Abstract: Ethylene, alpha olefins, and other olefinically unsaturated monomers may be polymerized under fluidized bed polymerization reaction conditions in the presence of a Ziegler-Natta catalyst. A recycle stream featuring an induced condensing agent (ICA) comprising isobutane may increase catalyst productivity while maintaining quality of the polymer product, particularly when the recycle stream is delivered to a reactor containing the fluidized bed under conditions suitable to form a condensed or super-condensed mode in the recycle stream. The recycle stream may comprise unreacted olefinic monomers, and isobutane or a mixture of isobutane and isopentane.

Abstract: Embodiments of the present disclosure are directed towards methods for controlling a polymerization reaction including determining an instantaneous density model for a gas-phase polymerization, and utilizing the instantaneous density model to monitor the polymerization reaction to determine if a threshold instantaneous density is reached.

Abstract: A method for controlling the start up conditions in a gas phase polymerization process is provided. An inventory can be calculated for each monomer, comonomer, and hydrogen sufficient to produce a polyethylene polymer having desired properties, such as, a certain melt index and/or density.

Abstract: Systems and methods for monitoring a particle/fluid mixture are provided. The method can include flowing a mixture comprising charged particles and a fluid past a particle accumulation probe. The method can also include measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe. The measured electrical signals can be manipulated to provide an output. The method can also include determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.

Abstract: Systems and methods for monitoring a particle/fluid mixture are provided. The method can include flowing a mixture comprising charged particles and a fluid past a particle accumulation probe. The method can also include measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe. The measured electrical signals can be manipulated to provide an output. The method can also include determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.

Abstract: Processes for the polymerization of olefins with extracted metal carboxylate salts are provided. The polymerization processes have increased productivity and/or increased resin bulk density.

Abstract: Described herein are methods for monitoring and restoring electrical properties of polymerization reactor wall films. The method may comprise using a reactor wall monitor to monitor and determine an electrical property, such as the bed voltage or breakdown voltage, of the wall film. The method may further comprise adding continuity additive to the reactor and/or adjusting the feed rate of continuity additive being added to the reactor in response to the measured electrical property.

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: Processes for the polymerization of olefins with extracted metal carboxylate salts are provided. The polymerization processes have increased productivity and/or increased resin bulk density.

Abstract: Methods for gas phase olefin polymerization are provided. The method can include combining a spray dried catalyst system with a diluent to produce a catalyst slurry. The catalyst system can include a metallocene compound. Ethylene, a continuity additive, and the catalyst slurry can be introduced to a gas phase fluidized bed reactor. The reactor can be operated at conditions sufficient to produce a polyethylene. The spray dried catalyst system can have a catalyst productivity of at least 12,000 grams polyethylene per gram of the catalyst system.

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: Disclosed is a method for using at least one static probe during polymerization in a fluid bed polymerization reactor system to monitor a coating on a surface of the reactor system and a distal portion of each static probe, wherein the coating is exposed to flowing fluid within the reactor system during the reaction. The surface may be a reactor bed wall (exposed to the reactor's fluid bed) and the coating is exposed to flowing, bubbling fluid within the fluid bed during the reaction. The method may include steps of: during the polymerization reaction, operating the static probe to generate a sequence of data values (“high speed data”) indicative of fluid flow variation (e.g., bubbling or turbulence), and determining from the high speed data at least one electrical property of the coating (e.g., of a portion of the coating on the distal portion of the static probe).

Abstract: Systems and methods for monitoring a particle/fluid mixture are provided. The method can include flowing a mixture comprising charged particles and a fluid past a particle accumulation probe. The method can also include measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe. The measured electrical signals can be manipulated to provide an output. The method can also include determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.

Abstract: Described herein are methods for monitoring and restoring electrical properties of polymerization reactor wall films. The method may comprise using a reactor wall monitor to monitor and determine an electrical property, such as the bed voltage or breakdown voltage, of the wall film The method may further comprise adding continuity additive to the reactor and/or adjusting the feed rate of continuity additive being added to the reactor in response to the measured electrical property.

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.