Granular polysilicon is produced in a fluidized-bed reactor by fluidizing silicon particles by means of a gas flow in a fluidized bed heated to a temperature of 850-1100 C., adding a silicon-containing reaction gas by means of a nozzle and depositing of silicon on the silicon particles, wherein, in at least 56% of an axially symmetric region around a nozzle opening of the nozzle, the reaction gas concentration is greater than 75% of the maximum concentration of the reaction gas (10 to 50 mol %), the fluidized-bed temperature is greater than 95% of the fluidized-bed temperature outside the axially symmetric region (850-1100 C.) and the solids concentration is greater than 85% of the solids concentration at the edge of the fluidized bed (55 to 90% by volume).

A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of the reactor feed stream, wherein the reactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the reactor feed stream into a concentration of the solid component in the reactor feed stream. A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of a precontactor feed stream, wherein the precontactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the precontactor feed stream into a concentration of the solid component in a precontactor effluent stream, wherein the precontactor effluent stream comprises the reactor feed stream.

A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of the reactor feed stream, wherein the reactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the reactor feed stream into a concentration of the solid component in the reactor feed stream. A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of a precontactor feed stream, wherein the precontactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the precontactor feed stream into a concentration of the solid component in a precontactor effluent stream, wherein the precontactor effluent stream comprises the reactor feed stream.

A process and device for the flow of catalyst in a reactor is presented. The device includes a series of grids within a reactor vessel, where each grid includes small openings for the passage of gas and some catalyst particles, and larger openings for the more continuous passage of catalyst. The grids span horizontally across the vessel, and are spaced vertically apart to provide for the flow of catalyst down through the reactor.

The invention relates to a method for regulating the gas velocity of the empty bed in a fluidized bed, wherein solid catalysts are used as fluidized particles or as a part of fluidized particles, characterized in that the gas velocity of the empty bed of the reaction zone of the fluidized bed is measured, compared with the bed average catalyst density of the solid catalysts in the reaction zone of the fluidized bed, the gas velocity of the empty bed being adjusted as required such that the gas velocity of the empty bed and the bed average catalyst density satisfy the formula (I) below: =0.356.sup.34.319.sup.235.57+M; wherein M=250; where is provided in m/s and is provided in kg/m.sup.3. The method can be used for the industrial production of lower olefin.

The invention relates to a method for self-regulation of a system comprising the steps of: (I) utilizing a magnetic field to transport magnetizable and/or magnetic particles out of a control volume or to localize said particles in the control volume, (II) changing magnetic properties of the magnetizable and/or magnetic particles, which are ferromagnetic or paramagnetic, in the control volume by changing a temperature Tp of the magnetizable and/or magnetic particles or by changing the composition of the magnetizable and/or magnetic particles.

Disclosed herein are methods and systems for purging a polymer product of volatiles. The methods and systems are particularly useful in the purging of a polyethylene polymer product produced in a fluidized bed reactor.

A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of the reactor feed stream, wherein the reactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the reactor feed stream into a concentration of the solid component in the reactor feed stream. A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of a precontactor feed stream, wherein the precontactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the precontactor feed stream into a concentration of the solid component in a precontactor effluent stream, wherein the precontactor effluent stream comprises the reactor feed stream.

The present disclosure relates to a fluidized bed reactor system capable of regenerating fluidized particles and operating method thereof, more particularly to a fluidized bed reactor system capable of regenerating fluidized particles including: a fluidized reactor into which a fluidizing gas is injected; a regeneration fluidized bed reactor with a gas inlet and a gas outlet; a solid moving path that is connected between the fluidized bed reactor and the regeneration fluidized bed reactor to transfer solid particles; a first control valve that is installed on one side of the solid moving path; and a second control valve that is installed on the gas outlet of the regeneration fluidized bed reactor.

The present specification relates to a method comprising: (A) mixing a ferrite-based catalyst molded article with diluent material particles; and (B) adding the mixture to a catalyst reactor, and a method for preparing butadiene using the same.