Targeting on Different Characteristic Continuous Variables in Process Transition for Ethylene Column with Wide-Range Feed Fluctuation

Abstract

For the study of the transition strategies of continuous chemical processes, both continuity and dynamic characteristics in the physical sense are critical. The continuous transition strategy has a higher information density and can describe the real situation as closely as possible. In addition, the accuracy of the dynamic characteristics is necessary because the process transition is the study of the dynamic system processes. However, existing transition strategies have certain shortcomings. Dynamic optimization can obtain transition strategies with different characteristics but no physical meaning and a frequency domain-based analytical approach can acquire a continuous transition strategy with physical meaning, but its dynamic characteristics are the same. Therefore, by integrating the advantages of the existing strategies, a new transition strategy has been presented, which possesses different dynamic characteristics and continuity synchronous with physical significance. When process transition occurs, the proposed strategy results in less fluctuation and can quickly reach and maintain a steady state. Furthermore, the strategy is also suitable for the rapid application of different transition processes in the same plant. The performance of the transition strategies is evaluated through research on a continuous feed ethylene column.

Novel feedforward‐feedback‐based continuous process transition strategy for chemical industry

“…Compared with the former method, the latter method can get continuous analytical solutions with different characteristics, which has higher accuracy. 16 Thus, the frequency-domain-based two-step optimization approach is generally selected to compute the transition problem, the schematic diagram of which is displayed in Figure 5.…”

“…14 Because of the effect of discrete accuracy, the numerical solution may ignore some local details, which in turn has adverse impacts on the transition process. The frequencydomain-based analytical method and frequency-domainbased two-step optimization approach developed by Cao et al 15,16 have addressed the above defects. The transition strategy acquired by these two methods has physical continuity, which further enhances the accuracy and practicality of the transition strategy.…”