Abstract: An olefin polymerization reactor comprising a tubular portion that extends in a vertical direction; a tapered portion disposed inside the tubular portion, an inside diameter of the tapered portion decreasing downwardly, and including a vertically penetrating orifice at a bottom end thereof; a tubular lower deflector disposed above the orifice of the tapered portion, an outside diameter of the tubular lower deflector increasing downwardly, a bottom end thereof being located away from an inner wall of the tubular portion, and including a vertically penetrating orifice at a top end thereof; and an upper deflector disposed above the orifice of the lower deflector, an outside diameter of the upper deflector increasing downwardly, a top end thereof being closed, a bottom end thereof being located away from the inner wall of the tubular portion, and an outside diameter at the bottom end being equal to or greater than an inside diameter of the orifice of the lower deflector.

Abstract: The present invention provides a process for manufacturing polyethylene-diene-copolymer conducted in a plant including at least one compressor unit, at least one preheater unit downstream of the compressor unit and at least one reactor, in particular a reactor, downstream of the compressor unit and the preheater unit. The process comprising the steps of (a) feeding a first feed stream comprising ethylene into the at least one compressor unit and subsequently into the at least one preheater unit, and (b1) feeding a second feed stream including at least one diene comonomer to the first feed stream leaving the at least preheater unit, and feeding the combined feed streams including ethylene and the at least one diene comonomer to the at least one reactor, and/or (b2) feeding a second feed stream including at least one diene comonomer to the at least one reactor at at least one location along the reactor.

Abstract: Techniques are provided for polymerization. A polymerization method may include polymerizing a monomer in a polymerization reactor to produce a slurry comprising polyolefin particles and a diluent, flowing the slurry out of the polymerization reactor through an outlet of the polymerization reactor, receiving the slurry from the outlet into a slurry handling system, conveying a first mixture from the slurry handling system to a diluent and monomer recovery system, and injecting steam into the first mixture downstream of the slurry handling system using a steam injection system.

Abstract: The present invention relates to a method for separating volatile substances, particularly iodine, diiodised aromatic compounds and/or mixtures thereof, from material mixtures containing said compounds. The invention further relates to a device for producing polyarylene sulphides, by means of which volatile substances, particularly iodine and diiodised aromatic compounds, can be separated from the polymers.

Abstract: A method for the delivery of a catalyst to a polymerization reactor is disclosed, comprising: contacting a catalyst with a carrier fluid comprising an inert hydrocarbon in gaseous form, the inert hydrocarbon having a normal boiling point of about ?1° C. to about 81° C.; and flowing the carrier fluid to the polymerization reactor such that the carrier fluid transports the catalyst to the polymerization reactor. A catalyst delivery system is disclosed, comprising: a catalyst vessel for containing a catalyst; a catalyst injection line for delivering the catalyst to a polymerization reactor, the catalyst injection line being in fluid communication with the catalyst vessel and the polymerization reactor; and a carrier fluid line in fluid communication with the catalyst injection line for delivering a carrier fluid comprising an inert hydrocarbon to the catalyst injection line, the inert hydrocarbon having a normal boiling point of about ?1° C. to about 81° C.

Abstract: The present invention provides a method for removing unreacted monomer in polymer using a SCC comprising a housing having a rotation axis; a supply part of at least one polymer formed inside of the housing; at least two spinning cones that are installed so as to have a constant gradient from the upper part to the lower part to the rotation axis, move polymer supplied through the polymer supply part, and rotate around the rotation axis; a fixed cone that is fixed and formed on the inner side of the housing, and provides a pathway for sequentially moving polymer from a spinning cone at the upper part to a spinning cone at the lower part; a product collection part for collecting polymer moved through the spinning cone and the fixed cone; and a driving part for rotating the spinning cone.

Abstract: The present invention relates to a process for manufacturing polyethylene-silane-copolymer conducted in a plant including at least one compressor unit and at least one reactor downstream of the compressor unit. The process includes the steps of (a) feeding a first feed stream including ethylene into the at least one compressor unit and subsequently to the at least one reactor, and (b1) feeding a second feed stream including at least one silane comonomer to the at least one reactor as front feed and/or (b2) feeding a second feed stream including at least one silane comonomer to the at least one reactor at at least one location along the reactor.

Abstract: The invention provides a fluidized bed polymerization reactor, including: a column, in which a liquid distributor and a gas distributor above the liquid distributor are arranged, so that the reaction zone being divided into a first zone and a second zone through the gas distributor; and a circulating unit for circulating the gas material originated from the top zone of the column into the bottom zone thereof in a form of gas-liquid mixture. The gas-liquid mixture is undergone a gas-liquid separation in the bottom zone, the gas phase portion obtained being fed to the gas distributor and then into the second zone while the liquid phase portion obtained being entered into the first zone through the liquid distributor, so that the temperature in the first zone is lower than that in the second zone. Therefore, polymer with a molecular weight distributed in a relatively wide range can be obtained. The invention further provides a method for preparing polymer.

Abstract: A process for continuously mixing at least two fluid streams and splitting the stream of the mixture into at least two partial streams, comprising a) providing streams of the at least two fluids via separated conduits; b) combining the streams of the fluids and forming a homogeneous mixture; c) measuring the pressure in the conduit conveying the mixture of the fluids; d) splitting the stream of the mixture of the fluids into at least two partial streams and feeding each of the partial streams to a conduit equipped with a flow control device controlled by a controller; and e) adjusting the flow rates of the partial streams of the mixture of the fluids by feeding the pressure information measured in step c) as process variable to the controllers controlling the flow control devices, a process for feeding a mixture of at least two fluids via at least two feeding points, an apparatuses for carrying out such processes and a process for polymerizing olefins.

Abstract: Multiple components are selected, conveyed, and measured in a polymerization system. A control system adjusts the system variables to the desired values. Portions of the components can be fed to a pre-contactor before introduction into the polymerization reactor. The catalyst component concentrations and residence times are tightly controlled in the pre-contactor to affect product properties. The pre-contactor can be a single or multiple combinations of a CSTR or plug flow pre-contactors.

Abstract: A catalyst composition may include a precontacted mixture of an olefin polymerization catalyst and an agent including an ammonium salt. The catalyst activity of the catalyst composition in the presence of water may be greater than if no ammonium salt were present in the catalyst composition. The ammonium salt may include a tetraalkylammonium salt, and the olefin polymerization catalyst may include a metallocene compound.

Abstract: Methods of forming a polyarylene sulfide and systems as may be utilized in carrying out the methods are described. Included in the formation method is a filtration process for treatment of a mixture, the mixture including a polyarylene sulfide, a salt byproduct of the polyarylene sulfide formation reaction, and a solvent. The filtration process includes maintaining the downstream side of the filter medium at an increased pressure. The downstream pressure can such that the boiling temperature of the mixture at the downstream pressure can be higher than the temperature at which the polyarylene sulfide is insoluble in the solvent.

Abstract: The present disclosure provides a system for recovering emissions generated from an olefin polymerization process, comprising: a devolatilizer for receiving a fresh sweep gas and emissions generated from the olefin polymerization process and outputting a first fluid and a polyolefin resin; a compression refrigeration unit including a compression device and a first heat exchange device, for receiving said first fluid and outputting a first gas-liquid mixture; a first gas-liquid separation device for separating the first gas-liquid mixture and outputting a first recovery product and a first gas phase composition; a first gas separation device for receiving the first gas phase composition, removing small molecular substances therefrom, and outputting a composition rich in small molecular gases and a second gas phase composition rich in hydrocarbons; and a second gas separation device having a second heat exchange device, a second gas-liquid separation device, and a first gas expansion device.

Abstract: The present invention provides a patterned polarization converter having multiple domains that can be used to convert input linear polarized light to output light with spatially varying polarization states, including domains that produce linearly polarized light and domains that produce circular polarized light based on the patterning of the domains. A patterned polarization converter having multiple domains may be used in a polarization sensor application capable of detecting the polarization state of input light. The present invention further provides patterned radial and azimuthal polarization converters, which have utility in applications such as optical tweezers. Additionally, patterned polarization converters may be used to fabricate more patterned polarization converters having the same pattern using one-step photoalignment to copy the pattern of an existing patterned polarization converter to an unpatterned photoalignment layer.

Abstract: Disclosed herein is a method of preparing prepolymer particles. The method includes injecting a prepolymer in a solution state by bottom-up type injection to form prepolymer particles by removing a solvent from the prepolymer in a solution state. The method can prepare prepolymer particles, which can be used in solid-state polymerization, using a bottom-up type flash process.

Abstract: A styrene monomer reclamation process and system is described. The styrene monomer reclamation process includes providing a waste plastic. The waste plastic includes styrenic polymers. The waste plastic is formed into polymer particles. At least a portion of the polymer particles are dissolved in a solvent to form a polymer stream. The dissolved polymer particles are depolymerized to form a styrene monomer stream.

Abstract: The present invention relates to an apparatus and process for polymerizing olefins. One embodiment comprises polymerizing at least one monomer in a first loop reactor in the presence of a catalyst to produce a first polyolefin fraction. A portion of the first polyolefin fraction is transferred to a second loop reactor, connected in series with the first loop reactor. The process further comprises polymerizing in the second loop reactor at least one monomer in the presence of a catalyst to produce a second polyolefin fraction in addition to the first polyolefin fraction. The combination of the first and second polyolefin fractions can produce a polymer resin fluff having bimodal molecular weight distribution.

Abstract: The invention relates to a process for preparing polymers from monomers and/or oligomers by adding a liquid comprising the monomers and/or oligomers dropwise to a continuous liquid phase in a reactor, the continuous liquid phase being immiscible with the liquid comprising the monomers and/or oligomers, and the monomers and/or oligomers reacting in the continuous liquid phase to give the polymer. The liquid comprising the monomers and/or oligomers is shaped to droplets outside the continuous liquid phase, which are subsequently introduced into the continuous liquid phase. The invention further relates to a reactor for performing the process, comprising a tube through which a continuous liquid phase flows, and means of generating droplets, the means of generating droplets being arranged such that the droplets are generated outside the continuous liquid phase and then introduced into the continuous liquid phase.

Abstract: A process to produce polycarbamate comprising providing urea in liquid form; and adding the urea in liquid form to a polyol in a reduced gradient profile to form polycarbamate product is provided. Also provided are: (a) a reaction product of the process and (b) an apparatus for operating the process.

Abstract: The present invention relates to a method as well as an apparatus for fixed phase polycondensation of polyesters, preferably polyethylene terephthalate and/or copolymers thereof, characterised in that the fixed phase polycondensation is performed with polyester prepolymer particles in a reaction chamber in which an absolute pressure predominates in the range from 10 mbar to 200 mbar, preferably 20 to 150 mbar, and a process gas flow in the range of an R-value of 0.005 to 0.05.

Abstract: A method for producing a polymer, including: (i) continuously supplying and bringing at least a first monomer, which is ring-opening polymerizable, and a compressive fluid into contact with each other, to thereby allow the first monomer to carry out ring-opening polymerization to continuously generate an intermediate; and (ii) bringing the intermediate and a second monomer, which is identical to or different from the first monomer in kind, into contact with each other, to thereby allow the intermediate and the second monomer to carry out polymerization.

Abstract: The present disclosure generally provides methods and apparatus for efficiently crosslinking silicon carbide fiber precursor polymers with electron beam radiation. The methods and apparatus utilize a platform containing silicon carbide fiber precursor polymer. The temperature of the platform is regulated while the silicon carbide fiber precursor polymer is irradiated to thereby regulate the temperature of the irradiated silicon carbide fiber precursor polymer thereon. In this way, the temperature of the irradiated silicon carbide fiber precursor polymer is regulated via the platform both during and after it is subjected to radiation. At least one of the platform and the e-beam radiation mechanism may be translated with respect to the other to irradiate different portions of the silicon carbide fiber precursor polymer and, ultimately, the entirety of the silicon carbide fiber precursor polymer contained on the platform.

Abstract: A method for preparing latex emulsion compositions uses a steam-driven emulsification process, and a method for preparing a toner using the latex emulsion compositions. The method includes contacting a resin with an organic solvent and optionally a neutralization agent; and applying steam or heated water vapor to contact the resin to prepare a latex emulsion. An apparatus can perform the method.

Abstract: An electrophoresis gel, in which a good pH gradient or concentration gradient of a gel-forming monomer is formed, is produced. In addition, the production efficiency of an electrophoresis reaction tool is improved and the production processes are simplified. At least one of a first process to add a gel-forming monomer to a first solution containing an initiator to initiate polymerization of the gel-forming monomer by external energy in such a way that a pH gradient or concentration gradient of the gel-forming monomer is formed and a second process to initiate the polymerization of the above-described gel-forming monomer in the first solution, to which the above-described gel-forming monomer has been added, by using the above-described external energy is included.

Abstract: Processes and systems for the production for pressure management of a polymerization product flowing from a loop polymerization reactor to a separation vessel in a slurry polymerization system are disclosed herein. For example, a process comprises withdrawing the polymerization product from a loop polymerization reactor, and conveying the withdrawn polymerization product to a separation vessel via a first pressure differential and a second pressure differential. The withdrawn polymerization product may flow through the first pressure differential before flowing through the second pressure differential, and the first pressure differential may be less than the second pressure differential.

Abstract: A method for the delivery of a catalyst to a polymerization reactor is disclosed, comprising: contacting a catalyst with a carrier fluid comprising an inert hydrocarbon in gaseous form, the inert hydrocarbon having a normal boiling point of about ?1° C. to about 81° C.; and flowing the carrier fluid to the polymerization reactor such that the carrier fluid transports the catalyst to the polymerization reactor. A catalyst delivery system is disclosed, comprising: a catalyst vessel for containing a catalyst; a catalyst injection line for delivering the catalyst to a polymerization reactor, the catalyst injection line being in fluid communication with the catalyst vessel and the polymerization reactor; and a carrier fluid line in fluid communication with the catalyst injection line for delivering a carrier fluid comprising an inert hydrocarbon to the catalyst injection line, the inert hydrocarbon having a normal boiling point of about ?1° C. to about 81° C.

Abstract: Process and apparatus for recovering polymer from a gas phase reactor having a distribution plate via an outlet vessel comprising at least one apparatus for the breakup of polymeric agglomerates, the apparatus further comprising a feed pipe connecting the gas phase reactor and the outlet vessel a return gas line connecting the gas phase reactor and the outlet vessel, means for varying the flow rate through the return gas line from the outlet vessel to the gas phase reactor, and means for varying the outlet rate of polymer product from the outlet vessel.

Abstract: Provided are processes and apparatuses for continuous solution polymerization which can mitigate fouling during the production of propylene-based polymers.

Abstract: An ethylene polymerization system is provided with a quench system and that cools the product mixture entering the separation system with a reduced load on the first compressor of the system. The system includes first and second compressors, a high pressure reactor; a high pressure let down valve through which the product mixture from the high pressure reactor flows, and a separation system that separates gas from the product mixture. The quench system includes a pump having a suction inlet that receives all or substantially all of the low pressure flow of monomer from the first compressor. The system provides quenching of the product stream while allowing the first compressor to be operated at a discharge pressure lower than the suction pressure of the second compressor, thereby conserving energy.

Abstract: Methods and devices for performing chemical reactions under controlled temperature are described. In one embodiment, the devices provided by the invention comprise a housing dimensioned to hold a reaction chamber disposed within an interior volume of the housing. The reaction chamber has thermally conductive interior and exterior surfaces defining an internal volume therein at a first temperature. The device also includes at least one temperature-control substance at a second temperature received into said bladder and expels said temperature-control substance, the bladder expands to about substantially at least a portion of said exterior surfaces of said reaction chamber to enable thermal exchange between said temperature-control substance and the said internal volume of reaction chamber.

Abstract: This disclosure provides an integrated and automated sample-to-answer system that, starting from a sample comprising biological material, generates a genetic profile in less than two hours. In certain embodiments, the biological material is DNA and the genetic profile involves determining alleles at one or a plurality of loci (e.g., genetic loci) of a subject, for example, an STR (short tandem repeat) profile, for example as used in the CODIS system. The system can perform several operations, including (a) extraction and isolation of nucleic acid; (b) amplification of nucleotide sequences at selected loci (e.g., genetic loci); and (c) detection and analysis of amplification product. These operations can be carried out in a system that comprises several integrated modules, including an analyte preparation module; a detection and analysis module and a control module.

Abstract: A method and an apparatus for the non-thermal plasma processing of halogenated compounds. A non-thermal plasma reactor (110) with a non-thermal plasma reaction zone (116) may process one or more halogenated compounds diluted in an inert carrier gas in a gas stream (114). An alkane gas may also be added to the gas stream (114) for some halogenated compounds. A uniform polymer product may be deposited within the non-thermal plasma reactor apparatus, the polymer being derived from molecular fragments of the reactant halogenated compound and the reactant alkane gas if present. The non-thermal plasma may be provided by the use of a dielectric barrier discharge technique utilizing two co-axial dielectric tubes (126, 128) with corresponding high voltage (136) and ground (138) electrodes.

Abstract: An integrated facility is disclosed for simultaneous production of butanal and methacrylic acid products where the facility utilizes a mixed methacrolein and isobutanal stream to make methacrylic acid. The facility is also designed to utilize downstream n-butanal products such as n-butanol and/or 2-ethyl-hexanol to make butyl-methacrylates and 2-ethyl-hexyl-methacrylate. A method is also disclosed which integrates the production of butanal derived products and methacrylic acid derived products.

Abstract: Processes and systems for the production for pressure management of a polymerization product flowing from a loop polymerization reactor to a separation vessel in a slurry polymerization system are disclosed herein. For example, a process comprises withdrawing the polymerization product from a loop polymerization reactor, and conveying the withdrawn polymerization product to a separation vessel via a first pressure differential and a second pressure differential. The withdrawn polymerization product may flow through the first pressure differential before flowing through the second pressure differential, and the first pressure differential may be less than the second pressure differential.

Abstract: Injection nozzles for use in a gas distribution device are disclosed. In one aspect, the injection nozzle may include: a tube having a fluid inlet and a fluid outlet; wherein the inlet comprises a plurality of flow restriction orifices. In another aspect, embodiments disclosed herein relate to an injection nozzle for use in a gas distribution device, the injection nozzle including: a tube having a fluid inlet and a fluid outlet; wherein the fluid inlet comprises an annular orifice surrounding a flow restriction device. Injection nozzles according to embodiments disclosed herein may be disposed in a gas distribution manifold used in a vessel, for example, for conducting polymerization reactions, spent catalyst regeneration, and coal gasification, among others.

Abstract: A process for making a low density polymer in a polymerization reactor system, the process comprising polymerizing an olefin monomer, and optionally an olefin comonomer, in the presence of a diluent in a polymerization reactor to make a polymerization product slurry consisting of a liquid phase and a solid phase, wherein the solid phase comprises an olefin polymer having a density of between about 0.905 g/cm3 to about 0.945 g/cm3; and discharging the polymerization product slurry from the polymerization reactor through a continuous take-off valve to make a mixture further comprising a vapor phase. The mixture comprises a pressure less than a bubble point pressure of a component in the polymerization product slurry.

Abstract: A method for improving the prediction of polymer properties and a system having improved polymer property prediction capabilities is provided. The method for improving the prediction of polymer properties comprises: (1) providing a polymer; (2) providing a prediction model; (3) utilizing said prediction model to define an average polymer property prediction value; (4) determining a feasible range; (5) measuring one or more properties of said polymer; (6) determining whether said one or measured polymer properties are within said feasible range: (7) validating said one or more measured polymer properties if said one or more measured polymer properties fall within the feasible range or invalidating said one or more measured polymer properties if said one or more measured polymer properties fall outside of the feasible range; (8) optionally updating said prediction model; (9) repeating said previous steps at least one or more times; and (10) thereby improving the prediction of polymer properties.

Abstract: Process and apparatus for discharging polyolefin particles from a gas-phase polymerization reactor of a pressure from 1.0 MPa to 10 MPa to a discharge vessel of a pressure from 0.1 MPa to 1.0 MPa wherein the discharging is carried out discontinuously through at least two discharge lines in which the polyolefin particles are transported horizontally or upwards.

Abstract: To pvodie a method for producing a polymer, which contains continuously supplying and bringing at least a ring-opening polymerizable monomer and a compressive fluid into contact with each other, to thereby allow the ring-opening polymerizable monomer to carry out ring-opening polymerization to continuously generate a polymer.

Abstract: Systems and methods for processing and analyzing samples are disclosed. The system may process samples, such as biological fluids, using assay cartridges which can be processed at different processing locations. In some cases, the system can be used for PCR processing. The different processing locations may include a preparation location where samples can be prepared and an analysis location where samples can be analyzed. To assist with the preparation of samples, the system may also include a number of processing stations which may include processing lanes. During the analysis of samples, in some cases, thermal cycler modules and an appropriate optical detection system can be used to detect the presence or absence of certain nucleic acid sequences in the samples. The system can be used to accurately and rapidly process samples.

Abstract: A manufacturing system for producing polyolefin includes a polymerization reactor, a flash chamber, and a purge column. In certain embodiments, the purge column may receive a solids stream directly from the flash chamber. Further, the purge column may function as a feed tank for an extruder within an extrusion/loadout system. According to certain embodiments, the manufacturing system may be configured to consume less than 445 kilowatt-hours of energy per metric ton of polyolefin produced based on consumption of electricity, steam, and fuel gas.

Abstract: The invention relates to a catalyst metering device with a valve formed of an iron-based alloy steel hardened to a Rockwell hardness C of at least 60. The device can be used for metering of a catalyst for an ethylene polymerization reaction. The invention further relates to ethylene polymerization wherein the catalyst is metered in a catalyst metering device with a iron-based alloy steel hardened valve, as well as to a ethylene polymerization reactor comprising such a catalyst metering device.

Abstract: A process for producing water-absorbing polymer particles, wherein a polymer gel is removed from a polymerization reactor, stored intermediately as a particulate polymer gel in a delay vessel, removed by means of a first conveying device at the lower end of the delay vessel and dried, the intermediately stored particulate polymer gel being conveyed within the delay vessel by means of at least one second conveying device above the first conveying device in the direction of the first conveying device.

Abstract: Techniques are provided for catalyst preparation. A system for catalyst preparation may include an agitator disposed inside a polymerization catalyst tank and configured to mix a polymerization catalyst and a solvent to generate a polymerization catalyst solution. The system may also include a heating system coupled to the polymerization catalyst tank and configured to maintain a temperature of the polymerization catalyst solution above a threshold. The system may also include a precontactor configured to receive feed streams comprising an activator and the polymerization catalyst solution from the polymerization catalyst tank to generate a catalyst complex. The system may also include a transfer line configured to transfer the catalyst complex from an outlet of the precontactor to a reactor.

Abstract: A polymerization reactor system includes features for operating two or more reactors in series or parallel. The system includes a discharge line coupled to an outlet of a first polymerization reactor, a first conduit connecting the first polymerization reactor to a second polymerization reactor via the discharge line, a second conduit connecting the first polymerization reactor to a flashline apparatus via the discharge line, and a diverter valve coupling the first and second conduits to the discharge line. The diverter valve is configured to selectively open the discharge line to the first conduit and close the discharge line to the second conduit in a first valve state and to selectively open the discharge line to the second conduit and close the discharge line to the first conduit in a second valve state. The diverter valve is capable of switching between the first and second valve states.

Abstract: The present invention relates to a process for the production of halogenated butyl rubber and an apparatus for the production of rubber cement for use in the production of halogenated butyl rubber. The process and apparatus permit direct mixing of aqueous rubber slurry with a non-halogenated organic solvent to make a rubber cement solution. The water layer is then separated from the partially dissolved rubber cement and the cement phase is sent for halogenation. The apparatus is an enclosed vessel comprised of at least one dissolving zone and at least one separator zone. The process and apparatus advantageously employ recycle of rubber cement in order to disrupt an interface layer that forms between the water and rubber cement, to thereby improve continuously operation of the process.

Abstract: The present invention relates to a process of forming a polymer, the process comprising polymerizing olefin monomers to form a reaction mixture, treating the reaction mixture to form a first polymer-rich phase, treating the first polymer-rich phase to form a second polymer-rich phase, and devolatilizing the second polymer-rich phase, the process further comprising at least one step of adjusting the temperature of a first and/or the second polymer-rich phase before the devolatilization. The present invention also relates to a plant that is useful for the process provided above.

Abstract: Methods and systems for preparing catalyst, such as chromium catalysts, are provided. The valence of at least a portion of the catalyst sent to an activator is changed from Cr(III) to Cr(VI). The catalyst is prepared or activated continuously using a fluidization bed catalyst activator.

Abstract: Apparatus and methods utilizing infrared energy for heating reactions associated with peptide synthesis, such as activation, deprotection, coupling, and cleavage. Thorough agitation of the contents of reaction vessels during heating and real-time monitoring and adjustment of temperature and/or reaction duration are also described. Existing peptide synthesizers may be retrofitted to include an infrared energy source.

Abstract: A process for the gas-phase copolymerization of: (a) propylene, (b) at least one C4-C8 ?-olefin, and (c) optionally ethylene, the process being carried out in a reactor having two interconnected polymerization zones, wherein the growing polymer particles flow through the first of said polymerization zones (riser) under fast fluidization conditions, leave said riser and enter the second of said polymerization zones (downcomer) through which they flow downward in a densified form, leave said downcomer and are reintroduced into said riser, thus establishing a circulation of polymer between the riser and the downcomer, the gas mixture present in the riser being at least partially prevented from entering the downcomer by introducing into the upper part of said downcomer a liquid barrier having a composition different from the gaseous mixture present in the riser and comprising at least one C4-C8 ?-olefin in a total amount of from 0.1% to 35% by mol.