Patent application number | Description | Published |
20100174037 | SLURRY PHASE POLYMERISATION PROCESS - A polymerisation process is disclosed in which polyethylene is produced in slurry in a polymerisation reactor in the presence of a Ziegler Natta catalyst and an activator, and slurry containing the polymer is withdrawn from the reactor and transferred to a flash tank operating at a pressure and temperature such that at least 50 mol % of the liquid component of the slurry is withdrawn from the flash tank as a vapour and at least 98 mol %, more preferably at least 98.5 mol %, and most preferably at least 99.5 mol %, of the vapour withdrawn from the flash tank is capable of being condensed at a temperature of between 15 and 40C without compression, wherein a by-product suppressor, which reduces the amount of by-product formed per unit of polyethylene produced by at least 10% compared with an identical polymerisation process where the by-product suppressor is not present, is used in the reactor. | 07-08-2010 |
20100190921 | SLURRY PHASE POLYMERISATION PROCESS - Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a first polymer is made in suspension in a first reactor and 80-20 wt % of a second polymer is made in suspension in a second reactor in the presence of the first polymer, and a stream or slurry containing the resulting polymer is withdrawn from the second reactor and transferred to a flash tank operating at a pressure and temperature such that at least 50 mol % of the liquid component of the slurry, or the non-polymer component of the stream entering the flash tank, is withdrawn from the flash tank as a vapour, wherein the concentration in the stream or slurry entering the flash tank of components having a molecular weight below 50 g/mol, C | 07-29-2010 |
20100210796 | SLURRY PHASE POLYMERISATION PROCESS - Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a high molecular weight (HMW) polymer is made in suspension in a first reactor and 20-80 wt % of a low molecular weight (LMW) polymer is made in suspension in a second reactor in the presence of the HMW polymer, wherein the solids concentration in the second LMW reactor, defined as the mass of polymer divided by the total mass of slurry, is at least 35 wt %, most preferably between 45 wt % and 60 wt %, and/or the ratio of solids concentration in the first reactor to that in the second reactor is maintained at less than 1.0, preferably between 0.6 and 0.8, and further wherein the volume of the second reactor is at least 10%, preferably at least 30% and more preferably at least 50% greater than the volume of the first reactor. | 08-19-2010 |
20100249344 | SLURRY PHASE POLYMERISATION PROCESS - Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a high molecular weight (HMW) polymer is made in suspension in a first reactor and 20-80 wt % of a low molecular weight (LMW) polymer is made in suspension in a second reactor, wherein the ratio of the average activity in the LMW reactor to the average activity in the HMW reactor is from 0.25 and 1.5, where average activity in each reactor is defined as the rate of polyethylene produced in the reactor (kgPE/hr)/[ethylene concentration in the reactor (mol %)×residence time in the reactor (hours)×feed rate of catalyst into the reactor (g/hr)], residence time being defined as the mass of the polymer in the reactor (kg)/the output rate of polymer from the reactor (kg/hr), and wherein the volume of the second reactor is at least 10%, preferably at least 30% and more preferably at least 50% greater than the volume of the first reactor, and the ratio of length to diameter of the first reactor, L/D(1), is greater than that of the second reactor, U/D(2), and preferably at least 20% greater. | 09-30-2010 |
20100273960 | SLURRY PHASE POLYMERISATION PROCESS - Process for producing a multimodal polyethylene in at least two loop reactors connected in series, in which 20-80 wt % of a high molecular weight (HMW) polymer is made in suspension in a first reactor and 20-80 wt % of a low molecular weight (LMW) polymer is made in suspension in a second reactor, one polymer being made in the presence of the other in either order, wherein the ratio of the average activity in the LMW reactor to the average activity in the HMW reactor is from 0.25 and 1.5, where average activity in each reactor is defined as the rate of polyethylene produced in the reactor (kgPE/hr)/[ethylene concentration in the reactor (mol %)×residence time in the reactor (hours)×feed rate of catalyst into the reactor (g/hr)], residence time being defined as the mass of the polymer in the reactor (kg)/the output rate of polymer from the reactor (kg/hr), and the volumes of the two reactors differ by less than 10%. | 10-28-2010 |
20120289665 | NOVEL POLYMERS - Copolymers of ethylene and α-olefins are provided having (a) a density (D) in the range 0.900-0.940 g/cm3, (b) a melt index MI | 11-15-2012 |
20130109812 | POLYETHYLENE COMPOSITION | 05-02-2013 |
20140142260 | SLURRY PHASE POLYMERISATION PROCESS - A slurry process for the polymerisation of ethylene is disclosed, which takes place in a reactor system comprising one or more reactors in series, having a characteristic such that the average polymerisation productivity [kg PE/kgcata] per unit ethylene per hour aI during operation at any first residence time rI is less than 1.7 (a2r2 −aIrI)/(r2−rI), where a2 is the average polymerisation productivity [kgPE/kgcata] per unit ethylene per hour during operation at any second residence time r2 where r2>rI, a2 and r2 being measured either in the same reactor in the case of a single reactor polymerisation, or in a reactor subsequent to the reactor in which aI and rI are measured in the case where the polymerisation takes place in more than one reactor, and wherein the specific yield of the reactor system is greater than 0.3 tonnes/m | 05-22-2014 |
20150080541 | CATALYST FOR THE POLYMERISATION OF OLEFINS, PROCESS FOR ITS PRODUCTION AND USE - The present invention provides a new process for preparing a catalyst for the gas phase polymerization of olefins wherein the sequence of addition of the catalyst components and the selection of the said components provides a catalyst composition which exhibits a superior response to hydrogen, a surprisingly high productivity and an improved activity profile. The catalyst consists of compounds of a group IV transition metal, Mg, C1 and A1 supported on a silica support. | 03-19-2015 |