Fried. Krupp Gesellschaft MIT Beschrankter Haftung

Fried Krupp

Fried Krupp Ag Hoesch-krupp

Klaus Reimann

Rainer Hagen

Hubert Coenen

Hedi Ben-Nasr

Ernst Kriegel

Manfred Grabow

Hedi B Nasr

Hubert Jasper

Eckhard Haeffner

Bernd Knuth

A process for treating an impure thermoplastic polymer, including raw and recycled polymers, during extrusion to separate low molecular weight compounds therefrom, including: introducing a separating agent into plasticized impure thermoplastic polymer passing through a first high pressure zone, the low molecular weight compounds of the plasticized polymer being at least partially soluble in the separating agent; extracting at least a part of the low molecular weight compounds from the plasticized polymer into the separation agent during passage of the plasticized polymer through an extraction zone; removing the separating agent charged with low molecular weight compounds from the extruder as the plasticized polymer passes through a low pressure zone having a residual pressure, P, which is lower the introductory pressure, P.sub.e, and for which 1 bar.gtoreq.P.gtoreq.P.sub.c ; collecting the charged separating agent as it is removed from the extruder; thermal vacuum treating the plasticized polymer as it passes through a last low pressure zone to vacuum degas the plasticized polymer at a pressure, P.sub.v, for which P.sub.v &lt;0.5 bar and thereby further remove separating agent and low molecular weight compounds from the plasticized polymer; and passing the plasticized polymer through a last high pressure zone to an extruder head. The combination of solvent extraction in the extruder with subsequent vacuum degassing results in removal of large amounts of low molecular weight compounds with a relatively small expenditure of energy since energy-intensive vacuum degassing is needed only for removal of residuals.

Process for separating low molecular weight compounds from an impure

A method and apparatus for the separation of viscous mixtures, comprising charging the mixture with solvent to form a dispersion before extraction to improve the extraction over a simple solvent extraction. The mixture to be treated is charged with solvent before the extraction and is then sprayed into the extraction column where it is dispersed. This treatment provides extraction of highly viscous, pasty materials. The charging with solvent can take place until the mixture is saturated with the solvent, and favorable temperature and pressure conditions for charging may be provided in a charging column that is separate from the extraction column.

Apparatus and method for the separation of a viscous mixture

A process for the continuous extraction of mixtures of organic substances including high boiling point constituents and/or constituents which do not boil but which melt with at least one solvent in the supercritical state, selected from the group consisting of CO.sub.2, propane, butane, pentane, petroleum ether, water, and having a critical temperature, T.sub.k, and a critical pressure, P.sub.k, the process including providing an extraction vessel which comprises an extraction column, the extraction column extending vertically, having a head portion at the upper end thereof and a sump portion at the lower end thereof, and having a temperature gradient which decreases with increasing height from the sump portion to the head portion, wherein the sump portion has a temperature effective to maintain extraction residue in a viscous state which permits continuous removal thereof from the sump portion, and wherein the head portion has a temperature effective to provide an optimum solution of the constituents to be extracted in the at least one solvent in the critical state; and extracting the mixture of organic substances with the at least one solvent in the supercritical state at a pressure, P, ranging from P&gt;P.sub.k up to P&lt;400 bar and at a temperature, T, of at least T&gt;T.sub.k to provide a charged fluid phase comprised of extracted substances.

Process for the continuous extraction of mixtures of organic substances

Process for separating solid substances from liquid mixtures of substances, wherein the liquid substances contained in the mixture are separated from the solid substances by countercurrent extraction with a solvent which, during the extraction process, is in a liquid or supercritical state and which, under standard conditions, is gaseous. The solvent is fed to a cylindrical extraction chamber at the lowest point of the extraction chamber. The solvent leaves the nozzles with a Reynold's number of 40,000 and flows upward in the extraction chamber with a Reynold's number of 2,700 to 8,000.

Process for separating a solid substance from a liquid mixture of

Apparatus for separating solid substances from liquid mixtures of substances, wherein the liquid substances contained in the mixture are separated from the solid substances by countercurrent extraction with a solvent which, during the extraction process, is in a liquid or supercritical state and which, under standard conditions, is gaseous. The solvent is fed to a cylindrical extraction chamber at the lowest point of the extraction chamber. The solvent leaves the nozzles with a Reynold's number of 40,000 and flows upward in the extraction chamber with a Reynold's number of 2,700 to 8,000.

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Essen, Germany

Klaus Reimann