Dynamic modelling and optimal control of the primary and secondary drying stages of freeze drying of solutions in trays and vials

Author

Hasan Sadikoǧlu

Abstract

"Dynamic and multi-dimensional in space mathematical models were constructed and solved in order to describe quantitatively the dynamic behavior of the primary and secondary drying stages of the freeze-drying of pharmaceuticals in trays and vials. The theoretical results were compared with the experimental data of the freeze-drying of skim milk, and the agreement between the experimental data and the theoretical results is good.

The problem of operating a tray freeze dryer to obtain a desired final bound water content in minimum time is formulated as an optimal control problem with the use of the rigorous unsteady state mathematical models for freeze drying in trays and vials which were developed in this work. The heat input to the material being dried and the drying chamber pressure are considered to be the control variables. Constraints are placed on the system state variables by the melting and scorch temperatures during primary drying, and by the scorch temperature during secondary drying. Necessary conditions of optimality for both the primary and secondary drying stages are derived and presented, and an approach for constructing the optimal control policies that minimize the drying times for both the primary and secondary drying stages is presented.

Also, a novel "dynamic pressure rise" method is developed as a remote sensing procedure for determining at different times during the primary drying stage of the freeze drying process (i) the temperature of the moving interface between the dried and frozen layers of the product, (ii) the position of the moving interface, (iii) the temperature of the bottom surface of the frozen layer of the product, and (iv) the temperature profile of the frozen layer of the product "--Abstract, page iv.

Advisor(s)

Liapis, Athanasios I.

Committee Member(s)

Crosser, Orrin K.
Johnson, James W., 1930-2002
Reed, X. B., Jr.
Avula, Xavier J. R.

Department(s)

Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical Engineering

Sponsor(s)

Higher Education Council of Turkey
University of Missouri--Rolla. Biochemical Processing Institute

Publisher

University of Missouri--Rolla

Publication Date

Fall 1998

Journal article titles appearing in thesis/dissertation

• Mathematical modelling of the primary and secondary drying stages of bulk solution freeze-drying in trays: Parameter estimation and model discrimination by comparison of theoretical results with experimental data
• Optimal control of the primary and secondary drying stages of bulk solution freeze drying in trays
• Dynamic pressure rise in the drying chamber as a remote sensing method for monitoring the temperature of the product during the primary drying stage of freeze drying

Pagination

xii, 500 pages

Note about bibliography

Includes bibliographical references.

Rights

© 1998 Hasan Sadikoǧlu, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Subject Headings

Freeze-drying -- ResearchFreeze-drying -- Mathematical modelsDrying -- Mathematical modelsInterfaces (Physical sciences) -- Mathematical models

Thesis Number

T 7535

Print OCLC #

41441464

Electronic OCLC #

933734795

Recommended Citation

Sadikoǧlu, Hasan, "Dynamic modelling and optimal control of the primary and secondary drying stages of freeze drying of solutions in trays and vials" (1998). Doctoral Dissertations. 1281.
https://scholarsmine.mst.edu/doctoral_dissertations/1281