Operating performance assessment of between-mode transitions for multi-mode plant-wide process

The assessment of operational performance evaluates the degree of online optimality of the process behavior and identifies the causes of non-optimality. However, transitions between modes during performance evaluation is often overlooked and difficult to evaluate. In this paper, the following practical issues are considered, namely, the plant-wide process properties, the multiple working mode characteristics, and the coexistence of quantitative and qualitative information. An Operating performance assessment with between-mode transitions is proposed in this research. The characteristics of intermodal transitions are analyzed to determine the factors that affect performance. To tackle the plant-wide properties, a process is divided into several sub-blocks according to the process physical properties horizontally. Then operating performance is classified into sub-block level and global level vertically. The sub-blocks are modeled and evaluated individually, which together with the between-mode transitions modeling and evaluation constitute the global level evaluation. In between-mode transitions, the features of the average optimal trajectory are extracted as for the evaluation. Finally, the proposed method is applied to the gold hydrometallurgical process to examine its assessment behavior.