Basf Aktiengesellschaft

Basell Polyolefine Gmbh

Harth & Seifert Gmbh

Farid Rizk

Andreas Deckers

Kaspar Evertz

Peter Hennenberger

Franz Zahradnik

Klaus Borho

Heinz Vogt

Klaus Hilligardt

Horst Bullack

Benno Knauer

Alfred F Hauss

Michael Witt

Manfred Liebscher

Klaus J Tischendorf

Roland Schafer

The invention relates to a method and an apparatus for the polymerization of gaseous olefins, in particular of ethylene and at least one &agr;-olefin, in the gas phase in a stirred or fluidized, catalyst-containing polymerization zone ( ) and at least one decompression zone ( ) downstream of the polymerization zone ( ). The mixture of solid (co)polymer and unreacted monomers leaving the polymerization zone ( ) flows through a settling zone, in particular in the form of a settling leg ( ), before the decompression zone.

Gas phase polymerization method

Ethylene/.alpha.-olefin copolymers are prepared by catalytic dry-phase copolymerization of the monomers in a stirred or fluidized polymerization zone, transfer of the resulting mixture of solid copolymer and unconverted gaseous monomer into a let-down zone and separation of the mixture, after pressure reduction, into a gaseous phase and a solid phase, by a continuous process in which the solid phase is continuously flushed beforehand with gaseous ethylene and then flushed with a mixture of nitrogen and steam. The ethylene copolymers are very substantially free of residual monomers and odor and flavor substances.

Low pressure copolymerization of ethylene with .alpha.-olefins and

Polyamide granules are dried and heated by feeding a suspension of granules in water into a sieve (1), where the bulk of the water is removed, and then into a tower dryer (10), where they are deposited in bed form and then freed of the remaining water while moving in plug flow under the force of gravity with a counter-current inert gas stream at from 70.degree. to 200.degree. C. The tower dryer possesses an inlet at the top (11) and outlet at the bottom (34) for the granules and also feed lines (20, 22, 31) for the inert gas. To achieve a uniform degree of drying of the granules, the inert gas is divided on entry into the tower dryer at a point between the drying zone and the heating zone into a stream which flows radially inward into the bed of granules on the one hand and a stream which flows radially inward and outward on the other. In this way the inert gas is distributed particularly uniformly and the granules are dryable in a very short drying zone down to a water content of 0.0001 kg of water/kg of polymer. The lower, conically tapered area of the tower dryer--bin 30--ensures a uniform rate of descent of the granules and hence a uniform solid-phase condensation with a favorable molecular weight distribution. The tower dryer (10) is followed by a fluidized bed cooler (41) in which the granules are cooled with air to &lt;50.degree. C.

Drying and heating of polyamide granules

The instant invention relates to a process for the blending of bulk materials by means of a jet gas blender, whereby the blending porcess is initiated only when full gas pressure is reached and when the valve immediately upstream of the storage tank (3) has been closed. At the end of the set time period 't.sub.1 ' the valve (4) leading to the blending container (6) is closed in effect simultaneously and the valve (4.1) leading to the storage tank (3) is reopened, whereby the blended material settles in the blending container (6) without being disturbed by turbulence in this control position and whereby this phase is maintained for a set period of time. Only at the end of that period of time is the line cross-section leading to the filter (8) opened to allow exhaust air to go through, and its passage is thereby adjusted so that the quantity of exhaust air going through the filter remains approximately constant per time unit. When the pressure in the blending container (6) has dropped to the level of the atmospheric pressure the material is discharged via the discharge opening.

Process for mixing bulk materials

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Neuhofen, Germany

Farid Rizk