Abstract: A method for controlling the temperature in a polymerization reactor equipped with a cycle gas line for withdrawing reactor gas from the reactor, leading the reactor gas through a heat-exchanger, which is cooled by a cooling medium, which is conveyed in a cooling system through the heat-exchanger, and feeding the reactor gas back to the reactor by adjusting the temperature of the cooling medium entering the heat exchanger, wherein the temperature of the cooling medium entering the heat exchanger is controlled by adjusting the flow rate of the cooling medium in a part of the cooling system by a flow control system comprising two continuously operating flow control devices of different size, which are connected in parallel, a process for polymerizing olefins and a process for controlling the flow rate of a fluid medium.

Abstract: A method for controlling the temperature in a polymerization reactor equipped with a cycle gas line for withdrawing reactor gas from the reactor, leading the reactor gas through a heat-exchanger, which is cooled by a cooling medium, which is conveyed in a cooling system through the heat-exchanger, and feeding the reactor gas back to the reactor by adjusting the temperature of the cooling medium entering the heat exchanger, wherein the temperature of the cooling medium entering the heat exchanger is controlled by adjusting the flow rate of the cooling medium in a part of the cooling system by a flow control system comprising two continuously operating flow control devices of different size, which are connected in parallel, a process for polymerizing olefins and a process for controlling the flow rate of a fluid medium.

Abstract: Process and apparatus for discharging polyolefin particles from a gas-phase polymerization reactor of a pressure from 1.0 MPa to 10 MPa to a discharge vessel of a pressure from 0.1 MPa to 1.0 MPa wherein the discharging is carried out discontinuously through at least two discharge lines in which the polyolefin particles are transported horizontally or upwards.

Abstract: Process for discharging polyolefin particles from a gas-phase polymerization reactor of a pressure from 1.0 MPa to 10 MPa to a discharge vessel of a pressure from 0.1 MPa to 1.0 MPa wherein the discharging is carried out discontinuously through at least two discharge lines in which the polyolefin particles are transported horizontally or upwards, process for polymerizing olefins at temperatures of from 30° C. to 160° C. and pressures of from 1.

Abstract: A continuous gas-phase process for the polymerization of alpha-olefins, in particular ethylene, comprising passing an alpha-olefin monomer stream through an oil filter in order to reduce the amount of oil to less than 8 ppm, and polymerizing the thus purified monomer feed in gas-phase reactor; the reduction of the amount of oil improves the operability of the plant over time.

Abstract: A continuous gas-phase process for the polymerization of alpha-olefins, in particular ethylene, comprising passing an alpha-olefin monomer stream through an oil filter in order to reduce the amount of oil to less than 8 ppm, and polymerizing the thus purified monomer feed in gas-phase reactor; the reduction of the amount of oil improves the operability of the plant over time.

Abstract: For producing homopolymers or copolymers of propylene in the gas phase, gaseous or liquid monomers are introduced into a polymerization zone; the pressure and temperature in the polymerization zone are kept within a range that corresponds to the gaseous state of the monomers; gaseous monomers not consumed by polymerization are discharged from the polymerization zone and liquefied and re-introduced in liquid form into the polymerization zone. The temperature regulation in the polymerization zone is done by means of continuous measurement of the temperature and a change, tripped upon a change in temperature, in the quantity of liquid monomers introduced per unit of time into the reaction zone. To that end, the temperature is measured at a plurality of points vertically offset from one another, and from the respective measured values a respective mean value is formed.

Abstract: For producing homopolymers or copolymers of propylene in the gas phase, gaseous or liquid monomers are introduced into a polymerization zone; the pressure and temperature in the polymerization zone are kept within a range that corresponds to the gaseous state of the monomers; gaseous monomers not consumed by polymerization are discharged from the polymerization zone and liquefied and re-introduced in liquid form into the polymerization zone. The temperature regulation in the polymerization zone is done by means of continuous measurement of the temperature and a change, tripped upon a change in temperature, in the quantity of liquid monomers introduced per unit of time into the reaction zone. To that end, the temperature is measured at a plurality of points vertically offset from one another, and from the respective measured values a respective mean value is formed.