Control structures for disturbance rejection and decoupling of distillation

Abstract

The process gains for different distillation control structures can be calculated through transformations from known gains of one arbitrary structure.In this paper the transformation is utilized for calculation of a two-point distillation control structure which, in the steady state, simultaneously rejects disturbances in the feed composition and in the feed flow rate and results in implicit decoupling between the two product control loops. This disturbance rejecting and decoupling (DRD) structure is tested on a model of a 15-plate pilot-plant distillation column. It compares favorably with standard structures for dual composition control. Experimental results agree with the simulation results.

Quantitative methods for optimal regulatory layer selection

“…Note that we have steady state degrees of freedom n u = 2. For this distillation column in LV-configuration [Häggblom and Waller, 1990]…”

Comparison of advanced distillation control methods. Third annual report

“…Feed composition changes usually represent the most challenging disturbance for distillation column control on a regular basis. The (L,V) Configuration has been found to offer significant advantages for rejecting feed composition disturbances (e.g., Haggblom and Waller, 1990). This results because the energy required to meet product specifications does not usually change a great deal for feed composition changes while the D/B ratio does.…”

Comparison of advanced distillation control methods. Second annual report

“…Feed composition changes usually represent the most challenging disturbance for distillation column control. The (L,V) configuration has been found to offer significant advantages for rejecting feed composition disturbances (e.g., Haggblom and Waller, 1990). This results because the energy required to meet product specifications does not usually change a great deal for feed composition changes while the D/B ratio does.…”