Abstract:
A method and apparatus for taking a sample from a flowing suspension formed by polymer particles and hydrocarbon diluent in a olefin polymerization process including at least one filter situated at a plane of an inside surface of a transfer conduit between reactors. Each filter includes perforations or pores having a size to prevent substantially any of the catalyst used in the polymerization process from passing through the filter, e.g., smaller than the smallest particle size of a catalyst used in the polymerization process. The pore or perforation size of each filter is preferably 0.1-10 .mu.m, preferably between 0.2-1 .mu.m. A pressure difference permits at least partial vaporization of the sample as it passes through the filter.
Abstract:
Reactor assembly for the production of polymers including a fluidized bed reactor (1) comprising a bottom zone (5), a middle zone (6) and an upper zone (7), an inlet (8) for the fluidization gas located in the bottom zone (5), an outlet (9) for the fluidization gas located in the upper zone (7); the outlet (9) for the fluidization gas being coupled with the fluidized bed reactor (1) via inlet (8) via a gas circulation line; means for separation of solids from gas (2) being connected to said gas circulation line; the equivalent cross-sectional diameter of the upper zone (7) being monotonically decreasing with respect to the flow direction of the fluidization gas through the fluidized bed reactor; the middle zone (6) having an essentially constant equivalent cross-sectional diameter with respect to the flow direction of the fluidization gas through the fluidized bed reactor; the equivalent cross-sectional diameter of the bottom zone (5) being monotonically increasing with respect to the flow direction of the fluidization gas through the fluidized bed reactor; characterized in that the ratio of the height of the fluidized bed reactor to the equivalent cross-sectional diameter of the middle zone of the fluidized bed reactor is from 2 to 10; and whereby said upper zone (7) is directly connected to said middle zone (6).
Abstract:
The present invention deals with a process of producing a polymer of at least one olefin in two consecutive reactors in gas phase in the presence of an olefin polymerization catalyst where an olefin is polymerized in a first polymerization reactor in the presence of an olefin polymerization catalyst and a first reaction gas mixture to form a fluidized bed comprising an olefin polymer and said first reaction gas mixture.
Abstract:
The present invention deals with a process of producing a polymer of at least one olefin in two consecutive reactors in gas phase in the presence of an olefin polymerisation catalyst where an olefin is polymerised in a first polymerization reactor in the presence of an olefin polymerisation catalyst and a first reaction gas mixture to form a fluidized bed comprising an olefin polymer and said first reaction gas mixture. The first reaction gas mixture together with the olefin polymer is continuously or intermittently withdrawn from the first polymerisation reactor and directed into a separation vessel so that a bed of polymer is formed in said separation vessel. A portion of said first reaction gas mixture is withdrawn from said separation vessel and returned into the first polymerization reactor to a point where the pressure is lower than in the separation vessel. The olefin polymer is withdrawn from said separation vessel to form a second product stream and the second product stream is directed into a second polymerization reactor. A second gas may be introduced into the bottom part of the separation vessel to avoid the carry-over of the reactants from the first polymerisation stage into the second polymerisation stage.
Abstract:
The invention concerns a method and an equipment for taking a sample in slurry polymerization. The sample is taken directly from the liquid phase of the reactor (15) through an in-line filter (40). The slurry flow is maintained in the in-line filter (40) at a sufficiently hight level to prevent immobilization of polymer or catalyst particles on the filter face of the in-line filte (40).
Abstract:
A method is provided for controlling the dosage of a fluidized polymerizing catalyst into a polymerization reactor. The method comprises mixing a solid polymerization catalyst with wax and feeding the flowing catalyst-wax mixture through a pipe to the dosage pump. The inlet opening of the cylinder of the dosage pump is opened to draw catalyst-wax mixture through the inlet opening by means of the back motion of the piston. The inlet opening is then closed and the outlet opening is opened. Flowing catalyst-wax mixture is then pressed from the cylinder through the outlet opening by means of the back motion of the piston. The outlet opening is then closed. Opening and closing of the inlet and outlet openings is carried out by rotating an intermediate pipe arranged between the cylinder and piston so that a transmission opening in the intermediate pipe moves upon either the inlet or outlet opening. The intermediate pipe surface always covers at least one of the inlet or outlet openings.
Abstract:
The invention is directed to a process for the treatment of plastic material comprising a) providing a liquid; b) contacting the plastic material with the liquid; c) keeping the plastic material in the liquid at Tb−25° C. to Tb of the liquid, wherein Tb is the boiling point of the liquid at the applied pressure; and d) removing the plastic material from the liquid. Furthermore, the invention is directed to the use of a liquid for the treatment of plastic material and to a plant for treating plastic material with a liquid.
Abstract:
A method and an apparatus of discharging polymer from a continuously operated gas phase reactor, wherein at least one monomer is polymerized in a bed containing active catalyst formed by catalyst and polymer particles suspended in a fluid, the bed defining a fluidized bed level in said reactor. The invention includes continuously withdrawing polymer powder from the reactor; and adjusting the discharge rate of the polymer powder so as to maintain a constant bed level during polymerization. By means of the invention the discharge of the polymer can be made truly continuous without any disturbance of the polymerization. The rate of withdrawn polymer can be flexibly adjusted depending on the progress of the polymerization and it can also easily be scaled up if the capacity of the reactor is increased.
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.