Abstract: The present disclosure relates to methods for controlling gas phase polymerization reactors. A method for controlling a fluidized bed reactor can include forming a fluidized bed in a reactor followed by discharge of polymer product from the reactor to a product discharge tank. The polymer product can then be discharged from the product discharge tank to a blow tank and the pressure of the blow tank is measured. The pressure measured in the blow tank can then be used to control the reactor by changing one or more reactor operating inputs based on the measured blow tank pressure.

Abstract: Methods for producing polyolefin polymers may use a predictive melt index regression to estimate the melt index of the polyolefin during production based on the composition of the gas phase and, optionally, the concentration of catalyst in the reactor or reactor operating conditions. Such predictive melt index regression may include multiple terms to account for concentration of ICA in the reactor, optionally concentration of hydrogen in the reactor, optionally concentration of comonomer in the reactor, optionally the catalyst composition, and optionally reactor operating conditions. One or more terms may independently be represented by a smoothing function that incorporates a time constant.

Abstract: The present invention relates to a process for determining a set of one or more operating conditions of an olefin polymerization reactor for the synthesis of a polyolefin in slurry condition, comprising the steps of: a1) introducing a polyolefin into a volume of at least one diluent, said diluent being agitated by a powered agitator at a first temperature T1; b1) monitoring the power consumed by the agitator as a function of the concentration, for at least three concentrations C1, C2, and Cn, which are different from each other; c1) repeating steps a1) and b1) at two or more subsequent temperatures T2 and Tn, which are different from each other and from T1; d1) determining from the power consumed by the agitator as a function of concentration, said set of one or more stable operating conditions for the synthesis of the polyolefin in the olefin polymerization reactor.

Abstract: A nitrogen generation system includes a heat exchanger for receiving supply air and cooling air and providing temperature conditioned supply air, a flow control valve for controlling a flow of the cooling air through the heat exchanger, and an air separation module for receiving the temperature conditioned supply air and generating nitrogen-enriched air. The nitrogen generation system also includes a sensor for measuring a parameter of the nitrogen-enriched air selected from the group consisting of a temperature, a flow rate, an oxygen concentration, and combinations thereof, and a controller connected to the sensor and the flow control valve for controlling the flow of the cooling air through the heat exchanger based on the parameter of the nitrogen-enriched air measured by the sensor.

Abstract: A process comprises polymerizing an olefin monomer in a loop reactor in the presence of a catalyst and a diluent, and producing a slurry comprising solid particulate olefin polymer and diluent. The Biot number is maintained at or below about 3.0 within the loop reactor during the polymerizing process. The slurry in the loop reactor forms a slurry film having a film coefficient along an inner surface of the reactor wall, and the film coefficient is less than about 500 BTU·hr?1·ft?2·° F.?1.

Abstract: A process for polymerizing or copolymerizing ethylenically unsaturated monomers in the presence of free-radical polymerization initiators, wherein the polymerization is carried out at temperatures from 100° C. to 350° C. and pressures in the range of from 110 MPa to 500 MPa in a continuously operated polymerization reactor which is controlled by a pressure control valve at the outlet of the polymerization reactor, the process comprising continuously monitoring the pressure within the polymerization reactor, feeding a pressure signal to a controller for controlling the control valve and having the controller altering the opening of the pressure control valve to control the pressure within the polymerization reactor, wherein the controller starts an emergency shutdown program when the pressure control valve closes more than a preset threshold value and the pressure within the polymerization reactor decreases below a preset pressure threshold.

Abstract: A system including a vessel with at least two fluid inlets and a fluid outlet wherein one fluid inlet is positioned higher in the vessel than the other fluid inlet is provided. The fluid inlets may be connected to a polymerization reactor and each fluid inlet may be configured to deliver fluid to the vessel from a different zone of the polymerization reactor. During shut-down of a polymerization reactor, reaction mixture is discharged to a separation system where polymer particles are removed from the mixture prior to being released into the atmosphere.

Abstract: A process comprises polymerizing an olefin monomer in a loop reactor in the presence of a catalyst and a diluent, and producing a slurry comprising solid particulate olefin polymer and diluent. The Biot number is maintained at or below about 3.0 within the loop reactor during the polymerizing process. The slurry in the loop reactor forms a slurry film having a film coefficient along an inner surface of the reactor wall, and the film coefficient is less than about 500 BTU·hr?1·ft?2·° F.?1.

Abstract: A method of producing an ?-olefin low polymer, wherein an ?-olefin is subjected to low polymerization in a solvent in the presence of a chromium catalyst and at least one inert gas. The proportion of the inert gas is maintained from 0.010 to 50.00% by volume in a gas phase part of a reactor, such that inert gas is discharged from the reactor and/or circulation piping when the proportion exceeds 50.00%. The chromium catalyst contains a chromium compound, at least one nitrogen-containing compound, an aluminum-containing compound, and optionally a halogen-containing compound. Unreacted ?-olefin and solvent separated from a reaction liquid are circulated back into the reactor.

Abstract: Disclosed herein are methods for controlling bubble formation in a polymerization reactor. The method includes: (a) determining a concentration of at least one component at a location in the reactor using a mathematical model; (b) determining a vapor pressure of the composition based at least in part upon the concentration of the component; (c) determining an operating pressure of the reactor at the location; (d) determining a pressure difference as ?P=PX?PV, wherein PX is the operating pressure and PV is the vapor pressure; (e) comparing the ?P to a threshold value; and (f) implementing an effect when the ?P is less than the threshold value.

Abstract: A gas-phase polyolefin reactor system for rapidly transitioning from one polyolefin product to another is disclosed. The reactor system comprises a control valve, a high-flow valve, a polyolefin reactor, a flow meter, a totalizer and an empirical model. During a transition, the empirical model predicts a required amount based upon an initial concentration and a selected ending concentration, the flow meter measures a flow rate, the totalizer determines a totalized amount when the flow rate of the first stream reaches the required amount based upon the measured flow rate and outputs the totalized amount to the empirical model, and the empirical model compares the required amount to the totalized amount and determines a transition endpoint. A method of rapidly transitioning the reactor system from one polyolefin product to another is also disclosed.

Abstract: Process for the preparation of etherified melamine/formaldehyde condensates, in which first a methylolation of melamine with a formaldehyde component in the molar ratio of from 1:6 to 1:15, preferably at a pH of >7, is carried out. This is followed by an etherification of the resulting hydroxymethylation intermediate in the presence of a C1-C20-alkyl, preferably of a C1-C6-alcohol, particularly preferably of a C1-C4-alcohol, at a pH of <4.5, and subsequently by at least one distillation step in order to remove in particular methanol from the system, the pH of >9.5 being established before, during and/or after the distillation. According to the invention, a plurality of hydroxymethylation, etherification and distillation steps follow in order to achieve an etherified melamine/formaldehyde condensate which is distinguished by a high degree of hydroxymethylation, a high solids content and a low viscosity.

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

Abstract: Methods for controlling the weight ratio of a higher molecular weight component to a lower molecular weight component of an olefin polymer are disclosed. This weight ratio can be increased as polymerization reaction temperature and/or catalyst system residence time are increased.

Abstract: A control method for controlling a fluidized bed polymerization reactor in the production of a given polymer product, the method comprising the following steps: (a) determining a ratio of the production rate of the polymer product in the reactor to the pressure in the reactor, (b) setting a production rate of the polymer product in the reactor which production rate, on the basis of said ratio of step (a), corresponds to a desired pressure in the reactor; (c) adjusting the feed rates of monomers into the reactor in accordance with said set point production rate.

Abstract: A procedure for improved temperature control in controlled radical polymerization processes is disclosed. The procedure is directed at controlling the concentration of the persistent radical in ATRP and NMP polymerizations procedures and the concentration of radicals in a RAFT polymerization process by feeding a reducing agent or radical precursor continuously or intermittently to the reaction medium through one of more ports.

Abstract: The present invention relates to production of polymer, and in particular provides an interlock for use in a process for production of a polymer in a reactor, which process comprises: a. polymerising a monomer and optionally a comonomer in the reactor to produce polymer, optionally in the presence of an inert hydrocarbon, and b. withdrawing produced polymer from the reactor, said interlock being based on the temperature in the reactor, and comprising: 1. measuring the temperature in the reactor or a temperature representative of the temperature in the reactor, and 2. comparing said measured temperature to a threshold temperature, said interlock being characterized in that withdrawal is allowed if the measured temperature is greater than the threshold temperature but is prevented if the measured temperature is lower than the threshold temperature.

Abstract: Interlock for use in a process for degassing of a polymer powder in a degassing vessel. The interlock includes the steps of 1. measuring the temperature of the polymer powder within or exiting the degassing vessel, 2. comparing the measurement value to a threshold value in order to ascertain whether it is lower than the threshold value or not, and 3. if the measured temperature is lower than the threshold value taking one or more actions to reduce the concentration of hydrocarbons in the polymer powder exiting the degassing vessel and/or to stop the polymer powder withdrawal from that degassing vessel.

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

Abstract: A system and method for discharging a transfer slurry from a first polymerization reactor through a transfer line to a second polymerization reactor, the transfer slurry including at least diluent and a first polyethylene. A product slurry is discharged from the second polymerization reactor, the product slurry including at least diluent, the first polyethylene, and a second polyethylene. The velocity, pressure drop, or pressure loss due to friction in the transfer line is determined, and a process variable adjusted in response to the velocity, pressure drop, or pressure loss not satisfying a specified value.

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

Abstract: Methods for removing polymer skins or build-up from reactor walls in polymerization reactor systems containing a loop slurry reactor are disclosed. Such methods can employ removing some or all of the comonomer from the reactor system in combination with increasing the polymerization temperature of the loop slurry reactor.

Abstract: Generally, a method of monitoring a polymerization reaction in a fluid bed reactor to generate, in on-line fashion, data indicative of the imminent occurrence of a discontinuity event (for example, sheeting) and optionally also control the reaction to prevent the occurrence of the discontinuity event is provided. Typical embodiments include the steps of generating in on-line fashion at least one of bed static data indicative of static charge in the fluidized bed and carryover static data indicative of carryover static; and generating at least one of temperature data (in on-line fashion using at least one monitored reaction parameter) indicative of a first temperature and acoustic emission data indicative of resin stickiness in the reactor, where the first temperature is indicative of at least one of degree of resin stickiness in the reactor and a characteristic of melting behavior of polymer resin in the reactor in the presence of at least one diluent.

Abstract: Provided is a method for performing a polymerization process in a stirred reactor, wherein a critical time window is determined by means of a monitor of at least one polymerization process parameter and an associated process window, and when a critical time window is present, an adaptation of process conditions is made in order to configure the polymerization process to conform to the process window.

Abstract: The present invention relates to the degassing of polymer powder, and in particular to an interlock for use in a process for degassing of a polymer powder in a degassing vessel, which interlock comprises: 1. measuring the temperature of the polymer powder within or exiting the degassing vessel, 2. comparing said measurement value to a threshold value in order to ascertain whether it is lower than the threshold value or not, and 3. if the measured temperature is lower than the threshold value taking one or more actions to reduce the concentration of hydrocarbons in the polymer powder exiting the degassing vessel and/or to stop the polymer powder withdrawal from that degassing vessel.

Abstract: The present invention relates to production of polymer, and in particular provides an interlock for use in a process for production of a polymer in a reactor, which process comprises: a. polymerising a monomer and optionally a comonomer in the reactor to produce polymer, optionally in the presence of an inert hydrocarbon, and b. withdrawing produced polymer from the reactor, said interlock being based on the temperature in the reactor, and comprising: 1. measuring the temperature in the reactor or a temperature representative of the temperature in the reactor, and 2. comparing said measured temperature to a threshold temperature, said interlock being characterised in that withdrawal is allowed if the measured temperature is greater than the threshold temperature but is prevented if the measured temperature is lower than the threshold temperature.

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

Abstract: This invention is related to the field of olefin polymerisation in double loop reactors and especially to the polymerisation of olefins with very active catalyst systems. It discloses a method for reducing blockage when transferring polymer product from the first loop to the second loop of a double loop reactor.

Abstract: In some embodiments, a method including the steps of monitoring a polymerization reaction which produces a polymer resin in a fluid bed reactor, where a dry melt reference temperature is characteristic of melting behavior of a dry version of the resin, and in response to data indicative of at least one monitored parameter of the reaction, determining in on-line fashion a reduced melt reference temperature that is at least substantially equal to the difference between the dry melt reference temperature and a temperature by which the dry melt reference temperature is depressed by the presence of condensable diluent gas with the resin in the reactor. Optionally, the method also includes the step of controlling the reaction in response to the reduced melt reference temperature or a stickiness parameter determined from the reduced melt reference temperature.

Abstract: The present invention relates to a method for performing a polymerization process in a stirred reactor, wherein a critical time window is determined by means of a monitor of at least one polymerization process parameter and an associated process window, and when a critical time window is present, an adaptation of process conditions is made in order to configure the polymerization process to conform to the process window.

Abstract: In a process for producing water-absorbing polymeric particles which comprises generating droplets comprising monomers, polymerizing the monomers in a heated gas phase surrounding the droplets and flowing the gas through the polymerization reactor, the temperature of the gas leaving the polymerization reactor is closed-loop controlled.

Abstract: A method for ethylene slurry polymerisations in a loop reactor in the presence of ethylene monomer, diluent and catalyst and optionally co-monomer and hydrogen, wherein the polymerisation temperature is maintained below the swelling temperature, characterised in that the swelling temperature is calculated as a function of co-monomer concentration and the number average molecular weight of the polyethylene end-product.

Abstract: A control method for controlling a fluidized bed polymerisation reactor in the production of a given polymer product, the method comprising the following steps: (a) determining a ratio of the production rate of the polymer product in the reactor to the pressure in the reactor, (b) setting a production rate of the polymer product in the reactor which production rate, on the basis of said ratio of step (a), corresponds to a desired pressure in the reactor; (c) adjusting the feed rates of monomers into the reactor in accordance with said set point production rate.

Abstract: A process for preparing polymer dispersions stabilized by polyvinyl alcohol includes a step of emulsion polymerization. The polymerization occurs such that at least 60% of the total conversion occurs at a temperature from 100° C. to 140° C.

Abstract: The present invention provides a novel one-step process for preparing an aqueous polymer dispersion by the free radical aqueous emulsion polymerization comprising mixing at least water, a dispersant, and an oil-soluble initiator; raising a temperature from the starting to the end reaction temperature while metering at least ethylenically unsaturated monomers and a water-soluble initiator into a reaction vessel, conducting polymerization of the monomers in the presence of the water-soluble initiator at a temperature up to the end reaction temperature, and when the temperature has reached the end reaction temperature, conducting polymerization by the oil-soluble initiator. The oil-soluble initiator is inactive at the starting reaction temperature and becomes more active as a temperature approaches the end reaction temperature at which the oil-soluble initiator is fully active.

Abstract: To provide a method for producing a polymer for semiconductor lithography which can attain high uniformity in the polymer from lot to lot. The method for producing a polymer for semiconductor lithography includes the step (P) of heating a polymerizable monomer and a polymerization initiator in a solvent, to thereby polymerize the monomer, the step (P) having the step of controlling a polymerization pressure by regulating a liquid level in a container (WO) which is disposed between a polymerization tank and the atmospheric air and which provides liquid sealing.

Abstract: A continuous polymerization apparatus is provided for producing an amphoteric electrolyte resin by continuous bulk polymerization at low cost, which apparatus includes a reaction vessel, the reaction vessel including at least four polymerization zones adjacent to each other in series, each polymerization zone being separated by a partition plate, the partition plates admitting a stirring shaft with stirrers, each of the polymerization zones having a thermosensor for sensing temperature within the polymerization zone, a heating device for heating the polymerization zone and a cooling device for cooling the polymerization zone.

Abstract: A method for controlling a solution process for the polymerisation of olefins is disclosed. The method is based on an algorithm that calculates predicted operating parameters of the process, including calculation of the extent of reaction (?), as a function of the solution density (?), and then calculation of the whole composition of the solution. The algorithm resolves a system of equations comprising the equation of state in the PC-SAFT form, the Lewis-Mayo equation for monomer incorporation into a copolymer, and the stoichiometry equation. Predicted parameters are compared to target parameters to detect possible deviations and implement corresponding compensation in the feed.

Abstract: Provided is a method for monitoring a polymerization reaction in a fluid bed reactor to determine in on-line fashion a current value, and preferably also a limiting value, of a stickiness control temperature, and optionally controlling the reaction in response thereto in an effort to prevent occurrence of a discontinuity event. The stickiness control temperature is a temperature indicative of a characteristic of melting behavior of polymer resin in the reactor, and may be indicative of occurrence of resin sheeting or another discontinuity event. Optionally , a predetermined relation between values of acoustic energy in the reactor and values of a stickiness control temperature in used to provide error checking for determination of the stickiness control temperature, or a current value of the stickiness control temperature is determined from acoustic data and a predetermined relation between values of an acoustic condition in the reactor and values of the stickiness control temperature.

Abstract: Methods for polymerization of an olefin monomer and polymers formed therefrom are described herein.

Abstract: A process for producing an amphoteric electrolyte resin by continuous bulk polymerization at low cost is provided. Also provided is an apparatus for achieving the process. The process comprises the steps of: feeding, from the mixture supply side, a mixture comprising 0.01 to 10 wt % of at least one radically polymerizable basic monomer containing a nitrogen atom, 0.01 to 35 wt % of at least one radically polymerizable acidic monomer having a carboxyl group and 45 to 99.98 wt % of a monomer capable of copolymerizing with these monomers.

Abstract: A method for controlling a solution process for the polymerisation of olefins is disclosed. The method is based on an algorithm that calculates predicted operating parameters of the process, including calculation of the extent of reaction (?), as a function of the solution density (?), and then calculation of the whole composition of the solution. The algorithm resolves a system of equations comprising the equation of state in the PC-SAFT form, the Lewis-Mayo equation for monomer incorporation into a copolymer, and the stoichiometry equation. Predicted parameters are compared to target parameters to detect possible deviations and implement corresponding compensation in the feed.

Abstract: Process for preparing polyolefins having high molecular weights in the presence of a catalyst comprising an organic transition metal compound in a gas-phase fluidized-bed reactor, where the polyolefins prepared have a melt flow rate at 2.16 kg and 190° C. in accordance with ISO 1133 of less than 4 g/10 min. According to the present invention, a start-up phase during which a polyolefin having an increased melt flow rate of above 4 g/10 min is produced for a transitional period is provided. In this way, trouble-free start-up of the reactor is ensured even in the case of polymer products having a high molecular weight and a melt flow rate below 4 g/10 min and even when using catalysts based on organic transition metal compounds, in particular metallocene catalysts.

Abstract: The present invention relates to a method for performing a polymerization process in a stirred reactor, wherein a critical time window is determined by means of a monitor of at least one polymerization process parameter and an associated process window, and when a critical time window is present, an adaptation of process conditions is made in order to configure the polymerization process to conform to the process window.

Abstract: Disclosed herein is an optimization method in a polymerization system in which heat is generated during the polymerization with an initiator.

Abstract: A method for the control of a polymerization process, which method employs the combination of a densitometer measurement of the polymerization reaction mixture and a quadratic computer model.

Abstract: A method for monitoring a polymer resin-producing polymerization reaction in a fluid bed reactor, including by determining in on-line fashion a maximum diluent (e.g., ICA) concentration and an optimal diluent (e.g., ICA) concentration in the reactor, whereby performing the reaction with diluent (e.g., ICA) concentration less than the maximum diluent concentration ensures an acceptably low risk that the resin in the reactor in the presence of condensable diluent gas will reach a condition of limiting stickiness. Preferably, the optimal diluent concentration maximizes production rate subject to relevant constraints. The method can also include at least one of the steps of controlling the reaction to achieve a desired production rate by controlling diluent (e.g.

Abstract: In some embodiments, a method including the steps of monitoring a polymerization reaction which produces a polymer resin in a fluid bed reactor, where a dry melt reference temperature is characteristic of melting behavior of a dry version of the resin, and in response to data indicative of at least one monitored parameter of the reaction, determining in on-line fashion a reduced melt reference temperature that is at least substantially equal to the difference between the dry melt reference temperature and a temperature by which the dry melt reference temperature is depressed by the presence of condensable diluent gas with the resin in the reactor. Optionally, the method also includes the step of controlling the reaction in response to the reduced melt reference temperature or a stickiness parameter determined from the reduced melt reference temperature.

Abstract: An apparatus for continuous polymerization with a simple constitution to produce a polymer having a high quality, as well as a method for producing the polymer using the apparatus, are provided. The apparatus comprises a vessel; a means for supplying a monomer to the vessel; a means for supplying a polymerization initiator to the vessel; a means for detecting a temperature in the vessel; a means for regulating a temperature of an outer wall surface of the vessel so as to have a preset temperature; and a means for controlling a supply flow rate of the monomer and/or the polymerization initiator to the vessel by the monomer supply means and/or the initiator supply means so that the temperature in the vessel becomes substantially the same temperature as the preset temperature.

Abstract: Methods and system for in-situ measurement of polymer growth within an olefin polymerization reactor are provided. The method includes polymerizing one or more olefins within a reactor at a first temperature sufficient to deposit a polymer coating therein. A second temperature is created within the reactor, and a rate of temperature change is measured from the first temperature to the second temperature. The rate of temperature change is correlated to a thickness of the polymer coating deposited within the reactor.