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 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 providing a flow of particulate matter to a reactor, by intermittently adding the particulate matter and a diluent to a mixing tank, and continuously withdrawing a slurry of particulate matter in diluent from the mixing tank for introduction into the reactor. Prior to each addition of particulate matter and diluent to the mixing tank, the concentration of particulate matter in the diluent already in the mixing tank is measured or calculated, and the amount of particulate matter and diluent subsequently added is measured so as to achieve the same concentration at the end of the addition as that measured or calculated prior to the addition.

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: 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: 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: 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: A process for the separation of volatile material from particulate polymer discharged from a polymerisation reactor in the form of a polymer slurry and which has been substantially freed from unreacted monomer in an earlier separation step, comprising (a) feeding the particulate polymer to a purge vessel and causing it to move through the vessel in substantially plug-flow mode, (b) heating the particulate polymer in the purge vessel to a temperature greater than 30° C.

Abstract: A process for the separation of volatile material from particulate polymer which has been substantially freed from unreacted monomer in an earlier separation step, comprising (a) feeding the particulate polymer to a purge vessel, optionally causing it to move through the vessel in substantially plug-flow mode, (b) heating the particulate polymer in the purge vessel to a temperature grater than 30° C. but insufficiently high to cause the particles to become agglomerated, and/or maintaining the polymer at a temperature in this range in the purge vessel, (c) feeding gas to the purge vessel counter-current to the movement of the particulate polymer to remove volatile material therefrom, (d) removing the particulate polymer from the purge vessel, wherein substantially all of the heating of the particles which occurs in the purge vessel is accomplished by preheating the gas fed into the purge vessel.

Abstract: A process for the polymerisation of olefins is disclosed wherein at least part of a stream, preferably a catalytically active stream, withdrawn from a polymerisation reactor is passed through a fractionator so as to remove hydrogen and active fines.

Abstract: A process for the polymerisation of olefins is disclosed wherein at least part of a stream, preferably a catalytically active stream, withdrawn from a polymerisation reactor is passed through a fractionator so as to remove hydrogen and active fines.

Abstract: A process is disclosed for providing a flow of particulate matter such as a catalyst to a reactor, comprising intermittently adding said particulate matter and a diluent to a mixing tank, and continuously withdrawing a slurry of particulate matter in diluent from the mixing tank for introduction into the reactor, wherein prior to each addition of particulate matter and diluent to the mixing tank, the concentration of particulate matter in the diluent already in the mixing tank is measured or calculated, and the amount of particulate matter and diluent subsequently added is measured so as to achieve the same concentration at the end of the addition as that measured or calculated prior to the addition. Preferably measurement of the amount of particulate matter and diluent added to the mixing tank is carried out before any diluent is added to the particulate matter.

Abstract: A process is disclosed for providing a flow of particulate matter such as a catalyst to a reactor, comprising intermittently adding said particulate matter and a diluent to a mixing tank, and continuously withdrawing a slurry of particulate matter in diluent from the mixing tank for introduction into the reactor, wherein prior to each addition of particulate matter and diluent to the mixing tank, the concentration of particulate matter in the diluent already in the mixing tank is measured or calculated, and the amount of particulate matter and diluent subsequently added is measured so as to achieve the same concentration at the end of the addition as that measured or calculated prior to the addition. Preferably measurement of the amount of particulate mailer and diluent added to the mixing tank is carried out before any diluent is added to the particulate matter.

Abstract: A process for the separation of volatile material from particulate polymer discharged from a polymerisation reactor in the form of a polymer slurry and which has been substantially freed from unreacted monomer in an earlier separation step, comprising (a) feeding the particulate polymer to a purge vessel and causing it to move through the vessel in substantially plug-flow mode, (b) heating the particulate polymer in the purge vessel to a temperature greater than 30° C.