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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