Realization of three-level system of control and management of quality of production through automation of technological process

Table of contents: The Kazakh-American Free University Academic Journal №1 - 2010

Author: Abitova Gulnara, Eurasian National University in honor of L. Gumilyov, Kazakhstan

Under the current stages of economic development, optimal and efficient control of fixed assets is viewed as one of the main tasks in the development of any industrial enterprise in any country.

Modern control methods are suitable for increasing production capabilities of such enterprises by employing information technologies, which are often used for modernization of industrial processes without the need of acquiring new expensive equipment.

As a rule, these technologies are tightly integrated with automatic control systems for technological processes, and by doing so we are able to reduce the cost of service of fixed assets, increase production capabilities of the manufacturing processes, reduce equipment down time, achieve better personnel management and better control of the entire enterprise.

Therefore, automation of the industrial processes is one of the most important directions of the technological progress as it leads to improvement, modernization, and intensification of industrial processes [1].

Currently, physical and chemical processes used in industrial production of tellurium are very well known and have been tested by many years of practice. Obtaining tellurium from lead-containing products in the industrial environment is viewed as a very sophisticated physical and chemical process.

It requires special control systems to maintain all technological regimes within pre-defined bounds, and the associated state observation and regulation relies on a large number of devices, sensors and actuators [2].

The technological process of tellurium production includes a number of stages, which require automatic regulation of many parameters with a high degree of precision. Some of the parameters, for example, the flow of technological fluids, the level of technological fluids in a reactor, the color of pulp during the sulfation process, weight characteristics of dry materials on different technological levels, must be controlled.

In previous practice, a widely used regulation approach relied on controllable valves and pumps working at full capacity for supplying fluid components at the required rates, dry products were typically measured on the scales, and control of the color of pulp was based on visual estimation by the operator involved in the industrial process [3].

Without full compliance with the requirements of technological discipline, incorrect measurements of the liquid components, error in estimation of the quantities of dry products, and other errors, can lead to improper balance of materials in the physical and chemical processes, which, in turn, results in lost valuable products or sub-standard quality. Under this technological control approach, the purity of the commercial product cannot exceed 99.96%, which is insufficient, for example, for the metals used in semiconductor devices.

In this work, we analyze and propose a unified concept of application of modern means of automation that can be used to build a three-level hierarchical control system intended for assuring the product quality [3]. It can be viewed as having three levels of control. It is demonstrated on the picture 1.

Picture 1

Sensors and devices that monitor technological parameters and the state of equipment, as well as other mechanisms and actuators, form the first, or lowest, level of the proposed automatic control system.

This can be achieved with the following systems: directly controlled asynchronous electric drives for technological fluids, qualitative control of the pumps used on the extraction stage, vector speed control of the electric drives for technological fluid pumps, vibro-dosimeter of dry reagents, etc.

On the second, or middle, level we have modern microprocessors that can be used to collect, process, and analyze analog information from sensors and devices of the first level, calculate control efforts and apply those to the actuating mechanisms in accordance with selected control criteria.

Calculation of control signals, algorithm programming, and mathematical models, which account for both normal and abnormal (emergency) operation regimes, were implemented on the basis of a SIMANTIC S7-300 microcontroller by Siemens. It is demonstrated on the picture 2.

Picture 2

Implementation of “intelligent” automated work stations for technological personnel requires the third level of automatic control, which is based on modern personal computers, network applications for PCs, and appropriate software support.

Those components are used to maintain continuous monitoring of the technological equipment, to track major dynamic characteristics of the physical and chemical processes, to display graphically the current state and working regimes of the main technological equipment, to extrapolate the state of technological process with an emphasis on possible emergency situation.

The automation system of the third level can be integrated into a centralized system that analyzes the state of metallurgical processes and can be used to perform optimal control of production of lead and zinc-containing products across the entire metallurgical complex [4].

In this paper, we present a complex approach to the problems of first-, second-, and third-level, formulate and demonstrate the need to create a complex automation system with a three-level hierarchy for monitoring and control of a single technological process and of the entire plant.

This approach is required to stabilize parameters of different regimes of the technological process, to obtain objective information about the state of the process, and to increase control efficiency of the technological cycle.

This theoretical solution and scientific formulation of the existing problem can be used to improve many technological processes used in the metallurgical complex and to increase the quality of end products [5].

As a result of this research and analysis, we offered a unified concept of realization of modern automation techniques by employing three-level hierarchical monitoring and control of manufacturing processes.

The obtained theoretical results were tested and proposed for implementation in a chemical metallurgy line of refining and affinage, where higher ratios of extraction of useful components were confirmed.

LITERATURE

1. Abitova G.A., Pavlov A.V., Belgibayev B.A., Ushakov N.N. О совершенствовании технологии извлечения теллура из плавов свинцового производства. // Complex use of mineral raw product. – Almaty: Publishing house Galim, 2004. - №6. - p. 63-68.

2. Abitova G. A., Tarasuk I., Shahmuhambetov B.A. К задаче оптимизации расходных характеристик в технологических трубопроводах. // Collection of scientific works – Ust-Kamenogorsk: Publishing house of East Kazakhstan State University, 1997. - p.6-8.

3. Belgibayev B.A., Abitova G. A. Гибридная модель в управлении гидрометаллургическими процессами. // Collection of scientific works – Ust-Kamenogorsk: Publishing house of East Kazakhstan State University, 1997. - p.3-5.

4. Belgibayev B.A., Abitova G. A. Оптимизация экстракционного процесса получения теллура на базе программно-аппаратных средств фирмы SIEMENS. // Herald of National Science Academy of the Republic of Kazakhstan– Almaty. Publishing house "National Science Academy of the Republic of Kazakhstan", 2004. №2. – p. 93-96.

5. Abitova G.A. Оптимизация технологических процессов современных промышленных предприятий на основе создания пакета прикладных программ // Materials of international scientific practical conference – Ust-Kamenogorsk: Publishing house of East Kazakhstan State University, 2002. – p.192-194.



Table of contents: The Kazakh-American Free University Academic Journal №1 - 2010

  
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