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: Systems and methods for monitoring a polymerization reactor are provided. The method can include estimating an acoustic condition of a polymer produced in a reactor. The method can also include estimating a stickiness control parameter of the polymer produced in the reactor. The method can further include pairing the acoustic condition with the stickiness control parameter to provide a paired acoustic condition and stickiness control parameter.

Abstract: A method for cleaning a distributor plate in a fluidized bed polymerization reactor system according to one embodiment includes, in a first mode, operating with about a normal, baseline value of superficial gas velocity in a fluidized bed polymerization reactor system having a reactor vessel, a recycle line, and a distributor plate in the reactor vessel near an inlet of the reactor vessel. In a second mode, the superficial gas velocity is increased above the baseline value of the first mode to a level sufficient to raise the temperature of the cycle gas at the inlet above an average temperature of the cycle gas at the inlet in the first mode, and to a level sufficient to dislodge foulant from holes in the distributor plate.

Abstract: Methods for shutting down and restarting polymerization in a gas phase polymerization reactor are provided. The method can include introducing a polymerization neutralizer to the reactor in an amount sufficient to stop polymerization therein. The method can also include stopping recovery of a polymer product from the reactor and stopping introduction of a catalyst feed and a reactor feed to the reactor. The method can also include adjusting a pressure within the reactor from an operating pressure to an idling pressure. The method can also include adjusting a superficial velocity of a cycle fluid through the reactor from an operating superficial velocity to an idling superficial velocity. The method can also include maintaining the reactor in an idled state for a period of time.

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: Systems and methods for monitoring a polymerization reactor are provided. The method can include estimating an acoustic condition of a polymer produced in a reactor. The method can also include estimating a stickiness control parameter of the polymer produced in the reactor. The method can further include pairing the acoustic condition with the stickiness control parameter to provide a paired acoustic condition and stickiness control parameter.

Abstract: A process for the production of an ethylene alpha-olefin copolymer is disclosed, the process including polymerizing ethylene and at least one alpha-olefin by contacting the ethylene and the at least one alpha-olefin with a metallocene catalyst in at least one gas phase reactor at a reactor pressure of from 0.7 to 70 bar and a reactor temperature of from 20° C. to 150° C. to form an ethylene alpha-olefin copolymer. The resulting ethylene alpha-olefin copolymer may have a density D of 0.927 g/cc or less, a melt index (I2) of from 0.1 to 100 dg/min, a MWD of from 1.5 to 5.0. The resulting ethylene alpha-olefin copolymer may also have a peak melting temperature Tmax second melt satisfying the following relation: Tmax second melt>D*398?245.

Abstract: In some embodiments, a method in which at least one continuity additive (“CA”) and a seed bed are pre-loaded into a reactor, and a polymerization reaction is optionally then performed in the reactor. In other embodiments, at least one flow improver, at least one CA, and a seed bed are pre-loaded into a reactor. Pre-loading of a reactor with a CA can significantly improve continuity of a subsequent polymerization reaction in the reactor during its initial stages, including by reducing sheeting and fouling. The CA can be pre-loaded in dry form (e.g., as a powder), or in liquid or slurry form (e.g., as an oil slurry). To aid delivery of a dry CA to the reactor and combination of the dry CA with a seed bed in the reactor, the dry CA can be combined with a flow improver and the combination of CA and flow improver then loaded into the reactor.

Abstract: A method for cleaning a distributor plate in a fluidized bed polymerization reactor system according to one embodiment includes, in a first mode, operating with about a normal, baseline value of superficial gas velocity in a fluidized bed polymerization reactor system having a reactor vessel, a recycle line, and a distributor plate in the reactor vessel near an inlet of the reactor vessel. In a second mode, the superficial gas velocity is increased above the baseline value of the first mode to a level sufficient to raise the temperature of the cycle gas at the inlet above an average temperature of the cycle gas at the inlet in the first mode, and to a level sufficient to dislodge foulant from holes in the distributor plate.

Abstract: Embodiments of the present invention relate to measuring and controlling static in a gas phase reactor polymerization. In particular, embodiments relate to monitoring carryover static in an entrainment zone during gas phase polymerization to determine the onset of reactor discontinuity events such as chunking and sheeting. Embodiments also relate to monitoring carryover static to determine the need for effective additions of continuity additives that minimize reactor static activity and thereby preventing discontinuity events.

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: A process for the production of an ethylene alpha-olefin copolymer is disclosed, the process including polymerizing ethylene and at least one alpha-olefin by contacting the ethylene and the at least one alpha-olefin with a metallocene catalyst in at least one gas phase reactor at a reactor pressure of from 0.7 to 70 bar and a reactor temperature of from 20° C. to 150° C. to form an ethylene alpha-olefin copolymer. The resulting ethylene alpha-olefin copolymer may have a density D of 0.927 g/cc or less, a melt index (I2) of from 0.1 to 100 dg/min, a MWD of from 1.5 to 5.0. The resulting ethylene alpha-olefin copolymer may also have a peak melting temperature Tmax second melt satisfying the following relation: Tmax second melt>D*398?245.

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 is 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: A method for controlling sheeting in a gas phase reactor that includes producing a polyolefin with at least one metallocene catalyst and at least one static control agent in at least one gas phase reactor, measuring entrainment static using a static probe, and adjusting the concentration of the static control agent in response to changes in the measured entrainment static is disclosed.

Abstract: In some embodiments, a method including the steps of: during a polymerization reaction producing a polymer resin in a fluid bed reactor, measuring reaction parameters including at least reactor temperature, at least one property of the resin, and amount of at least one condensable diluent gas in the reactor; determining from at least one measured resin property using a predetermined correlation, a dry melt initiation temperature value for a dry version of the polymer resin; and during the reaction, using a melt initiation temperature depression model to determine in on-line fashion a reduced melt initiation temperature for the resin (e.g., a temperature at which the resin is expected to begin to melt) in the presence of the at least one condensable diluent gas in the 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: 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 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: In some embodiments, a method in which at least one continuity additive (“CA”) and a seed bed are pre-loaded into a reactor, and a polymerization reaction is optionally then performed in the reactor. In other embodiments, at least one flow improver, at least one CA, and a seed bed are pre-loaded into a reactor. Pre-loading of a reactor with a CA can significantly improve continuity of a subsequent polymerization reaction in the reactor during its initial stages, including by reducing sheeting and fouling. The CA can be pre-loaded in dry form (e.g., as a powder), or in liquid or slurry form (e.g., as an oil slurry). To aid delivery of a dry CA to the reactor and combination of the dry CA with a seed bed in the reactor, the dry CA can be combined with a flow improver and the combination of CA and flow improver then loaded into the reactor.

Abstract: Embodiments of the present invention relate to measuring and controlling static in a gas phase reactor polymerization. In particular, embodiments relate to monitoring carryover static in an entrainment zone during gas phase polymerization to determine the onset of reactor discontinuity events such as chunking and sheeting. Embodiments also relate to monitoring carryover static to determine the need for effective additions of continuity additives that minimize reactor static activity and thereby preventing discontinuity events.

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.