PU – Schaum - Recycling: Machbarkeitsstudie zur Rückgewinnung von Polyolen aus einem komplexen Reaktionsgemisch

Research output: ThesisMaster's ThesisResearch

Authors

Abstract

The degradation of flexible PUR-foams using selectively cracking chemical compounds, such as enzymes, is a new approach for the reclamation of secondary products of preferably high purity. In this thesis, the aim was to find a reasonable way for the separation of raw materials, such as polyols and amines, out of an aqueous solid-liquid-mixture, which has been produced by enzymatic degradation. Long-term objective of the project for PUR-foam-recycling is the recirculation of the separated compounds as secondary raw materials into the production process without any deterioration in quality. The objective of this thesis was to show the existing state of the art for the separation of the available solid-liquid-mixture in the framework of a feasibility study and to evaluate the suitable separation techniques, particularly membrane processes and thermal separation processes regarding efficiency and complexity. The most promising method, the liquid-liquid-extraction with organic solvents (diethyl ether, dichloromethane, petroleum ether and n-hexane), has been investigated in a test series on laboratory scale in terms of industrial applicability. Therefore, tests have been made with mixer-settler-reactors, as well as with extraction columns, varying various process parameters, such as the amount of solvent, the extraction time and the pH-value. After thorough evaluation, especially diethyl ether and dichloromethane proved to be suitable solvents. With these two solvents, significantly high yields of polyols have been obtained with only one extraction step. Additionally, analysis via GC-MS showed that both solvents are characterized by high selectivity, especially in combination with acidic and alkaline shaking. Based on the gained knowledge of this thesis, suggestions and alternatives for further proceedings have been gathered and a possible implementation on a commercial scale of the whole process is discussed.

Details

Translated title of the contributionPUR – Foam - Recycling: Feasibility study for the reclamation of polyols from a complex reaction mixture
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
Award date28 Jun 2013
Publication statusPublished - 2013