Methods for producing a polymer include contacting at least one monomer under polymerization conditions with a fluidized bed of a polymerization catalyst on a particulate support; measuring a plurality of pressures of the fluidized bed at a plurality of locations corresponding to increasing heights from a bottom of the fluidized bed; calculating a plurality of pressure drops between the plurality of locations based on the measured pressures; performing a regression analysis on the calculated plurality of pressure drops; correlating the plurality of pressure drops to corresponding heights from the bottom of the fluidized bed based on the regression analysis; determining a height of the fluidized bed based on the correlating; and controlling polymerization conditions based on the determined height of the fluidized bed. The method can also be used to detect malfunctioning pressure transducers based on deviation between measured and expected values.

Methods for producing a polymer include contacting at least one monomer under polymerization conditions with a fluidized bed of a polymerization catalyst on a particulate support; measuring a plurality of pressures of the fluidized bed at a plurality of locations corresponding to increasing heights from a bottom of the fluidized bed; calculating a plurality of pressure drops between the plurality of locations based on the measured pressures; performing a regression analysis on the calculated plurality of pressure drops; correlating the plurality of pressure drops to corresponding heights from the bottom of the fluidized bed based on the regression analysis; determining a height of the fluidized bed based on the correlating; and controlling polymerization conditions based on the determined height of the fluidized bed. The method can also be used to detect malfunctioning pressure transducers based on deviation between measured and expected values.

This invention relates to a self cleaning reactor and to a process for the oligomerization of ethylene that employs a self-cleaning reactor. The reactor includes a mass of inert, particulate cleaning bodies that are entrained by the liquid in the reactor and scour the internal surfaces of the reactor during normal operation. This scouring action reduces the level of fouling on the reactor surfaces. Foulant material (polyethylene) is removed from the process on a continuous basis but the cleaning bodies remain within the reactor.

This invention relates to a self cleaning reactor and to a process for the oligomerization of ethylene that employs a self-cleaning reactor. The reactor includes a mass of inert, particulate cleaning bodies that are entrained by the liquid in the reactor and scour the internal surfaces of the reactor during normal operation. This scouring action reduces the level of fouling on the reactor surfaces. Foulant material (polyethylene) is removed from the process on a continuous basis but the cleaning bodies remain within the reactor.

Provided is a method of predicting fouling during a process of preparing polyolefin. According to the present invention, occurrence of fouling may be predicted by calculating R value according to the following Equation 1 in real-time with high reliability during a copolymerization process of preparing polyolefin:
R (ratio of unreacted alpha-olefin comonomer to produced polyolefin polymer) =amount of unreacted alpha-olefin comonomer (unit: kg/hr) / amount of produced polyolefin polymer (unit: kg/hr)   [Equation 1] Therefore, productivity of the polyolefin preparation process may be further increased.

Provided is a method of predicting fouling during a process of preparing polyolefin. According to the present invention, occurrence of fouling may be predicted by calculating R value according to the following Equation 1 in real-time with high reliability during a copolymerization process of preparing polyolefin:
R (ratio of unreacted alpha-olefin comonomer to produced polyolefin polymer) =amount of unreacted alpha-olefin comonomer (unit: kg/hr) / amount of produced polyolefin polymer (unit: kg/hr)   [Equation 1] Therefore, productivity of the polyolefin preparation process may be further increased.

The present invention provides a polyarylene sulfide (PAS) production device which suppresses the accumulation of deposits on a baffle (baffle board) or the like disposed inside a reaction vessel via a baffle support for the purpose of enhanced stirring efficiency or the like, thereby contributing to enhanced production efficiency, reduced cost of removing accumulation, and enhanced quality of the PAS product.

The PAS production device of the present invention is a PAS production device provided with a reaction vessel equipped with one or a plurality of baffles; each baffle being supported by one or a plurality of baffle supports provided in a protruding manner on an inside wall of the reaction vessel; and at least one of the baffle supports having one or a plurality of openings preferably passing through the baffle support in the vertical direction.

A method for producing a polyolefin is provided. The method includes a step of feeding a polyolefin powder having a catalytic activity into a gas phase polymerization vessel in which there is a polyolefin powder and through which a gas comprising an olefin is being circulated, thereby commencing polymerization of an olefin. The following formula (1) is satisfied:

0.5<β/(αB)<24.0  (1)

In formula (1), α represents the median diameter (μm) of the catalytically active polyolefin powder to be fed into the vapor phase polymerization vessel, β represents the median diameter (μm) of the polyolefin powder that is contained in the vapor phase polymerization vessel before the feeding of the catalytically active polyolefin powder into the vapor phase polymerization vessel, and B represents the linear gas velocity (m/sec) of the gas containing an olefin within the vapor phase polymerization vessel.

A method for producing a polyolefin is provided. The method includes a step of feeding a polyolefin powder having a catalytic activity into a gas phase polymerization vessel in which there is a polyolefin powder and through which a gas comprising an olefin is being circulated, thereby commencing polymerization of an olefin. The following formula (1) is satisfied:

0.5<β/(αB)<24.0  (1)

In formula (1), α represents the median diameter (μm) of the catalytically active polyolefin powder to be fed into the vapor phase polymerization vessel, β represents the median diameter (μm) of the polyolefin powder that is contained in the vapor phase polymerization vessel before the feeding of the catalytically active polyolefin powder into the vapor phase polymerization vessel, and B represents the linear gas velocity (m/sec) of the gas containing an olefin within the vapor phase polymerization vessel.

The present invention relates to an additive composition for controlling and inhibiting polymerization of monomers, wherein the composition comprises a combination of (a) a phenol compound comprising catechol compound with (b1) an aliphatic tertiary amine, (b2) oxide treated derivative of the aliphatic tertiary amine, or (b2) a mixture thereof, wherein the aliphatic tertiary amine contains one or more hydroxyl groups in the alkyl chain of the aliphatic tertiary amine. In one embodiment, the present invention also relates to a method for controlling and inhibiting polymerization of monomers by employing the additive composition of the present invention. In another embodiment, the present invention also relates to a method of using the additive composition of the present invention for controlling and inhibiting polymerization of monomers. In another embodiment, the present invention also relates to methods for controlling and inhibiting polymerization of monomers in a primary fractionator (or an ethylene plant), and for operating a primary fractionator, and for reducing fouling and polymer deposits in a primary fractionator, and to extend a run-length of a primary fractionator or of an ethylene plant.