Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

Abstract: Gas-phase fluidized-bed reactor for polymerizing ethylenically unsaturated monomers, comprising a reactor chamber (1) in the form of a vertical tube, if desired a calming zone (2) following the upper section of the reactor chamber, a circulation gas line (3), a circulation gas compressor (4) and a cooling device (5), where, in the region of transition of the reaction gas from the circulation gas line into the reactor chamber and in the lower section of the reactor chamber itself, there is either no gas distributor plate at all or only a gas distributor plate the total surface area of whose gas orifices is more than 20% of the total surface area of said gas distributor plate.

Abstract: Method of metering at least one solid, particulate catalyst into a reactor containing a fluidized bed (11) of particles in an at least partly gaseous medium, in which the catalyst is metered discontinuously at prescribed time intervals into the fluidized bed (11) at at least one metering point (10). According to the present invention, a fluid stream is firstly introduced into the reactor (5) so that a region having a reduced particle density is formed in the fluidized bed (11) around the metering point (10) and the catalyst is subsequently metered into this region. As a result of the prior introduction of a fluid stream (“preblowing”) before the actual introduction of the catalyst, the catalyst can penetrate significantly deeper into the fluidized bed from the metering point due to the reduced particle density and is dispersed better.

Abstract: Method of metering at least one solid, particulate catalyst into a reactor containing a fluidized bed (11) of particles in an at least partly gaseous medium, in which the catalyst is metered discontinuously at prescribed time intervals into the fluidized bed (11) at at least one metering point (10). According to the present invention, a fluid stream is firstly introduced into the reactor (5) so that a region having a reduced particle density is formed in the fluidized bed (11) around the metering point (10) and the catalyst is subsequently metered into this region. As a result of the prior introduction of a fluid stream (“preblowing”) before the actual introduction of the catalyst, the catalyst can penetrate significantly deeper into the fluidized bed from the metering point due to the reduced particle density and is dispersed better.

Abstract: A continuous vapor-phase fluidized-bed process for the preparation of ethylene homopolymers and copolymers having a density of from 0.87 to 0.97 g/cm3 in which ethylene or mixtures of ethylene and C3-C8 a-monoolefins are (co)polymerized in the presence of a supported chromium catalyst in the polymerization zone of a vapor-phase fluidized-bed reactor under pressures ranging from 1 to 100 bar and at temperatures ranging from 30° to 125° C. in the vapor phase in an agitated bed of bulk material comprising particulate polymer, the resultant heat of polymerization is removed by cooling the recirculated reactor gas and the resulting (co)polymer is removed from the vapor-phase fluidized-bed reactor, wherein, for the preparation of a (co)polymer of a specific density d, the (co)polymerization is carried out at a temperature which is in a range restricted by an upper envelope defined by equation I T H = 171 + 6 ? ? ? d ? 0.

Abstract: A continuous vapor-phase fluidized-bed process for the preparation of ethylene homopolymers and copolymers having a density of from 0.87 to 0.97 g/cm3 in which ethylene or mixtures of ethylene and C3-C8 a-monoolefins are (co)polymerized in the presence of a supported chromium catalyst in the polymerization zone of a vapor-phase fluidized-bed reactor under pressures ranging from 1 to 100 bar and at temperatures ranging from 30° to 125° C. in the vapor phase in an agitated bed of bulk material comprising particulate polymer, the resultant heat of polymerization is removed by cooling the recirculated reactor gas and the resulting (co)polymer is removed from the vapor-phase fluidized-bed reactor, wherein, for the preparation of a (co)polymer of a specific density d, the (co)polymerization is carried out at a temperature which is in a range restricted by an upper envelope defined by equation I 1 T H = 171 + 6 ⁢   ⁢ d ′ 0.

Abstract: Method for the discontinuous thermal treatment of catalyst material comprising the steps (a) introducing the catalyst material into a reactor, (b) heating the catalyst material, (c) thermally treating the catalyst material in the reactor at the reactor temperature, (d) discharging the catalyst material from the reactor and (e) cooling the catalyst material, wherein the reactor temperature is kept constant during the steps (a) to (e), step (b) is carried out during and/or after step (a), step (e) is carried out during and/or after step (d), and step (c) is carried out after step (b) and before step (e). The method is used primarily for the calcination or activation of catalysts or catalyst supports which are used in polyolefin production.

Abstract: A continuous vapor-phase fluidized-bed process for the preparation of ethylene homopolymers and copolymers having a density of from 0.87 to 0.97 g/cm3 in which ethylene or mixtures of ethylene and C3-C8 a-monoolefins are (co)polymerized in the presence of a supported chromium catalyst in the polymerization zone of a vapor-phase fluidized-bed reactor under pressures ranging from 1 to 100 bar and at temperatures ranging from 30° to 125° C.

Abstract: A method for the treatment of catalyst or catalyst support material in an apparatus in which the treatment is carried out continuously in such a way that the physical and/or chemical conditions change during entry of the catalyst or catalyst support material into the apparatus and/or during exit thereof from the apparatus and/or the catalyst or catalyst support material is transported in the apparatus through zones (5, 6, 7) having different physical and/or chemical conditions.

Abstract: The present invention relates to a method for the isolation of olefins from a gas mixture comprising one or more olefins, inert gas and catalyst poison, where the gas mixture is fed to a separation unit (18) and separated into olefin and inert gas. The method according to the invention has the special feature that an apparatus (17) is installed upstream or downstream of the separation unit (18) and that i) in the case of an upstream apparatus (17), the catalyst poison is at least partially removed from the gas mixture, and ii) in the case of a downstream apparatus (17), the catalyst poison is at least partially removed from the separated-off olefin. The olefins here are preferably isolated from a gas mixture formed as offgas in catalytic gas-phase polymerization for the preparation of polyolefins. The recovery of the olefins from the offgas is of economic importance.

Abstract: In a continuous gas-phase polymerization process for preparing ethylene and propene homopolymers and copolymers, in which ethylene, propene or a mixture of ethylene or propene and C3-C8-&agr;-monoolefins is polymerized in the polymerization zone of a gas-phase polymerization reactor at from 30 to 125° C. and a pressure of from 1 to 100 bar in the gas phase in a bed of finely divided polymer in the presence of a catalyst, where the reactor gas is circulated to remove the heat of polymerization, polymer deposits in the circulating gas line are prevented by metering a catalyst poison having a boiling point above the maximum temperature within the circulating gas line into this circulating gas line in at most such an amount that it does not significantly impair the productivity of the catalyst in the reactor.

Abstract: A process for preparing polyaspartic acid by polycondensation of fine-particle aspartic acid at temperatures above 150.degree. C. in the presence of acidic catalysts, wherein first contact between the acidic catalysts and the fine-particle aspartic acid takes place in the reaction zone where the polycondensation takes place.

Abstract: Particle fluidization method in which particles are swirled up by a flow of a fluidizing gas to form a fluidized bed and pressure measurements are performed in or along the fluidized bed, and in which a parameter for the distribution of the measured values from these pressure measurements is determined and is used as a basis for regulating the flow rate of the stream of fluidizing gas.