Abstract: A process for starting a multizone circulating reactor containing no polyolefin particles, comprising the steps of conveying gas through the reactor and the gas recycle line, feeding a particulate material comprising a polymerization catalyst and optionally polyolefin into the reactor, controlling the gas flow in a vertical reactor zone equipped with a throttling valve at the bottom so that the upwards gas velocity in the bottom part of this reaction zone is lower than the terminal free-fall velocity of the particulate material fed into the reactor, and, after the weight of the particulate polyolefin in this reactor zone is higher than the drag force of the upward moving gas, controlling the circulation rate of the polymer particles within the multizone circulating reactor by adjusting the opening of the throttling valve and adjusting the flow rate of a dosing gas.

Abstract: A process for continuously preparing a polyolefin composition made from or containing a polyolefin and carbon black in an extruder device. The process includes the steps of supplying polyolefin in form of a polyolefin powder and carbon black to a mixing device; alternatively, (a) measuring the flow rate of the polyolefin powder supplied to the mixing device or (b) measuring the flow rate of the polyolefin pellets prepared in the extruder device; adjusting the flow rate of the carbon black to the mixing device in response to the measured flow rate of the polyolefin powder or adjusting the flow rate of the polyolefin powder to the mixing device in response to the measured flow rate of the polyolefin pellets; melting and homogenizing the mixture within the extruder device; and pelletizing the polyolefin composition into the polyolefin pellets.

Abstract: A method for preparing a dried powder is provided. The facility includes a first drying chamber having a heating element and a second drying chamber. A mixture of powder and diluent is introduced into the first drying chamber. A pre-dried powder is transferred from the first drying chamber into the second drying chamber. A dried powder, including a recirculated amount of powder and a discharge amount of powder, is formed in the second drying chamber. The recirculated amount of the dried powder is transferred by a conveyor device from the second drying chamber into the first drying chamber. The discharge amount of the dried powder is discharged from the second drying chamber.

Abstract: A process for polymerizing ethylene to obtain an ethylene-based polymer in a plant, wherein the plant includes a reactor in fluid communication with a recycle connection, wherein the process includes a polymerization phase, a partial shutdown phase, and the steps of reducing the pressure in the reactor for entering into the partial shutdown phase from the polymerization phase; and increasing the pressure in the reactor for exiting from the partial shutdown phase and re-entering the polymerization phase.

Abstract: A process for continuously preparing a polyolefin composition made from or containing a bimodal or multimodal polyolefin and one or more additives in an extruder device equipped with at least one hopper. The process includes the steps of supplying a bimodal or multimodal polyolefin in form of a polyolefin powder to the hopper; (a) measuring the flow rate of the polyolefin powder or (b) measuring the flow rate of the prepared polyolefin pellets; supplying one or more additives to the hopper; adjusting the flow rates of the additives supplied to the hopper in response to the measured flow rate of the polyolefin powder or adjusting the flow rate of the polyolefin powder in response to the measured flow rate of the polyolefin pellets; melting and homogenizing the polyolefin powder and additives within the extruder device; and pelletizing the molten polyolefin composition into the polyolefin pellets.

Abstract: A polyethylene composition having the following features: 1) density from about 0.945 to about 0.951 g/cm3, determined according to ISO 1183 at 23° C.; 2) ratio MIF/MIP from about 25 to about 43; 3) MIF from about 3.5 to less than about 8.5 g/10 min.; 4) HMWcopo index from about 1 to about 40; and 5) long-chain branching index, LCBI, equal to or greater than about 0.83. The polyethylene composition can be used to produce pipes.

Abstract: A process for preparing an ethylene polymer including the step of homopolymerizing ethylene or copolymerizing ethylene with one or more comonomers in a gas-phase polymerization reactor including a riser unit wherein growing polymer particles flow upwards under fluidization, fast fluidization or transport conditions and a downcomer wherein growing polymer particles flow downward in a densified form, wherein the hold-up of polymer particles in the downcomer is from 55 wt. % to 80 wt. % of the total hold-up of polymer particles in the gas-phase polymerization reactor.

Abstract: Process for preparing an olefin polymer including the step of polymerizing an olefin in the presence of a polymerization catalyst and hydrogen as molecular weight regulator in a gas-phase polymerization reactor to yield growing polymer particles, the reactor including three or more polymerization zones and at least two thereof are sub-zones of a polymerization unit wherein the growing polymer particles flow downward in a densified form and at least one polymerization zone has a ratio of hydrogen to the sum of olefins which is a factor of at least 1.5 lower than the ratio of hydrogen to the sum of olefins in the polymerization zone having the highest ratio of hydrogen to the sum of olefins and a factor of at least 1.5 higher than the ratio of hydrogen to the sum of olefins in the polymerization zone having the lowest ratio of hydrogen to the sum of olefins.

Abstract: A method of controlling the polymer composition of an ethylene copolymer in a process for preparing ethylene copolymers by copolymerizing ethylene and at least one other olefin in the presence of a polymerization catalyst system comprising at least one late transition metal catalyst component (A), at least one Ziegler catalyst component (B), and at least one activating compound (C) by adding an alkyl alkoxy silane or a dialkyl ether for increasing the relative portion of the ethylene copolymer component obtained from polymerization by late transition metal catalyst component (A), or by adding a saturated halogenated hydrocarbon for increasing the relative portion of the ethylene copolymer component obtained from polymerization by Ziegler catalyst component (B), processes for copolymerizing ethylene and at least one other olefin in the presence of such a polymerization catalyst system comprising utilizing the controlling method, a method for altering the polymer composition of an ethylene copolymer obtai

Abstract: The present disclosure provides a low density polyethylene (LDPE) having (A) a density from 0.910 to 0.924 g/cm3, determined according to ISO 1183 at 23° C.; (B) an elongational hardening of at least 4.2, at 150° C. at an elongational rate of 1 s?1; (C) a ratio Mw/Mn of at least 18, where (i) Mw is the weight average molar mass, measured by a MALLS detector coupled to a GPC, and (ii) Mn is the number average molar mass, measured by GPC (Gel Permeation Chromatography); and (D) a Mw of at least 230,000 g/mol. The present disclosure also provides an article of manufacture made from or containing (A) a substrate and (B) a coating layer made from or containing the disclosed LDPE. The present disclosure further provides a polymerization process occurring (A) in the presence of oxygen as the only radical initiating agent and (B) in the absence of solvents.

Abstract: A process for polymerizing or copolymerizing ethylenically unsaturated monomers at pressures in the range of from 110 MPa to 500 MPa in a production line comprising a continuously operated polymerization reactor, wherein at least one of a pre-heater or pre-cooler, a polymerization reactor or a post reactor cooler is composed of tubes of a length from 5 m to 25 m which are flanged together, either directly or via bends, and the flanges are covered by a chimney construction, and wherein air is conveyed through the chimney construction and the air exiting the chimney construction is monitored with respect to the hydrocarbons concentration.

Abstract: The present disclosure relates to a continuous process for the preparation of ethylene homopolymers or ethylene copolymers comprising polymerizing ethylene or copolymerizing ethylene and one or more other olefins in the presence of a chromium catalyst in a gas-phase polymerization reactor which is equipped with a cycle gas line for withdrawing reactor gas from the reactor, leading the reactor gas through a heat-exchanger for cooling and feeding the reactor gas back to the reactor, wherein the polymerization is carried out at a temperature from 30° C. to 130° C. and a pressure of from 0.1 to 10 MPa and an aliphatic carboxylic acid ester having from 8 to 24 carbon atoms is added.

Abstract: The present disclosure relates to a manufacturing plant for high-pressure polymerization having a layered tubular reactor and a method for an emergency shutdown in said manufacturing plant. The present disclosure also relates to a process for manufacturing LDPE using said layered tubular reactor.

Abstract: The present disclosure relates to a manufacturing plant for high-pressure polymerization having a layered tubular reactor and a method for an emergency shutdown in said manufacturing plant. The present disclosure also relates to a process for manufacturing LDPE using said layered tubular reactor.

Abstract: A process for polymerizing or copolymerizing ethylenically unsaturated monomers at pressures in the range of from 110 MPa to 500 MPa in a production line comprising a continuously operated polymerization reactor, wherein at least one of a pre-heater or pre-cooler, a polymerization reactor or a post reactor cooler is composed of tubes of a length from 5 m to 25 m which are flanged together, either directly or via bends, and the flanges are covered by a chimney construction, and wherein air is conveyed through the chimney construction and the air exiting the chimney construction is monitored with respect to the hydrocarbons concentration.

Abstract: A process for polymerizing or copolymerizing ethylenically unsaturated monomers at pressures in the range of from 110 MPa to 500 MPa in a production line comprising a continuously operated polymerization reactor which is installed within a protective enclosure, wherein the production line is monitored with respect to an occurrence of a leakage of monomers or of reaction mixture and a water based deluge system, which provides droplets of a diameter in a range from 25 ?m to 20 mm to the enclosed area, is automatically started with a minimum flow rate of 10 L/min per m2 of enclosed area when a leakage of monomers or of reaction mixture is detected.

Abstract: The present disclosure relates to a plant for performing polymerization, such as the polymerization of ethylene, having a recycle connection with two or more cooling channels arranged in parallel, a process for polymerization and downstream processes, and a plant for polymerization, comprising the following plant components in fluid communication: a) A reactor with an inlet side and an outlet side; b) A recycle connection positioned in fluid communication between the outlet side of the reactor and the inlet side of the reactor; wherein the recycle connection comprises two or more cooling channels arranged in parallel.

Abstract: A method for feeding an antistatic compound to a polymerization reactor comprising the steps of: a) dispersing, under mixing conditions, a catalyst powder and an antistatic compound in an oil, so as to form a suspension of catalyst powder and antistatic compound in said oil; b) successively adding, under mixing conditions, a molten thickening agent to said suspension from step a), while maintaining said suspension at a temperature such that said thickening agent solidifies on contact with said suspension; c) transferring the product obtained from b) to a polymerization reactor.

Abstract: A process for polymerizing or copolymerizing ethylenically unsaturated monomers at pressures in the range of from 110 MPa to 500 MPa in a production line comprising a continuously operated polymerization reactor, wherein the process comprises monitoring the surrounding of the production line with respect to an occurrence of a leakage of monomers or of reaction mixture by an IR point detector arrangement of at least three groups of IR point detectors which are capable of detecting hydrocarbons and the groups of IR point detectors are operating according to a voting logic and starting automatically an emergency pressure release program when a group of IR point detectors of the IR point detector arrangement detects the presence of hydrocarbons.

Abstract: Polyethylene composition for injection molding with a beneficial balance of environmental stress cracking resistance and impact resistance in combination with low warpage and beneficial processing behavior, said composition having the following features: 1) density of 0.945 g/cm3 or higher; 2) MIE from 1 to 30 g/10 min.; 3) ratio MIF/MIE from 15 to 30; 4) ER values from 0.40 to 0.52.