Description: Coverage of production capacity in Europe: 76%
Types:
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text_type: Report,
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Comment: The dataset represents the production mix of commercial PP production technologies: slurry suspension polymerisation,Bulk suspension polymerisation, gas phase polymerisation using Ziegler-Natta and Metallocene catalysts PP is usually manufactured with the gas phase or the suspension (slurry) process. Modern suspension processes, however, use liquid monomers instead of a solvent and are termed “bulk” process. In the gas phase processes a fluidised bed of polymer particles and catalyst is maintained by a steady gaseous monomer feed from the bottom of the reactor. Polymer powder is continuously extracted at the bottom of the fluidised bed reactor. Unreacted monomer gas from the top is compressed and recycled to the reactor inlet. Catalyst, and co-catalyst if necessary, is also continuously fed to the reactor. Typically Ziegler-Natta catalysts are used for gas phase polymerisation where the catalyst is supported on inert silica particles so that the reaction takes place at the catalyst surface. The suspension polymerisation can be described as precipitation process. The formation of the polymer takes place in a hydrocarbon diluent and under conditions, where the monomer is soluble in the solution. The precipitated polymer, however, is insoluble and forms a fine suspension. The polymer is then separated by centrifugation. The suspension process can be combined with a stirred tank reactor or a loop reactor. Different diluents can be chosen, like C5 to C9 hydrocarbons, hexane, or isobutane. The bulk suspension process describes the slurry suspension process used for the production of PP where the monomer propylene is used as solvent instead of other hydrocarbons. Modern suspension processes for the production of PP use liquid monomers instead of gaseous. After the reaction phase, most of the residual (unreacted) monomers (which are mostly present as gases) are separated from the polymer and are either recycled back into the process or flared of. Depending on the purity of the separated monomers, the gas can either be fed directly back into the production line or the monomers are returned to a purification unit. To limit the accumulation of impurities in the process, usually a small side-stream (purge) of the unreacted gas is sent back to the cracker or to a dedicated purification unit. After polymerisation, the polymer is usually fed di-rectly into a hot melt extruder, where additives can be added to the melted polymer if required. The polymer is then pelletised in an underwater pelletiser. The pelletised product is dried, blended where required and degassed.
Origin: /Bund/UBA/ProBas
Tags: Polypropylen ? Granulat ? Europa ? Manufacture of basic chemicals, fertilizers and nitrogen compounds, plastics and synthetic rubber in primary forms ? Manufacture of chemicals and chemical products ? Manufacture of plastics and synthetic rubber in primary forms ? Manufacturing ?
License: unbekannt
Language: Deutsch
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