Abstract: A gas-phase polymerization reactor for the gas-phase polymerization of olefins including a polymerization zone having a recycle line for (a) withdrawing reaction gas from the reactor, (b) leading the reaction gas through a heat-exchanger for cooling, and (c) feeding the reaction gas back to the reactor, wherein the recycle line has the heat-exchanger, a centrifugal compressor having variable guide vanes, and a butterfly valve, and a related process for preparing an olefin polymer in the gas-phase polymerization reactor.

Abstract: A nano platelet gibbsite treated with compound of formula (ORa)3Si—R or of formula Rc—COOH wherein Ra equal to or different from each other is a C1-C10 alkyl radical; Rb is a C5-C30 hydrocarbon radical and Rc is a C5-C30 hydrocarbon radical is used as a catalyst support.

Abstract: A gas-phase polymerization reactor for the gas-phase polymerization of olefins including a polymerization zone having a recycle line for (a) withdrawing reaction gas from the reactor, (b) leading the reaction gas through a heat-exchanger for cooling, and (c) feeding the reaction gas back to the reactor, wherein the recycle line has the heat-exchanger, a centrifugal compressor having variable guide vanes, and a butterfly valve, and a related process for preparing an olefin polymer in the gas-phase polymerization reactor.

Abstract: A process for preparing a multimodal ethylene copolymer in suspension in a reactor cascade including a first polymerization reactor and subsequent polymerization reactor(s) including polymerizing ethylene and C3-C12-1-alkenes and forming a suspension of multimodal ethylene copolymer particles in a suspension medium made from or containing a diluent, transferring the suspension into a separator, wherein the suspension is separated into multimodal ethylene copolymer particles and recovered suspension medium, purifying part of the recovered suspension medium for producing purified components of the recovered suspension medium, and recycling part of the purified components of the recovered suspension medium to the first polymerization reactor of the reactor cascade, wherein the purified components of the recovered suspension medium recycled to the first polymerization reactor and made from or containing the diluent, undergo catalytic hydrogenation before being introduced into the first polymerization reactor.

Abstract: Method for the preparation of dried polymer pellets in a facility having a dryer with a first chamber and a mechanical agitator, and the facility further having a degassing silo with a second chamber, the method includes the steps of guiding a drying gas flow made from or containing a first gas mixture for drying wet polymer pellets into the first chamber, transferring the dried polymer pellets into the second chamber, guiding a second gas mixture for degassing the dried polymer pellets into the second chamber thereby transforming the second gas mixture into a third gas mixture and guiding a portion of the third gas mixture into the first chamber; and process for manufacturing LDPE pellets.

Abstract: A slurry polymerization process for the preparation of polyethylene in a reactor cascade of two or more polymerization reactors wherein monomers are polymerized in the polymerization reactors which include a reactor outlet arranged in each reactor bottom for feeding a reactor slurry to a subsequent polymerization reactor and for emptying the polymerization reactor.

Abstract: A process for preparing an olefin polymer, including the steps of forming a particulate olefin polymer in a gas-phase polymerization reactor in the presence of a C3-C5 alkane as polymerization diluent, separating discharged polyolefin particles from concomitantly discharged gas at a pressure from 1 to 2.2 MPa, degassing the polyolefin particles at a pressure from 0.1 to 0.4 MPa with a gas made from or containing a C3-C5 alkane; and transferring the separated gas and the gas from the degassing to a work-up unit operated at a pressure from 0.001 to 0.2 MPa below the pressure of the separation, wherein the gas for degassing is continuously received from the work-up unit.

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 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: A polyethylene composition for producing blow-molded hollow articles, having the following features: 1) density from 0.948 to 0.952 g/cm3 determined according to ISO 1183-1 at 23° C.; 2) ratio MIF/MIP from 12 to 25; 3) MIF from 18 to 40 g/10 min.; 4) Mz equal to or greater than 1,200,000 g/mol; 5) ?0.02 from 35,000 to 55,000 Pa·s; 6) long-chain branching index, LCBI, equal to or greater than 0.55; and 7) ratio (?0.02/1000)/LCBI from 55 to 75.

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 process for the preparation of ethylene homopolymers or copolymers in a facility having a high-pressure tubular reactor and a preheater, wherein a reaction fluid introduced into the reactor at a reactor inlet is heated in the preheater and the average velocity of the reaction fluid in the preheater is lower than the average velocity of the reaction fluid in the tubular reactor and the ratio of the average velocity in the tubular reactor to the average velocity of the reaction fluid in the preheater is in the range from 1.5 to 5.

Abstract: A polyethylene composition for producing blow-molded hollow articles, having the following features: 1) density from 0.940 to 0.955 g/cm3, determined according to ISO 1183 at 23° C.; 2) ratio MIF/MIP from 12 to 40; 3) Mz from 500,000 to 3,500,000 g/mol; 4) ?0.02 from 80,000 to 300,000 Pa·s; 5) HMWcopo index from 1 to 15; and 6) Mz/Mw*LCBI lower than 6.4.

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 method for aligning a cutter plate in a pelletizer for polymer pellets using a remote alignment adjustment device having a mechanical distance measurement probe and a camera for taking photos or videos. The remote alignment adjustment device is attached to the drive shaft of the cutter plate and rotates with the shaft to correct the alignment in different positions of the die plate. Additionally, a process for preparing polyethylene pellets in a pelletizer using the method for aligning the cutter plate.

Abstract: Fluidized-bed reactor for the gas-phase polymerization of olefins including a gas distribution grid installed in a lower part of the fluidized-bed reactor and a gas recycle line, which is equipped with a compressor and a heat exchanger and which is connected at the upper end with the top of the fluidized-bed reactor, wherein the gas recycle line splits at the lower end in at least two horizontal branches which are connected tangentially with the fluidized-bed reactor below the gas distribution grid and a process for preparing an olefin polymer carried out in the fluidized-bed reactor.

Abstract: A method for cleaning a metal surface of a metal component of an industrial plant is disclosed comprising measuring the electrical resistance RA1 of a metal component over a cleaned area of the metal surface with a resistance meter, comparing the electrical resistance RA1 measured with a pre-determined electrical resistance value RDET, assessing whether RA1 is greater, smaller or equal to RDET, and repeating cleaning if the electrical resistance RA1 measured is greater than RDET, or terminating cleaning of the surface area of the metal component if RA1 is smaller than or identical to RDET.

Abstract: A process for preparing a polyolefin composition including the steps of supplying a bimodal or multimodal polyolefin in form of a polyolefin powder having an mass-median-diameter D50 in the range from 300 ?m to 2500 ?m and one or more additives to a mixing device, mixing the polyolefin powder and the additives at a temperature from 10° C. to 120° C., transferring the mixture into a extruder device, melting and homogenizing the mixture within the extruder device to form a molten polyolefin composition, and pelletizing the molten polyolefin composition.

Abstract: Monomodal copolymers of ethylene and molding compositions comprising such copolymers, wherein the copolymers have a density determined according to DIN EN ISO 1183-1, variant A in the range from 0.938 to 0.944 g/cm3, a melt index MFR21 determined according to ISO 1133 at 190° C. under a load of 21.6 kg in the range from 12 to 17 g/10 min, a weight average molar mass Mw in the range from 140 000 g/mol to 330 000 g/mol, a polydispersity Mw/Mn in the range from 9 to 17, and a content of comonomer side chains per 1000 carbon atoms Cx equal to or above a value defined via equation (I) Cx=128.7?134.62×d?, wherein d? is the numerical value of the density of the copolymer in g/cm3, the use of the copolymers for producing injection-molded articles, as well as injection-molded articles comprising the copolymers, and process for the preparation of such monomodal copolymers.

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.