Abstract: A reactor for contacting a fluid with a granular solid, the reactor including: a reactor housing including a reaction zone in which the fluid and the granular solid are contacted together; a granular solids inlet adapted to deliver a bed of granular solids into the reaction zone wherein the height and/or width dimension of the bed of the granular solids is substantially less than the length of the bed; a plurality of fluid inlets for delivering the fluid into the reaction zone, whereby the delivery of the fluid into the reaction zone at least partially fluidises the bed of granular solids; a granular solids outlet for receiving the bed of granular solids after having passed through the reaction zone; and, a fluid outlet for receiving the fluid, and any entrained particles, after the fluid has passed through the reaction zone.

Abstract: Disclosed are a fluidized bed water gas shift membrane reactor and a method for separating carbon dioxide using the same. More specifically, disclosed are a fluidized bed water gas shift membrane reactor provided on the back of a gasification reactor to produce a synthetic gas consisting of hydrogen and carbon monoxide by reaction of a solid hydrocarbon with water or oxygen, wherein the carbon monoxide present in an amount of 40 to 70 vol % in the synthesis gas reacts with steam in the presence of a catalyst to produce a mix gas of hydrogen and carbon dioxide, and the hydrogen is selectively isolated from the mix gas through a Pb—Cu shift membrane to increase the concentration of carbon dioxide present in the mix gas and separate the carbon dioxide, and a method for separating carbon dioxide using the same.

Abstract: A method for the manufacture of crystallized polyesters with or without subsequent solid state polycondensation for the manufacture of bottles, foils, films and technical high-performance fibres, or with or without subsequent dealdehydization for the manufacture of bottles, foils, films and technical high-performance fibres.

Abstract: There are disclosed polymerization processes and associated apparatuses. The polymerization processes involve both making a polymeric material in a fluidized bed reactor having a feed distributor and catching a spitwad with a spitwad catcher, and the apparatuses are those corresponding to such processes.

Abstract: A method for preparing polyolefin from alpha-olefin with high productivity using an internal circulating fluidized bed polymerization reactor is disclosed. The method for gas-phase polymerization of alpha-olefin comprising the steps of: supplying circulation gas including one or more alpha-olefins and inert gas into a polymerization reactor; polymerizing the alpha-olefin to polyolefin in two separated polymerization areas in the polymerization reactor; and discharging produced polyolefin from the polymerization reactor.

Abstract: A system for removing sulfur from a gaseous stream includes (a) a reaction bed for receiving the gaseous stream and for reacting sulfur dioxide and at least some of the hydrogen sulfide of the gaseous stream into elemental sulfur to provide an elemental sulfur stream and a first product stream; and (b) a circulating fluidized bed comprising (i) a first region for receiving the first product stream and using a sulfur adsorption material to adsorb and remove any remaining hydrogen sulfide from the first product stream to generate saturated sulfur adsorption material and a second product stream substantially free of sulfur; and (ii) a second region for receiving a regeneration stream and for using the regeneration stream to regenerate the saturated sulfur adsorption material and to generate the sulfur dioxide.

Abstract: Provided are an apparatus for synthesizing carbon nanotubes, the apparatus including a reaction tube that provides a space for carbon nanotubes and is formed vertically long, a heating unit that is formed at the outer side of the reaction tube, and heats the reaction tube, a gas-supply unit that sprays reaction gas for synthesizing the carbon nanotubes by reacting with catalysts positioned inside the reaction tube, an exhaustion unit that is connected to the upper portion of the reaction tube, and discharges non-reacted reaction gas for synthesizing the carbon nanotubes, and a blocking unit that is formed inside the reaction tube, discharges only the non-reacted reaction gas for synthesizing the carbon nanotubes to the exhaustion unit, and blocks the discharge of the carbon nanotubes and catalysts, in which the cross-section of the blocking unit is divided in a plurality of polygon structures, and downward-slanted blocking wings are formed at each divided cell.

Abstract: A method for preparing polyolefin from alpha-olefin with high productivity using an internal circulating fluidized bed polymerization reactor is disclosed. The method for gas-phase polymerization of alpha-olefin comprising the steps of: supplying circulation gas including one or more alpha-olefins and inert gas into a polymerization reactor; polymerizing the alpha-olefin to polyolefin in two separated polymerization areas in the polymerization reactor; and discharging produced polyolefin from the polymerization reactor.

Abstract: A plant for producing metal oxide from metal compounds includes a fluidized-bed reactor in which the metal compounds are heated by a combustion of a fuel to produce metal oxide. The fluidized-bed-reactor reactor includes at least one gas supply tube at least partly surrounded by an annular chamber in which a stationary annular fluidized bed is disposed, and a mixing chamber disposed above an orifice region of the gas supply tube. A gas flowing through the gas supply tube entrains solids from the stationary annular fluidized bed when passing through the orifice region.

Abstract: In an apparatus and method for optimizing the exhaust gas burnout in combustion plants having a solid bed combustion zone and an exhaust gas burnout zone wherein oxygen-containing gas is injected into the exhaust gas flow in the burnout zone by way of a plurality of secondary gas injection nozzles, wherein each injection nozzle is provided with a control valve, means are provided for determining the presence of incompletely burned exhaust gas components in the exhaust gas burn out zone and a control unit converts the signals into control signals by which the valves or group of valves are individually controlled so as to inject oxygen containing gas into the exhaust gas flow in order to concentrate the injection of the oxygen containing secondary gas into the areas in which incompletely burned exhaust gas components are present.

Abstract: A flexible pressure containment coverplate has been invented for radial flow reactors. The coverplate is for a fixed bed reactor wherein the reactor undergoes significant thermal cycles. The coverplate provides flexibility for axial and radial thermal growth, while providing a sealing capability to prevent leakage of the fluid. The coverplate has a half toroidal structure, with a semi-circular cross-section.

Abstract: The disclosure provides methods and systems for sequestering and/or reducing sulfur oxides, nitrogen oxides and/or carbon dioxide present in industrial effluent fluid streams. A solid particulate material comprising a slag component, a binder component (distinct from the slag component), and optionally water is formed and then contacted with the effluent fluid stream to reduce at least one of the sulfur oxides, nitrogen oxides, and/or carbon dioxide. The contacting of the effluent stream may occur in a packed bed reactor with the solid dry particulate material. Methods of reducing pollutants from exhaust generated by combustion sources, lime and/or cement kilns, iron and/or steel furnaces, and the like are provided.

Abstract: A fluidized-bed reactor for carrying out a gas-phase reaction, in which a gaseous reaction mixture flows from the bottom upward through a heterogeneous particulate catalyst forming a fluidized bed and internals are arranged in the fluidized bed, wherein the internals divide the fluidized bed into a plurality of cells arranged horizontally in the fluidized-bed reactor and a plurality of cells arranged vertically in the fluidized-bed reactor, with the cells having cell walls which are permeable to gas and have openings which ensure an exchange number of the heterogeneous particulate catalyst in the vertical direction in the range from 1 to 100 liters/hour per liter of reactor volume, is proposed.

Abstract: The present invention relates to a method for degassing polymer powder comprising flushing the polymer powder in a first chamber with a first flow of flushing gas, transferring the polymer powder into a second chamber and flushing the polymer powder with a second flow of flushing gas in said second chamber. The present invention also relates to a system suitable for carrying out this method.

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: In one embodiment of the present invention a fluid bed reactor is provided, comprising: a housing, at least one tray disposed within the housing, at least one motor operatively connected to the at least one tray, wherein the motor rotates the at least one tray; and at least one wiper associated with at the at least one tray which directs product on a top surface of a respective tray down through at least one radial slot in each respective tray as each respective tray is rotated by the motor. At least one of the trays is at least partially perforated material which a gas to flow up out of the top surface of the tray, at least partially fluidizing product on the top surface of the tray.

Abstract: The invention relates to a fluidized-bed reactor having a higher power density and to an exchangeable insert for said fluidized-bed reactor, which insert makes the higher power density possible. The supply and pre-heating of the fluidizing agent, especially air, to the fluidized bed is combined with the cooling of the reactor vessel wall owing to the preferably exchangeable insert in the fluidized-bed reactor. The “cold” fluidizing agent is guided in at least one flow channel in the metal jacket surrounding the fluidized bed and is preheated and said channel and is then injected into the fluidized bed in an appropriate location. The reactor vessel wall is cooled by pre-heating the fluidizing agent. The desired and required values for cooling the reactor vessel and the desired pre-heating of the fluidizing agent can be adjusted by suitably selecting the parameters ‘length’ and ‘volume’ of the flow channels in the insert and the flow rate of the fluidizing agent in the flow channels.

Abstract: An olefin polymerization reaction unit includes a multistage gas phase polymerization reactor which is divided into two or more polymerization stages, in which polyolefin particles move from an initial stage to a final stage, and in which an olefin monomer-containing gas is fed from the final stage toward the initial stage. The reaction unit also includes first circulating means for feeding to the final stage a gas that is discharged from the initial stage and then cooled with a first heat exchanger, and second circulating means for feeding to one of the polymerization stages a condensate formed by condensing, with a second heat exchanger different from the first heat exchanger, a gas removed from one of the polymerization stages.

Abstract: Process to separate particles from a particles-containing gas stream, by subjecting the particles-containing gas stream to a centrifugal separation step, wherein the particles-containing gas stream is separated in a gas rich flow and a particles-rich flow and wherein the particles-rich flow is cooled from a temperature in the range from 600 to 800° C. to a temperature in the range from 200 to 450° C. before it is subjected to a second separation step, wherein particles are separated from the particles-rich flow.

Abstract: A plant for the heat treatment of solids containing iron oxide includes a fluidized bed reactor. The reactor includes at least one gas supply tube at least partly surrounded by an annular chamber in which a stationary annular fluidized bed is located, and a mixing chamber being located above the upper orifice region of the at least one gas supply tube. The gas flowing through the at least one gas supply tube entrains solids from the stationary annular fluidized bed-into the mixing chamber when passing through the upper orifice region of the at least one gas supply tube.

Abstract: A plant for the heat treatment of solids containing iron oxide. The plant includes a reactor including a fluidized bed reactor. The reactor includes a gas supply system disposed in the reactor, a stationary annular fluidized bed which at least partly surrounds the gas supply system, and a mixing chamber. The gas supply system is configured so that gas flowing through the gas supply system entrains solids from the stationary annular fluidized bed into the mixing chamber.

Abstract: The process and apparatus converts ethylene in a dilute ethylene stream that may be derived from an FCC product to heavier hydrocarbons. The catalyst may be an amorphous silica-alumina base with a Group VIII and/or VIB metal. The catalyst is resistant to feed impurities such as hydrogen sulfide, carbon oxides, hydrogen and ammonia. At least 40 wt-% of the ethylene in the dilute ethylene stream can be converted to heavier hydrocarbons.

Abstract: A plant for the heat treatment of solids containing titanium includes a fluidized bed reactor. The reactor includes at least one gas supply tube being at least partly surrounded by an annular chamber in which a stationary annular fluidized bed is located, and a mixing chamber being located above the upper orifice region of the gas supply tube. The gas flowing through the gas supply tube entrains solids from the stationary annular fluidized bed into the mixing chamber when passing through the upper orifice region of the gas supply system. The plant further includes a solids separator downstream of the reactor. The solids separator includes a solids conduit leading to the annular fluidized bed of the reactor.

Abstract: A preferred embodiment of a system for loading catalyst and/or additives into a fluidized catalytic cracking unit includes a bin for storing at least one of the catalyst and/or additives, and a loading unit in fluid communication with the storage bin and the fluidized catalytic cracking unit on a selective basis. The loading unit is capable of being evacuated so that a resulting vacuum within the loading unit draws the catalyst and/or additive from the bin. The loading unit is also capable of being pressurized so that the catalyst and/or additive is transferred from the loading unit to the fluidized catalytic cracking unit.

Abstract: A particulate material processing apparatus has a vessel, a processing tank, and a dispersing member. The vessel has a charging port for charging a particulate material into the vessel. The processing tank receives the particulate material charged from the charging port. The processing tank is shaped so as to narrow towards the bottom. At least the lower part of the processing tank is made of a gas-permeable material that allows the process gas for processing the particulate material to pass through. The dispersing member is disposed below the charging port. The dispersing member disperses and flattens the particulate material on the processing tank.

Abstract: One exemplary embodiment can be a fluid catalytic cracking system. The fluid catalytic cracking system can include a reaction zone including a riser having a top and a bottom adapted to receive spent catalyst at a first elevation and regenerated catalyst at a second elevation. Typically, the first elevation is lower than the second elevation. Additionally, the fluid catalytic cracking system can include a gas distributor contained near the bottom of the riser in communication with a hydrocarbon feed.

Abstract: Hydrocarbon feed to a catalytic reactor can be heat exchanged with flue gas from a catalyst regenerator. This innovation enables recovery of more energy from flue gas thus resulting in a lower flue gas discharge temperature. As a result, other hot hydrocarbon streams conventionally used to preheat hydrocarbon feed can now be used to generate more high pressure steam.

Abstract: A circulating fluid bed reactor such as that used in fluid coking processes has a circular dense bed reaction section above the reactor base where the fluidizing gas is injected and a plurality of frusto-conical baffles in the dense bed reaction section, each of which depends downwardly and radially inwards from the reactor wall to a lower, inner edge defining a central aperture. The baffles are preferably provided with downcomers which permit downward flow of solids and upward flow of gas through the baffles.

Abstract: A pneumatic conveying system for conveying hydrated lime is provided with ambient air for the pneumatic conveying system from a scrubber that removes carbon dioxide from the ambient air used in the conveying system. The scrubber includes a bed of hydrated lime through which ambient air is passed, to react carbon dioxide in the air with the hydrated lime in a reaction that forms limestone and water. The air that has passed through the fluidized bed, which is essentially carbon dioxide free, is also passed through a filter to remove particles suspended in the carbon dioxide free air. The carbon dioxide free air from the filter is provided to the pneumatic conveying system. The use of carbon dioxide free air ensures that the hydrated lime being transported in the conveying system will not react in the various conduits and ducts of the pneumatic conveying system to cause problems.

Abstract: In a fluidized bed device 3 with a fluidized bed 2 of a bed material provided in a fluidized bed vessel 1 by a gas, the fluidized bed vessel 1 has a charge nozzle 4 connected to an upstream end of the vessel 1 in a direction of flow of the bed material; a charge port 4a of the charge nozzle 4 has a width equal to a width of the fluidized bed 2. The fluidized bed vessel 1 has a discharge nozzle 5 connected to a downstream end of the vessel 1 in the direction of flow of the bed material; a discharge port 5a of the discharge nozzle 5 has a width equal to the width of the fluidized bed 2.

Abstract: A method of processing a fluid and/or a particulate material, the method comprising the steps of: (a) introducing the particulate material into a chamber; (b) providing a flow of fluid into said chamber for entraining the particulate material; and (c) removing processed fluid and/or particulate material from the chamber; wherein the chamber comprises a processing zone having a substantially circular transverse cross-section, the fluid flow being introduced into the processing zone at an angle of between 10° and 75° with respect to a tangent of the substantially circular transverse cross-section of the processing zone to establish a fluid flow following a substantially helical path in the processing chamber.

Abstract: A spouted bed device of the present invention includes a cylinder which extends vertically; a closing plate which closes a top end of the cylinder; a decreasing diameter member which is formed at a bottom end of the cylinder, has an inside diameter that decreases progressively downward, and has a gas inlet orifice at a bottom end thereof; and a gas discharge nozzle which passes through the cylinder from an inside surface to an outside surface thereof and which discharges gas from a treatment zone enclosed by a top surface of the decreasing diameter member, a bottom surface of the closing plate and the inside surface of the cylinder. The gas discharge nozzle is provided above a spouted bed which is formed within treatment zone.

Abstract: An apparatus for withdrawing solids from a fluidized bed reactor comprises a venturi tube connected to the stem end of a funnel-shaped distribution plate, and a center jet pipe enclosed within the venturi, wherein a jet stream of feed gas is delivered above the venturi throat. Preferably, the distribution plate is equipped with multiple horizontally- or downwardly-oriented grid holes through which the feed gases flow and enter the fluidized bed, which holes may be covered by metal plates to prevent solids from weeping through grid holes and falling into the plenum below the distribution plate. The venturi is preferably engineered to be readily removable from the rest of the gasifier reactor for repair or replacement. Also provided is a fluidized bed reactor comprising the above apparatus.

Abstract: Two zone (11, 12; 21, 22; 31, 32; 41, 42) fluidized bed reactor (10, 20, 30, 40), wherein the upper zone (11, 21, 31, 41) presents a different section than the lower zone (12, 22, 32, 42). In one of the two zones (11, 12; 21, 22; 31, 32; 41, 42), a zone of reducing atmosphere is created and, in the other zone, a zone of oxidising atmosphere is created. In a preferred embodiment, the section of the upper zone (11, 21, 31, 41) is larger than that of the lower zone (12, 22, 32, 42), creating a reducing atmosphere in the upper zone (11, 21, 31, 41) and an oxidising atmosphere in the lower zone (12, 22, 32, 42). Rows of flow distributor tubes exist in the upper zone (11, 21, 31, 41) to avoid the appearance of dead zones.

Abstract: Embodiments of the present invention relate to measuring and controlling static in a gas phase reactor polymerization. In particular, embodiments relate to monitoring carryover static in an entrainment zone during gas phase polymerization to determine the onset of reactor discontinuity events such as chunking and sheeting. Embodiments also relate to monitoring carryover static to determine the need for effective additions of continuity additives that minimize reactor static activity and thereby preventing discontinuity events.

Abstract: Apparatus suited for removing carbon dioxide from gases are disclosed. The apparatus may employ bodies having a photocatalytic film. Associated methods and compositions are also disclosed.

Abstract: A system for converting fuel is provided and includes a first reactor comprising a plurality of ceramic composite particles, the ceramic composite particles comprising at least one metal oxide disposed on a support, wherein the first reactor is configured to reduce the at least one metal oxide with a fuel to produce a reduced metal or a reduced metal oxide; a second reactor configured to oxidize at least a portion of the reduced metal or reduced metal oxide from the said first reactor to produce a metal oxide intermediate; a source of air; and a third reactor communicating with said source of air and configured to regenerate the at least one metal oxide from the remaining portion of the solids discharged from the said first reactor and the solids discharged from the said second reactor by oxidizing the metal oxide intermediate.

Abstract: An apparatus (10) for surface treating particulate material (M) with surface treatment particles (S) includes a substantially cylindrical body (12) having a top (18), bottom (16) and sidewall (14). A mixing chamber (42) is defined within the body (12). At least one injector inlet (36) and at least one process air inlet (32) are in communication with the mixing chamber (42). At least one outlet (34) is in fluid communication with the mixing chamber (42).

Abstract: Systems and methods for treating a fluid with a body are disclosed. Various aspects involve treating a fluid with a porous body. In select embodiments, a body comprises ash particles, and the ash particles used to form the body may be selected based on their providing one or more desired properties for a given treatment. Various bodies provide for the reaction and/or removal of a substance in a fluid, often using a porous body comprised of ash particles. Computer-operable methods for matching a source material to an application are disclosed. Certain aspects feature a porous body comprised of ash particles, the ash particles have a particle size distribution and interparticle connectivity that creates a plurality of pores having a pore size distribution and pore connectivity, and the pore size distribution and pore connectivity are such that a first fluid may substantially penetrate the pores.

Abstract: A process and apparatus for gas phase polymerization of olefins in a fluidized bed reactor are disclosed. The process and apparatus employ a vertically oriented fines ejector in order to reduce fouling and reactor downtime.

Abstract: [Problems] To provide a treatment method having excellent purification effect, in which impurities having high ionicity in a silica powder can be removed in a short time, a apparatus thereof, and a purified silica powder. [Means for Solving the Problems] A purification method of a silica powder comprises: making a silica powder into a fluid state; contacting a purified gas to the silica powder in the fluid state at high temperature; and thereby removing impurity components of the silica powder. In the method, the silica powder in the fluid state is positioned in a magnetic field region. Further, the silica powder is contacted with the purified gas, while applying voltage to the silica powder by an electric field generated by moving of the silica powder. Preferably, the silica powder in a fluid state is positioned in the magnetic region of 10 gausses or more, and contacted with the purification gas at a temperature of 1000° C. or more.

Abstract: A catalyst includes a carrier body and a catalytic portion carried by the carrier body. The catalytic portion includes a plurality of distinct layers of catalytic material, which layers may be deposited through atomic layer deposition techniques. The catalyst may have a selectivity for the conversion of alkanes to alkenes of over 50%. The catalyst may be incorporated in a reactor such as a fluidized bed reactor or a single pass reactor.

Abstract: Disclosed is a method to safely terminate a runaway reaction within a reaction vessel, comprising: sensing an increase in pressure in the reaction vessel, opening a barrier blocking a flow path into the reactor, wherein the barrier opening is achieved via a mechanical response to the sensed increase in pressure, and injecting a kill agent into the reaction vessel via the opened flow path, thereby terminating the reaction. Also disclosed is a system for performing the method. The system functions without an external electrical source and is therefore compliant with ASME standards.

Abstract: The present invention relates to a high-pressure fluidized bed reactor for preparing granular polycrystalline silicon, comprising (a) a reactor tube, (b) a reactor shell encompassing the reactor tube, (c) an inner zone formed within the reactor tube, where a silicon particle bed is formed and silicon deposition occurs, and an outer zone formed in between the reactor shell and the reactor tube, which is maintained under the inert gas atmosphere, and (d) a controlling means to keep the difference between pressures in the inner zone and the outer zone being maintained within the range of 0 to 1 bar, thereby enabling to maintain physical stability of the reactor tube and efficiently prepare granular polycrystalline silicon even at relatively high reaction pressure.

Abstract: Fluidized bed reactor systems and distributors are disclosed as well as processes for producing polycrystalline silicon from a thermally decomposable silicon compound such as trichlorosilane. The processes generally involve reduction of silicon deposits on reactor walls during polycrystalline silicon production by use of a silicon tetrahalide.

Abstract: A process for producing a carbon nanomaterial, including fluidizing a carbon raw material, a catalyst and a fluidizing material in a fluidized bed reactor to produce the carbon nanomaterial, wherein the fluidizing material is a carbon material. A carbon nanomaterial production system for producing a carbon nanomaterial including a fluidized bed reactor for fluidizing a car-bon raw material, a catalyst and a fluidizing material to carry out the reaction thereof, a carbon raw material feeding device for feeding the carbon raw material to the fluidized bed reactor, a catalyst feeding device for feeding the catalyst to the fluidized bed reactor, and a recovering device for recovering the produced carbon nanomaterial from the fluidized bed reactor, wherein a part of the recovered carbon nanomaterial is transferred to the catalyst feeding device and used as the fluidizing material.

Abstract: The present invention relates to a system for the separation of suspensions of spent catalysts and hydrocarbons formed in an FCC unit with multiple ascending flow reaction tubes, comprising interconnections between each of the ascending flow reaction tubes and the separator vessel, each interconnection also comprises two sections. The outside sections of the separator vessel are inclined and are connected to a single vertical section, which penetrates into the interior of the separator vessel, and which has at its lower end an open device for draining the spent catalyst from the suspensions separated in this sector. In the same vertical section, at the end of its internal part at the separator vessel, a series of two sets of cyclones are installed, the first set containing cyclones without sealing legs, and the second set containing conventional cyclones of the first stage.

Abstract: Provided is a fuel gasification equipment capable of effectively utilizing a CO2 gas finally separated from a product or combustible gas such as H2 and CO for supply of a solid fuel to a gasification furnace, enabling stable supply of the solid fuel to the gasification furnace. The equipment has CO2 gas separation/circulation means for separating CO2 gas from the gasification gas produced in the gasification furnace 2 and introducing the separated CO2 gas to a supply system supplying the solid fuel to the gasification furnace 2.

Abstract: In order to produce granules granulometrically polidispersed in a very little range, a fluid bed granulation process of the type comprising the steps of preparing a fluid bed of seeds (S1) of the substance to be granulated, having a free surface (P) substantially horizontal; and feeding a continuous flow (L) of a fluid comprising a growth liquid, provides in the fluid bed for a continuous vortex (V) with a substantially horizontal axis, in which an upper zone (Z1) of seeds wetting and evaporation of possible solvent contained in the flow (L) and a lower zone (Z2) of solidification/consolidation of the growth liquid are identified.

Abstract: The gas-phase fluidized-bed reactor conducting reaction by feeding a gas, through a gas-distribution plate located at the lower part of a reaction vessel, into a fluidized bed formed on the gas-distribution plate, wherein the reaction vessel is made up so as to have a narrowed part at a specified position of the gas flow passage above the gas-distribution plate, and the fluidized bed is formed in the area from below the narrowed part to above the narrowed part. The gas-phase fluidized bed rector of the present invention allows manufacturing polymers having excellent homogeneity of polymer structure in gas-phase polymerization.