At the site of the pelletizing operating area of iron-making department of Shougang Jingtang Company, several pelletizing plates were rotating at a constant speed, and numerous raw pellets of the same size were sent to the belt continuously... All these were controlled by the operation staff with computers in the master control room.

In August 2010, the production line of belted pellet firing machine with a firing are of 504 square meters was completed and put into production by Shougang Jingtang Company. With the continuous improvement of the blast furnace smelting, the requirements of the blast furnace for the quality of the crude fuels were also getting higher. In the past, the artificial pelletizing method had certain shortcomings in the accuracy and timeliness of the operations such as the amount of feed, the amount of adding water, and the rotating speed of the pelletizers, becoming the biggest unfavorable factors that affected the quality of raw pellets. In view of this situation, Shougang Jingtang Company decided to implement an unmanned operation project of pellet intelligent control.

Aim at the target

“Intellectualization is the trend of the future development of iron and steel industry. We must focus on ‘quality’ and ‘intellect’ to develop stably, and add driving force to the transformation and development of Shougang,” said the head of Jingtang Company.

“The unmanned operation project of pellet intelligent control” came into being. Jingtang Company oriented its goal as “the demonstration production line of intelligent manufacturing in the pellet industry” to improve quality, reduce consumption and increase production efficiency through intelligent transformation of system. Iron-making department of Jingtang Company and technicians of Shougang Automatic Information and Technology Co., Ltd. immediately set up a project team to clarify the division of responsibilities, overall planning and schedule.

The control process of pellet production is a typical complex controlled object with a large number of uncertain information and diverse massive data, making traditional control methods less effective. The tackling team decided to aim at solving industrial autocontrol problems and developing automatic pelletizing technologies, so as to build a complete control system of intelligent pellet production.

Orderly advancement

 It is difficult to transform traditional production modes into intelligent ones. During the transformation, they divided the project into the control system of intelligent process and the information platform, including the establishment and debugging of nine sub modules such as the mixer water-filled automatic control module, the pelletizing automatic control module, and the intelligent ingredient module. The tackling team has conducted research and discussion on the system architecture, function implementation scheme, and data collection methods for many times to ensure the feasibility of the system functions, and the operation efficiency and effectiveness of the system. As for the establishment of pelletizing module, through real-time judgment and comprehensive analysis, automatically make correspondent adjustments to the moisture of raw materials and parameters including the water drawing amount, the feeding amount, the rotating speed of pelletizers and others during pelletizing according to model rules, to achieve the automatic control of production and size fraction of raw pellets.

Debugging in practical application is the most difficult part in transformation, so the project team decided to “pilot” with one pelletizing plate first and would copy it to other several machines if they succeeded. Thus, tests and adjustments were carried out in full swing. As for automatic control, the debugging of each individual process is very difficult, and it is much more difficult to achieve a perfect automatic operation by connecting all controls into one. For the various problems that arise in overall control, the research team checked carefully one by one through a large number of drawings, and worked together to find ways and ideas. With their joint efforts, the on-line debugging of the single-plate automatic control function of the No. 9 pelletizer was successful, and all automatic controls including automatic feeding, automatic water drawing, automatic adjustment of pelletizing and others were normal. Because of the great success, they continued to carry out transformation on the remaining pelletizers and fully realized expected functions of automatic control module of pelletizing.

Significant results

With the input of smart modules, the smart effects of all modules of the control system have become more prominent, making everyone pretty delighted.

Water-filling module of mixer can automatically adjust the amount of water supplemented, which achieved the water stability of the pelletizing raw materials; intelligent charging can remarkably reduce the number of raw material proportioning, and significantly improve the compositional stability of the finished pellets, especially the automatic pelletizing of the core part, from module operation effects. Under the premise of no significant fluctuations in the quality of mixture, automatic and stable pelletizing can be achieved, and the quality of the raw pellet is also significantly improved.

In addition, the project has also achieved results in energy conservation and consumption reduction. With the orderly operation of the modules, the energy consumption of the process and bentonite consumption are significantly reduced. After calculation, the energy consumption index of the process has decreased by 0.188 kg/ton with the annual benefit has reached about 450,000 yuan.

The implementation of the unmanned operation project of the pellet intellectualization, especially the realization of pelletizing auto control technologies, has filled the technological gap in domestic automatic pelletizing, and played a leading and demonstration role in promoting the intelligent production technology advancement of the pellets, improving product quality, and reducing production costs.