Univation Technologies, LLC

Daniel N Thomas, Jr

Timothy R Lynn

Bruce Jon Savatsky

John Francis Szul

Eric John Markel

Fathi David Hussein

Ping P Cai

Jose Fernando Cevallos-Candau

Ian D Burdett

W Scott Hamilton

A method including a) polymerizing at least one monomer in a gas phase reactor in the presence of a supported multimodal catalyst system to form a multimodal polyethylene product having a reactor split equal to respective weight fractions of resin components in the polyethylene product; b) applying a predetermined formula for a product parameter of the multimodal polyethylene product; c) obtaining incorporation data and production rate data from the reaction based upon the predetermined formula; d) determining an actual hydrogen leading indicator; e) comparing the actual hydrogen leading indicator to a target value for a hydrogen leading indicator to determine a deviation of the actual hydrogen leading indicator from the target value; and f) adjusting an amount of a catalyst precursor being fed to the gas phase reactor to control reactor split and a product parameter.

Controlling reactor split and a product parameter

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.

Methods of monitoring and controlling the melt index of a polyolefin product during production

A process for the polymerization of olefin's, including: introducing an olefin and a polymerization catalyst into a polymerization reactor to form a polyolefin, the polymerization reactor including: a fluidized bed region having a top and a bottom; and a motive bed region; wherein a first end of the motive bed region is fluidly connected to the top of the fluidized bed region; and wherein a second end of the motive bed region is fluidly connected to the bottom of the fluidized bed region; and wherein a diameter of the fluidized bed region is greater than a diameter of the motive bed region; circulating at least a portion of the olefin, the catalyst, and the polyolefin through the fluidized bed region and the motive bed region; maintaining a dense-phase fluidized bed within the fluidized bed region; recovering polyolefin from the fluidized bed region, is provided. A reactor system directed to the process is also provided.

Reactor systems and processes for using the same

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., ICA) concentration, and controlling the reaction to prevent reactor temperature from reaching a reduced melt reference temperature at least substantially equal to a dry melt reference temperature minus a temperature depression value by which the dry melt reference temperature is depressed by presence of at least one condensable diluent gas with the resin in the reactor.

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South Charleston, WV, United States of America

Daniel N Thomas, Jr