Abstract: The present invention relates to a polymerisation process, in particular to the polymerisation of olefins in a reactor system comprising two reactors in series, and most particularly provides a process for the polymerisation of monomer in at least first and second reactors operated in series, which process comprises contacting a first stream comprising vapour derived from the effluent withdrawn from the second reactor with a feed stream to the second reactor, said feed stream comprising effluent derived from the first reactor.

Abstract: Process for polymerizing in a loop reactor an olefin monomer optionally together with an olefin comonomer in the presence of a polymerization catalyst in a diluent to produce a slurry including solid particulate olefin polymer and the diluent. The Froude number is in the range 3 to 10, the internal diameter of the loop reactor is over 600 millimeters, the solids concentration of the slurry in the loop reactor is above 20% by volume and, when the polymer produced is polyethylene and the diluent is an alkane, the solids concentration is above 40 wt % based on the total weight of the slurry.

Abstract: A process comprising polymerising in a loop reactor an olefin monomer optionally together with an olefin commoner in the presence of a polymerisation catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number is maintained at or below 20 is disclosed.

Abstract: 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.

Abstract: Polymerization process in a slurry loop reactor having a slurry loop reaction zone with a volume of at least 50 m3 and an internal diameter (D) of 50 cm or greater, a feed inlet for monomers and diluent, a catalyst inlet for polymerisation catalyst, and a discharge conduit for removal of polymer. Monomer, diluent and catalyst are passed into the reaction zone through their respective inlets where they form a slurry of polymer solids having a polymer solids concentration in the reaction zone of greater than 20 wt %. The space-time yield (STY) is greater than 100 kg/h/m3, and the catalyst inlet is an inlet pipe such that no part of the inlet pipe protrudes beyond the wall of the reaction zone and into the reaction zone by more than 1/10th of the diameter of the reaction zone at the point where the inlet pipe joins the reaction zone.

Abstract: A process comprising polymerizing in a loop reactor an olefin monomer optionally together with an olefin commoner in the presence of a polymerization catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number is maintained at or below 20 is disclosed.

Abstract: The present invention relates to a process for maintaining a continuous gas-phase (co-) polymerisation of olefins in a large fluidised bed reactor in a homogeneous mode whilst operating at high space time yield and condensation rate in the presence of a polymerisation catalyst.

Abstract: Process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, by passing the stream through at least two heaters operating in parallel, each heater having at least one transfer line for the stream and a heater for heating the transfer line. The average particle of the polymer is below 3 mm, the temperature of the polymer-containing stream at the outlet of all heaters is maintained above the dew point of the stream, and no heater has a volumetric flowrate of polymer-containing stream more than three times that of any other heater.

Abstract: The present invention relates to a reactor, and in particular to a slurry loop polymerisation reactor which comprises: a) a reaction zone in the form of a slurry loop, b) at least one feed inlet for monomers, comonomers and diluent, c) at least one catalyst inlet for polymerisation catalyst, and d) at least one discharge conduit for removal of polymer, characterised in that the at least one catalyst inlet is in the form of an inlet pipe and no part of the inlet pipe protrudes beyond the wall of the reaction zone and into the reaction zone by more than 1/10th of the diameter of the reaction zone at the point where the inlet pipe joins the reaction zone.

Abstract: Process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, by passing the stream through a heater having at least one transfer line for the stream and a heater for heating the transfer line. The average particle size of the solid polymer is less than 3mm, the mass flowrate of the polymer-containing stream exiting the heater is no more than 15% greater than the mass flowrate exiting the reactor, the average velocity of the polymer-containing stream either at a point 80% along the length of the heated part of the transfer line measured from the transfer line inlet, or at the transfer line outlet, is at least 6 m/s, and the pressure drop across the transfer line per unit length is between 0.0125 bar/m and 0.1 bar/m.

Abstract: Process for polymerising, in a loop reactor, at least one olefin monomer in a liquid diluent to produce a slurry comprising solid particulate olefin polymer and said diluent, wherein the ratio between the actual volumetric solids concentration of the slurry and the maximum possible geometric volume solids concentration of the slurry as measured by the bulk density of an unpacked settled bed of particles, SVCR, is V*0.065 or greater, and the ratio of the cumulative settling distance of an average size particle at any point in the reactor in any direction perpendicular to the direction of the flow, to the internal diameter of the loop reactor, is maintained below [0.084*(V?6.62)+(0.69?SVCR)* 1.666], where V is the circulation velocity of the slurry in m/s and “cumulative settling distance” is defined as the cumulative distance, expressed as a fraction of the diameter, travelled by a particle in any direction perpendicular to the direction of the flow since the previous upstream pump.

Abstract: Process for producing a degassed polymer powder, by a) feeding i) a principal monomer, and ii) one or more comonomers in an amount of at least 5000 ppmw relative to the principal monomer feed rate, and iii) optionally an added alkane having 2 to 10 carbon atoms, fed in an amount of at least 1000 ppmw relative to the principal monomer feed rate; into a polymerization reactor. The monomer and comonomers react to form a polymer including residual hydrocarbons having one or more hydrocarbons with 3 to 10 carbon atoms, and b) passing the polymer to a degassing step where it is contacted with a purge gas to remove some of the residual hydrocarbons.

Abstract: Process for polymerising, in a loop reactor, at least one olefin monomer in a liquid diluent to produce a slurry comprising solid particulate olefin polymer and said diluent, wherein the ratio between the actual volumetric solids concentration of the slurry and the maximum possible geometric volume solids concentration of the slurry as measured by the bulk density of an unpacked settled bed of particles, SVCR, is V*0.065 or greater, and the ratio of the cumulative settling distance of an average size particle at any point in the reactor in any direction perpendicular to the direction of the flow, to the internal diameter of the loop reactor, is maintained below [0.084*(V?6.62)+(0.69?SVCR)* 1.666], where V is the circulation velocity of the slurry in m/s and “cumulative settling distance” is defined as the cumulative distance, expressed as a fraction of the diameter, travelled by a particle in any direction perpendicular to the direction of the flow since the previous upstream pump.

Abstract: 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, Clights (mol %), satisfies the equation Clights<7+0.07(40?Tc)+4.4(Pc?0.8)?7(CH2/CEt) where Tc and Pc are respectively the temperature (in ° C.

Abstract: Process for producing a multimodal polyethylene in at least two loop reactors connected in series. In the process 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. 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%.

Abstract: 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.

Abstract: 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. 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). The volume of the second reactor is at least 10% 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, L/D(2).

Abstract: Polymerisation process in which polyethylene is produced in slurry in a polymerisation reactor in the presence of a Ziegler Natta catalyst and an activator, and a stream or 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 or non-polymer component of the stream entering the flash tank or slurry is withdrawn from the flash tank as a vapour and at least 98 mol % of the vapour withdrawn from the flash tank is capable of being condensed at a temperature of between 15 and 50° C., without compression. 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. The molar ratio of the by-product suppressor added to the reactor to titanium added to the reactor is between 0.2 and 1.

Abstract: A process comprising polymerising in a loop reactor of continuous tubular construction an olefin monomer optionally together with an olefin comonomer in the presence of a polymerisation catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the internal diameter of at least 50% of the total length of the reactor is at least 700 millimeters and the solids concentration in the reactor is at least 20 volume % is disclosed.

Abstract: Process comprising polymerizing in a loop reactor of a continuous tubular construction an olefin monomer optionally together with an olefin comonomer in the presence of a polymerization catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent, wherein the average internal diameter of at least 50% of the total length of the continuous tubular loop reactor is at least 700 mm wherein the HMW polymer is produced in a reactor upstream of the LMW polymer reactor and the ratio of the average internal diameter of the HMW reactor to the average internal diameter of the LMW reactor is between 0.8 and 1.4.