Abstract
Content
Introduction
Computers penetrate deeper and deeper into our lives. They are indispensable in the field of space research, telecommunications, medicine, metallurgy, information technology and industry. The main directions of economic and social development becomes a task to develop the production of electronic control devices and remote control, actuators, instrumentation and sensors integrated automation systems of complex technological processes, machines, machinery and equipment. The experience gained in the creation of automated and automatic control systems, shows that different process management based on a number of rules and laws, some of which is common to the technical devices, living organisms and social phenomena.
The present level of development of hardware (hard-wear) and software (soft-wear) tools developed enough to create a process control system. Limiting the development of steelmaking process control systems third necessary component - substantial part of the (brain-wear), which describes itself control problem and the method of their solution. Brain-wear - remit domains professionals who know what's going on in the unit and how it should work, and therefore able to determine how and what to automate. A key factor in determining the quality of the entire control system, is the efficiency of this part - the decision-making procedure.
The most reliable and effective method is the use of a mathematical model that describes all of the processes occurring in the managed object, it allows you to predict the course of the process and to determine the necessary manipulations.
However, until recently it was not possible to create a mathematical model that adequately adequately and accurately describing the heat and mass transfer processes that make up the essence of the steel smelting. This hampered the complexity of these processes and an abundance of factors that affect their leakage.
The lack of such a model and did not allow to achieve significant progress in the development of PCS steelmaking units.
Theme urgency
At the present stage of development of metallurgical enterprises, steelworker has no time to consider all the factors and conditions of production, which leads to frequent errors in management, and steelmaking unit is a highly-complex, which includes, besides the main reactor (EAF, converter, ladle), a number of subsidiary devices (dosing and loading devices, lances, burners, controllers, motion control systems of electrodes, arc characteristics, etc.). All of these devices are equipped with highly sophisticated local automation tools, which together form the so-called first tier (or hardware) management. The existing first-level systems allow with sufficient reliability to realize all the process steps of melting the signals coming from the operator or from the management of the second-level system whose primary function is to develop solutions for process control and optimization.
Process control using the PCS, as it is known, is based on the simulation, this function is performed by the forecast module, based on a system of equations - mathematical model of the process. This module predicts composition smelting products based on the data loaded into the furnace material. The quality of this module determines the performance and capabilities of the total management system. In developing optimal solutions for the management of the process is the same system of equations is solved in the opposite direction: the composition of the metal is given, and there are optimum values of the input (control) parameters at minimum (or maximum) value of the output parameter selected as the target function, for example, with a minimum total costs of materials and energy.
More modern intelligent system allows, in particular, to realize the principle of control situation, which is schematically composed as follows. Process Management and smelting furnace treatment begins with designing the next heat. As the input data used by the brand (or part of) steel, a list of materials available in the warehouse, equipment specifications and additional restrictions dictated by the conditions of production (equipment condition, condition related added value, policy constraints, etc..). After receiving the job smelting process control system provides the estimated schedule of future fusion with detailed study of all the modes of operation of the governing bodies, the optimum mass of input materials, the full costing for redistribution, and the message technology, provides services, and the other at a pre-agreed list. When you receive comments, this procedure is repeated until the complete harmonization. After obtaining consent (or default), APCS at the appointed time to begin implementation of the plan, continuously tracking the current interim results in relation to the settlement (the actual sensor readings, temperature measurements, chemical analyzes received, etc..). In the event of significant deviations from the estimated schedule PCS signals it repeats the calculation taking into account the changed conditions, is negotiating and continues to melt on a modified schedule. At any time, the operator can take control or return to automatic mode. During the transition to manual control automation systems continues to work in the same mode, taking into account further action steelmaker, bringing their recommendations to the screen, ie, in advisor mode, while remaining ready to take back control "over."
A number of process parameters necessary to control, we can not introduce in advance as they are specific to each unit and, most importantly, change over time (kinetic coefficients of thermal efficiency, the effectiveness of blowing devices, etc.). Their meanings can only be found through statistical data processing array heats the past related to this unit. The accumulation of such factors and their use as "constant" or "characteristic values" can lead to significant errors in the management of time inconsistency (the height of the lining wear or replacement of individual units of equipment, the heterogeneity of incoming raw materials, seasonal changes, etc. ).. In such systems, all necessary for the coefficients are determined by a limited array of heats and last updated at the end of each heat. This allows for planning the next melting use not only the most reliable values, constants, and if necessary to consider their tendency, variance and other statistical characteristics. This function is performed by the system of dynamic adaptation.
The control system fuse, built on the basis of physico-chemical model, in real time generates technological solutions, supporting the work of the unit in any "emergency" situations (emergency shut-down equipment employment, lack of material, etc.) that are compatible with the fundamental possibility the fulfillment of the tasks (preparation of a given composition and temperature of the metal). The adequacy of the control commands of the system is ensured by the feedback (adaptation, self-study). In addition, there is an opportunity to "play" a variety of options when designing a new smelting technology - function, fundamentally inaccessible to statistical models.
Conclusion
ACS can be used in the management of a variety of steel production processes, but above all it should be applied at key stages of the process chain - to control the melting in EAF and ladle handling.
References
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