In recent years, the cement industry has been relying on digital and intelligent means to improve quality and efficiency, save energy and reduce emissions, and accelerate the realization of "intelligent manufacturing" of cement. So what is the overall level of intelligent control in the cement industry? How much benefit can it bring to cement enterprises? In this regard, China Cement Network interviewed Professor Zhu Yucai, Department of Control, Zhejiang University.
"Intelligent control in cement plants has obvious economic benefits, which can not only save coal and electricity by 1% -5%, but also improve the safety and stability of the whole production process." Zhu Yucai said that, however, the intellectualization of China's cement industry is still in its infancy, and only more than 100 clinker cement production lines have been intelligently controlled, accounting for no more than 10%.
Zhu Yucai believes that the basic requirement of intelligent control is to reach the level of automation first, but 90% of the clinker production lines in China can not reach the level of advanced automation production, and there are still many problems.
It is understood that the intelligent operating system currently seen in the cement industry mainly includes PID, expert control system, model predictive control system, etc. How to choose the use of intelligent control system for the cement industry?
Zhu Yucai said that PID is a single-variable control method, and the cement production system is affected by coal, wind, material and other factors, the use effect in the cement plant is not good, so many people do not use it. The expert control system is to computerize an experienced master and then replace the experienced person, which will be better than some inexperienced operators. However, in fact, experts can not quantitatively describe their own experience, and it is difficult to accurately computerize, so this expert control system has not been very successful in China for 30 years.
"Model predictive control system first establishes a model through system identification method, also known as transfer function matrix, and then predicts the future trend of the device online based on this model, and then formulates the control scheme." Zhu Yucai introduced that at present, this control technology is widely used in petrochemical and chemical industries.
According to Zhu Yucai, for cement plants, after the model predictive control system is put on line, there is a lot of room for energy saving and emission reduction with large fluctuations in the original production system, and the relatively stable energy saving and emission reduction range of the original system is small.
"If the temperature of the decomposition furnace fluctuates by 30-40 degrees, we can save coal by 3% -5%.". If the fluctuation is 10 degrees, the coal saving will be about 1%. Zhu Yucai said that the model predicts that the intelligent operating system can save coal and electricity by 1% -5%, and can save 4 million to 8 million yuan annually according to the production line with a daily output of 5000 tons. In order to make full use of the potential of model predictive control technology, it is suggested to install on-line detection instruments such as gas analyzer in smoke chamber and temperature measurement in kiln. It will be better if on-line analyzers for raw meal and free calcium oxide can be installed. Zhu Yucai suggested.
To this end, China Cement Network will hold the Fifth China Cement Intelligence Summit Forum in Hangzhou on November 29, 2023 with the theme of "Data-Driven Decision-Making Intelligence Leads the Future". At that time, Professor Zhu Yucai of Zhejiang University will be invited to give the theme report of "Model Predictive Control and Operation Optimization of Cement Production Line". Welcome to actively participate in the exchange and discussion, and jointly promote the intelligent process of the cement industry.
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