A New Class of Model-Based Static Estimators

Abstract

Static estimators are commonly used as "soft sensors" in the process industry. The performance of the estimators is dependent on whether it is used for monitoring (open-loop) or for closed-loop control applications. In this work, we propose to design estimators that are specialized for each case. The approach is to minimize the estimation error for expected disturbances and measurement noise. The main extension, compared to previous work, is to include measurement noise and to provide explicit formulas for computing the optimal static estimator. We also compare the results with standard existing estimators (e.g., partial least-squares (PLS)). The approach is applied to estimation of product composition in a distillation column from a combination of temperature measurements.

Self-optimizing control – A survey

“…These should be kept at their optimal setpoints such that the primary variables assume their optimal values. Using self-optimizing control concepts, Ghadrdan et al (2013) designed a static estimator that minimizes the closed-loop prediction error for such a case.…”

Design and control for a dividing‐wall column with a partial condenser for pretreating an industrial multi‐component reformed gasoline mixture

“…[13] As shown in Figure 1b, the DWC can be divided into four sections by a wall, creating the pre-fractionation section, common rectifying section, common stripping section, and main separation section. [14] Avoiding the remixing effect leads to higher thermodynamic efficiency and ensures higher purity of the side product stream. [15] Because of the significant benefits on investment costs and energy savings, the DWC has been gradually adopted in industrial applications, e.g., extractive distillation, azeotropic separation, and reactive distillation.…”

“…[32] Although the interactions of design and control are ignored, the sequential approach has been shown to be very effective in the distillation process' design and control. [12][13][14][15][33][34][35] Although some general guidelines and rules for DWC control have been recommended, [36] researchers are putting increasing efforts into the controllability and process dynamics' understanding of DWCs. [37][38] The simplest control structure is the threepoint control structure.…”

Dynamic compensation of static estimators from Loss method

“…Commonly, simple linear relationships,ŷ = Hx, are used to estimate composition (y) based on temperature measurements (x). Ghadrdan et al Ghadrdan et al (2013) have presented the optimal estimators for different control applications. They are optimal in the sense that they give minimum error for the estimation of primary variables at steady-state in the presence of disturbance and noise.…”