Temperature Inferential Control of Heat‐Integrated Distillation Column Based on Variable Sensitive Stage Temperature Set‐point

Abstract

Heat‐integrated distillation is an improved distillation technique with remarkable energy‐saving potential. A control scheme with a variable sensitive stage temperature set‐point is proposed to solve the control problem of a heat‐integrated distillation column (HIDiC). An online estimator is designed to support the variation of the set‐point. The locations of the stage temperature measurements are carefully selected based on a combination strategy with three steps. First, the sensitive stages are selected. Then, the following stages are determined by a PCA‐based method. Finally, a maximum differentiation method provides the remaining measurement selections. According to the profile parameters estimated by the proposed estimator, the set‐point of the sensitive stage temperature is adjusted adaptively to reduce the influence of the disturbances. Two commonly‐used PID controllers, the sensitive temperature control and the temperature differential control, are developed as the comparative study. The simulation results show that the proposed control scheme has a distinct advantage in restraining different disturbances.

Adaptive Temperature Control for Distillation Columns Based on Relative Stability in the Profile Pattern

“…However, when the profile pattern changes largely, it will affect the performance of CS1. For example, when the feed composition disturbance is involved, CS1 is less efficient than CS2-1 and CS2-2, as shown in Figures 12,14,and 15. In CS2-1 and CS2-2, the position of the inflection point is derived based on the mass-transfer mechanism.…”

“…The defects of online composition measurements limit the utilization of the composition control. Therefore, temperature inference control occupies a dominant position in distillation control. − Typically, some intermediate stage temperatures are chosen as the controlled variables with specific criteria, in which the selection of sensitive stage temperature is widely used. , This type of control strategy is very effective when the distillation column works around a specific state. However, product purity offsets may occur if the plant encounters large disturbances, especially when the column has a complex structure with strong nonlinear dynamics.…”

Reduced-Order Modeling and Control of Heat-Integrated Air Separation Column Based on Nonlinear Wave Theory

“…Hence, empirical functions can be used for fitting. Empirical functions with substantial verification in the separation process are introduced for the waveforms of the high-pressure and low-pressure columns [42]:…”