Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: A purge system for a polymerization system may include a purge column including a stripping zone and a stripping fluid distributor below the stripping zone for injecting a stripping fluid including one or more light olefins. A first displacement zone is below the distributor. A second displacement zone is below the first displacement zone. A nitrogen distributor introduces nitrogen in the second displacement zone. Another purge system for a polymerization system may include a fluidized bed separator and a purge column. The fluidized bed separator includes a separator inlet, a stripping fluid inlet, a first stripped fluid outlet, and a separator outlet. The purge column includes a flake inlet, a stripping zone, a stripping fluid distributor below the stripping zone, a stripped flake outlet, and a second stripped fluid outlet for a second stripped fluid from the purge column.

Abstract: A gas-phase polymerization system and a solids recovery system for a fluidized bed reactor. The fluidized bed reactor can include a fluidizing gas outlet from which a discharged mixture of fluidizing gas and polymer fines is released, and a cyclone separator can separate the polymer fines from the fluidizing gas for reentry into the fluidized bed reactor. It has been found that by situating the reactor entry nozzle of the fines return line which is closest to the gas-phase reaction zone significantly higher in the reaction zone than in a conventional fines return line, and by directionally orientating the incoming stream of polymer fines and carrier gas into the fluidized bed in the reaction zone, a significant increase in the residence time of the particle in the reaction and larger particles which meet a product size distribution specifications are achieved.

Abstract: A purge system for a polymerization system may include a purge column including a stripping zone and a stripping fluid distributor below the stripping zone for injecting a stripping fluid including one or more light olefins. A first displacement zone is below the distributor. A second displacement zone is below the first displacement zone. A nitrogen distributor introduces nitrogen in the second displacement zone. Another purge system for a polymerization system may include a fluidized bed separator and a purge column. The fluidized bed separator includes a separator inlet, a stripping fluid inlet, a first stripped fluid outlet, and a separator outlet. The purge column includes a flake inlet, a stripping zone, a stripping fluid distributor below the stripping zone, a stripped flake outlet, and a second stripped fluid outlet for a second stripped fluid from the purge column.

Abstract: A technique of operating a gas phase fluidized bed polymerization reactor system may include feeding an olefin monomer and catalyst to a polymerization reactor. The monomer and the catalyst are contacted in a fluidized bed in the reactor to form a product including a polyolefin. A heat of polymerization is extracted from the reactor by recycling an inert condensable agent through the fluidized bed and condensing the inert condensable agent. The product is discharged from the reactor. The inert condensable agent includes propane, n-butane, or isobutane in a total mole fraction of greater than or equal to 0.50 of the inert condensable agent. A system including a gas phase fluidized bed polymerization reactor system may include a source of propane, n-butane, or isobutane for introduction into the polymerization system as an inert condensable agent. A loop slurry polymerization reactor system outlet may be the source of isobutane or propane.

Abstract: A downflow polymer product withdrawal system includes a withdrawal line to collect a product including a powder and a carrier gas. The line may include at least one downward sloped descending section and is absent of any non-self draining regions. The downflow system may further include a lock hopper, a fill valve between the line and the lock hopper, and a discharge valve downstream of the lock hopper. An upflow polymer product withdrawal system includes a withdrawal line to collect and discharge a product comprising a powder and a carrier gas. The line may include at least one non-vertical section including at least one upward sloped ascending section and at least one downward sloped descending section, and is absent of any non-self draining regions. The upflow system may further include a lock hopper, a fill valve between the line and the lock hopper, and a discharge valve.

Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: Techniques and systems for reducing fouling in a polymerization system are described. The polymerization system includes a reactor coupled to a recycle system. The recycle system includes at least one fouling-susceptible unit. The technique includes inducing polymerization of a reactant, for example, at least one olefin monomer reactant, with a catalyst in the reactor. The technique may further include circulating a fluidizing stream through the reactor and the at least one fouling-susceptible unit. The fluidizing stream may include entrained particles tending to foul the at least one fouling-susceptible unit. The technique can further include contacting the fluidizing stream with a catalyst poison at at least one location upstream of the at least one fouling-susceptible unit in the recycle system.

Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: A purge system for a polymerization system may include a purge column including a stripping zone and a stripping fluid distributor below the stripping zone for injecting a stripping fluid including one or more light olefins. A first displacement zone is below the distributor. A second displacement zone is below the first displacement zone. A nitrogen distributor introduces nitrogen in the second displacement zone. Another purge system for a polymerization system may include a fluidized bed separator and a purge column. The fluidized bed separator includes a separator inlet, a stripping fluid inlet, a first stripped fluid outlet, and a separator outlet. The purge column includes a flake inlet, a stripping zone, a stripping fluid distributor below the stripping zone, a stripped flake outlet, and a second stripped fluid outlet for a second stripped fluid from the purge column.

Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: Methods of reducing heat exchanger fouling rate or of producing polyolefins may include providing a first gas stream comprising a gas and entrained fine polyolefin particles to a gas outlet line; removing a portion of the entrained fine polyolefin particles from the gas outlet line to form a bypass stream; and providing the bypass stream to a bypass line comprising a bypass line inlet and a bypass line outlet. The bypass line inlet and outlet are located upstream and downstream of a first heat exchanger. The methods may further include providing at least a portion of the first gas stream to the first heat exchanger; and combining the bypass stream and a second gas stream at the bypass line outlet to form a combined gas stream comprising one or more olefins or paraffins. A temperature of the combined gas stream is below the dew point of the combined gas stream.

Abstract: Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Abstract: Techniques and systems for reducing fouling in a polymerization system are described. The polymerization system includes a reactor coupled to a recycle system. The recycle system includes at least one fouling-susceptible unit. The technique includes inducing polymerization of a reactant, for example, at least one olefin monomer reactant, with a catalyst in the reactor. The technique may further include circulating a fluidizing stream through the reactor and the at least one fouling-susceptible unit. The fluidizing stream may include entrained particles tending to foul the at least one fouling-susceptible unit. The technique can further include contacting the fluidizing stream with a catalyst poison at at least one location upstream of the at least one fouling-susceptible unit in the recycle system.

Abstract: The present invention discloses methods for removing volatile components from an ethylene polymer effluent stream from a polymerization reactor, and related polyethylene recovery and volatile removal systems. In these methods and systems, the polymer solids temperature is increased significantly prior to introduction of the polymer solids into a purge column for the final stripping of volatile components from the polymer solids.

Abstract: Systems and methods for improved degassing of polymer flake are provided herein. These systems include a polymerization reactor configured to polymerize one or more olefin monomers and produce a product stream comprising solid polymer flake entrained in a fluid; a flash chamber configured to separate the solid polymer flake from the fluid and to produce a fluid stream and a concentrated stream; and a first degassing chamber configured to separate the concentrated stream by contacting the concentrated stream with a purge fluid comprising one or more light hydrocarbons to produce a partially degassed polymer flake stream and a purge fluid stream.

Abstract: This disclosure provides for polymerization processes of polyolefins wherein the melt index can be regulated. For example, there is provided a process for producing a polyethylene, the process comprising: (1) in a polymerization reactor, contacting (a) a polymerization catalyst, (b) ethylene, (c) an optional ?-olefin comonomer, and (d) (x+y) ppm by weight of an antistatic agent on an ethylene basis; and (2) applying reaction conditions to the reaction mixture suitable to produce the polyethylene having a desired set of characteristics, such as desired target melt index. The disclosed polymerization processes allow for production of polyolefins having higher melt indices, and in the alternative to produce polyolefins having a desired target melt index at lower polymerization temperatures.