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Abstract

Содержание

Introduction

In the refractory industry, high‑temperature production units are of great importance. The use of such production facilities is associated with the consumption of a large amount of electric energy or fuel for heat generation. Among the necessary production tasks that began to be solved already since the invention of the first industrial furnaces, one can single out a reduction in the consumption of electric energy or fuel consumption.

In technical systems, the use of automatic control systems (ACS) is constantly expanding. The development process of self‑propelled guns is required to increase flexibility and dynamism, reduce the consumption of temporary, material and intellectual resources.

Rotary kilns are widely used in various industries. Rotary kilns belonging to the number of industrial continuous kilns with movement around the longitudinal axis have different purposes – melting, drying, thermal, roasting, etc.

The primary material placed in rotary kilns should move along the kiln, with a gradual increase in temperature due to the heat that is released during the combustion of gas. Along the length of the furnace, a variable thermal regime is observed. The main advantage of a rotary kiln is its rather high efficiency. A rotary kiln is able to fully provide in‑line production as an intermediate technological link.

The productivity of a tubular rotary kiln primarily depends on the length, diameter, as well as the slope and speed of the rotary kiln, the material of which the inner surface is made, and other characteristics of the calcined material.

1. Theme urgency

Improving the automatic control system of a tubular rotary kiln makes it possible to solve a number of problems, such as:

1. Maximum use of the heat of combustion of fuel for firing fireclay;

2. Exact observance of technological parameters of a rotary kiln in order to obtain high‑quality fireclay;

3. Prevention of dust emission from the furnace in order to ensure an environmentally cleaner environment around the enterprise;

4. Increase the service life of all mechanisms and heat exchangers.

2. The purpose and objectives of the study, expected results

Due to the fact that the rotary kiln consumes fuel in large volumes (10–30% of the mass, which is 2000–2200 m3/h), that is, the need to optimize fuel consumption.

The main goal of creating a system is to regulate the temperature regime of a tubular rotary kiln to regulate the supply of gas and air, which affects the technical and economic indicators of production.

A number of tasks were set to develop an automatic control system.

  1. The design task is to select the necessary sensors, actuators and controller in compliance with classical accuracy;
  2. The task for management is to achieve effective fuel consumption while maintaining the quality and volume of products;
  3. Information task – to provide continuous two-way communication with the control center.

3. Development of the structural diagram of аutomatic control systems

Using the results obtained in the analysis of a tubular rotary kiln as a control object, discussed in the first paragraph, taking into account the concept of ACS construction, we will develop a structural diagram of an ACS with a rotary kiln.

The work of self‑propelled guns is to maintain the temperature in the firing zone equal to 1720 °С, for this an optimal ratio of gas and air supply is necessary.

In the presence of a disturbing effect, the temperature begins to change, this will lead to the fact that the error starts to grow and, as a result, causes an increase in the voltage supplied to the actuator. The actuator will begin to rotate by turning the flapper, which will cause a change in gas flow. Knowing the changes in the gas supply, the signal is supplied to the air supply regulator. The voltage supplied to the actuator will increase, the damper will turn, which will affect the change in air supply.

Conclusion

An analysis was made of the control object – a rotary kiln, and the features of the object in question were determined. During the analysis, the goals of creating an automation system were formulated, the functions and tasks of the future automation system were described.

A model of a rotary kiln is developed. It is shown that the required control efficiency of a rotary tube furnace to maintain the optimum temperature in the firing zone by maintaining the optimal ratio of gas and air supply is achieved using the built self‑propelled guns.

References

  1. Теплотехника металлургического производства. Т. 2. Конструкция и работа печей: Учебное пособие для вузов/Кривандин В. А., Белоусов В. В., Сборщиков Г. С. и др. – М.: МИСИС, 2001. – 736 с.
  2. Лисиенко, В. Г. Вращающиеся печи: теплотехника, управление и экология Кн. 1: Справ. изд.: В 2 кн. / В. Г. Лисиенко, Я. М. Щелоков, М. Г. Ладыгичев; Под ред. В. Г. Лисиенко. – М.: Теплотехник, 2004. – 690 с.
  3. Бельский В. И., Б. В. Сергеев Б. В. Промышленные печи и трубы. Учеб. Пособие для техникумов. Изд.2–е, испр. и доп. М., Стройиздат, 1974. 301 с.
  4. Компания Липецкстальпроект. Автоматическая ситема управления вращающейся печи обжига [Электронный ресурс] URL:http://lsp48.ru/proekty/razrabotki
  5. Научно–производственное предприятие «Микролог. МЛ 515 Система автоматизированного контроля и управления для вращающихся печей обжига [Электронный ресурс] URL:http://microlog.km.u...
  6. К. Марута . Особенности горения газа в узком нагретом канале//Физика горения и взрыва. / Дж. К. Парк, К. С. Ох, Т. Фуджимори, С. С.  Минаев, Р. В. Фурсенко – 2004. №5 128 с.
  7. Голдсуорт Б. Проектирование цифровых логических устройств / Б. Голдсуорт. М.: Машиностроение, 1985. – 288 с.