Disclosed herein are systems and methods for monitoring and controlling a nitroxide-based polymerization inhibitor in vinyl-based monomers. A dosage of the nitroxide-based polymerization inhibitor is provided in the vinyl-based monomers. A residual concentration of the nitroxide-based polymerization inhibitor is measured substantially in real time, and an optimized dosage of the nitroxide-based polymerization inhibitor is provided in response to the measured residual concentration.

An easily polymerizable substance handling device is provided that can prevent generation of irregularities and steps between a pipeline and a cover member due to the cover member being installed at an opening part of the pipeline. A cover part 3 is formed to have a curved surface 3a on a side closer to inside of a pipeline 1. The shape of the surface 3a on the pipeline 1 side is preferably a concave shape when viewed from inside of the pipeline 1. The shape of the surface 3a of the cover part 3 on the pipeline 1 side is more preferably the shape of a curved surface having a curvature radius equal or approximate to that of the internal circumference of the pipeline 1. With this configuration, a polymer material is unlikely to be generated at the cover part 3 and around a gap 1b at an opening part 1a, and the frequency of cleaning can be reduced as compared to conventional cases.

The present invention refers to the use of hydrofoil impellers for the preparation of polymer polyols and to a method for preparing a polymer polyol, which comprises reacting a base polyol, at least one ethylenically unsaturated monomer and a macromer or a preformed stabilizer in the presence of a free-radical initiator and optionally a chain transfer agent in a reactor, wherein said reactor is stirred by means of a stirring system comprising a shaft rotatable about its longitudinal axis, and a plurality of radially extending hydrofoil impellers mounted on the shaft and respectively axially spaced apart and wherein the reactor does not contain baffles.

A method is described that includes contacting an olefin with a catalyst in a polymerization reactor, polymerizing at least a portion of the olefin to form an alpha olefin reaction product, detecting a condition within the polymerization reactor, determining an average temperature of at least one olefin product particle based on the condition, determining an operating particle temperature threshold using a foul curve, comparing the average temperature of the polymer particle to the operating particle temperature threshold, changing one or more operating parameters in response to the comparing, and maintaining the average temperature of the olefin polymer particle at or below the operating particle temperature threshold in response to changing the one or more operating parameters. The alpha olefin reaction product includes a plurality of olefin polymer particles, and the polymerization reactor includes a reaction mixture that includes the olefin, the catalyst, a diluent, and the alpha olefin reaction product.

Some embodiments of the present invention provide components for a serpentine fluid reactor which is optimized for one or more objective functions of interest such as pressure drop, erosion rate, fouling, coke deposition and operating costs. The components are designed by computer modeling the components individually and collectively in which the cross section of flow path is substantially circular under industrial conditions to validate the model design and its operation. Then iteratively the component designs are deformed and the operation of the deformed part(s) is modeled and compared to values obtained with other deformed models until the value of the objective function is optimized (e.g. at an extreme) or the change in the objective function is approaching zero.

The disclosure provides a flushing process for removing polymer fouling from a reactor including a gas distributor proximal to the bottom thereof and an internal condenser proximal to the top thereof, the method including, for a first flushing time period, injecting a flushing solvent into the reactor and withdrawing the flushing solvent from a reactor outlet proximal to the internal condenser to induce an upward movement of flushing solvent, the withdrawn flushing solvent containing a first polymer content. After the first flushing time period is complete, for a second flushing time period, the process includes injecting a flushing solvent into the reactor and withdrawing the flushing solvent from a reactor outlet proximal to the gas distributor to induce a downward movement of flushing solvent, the withdrawn flushing solvent containing a second polymer content.

Methods for detecting incipient sheeting in a polyolefin gas phase reactor. The method can include flowing one or more monomer gases through a first tubular protruding through a reactor wall, flowing one or more monomer gases through a second tubular protruding through the reactor wall, wherein the first tubular is located within the second tubular, and measuring a pressure differential of the monomer gases flowing through the first and second tubulars. Based on the measured pressure differential, incipient sheeting within the reactor can be detected and one or more redial measures can be employed to control or reverse the sheeting.