Abstract:
The invention relates to a strand evaporator comprising a degassing vessel (6), a product entry (11), a product distributor (17), a product discharge (13), and a vapor discharge (12). The invention is characterized in that the product distributor (17) is configured as a manifold distributor that is provided with at least one distributing pipe (1) and with a multitude of parallelly arranged nozzle pipes (2), which have a multitude of openings (15) in the pipe wall. The invention is also characterized in that the nozzle tubes (2) are preferably arranged one above the other in a number of planes and such that they are laterally offset.
Abstract:
Disclosed is a process for devolatilizing a polymer comprising the polymer through a devolatizer comprising a plate heat exchanger wherein the plate heat exchanger are heated by a plurality of heating tubes and wherein the heating tube comprises a return tube nested inside of a supply tube. The use of the disclosed invention allows for a comparatively small heat profile across heating plates as compared to prior art plate heat exchangers.
Abstract:
A method and an apparatus for removing residual monomers from a slurry containing polyvinyl chloride while preventing degradation of polyvinyl chloride and the drop of its quality. The apparatus comprises a cylindrical column main body (46), a plurality of porous plates (32 to 38) disposed in a vertical direction inside the column main body, a plurality of chambers defined on the porous plates by using these porous plates as their bottom surfaces, slurry introduction portions (19 to 24) provided to at least two of these chambers, flow-down portions (13 to 18) disposed between the porous plates so as to allow the slurry to sequentially flow down from the porous plates of the upper chambers to the porous plates of the lower chambers, a steam inlet (10) disposed at the bottom of the column main body, a vent (11) disposed at the top of the column main body, a slurry discharge port (12) disposed in a chamber below a chamber having a slurry inlet, and hot water injection means (25 to 31) disposed immediately below the porous plates in such a manner as to face at least the lower surfaces of the porous plates, wherein a slurry introduction pipe (48) is connected to the slurry inlet (50) through an on/off valve (49) and the inner diameter of the slurry introduction pipe (48) is progressively expanded towards the slurry inlet (50) up to at least 1.2 times.
Abstract:
The present invention provides an apparatus (100) and method of reducing volatiles in a mass processable polymer. The apparatus comprises a multi-chambered devolatilizer (160) having first and second collectors (220, 225) contained therein. In one embodiment, the invention provides a method that includes passing the mass processable polymer stream from a polymerization process to a first devolatilizer (130). The method continues by passing the polymer stream from the first devolatilizer to the multi-chambered devolatilizer. The apparatus and method allows for the production of a polymer having less than 100 ppm of volatiles.
Abstract:
The invention relates to the evaporation of a viscous polymer solution having at least 30 wt.%, preferably at least 50 to 70 wt.%, solvents and monomers. According to the inventive method, the polymer solution to be evaporated is guided through a heated helical tube (5) as a film flow with a vapor exit velocity ranging from 200 to 300 m/s and flows into a heated separator (6) afterwards. Heating of the helical tube (5) and of the separator (6) is realized in such a way that the temperatures of the heating means in the helical tube (5) and in the separator (6) are above the softening point of the polymer. An additional important method criterion is characterized in that the two-phase mixture which is made of a polymer melt, solvent vapors, and monomer vapors and which is formed in the helical tube (5) is relieved to a pressure ranging from 10 mb to 800 mbabs in the heated vapor separator (6).
Abstract:
Disclosed is a process for devolatilizing a polymer comprising the polymer through a devolatizer comprising a plate heat exchanger wherein the plate heat exchanger are heated by a plurality of heating tubes and wherein the heating tube comprises a return tube nested inside of a supply tube. The use of the disclosed invention allows for a comparatively small heat profile across heating plates as compared to prior art plate heat exchangers.
Abstract:
The invention relates to a device for carrying out material exchange processes for high-viscosity liquids, especially for evaporating and/or degasifying polymer melts. The inventive device consists of at least one vertical container (1) having a supply line (4) for the liquid to be treated, an outlet (7) for volatile constituents and an outlet (6) for the treated liquid. Said supply line (4) is provided with a distribution element (3) having a plurality of openings (8, 10) for distributing the high-viscosity liquid to be treated between a plurality of individual currents. Said distribution element is characterised in that essentially vertically arranged wire loops (2) are arranged near the openings (8, 10). The high-viscosity liquid flows over said wire loops under the effect of gravity.
Abstract:
An improved polymer devolatilization apparatus comprising a flat plate heater (22) comprising a polymer solution supply means (20), and a liquid/vapor collection and separation means, said flat plate heater further comprising a multiplicity of flat plates defining a plurality of channels (10), each channel having a substantially uniform height, but varying width over the total channel length, each channel comprising three zones: a first zone (12), having a beginning (18) and a terminus, said beginning in operative communication with the polymer solution supply means, characterized by decreasing width as a function of distance from its beginning, a second zone (14) having a beginning at the terminus of the first zone and a terminus, characterized by at least one occurrence of a restrictive cross-sectional area, and a third zone (16) having a beginning at the terminus of the second zone and terminating at a liquid/vapor collection and separation region operating at reduced pressure, said third zone characterized by increasing width as a function of distance from its beginning, and provided further that the ratio of maximum width of the third zone to the maximum width of the second zone is from 2:1 to 20:1.
Abstract:
A highly energy efficient process for removing hydrocarbons from polymer slurries is disclosed. The process includes feeding a hydrocarbon-containing polymer slurry to a flash tank to flash a portion of the hydrocarbon from the slurry. Thereafter, the resulting slurry is fed to a fluid bed dryer wherein additional hydrocarbon is stripped from the polymer. Subsequently, the resulting polymer powder is transferred to a powder silo wherein further hydrocarbon is removed from the polymer utilizing a heated purge gas flowing countercurrent to the polymer powder. The polymer output preferably has a low hydrocarbon content, on the order of 100 ppm or less.
Abstract:
The present invention provides an apparatus and method of reducing volatiles in a mass processable polymer. The apparatus comprises a multi-chambered devolatilizer having first and second collectors contained therein. In one embodiment, the invention provides a method that includes passing the mass processable polymer stream from a polymerization process to a first devolatilizer. The method continues by passing the polymer stream from the first devolatilizer to the multi-chambered devolatilizer. The apparatus and method allows for the production of a polymer having less than 100 ppm of volatiles.