Abstract: A process for the preparation of a polyolefin is disclosed. The process includes introducing one or more olefin reactants, diluents and polymerization catalyst into a first loop reactor, and while circulating the olefin reactants, diluents and polymerization catalyst in the first loop reactor. The method includes polymerizing the one or more olefin reactants to produce a polyolefin slurry comprising liquid diluent and solid olefin polymer particles.

Abstract: A process for the preparation of a polyolefin in a slurry loop reactor provided with settling legs may include introducing olefin reactants, diluents, and polymerization catalyst into the reactor while circulating. The process may include polymerizing the olefin reactants to produce a slurry, continuously withdrawing the slurry, via the settling legs, and transferring withdrawn solid olefin polymer particles to a recovery section. Each settling leg may have an inlet connected to the reactor and an outlet connected to the recovery section. At least one settling leg is continuously open, allowing continuous withdrawal of slurry. Each outlet of the settling legs may be connected to the recovery section by a conduit provided with a pressure control device. The pressure in the reactor may be controlled by operating the pressure control device.

Abstract: A process for the preparation of a polyolefin in at least two slurry loop reactors including a first loop reactor connected in series with a second loop reactor includes introducing olefin reactants, diluents and polymerization catalyst into the first loop reactor while circulating. The process includes polymerizing the olefin reactants to produce a polyolefin slurry, withdrawing the polyolefin slurry from the first loop reactor, and introducing withdrawn articles into the second loop reactor by means of settling legs. Each settling leg has an inlet connected to the first loop reactor and an outlet connected to the second loop reactor by means of a transfer line. At least one settling leg is continuously open allowing continuous transfer of solid olefin polymer particles from the first to the second loop reactor. The process includes controlling the continuous transfer of solid olefin polymer particles by the at least one continuously open settling leg.

Abstract: A process for the preparation of a polyolefin in a slurry loop reactor provided with settling legs may include introducing olefin reactants, diluents, and polymerization catalyst into the reactor while circulating. The process may include polymerizing the olefin reactants to produce a slurry, continuously withdrawing the slurry, via the settling legs, and transferring withdrawn solid olefin polymer particles to a recovery section. Each settling leg may have an inlet connected to the reactor and an outlet connected to the recovery section. At least one settling leg is continuously open, allowing continuous withdrawal of slurry. Each outlet of the settling legs may be connected to the recovery section by a conduit provided with a pressure control device. The pressure in the reactor may be controlled by operating the pressure control device.