Optimal operation and feedback control for complex industrial process

With ever increased needs for an improved product quality, production efficiency, and cost in today´s globalized world market, advanced process control should not only realize the accuracy of each control loops, but also has the ability to achieve an optimization control of production indices that are closely related to the improved product quality, enhanced production efficiency and reduced consumption. As a result, the optimal control of complex industrial process has attracted an increased attention of various process industries. This paper firstly introduces the research stare-of-art and existing problems for optimal operation of industrial processes, and then presents the meanings for optimal operation control. In view of the characteristics of complex industrial processes, a hybrid intelligent control method for optimal operation is proposed, which is composed of a control loop pre-setting model, a feed-forward and feedback compensators, a production index prediction model, and a fault working-condition diagnosis unit plus a fault-tolerant control model. When production condition and working condition changes, this method can adjust the set points of control loops adaptively so that production index can be controlled in its target range. This paper also presents an application case study of this method in the roasting process of a shaft furnace for the ore concentration industry. Shaft furnace is a facility which is used widely in the ore concentration industry to turn the weak-magnetic low-grade hematite ore into strong-magnetic one. The target of optimal operation control for the roasting process of shaft furnace is to control the production indices, namely the magnetic tube recovery ratio (MTRR) that represents the quality, the efficiency, and the consumption of the product processing, close to its target value within limited ranges, and to make it as high as possible. The proposed optimal operation control method in this paper has been applied to the roas- ting process undertaken by 22 shaft furnace in Jiugang Ore Concentration plant of China. It has been shown that the MTRR is controlled to the rational range around the target value, with a result of 2% increase; the equipment´s operation ratio is enhanced by 2.98%, resulting in a raise of 0.57% in concentrated grade and 2% in metal recovery rate. Such an industrial application has successfully demonstrated the performance of the proposed optimal control method which will therefore has a high potential for further and much wider applications.