses flow fluctuations during normal water usage. A target pressure is preset within the PLC. During operation, the real-time pressure signal is compared with the target pressure, and the changing trend of the real-time flow signal is also incorporated. A PID algorithm is then used to calculate the base frequency adjustment.

[0019] 1) Flow boosting mode: When the flow meter shows an increase in water consumption, and the frequency of the currently running pump has automatically increased to the preset frequency limit, but the main pipe pressure is still lower than the target pressure, the PLC determines that the single pump capacity is insufficient, and then automatically generates an instruction to start a standby pump, and reallocates the operating frequencies of the two pumps according to the PID algorithm to achieve smooth grid connection.

[0020] 2) Reduced flow condition: When the flow meter shows a decrease in water consumption, the PLC prioritizes controlling the reduction of the frequency of one of the operating pumps; if the pump frequency has been reduced to the preset lower limit and the system pressure is still higher than the set demand pressure, the PLC issues a command to smoothly shut down one pump and operate with a single pump.

[0021] This linkage control ensures that the system output basically matches the user's instantaneous water consumption.

[0022] Step S30: Based on the real-time flow signal, pump casing vibration acceleration signal and motor current waveform, execute the anti-pump blockage and cavitation suppression control logic to determine the adjustment command for the second pump group.

[0023] Specifically, this step targets the most extreme condition of "complete cessation or minimal water flow" in the intermittent characteristics of the blast furnace top, aiming to provide self-protection for the equipment.

[0024] 1) Anti-stagnant pump logic: When the flow meter detects that the real-time flow rate is continuously lower than the preset "minimum safe flow threshold", and this low flow state is maintained for a longer than the preset delay setting, the PLC automatically takes over control, bypassing the conventional PID controller, and forcibly and rapidly reduces the frequency of the currently running variable frequency pump to the "preset maintenance frequency". At this frequency, the pump outlet water flows back to the water tank through the minimum flow return branch added to the system, maintaining the basic circulation flow rate, fundamentally avoiding pipe network stagnation and overpressure caused by complete valve closure.

[0025] 2) Anti-cavitation logic: The system synchronously performs frequency domain analysis on the collected pump casing vibration acceleration signal. If the high-frequency vibration component characteristic of bubble rupture is extracted, or if the motor current waveform shows irregular abnormal fluctuations caused by cavitation exceeding the current threshold, the system determines that cavitation has occurred. At this time, the PLC generates a protection command, which slightly increases or decreases the frequency of the variable frequency pump according to a preset adjustment step, or opens the reflux valve for a preset duration to change the pressure field distribution in the pump cavity, forcing the bubbles to be discharged or suppressing their generation, until the high-frequency vibration and abnormal current characteristics disappear.

[0026] Step S40: Logically combine the first pump group adjustment command and the second pump group adjustment command to generate a multi-mode adaptive adjustment command, and control the variable frequency pump group and water supply pipeline valves according to the multi-mode adaptive adjustment command.

[0027] Specifically, to avoid command conflicts between conventional linkage control and abnormal protection control, the system performs adaptive integration and allocation by acquiring the rate of change of user water usage behavior.

[0028] When the system meets preset no-water conditions during production breaks (e.g., the real-time flow signal remains zero for more than the sleep duration threshold), the system enters a "preset standby mode." In this mode, the PLC automatically shuts down all standby pumps, keeping only one variable frequency pump running at the minimum allowed operating frequency, while keeping the minimum flow return valve open. At this time, only a very small amount of water circulates within the pump body. Once the real-time flow signal is detected to be greater than zero, indicating that user water demand has resumed, the system immediately issues a frequency ramp command based on a preset ramp rate to quickly restore the pipeline pressure.

[0029] In a practical application during the overhaul window of blast furnace No. 3 at a steel plant, the method described in this invention was used to optimize and upgrade the water supply system. Before the upgrade, the total power of the motors in the two independent water supply systems was 215 kW; after the upgrade, by merging the pipeline network and using frequency conversion control, the power of the motors in one water supply system was reduced to 200 kW.

[0030] This stable water supply technology completely eliminated pump stalling and cavitation problems caused by intermittent water use by users at the furnace top, significantly improving the stability of the two water supply systems.

[0031] In terms of economic benefits, the annual electricity cost savings are approximately: (215kW - 200kW) * 24 hours * 30 days * 12 months * 0.65 yuan / kWh / 10,000 = 73,700 yuan. Simultaneously, by eliminating pump stalling and cavitation damage, annual savings of approximately 60,000 yuan can be achieved in maintenance and spare parts costs for pump impellers, seals, etc.

[0032] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A method for stabilizing the water supply to a blast furnace top and a clean-up booster system, characterized in that: Includes the following steps: The system acquires real-time flow and pressure signals from the unified water supply main pipe, as well as the pump casing vibration acceleration signal and motor current waveform of the variable frequency pump unit connected to the unified water supply main pipe; wherein, the unified water supply main pipe is a pipeline connecting the blast furnace top pressurized water system and the purified pressurized water system, and the unified water supply main pipe is equipped with water supply pipeline valves. Based on the real-time flow signal and the real-time pressure signal, the variable frequency pump group linkage control logic is executed to determine the first pump group adjustment command; Based on the real-time flow signal, the pump casing vibration acceleration signal, and the motor current waveform, the anti-pump blockage and cavitation suppression control logic is executed to determine the adjustment command for the second pump group. The first pump group adjustment command and the second pump group adjustment command are logically combined to generate a multi-mode adaptive adjustment command, and the variable frequency pump group and the water supply pipeline valve are controlled according to the multi-mode adaptive adjustment command.

2. The method of claim 1, wherein the blast furnace top and the method of stabilizing the water supply of the purification supercharging system are characterized by: Based on the real-time flow signal and the real-time pressure signal, the variable frequency pump group linkage control logic is executed to determine the first pump group adjustment command, which includes: The real-time pressure signal is compared with the preset target pressure, and the basic frequency adjustment is calculated based on the PID algorithm, taking into account the changing trend of the real-time flow signal. When the real-time flow signal is on an upward trend and the frequency of the currently operating pump has risen to the preset frequency limit, but the real-time pressure signal is still lower than the target pressure, an instruction to start the standby pump and reallocate the operating frequency is generated as the first pump group adjustment instruction. When the real-time flow signal is in a downward trend, an instruction is generated to prioritize reducing the operating frequency of a single pump; if the frequency drops to a preset lower limit and the real-time pressure signal is still higher than the preset required pressure, an instruction to shut down one pump is generated as the first pump group adjustment instruction.

3. The method for stable water supply to the blast furnace top and purification pressurization system according to claim 1, characterized in that: Based on the real-time flow signal, the pump casing vibration acceleration signal, and the motor current waveform, the anti-pump blockage and cavitation suppression control logic is executed to determine the second pump group adjustment command, which includes: When the system is determined to be in a state of zero flow or below the preset flow threshold based on the real-time flow signal, the control logic of reducing the frequency to the preset maintenance frequency is executed to generate an anti-stagnation pump adjustment command. The pump housing vibration acceleration signal and the motor current waveform are analyzed in real time. When cavitation characteristics are identified, cavitation suppression control logic is executed to generate cavitation protection adjustment commands. The anti-stuck pump adjustment command and the cavitation protection adjustment command are combined to form the second pump group adjustment command.

4. The blast furnace top and method of stabilizing water supply to the clean booster system according to claim 3, characterized in that: When the system is determined to be in a state of zero flow or below a preset flow threshold based on the real-time flow signal, the control logic of reducing the frequency to a preset maintenance frequency is executed, and the anti-stagnation pump adjustment command is generated, including: When the real-time flow signal is continuously lower than the preset minimum safe flow threshold and the duration exceeds the preset delay setting value, it is determined that the working condition of being lower than the preset flow threshold is met. A command is generated to reduce the frequency of the currently running variable frequency pump to the preset maintenance frequency, so that the pump outlet maintains the basic circulation flow rate; wherein, the basic circulation flow rate is achieved through an additional minimum flow return branch.

5. The method of claim 3, wherein the blast furnace roof and the method of stabilizing the water supply of the clean-up plenum system are characterized by: Real-time analyzing the pump shell vibration acceleration signal and the motor current waveform, when the cavitation feature is identified, executing cavitation suppression control logic, generating cavitation protection adjustment instructions include: Frequency domain analysis is performed on the pump shell vibration acceleration signal to extract high-frequency vibration components, while monitoring the fluctuation rate of the motor current waveform; When the high-frequency vibration component exceeds the preset vibration threshold or the fluctuation rate exceeds the preset current threshold, it is determined that the cavitation feature is identified; Generate instructions to change the frequency of the variable frequency pump according to the preset adjustment step or open the backflow valve for a preset opening time until the high-frequency vibration component and the fluctuation rate return to the preset normal range.

6. The method of claim 1, wherein the blast furnace roof and the method of stabilizing the water supply of the clean-up plenum system are characterized by: Logical combination of the first pump group adjustment instruction and the second pump group adjustment instruction to generate multi-mode adaptive adjustment instructions include: According to the change rate of the real-time flow signal, determine the change rate of the user's water use behavior; Based on the change rate, automatically switch between a plurality of pressure adjustment modes, the plurality of pressure adjustment modes at least including a conventional PID adjustment mode, a feedforward compensation mode and a preset power consumption standby mode; When the preset non-use water condition is met, trigger the preset power consumption standby mode to generate corresponding multi-mode adaptive adjustment instructions.

7. The blast furnace top and method of stabilizing water supply to the clean booster system according to claim 6, characterized in that: Triggering the low-power standby mode to generate corresponding multi-mode adaptive adjustment instructions includes: When the time when the real-time flow signal is continuously detected to be zero exceeds the preset sleep duration threshold, it is determined that the non-use water condition is met, and instructions to turn off all standby pumps are generated; Generate instructions to keep only one variable frequency pump running at the lowest allowed frequency; Generate instructions to open the minimum flow backflow valve to maintain the basic circulation flow inside the pump body, and generate frequency increasing instructions based on the preset frequency increasing rate when the real-time flow signal is greater than zero.

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