Bayer Aktiengesellschaft

Clemens Casper

Johannes O Sajben

Gottfried Zaby

Dieter Grenner

Hugo Obermann

Jorgen Weinschenck

Claus H Wulff

Frank Wingler

Axel Lippert

Rudolf Binsack

Artur Reischl

Rainer Neumann

Steffen Kuhling

Christian Kords

Thomas Elsner

Hartmut Hetzel

J&uuml;rgen Heuser

Rolf Brockmann

Lothar Liebig

Klemens Kohlgr&uuml;ber

Walter Bockmann

Karl-August Lipper

Friedrich Bruhne

Peter Clasen

Gunter Lehr

Henning Klussmann

Edzard Tholema

Thomas Bamberger

Siegfried Zingel

Gunter Beilstein

Hans-Joachim Brockhaus

J&ouml;rgen Weinschenck

Karl-Heinz Jonen

Gerd-Rudiger Klette

Karl Morgenstern

Walter Damsky

A process of evaporating a viscous polymer solution is described. The process includes: (a) providing a viscous polymer solution including at least 30 wt. % of solvents and monomers; (b) introducing the viscous polymer solution into a heated helix ( ), the heated helix having a vapor exit velocity of 200 to 300 m/s, (a film flow including a two-phase mixture of polymer melt, and solvent vapors and monomer vapors being formed within the helix); (c) forwarding the film flow from helix ( ) into a heated vapor separator ( ); (d) expanding the two-phase mixture of polymer melt, and solvent vapors and monomer vapors of the film flow within vapor separator ( ) at an absolute pressure of 10 mbar to 800 mbar, (a bottom product including a concentrated melt of the polymer is formed within the vapor separator); and (e) withdrawing the bottom product from vapor separator ( ). Each of the helix ( ) and vapor separator ( ) have a separate heating device, and each of heating device independently provides a temperature that is above the softening point of the polymer.

Method for isolating polymers from solutions

In a method for improving heat transfer in a heat exchanger, in which a heating medium passes through heat exchange elements,which transfer their heat to a liquid with which they are in contact and which is located in the jacket region,of the heat exchanger, the liquid between the heat exchange elements in the jacket region,is heated locally to such a high temperature by means of additional heating elements,that nucleate boiling occurs in the liquid on the surface of these additional heating elements,and the resulting vapour bubbles ascend between the normal heating exchange elements,in the jacket region,. For this purpose an evaporative condenser containing vertically superimposed heat exchange elements,extending in a horizontal direction and a shell enclosing the jacket region,of the heat exchange elements,is provided, in which additional heating elements,connected to a heating medium circuit which is separate from the heat exchange elements,are arranged beneath the heat exchange elements,preferably in the bottom third of the vertical arrangement.

Method and an apparatus for improving heat transfer

This invention relates to a process for the production of polycarbonate agglomerate of high bulk density from polycarbonate solutions, in which the organic solvent is stripped from a solution of polycarbonate by means of steam, and which is characterised in that the resulting suspension of polycarbonate particles, condensed water and water- and solvent vapor is fed in a tube or tubular heat exchanger to a separator which is partially filled with water and which is under elevated pressure. The polycarbonate agglomerates are discharged, together with part of the water, via a pressure lock at the bottom of the separator.

Process for the production of polycarbonate agglomerate

The present invention provides a process for the isolation of partially crystalline polycarbonate powder or oligocarbonate powder from solutions thereof, in which process the organic solvent of a polycarbonate solution is vaporized in a heat exchanger, optionally with incorporation of steam, or in a holding tube with incorporation of steam and the pasty mixture of concentrated solution, solvent vapor and optionally water is separated in a separator. In this process, the solvent vapor is condensed in a heat exchanger downstream from the separator. The solvent is vaporized in the heat exchanger by indirect input of heat through the heat exchanger walls and vaporization may be promoted by preheating the polycarbonate or oligocarbonate solution in an upstream heat exchanger or by introducing steam or both.

Process for the isolation of partially crystalline polycarbonate powder

The viscosity of a fluid liquid substance is first increased in a multiphase coil in the presence of a gas phase flowing at high speed and then, with separation of the gas phase, the substance is applied to a stirred bed consisting of a solid granular material where it is converted into a solid substance.

Process and device for continuous evaporation to dryness of viscous

This invention relates to a process for producing granulated polymer materials from polymer solutions, in which organic solvent of the polymer solution is evaporated in a heat exchanger, optionally with the admixture of steam, or in a holding tube with the admixture of steam, and the paste-like mixture of concentrated solution, solvent vapour and optionally of condensed steam is separated in a separator provided with rotating built-in components for cleaning off the walls. The pre-concentrated polymer solution is further concentrated in the separator by supplying heat by way of heating the separator walls or the rotating built-in components and by the shearing energy of the rotating built-in components. Residual degassing of the solvent is effected before granulation, e.g. in the discharge extruder of the separator which is provided with rotating built-in components, through one or more degassing zones, optionally by the additional admixture of entraining media, such as inert gas or steam, for example.

Process for producing thermoplastic granulated polymer material from

In concentrating solutions containing 1 to 10% by weight of salts and resins, the yield and economics and trouble-free running can be improved by using a flow tube which has a steady curvature at least in the last third and is sized in its diameter in such a way that the mean flow velocity at the tube outlet is at least 50 m/second, and at least 90% by weight of the vaporizable components are evaporated off at driving temperature gradients of 20.degree. to 200.degree. C. between the heating medium and the solution.

Continuous process for concentrating solutions containing salts and

In concentrating polymer solutions up to a desired specification level of residual solvents, encrustations can be prevented and the yield and the degree of purity can be increased, when the product is heated up under pressure, expanded through a restrictor element (3) with vapor formation into a first, preferably coiled flow pipe (7) and concentrated therein as far as possible, the mixture of vapors and polymer solution is whirled at an angle into a second flow pipe (9) in a sloping arrangement and fitted with self-cleaning elements (11, 12) and concentrated therein up to the desired level, and vapors and concentrate are separately discharged only downstream thereof.

Continuous process for concentrating polymer solutions up to a required

In the thermal separation of solutions and suspensions into a free-flowing solid and into a largely solid-free distillate, the useful product can be almost completely recovered in a pure state, and the amount of waste product can thus be reduced, by carrying out the concentrating in a first heatable flow pipe (6) up to an upper limit which is given by a creeping coverage of the inside wall with solid and/or by a total blockage of the flow cross-section and then continuing the concentrating in a second flow pipe (9) which is made as a rotary pipe or as a paddle shaft apparatus and whose inside wall (12) is scraped continuously, and separating the vapors and solids from one another at the end of this flow pipe (9).

Continuous process for the separation of solutions and suspensions

The instant invention is directed to a process for stripping of a residual component from a liquid having a viscosity of from 300 to 10,000 poises in which the liquid flows in the form of a ring flow supported by a gas stream flowing in the core, through a tube into a separator vessel, the tube having a continuous coil shape and a conduit diameter to helix diameter of from 0.1:1 to 0.04:1, the improvement comprising adding to the gas stream from 10 to 90%, by weight, of externally generated steam and/or an inert gas at an adjusted pressure of from 50 m bars to 1 bar in the separator vessel for a gas and/or steam velocity in the tube of from 100 m/sec to the speed of sound. The added gas and/or steam generates thorough transverse mixing in the liquid ring flow.

Process for the removal of residual constituents

This invention relates to a process for carrying out reactions which primarily occur during the transport of compounds in the liquid phase or at the liquid-gas interface. Starting components are reacted with one another and/or with gases of the inner space in a multi-phase flow tube having a liquid ring flow which may contain dissolved and/or dispersed constituents. Any necessary heat exchange takes place between the liquid and the wall of the tube or the gases.

Process for carrying out reactions caused by the transport of substances

In a multiphase flow tube for drying pumpable suspensions to form solids having low residual moisture contents, the process uses brief increases in the pressure of the gas stream to prevent blockages.

Process for drying pumpable suspensions

Benzoyl chloride is prepared by a process in which the high-boiling residue obtained in the catalytic oxidation of toluene with oxygen or oxygen-containing gases in the liquid phase is largely freed of heavy metal salts which are present, and is then chlorinated at elevated temperatures, optionally under the action of light, and the benzoyl chloride is then separated off.

Process for the preparation of benzoyl chloride

This invention relates to a process for producing a homopolymer or co-polymer of an aromatic vinyl monomer by anionically polymerizing a monomer mixture in the absence of oxygen in a tubular coil evaporator.

Process for the anionic homo- or co-polymerization of aromatic vinyl

Viscous copper-containing catalyst waste is split up into solid particles and gaseous dichlorobutene along a steadily curved flow path, the liquid film flowing along an inner tube wall being driven along by the gas flowing at a higher rate in the core.

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Krefeld, Germany

Clemens Casper