阅读说明：本技术 一种废钢预热控制系统及控制方法 (Scrap steel preheating control system and control method ) 是由 弭飞飞 陈高强 魏国 刚占库 涂赣峰 于 2020-06-15 设计创作，主要内容包括：本发明属于固废利用技术领域,具体涉及一种废钢预热控制系统及控制方法,系统包括上位机、控制器、信号采集组件和动作控制组件,信号采集组件包括温度采集单元、压力采集单元、流量采集单元和火焰检测单元,动作控制组件包括管路调节阀门、管路气动阀门、行程开关、动作控制电机和打火装置,上位机和控制器之间通过交换机连接,动作控制电机通过变频器或软启动器也连接在交换机上,信号采集组件和管路调节阀门、管路气动阀门、行程开关、打火装置均分别与控制器连接,信号采集组件用于采集废钢预热装置各部位的温度、压力和流量,动作控制组件用于对废钢预热装置各部位进行控制调节,本发明自动化程度高,运行成本低。(The invention belongs to the technical field of solid waste utilization, and particularly relates to a scrap steel preheating control system and a control method, wherein the system comprises an upper computer, a controller, a signal acquisition assembly and an action control assembly, the signal acquisition assembly comprises a temperature acquisition unit, a pressure acquisition unit, a flow acquisition unit and a flame detection unit, the action control assembly comprises a pipeline adjusting valve, a pipeline pneumatic valve, a travel switch, an action control motor and an ignition device, the upper computer and the controller are connected through a switch, the action control motor is also connected on the switch through a frequency converter or a soft starter, the signal acquisition assembly, the pipeline adjusting valve, the pipeline pneumatic valve, the travel switch and the ignition device are respectively connected with the controller, the signal acquisition assembly is used for acquiring the temperature, the pressure and the flow of each part of the scrap steel preheating device, and the action control assembly is used for controlling and adjusting each part of the scrap steel preheating device, the invention has high automation degree and low operation cost.)

1. A scrap steel preheating control system is used for controlling a scrap steel preheating device and is characterized by comprising an upper computer, a controller, a signal acquisition assembly and an action control assembly, wherein the signal acquisition assembly comprises a temperature acquisition unit, a pressure acquisition unit, a flow acquisition unit and a flame detection unit, the action control assembly comprises a pipeline adjusting valve and a pipeline pneumatic valve, travel switch, action control motor and ignition device, connect through the switch between host computer and the controller, the action control motor passes through converter or soft starter and also connects on the switch, signal acquisition subassembly and pipeline adjusting valve, pipeline pneumatic valve, travel switch, ignition device are equallyd divide and are do not connected with the controller, the signal acquisition subassembly is used for gathering the temperature, pressure and the flow of each position of scrap steel preheating device, the action control subassembly is used for carrying out the control regulation to each position of scrap steel preheating device.

2. The scrap preheating control system according to claim 1, wherein the scrap preheating device includes a feeding unit, a preheating unit, and a discharging unit, the motion control motor includes a ladle cover lifting motor and an oxygen burner lifting motor, the feeding unit is used for transporting scrap to the preheater, the preheating unit includes a preheater, a ladle cover, and an oxygen burner, the ladle cover is controlled by the ladle cover lifting motor to move up and down, the oxygen burner is controlled by the oxygen burner lifting motor to move up and down, a burner port of the oxygen burner is vertically downward, the ignition device is connected to a burner port of the oxygen burner, the flame detection unit is disposed beside the ladle cover and is used for detecting flame, the preheating unit further includes a cooling water line, a gas line, an oxygen line, a propane line, a nitrogen line, and a flue gas line, the cooling water line, the gas line, the oxygen line, the propane line, and the nitrogen line are all connected to the oxygen burner, the flue gas pipeline is connected with the smoke exhaust main pipe, the ignition device ignites propane, propane fire ignites coal gas, nitrogen is used for purging the coal gas pipeline, the safety of equipment is guaranteed, coal gas and oxygen are mixed and combusted, flame is sprayed out from a combustion port, scrap steel is directly preheated, cooling water is used for cooling an oxygen combustion gun, and a preheater conveys the scrap steel to the discharging unit after preheating is completed.

3. The scrap preheating control system according to claim 2, wherein the temperature collecting units are respectively provided on the inlet of the cooling water line, the outlet of the cooling water line, the gas line, the oxygen line and the inner wall of the ladle cover, the pressure collecting units are respectively provided on the gas line, the oxygen line, the nitrogen line, the propane line and the cooling water line, and the flow collecting units are respectively provided on the gas line, the oxygen line, the nitrogen line and the cooling water line;

the pipeline adjusting valves are respectively arranged on a gas pipeline and an oxygen pipeline, and the pipeline pneumatic valves are respectively arranged on the gas pipeline, the oxygen pipeline, the propane pipeline, the nitrogen pipeline, the cooling water pipeline and the flue gas pipeline; the travel switches are respectively arranged at the upper limit position and the lower limit position of the oxygen combustion gun, the upper limit position and the lower limit position of the ladle cover and the in-place position of the preheater.

4. The scrap preheating control system according to claim 1, wherein the upper computer includes a master upper computer and a plurality of slave upper computers, the master upper computer and the slave upper computers are respectively connected to the exchanger, the master upper computer is used for performing on-site monitoring and modification, the slave upper computers are used for process value collection, monitoring and report printing, and the exchanger is an industrial network using TCP/IP protocol or Profibus.

5. The scrap steel preheating control system according to claim 4, wherein Siemens WinCC configuration software is installed in the master upper computer and the slave upper computers to serve as graphical monitoring control terminals, and the master upper computer and the slave upper computers are respectively assigned with different authorities.

6. The scrap preheating control system according to claim 1, wherein the controller is a Simatic S7-1500 or S7-300PLC, and a TCP/IP and Profinet interface of the PLC is adopted.

7. The scrap steel preheating control system according to claim 1, wherein the temperature collection unit is a temperature transmitter, the pressure collection unit is a pressure transmitter, and the flow collection unit is a flow meter.

8. A control method for preheating scrap using the scrap preheating control system according to claim 3, comprising the steps of:

1) the travel switch reads the positions of the on-site ladle cover and the oxygen combustion gun, the temperature acquisition unit reads the medium temperatures of an inlet of the cooling water pipeline, an outlet of the cooling water pipeline, the gas pipeline, the oxygen pipeline and the preheater, and the pressure acquisition unit reads the medium pressures in the gas pipeline, the oxygen pipeline, the nitrogen pipeline, the propane pipeline and the cooling water pipeline;

2) the collected data information is transmitted to the controller, the controller transmits the data to the upper computer, and meanwhile, whether all data of the scrap steel preheating device are normal or not is judged;

3) if the alarm signal or the prompt message is not given normally, the site scrap steel preheating device is checked or overhauled, and then the step 1) and the step 2) are repeated;

4) if normal, each part of host computer control start steel scrap preheating device, the material loading unit transports the steel scrap to the pre-heater in, and oxygen fires rifle elevator motor control oxygen and fires the rifle and descend to the pre-heater in, and ladle cover elevator motor control ladle cover descends to the pre-heater upper end, ignition device strikes sparks, whether flame detecting element detects successfully striking sparks, and flame carries out the direct heating to the steel scrap, and each signal acquisition subassembly gathers the signal of preheating the in-process in real time, preheats the completion back, and ladle cover elevator motor control ladle cover rises, and oxygen fires rifle elevator motor control oxygen and rises, and the pre-heater transports the steel scrap that preheats to unloading in the unit, accomplishes the steel scrap and preheats.

Technical Field

The invention belongs to the technical field of solid waste utilization, and particularly relates to a scrap steel preheating control system and a scrap steel preheating control method.

Background

The production cost of the electric arc furnace for steelmaking is adopted at present, the electric energy consumption is the largest, and particularly, the situation of electric energy shortage in China greatly increases the steelmaking cost of the electric arc furnace. In the smelting process of the electric arc furnace, the power supply time of the melting stage of furnace materials is longest, the electric energy consumption is the largest, and the melting period accounts for more than half of one smelting period; the main reason is that the temperature of the added cold scrap steel is too low, and the purpose of melting furnace charge by electrifying needs to be achieved, the electric energy input has to be increased, so that the smelting period is long, the electrode consumption is high, and the smelting power consumption is high.

The adoption of the scrap steel preheating technology has the advantages of effectively shortening the smelting period, reducing the smelting consumption, low operating cost, convenient maintenance and management and the like; so far, the prior art mainly utilizes high-temperature flue gas of an electric furnace to preheat scrap steel; the method for preheating the scrap steel by utilizing the high-temperature flue gas of the electric furnace mainly comprises two methods: a direct preheating mode and an indirect preheating mode; the direct preheating mode is characterized in that the flue gas extracted from the electric furnace is used for preheating the steel scrap, and the indirect preheating mode is that the extracted flue gas is used for heating air firstly, and then the heated air is used for preheating the steel scrap.

The latest process mode for preheating the scrap steel adopts the high-temperature flame generated by mixing and burning oxygen and coal gas in a certain proportion to directly blow the scrap steel, obviously, compared with the original mode of preheating the scrap steel by using flue gas, the mode of preheating the scrap steel by using high temperature and high flow saves the preheating time, improves the preheating efficiency, and is more beneficial to matching with the rhythm of field smelting production. In this way, the combustion gas is a variety of gases such as coal gas and oxygen, which are very easy to explode during preheating on site, and a control system is needed to solve the technical problems.

Disclosure of Invention

In order to solve the technical problems, the invention provides a scrap steel preheating control system and a scrap steel preheating control method, which have the advantages of high automation degree and low operation cost.

The invention is realized in such a way, provides a scrap steel preheating control system, is used for controlling a scrap steel preheating device, and comprises an upper computer, a controller, a signal acquisition assembly and an action control assembly, wherein the signal acquisition assembly comprises a temperature acquisition unit, a pressure acquisition unit, a flow acquisition unit and a flame detection unit, the action control assembly comprises a pipeline adjusting valve and a pipeline pneumatic valve, travel switch, action control motor and ignition device, connect through the switch between host computer and the controller, the action control motor passes through converter or soft starter and also connects on the switch, signal acquisition subassembly and pipeline adjusting valve, pipeline pneumatic valve, travel switch, ignition device are equallyd divide and are do not connected with the controller, the signal acquisition subassembly is used for gathering the temperature, pressure and the flow of each position of scrap steel preheating device, the action control subassembly is used for carrying out the control regulation to each position of scrap steel preheating device.

Preferably, the scrap preheating device comprises a feeding unit, a preheating unit and an unloading unit, the action control motor comprises a ladle cover lifting motor and an oxygen combustion gun lifting motor, the feeding unit is used for conveying scrap to the preheater, the preheating unit comprises a preheater, a ladle cover and an oxygen combustion gun, the ladle cover is controlled to move up and down through the ladle cover lifting motor, the oxygen combustion gun is controlled to move up and down through the oxygen combustion gun lifting motor, a combustion port of the oxygen combustion gun is vertically downward, the ignition device is connected with the combustion port of the oxygen combustion gun, the flame detection unit is arranged beside the ladle cover and is used for detecting flame, the preheating unit further comprises a cooling water pipeline, a coal gas pipeline, an oxygen pipeline, a propane pipeline, a nitrogen pipeline and a flue gas pipeline, the cooling water pipeline, the coal gas pipeline, the oxygen pipeline, the propane pipeline and the nitrogen pipeline are all connected with the oxygen combustion gun, the flue gas pipeline is connected with a smoke exhaust main pipe, the ignition device ignites propane, propane fire ignites coal gas, nitrogen is used for purging a gas pipeline, the safety of equipment is guaranteed, coal gas and oxygen are mixed and combusted, flame is sprayed out from a combustion port, scrap steel is directly preheated, cooling water is used for cooling an oxygen combustion gun, and a preheater conveys the scrap steel to the unloading unit after preheating is completed.

Preferably, the temperature acquisition units are respectively arranged on the inlet of the cooling water pipeline, the outlet of the cooling water pipeline, the gas pipeline, the oxygen pipeline and the inner wall of the ladle cover, the pressure acquisition units are respectively arranged on the gas pipeline, the oxygen pipeline, the nitrogen pipeline, the propane pipeline and the cooling water pipeline, and the flow acquisition units are respectively arranged on the gas pipeline, the oxygen pipeline, the nitrogen pipeline and the cooling water pipeline;

the pipeline adjusting valves are respectively arranged on a gas pipeline and an oxygen pipeline, and the pipeline pneumatic valves are respectively arranged on the gas pipeline, the oxygen pipeline, the propane pipeline, the nitrogen pipeline, the cooling water pipeline and the flue gas pipeline; the travel switches are respectively arranged at the upper limit position and the lower limit position of the oxygen combustion gun, the upper limit position and the lower limit position of the ladle cover and the in-place position of the preheater.

Preferably, the host computer comprises a master host computer and a plurality of slave host computers, the master host computer and the slave host computers are respectively connected with the exchanger, the master host computer is used for executing field monitoring and modification, the slave host computers are used for process value acquisition, monitoring and report printing, and the exchanger adopts an industrial network of a TCP/IP protocol or Profibus.

Preferably, Siemens WinCC configuration software is installed in the master upper computer and the slave upper computers and used as graphical monitoring control terminals, and the master upper computer and the slave upper computers are respectively assigned with different authorities.

Further preferably, the controller is a Simatic S7-1500 or S7-300PLC, and TCP/IP and Profinet interfaces of the PLC are adopted.

Further preferably, the temperature acquisition unit is a temperature transmitter, the pressure acquisition unit is a pressure transmitter, and the flow acquisition unit is a flowmeter.

The invention also provides a control method for preheating the scrap steel by using the scrap steel preheating control system, which comprises the following steps:

1) the travel switch reads the positions of the on-site ladle cover and the oxygen combustion gun, the temperature acquisition unit reads the medium temperatures of an inlet of the cooling water pipeline, an outlet of the cooling water pipeline, the gas pipeline, the oxygen pipeline and the preheater, and the pressure acquisition unit reads the medium pressures in the gas pipeline, the oxygen pipeline, the nitrogen pipeline, the propane pipeline and the cooling water pipeline;

2) the collected data information is transmitted to the controller, the controller transmits the data to the upper computer, and meanwhile, whether all data of the scrap steel preheating device are normal or not is judged;

3) if the alarm signal or the prompt message is not given normally, the site scrap steel preheating device is checked or overhauled, and then the step 1) and the step 2) are repeated;

4) if normal, each part of host computer control start steel scrap preheating device, the material loading unit transports the steel scrap to the pre-heater in, and oxygen fires rifle elevator motor control oxygen and fires the rifle and descend to the pre-heater in, and ladle cover elevator motor control ladle cover descends to the pre-heater upper end, ignition device strikes sparks, whether flame detecting element detects successfully striking sparks, and flame carries out the direct heating to the steel scrap, and each signal acquisition subassembly gathers the signal of preheating the in-process in real time, preheats the completion back, and ladle cover elevator motor control ladle cover rises, and oxygen fires rifle elevator motor control oxygen and rises, and the pre-heater transports the steel scrap that preheats to unloading in the unit, accomplishes the steel scrap and preheats.

Compared with the prior art, the invention has the advantages that:

the scrap steel preheating control system provided by the invention has the advantages of high automation degree, low operation cost, modular design of the PLC measurement and control terminal, small volume, light weight, safe and reliable work and functions of online self-checking and program power-off protection.

Drawings

FIG. 1 is a block diagram of a scrap preheating control system according to the present invention;

FIG. 2 is a block diagram of a scrap preheating system.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the invention provides a scrap preheating control system for controlling a scrap preheating device, comprising an upper computer, a controller, a signal acquisition assembly and an action control assembly, wherein the signal acquisition assembly comprises a temperature acquisition unit, a pressure acquisition unit, a flow acquisition unit and a flame detection unit, the action control assembly comprises a pipeline adjusting valve and a pipeline pneumatic valve, travel switch, action control motor and ignition device, connect through the switch between host computer and the controller, the action control motor passes through converter or soft starter and also connects on the switch, signal acquisition subassembly and pipeline adjusting valve, pipeline pneumatic valve, travel switch, ignition device are equallyd divide and are do not connected with the controller, the signal acquisition subassembly is used for gathering the temperature, pressure and the flow of each position of scrap steel preheating device, the action control subassembly is used for carrying out the control regulation to each position of scrap steel preheating device.

The system mainly has the following functions:

1. information collection

The function is mainly completed by the controller, the signal acquisition assembly acquires the current state of the equipment and various alarm information through scanning, and the sampling scanning period is less than 10 ms.

2. Coded transmission

And the controller is used for coding various information collected by the controller and transmitting the coded information to an upper computer operating system through a communication network for further processing.

3. Device control

The function is that the upper computer carries out remote coordination control on each device according to the operation condition of scrap steel preheating and transmits the control to the controller through the network; the controller is responsible for executing various operation commands and collecting operation information during the command execution period and returning the operation information to the upper computer. The control mode comprises single object control and mode control, the operation is carried out by adopting three steps of selection, confirmation and execution, and when the operation is forbidden, the system gives prompt information to remind an operator of paying attention.

4. Condition monitoring

And the display of the upper computer displays the state pictures of all control equipment for preheating the scrap steel in a graphical manner. So as to monitor the current state of each control device for scrap preheating in real time.

5. Fault alarm

The system pops up and displays the fault information in a fault alarm window immediately after detecting the fault information, and displays corresponding fault information, fault points and fault time in different color grade modes; and meanwhile, automatically storing the fault information into a fault information database.

6. Document generation

The function is used for summarizing, analyzing and sorting various information in the system and generating various required reports such as operation records and alarm records, and the modes of daily reports, monthly reports, annual reports and the like can be set according to the requirements of field users.

7. Data statistics and analysis

The function is used for recording simulation information measured in the system into an analog quantity historical database, meanwhile, the data information recorded in the database can be counted and analyzed according to the needs of users to generate a real-time trend graph and a historical trend graph, and the real-time trend graph and the historical trend graph can be called, searched and compared at any time.

Referring to fig. 2, the scrap preheating device includes a feeding unit, a preheating unit and a discharging unit, the motion control motor includes a ladle cover lifting motor and an oxygen combustion gun lifting motor, the feeding unit is used for conveying scrap to the preheater, the preheating unit includes a preheater, a ladle cover and an oxygen combustion gun, the ladle cover is controlled by the ladle cover lifting motor to move up and down, the oxygen combustion gun is controlled by the oxygen combustion gun lifting motor to move up and down, a combustion port of the oxygen combustion gun is vertically downward, the ignition device is connected with the combustion port of the oxygen combustion gun, the flame detection unit is arranged beside the ladle cover and is used for detecting flame, the preheating unit further includes a cooling water pipeline, a gas pipeline, an oxygen pipeline, a propane pipeline, a nitrogen pipeline and a flue gas pipeline, the cooling water pipeline, the gas pipeline, the oxygen pipeline, the propane pipeline and the nitrogen pipeline are all connected with the oxygen combustion gun, the flue gas pipeline is connected with a smoke exhaust main pipe, the ignition device ignites propane, propane fire ignites coal gas, nitrogen is used for purging a gas pipeline, the safety of equipment is guaranteed, coal gas and oxygen are mixed and combusted, flame is sprayed out from a combustion port, scrap steel is directly preheated, cooling water is used for cooling an oxygen combustion gun, and a preheater conveys the scrap steel to the unloading unit after preheating is completed.

Specifically, the temperature acquisition units are respectively arranged on the inlet of the cooling water pipeline, the outlet of the cooling water pipeline, the gas pipeline, the oxygen pipeline and the inner wall of the ladle cover, the pressure acquisition units are respectively arranged on the gas pipeline, the oxygen pipeline, the nitrogen pipeline, the propane pipeline and the cooling water pipeline, and the flow acquisition units are respectively arranged on the gas pipeline, the oxygen pipeline, the nitrogen pipeline and the cooling water pipeline;

the pipeline adjusting valves are respectively arranged on a gas pipeline and an oxygen pipeline, and the pipeline pneumatic valves are respectively arranged on the gas pipeline, the oxygen pipeline, the propane pipeline, the nitrogen pipeline, the cooling water pipeline and the flue gas pipeline; the travel switches are respectively arranged at the upper limit position and the lower limit position of the oxygen combustion gun, the upper limit position and the lower limit position of the ladle cover and the in-place position of the preheater.

When the scrap steel preheating control system is used for controlling scrap steel preheating, the method comprises the following steps:

1) the travel switch reads the positions of the on-site ladle cover and the oxygen combustion gun, the temperature acquisition unit reads the medium temperatures of an inlet of the cooling water pipeline, an outlet of the cooling water pipeline, the gas pipeline, the oxygen pipeline and the preheater, and the pressure acquisition unit reads the medium pressures in the gas pipeline, the oxygen pipeline, the nitrogen pipeline, the propane pipeline and the cooling water pipeline;

2) the collected data information is transmitted to the controller, the controller transmits the data to the upper computer, and meanwhile, whether all data of the scrap steel preheating device are normal or not is judged;

3) if the alarm signal or the prompt message is not given normally, the site scrap steel preheating device is checked or overhauled, and then the step 1) and the step 2) are repeated;

4) if normal, each part of host computer control start steel scrap preheating device, the material loading unit transports the steel scrap to the pre-heater in, and oxygen fires rifle elevator motor control oxygen and fires the rifle and descend to the pre-heater in, and ladle cover elevator motor control ladle cover descends to the pre-heater upper end, ignition device strikes sparks, whether flame detecting element detects successfully striking sparks, and flame carries out the direct heating to the steel scrap, and each signal acquisition subassembly gathers the signal of preheating the in-process in real time, preheats the completion back, and ladle cover elevator motor control ladle cover rises, and oxygen fires rifle elevator motor control oxygen and rises, and the pre-heater transports the steel scrap that preheats to unloading in the unit, accomplishes the steel scrap and preheats.

Specifically, in the control process, the on-off and temperature flow of the cooling water pipeline are monitored in real time, signals of inlet and outlet valves of the cooling water pipeline are transmitted into the controller, and the system automatically monitors and ensures that the inlet and outlet valves of the circulating cooling water are in an open state. The temperature detection unit and the flow detection unit are arranged at the inlet and the outlet of the cooling water to transmit signals into the controller, and whether the inlet and outlet water temperatures and the flow of the cooling water are normal or not can be detected through the controller. When the temperature of the cooling water in the controller is alarmed, the system is required to cut off oxygen and gas so as to prevent the equipment from overheating. When the preheating task is not available on site, the cooling water valve can be adjusted to be small in order to prevent the cooling water from freezing in winter. The method mainly comprises the steps that in the preheating process, a ladle car added with scrap steel is driven into a preheating station to wait for preheating before preheating, whether all conditions on the site meet preheating conditions needs to be judged before preheating, the conditions before preheating on the site are transmitted into a controller by various detection devices, the judgment conditions are set in the controller, labor and time cost is saved, and reliability is guaranteed. The detection and control of gas, oxygen and propane are more critical, and the safety and working conditions of field production are directly influenced. Each step of the preheating process requires careful checking and evaluation. The on-site preheating takes the temperature of the roasted steel scrap and the temperature of flue gas in a hearth as reference control points, a temperature acquisition unit arranged on a furnace cover and a temperature acquisition unit in a flue gas pipeline transmit flue gas temperature signals into a controller, and the controller adjusts an output control valve through PID according to the setting mode of the preheating oxygen-fuel ratio of the steel scrap so as to control the flow rate of coal gas and the flow rate of oxygen, thereby achieving the purpose of controlling the temperature. Due to the fact that PID adjustment is used, the valve can be adjusted in a self-adaptive mode according to the set temperature and the actual temperature. The automatic control of the actual temperature of the flue gas in a set temperature range is realized.

The mixed combustion of oxygen and coal gas is an important part of preheating, the combustion needs to be automatically adjusted according to the temperature of flue gas, and when the temperature of the flue gas rises, the flow of the oxygen and the coal gas is reduced; when the temperature of the flue gas is reduced, the flow of the oxygen gas is increased. The proportioning coefficient of the coal oxygen can be controlled, the distance between the flame and the scrap steel is controlled, the flame strength can penetrate through the scrap steel, the oxidation of the scrap steel is reduced as far as possible, otherwise, the metal yield is reduced, and the next process requirement cannot be met. The control is carried out by adjusting the amount of the coal gas and the oxygen to an appropriate value, i.e. the lower the value, the better the combustion effect. Therefore, medium energy can be saved, effective preheating can be guaranteed, meanwhile, the temperature of the flue gas is reduced, the heat energy generated by combustion is effectively utilized, and the safety of a flue gas pipeline is also guaranteed. If the flame rushes out of the steel ladle and the ladle cover, the opening of a smoke exhaust valve is increased, or the flow of gas and oxygen is reduced, or the two are adjusted simultaneously. The site toxic and harmful gas leakage condition is monitored in a control room and a medium pipeline site, and sound and light alarm and prompt are sent out in time. If any gas of coal gas, oxygen and propane leaks on the site and reaches the set high alarm, the medium pipeline valve needs to be judged in time and closed, preheating is stopped, production needs to be carried out after detection and fault removal, and otherwise, inflammable, explosive and toxic accidents are easy to happen.

In order to realize different functions of the whole operating system, the upper computer comprises a master upper computer and a plurality of slave upper computers, in the embodiment, the master upper computer and the slave upper computers are respectively connected with the exchanger, the master upper computer is used for executing field monitoring and modification, the slave upper computers are used for process value acquisition, monitoring and report printing, and the exchanger adopts an industrial network of a TCP/IP protocol or Profibus.

And Siemens WinCC configuration software is installed in the master upper computer and the slave upper computers and is used as a graphical monitoring control terminal, and the master upper computer and the slave upper computers are respectively distributed with different authorities. The Siemens WinCC configuration software is used as a graphical monitoring control terminal and is used for realizing the unified monitoring of all equipment of the scrap steel preheating control system.

The selected SIMATIC WinCC uses the latest software technology. WinCC is the abbreviation of Windows Control Center, has realized the interconnection between automatic system and the IT system. WinCC is according to the process visualization system of price and performance grading, ability high efficiency control automation process. The switching operation of the pictures adopts the dynamic connection of the graphs, the functions set in the pictures are complete, the whole unit can be monitored only by operating the pictures, and the operation method is simple and convenient. When a fault alarm occurs, the information such as the time of the on-site condition, the on-site personnel, the time for solving the problem, the automatic adjustment time of the system after the problem is judged, and the like can be clearly seen by observing the alarm picture, so that the high level of the automation degree is really realized.

The controller is a Simatic S7-1500 or S7-300PLC, and adopts a TCP/IP and Profinet interface of the PLC.

The invention adopts TIA Portal 15.1 controller programming software to develop a control system, and the software supports a ladder diagram, a function block, a statement table and other multiple programming languages to develop the system.

The temperature acquisition unit is a temperature transmitter, the pressure acquisition unit is a pressure transmitter, and the flow acquisition unit is a flowmeter.

The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.