Mitsui Petrochemical Industries, Ltd.

Mitsui Chemicals, Inc.

Ube Industries, Inc.

Mitsui Engineering and Shipbuilding Company Limited

Ryoichi Yamamoto

Akifumi Kato

Satoru Ohtani

Yoshiaki Kikuchi

Hiroshi Suzuki

Mitsunori Ichimura

Teruhisa Kojima

Junichi Yoshida

Yoshinori Morita

Kenji Doi

Shigemi Shiraki

Tomohiro Arase

Hiroshi Nishikawa

Shotaro Matsuda

Shikiho Itaya

Haruyuki Koda

Toshiyuki Sakata

Etsuro Okamoto

Toshihiro Okano

Hideo Mineshima

Hiroshi Kudo

Kiyoshi Kuioka

Katsutoshi Horimoto

Nobuhiko Kaneshige

Yasuaki Ishida

Yasuhiko Yagi

Koji Inaba

Toyoma Hoshino

Takao Uetake

Toshimi Hachimori

Takahiro Mamyoda

Fujimasa Nakao

Etsurou Okamoto

A method of treating polyolefin comprises (i) a ligand-decomposition step of contacting polyolefin, which is obtained by the use of a transition metal compound containing ligands having cyclopentadienyl skeleton, with a ligand decomposer, such as water, oxygen, alcohol, alkylene oxide or peroxide, to decompose the ligands contained in the polyolefin, and (ii) a ligand-removal step of heating the polyolefin contacted with the ligand decomposer to remove the decomposed ligands from the polyolefin. According to this method, the residual ligands having cyclopentadienyl skeleton, which are contained in the polyolefin produced by the use of a transition metal compound containing ligands having cyclopentadienyl skeleton, are decomposed and removed from the polyolefin, whereby polyolefin diminished in odor development in the molding process can be obtained.

Method of treating polyolefin

A method for vapor phase polymerization comprises blowing a gaseous monomer from a bottom of a fluidized bed reactor through a distributor plate into the reactor by means of a blower while feeding a solid catalyst into the reactor to thereby form a fluidized bed in the reactor and conducting a vapor phase polymerization to produce a polymer or copolymer, wherein the blower has a slide or rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side in a blower body casing, said slide or rotational slide part being provided with a noncontacted gas leakproof seal part at a clearance ranging from 0.7 to 2.5 mm.

Method of vapor phase polymerization, vapor phase polymerizer and blower

Drying of a solid polymer is disclosed in which a solid polymer obtained by polymerization (or a product of modification of the solid polymer) is contacted with a drying gas so that any solvent and/or unreacted polymerization feed materials remaining in the solid polymer are removed to thereby dry the solid polymer, and in which a gaseous polymerization feed material is used as the drying gas and contacted with the solid polymer to thereby dry the solid polymer (step i), and the resultant solid polymer is contacted with a drying gas which contains an inert gas (step ii). The drying gas can be recovered from the step (i) and part thereof can be recycled through a polymerization step as it is or be recycled, after cooling the drying gas to thereby remove any condensed components, to the step (i). Not only can the solid polymer be efficiently dried but also the solvent and unreacted polymerization feed materials recovered from the solid polymer can efficiently be recycled by the disclosed method.

Drying solid polymer apparatus

A gas distributor plate provided in a fluidized bed polymerization vessel which effects the gas phase polymerization of olefins, the gas distributor plate exhibiting excellent action for uniformly diffusing the gas flow in the fluidized bed zone. A gas distributor plate has a number of gas passage holes and is provided in a fluidized bed polymerization vessel which effects the gas phase polymerization of olefins, wherein when the inner radius of the straight drum portion of the polymerization vessel is denoted by 1, the holes perforated in the outer peripheral portion of the distributor plate at 0.7 to 1.0 from the center of the straight drum portion have an average diameter which is larger than the average diameter of the holes perforated in the inner peripheral portion of the distributor plate at smaller than 0.7 from said center. This makes it possible to uniformly and stably diffuse the gas flow in the fluidized bed zone in the polymerization vessel, to effectively prevent the formation of a dead zone, as well as to effectively prevent the polymer from adhering onto the wall surfaces of the polymerization vessel.

Gas distributor plate for a gas phase polymerization apparatus

A rotor 22 accommodated in a casing 26 has a circumferential surface sliding on the internal surface of the casing 26 in airtight condition. The casing 26 is provided with a powder feed part 27 positioned above the rotor and is provided with a powder drop part 30 positioned under the rotor. At least one quantity-measuring recessed part is formed in the slide surface of the rotor. In accordance with the rotation of the rotor, the quantity-measuring recessed part comes to communicate with the powder feed part, so that powder is fed from the powder feed part into the quantity-measuring recessed part. When the rotation is advanced, the quantity-measuring recessed part comes to communicate with the powder drop part, so that the powder drops from the quantity-measuring recessed part through the powder drop part into a high-pressure part 19 arranged thereunder. These members construct a quantitative powder feeder which, even when a pressure difference exists between the supply side and the supplied side, can effectively prevent the gas flow and pressure leak therebetween and can minimize the amount of carrier gas used for feeding powder.

Quantitative powder feeder capable of feeding powder by fixed amounts

A method for recovering crystals from a crystal-containing slurry, which comprises supplying the slurry to a rotary filter having a rotating cylindrical filter medium, filtering the supplied slurry in a filtering region to retain the crystals on the filter medium and washing the filter cake formed on the rotating filter medium repeatedly in a plurality of washing regions by spraying a washing liquid onto the cake in each region by supplying any one of washing regions on the aft side in the rotating direction of the filter medium with the spent washing liquid of the washing region adjacent to said one washing region on the fore side in the rotating direction.

Method for recovering crystals from slurry with wash water recycle means

A process and an apparatus for producing terephthalic acid economically by oxidizing paraxylene supplied to an oxidizing reactor connected with a compactly designed distillation column in an acetic acid-based solvent, while effecting the distillatory recovery of the paraxylene and acetic acid efficiently without suffering from stuffing of the distillation column.

Process and apparatus for producing terephthalic acid

A process for exchanging a dispersing medium of a terephthalic acid slurry by introducing an aliphatic carboxylic acid slurry of terephthalic acid into a multi-stage column at the upper part thereof and introducing water at the lower part thereof to form an upflowing stream of water in the multi-stage column, while a sedimentation of terephthalic acid particles is effected, and withdrawing an aqueous aliphatic carboxylic acid solution from the upper part of the multi-stage column and an aqueous slurry of terephthalic acid from the lower part of the multi-stage column.

Process for exchanging dispersing medium of terephthalic acid slurry

Mud is taken into a vertical screw conveyor while an inlet device is rotating or without the use of such an inlet device. The mud is sent from the discharge port of the conveyor into a transport pipe. The mud is forcibly sent by a compressed air. Screens are provided to take only the mud into the screw conveyor. Paddles for stirring mud are provided on the vanes of the screw. A check valve and/or a pressure feeder (transport pump) is provided between the discharge port of the conveyor and the transport pipe.

Dredging apparatus

In a process for producing an olefin polymer which comprises continuously polymerizing an olefin in the presence of a catalyst composed of a transition metal compound component and an organometallic compound component in at least two independent polymerization zones connected in series by a pipeline while feeding the olefin and the catalyst into an upstream zone of polymerization and withdrawing the resulting polymer from a downstream zone of polymerization; the improvement wherein

Process for continuous multi-stage polymerization of olefins

A process for producing an ethylene copolymer which comprises polymerizing a predominant amount of ethylene and a minor amount of an alpha-olefin having 4 to 10 carbon atoms in the gaseous phase in the presence of a catalyst composed of (A) a transition metal catalyst component and (B) an organometallic compound of a metal of Groups I to III of the periodic table; characterized in that the copolymerization is carried out under the following conditions (i) and (ii),

Process for producing ethylene copolymer by gaseous phase

A fluid bed reactor system for olefin polymerization composed of a cylindrical reaction vessel equipped with a distribution plate and an agitator, characterized in that the distribution plate satisfies the following conditions,

Fluid bed reactor system composed of cylindrical reaction vessel

A process for polymerizing an olefin in the gaseous phase in a multiplicity of steps in at least two independent polymerization zones connected to each other by a transfer passage, which comprises feeding an olefin and a catalyst into a first polymerization zone, polymerizing the olefin in the gaseous phase, intermittently or continuously withdrawing a gaseous stream containing the resulting polymer from the first zone and feeding it into said transfer passage, introducing the withdrawn polymer-containing gaseous stream into a second polymerization zone through the transfer passage, feeding the or an olefin into the second zone with or without feeding an additional supply of the catalyst thereinto, and polymerizing the olefin in the gaseous phase in the second zone; characterized in that an inert gas zone is provided in the transfer passage, and at least a part of the gas components of the gaseous stream containing the polymer is replaced by an inert gas.

Process for multi-step gaseous phase polymerization of olefins

An improved anchor agitator is provided for performing uniform and effective stirring of the fluidized bed zone of a polymerization vessel in a gaseous phase polymerization, especially of olefins such as ethylene and propylene. The anchor agitator includes at least two pairs of arms provided on a rotating shaft in mutually crossing positions. A pair of main blades is provided at opposite outward end portions of one pair of arms and at the opposite outward portions of each remaining pair of arms a pair of subsidiary blades is provided. The main blades and subsidiary blades extend substantially parallel along the axis of the rotating shaft and each pair of blades is located substantially equidistant from the axis of the rotating shaft. The pair of main blades is located farther from the axis of the rotating shaft than the subsidiary blades. The main blades and subsidiary blades are uniquely designed to avoid the formation of coherent crusts or lumps near the inner wall of the polymerization vessel and to avoid formation of a vortex formed centrally in the fluidized bed zone of the vessel in the vertical direction of the zone. The unique angular relationships and distance relationships of the main blades and subsidiary blades also avoid the likelihood of vibration due to mechanical imbalance of the agitator while at the same time allowing the agitator to be easily designed and built.

Anchor agitator for gaseous phase polymerization vessel

In a process for polymerizing olefins in the gaseous phase in a first gas-phase polymerization zone and a second gas-phase polymerization zone, which are provided independently from each other, in the presence of a catalyst composed of a transition metal catalyst component and an organometallic compound of a metal of Groups I to III of the periodic table and in the co-presence of hydrogen gas while feeding the catalyst-containing polymer formed in the first zone to the second zone; the improvement wherein (i) a dilution zone for diluting a feed flow from the first gas-phase polymerization zone which comprises a mixture of the polymer, the catalyst, the olefin gas and hydrogen gas by feeding a fresh supply of olefin gas thereto is provided in a feed passage for feeding said flow from the first gas-phase polymerization zone to the second gas-phase polymerization zone, (ii) a part of the gas phase in said feed flow diluted in the dilution zone is recycled to the first gas-phase polymerization zone, and remainder is fed into the second gas-phase polymerization zone, and (iii) in the second gas-phase polymerization zone, the hydrogen to olefin mole ratio is maintained lower than that in the first gas-phase polymerization zone.

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Yamaguchi, Japan

Ryoichi Yamamoto