Abstract: Tubular reactor for use in polymerization reactions having a design pressure PR of 40-65 barg. The reactor includes a tube with a wall, and at least a portion of the tube is oriented vertically, with at least part of the vertical portion being surrounded by a concentric jacket for the passage of cooling fluid. The design pressure in barg of the jacket PJ is less than 0.0018·PR2.25.

Abstract: Process for producing a polymer product in a slurry polymerization process, which slurry polymerization process includes a slurry heater for heating a stream of polymer product slurry withdrawn from a slurry reactor. The process includes reconfiguring the slurry heater from an initial slurry heater configuration to a subsequent slurry heater configuration and further where the slurry heater is reconfigured to form a subsequent slurry heater having a different total length and/or a different average internal diameter than the initial slurry heater.

Abstract: The present invention relates to slurry polymerisation, and in particular, to a slurry heater apparatus comprising at least two heating sections connected in fluid communication in series to form an initial slurry heater, wherein the slurry heater apparatus is adapted such that it can be reconfigured to form a subsequent slurry heater also comprising at least two heating sections connected in fluid communication in series, wherein the subsequent slurry heater has a different total length and/or a different average internal diameter than the initial slurry heater.

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: 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 removing heat from at least two reactors forming at least part of a polymerization reactor system for a multimodal polymerization in which the reactors are linked in series and all produce at least one component of the same polymer. The process includes cooling a stream of fluid in one or more heat exchangers and passing part of it to the cooling system of a first reactor and part of it to the cooling system of a second reactor, so as to remove the heat from said reactors, and passing back through the heat exchangers a return flow having a portion of the combined exit flows of the cooling fluids used to remove the heat from each of the reactors. The heat exchangers provide at least 90% of the cooling requirement for the reactors, and a portion of the combined exit flows from the reactors bypasses at least one of the heat exchangers and is passed directly to the cooling system of one or more of the reactors. The cooling circuit is powered by no more than one pump at any one time.

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 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 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: 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: Continuous process for manufacturing a polyolefin resin in at least two reactors in which in a first polymerization reactor, an olefin is polymerized continuously in the presence of a catalyst and a diluent to produce a first suspension comprising the diluent and polyolefin particles. At least a portion of the first suspension is transferred from the first polymerisation reactor to a second polymerisation reactor where further polymerisation takes place. A further suspension containing diluent and polymer particles is withdrawn from the second reactor and transferred to two separators, in each of which separators a diluent-rich flow and a concentrated suspension of polyolefin particles are formed and separated. The diluent-rich flow from one separator is recycled to a reactor preceding the second reactor, and the diluent-rich flow from the other separator is recycled to the second reactor. The invention enables higher separator efficiencies to be achieved.

Abstract: A process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device is described, comprising passing the stream through a heater comprising at least one transfer line for the stream and means for heating the transfer line, wherein the average particle size of the solid polymer is less than 3 mm, the mass flowrate of the polymer-containing stream exiting the heater is no more than 15% greater than the mass flowrate exiting the reactor, and the average velocity of the polymer-containing stream at 80% along the length of the heated part of the transfer line measured from the transfer line inlet is at least 6 m/s, preferably at least 8 m/s and more preferably at least 10 m/s and the pressure drop across the transfer line is between 0.01 bar/m and 0.2 bar/m.

Abstract: A continuous process for manufacturing a polyolefin resin in at least two reactors in series is described, in which: in a first polymerisation reactor, an olefin is polymerised continuously in the presence of a catalyst and a diluent to produce a first suspension comprising the diluent and polyolefin particles; at least a portion of said first suspension is transferred from the first polymerisation reactor to a second polymerisation reactor where further polymerisation takes place; a further suspension comprising diluent and polymer particles is withdrawn from the second reactor and transferred to two separators, in each of which separators a diluent-rich flow and a concentrated suspension of polyolefin particles are formed and separated, wherein the diluent-rich flow from one separator is recycled to a reactor preceding the second reactor, and the diluent-rich flow from the other separator is recycled to the second reactor. The invention enables higher separator efficiencies to be achieved.

Abstract: A process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, comprising passing the stream through at least two heaters operating in parallel, each heater comprising at least one transfer line for the stream and means for heating the transfer line, wherein 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: A tubular reactor for use in polymerisation reactions is described, having a design pressure PR of 40-65 barg, at least a portion of which is oriented vertically and at least part of which vertical portion is surrounded by a concentric jacket for the passage of cooling fluid, wherein the design pressure in barg of the jacket PJ is less than 0.0018.PR2.25. Another aspect of the invention concerns a tubular reactor for use in polymerisation reactions having a design pressure PR of 40-65 barg, at least a portion of which is oriented vertically and at least part of which vertical portion is surrounded by a concentric jacket for the passage of cooling fluid, wherein the actual thickness of the reactor wall is either no more than 2 mm greater and/or no more than 10% greater than the minimum wall thickness required to withstand the design pressure PR as calculated according to the ASME Boiler and Pressure Vessel code.

Abstract: A cooling circuit for at least two reactors which form at least part of a polymerisation reactor system is described, which circuit comprises: one or more heat exchangers which provide at least 95% of the cooling requirement for the cooling circuit; a cold flow of cooling fluid exiting the one or more heat exchangers, part of which cold flow passes into a first inlet flow directed to the cooling system of a first reactor, and part of which passes into a second inlet flow directed to the cooling system of a second reactor; a return flow comprising the combined exit flows of the cooling fluids used to remove the heat from each of the reactors; wherein a potion of the return flow is diverted to bypass at least one of the heat exchangers, and is wholly or partly incorporated into at least one of the first and second inlet flows. The application also covers a process using the above circuit.

Abstract: Apparatus for activating a catalyst is described, comprising means for passing high-temperature gases across a catalyst, a primary filter for filtering said gases, means for cooling the filtered gases, and a secondary filter for filtering the cooled gases which collects at least 99.97% of all residual particles smaller than 0.3 ?m, wherein the secondary filter is disposable and/or has a design pressure less than 0.5 bar.

Abstract: 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%.

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, 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.