Continuous gas fluidized bed polymerization process

A reaction system for the preparation of a polyolefin from one or more α-olefin monomers of which at least one is ethylene or propylene,

• wherein the reaction system comprises:
• a reactor,
• a product purge bin,
• a granular feed bin downstream of the product purge bin,
• a recovery unit, and
• an extrusion unit directly coupled to the granular feed bin,
• wherein the reactor comprises a fluidized bed, an expanded section located at or near the top of the reactor, a distribution plate located at the lower part of the reactor and an inlet for a recycle stream located under the distribution plate,
• wherein the system is arranged such that
• a) a polymerization catalyst is fed to the fluidized bed in the area above the distribution plate,
• b) the one or more α-olefin monomers is fed to the reactor,
• c) fluids are circulated from the top of the reactor to the bottom of the reactor, wherein the circulating fluids are cooled using a heat exchanger, resulting in a cooled recycle stream comprising liquid, and wherein the cooled recycle stream is introduced into the reactor using the inlet for the recycle stream,
• d) a stream comprising the polyolefin and fluids is withdrawn from the reactor and said stream is passed into the product purge bin,
• e) the product purge bin is purged with a purge stream comprising a first inert gas and steam such that a stream comprising a purged polyolefin and a stream comprising fluids are obtained, wherein the stream comprising the fluids, which is a stream obtained directly from the product purge bin, is substantially free of steam,
• f) at least part of the stream comprising the fluids is introduced back into the reactor via the recovery unit,
• g) the stream comprising the purged polyolefin is introduced into the granular feed bin and
• h) contacting a deactivating stream comprising steam with the purged polyolefin in the granular feed bin to obtain a polyolefin that is substantially free of active polymerization catalyst.

A process for the preparation of a polyolefin in a reaction system from one or more α-olefin monomers of which at least one is ethylene or propylene,

• wherein the reaction system comprises
• a reactor,
• a product purge bin,
• a granular feed bin located downstream of the product purge bin,
• a recovery unit, and
• an extrusion unit directly coupled to the granular feed bin,
• wherein the reactor comprises a fluidized bed, an expanded section located at or near the top of the reactor, a distribution plate located at the lower part of the reactor, and an inlet for a recycle stream located under the distribution plate,
• wherein the process comprises:
• a) feeding a polymerization catalyst to the fluidized bed in the area above the distribution plate,
• b) feeding the one or more α-olefin monomers to the reactor,
• c) circulating fluids from the top of the reactor to the bottom of the reactor, wherein the circulating fluids are cooled using a heat exchanger, resulting in a cooled recycle stream comprising liquid, and wherein the cooled recycle stream is introduced into the reactor using the inlet for the recycle stream,
• d) withdrawing a stream comprising the polyolefin and fluids from the reactor and passing said stream into the product purge bin,
• e) purging the product purge bin with a purge stream comprising a first inert gas and steam such that a stream comprising a purged polyolefin and a stream comprising fluids are obtained, wherein the stream comprising the fluids is substantially free of steam,
• f) introducing at least part of the stream comprising the fluids back into the reactor via the recovery unit,
• g) introducing the stream comprising the purged polyolefin into the granular feed bin, and
• h) contacting a deactivating stream comprising steam with the purged polyolefin in the granular feed bin to obtain a polyolefin that is substantially free of active polymerization catalyst, wherein the stream comprising the purged polyolefin is introduced directly into the granular feed bin.