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Decomposition of thermally unstable substances in film evaporators

Journal Article:

Abstract

It is widely known that film evaporators are considered to permit really gentle evaporation of heat-sensitive substances. Nevertheless, decomposition of such substance still occurs to an extent depending upon the design and operation of the evaporator. In the following a distinction is made between evaporators with films not generated mechanically, namely the long tube evaporator (lTE) or climbing film evaporator, the falling film evaporator (FFE) and the multiple phase helical tube (MPT) or helical coil evaporators (TFE). Figs 1 and 2 illustrate the mode of operation. A theory of the decomposition of thermally unstable substances in these evaporators is briefly outlined and compared with measurements. Such a theory cannot be developed without any experimental checks; on the other hand, meausrements urgently need a theoretical basis if only to establish what actually has to be measured. All experiments are made with a system of readily adjustable decomposability, namely with aqueous solutions of saccharose; the thermal inversion of this compound can be controlled by addition of various amounts or concentrations of hydrochloric acid. In the absence of any catalysis by hydrochloric acid, the decomposition rates within in the temperature interval studied (60-130/sup 0/C) are so low that the experiments would take much  More>>
Authors:
Publication Date:
Oct 01, 1982
Product Type:
Journal Article
Reference Number:
DE-88-007308; EDB-88-123508
Resource Relation:
Journal Name: Ger. Chem. Eng. (Engl. Transl.); (Germany, Federal Republic of); Journal Volume: 5:5
Subject:
42 ENGINEERING; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; EVAPORATORS; FILMS; SACCHAROSE; DECOMPOSITION; AQUEOUS SOLUTIONS; COMPARATIVE EVALUATIONS; DISTILLATION; LIQUID FLOW; MEDIUM TEMPERATURE; QUANTITY RATIO; TEMPERATURE DEPENDENCE; THERMAL DEGRADATION; CARBOHYDRATES; CHEMICAL REACTIONS; DISACCHARIDES; DISPERSIONS; FLUID FLOW; MIXTURES; OLIGOSACCHARIDES; ORGANIC COMPOUNDS; SACCHARIDES; SEPARATION PROCESSES; SOLUTIONS; 420200* - Engineering- Facilities, Equipment, & Techniques; 400800 - Combustion, Pyrolysis, & High-Temperature Chemistry
OSTI ID:
7199274
Research Organizations:
Bayer A.G., Wuppertal (Germany, F.R.)
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: GCETD
Submitting Site:
DE
Size:
Pages: 278-291
Announcement Date:
Jun 01, 1988

Journal Article:

Citation Formats

Matz, G. Decomposition of thermally unstable substances in film evaporators. Germany: N. p., 1982. Web.
Matz, G. Decomposition of thermally unstable substances in film evaporators. Germany.
Matz, G. 1982. "Decomposition of thermally unstable substances in film evaporators." Germany.
@misc{etde_7199274,
title = {Decomposition of thermally unstable substances in film evaporators}
author = {Matz, G}
abstractNote = {It is widely known that film evaporators are considered to permit really gentle evaporation of heat-sensitive substances. Nevertheless, decomposition of such substance still occurs to an extent depending upon the design and operation of the evaporator. In the following a distinction is made between evaporators with films not generated mechanically, namely the long tube evaporator (lTE) or climbing film evaporator, the falling film evaporator (FFE) and the multiple phase helical tube (MPT) or helical coil evaporators (TFE). Figs 1 and 2 illustrate the mode of operation. A theory of the decomposition of thermally unstable substances in these evaporators is briefly outlined and compared with measurements. Such a theory cannot be developed without any experimental checks; on the other hand, meausrements urgently need a theoretical basis if only to establish what actually has to be measured. All experiments are made with a system of readily adjustable decomposability, namely with aqueous solutions of saccharose; the thermal inversion of this compound can be controlled by addition of various amounts or concentrations of hydrochloric acid. In the absence of any catalysis by hydrochloric acid, the decomposition rates within in the temperature interval studied (60-130/sup 0/C) are so low that the experiments would take much too long and determination of the concentration differences (generally by polarimetric methods) would be very complicated. Such slight effects would also be very unfavourable for comparison with theory. (orig.)}
journal = {Ger. Chem. Eng. (Engl. Transl.); (Germany, Federal Republic of)}
volume = {5:5}
journal type = {AC}
place = {Germany}
year = {1982}
month = {Oct}
}