Purified polymer, method and apparatus for the production thereof

Abstract

The present disclosure relates to a method of producing a polymer, in particular a purge polymer, comprising producing the polymer in a polymerization reactor in the presence of a catalyst at a first temperature, where the catalyst has a temperature dependent maximum catalyst capability, and where the polymer has a temperature dependent adhesion limit; discharging the polymer from the polymerization reactor into a first process vessel; at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a purge gas stream in a first process vessel; transferring the polymer from the first process vessel to a second process vessel; contacting the polymer with a purge gas stream in a second process vessel; and recovering a polymer product comprising the polymer from which the undesired compounds have been purged.

Description

Technical Field

[0001] The present disclosure relates to methods and systems for producing polymer compounds that are purified of volatile organic compounds (VOCs), and polymers obtained therefrom. Background Art

[0002] Polymers including polyolefin resins (e.g. polyethylene or polypropylene) can be manufactured according to various catalytic methods, including liquid phase and gas phase methods. In such methods, the polymer product discharged from the reaction zone comprises solid polymer pellets and volatile non-polymer components such as monomers, comonomers, diluents and catalysts. These volatile substances can dissolve, combine or otherwise attach to the vapor space outside the polymer pellets and / or polymer pellets. Heavy olefin monomers such as 1-hexene, which are often used as comonomers in polyethylene polymerization processes, are particularly soluble in low-density polyethylene. The method for removing these volatile substances from the polymer product is referred to as resin degassing or purification (purging) in the art.

[0003] The polymer product can be purified by decompressing the resin and stripping with a light purge gas such as nitrogen. In these methods, the polymer product is transferred to a relatively low pressure purge bin. The polymer product enters the upper part of the container and is subjected to the action of the purge gas, which enters the container through holes or openings at the bottom of the container and may enter the container along the sides and other areas. It sweeps through the pelletized resin and leaves the purge bin. The purified polymer product is discharged and transmitted to a further downstream process. The purge gas exhaust stream containing the purge gas and the volatile substances purified, particularly volatile organic compounds (VOCs), is usually subjected to downstream processing in a recovery system to remove VOCs, which can be recycled to the reactor, after which the remaining exhaust stream is burned. Background references to polymer purification and recovery systems include U.S. Pat. Nos. 3,797,707; 4,286,883; 4,372,758; 4,731,438; 4,758,654; 5,292,863; 5,462,351; 7,957,947 and 8,470,082; EP 2 172 494A; WO 2018 / 204026; and R. W. Baker and M. Jacobs, “Improve Monomer Recovery from Polyolefin Res in Degassing,” Hydrocarbon Processing, March 1996.

[0004] Optimizing the recovery of VOCs from purified polymer products is challenging in view of operating equipment and VOC content limitations. For environmental and safety reasons, VOCs in polymer products and combustion gases must be removed or reduced to appropriate levels before exposure to the atmosphere. In addition, it is economically advantageous to recover as much VOC as possible to minimize the use of additional raw materials and compression and pumping energy.

[0005] Attempts have been made to manage the VOC content in polyolefins through improved purification methods and systems. For example, U.S. Patent Nos. 7,957,947; 8,249,748; and 8,543,242 relate to techniques for reducing the VOC content in polyolefins by constructing and implementing a purification model column to calculate or estimate the VOC content in the polyolefin leaving the purification column. U.S. Patent No. 10,035,864 relates to a control method and system for purging a polymer product of volatile materials, particularly a polymer product containing polyethylene produced in a fluidized bed reactor.

[0006] Other references relate to post-treatment of polymers, including U.S. Patent Nos. 8,344,099; 7,786,254 and 9,216,548, WO 2008 / 080782; CN109694421; CN109575171; CN103124747; CN102453160; CN102827450; CN101987900; CN105085723; CN108466383; CN101613426.

[0007] Smell and VOC remaining in any type of polymer (particularly polyolefin) are the fields that are increasingly concerned in polymer production. The traditional design of the method for producing polyolefin is usually only focused on removing light VOC (6-carbon molecules and lighter), which is mainly for the safety reasons in the production and / or transportation of product. The new design of production plant and method is needed to reduce the smell and VOC in these products to the new lower level of consumer expectation in these markets (especially in automobile, nonwoven material and household appliance market). Because common facilities in industry use external heat source to drive the devolatilization of polymer, it is also necessary to minimize the amount of energy used during polymer production to achieve these purposes. Summary of the invention

[0008] The present disclosure relates to methods and systems for producing polymer compounds that scavenge VOCs, and polymers obtained therefrom.

[0009] The non-limiting method of the present disclosure for producing a polymer, especially purifying a polymer, comprises the following steps: i) in a polymerization reactor, in the presence of a catalyst, at a first temperature (T 1) wherein the catalyst has a maximum catalyst capacity that depends on temperature, and wherein the polymer has a stickiness limit that depends on temperature; ii) discharging the polymer from the polymerization reactor into a first process vessel; iii) at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a first purge gas stream in the first process vessel; iv) transferring the polymer from the first process vessel to a second process vessel; v) contacting the polymer with a second purge gas stream in the second process vessel; and vi) recovering a polymer product comprising the polymer from which the undesirable compounds have been purged; wherein the first temperature is increased to a maximum of the catalyst capacity and / or the stickiness limit of the polymer to prevent plugging and fouling; and wherein steps ii) to v) are operated while maintaining the polymer at a second temperature (T 2 ) so that T 1 -20℃≤T 2 ≤T 1 and / or 70℃≤T 2 ≤T 1 , wherein T in step ii) 2 may be different from T in step v) 2 .

[0010] The non-limiting system of the present disclosure for producing purified polymers comprises: a polymerization reactor adapted to operate at a first temperature and for producing a polymer; a first process vessel configured to at least partially remove undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, the first process vessel comprising a first polymer inlet fluidly connected to the polymerization reactor for receiving the polymer, a first polymer outlet for discharging the polymer having a reduced content of undesirable compounds, a first waste gas outlet for venting at least some of the undesirable compounds, and optionally a first purge gas inlet for introducing a first purge gas; a first process vessel configured to purify the polymer having a reduced content of volatile organic compounds and / or residual polymerization reactants and / or odorous compounds; a first process vessel configured to at least partially remove undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, the first process vessel comprising a first polymer inlet fluidly connected to the polymerization reactor for receiving the polymer, a first polymer outlet for discharging the polymer having a reduced content of undesirable compounds, a first waste gas outlet for venting at least some of the undesirable compounds, and optionally a first purge gas inlet for introducing a first purge gas; a second process vessel for producing a polymer having a reduced content of undesirable compounds, comprising a second polymer inlet fluidly connected to the first process vessel for receiving the polymer having a reduced content of undesirable compounds, a second polymer outlet for discharging the polymer purified of undesirable compounds, a second purge gas inlet for introducing a second purge gas, and a second waste gas outlet for discharging the second purge gas with the undesirable compounds purified from the polymer; a purge gas system configured to introduce the second purge gas into the second process vessel; a purge polymer recovery section fluidly connected to the second process vessel; wherein the system is configured to maintain the polymer at a second temperature (T ) while flowing the polymer from the polymerization reactor to the second process vessel 2 ) so that T 1 -20℃≤T2 ≤T 1 and / or 70℃≤T 2 ≤T 1 .

[0011] The non-limiting method of the present disclosure for producing polymers, particularly purifying polymers, comprises the following steps: i) producing a polymer in a polymerization reactor in the presence of a catalyst; ii) discharging the polymer from the polymerization reactor into a first process vessel; iii) at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a first purified gas stream in the first process vessel; iv) transferring the polymer from the first process vessel to a second process vessel; v) contacting the polymer with the first purified gas stream in the second process vessel; and vi) recovering the polymer from which the undesirable compounds have been purified; wherein step iii) comprises flowing the polymer into the first process vessel in a plug flow manner and delivering superheated steam to the polymer in a countercurrent manner.

[0012] These and other features and properties of the methods and systems disclosed in the present disclosure and their advantageous applications and / or uses will be apparent from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] To assist one of ordinary skill in the relevant art in making and using the subject matter herein, reference is made to the accompanying drawings. The following drawings are included to illustrate certain aspects of the present disclosure and should not be construed as an exclusive configuration. The disclosed subject matter is capable of significant modifications, alterations, combinations, and equivalences in form and function as will occur to one of ordinary skill in the art having the benefit of this disclosure.

[0014] Figure 1 A schematic diagram illustrating a first non-limiting embodiment of a system that may be used in a method of purifying polymer production according to the present disclosure.

[0015] Figure 2 A schematic diagram illustrating a second non-limiting embodiment of a system that may be used in a method of purifying polymer production according to the present disclosure.

[0016] Figure 3 A schematic diagram illustrating a third non-limiting embodiment of a system that may be used in a method of purifying polymer production according to the present disclosure.

[0017] Figure 4 A schematic diagram illustrating a fourth non-limiting embodiment of a system that may be used in a method of purifying polymer production according to the present disclosure.

[0018] Figure 5A schematic diagram illustrating a fifth non-limiting embodiment of a system that may be used in a method of purifying polymer production according to the present disclosure. DETAILED DESCRIPTION

[0019] The present disclosure relates to methods and systems for producing polymer compounds that scavenge VOCs, and polymers obtained therefrom.

[0020] For purposes of this disclosure and the claims thereto, the following definitions are made.

[0021] The term "polymer" refers according to IUPAC to substances consisting of macromolecules. A macromolecule is a molecule of high relative molecular mass, the structure of which consists essentially of multiple repetitions of units derived actually or conceptually from molecules of low relative molecular mass.

[0022] When a polymer or oligomer is referred to as comprising an olefin, the olefin present in the polymer or oligomer is a polymerized or oligomeric form of the olefin, respectively. The term polymer is intended to encompass homopolymers and copolymers. The term copolymer includes any polymer having two or more different monomers in the same chain, and encompasses random copolymers, statistical copolymers, interpolymers, and (true) block copolymers.

[0023] When a polymer blend is referred to as containing a certain percentage of a monomer, the percentage of the monomer is based on the total amount of monomer units in all polymer components of the blend. For example, if the blend contains 50 wt% of polymer A having 20 wt% of monomer X, and 50 wt% of polymer B having 10 wt% of monomer X, then the blend of polymers A and B contains 15 wt% of monomer X. The blend components can be miscible, resulting in a single homogeneous phase, or immiscible, resulting in the presence of two or more morphological phases, wherein each phase contains a different ratio of polymers.

[0024] "Polyolefin" is a polymer comprising at least 50mol% of one or more olefin monomers. Preferably, polyolefin comprises at least 60mol%, or at least 70mol%, or at least 80mol%, or at least 90mol%, or at least 95mol%, or 100mol% of one or more olefin monomers. Preferably, olefin monomers are selected from C2-C20 olefins, or C2-C16 olefins, or C2-C10 olefins. More preferably, olefin monomers are selected from ethylene, propylene, 1-butene, 1-hexene and 1-octene. Polyolefin can also comprise at most 50mol% of one or more diene monomers.

[0025] The term "polyethylene" means a polymer or copolymer comprising at least 50 mol% ethylene units, preferably at least 70 mol% ethylene units, more preferably at least 80 mol% ethylene units, even more preferably at least 90 mol% ethylene units, even more preferably at least 95 mol% ethylene units or 100 mol% ethylene units in the case of a homopolymer.

[0026] The term "polypropylene" means a polymer consisting of at least 50 mol% (preferably at least 60 mol%, more preferably at least 70 mol%, more preferably at least 80 mol%, even more preferably at least 90 mol%, even more preferably at least 95 mol% or 100 mol%) propylene units and having less than 20 wt% of ethylene units.

[0027] The term "impact copolymer" refers to two or more polymers, wherein one polymer can be dispersed in another polymer, and usually one polymer constitutes a matrix phase and another polymer constitutes an elastomeric phase. The matrix phase can be a crystalline polymer, such as a polypropylene homopolymer or a polypropylene copolymer, and the polymer constituting the elastomeric phase can be a rubber or an elastomer. The polymer forming the elastomeric phase can include an impact copolymer of about 5 to about 50 weight %, about 10 to 45 weight % and about 10 to 40 weight %. Exemplary impact copolymers may include a blend of a propylene homopolymer and a propylene / ethylene copolymer (i.e., poly(propylene-to-propylene / ethylene) impact copolymer). Impact copolymers can be produced by mechanical blending or by using a multistage reactor. Usually impact copolymers are formed in a two-stage or multistage process.

[0028] The manner in which the ICPs are produced is not critical to the present disclosure. They can be produced by conventional melt blending of the individual components, by "reactor blending" ("reactor production"), by a combination of these two methods, or by other means that achieve discrete elastomeric regions dispersed within a substantially continuous polypropylene matrix. "Reactor blend" means the in-situ production of the polypropylene and rubber components during a single-stage or multistage polymerization process. The rubber phase is present in discrete domains dispersed throughout the polypropylene phase. Most commonly, the rubber will be an ethylene-propylene rubber or an ethylene-propylene terpolymer rubber, however, other rubber compositions may be used. As used in this specification and the appended claims, the term "rubber" shall mean any substantially non-crystalline polymer component having a low glass transition temperature (typically ≤-35°C), typically a copolymer of propylene-derived units and at least one other monomer-derived unit selected from ethylene and at least one C4-C10 alpha-olefin.

[0029] ICPs can be prepared using any suitable polymerization process. In one embodiment, the process includes the use of a metallocene catalyst system. Such systems are well known in the art and are capable of producing ICPs having certain desired properties.

[0030] In one desired embodiment, the metallocene produced impact copolymer is reactor produced wherein the "polypropylene component" of the copolymer is produced in one stage and the "rubber component" is produced in the presence of the polypropylene component in another stage.

[0031] In another embodiment, the polymerization process for preparing the ICP comprises the use of a Ziegler-Natta catalyst system. Examples of suitable catalyst systems and production methods can be found in U.S. Pat. Nos. 6,087,459, 5,948,839, 4,245,062, and 4,087,485. Examples of catalyst systems that can be used to form impact copolymers are the Ziegler-Natta catalyst systems described in U.S. Pat. Nos. 4,990,479, 5,159,021, and 6,111,039.

[0032] As used herein, an "olefin / polyolefin separation" step, apparatus, device or stage refers to any method or device for separating unreacted olefin monomer from the formed polyolefin, e.g., from the polymerization medium, such as by physical separation and / or by heating the mixture and / or changing the pressure of the mixture, and as used herein preferably refers to separating propylene from the formed polypropylene, ethylene-propylene copolymer and / or impact copolymer.

[0033] The term "polymerization reactor" as used herein encompasses any type of reactor such as, but not limited to, a stirred tank reactor, a loop reactor, a fluidized bed reactor, a tubular reactor, a tower reactor or an extruder reactor. It is preferred that the polymerization reactor system is a gas phase polymerization reactor system.

[0034] As used herein, the term "volatile material" refers to a component or compound that has a low relative boiling point compared to its surrounding components or compounds.

[0035] As used herein, the term "volatile organic compound" or "VOC" refers to volatile organic compounds. 1 -C 16 Hydrocarbons. VOCs may be saturated or unsaturated, inert or non-inert, may have a boiling point of less than 260°C, may have a saturated vapor pressure of 133.32 Pa or more at room temperature (23±2°C) and may exist in the air in their gas phase at normal temperature (25±2°C). 1 -C 16 Hydrocarbons may also contain any element selected from halogens, oxygen, sulfur, phosphorus, silicon dioxide or nitrogen. Other compounds that cause odors, such as non-organic sulfur or nitrogen containing compounds, may be considered VOCs. As used herein, VOCs do not include carbon oxides (CO and CO2), inorganic carbonates or bicarbonates. VOCs include organic compounds with or without odor.

[0036] The term "C6-C16 volatile organic compounds" shall mean VOCs containing 6-16 carbon atoms, including but not limited to benzene, toluene, ethylbenzene, xylene, and styrene.

[0037] The term "C1-C16 volatile organic compounds" shall mean VOCs containing 1-16 carbon atoms, including but not limited to benzene, toluene, ethylbenzene, xylene, styrene, formaldehyde, acetaldehyde, and acrolein.

[0038] As used herein, the term "odorous compound" refers to a molecule or substance that a person can smell. Those compounds are vaporized by evaporation or sublimation at ambient temperature. Such compounds may be organic or not organic, and may have a molecular weight lower than 300. Not all volatile compounds have odor. The limiting examples of such odorous compounds include acetaldehyde, allyl mercaptan, ammonia, amyl mercaptan, benzyl mercaptan, butylamine, cadaverine, chlorine, chlorophenol, crotyl mercaptan, dibutylamine, diisopropylamine, dimethyl sulfide, diphenyl sulfide, ethylamine, ethyl mercaptan, hydrogen sulfide, indole, methylamine, methyl mercaptan, putrescine, pyridine, skatole, sulfur dioxide, tert-butyl, thiophenol, triethylamine, some hydrocarbons, some aromatic compounds, some esters and some ketones, etc.

[0039] The term "undesirable compounds" in the context of the present disclosure includes at least one of volatile organic compounds, odorous compounds and residual polymerized reactants.

[0040] As used herein, the term "purge" refers to the process of removing unwanted dissolved and undissolved gases, including VOCs and / or other volatile compounds, from the gas-filled interstitial spaces of a solid pelletized polymer resin. In addition to interstitial air, volatile compounds such as VOCs may also be dissolved in the resin. The purge operation consists of generating sufficient driving force to cause adsorbed volatile compounds to diffuse out of the resin.

[0041] As used herein, the term "purified polymer" or "degassed polymer" refers to a polymer that has been treated by a purification operation to partially or completely remove volatile compounds and odorous compounds from the polymer.

[0042] As used herein, the term "purge gas" refers to any gas suitable for purging polymers, such as an inert gas including nitrogen or argon, or small hydrocarbon molecules such as methane, ethane, ethylene, propane or propylene. The purge gas may also contain a certain percentage of moisture or steam.

[0043] As used herein, the term "superheated steam" refers to steam heated to a temperature above its vaporization point at the absolute pressure at which the temperature is measured.

[0044] The term "plug flow" as used herein refers to a model of the velocity profile of a fluid flowing through a pipe or process vessel of substantially constant cross-section, wherein the velocity of the fluid is assumed to be constant across any cross-section of the pipe or process vessel perpendicular to the axis of the pipe or process vessel.

[0045] The term "heat exchanger" refers to a device designed to efficiently transfer or "exchange" heat from one substance to another. Exemplary heat exchanger types include parallel or countercurrent heat exchangers, indirect heat exchangers (e.g., spiral wound heat exchangers, plate fin heat exchangers such as brazed aluminum plate fins, shell and tube heat exchangers, etc.), direct contact heat exchangers, or some combination of these, shell and tube heat exchangers, spiral, U-shaped, honeycomb, boiler unit (boi ler-cell l), plate shell with etched channels, such as tube in tube or related to any other known type of heat exchanger. The term heat exchanger is broadly meant to be suitable for transferring heat energy or cold from one medium to another, such as any device transferred between at least two different fluids. The term heat exchanger can also refer to any column, column equipment, unit, or other arrangement that provides one or more channels flowing through it and provides direct or indirect heat exchange between one or more refrigerant pipelines and one or more source streams.

[0046] The term "insulated" or "insulating" means (1) including separate insulating material on or within an article or (2) an article that is constructed so that it will act as an insulating material during operation. Insulating material is defined as a material having a thermal conductivity of less than 12 Watts / m-°C (7 Btu / hr-ft-°F). Exemplary insulating materials include mineral fibers (e.g., perlite), rubber, plastic foams (e.g., polyurethane foam, polyvinyl chloride foam, polystyrene foam), fiberglass, vacuum and / or microporous insulation such as aerogel. The term article as used above is meant to refer to any physical object. Exemplary articles include pipes, fluid conduits, and purge vessels. Exemplary insulating articles include pipe-in-pipe constructions having any of the above-mentioned insulating materials in the annular regions between the tubes, hoses made partially of stainless steel wire, polymer films and polymer fabrics, polyurethane foam and rubber, composite pipes made of stainless steel bellows, polypropylene armor, insulation and rubber.

[0047] The term "connected" used herein means that a first element can be directly connected to a second element or indirectly connected to the second element through one or more intermediate elements.

[0048] For ease of description, the present disclosure will be described herein with reference to a gas phase propylene polymerization process, although it will be apparent that the principles upon which the present disclosure is based are applicable to any other exothermic polymerization process in which the polymer recovered after polymerization contains VOCs that need to be purified from the polymer. The present disclosure is suitable for the production and purification of any type of polymer, such as, but not limited to, homopolymers, copolymers, polyolefins, polyethylene, polypropylene, impact copolymers, polystyrene, polyesters, polyurethanes, polysiloxanes, polyacrylates, and the like.

[0049] In a first aspect, the present disclosure relates to a method for producing a polymer, in particular a method for purifying a polymer, comprising the steps of:

[0050] i) in a polymerization reactor in the presence of a catalyst at a first temperature (T 1 ) (also referred to herein as "reaction temperature" or "reactor temperature"), wherein the catalyst has a maximum catalyst capacity that depends on the temperature, and wherein the polymer has a viscosity limit that depends on the temperature;

[0051] ii) discharging polymer from the polymerization reactor into a first process vessel;

[0052] iii) at least partially removing undesirable compounds including volatile organic compounds from the polymer and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a purge gas stream in a first process vessel;

[0053] iv) transferring the polymer from the first process vessel to a second process vessel;

[0054] v) contacting the polymer with a purge gas stream in a second process vessel; and

[0055] vi) recovering the polymer from which the undesirable compounds have been purified;

[0056] Among them, T 1 The catalyst capacity is raised to a maximum and / or the stickiness limit of the polymer to prevent plugging and fouling, and steps ii) to v) are performed while maintaining the polymer at a second temperature (T) of (a) and / or (b). 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 Alternatively, steps ii) to v) are performed while maintaining the polymer at a T below 2 :T 1 +30℃≥T 2 ≥T 1 (or T 1 +20℃≥T 2 ≥T 1 , or T 1 +10℃≥T 2 ≥T 1 ).

[0057] It has been observed that by increasing the reaction temperature in the reactor to the maximum of the catalyst capacity and / or the stickiness limit of the polymer to prevent plugging and fouling, and by maintaining the latent heat of the polymer throughout the following steps ii) to v), preferably using a combination of a heated purge gas medium and high insulation capacity of downstream vessels and pipelines, the odor characteristics of the polymer and the amount of VOC are significantly reduced.

[0058] The polymers may be made according to any known polymerization process, including gas phase processes (such as those conducted in fluidized bed reactors or mechanically stirred bed reactors) and liquid phase processes (such as those conducted in autoclave or tubular reactors).

[0059] Preferably, the polymer is produced using a polymerisation process which takes place in a gas phase reactor, more preferably a fluidised bed reactor.

[0060] In the method according to the disclosure, the manufacture of the polymer is preferably operated under gas phase conditions. The reaction temperature is raised to the maximum value of the catalyst capacity and / or the stickiness limit of the polymer to prevent clogging and fouling, whichever is lower. In the case of a polypropylene impact copolymer manufacturing method operating in the gas phase, the reaction temperature can be in the range of 70°C to 110°C, preferably in the range of 90°C to 100°C. The latent heat of the polymer achieved in this way is then maintained throughout the following steps, preferably by a combination of a heated purge gas medium and high insulation capabilities of downstream containers and pipelines. Alternatively, this heat can be introduced by several mechanical heating processes, in which steam, combustion or electrical heating media are used to heat the polymer in the container, either upstream of the purge container used in the purge process or in the purge container used in the purge process. The method according to the disclosure can be followed by polymer extrusion / granulation.

[0061] The polymer may be maintained at a second temperature (T 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ).

[0062] - providing thermal insulation to at least one location between the polymerization reactor and the second process vessel; and / or

[0063] - injecting hot or superheated steam into the first process vessel; and / or

[0064] - Heating the purge gas.

[0065] Step iii) may be performed as follows:

[0066] - allowing at least some of the undesirable compounds to evaporate from the polymer in the first process vessel and venting the at least some of the undesirable compounds; or

[0067] - contacting the polymer with steam in a first process vessel and evacuating the steam with at least some undesirable compounds from the first process vessel; or

[0068] - contacting the polymer with a purge gas stream in a first process vessel and evacuating the purge gas with at least some undesirable compounds from the first process vessel; or

[0069] - contacting the polymer with a purge gas and steam in a first process vessel and evacuating a mixed stream with at least some undesirable compounds, purge gas and steam from the first process vessel.

[0070] Step iii) can be carried out in the presence of steam, preferably hot steam or superheated steam, and can then be preceded by a drying step.

[0071] Step v) is preferably carried out in the absence of steam in order to recover the dried and purified polymer in step vi).

[0072] In one embodiment, in the first process vessel, a relatively low inert gas flow is introduced. This gas can also be moistened to a point below its water saturation point by adding water or steam to the inert gas stream. Preferably, step iii) utilizes the latent heat of the polymer to prevent significant cooling via the heated inert gas stream to drive any volatile and / or odorous molecules to diffuse from the polymer into the gas stream, which is then discharged to a recovery or destruction system. The introduction of a small amount of moisture also allows the remaining catalyst and / or co-catalyst material to be deactivated in this step. The relatively low flow rate of inert gas allows the polymer to move in a plug flow manner in this step of the method to prevent the material from bypassing (which may have been caused by a fluidized or stirred flow system that is shorter than the normal residence time in the container) to the outlet of the container, and such material may not be fully purified.

[0073] Preferably, in the second process vessel, a relatively high flow rate of heated inert gas (i.e., higher than the flow rate in the first process vessel) is introduced in order to (a) fluidize the fluidized bed of polymer solids, and again (b) prevent cooling of the polymer, so that the diffusion rate of volatile and / or odorous molecules is maximized. The fluidized polymer solids bed is subjected to significantly higher surface renewal and inert gas flow, so that devolatilization of the polymer is maximized.

[0074] The methods according to the present disclosure are applicable to the production and purification of any type of polymer, such as, but not limited to, homopolymers, copolymers, impact copolymers, polyolefins, polyethylene, polypropylene, polystyrene, polyesters, polyurethanes, polysiloxanes, polyacrylates, and the like.

[0075] In a first embodiment of the process, in a polymerization reactor, preferably in a gas phase polymerization reactor, at a first temperature (T 1), preferably at a temperature of at least 70°C (or at least 80°C, or at least 90°C, or at most 95°C, or at most 100°C, or at most 110°C, or at most 120°C). The polymer is then discharged to the first process container through a first transfer line. Undesirable compounds such as volatile organic compounds, odorous compounds and / or residual polymerization reactants are at least partially removed by evaporation under the latent heat of the polymer and emptied through the exhaust gas outlet of the first process container, which can be connected to a recovery system, a waste receiver or a burner. The recovery system generally includes at least one recovery line and an optional separation system such as a fractionation column or a distillation column or a purification column suitable for separating the various components of the exhaust gas, so that some components such as monomers of ethylene or propylene can be purified and reused in the reactor. A vacuum system or a pump can be provided to the exhaust gas outlet for promoting the removal of undesirable compounds. The polymer is then transferred from the first process container to a second process container, where the polymer is contacted with a purge gas stream (preferably nitrogen) to complete the removal of undesirable components. Preferably, the purge gas is introduced into the second process vessel in a countercurrent manner relative to the polymer, and the polymer is introduced into the second process (vessel) in a plug flow manner. Undesirable compounds and purge gas are evacuated through an exhaust outlet of the second process vessel, which exhaust outlet can be connected to a second recovery system, a waste receiver or a burner. A vacuum system or pump can be connected to the exhaust outlet to facilitate the removal of VOCs and / or residual polymerization reactants and purge gas. The polymer is maintained at a second temperature (T) of (a) and / or (b) by (i) providing insulation to at least one location between the polymerization reactor and the second process vessel and / or (ii) by heating the purge gas. 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ). The polymer is thereby purified of undesired compounds and can be used for further processing.

[0076] In a second embodiment of the method, the polymer is manufactured in a polymerization reactor as mentioned above. The polymer is discharged to a first process container through a first transfer line. In the first process container, the polymer is at least partially removed from the undesirable compound by contacting the polymer with a purge gas stream (preferably a hydrocarbon gas such as a C1-C4 hydrocarbon gas, such as ethane, ethylene, propane, or propylene). The undesirable compound is emptied from the first process container through the exhaust gas outlet of the first process container, and the exhaust gas outlet can be connected to a recovery system, a waste receiver, or a burner as mentioned above. A pump or a vacuum system can be connected to the exhaust gas outlet to promote the removal of the purge gas with at least some undesirable compounds. Preferably, the purge gas is introduced into the first process container in a countercurrent manner relative to the polymer, and the polymer is introduced into the first process container in a plug flow manner. The polymer is then transferred from the first process container to the second process container, wherein the polymer is contacted with a purge gas stream (preferably nitrogen) to complete the removal of the undesirable compound. Preferably, the purge gas is introduced into the second process container in a countercurrent manner relative to the polymer, and the polymer is introduced into the second process container in a plug flow manner. The undesirable compounds and the purge gas are evacuated through an exhaust outlet of the second process vessel, which can be connected to a second recovery system, a waste receiver, or a burner. A pump or vacuum system can be connected to the second exhaust outlet to facilitate the removal of undesirable compounds entrained by the purge gas. The polymer is maintained at a second temperature (T) of (a) and / or (b) by (i) providing thermal insulation to at least one location between the polymerization reactor and the second process vessel and / or (ii) heating the purge gas. 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ). The polymer thus purified of undesirable compounds is recovered and can be used for further processing.

[0077] In a third embodiment of the method, the polymer is manufactured in a polymerization reactor as mentioned above. The polymer is then discharged to a first process vessel through a first transfer line. In the first process vessel, undesirable compounds are at least partially removed by contacting the polymer with a hot steam or superheated steam stream. At least some of the undesirable compounds and steam or moisture are evacuated from the first process vessel through the exhaust outlet of the first process vessel, which can be connected to a recovery system, a waste receiver or a burner as already mentioned. A pump or a vacuum system can be connected to the exhaust outlet to facilitate the removal of undesirable compounds and steam. Preferably, steam is introduced into the first process vessel in a countercurrent manner relative to the polymer, and the polymer is introduced into the first process vessel in a plug flow manner. The polymer is then transferred from the first process vessel to a second process vessel, where the polymer is contacted with a purge gas stream (preferably nitrogen) to complete the removal of undesirable compounds. Preferably, purge gas is introduced into the second process vessel in a countercurrent manner relative to the polymer, and the polymer is introduced into the second process (container) in a plug flow manner. The undesirable compounds and purge gas are evacuated through an exhaust outlet of the second process vessel, which can be connected to a second recovery system, a waste receiver, or a burner. A pump or vacuum system can be connected to the exhaust outlet to facilitate the removal of the undesirable compounds and purge gas. The polymer is maintained at a second temperature (T) of (a) and / or (b) by (i) providing thermal insulation to at least one location between the polymerization reactor and the second process vessel and / or (ii) heating the purge gas. 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ). The polymer thus purified of undesirable compounds is recovered and can be used for further processing.

[0078] In a fourth embodiment of the method, the polymer is manufactured in a polymerization reactor as mentioned above. The polymer is then discharged to a first process container through a first transfer line. In the first process container, undesirable compounds are at least partially removed by contacting the polymer with a purge gas stream (preferably a hydrocarbon gas) and a hot steam stream. The purge gas stream and the hot steam stream can be provided simultaneously or separately. Undesirable compounds, purge gas and hot steam are evacuated through the exhaust outlet of the first process container, and the exhaust outlet can be connected to a recovery system, a waste receiver or a burner as mentioned above. A pump or a vacuum system can be connected to the exhaust outlet to promote the removal of undesirable compounds, purge gas and steam. Preferably, steam and purge gas are introduced into the first process container in a countercurrent manner relative to the polymer, and the polymer is introduced into the first process container in a plug flow manner. The polymer is then transferred from the first process container to a second process container, wherein the polymer is contacted with a purge gas stream (preferably nitrogen) to complete the removal of undesirable compounds. Preferably, purge gas is introduced into the second process container in a countercurrent manner relative to the polymer, and the polymer is introduced into the second process (container) in a plug flow manner. The undesirable compounds and purge gas are evacuated through an exhaust outlet of the second process vessel, which can be connected to a second recovery system, a waste receiver, or a burner. A pump or vacuum system can be connected to the exhaust outlet to facilitate the removal of the undesirable compounds and purge gas. The polymer is maintained at a second temperature (T) of (a) and / or (b) by (i) providing thermal insulation to at least one location between the polymerization reactor and the second process vessel and / or (ii) heating the purge gas. 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ). The polymer thus purified of undesirable compounds is recovered and can be used for further processing.

[0079] In a fifth embodiment of the process, the same steps as in the third embodiment of the process are performed, but an additional drying step is performed after contacting the polymer with steam and / or purge gas and before transferring the polymer to the second process vessel. The drying step is performed in the first process vessel, for example by heating and stirring the polymer, or preferably in a dryer arranged between the first process vessel and the second process vessel.

[0080] Any embodiment of the method disclosed above may also include an additional purge step in an additional process container arranged between the first process container and the second process container. It is important that steam or moisture should not be introduced into the second process container in order to provide a dry and purified polymer that can be used for additional processing. A hydrocarbon gas is preferably used as the purge gas in the first process container so that the waste gas leaving the first process container can be easily separated, and the unreacted monomers that are ultimately present in the polymer can be easily recovered, purified, and reused in the reactor. When steam is introduced into the first process container, the recovery system may include any membrane, absorption device, or condensation system to recover water. If a portion of the waste gas of the first process container is recovered and reused in the reactor, it is preferably not used as nitrogen as the purge gas in the first process container to prevent catalyst deactivation in the reactor.

[0081] In any embodiment of the method disclosed above, the flow rate of the purge gas in the second process vessel is preferably higher than the flow rate of the purge gas provided in the first process vessel or the flow rate of any purge gas provided in any process vessel upstream of the second process vessel.

[0082] Advantageously, in any of the embodiments of the method disclosed above, the purge gas is heated to a temperature sufficient to maintain the second temperature (T 2 ) at temperatures (a) and / or (b), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1). Preferably, the purge gas injected into the first purge container comes from a first purge gas source, and the purge gas injected into the second purge container comes from a second purge gas source.

[0083] In a second aspect, the present disclosure is directed to a system for producing a purified polymer, the system comprising:

[0084] - Suitable for a first temperature (T 1 ) and used to produce a polymer reactor;

[0085] a first process vessel configured for at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, comprising a first polymer inlet fluidly connected to the polymerization reactor for receiving the polymer, a first polymer outlet for discharging the polymer having a reduced content of undesirable compounds, a first waste gas outlet for evacuating at least some of the undesirable compounds, and optionally a purge gas inlet for introducing a purge gas;

[0086] a second process vessel configured for purifying the polymer having a reduced content of undesirable compounds, comprising a second polymer inlet fluidly connected to the first process vessel for receiving the polymer having a reduced content of undesirable compounds, a second polymer outlet for discharging the polymer purified of undesirable compounds, a purge gas inlet for introducing a purge gas and a second waste gas outlet for discharging the purge gas with the undesirable compounds purified from the polymer;

[0087] - a first purge gas system configured to introduce a purge gas into a second process vessel;

[0088] - a purified polymer recovery section fluidly connected to the second process vessel;

[0089] wherein the system is configured to maintain the polymer at a second temperature (T ) of (a) and / or (b) while flowing the polymer from the reactor to the second process vessel 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T2 ≤T 1 , or 90℃≤T 2 ≤T 1 ).

[0090] The reactor may be connected to the first process vessel through a first transfer line, the first process vessel may be connected to the second process vessel through a second transfer line, and the second process vessel may be connected to the purified polymer recovery section through a third transfer line.

[0091] In one embodiment or preferred, the system comprises a second purge gas system configured to introduce a purge gas into the first process vessel.

[0092] To maintain the polymer at a second temperature (T) of (a) and / or (b) while flowing the polymer from the reactor to the second process vessel 2 ), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ), the system includes at least one of the following:

[0093] - an isolated portion of the system (not shown) arranged to at least one location between the polymerization reactor and the second process vessel;

[0094] - A heater or heat exchanger is provided for heating the purified gas.

[0095] In one embodiment or preferably, the system comprises a steam injection system configured to introduce hot steam or superheated steam into the first process vessel. Without being bound by any theory, the hot steam can allow for deactivation of some residual catalyst present in the polymer and / or improve degassing of the polymer. The hot steam preferably has a temperature greater than 90°C, preferably greater than or equal to 100°C, and in any embodiment, the hot steam can be superheated steam, for example at a temperature greater than or equal to 100°C or greater than or equal to 110°C. The hot steam participates in achieving the second temperature (T of (a) and / or (b) of maintaining the polymer at 2), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ).

[0096] In one embodiment or preferably, the system further comprises a dryer inserted between the first process container and the second process container and fluidly connected to the first process container and the second process container, and comprising an outlet for draining residual moisture.

[0097] To recover the dry and purified polymer, the steam injection system is not connected to the second process vessel.

[0098] Preferably, the system further comprises a first recovery line connected to a first exhaust gas outlet of the first process container and connected to:

[0099] - waste containers; or

[0100] - a burner; or

[0101] - a reactor; or

[0102] - a separation system configured to separate the steam and / or purge gas introduced into the first process vessel from undesirable compounds; and

[0103] - for the recovery of undesirable compounds separated from the vapours and / or purge gases of the polymerisation reactor;

[0104] - for steam recovery to the steam injection system; and / or

[0105] - for recycling the purified gas to the second purified gas system.

[0106] Preferably, the system comprises a moisture recovery line connected to the steam injection system.

[0107] Preferably, the system further comprises a second waste gas outlet connected to the second process container and a second recovery line connected to:

[0108] - waste containers; or

[0109] - a burner; or

[0110] - a reactor; or

[0111] - a separation system configured to separate the purge gas introduced into the second process vessel from undesirable compounds; and

[0112] - recycling of undesirable compounds separated from the vapours and / or purge gases of the polymerisation reactor; and / or

[0113] - Used to recycle the cleaned gas to the cleaned gas system.

[0114] Preferably, a separation system may be a separation device, such as the separation device described in document WO2018204026 in the name of the applicant and incorporated herein by reference, or any other known gas separation system known in the art. In some embodiments, the system may include at least one temperature monitoring device (not shown) and at least one additional heating device (not shown) arranged in at least one of the first transfer line, the first process container, the second transfer line, the second process container, and the purge gas transmission pipeline system, at least one temperature monitoring device is connected to a temperature controller (not shown), and at least one of the temperature monitoring devices measures a second temperature (T 2 ), at least one additional heating device is operated by the temperature controller to provide heating so that T 2 is (a) and / or (b), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) are 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ).

[0115] The system is suitable for the production and purification of any type of polymers, such as but not limited to homopolymers, copolymers, polyolefins, polyethylene, polypropylene, polystyrene, polyesters, polyurethanes, polysiloxanes, polyacrylates, impact copolymers, etc.

[0116] In some other embodiments, the polymerization reactor can be a stirred tank reactor, a loop reactor, a fluidized bed reactor, a tubular reactor, a tower reactor or an extruder reactor or a combination thereof. It is preferred that the polymerization reactor system is a gas phase polymerization reactor system, preferably including a fluidized bed reactor. In a preferred embodiment of the disclosure, the system is suitable for producing any type of polymer that can be obtained using a gas phase reactor or a fluidized bed reactor.

[0117] Figure 1A first embodiment of a system according to the present disclosure is illustrated in FIG. The system comprises a polymerization reactor 100, a first process vessel 101, a second process vessel 102, a purified polymer recovery section 103, a first purified gas system comprising a purified gas source 142 and a purified gas feed line 107, and a fluid connection with the second process vessel 102. The system may also include a gas recovery system, the gas recovery system comprising a first recovery line 108a for recovering at least some undesirable compounds connected to the first process vessel 101 fluid. After purification and separation, at least one of the purified gas and VOC and / or residual polymerization reactants may flow back to the reactor. Optionally, a separation or purification device may be inserted into the recovery line 108a. A suitable separation device may be, for example, a separation device described in document WO2018204026 under the name of the applicant and incorporated herein by reference, or any other known gas separation system known in the art. The polymerization reactor 100 is fluidly connected to the first process vessel 101 through a first transfer line 104 to withdraw polymer from the polymerization reactor and discharge the polymer to the first process vessel 101 through a first polymer inlet 111 of the process vessel. The first process vessel comprises a first off-gas outlet 112, which may be connected to a first recovery line 108a for evacuating undesirable polymers that are allowed to evaporate in the first process vessel 101. The first process vessel 101 also comprises a first polymer outlet 113 connected to a second transfer line 105 for transferring polymer from the first process vessel 101 to the second process vessel 102 through a second polymer inlet 114 of the second process vessel 102. The second process vessel 102 comprises a purge gas inlet 115, preferably arranged opposite the second polymer inlet 114 and connected to a purge gas feed line 107, for introducing purge gas from a purge gas source 142 into the second process vessel 102. The second process vessel 102 also comprises a second off-gas outlet 116, preferably fluidly connected to a second recovery line 108b, for recovering undesirable compounds and purge gas. The second process vessel 102 also comprises a second polymer outlet 117 opposite to the second polymer inlet 114 and connected to the third transfer line 106 for transferring the polymer purified of VOCs and / or residual polymerization reactants obtained thereby to the purified polymer recovery section 103. Preferably, the second recovery line 108b is connected to a gas separation system 109b, such as the gas separation system described in document WO2018204026 in the name of the applicant and incorporated herein by reference, or any other known gas separation system known in the art.The gas separation system 109b is preferably configured to separate the purge gas from the undesirable compounds and comprises a first portion configured to collect the purge gas and be fluidly connected to the purge gas feed line 107 via a purge gas recycle line 118 for recycling the purge gas and a second portion configured to collect the undesirable compounds and preferably be fluidly connected to the reactor 100 via an undesirable compound recycle line 110. Advantageously, the gas separation system 109b or the undesirable compound recycle line 110 may comprise additional separation and purification means (not shown) for recovering purified monomers that may be reused in the reactor 100. Alternatively, the undesirable compounds and the optional purge gas may be transferred to a waste bin (not shown) or to a burner (not shown). Preferably, in order to maintain the polymer at a second temperature (T) while flowing the polymer from the polymerization reactor to the second process vessel. 2 ), at least one of the first transfer line 104, the first process container 101, the second transfer line 105, and the second process container 102 is isolated, wherein T 2 is (a) and / or (b), where (a) is T 1 -20℃≤T 2 ≤T 1 (or T 1 -15℃≤T 2 ≤T 1 , or T 1 -10℃≤T 2 ≤T 1 , or T 1 -5℃≤T 2 ≤T 1 ) and (b) is 70℃≤T 2 ≤T 1 (or 80℃≤T 2 ≤T 1 , or 90℃≤T 2 ≤T 1 ). Preferably, the system further comprises a heater 119a arranged on the purge gas feed line 107a upstream of the second process container 102, for heating the purge gas.

[0118] Figure 2A second embodiment of a system according to the present disclosure is illustrated in FIG. The system comprises the same elements as described for the first embodiment of the system, and further comprises a second purge gas system comprising a purge gas source 141 and a second purge gas feed line 107b. The first process vessel 101 further comprises a purge gas inlet 120, which is preferably arranged opposite to the first polymer inlet 111 and connected to the purge gas feed line 107b, for introducing the purge gas into the first process vessel 101. The first exhaust gas outlet 112 of the first purge vessel 101 is preferably connected to the first recovery line 108a for evacuating undesirable compounds and purge gas. Undesirable compounds can be separated and purified and some of the recovered monomers can be reused in the reactor. The first recovery line 108a can be fluidly connected to the reactor 100 and a separation or purification device 109a can be inserted in the recovery line 108a. The first recovery line 108a of the first section can be used to recover undesirable compounds, and the second recovery line 108d connected to the separation or purification device and to the purified gas source 141 fluid can be used to recover the purified gas to be reused in the purified gas source 141. Advantageously, the gas separation system 109a or the first recovery line 108a can include additional separation and purification devices (not shown) for recovering purified monomers that can be reused in the reactor 100.

[0119] Preferably, the system further comprises a heater 119 b arranged on the purge gas feed line 107 b upstream of the first process vessel 101 .

[0120] Preferably, the purge gas source 142 supplied to the second purge vessel 102 is a nitrogen source or any other inert gas source, while the purge gas source 141 supplied to the first process vessel 101 is a hydrocarbon gas source.

[0121] Figure 3A third embodiment of a system according to the present disclosure is illustrated in FIG. The system comprises the same elements as described for the first embodiment of the system, and further comprises a steam injection system comprising a steam source or steam generator 143 and a steam feed line 121 connected to a first process vessel 101 fluid. A gas recovery system comprises a recovery line 108a connected to the first process vessel 101 fluid for recovering undesirable compounds and steam. The first process vessel 101 comprises a steam inlet 122 preferably arranged opposite to the first polymer inlet 111 and connected to the steam feed line 121. The first process vessel 101 comprises a first exhaust gas outlet 112 preferably connected to the recovery line 108a for venting undesirable compounds and steam. Preferably, a gas separation system 109a is inserted in the recovery line 108a and is configured to separate moisture from undesirable compounds. The gas separation system 109a comprises a first portion configured to collect moisture and fluidly connected to the steam injection system 143 via a recovery line 124, and a second portion configured to collect undesirable compounds and fluidly connected to the reactor 100 via an undesirable compound recovery line 108a. Advantageously, the gas separation system 109a or the first recovery line 108a may comprise additional separation and purification devices (not shown) for recovering purified monomers that can be reused in the reactor 100. Alternatively, the undesirable compounds and optional moisture may be transferred to a waste bin (not shown) or to a burner (not shown). In this embodiment, the injection of hot steam into the first process vessel 101 participates in maintaining the polymer at a desired temperature level.

[0122] Figure 4 A fourth embodiment of a system according to the present disclosure is illustrated in FIG. The system of the fourth embodiment is different from Figure 3 The third embodiment is that it further comprises a second purge gas system, which comprises a purge gas source 141 and a second purge gas pipeline 107b. The first process vessel 101 comprises a purge gas inlet 120 in addition to the steam inlet 122, both of which are arranged opposite to the first polymer inlet 111. The purge gas inlet 120 is fluidly connected to the second purge gas inlet 107b for introducing the purge gas into the first process vessel 101. The injection of the purge gas through the purge inlet 120 and the injection of the hot steam through the steam inlet 122 can be performed simultaneously or sequentially.

[0123] Figure 5 A fifth embodiment of a system according to the present disclosure is illustrated in FIG. The system of the fifth embodiment comprises a system according to Figure 4The system of the fourth embodiment of the present invention is described with the same elements as those described above, and further includes a dryer 125 inserted between the first process vessel 101 and the second process vessel 102. The dryer 125 preferably includes an inner cylinder 129, the inner cylinder 129 including a dryer polymer inlet 126 for receiving a polymer, a dryer polymer outlet 127 and a dryer exhaust outlet 128. The dryer is preferably arranged with a substantially horizontal axis of the inner cylinder, and preferably includes a motorized shaft (not shown) arranged parallel to or coaxial with the axis of the inner cylinder and including blades configured to stir the polymer and push the polymer toward the dryer polymer outlet 127. The inner cylinder 129 is preferably surrounded by a cylindrical jacket 130 for heating the polymer inside the inner cylinder 125. The heat of the cylindrical jacket 130 can be provided by steam from an auxiliary line 131 extending from the steam feed line 121, and the steam flowing through the cylindrical jacket 130 is evacuated through a steam recovery line 132 fluidly connected to the steam generator 143. Alternatively, the hot steam provided to the cylindrical jacket 130 may come from another hot steam source. Transfer line 105a extends from the first outlet 113 of the first process vessel 101 to the dryer polymer inlet 126 disposed in the inner cylinder 129, and transfer line 105b extends from the dryer polymer outlet 127 to the second polymer inlet 114 of the second process vessel 102. The inner cylinder 129 of the dryer 125 also includes an exhaust gas outlet 128 preferably connected to a recovery line 108e for evacuating moisture from the polymer. The recovery line 108e may be connected to a condenser such as a condenser 108e. Figure 5 108e is fluidly connected to the recovery line 108a shown in FIG. Alternatively, the recovery line 108e can be separated from the recovery line 108a and enter the separation system 109a. Alternatively, the dryer 125 can be heated by an electrical resistance, a heat exchanger, or any other means or devices known to the skilled person.

[0124] Other embodiments of systems according to the present disclosure may include additional process vessels interposed between the first process vessel and the second process vessel.

[0125] In a third aspect, the disclosure relates to a purified polymer obtainable by the method described above, preferably obtained using a system as described above. The purified polymer can be obtained from any type of polymer produced in a polymerization reactor, such as but not limited to homopolymers, copolymers, polyolefins, polyethylene, polypropylene, polystyrene, polyesters, polyurethanes, polysiloxanes, polyacrylates, impact copolymers, and the like.

[0126] An advantage of the disclosure described herein is that the method requires less external heat source to drive the devolatilization of the polymer. The preferred method of introducing heat is via a gas phase reactor (GPR) when used, so as to utilize the polymerization heat of the reaction, rather than an external heat source. The reaction temperature is raised to the maximum value of the catalyst capacity and / or the stickiness limit of the polymer to prevent plugging and fouling, whichever is lower. The reaction temperature can be in the range of 70°C to 110°C, with a preferred range of 90°C to 100°C. The latent heat of the polymer achieved in this manner is then maintained throughout the following steps by a combination of a heated purge gas medium and high insulation capabilities of downstream containers and pipelines. Alternatively, this heat can be introduced by several mechanical heating processes in which steam, combustion or electrical heating media are used to heat the polymer in the container, either upstream of the purge container used in the purge process or within the purge container used in the purge process. Without being bound by any theory, preventing cooling of the polymer in the method allows the diffusion rate of volatile and / or odorous molecules to be maximized when the polymer is contacted with the purge gas.

[0127] In another embodiment of the present disclosure, a method for producing a polymer, in particular a purified polymer, comprises the following steps:

[0128] i) producing a polymer in a polymerization reactor in the presence of a catalyst;

[0129] ii) discharging polymer from the polymerization reactor into a first process vessel;

[0130] iii) at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a purge gas stream in a first process vessel;

[0131] iv) transferring the polymer from the first process vessel to a second process vessel;

[0132] v) contacting the polymer with a purge gas stream in a second process vessel; and

[0133] vi) recovering the polymer from which the undesirable compounds have been purified;

[0134] wherein step iii) comprises flowing the polymer into the first process vessel in plug flow and passing superheated steam to the polymer in countercurrent.

[0135] The latter embodiment of the method may be operated using the third, fourth or fifth embodiment of the system as mentioned above, with or without isolated portions of the system.

[0136] Additional embodiments

[0137] Embodiment 1. A method for producing a polymer, in particular a purified polymer, comprising the following steps: i) in a polymerization reactor in the presence of a catalyst at a first temperature (T 1 ) wherein the catalyst has a maximum catalyst capacity that depends on temperature, and wherein the polymer has a stickiness limit that depends on temperature; ii) discharging the polymer from the polymerization reactor into a first process vessel; iii) at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a first purge gas stream in the first process vessel; iv) transferring the polymer from the first process vessel to a second process vessel; v) contacting the polymer with a second purge gas stream in the second process vessel; and vi) recovering a polymer product comprising the polymer from which the undesirable compounds have been purged; wherein the first temperature is increased to a maximum of the catalyst capacity and / or the stickiness limit of the polymer to prevent plugging and fouling; and wherein steps ii) to v) are operated while maintaining the polymer at a second temperature (T 2 ) so that T 1 -20℃≤T 2 ≤T 1 and / or 70℃≤T 2 ≤T 1 , wherein T in step ii) 2 may be different from T in step v) 2 .

[0138] Embodiment 2. The method according to embodiment 1, wherein the first purge gas stream and the second purge gas stream originate from the same source.

[0139] Embodiment 3. A method according to embodiments 1-2, wherein the polymer is maintained at a temperature T by 2 : providing insulation to at least one location between the polymerization reactor and the second process vessel; and / or injecting hot steam or superheated steam into the first process vessel; and / or heating the first purge gas and / or the second purge gas.

[0140] Embodiment 4. A method according to embodiments 1-3, wherein step iii) is performed by: allowing at least some undesirable compounds to evaporate from the polymer in a first process container and evacuating the at least some undesirable compounds from the first process container; or contacting the polymer with steam or superheated steam in the first process container and evacuating the steam with at least some undesirable compounds from the first process container; or contacting the polymer with a first purge gas stream in the first process container and evacuating the first purge gas with at least some undesirable compounds from the first process container; or contacting the polymer with a first purge gas stream and steam in the first process container and evacuating a mixed stream with at least some undesirable compounds from the first process container.

[0141] Embodiment 5. The process of any of embodiments 1 to 4, wherein step iii) is carried out in the presence of steam or superheated steam and then an additional drying step is carried out before step v).

[0142] Embodiment 6. The method of any one of Embodiments 1-5, wherein step v) is performed in the absence of steam.

[0143] Embodiment 7. A system for producing a purified polymer, comprising: a polymerization reactor suitable for operating at a first temperature and for producing a polymer; a first process vessel configured to at least partially remove undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, the first process vessel comprising a first polymer inlet (111) fluidly connected to the polymerization reactor (100) for receiving the polymer, a first polymer outlet (113) for discharging the polymer having a reduced content of undesirable compounds, a first exhaust outlet (112) for evacuating at least some of the undesirable compounds, and optionally a first purge gas inlet (120) for introducing a first purge gas; a second process vessel configured to purify the polymer having a reduced content of undesirable compounds; A process vessel (102) comprising a second polymer inlet (114) fluidly connected to the first process vessel (101) for receiving a polymer having a reduced content of undesirable compounds, a second polymer outlet (117) for discharging the polymer purified of undesirable compounds, a second purge gas inlet (115) for introducing a second purge gas, and a second exhaust gas outlet (116) for discharging the second purge gas with undesirable compounds purified from the polymer; a purge gas system (142, 107) configured to introduce the second purge gas into the second process vessel (102); a purified polymer recovery section (103) fluidly connected to the second process vessel (102); wherein the system is configured to maintain the polymer at a second temperature (T ) while flowing the polymer from the polymerization reactor to the second process vessel 2 ) so that T1 -20℃≤T 2 ≤T 1 and / or 70℃≤T 2 ≤T 1 .

[0144] Embodiment 8. The system of Embodiment 7, wherein the first purge gas and the second purge gas originate from the same source.

[0145] Embodiment 9. The system of Embodiments 7-8, wherein the purge gas system is a second purge gas system, and wherein the system further comprises a first purge gas system configured to introduce the first purge gas into the first process vessel.

[0146] Embodiment 10. A system according to embodiments 7-9, comprising at least one of: an isolated portion of the system arranged at at least one position between the polymerization reactor (100) and the second process vessel (102), and / or; a heater (119) or a heat exchanger (50) configured for heating the first purge gas and / or the second purge gas.

[0147] Embodiment 11. The system according to any one of Embodiments 7 to 10, further comprising a steam injection system (143, 121) configured to introduce hot steam or superheated steam into the first process vessel (101).

[0148] Embodiment 12. The system according to any one of Embodiments 7 to 11 further comprises a dryer (125), which is inserted between the first process container (101) and the second process container (102) and is fluidly connected to the first process container (101) and the second process container (102), and comprises a dryer exhaust gas outlet (128) for exhausting residual moisture.

[0149] Embodiment 13. The system according to embodiments 7-12 also includes a first exhaust gas outlet (112) connected to the first process container (101) and a first recovery pipeline (108a) connected to the following: a waste container; or a burner; or a reactor (100); or a separation system (109a), wherein the separation system (109a) is configured to separate the steam and / or the first purge gas introduced into the first process container from undesirable compounds, and: for recovering undesirable compounds separated from the steam and / or the first purge gas of the polymerization reactor (100); for recovering the steam to the steam injection system (143, 121); and / or for recovering the first purge gas to the purge gas system (141, 123).

[0150] Embodiment 14. The system according to embodiments 7-13 also includes a second exhaust gas outlet (116) connected to the second process container (102) and a second recovery pipeline (108b) connected to the following: a waste container; or a burner; or a reactor (100); or a separation system (109b), which is configured to separate the second purge gas introduced into the second process container from undesirable compounds, and is used to: recover undesirable compounds separated from the steam and / or the second purge gas of the polymerization reactor (100); and / or for recycling the second purge gas to a second purge gas system.

[0151] Embodiment 15. The system according to embodiment 14, wherein at least one temperature monitoring device and at least one additional heating device are additionally arranged at at least one location on the first purified gas feed line and / or the second purified gas feed line.

[0152] Embodiment 16. The system according to any one of embodiments 7 to 15, further comprising at least one temperature monitoring device and at least one additional heating device arranged at at least one position between the polymerization reactor and the second process vessel, the at least one temperature monitoring device being in communication with the temperature controller, and the at least one additional heating device being operated by the temperature controller to provide heating to maintain T 2 .

[0153] Embodiment 17. A system according to any one of embodiments 7 to 13, wherein the polymerization reactor (100) is a gas phase reactor and comprises a recovery line (40) for recovering heated unreacted monomers, which recovery line is in contact with at least one heat exchanger (50) to remove heat from the unreacted monomers.

[0154] Embodiment 18. A clarification polymer obtainable by the process of embodiments 1 to 6, having an odor profile ranging from imperceptible to clearly perceptible but not annoying, measured according to method VDA 270.

[0155] Embodiment 19. A method for producing a polymer, in particular a purified polymer, comprising the following steps: i) producing a polymer in a polymerization reactor in the presence of a catalyst; ii) discharging the polymer from the polymerization reactor into a first process vessel; iii) at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a first purified gas stream in the first process vessel; iv) transferring the polymer from the first process vessel to a second process vessel; v) contacting the polymer with the first purified gas stream in the second process vessel; and vi) recovering the polymer from which the undesirable compounds have been purified; wherein step iii) comprises causing the polymer to flow into the first process vessel in a plug flow manner and sending superheated steam to the polymer in a countercurrent manner.

[0156] In order to promote a better understanding of the embodiments of the present disclosure, the following examples of preferred or representative embodiments are given. The following examples should not be construed in any way as limiting or defining the scope of the present disclosure.

[0157] Example

[0158] The comparative impact copolymer has been prepared by a gas phase polymerization process in a gas phase polymerization reactor under standard conditions at a temperature in the reactor of 85° C., well below the catalyst capacity limit and / or the stickiness limit of the polymer to prevent plugging and fouling. The impact copolymer thus obtained was purified under standard conditions under a nitrogen stream.

[0159] Comparative samples of the impact copolymers produced under the above conditions were tested for odor characteristics according to method VDA 270 published by the Automobile Industry Association VDA (Verband der Automobi leindus tr ie). The method is based on the odor evaluation rating of the prepared samples tested by at least three individual testers. The odor evaluation rating includes six levels:

[0160] -Level 1: Imperceptible;

[0161] -Level 2: Noticeable, but not disturbing;

[0162] - Level 3: Clearly perceptible but not disturbing;

[0163] -Level 4; Annoying;

[0164] -Level 5; Strongly disturbing; and

[0165] -Level 6: Unacceptable.

[0166] After decontamination under standard conditions, the comparative impact copolymer was rated at an odor level of 4.1, ie, the odor was bothersome.

[0167] The total volatile organic pollutants (TVOC) of the control samples were measured according to the VDA277 method, and the average TVOC content was 113 ppm.

[0168] Other comparative impact copolymer samples were prepared and purged by varying the purge gas flow conditions of the steam flow, but none of these purge conditions provided a purified impact copolymer having a TVOC less than 99 ppm as measured according to the VDA 277 method.

[0169] The impact copolymer according to the disclosure has been prepared by a gas phase polymerization process in a gas phase polymerization reactor, but the temperature of the reactor was increased to 90° C. (i.e. closer to the catalyst capacity limit and the stickiness limit of the polymer to prevent plugging and fouling). The impact copolymer thus obtained was purified under standard conditions under a nitrogen stream. The increase in temperature in the reactor provided an impact copolymer according to the disclosure with a reduced odor level of 3.6 (i.e. between clearly perceptible but not annoying and annoying), and a TVOC content of 87 ppm measured according to the VDA 277 method, i.e. a 23% reduction in TVOC when the reactor temperature was increased by only 5° C. while the purging conditions remained unchanged.

[0170] One or more illustrative embodiments of the disclosure embodiments disclosed herein are proposed herein. For the sake of clarity, all features of physical realization are not described or shown in this application. It should be understood that in the development of the physical embodiment of the embodiment incorporated into the present disclosure, in order to achieve the developer's goal, many specific decisions of realization must be made, such as complying with system-related, business-related, government-related and other constraints, which change from time to time with realization. Although the developer's efforts may be time-consuming, such efforts are routine tasks for those of ordinary skill in the art who benefit from the present disclosure.

[0171] Unless otherwise indicated, all numerical values ​​used in this specification and the related claims expressing the amounts of ingredients, properties such as molecular weight, reaction conditions, etc. should be understood as being modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters listed in the following specification and the attached claims are approximate values, which may vary depending on the desired properties typically sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0172] Therefore, the present disclosure is well suited to obtain the results and advantages mentioned and inherent therein. The specific embodiments and configurations disclosed above are illustrative only, because it is obvious that different but equivalent means can be adopted to modify and implement the present disclosure for those skilled in the art who benefit from the teachings herein. In addition, except as described in the following claims, it is not intended to limit the details of the construction or design shown herein. It is therefore obvious that the specific illustrative embodiments disclosed above can be changed, combined or modified, and all such changes are considered to be within the scope and spirit of the present disclosure. In the absence of any element not specifically disclosed herein and / or any optional element disclosed herein, the disclosure disclosed illustratively herein can be appropriately implemented. Although compositions and methods are described in terms of "comprising", "containing" or "including" various components or steps, the compositions and methods can also be "essentially composed of various components and steps" or "composed of various components and steps". All numerical values ​​and ranges disclosed above can be changed to a certain extent. Whenever a numerical range with a lower limit and an upper limit is disclosed, any numerical value and any included range falling within the range are specifically disclosed. In particular, each range of values ​​disclosed herein (having the following format "from about a to about b", or equivalently "from about a to b", or equivalently "from about ab") should be understood to recite each value and range included in the broader range of values. In addition, the terms in the claims have their ordinary, general meaning unless otherwise explicitly and clearly defined by the patentee. In addition, the indefinite articles "a" or "an" as used in the claims are defined herein to mean one or more than one of the elements it introduces.

Claims

1. A method for producing a polymer, in particular for purifying a polymer, comprising the following steps: i) producing a polymer in a polymerization reactor in the presence of a catalyst at a first temperature (T1), wherein the catalyst has a maximum catalyst capacity that is temperature dependent, and wherein the polymer has a temperature dependent adhesion limit; ii) discharging polymer from the polymerization reactor into a first process vessel; iii) at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a first purified gas stream in a first process vessel; iv) transferring the polymer from the first process vessel to a second process vessel; v) contacting the polymer with a second purge gas stream in a second process vessel; and vi) recovering a polymer product comprising the polymer from which undesirable compounds have been purified; wherein the first temperature is increased to a maximum of the catalyst capacity and / or a stickiness limit of the polymer to prevent plugging and fouling; and Wherein steps ii) to v) are operated while maintaining the polymer at a second temperature (T2) such that T1-20°C≤T2≤T1 and / or 70°C≤T2≤T1, wherein T2 of step ii) may be different from T2 of step v).

2. The method of claim 1, wherein the polymer is maintained at temperature T2 by: Providing thermal insulation to at least one location between the polymerization reactor and the second process vessel; and / or injecting hot or superheated steam into the first process vessel; and / or The first purge gas and / or the second purge gas are heated.

3. The method according to any preceding claim, wherein step iii) is performed by: allowing at least some of the undesirable compounds to evaporate from the polymer in the first process vessel and evacuating the at least some of the undesirable compounds from the first process vessel; or contacting the polymer with steam or superheated steam in a first process vessel and evacuating the steam with at least some undesirable compounds from the first process vessel; or contacting the polymer with a first purge gas stream in a first process vessel and evacuating the first purge gas with at least some undesirable compounds from the first process vessel; or The polymer is contacted with a first purge gas stream and steam in a first process vessel and a mixed stream with at least some undesirable compounds is evacuated from the first process vessel.

4. A process according to any preceding claim, wherein step iii) is carried out in the presence of steam or superheated steam and then an additional drying step is carried out before step v).

5. A process according to any preceding claim, wherein step v) is carried out in the absence of steam.

6. Clarifying polymer obtainable by the process according to any of claims 1 to 5, having an odor profile ranging from imperceptible to clearly perceptible but not annoying, measured according to method VDA 270.

7. A system for producing a purified polymer, comprising: a polymerization reactor suitable for operating at a first temperature (T1) and for producing a polymer; a first process vessel configured for at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from a polymer, the first process vessel comprising a first polymer inlet fluidly connected to the polymerization reactor for receiving the polymer, a first polymer outlet for discharging the polymer having a reduced content of the undesirable compounds, a first waste gas outlet for venting at least some of the undesirable compounds, and optionally a first purge gas inlet for introducing a first purge gas; a second process vessel configured for purifying the polymer having a reduced content of undesirable compounds, comprising a second polymer inlet fluidly connected to the first process vessel for receiving the polymer having a reduced content of undesirable compounds, a second polymer outlet for discharging a polymer product comprising the polymer from which the undesirable compounds have been purified, a second purge gas inlet for introducing a second purge gas, and a second waste gas outlet for discharging the second purge gas with the undesirable compounds purified from the polymer; a purge gas system configured to introduce a second purge gas into the second process vessel; a purified polymer recovery section fluidly connected to the second process vessel; Wherein the system is configured to maintain the polymer at a second temperature (T2) when flowing the polymer from the polymerization reactor to the second process vessel, such that T1-20°C≤T2≤T1 and / or 70°C≤T2≤T1.

8. The system of claim 7, wherein the purge gas system is a second purge gas system, and wherein the system further comprises a first purge gas system configured to introduce the first purge gas into the first process vessel.

9. The system according to claim 7 or 8, comprising at least one of the following: an isolated portion of the system disposed at at least one location between the polymerization reactor and the second process vessel; and / or A heater or heat exchanger is configured to heat the first purge gas and / or the second purge gas.

10. The system of claims 7-9, further comprising a steam injection system configured to introduce hot steam or superheated steam into the first process vessel.

11. The system of claims 7-10, further comprising a dryer interposed between the first process vessel and the second process vessel and fluidly connected to the first process vessel and the second process vessel, and comprising a dryer exhaust outlet for evacuating residual moisture.

12. The system of claims 7-11, further comprising a first recovery line connected to the first exhaust outlet of the first process vessel and connected to at least one of: waste containers; or burner; or reactor; or a separation system configured to separate the steam and / or the first purge gas introduced into the first process vessel from undesirable compounds, and for recovering undesirable compounds separated from the steam and / or the first purge gas of the polymerization reactor; For steam recovery to the steam injection system; and / or Used to recover the first purified gas to the first purified gas system.

13. The system of claims 7-12, further comprising a second recovery line connected to a second exhaust outlet of the second process vessel and connected to: waste containers; or burner; or reactor; or A separation system configured to separate the second purge gas introduced into the second process vessel from the undesirable compounds and to Recovering undesirable compounds separated from the polymerization reactor steam and / or the second purge gas; and / or Used to recover the second purified gas to the second purified gas system.

14. The system according to claims 7-13, further comprising at least one temperature monitoring device and at least one additional heating device arranged at at least one position between the polymerization reactor and the second process vessel, the at least one temperature monitoring device being in communication with the temperature controller, and the at least one additional heating device being operated by the temperature controller to provide heating to maintain T2.

15. The system of claim 14, wherein at least one temperature monitoring device and at least one additional heating device are additionally arranged at at least one location on the first purge gas feed line and / or the second purge gas feed line.

16. The system of claims 7-15, wherein the polymerization reactor is a gas phase reactor and comprises a recovery line for recovering heated unreacted monomers, the recovery line being in contact with at least one heat exchanger to remove heat from the unreacted monomers.

17. Clarifying polymer obtainable by the process according to any of claims 7 to 16, having an odor profile ranging from imperceptible to clearly perceptible but not annoying, measured according to method VDA 270.

18. A method for producing a polymer, in particular for purifying a polymer, comprising the steps of: i) producing a polymer in a polymerization reactor in the presence of a catalyst; ii) discharging polymer from the polymerization reactor into a first process vessel; iii) at least partially removing undesirable compounds including volatile organic compounds and / or residual polymerization reactants and / or odorous compounds from the polymer, and optionally contacting the polymer with a first purified gas stream in a first process vessel; iv) transferring the polymer from the first process vessel to a second process vessel; v) contacting the polymer with a second purge gas stream in a second process vessel; and vi) recovering a polymer product comprising the polymer from which undesirable compounds have been purified; wherein step iii) comprises flowing the polymer into the first process vessel in plug flow and passing superheated steam to the polymer in countercurrent.

Images