Abstract: The present invention relates to a process for the preparation of multimodal ethylene homo- or copolymers in at least two stages, the process comprising preparation of a first ethylene homo- or copolymer fraction in a loop reactor in slurry phase, preparation of a second ethylene homo- or copolymer fraction in a gas phase reactor, by using a catalyst not containing an inorganic oxide support, and operating the gas phase reactor in such conditions that at least part of the gas is recycled, and that at least a part of the recycled gas is condensed and the (partially) condensed gas is re-introduced into the gas phase reactor.

Abstract: Process and apparatus for continuously producing olefin polymers in a slurry phase reactor in a hydrocarbon diluent or liquid monomer. The process comprises continuously withdrawing from the slurry phase reactor a polymer slurry containing polymer and a fluid phase, which contains hydrocarbons and optionally hydrogen, and concentrating the slurry with a self-cleaning screen by removing a part of the fluid phase to provide a concentrated slurry. The openings of the screen, which can have a planar or cylindrical configuration, are smallest at the inflow surface of the screen and increases towards the outflow surface. By the present invention, the need for service and maintenance is significantly reduced.

Abstract: The present invention concerns a process and an apparatus for continuous polymerisation of olefin monomers. In particular, the present invention concerns a process and an apparatus for continuous polymerisation olefin monomers like ethylene and other monomers, wherein an olefin monomer is polymerised in slurry phase in an inert hydrocarbon diluent in at least one loop reactor. According to the invention, a polymer slurry is continuously withdrawn from the loop reactor and concentrated. The concentrated slurry is conducted to a flash unit in order to remove the remaining fluid phase, and gas obtained is compressed in a flash gas compressor before it is being fed to a distillation section. By means of the present invention it is possible reduce the size of the flash gas compressor and the capacity of the distillation sections. This significantly reduces investment cost for a continuously operated polymerization apparatus.

Abstract: The present invention relates to a process for the preparation of multimodal ethylene homo- or copolymers in at least two stages, the process comprising preparation of a first ethylene homo- or copolymer fraction in a loop reactor in slurry phase, preparation of a second ethylene homo- or copolymer fraction in a gas phase reactor, by using a catalyst not containing an inorganic oxide support, and operating the gas phase reactor in such conditions that at least part of the gas is recycled, and that at least a part of the recycled gas is condensed and the (partially) condensed gas is re-introduced into the gas phase reactor.

Abstract: The present invention concerns a process and an apparatus for continuous polymerisation of olefin monomers in a cascade of polymerisation reactors. According to the process, an olefin monomer is polymerised first in slurry phase in an inert hydrocarbon diluent in at least one loop reactor and then, subsequently, in gas phase in at least one gas phase reactor. According to the invention, a polymer slurry is continuously withdrawn from the loop reactor and optionally concentrated. The concentrated slurry is conducted to a high pressure flash unit in order to remove the remaining fluid phase, and fed to the gas phase reactor. With the process described in this invention, it is possible to produce bimodal polyethylene with good properties. The operation of the process is stable because of the truly continuous operation.

Abstract: A process for homo or copolymerizing propylene, wherein propylene is polymerized in the presence of a catalyst at an elevated temperature in a reaction medium in which a major part of the reaction medium is propylene and the polymerization is carried in at least one CSTR or loop reactor, where the polymerization is carried out at a temperature and a pressure which are above the corresponding critical temperature and the pressure of the reaction medium and were the residence time is at least 15 minutes. The process can also have a subcritical loop polymerization before the supercritical stage polymerization or gas phase polymerization after the supercritical stage polymerization.

Abstract: The present invention concerns a method and an apparatus of introducing polymer slurry obtained from a slurry reactor into a gas phase reactor containing a fluidized bed (C, D). According to the present invention, the content of the slurry reactor (R1) is conducted directly to the fluidized bed reactor (R2) as a multiphase stream comprising polymer, active catalyst and reaction medium using at least one feed line (10; 11; 12), and the stream is fed below a first fluidized zone (C) of the gas phase reactor via inlet pipe protruding into the fluidized bed in order to increase the once-through conversion of the process. By means of the invention, the amount of unreacted monomers which needs to be recirculated is minimized and investment and operation costs of the recovery section are greatly reduced.