A method for controlling the balanced water quality of a high-speed production line turbid circulating water system

Abstract

The present invention discloses a method for balanced water quality control of a turbid circulating water system of a high-line production line, which relates to the technical field of steel rolling water systems and comprises the following steps: obtaining a high-line production line status signal; controlling the number of turbid circulating water pumps in operation according to the operation mode and demand in the high-line production line status signal; controlling the number of vortex well water pumps in operation and the water volume of the water pumps in the advection pool by adopting a fuzzy control algorithm according to the operation mode in the second step; when in the third step the number of water pumps in operation in the advection pool cannot meet the balance of the water flow in the turbid circulating water pool; adjusting the amount of water entering the turbid circulating water pool by automatic liquid level control, achieving stable constant pressure water supply and pump current balance of three pump groups of the turbid circulating water pool, the vortex well and the advection pool, thereby reducing power consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of steel rolling water systems, and in particular to a method for controlling balanced water quality in a turbid circulating water system of a high-speed production line. Background Art

[0002] Steel rolling is the process of converting steel ingots or continuous-cast billets produced in steel mills into steel products. Steel products produced by this rolling method can be broadly categorized into sections, wire rods, plates and strips, pipes, and special steels based on their cross-sectional shapes. Steel rolling methods are divided into hot rolling and cold rolling based on the rolling temperature; longitudinal rolling and transverse rolling based on the relative motion between the workpiece and the rollers; and general rolling and special rolling based on the resulting product's forming characteristics.

[0003] Turbid circulating water is the water coming out of the blast furnace slag flushing pump room, which is used to flush the slag in the blast furnace, returns to the slag flushing pool along the slag flushing ditch for sedimentation, and then enters the slag flushing pump room suction well for recycling.

[0004] The control process of the turbid circulating water system of the high-speed rolling mill production line is relatively complex, mainly manifested in the following aspects: 1. The original design of the high-speed line is two production lines, and the supporting water system serves the two production lines. When the third production line is added, the balance of the water system changes. The existing system does not achieve automatic control and relies on manual adjustment of the water level on site; 2. The turbid circulating water system includes: vortex well water pool, horizontal flow pool, and cold water pool. It is difficult to control the liquid level balance of the three production lines at the same time, and manual adjustment of the water system also breaks the stability of the water quality of the horizontal flow pool, resulting in deterioration of the turbid circulating water quality; 3. The high-speed line production line and the water system are independent of each other; 4. The high-speed line production line has high requirements for water supply pressure and cannot produce fluctuations.

[0005] The above analysis shows that the existing turbid water circulation system for high-speed steel rolling mill production lines is generally controlled manually. When the production line needs process adjustments, the on-duty personnel manually adjust the water level based on the pool. This has the following problems: manual control cannot dynamically track the production line's water demand, manual real-time monitoring is labor-intensive, and real-time response is slow. It also affects the water quality of the turbid water circulation system. Summary of the Invention

[0006] In order to solve the problems of the existing technology, the present invention provides a method for balanced water quality control of the turbid circulating water system of a high-line production line, which realizes stable constant pressure water supply and pump current balance of the three pump groups of the turbid circulating water pool, vortex well and horizontal flow pool, thereby reducing power consumption.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a method for controlling the balanced water quality of the turbid circulating water system of a high-speed production line, comprising the following steps:

[0008] The first step is to obtain the high-speed production line status signal;

[0009] The second step is to control the number of turbid water pumps in operation according to the operation mode and demand in the high-speed production line status signal;

[0010] The third step is to use the fuzzy control algorithm to control the number of running water pumps in the vortex well and the running water volume of the water pumps in the advection pool according to the operating mode in the second step;

[0011] Step 4: When the number of running water pumps in the horizontal flow tank cannot meet the water flow balance of the turbid ring water tank in step 3, the amount of water entering the turbid ring water tank is adjusted by automatic liquid level control. The present invention collects high-speed production line signals to obtain the production line operation mode status. According to the production line operation mode status, it automatically controls the number of running pumps and set pressure in the pump group, thus realizing the demand water supply function of the steel rolling high-speed production line.

[0012] As a further improvement of the above technical solution, in the third step, the fuzzy control algorithm adopts the PID algorithm, which controls the speed of the turbid water pump according to the deviation between the actual feedback pressure of the turbid water pump and the set pressure of the turbid water pump; by improving the control algorithm of the pump group, the stable constant pressure water supply and pump current balance of the three pump groups of the turbid water pool, vortex well and flat flow pool are achieved, thereby reducing power consumption.

[0013] As a further improvement of the above technical solution, when controlling the speed of the turbid loop water pump, the deviation between the current PID output and the previous PID output is less than the limit value, and the limit value = (maximum motor frequency ÷ variable frequency acceleration and deceleration time) × (PID execution period ÷ variable frequency acceleration and deceleration time).

[0014] As a further improvement of the above technical solution, according to the fuzzy control algorithm, the interval time of liquid level change is used instead of the liquid level change rate to control the running number of pumps and regulating valves in the vortex well water pool and the advection pool.

[0015] As a further improvement of the above technical solution, the output time interval of the fuzzy control algorithm changes dynamically, and the dynamic change value is adjusted according to the speed of the liquid level change rate.

[0016] As a further improvement to the above technical solution, the pump group selection rules for different production line operation modes are as follows:

[0017] The pump number of the newly added or closed pump is obtained as the current control pump, and the opening of the pump outlet valve is adjusted; the output value of the fuzzy control algorithm is used to adjust the opening value of the return valve.

[0018] As a further improvement of the above technical solution, when the return valve opening is adjusted to the limit, the pump outlet valve opening is adjusted and the number of pump operations is increased or decreased. The output value of the fuzzy control algorithm is multiplied by the proportional coefficient to obtain the pump outlet valve opening, wherein the proportional coefficient of the return valve opening adjustment and the pump outlet valve opening adjustment = return valve diameter 2 ÷ pump outlet valve diameter 2.

[0019] As a further improvement of the above technical solution, when the output value of the fuzzy control algorithm is greater than zero, the backwater valve opening value = the last controlled opening of the backwater valve + the output value of the fuzzy control algorithm.

[0020] As a further improvement of the above technical solution, when the return valve opening value exceeds the maximum value, the pump stop outlet valve opening is reduced according to the pump number of the current pump stop; the pump stop outlet valve opening = the last controlled opening of the pump stop outlet valve - the output value of the fuzzy control algorithm × the proportional coefficient.

[0021] As a further improvement of the above technical solution, in the fourth step, the automatic liquid level control includes a pressure relief pipe connected to the water pump on the horizontal flow pool, and an electrically controlled regulating valve is provided on the pressure relief pipe; the outlet valve of the horizontal flow pool water pump of the present invention adjusts the valve opening according to the liquid level control of the turbid ring water pool, which can save water pump current.

[0022] From the above technical solutions, it can be seen that the beneficial effects of the present invention are as follows: the present invention acquires the production line operation mode status by collecting the high-speed production line signal, and automatically controls the number of pumps in operation and the set pressure in the pump group according to the production line operation mode status, thereby realizing the demand water supply function of the steel rolling high-speed production line;

[0023] The present invention improves the control algorithm of the pump group to achieve stable constant pressure water supply and pump current balance of the three pump groups of the turbid water ring pool, vortex well and advection pool, thereby reducing power consumption;

[0024] The present invention realizes liquid level balance control of the three water pools of the turbid water ring pool, the vortex well and the advection pool, realizes automatic control of the turbid water ring system, ensures that the turbid water ring system automatically and dynamically tracks the water demand of the production line, eliminates the shortcomings of high labor intensity and slow real-time response of manual operation, reduces equipment accidents caused by manual failure to observe and adjust the vortex well liquid level in time, and avoids overflow of the turbid water ring pool and energy waste;

[0025] The outlet valve of the advection tank water pump of the present invention controls the valve opening according to the liquid level of the turbid ring water tank, which can save the water pump current. Through actual operation, the motor of a single water pump is reduced by 60A, P = 1.732 * UIcosψ = ​​1.732 * 380 * 60 * 0.85 = 33.6 kw / h, and the annual electricity cost saving of three water pumps = 33.6 * 24 * 365 * 0.52 * 3 = 450,000 yuan / year;

[0026] The present invention achieves the stability of the water quality of the turbid circulating water system. The normal water flow direction of the advection tank is from north to south, and the pressure relief return water of the advection tank water pump flows from south to north. The unstable water volume disrupts the treatment of the water quality of the advection tank, causing the turbidity of the turbid circulating water system to increase by 20NTU, affecting the quality of the wire rod. After the implementation of this method, the turbidity is reduced to 40NTU, meeting production needs; reducing the water used for sewage replacement, reducing the sewage discharge volume by 150m3 per day, and saving annual costs = 150*365*2.5 = 137,000 yuan / year. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for the description. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a flow chart of the method for controlling the balanced water quality of the turbid circulating water system of the high-line production line. DETAILED DESCRIPTION

[0029] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this patent.

[0030] refer to Figure 1 As shown, the present invention provides a balanced water quality control system for a high-line production line turbid water system, comprising a vortex well, a horizontal flow tank, a turbid water tank, a turbid water pump and a high-line production line connected in sequence;

[0031] A method for balancing a water quality control system for a high-speed production line turbid circulating water system comprises the following steps:

[0032] First, obtain the high-speed production line status signal. The production line status includes three operating modes: 1 line, 2 lines, and 3 lines;

[0033] Second, the number of turbid water supply pumps in operation is controlled based on the operating mode and demand in the high-speed production line status signal. There are four turbid water supply pumps, and the four pumps are divided into two flow modes;

[0034] Third, based on the operating mode in the second step, a fuzzy control algorithm is used to control the number of running water pumps in the vortex well and the water volume of the water pumps in the advection pool. There are a total of 8 water pumps in the vortex well.

[0035] Fourth, due to the volume of the turbidity ring water tank, controlling the number of running water pumps in the advection pool in the third step cannot meet the balance of the water flow in the turbidity ring water tank. A pressure relief pipe is added to the water pump on the advection pool, and an electric control valve is added to the pipe to adjust the amount of water entering the turbidity ring water tank through automatic liquid level control; controlling the amount of water entering the advection pool can also regulate the balance of the water system in the advection pool, reduce the disturbance to the water flow in the advection pool, adjust the changes in water quality in the advection pool, and stabilize the water quality treatment in the advection pool.

[0036] The fuzzy control algorithm adopts the PID algorithm to control the speed of the turbid loop water pump according to the deviation between the actual feedback pressure of the turbid loop water pump and the set pressure of the turbid loop water pump. The deviation between the current PID output and the previous PID output is less than the limit value, and the limit value = (maximum motor frequency ÷ variable frequency acceleration and deceleration time) × (PID execution period ÷ variable frequency acceleration and deceleration time).

[0037] A fuzzy control algorithm uses the interval between liquid level changes, rather than the rate of change, to control the number of pumps and regulating valves in both the vortex well and the advection pool. The fuzzy control algorithm's output interval changes dynamically, and the dynamic change value is adjusted based on the rate of change of the liquid level.

[0038] Combining the above algorithms, the pump group selection rules for different production line operation modes include:

[0039]

[0040] Based on the pump group selection rules, the pump number of the newly added or deactivated pump is obtained as the current controlled pump, and the pump outlet valve opening is adjusted. The output value of the fuzzy control algorithm is used to adjust the return valve opening. When the return valve opening reaches its limit, the pump outlet valve opening is adjusted and the number of operating pumps is increased or decreased. The output value of the fuzzy control algorithm is multiplied by a proportional coefficient to obtain the pump outlet valve opening. The proportional coefficient between the return valve opening adjustment and the pump outlet valve opening adjustment is calculated as: return valve diameter 2 ÷ pump outlet valve diameter 2. When the output value of the fuzzy control algorithm is greater than zero, the return valve opening is calculated as the last controlled return valve opening + the output value of the fuzzy control algorithm. When the return valve opening exceeds the maximum value, the pump outlet valve opening is reduced based on the number of the currently deactivated pump. The deactivated pump outlet valve opening is calculated as: last controlled pump outlet valve opening - output value of the fuzzy control algorithm × proportional coefficient.

[0041] From the above examples, it can be seen that the present invention has the advantages of automatic control, liquid level regulation, system balance, stable water quality, and inherently safe operation of the equipment:

[0042] Specifically, the present invention acquires the production line operation mode status by collecting high-speed production line signals, and automatically controls the number of pumps in operation and the set pressure in the pump group according to the production line operation mode status, thereby realizing the demand water supply function of the steel rolling high-speed production line;

[0043] The present invention improves the control algorithm of the pump group to achieve stable constant pressure water supply and pump current balance of the three pump groups of the turbid water ring pool, vortex well and advection pool, thereby reducing power consumption;

[0044] The present invention realizes liquid level balance control of the three water pools of the turbid water ring pool, the vortex well and the advection pool, realizes automatic control of the turbid water ring system, ensures that the turbid water ring system automatically and dynamically tracks the water demand of the production line, eliminates the shortcomings of high labor intensity and slow real-time response of manual operation, reduces equipment accidents caused by manual failure to observe and adjust the vortex well liquid level in time, and avoids overflow of the turbid water ring pool and energy waste;

[0045] The outlet valve of the advection tank water pump of the present invention controls the valve opening according to the liquid level of the turbid ring water tank, which can save the water pump current. Through actual operation, the motor of a single water pump is reduced by 60A, P = 1.732 * UIcosψ = ​​1.732 * 380 * 60 * 0.85 = 33.6 kw / h, and the annual electricity cost saving of three water pumps = 33.6 * 24 * 365 * 0.52 * 3 = 450,000 yuan / year;

[0046] The present invention achieves the stability of the water quality of the turbid circulating water system. The normal water flow direction of the advection tank is from north to south, and the pressure relief return water of the advection tank water pump flows from south to north. The unstable water volume disrupts the treatment of the water quality of the advection tank, causing the turbidity of the turbid circulating water system to increase by 20 NTU, affecting the quality of the wire rod. After the implementation of this method, the turbidity is reduced to 40 NTU, meeting production needs; the water used for sewage replacement is reduced, and the sewage discharge volume is reduced by 150m3 per day, with an annual cost saving of 150*365*2.5=137,000 yuan / year.

[0047] The terms "upper," "lower," "outer," "inner," and the like, if used in the present description and claims, and in the accompanying drawings, are used to distinguish relative positions and are not necessarily qualitative. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be implemented in sequences other than those illustrated or described herein. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions.

[0048] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling the balanced water quality of a high-speed production line turbid circulating water system, characterized in that: The following steps are included: The first step is to obtain the high-speed production line status signal; The second step is to control the number of turbid water pumps in operation according to the operation mode and demand in the high-speed production line status signal; The third step is to use the fuzzy control algorithm to control the number of running water pumps in the vortex well and the running water volume of the water pumps in the advection pool according to the operating mode in the second step; Step 4: When the number of water pumps in the horizontal flow tank cannot meet the balance of water flow in the turbidity ring water tank in step 3, the amount of water entering the turbidity ring water tank is adjusted by automatic liquid level control; In the third step, the fuzzy control algorithm adopts the PID algorithm, which controls the speed of the turbid water pump according to the deviation between the actual feedback pressure of the turbid water pump and the set pressure of the turbid water pump; When controlling the speed of the turbid water pump, the deviation between the current PID output and the previous PID output is less than the limit value. The limit value = (maximum motor frequency ÷ variable frequency acceleration and deceleration time) × (PID execution period ÷ variable frequency acceleration and deceleration time); In the fourth step, the liquid level automatic control includes a pressure relief pipe connected to the water pump on the advection tank, and an electronically controlled regulating valve is provided on the pressure relief pipe.

2. The method for controlling the balanced water quality of the turbid circulating water system of a high-speed production line according to claim 1 is characterized in that: According to the fuzzy control algorithm, the interval time of liquid level change is used instead of the liquid level change rate to control the running number of pumps and regulating valves in the vortex well pool and the advection pool.

3. The method for controlling the balanced water quality of the turbid circulating water system of a high-speed production line according to claim 2 is characterized in that: The output time interval of the fuzzy control algorithm changes dynamically, and the dynamic change value is adjusted according to the speed of the liquid level change rate.

4. The method for controlling the balanced water quality of a high-speed production line turbid circulating water system according to claim 3 is characterized in that: Pump group selection rules for different production line operation modes: The pump number of the newly added or closed pump is obtained as the current control pump, and the opening of the pump outlet valve is adjusted; the output value of the fuzzy control algorithm is used to adjust the opening value of the return valve.

5. The method for controlling the balanced water quality of the turbid circulating water system of a high-speed production line according to claim 4 is characterized in that: When the return valve opening is adjusted to the limit, the pump outlet valve opening is adjusted and the number of pump operations is increased or decreased. The output value of the fuzzy control algorithm is multiplied by the proportional coefficient to obtain the pump outlet valve opening. Among them, the proportional coefficient of the return valve opening adjustment and the pump outlet valve opening adjustment = return valve diameter² ÷ pump outlet valve diameter².

6. The method for controlling the balanced water quality of a high-speed production line turbid circulating water system according to claim 5, characterized in that: When the output value of the fuzzy control algorithm is greater than zero, the backwater valve opening value = the last controlled opening of the backwater valve + the output value of the fuzzy control algorithm.

7. The method for controlling the balanced water quality of a high-speed production line turbid circulating water system according to claim 5, characterized in that: When the return valve opening value exceeds the maximum value, the pump outlet valve opening is reduced according to the pump number of the current pump stop; the pump outlet valve opening = the last controlled opening of the pump outlet valve - the output value of the fuzzy control algorithm × the proportional coefficient.

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