Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J4/00—Feed or outlet devices; Feed or outlet control devices
  • B01J4/001—Feed or outlet devices as such, e.g. feeding tubes
  • B01J4/004—Sparger-type elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/1818—Feeding of the fluidising gas
  • B01J8/1827—Feeding of the fluidising gas the fluidising gas being a reactant
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/1836—Heating and cooling the reactor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
  • B01J8/44—Fluidisation grids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/01—Processes of polymerisation characterised by special features of the polymerisation apparatus used
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/34—Polymerisation in gaseous state
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00017—Controlling the temperature
  • B01J2208/00106—Controlling the temperature by indirect heat exchange
  • B01J2208/00168—Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles
  • B01J2208/00176—Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles outside the reactor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00017—Controlling the temperature
  • B01J2208/00106—Controlling the temperature by indirect heat exchange
  • B01J2208/00265—Part of all of the reactants being heated or cooled outside the reactor while recycling
  • B01J2208/00274—Part of all of the reactants being heated or cooled outside the reactor while recycling involving reactant vapours
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00796—Details of the reactor or of the particulate material
  • B01J2208/00938—Flow distribution elements

Definitions

• TITLE “FLUIDIZED-BED REACTOR FOR THE GAS-PHASE
• the present invention relates to a fluidized-bed reactor for the gas-phase polymerization olefins and a process of preparing an olefin polymer.
• Gas-phase polymerization processes are economical processes for the preparation of polyolefins such as homopolymers of ethylene or propylene or copolymers of ethylene or propylene with other olefins.
• Fluidized-bed reactors for carrying out such processes have been known for a long time. These reactors contain a bed of polymer particles which is maintained in a fluidized state by an upward flow of a fluidizing gas.
• Customary reactors comprise, inter alia, a reactor space in the form of an inner chamber of a vertical cylinder. These reactors have a recycle gas line, in which coolers for removing the heat of polymerization, a recycle gas compressor and, if desired, further elements such as a cyclone for removing fine polymer dust are installed. Monomers consumed by the polymerization reaction are normally replaced by adding make-up gas to the recycle gas stream.
• T o achieve a homogeneous distribution of the fluidizing gas in the bed of growing polymer particles
• a gas distribution grid sometimes also called gas fluidization grid or distribution plate.
• Such a gas distribution grid is a device provided with openings which dispense into the bed a gas stream introduced under the grid itself. The grid also acts as support for the bed when the supply of gas is cut off.
• the gas distribution grid can be configured as a perforated or porous plate, sometimes in combination with an upstream flow divider. It is possible to arrange roof-shaped deflector plates above the openings in the distributor plate, as for example disclosed in EP 0 697 421 A1 , or to cover the openings with a cap as described in EP 0600414 A1 .
• the geometry of the gas distribution grid may also deviate from a plate.
• EP 0 088 638 A2 discloses a gas distributor for a fluidized- bed reactor which has a double cone-body.
• WO 2008/074632 A1 describes a gas distribution grid which has the form of an inverted cone.
• the object of the present invention is to provide a fluidized-bed reactor and a process of preparing an olefin polymer that allow the drawbacks of the known art to be at least partially overcome, and which are, at the same time, simple and inexpensive to implement.
• FIG. 1 is schematic and side view of a fluidized-bed reactor in accordance with the invention
• figure 2 is a plan view of the part of figure 1 with some details removed for clarity;
• figure 3 is a lateral cross-section of a part of the fluidized-bed reactor of figure 1 ;
• figure 4 is a front cross-section of a detail of figure 3;
• figure 5 is a lateral cross-section of the detail of figure 4.
• Suitable olefins also include those in which the double bond is part of a cyclic structure which can have one or more ring systems. Examples are cyclopentene, norbornene, tetracyclododecene or methylnorbornene or dienes such as 5-ethylidene-2- norbornene, norbornadiene or ethylnorborna- diene. It is also possible to polymerize mixtures of two or more olefins.
• the fluidized-bed reactor 1 is in particular suitable for the homopolymerization or copolymerization of ethylene or propylene and is especially preferred for the homopolymerization or copolymerization of ethylene.
• Preferred comonomers in propylene polymerization are up to 40 wt.% of ethylene, 1 -butene and/or 1- hexene, preferably from 0.5 wt.% to 35 wt.% of ethylene, 1-butene and/or 1- hexene.
• comonomers in ethylene polymerization preference is given to using up to 20 wt.%, more preferably from 0.01 wt.% to 15 wt.% and especially from 0.05 wt.% to 12 wt.% of C3 -Cs-1 -alkenes, in particular 1-butene, 1-pentene, 1- hexene and/or 1 -octene.
• the polymerization is carried out in the presence of an inert gas such as nitrogen or an alkane having from 1 to 10 carbon atoms such as methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane or n-hexane or mixtures thereof.
• an inert gas such as nitrogen or an alkane having from 1 to 10 carbon atoms such as methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane or n-hexane or mixtures thereof.
• nitrogen or propane as inert gas, if appropriate in combination with further alkanes, is advantageous.
• the polymerization is carried out in the presence of a C3-C5 alkane as polymerization diluent and most preferably in the presence of propane, especially in the case of homopolymerization or copolymerization of ethylene.
• the reaction gas mixtures within the reactor additionally comprise the olefins to be polymerized, i.e. a main monomer and one or more optional comonomers.
• the reaction gas mixture has a content of inert components from 30 to 99 vol.%, in particular from 40 to 95 vol.%, and especially from 45 to 85 vol.%.
• reaction gas mixture may further comprise additional components such as antistatic agents or molecular weight regulators like hydrogen.
• the components of the reaction gas mixture may be fed into the gas-phase polymerization reactor or into the recycle gas line in gaseous form or as liquid which then vaporizes within the reactor or the recycle gas line.
• catalysts of the Ziegler type comprise a compound of titanium or vanadium, a compound of magnesium and optionally an electron donor compound and/or a particulate inorganic oxide as a support material.
• Catalysts of the Ziegler type are usually used in the presence of a cocatalyst.
• cocatalysts are organometallic compounds of metals of Groups 1 , 2, 12, 13 or 14 of the Periodic Table of Elements, in particular organometallic compounds of metals of Group 13 and especially organoaluminum compounds.
• Preferred cocatalysts are for example organometallic alkyls, organometallic alkoxides, or organometallic halides.
• the fluidized-bed reactor of the present disclosure is operated at pressures of from 0.5 MPa to 10 MPa, advantageously from 1 .0 MPa to 8 MPa and in particular from 1.5 M Pa to 4 M Pa.
• the polymerization is advantageously but not necessarily carried out at temperatures of from 30 °C to 60 °C, particularly advantageously from 65 °C to 125 °C, with temperatures in the upper part of this range being preferred for preparing ethylene copolymers of relatively high density and temperatures in the lower part of this range being preferred for preparing ethylene copolymers of lower density.
• the gas recycle line 8 is configured to feed a fluidizing gas, which comprises a recycled part (taken from the inner chamber 2) and fresh olefins monomers (added along the gas recycle line 8), to the lower portion 3 of the inner chamber 2.
• the gas distribution grid 7 comprises a plurality of openings, that are configured to allow the passage of the fluidizing gas from the lower portion 3 to the upper portion 4 of the inner chamber 2 and comprise a plurality of first openings 11 located at more than 30 mm (in particular, at more than 40 mm; more in particular, at more than 80 mm) from the inner surface 6 of the lateral wall 5 and second openings 1 T located at less than 30 mm (in particular, at less than 20 mm; more in particular, less than 5 mm) from the inner surface 6 of the lateral wall 5.
• first openings 11 located at more than 30 mm (in particular, at more than 40 mm; more in particular, at more than 80 mm) from the inner surface 6 of the lateral wall 5
• second openings 1 T located at less than 30 mm (in particular, at less than 20 mm; more in particular, less than 5 mm) from the inner surface 6 of the lateral wall 5.
• the fluidized-bed reactor 1 comprises a lateral support 12, which extends (in a loop) along the inner surface 6 in contact with the inner surface 6 (and - at least partially - supports the gas distribution grid 7).
• the gas distribution grid 7 has a peripheral edge 13, which is positioned (at least) partially on (in particular, rests on) and in contact with the lateral support 12.
• the lateral support 12 has apertures 14, each of which is positioned at under a corresponding second opening 1 T and is configured to allow the passage of the fluidizing gas from the lower portion 3 to the upper portion 4 of the inner chamber 2 through the corresponding second opening 1 T. This ensures, at the same time, sufficient mechanical stability for the grid 7 without, at the same time, hindering the passage through the openings.
• the lateral support 12 has a width (measured from the inner surface 6 towards the center of the inner chamber 2) of at least 2 cm (in particular, at least 3 cm). More precisely but not necessarily, such a width (measured from the inner surface 6 towards the center of the inner chamber 2) is up to 6 cm (in particular, up to 4 cm).
• the apertures 14 are at least as big as the openings.
• the apertures 14, have a length of at least 40 mm (in particular, at least 50 mm; more in particular at least 70 mm; in particular up to 200 mm; more in particular up to 150 mm; even more in particular up to 100 mm).
• the apertures 14 are complete interruptions (gaps) of the lateral support 12.
• the apertures 14 are open - not delimited - towards the center of the inner chamber 2.
• the lateral support 12 is completely absent - not even partially present at the apertures 14 (a first stretch of the lateral support 12 ends just upstream from - before - an aperture 14 and a second stretch thereof starts just downstream from - after - such an aperture 14).
• the openings are formed in such a way that the flow of the fluidizing gas after having passed the openings is substantially parallel to a plane of the gas distribution grid 7 (in particular, tangential to the gas distribution grid 7; more in particular, substantially horizontal).
• the openings are slots.
• the width of the slots (openings) is more than their height (in particular, more than the double of their height).
• the openings are at least 3 mm wide (in particular, the width is in the direction from the inner surface 6 towards the center of the inner chamber 2). In addition or alternatively the openings are at most 10 cm wide (in particular, at most 5 cm wide).
• the openings comprise groups of openings aligned one with respect of the others (in particular, radially with respect to an axis of the inner chamber 2).
• the openings of one group are aligned one with respect of the others (radially with respect to an axis of the inner chamber 2).
• the fluidized-bed reactor 1 comprises an upper wall 15, which delimits a top of the inner chamber 2 and is connected to the lateral wall 5; and a lower wall 16, which delimits a bottom of the inner chamber 2 and is connected to the lateral wall 5.
• the gas recycle line 8 is configured to convey the recycled part of the fluidizing gas from the upper portion 4 of the inner chamber 2 through the upper wall 15 and the fluidizing gas through the lateral wall 5 to the lower portion 4.
• the fluidized-bed reactor 1 further comprises a polymer discharge pipe 17, which comprises an upper opening 18 integrated into the gas distribution grid 7.
• the upper opening 18 of the polymer discharge pipe 17 is arranged in the center of the gas distribution grid 7. More in particular, the polymer discharge pipe 17 is configured to discharge the polymer produced inside the upper portion 4.
• the discharge pipe 17 comprises regulation means 21 , such as a discharge valve, configured to adjust the mass flow rate of polymer discharged from the reactor 1.
• the opening of the regulation means 21 are continuously adjusted, so as to keep constant the height of the fluidized polymer bed inside the reactor.
• the discharge pipe 17 may be made of a uniform diameter, but preferably comprises more sections having decreasing diameters in the downward direction.
• the regulation means 21 are preferably placed in the area of (at) a restriction between a section of higher diameter and a section of lower diameter as shown in Fig. 1.
• the gas recycle line 8 is provided with (a compressor 19 and) a heat exchanger 20, which is configured to reduce the heat of the recycled part.
• an olefin polymer comprising homopolymerizing an olefin or copolymerizing an olefin and one or more other olefins (in particular, at temperatures of from 20 to 200 °C; in particular, at a pressures of from 0.5 to 10 MPa) in the presence of a polymerization catalyst, wherein the polymerization is carried out in the fluidized-bed reactor 1 as above disclosed.

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• 2023
  • 2023-09-08 EP EP23768521.9A patent/EP4587171A1/de active Pending
  • 2023-09-08 WO PCT/EP2023/074719 patent/WO2024056538A1/en not_active Ceased
  • 2023-09-08 JP JP2025512984A patent/JP2025527862A/ja active Pending
  • 2023-09-08 CN CN202380064018.5A patent/CN119836323A/zh active Pending
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