Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B7/00—Halogens; Halogen acids
  • C01B7/01—Chlorine; Hydrogen chloride
  • C01B7/03—Preparation from chlorides
  • C01B7/04—Preparation of chlorine from hydrogen chloride
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
• • 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
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/24—Stationary reactors without moving elements inside
• • 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
  • B01J8/005—Separating solid material from the gas/liquid stream
  • B01J8/0055—Separating solid material from the gas/liquid stream using cyclones
• • 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

Definitions

• the invention relates to a process for the production of chlorine by gas phase oxidation of hydrogen chloride in a fluidized bed reactor.
• the mass transfer in a fluidized bed and thus also the conversion of the reactants is significantly influenced, in particular, by catalyst particles of a size in the range from about 15 to 45 ⁇ m (compare Chemical Reaction Eng., Proceedings of the Fifth European / Second International Symposium on Chemical Reaction. , Amsterdam, 2, 3 and 4 May, 1972)
• catalyst particles in particular catalyst particles in the order of magnitude of about 15 to 45 microns particularly important for the mass transfer , with limited restraint.
• catalyst particles in the above-mentioned order of magnitude which are particularly important for the mass transfer and which are entrained with the product gas stream should be recycled back into the fluidized bed.
• smaller catalyst particles with an average particle size ⁇ 15 microns should be collected as much as possible in order to recover the expensive catalyst and to prevent them interfere in subsequent system components, in particular lead to coverings on heat exchanger tubes and possibly also to bonds. This finer fraction should not be recycled unchanged in the fluidized bed.
• the object is achieved by a process for the production of chlorine by gas phase oxidation of hydrogen chloride on a heterogeneous, particulate catalyst in a fluidized bed reactor, to obtain a product gas mixture in cyclones, which are arranged in the upper part of the fluidized bed reactor, of entrained catalyst particles is freed, comprising a cylindrical upper part with a tangential or spiral inlet for the product gas mixture, which tapers at its lower end via a conical part in a cyclone downcomer, and a central dip tube in the upper part of the cyclone for discharging the entrained catalyst particles freed product gas mixture , characterized in that one to seven cascades of two to five cyclones connected in series are used, the cyclones of the cascade, with the exception of the respective first cyclone, which is designed so that there in which at least 90% by weight of the entrained catalyst particles are deposited, each having a trickle valve at the lower end of the cyclone downcomer, comprising an angled pipe
• Fluidized bed reactors generally have an at least approximately rotationally symmetrical, in particular a cylindrical, geometry.
• the starting materials, hydrogen chloride and an oxygen-containing gas stream are fed to the fluidized-bed reactor from below via a gas distributor, in particular a perforated bottom or a bottom with gas distribution nozzles arranged therein, the process conditions being set such that a heterogeneous, particulate catalyst forms a fluidized bed.
• supported catalysts are preferably used which comprise one or more metal components on an oxidic support.
• Metal components are, for example, ruthenium or copper compounds.
• Alumina in particular ⁇ -aluminum oxide or ⁇ -aluminum oxide, zirconium oxide, titanium oxide or mixtures thereof can be used as oxidic supports.
• the catalysts based on ruthenium known from GB 1, 046,313, DE-A 197 48 299 or DE-A 197 34 412 can be used.
• the catalysts described in DE-A 102 44 996 are suitable based on gold, containing on a support 0.001 to 30 wt .-% gold, 0 to 3 wt .-% of one or more alkaline earth metals, 0 to 3 wt .-% of one or more alkali metals, 0 to 10 wt .-% of one or more rare earth metals and 0 to 10 wt .-% of one or more other metals selected from the group consisting of ruthenium, palladium, osmium, iridium, silver , Copper and rhenium, each based on the total weight of the catalyst.
• a ⁇ -alumina powder is preferably impregnated with an aqueous solution of ruthenium chloride hydrate corresponding to the water absorption of the support, then dried at 100 to 200 ° C. and finally calcined at 400 ° C. under an air atmosphere.
• the ruthenium content of the catalyst is preferably 1 to 5 wt .-%, in particular 1, 5 to 3 wt .-%.
• the process is preferably carried out as described in WO 2005/092488 by controlling the temperature distribution within the fluidized bed by arranging one or more heat exchangers in the fluidized bed in such a way that the temperature profile in the main flow direction, along the axis of rotation of the fluidized bed reactor, a temperature difference between the lowest and highest temperature of at least 10 Kelvin.
• the product gas mixture which leaves the fluidized bed at its upper end, entrains a part of the catalyst particles with it.
• one to seven cascades of in each case two to five cyclones connected in series are provided by the process according to the invention in the upper region of the fluidized-bed reactor.
• a cascade as usual, an arrangement of devices connected in series, in this case cyclones understood.
• Each cyclone comprises in the manner known to those skilled, a cylindrical upper part with a tangential or spiral inlet for the mixture to be separated, in this case the product gas mixture, wherein the cylindrical upper part tapers at its lower end via a conical part into a cyclone downcomer. Due to the tangential or spiral inlet, the product gas mixture to be separated is imparted with a spiral downward movement, the catalyst solid particles contained therein depositing on the walls of the cyclone and be discharged via the cyclone downfall pipe. The gas stream cleaned off in the cyclone leaves the same in its upper area via a central dip tube.
• At least one cascade of in each case two to five cyclones connected in series is used, the cyclone of each cascade flowing through first being designed such that at least 90% by weight of the entrained catalyst particles are precipitated therein.
• the cyclone design is carried out according to the manner known to the person skilled in the art, as a rule according to the model by Barth-Muschelknautz, in particular taking into account the pressure loss and the degree of separation, which primarily depend on the peripheral velocities inside the cyclone (see VDI Warmestlas, 8th edition, 1979, Lja1-Lja1 1).
• the cyclone of the one or more cascades, which is flowed through first, is in particular designed such that the cyclone downcomer is submerged in the fluidized bed. This prevents a bypass of product gas mixture via the cyclone downcomer, or ensures that the product gas mixture passes through the cyclone exclusively or almost exclusively via the tangential inlet.
• a baffle plate can be arranged below the lower end of the cyclone downcomer.
• one to four cyclones of each cascade are each equipped with a trickle valve at the lower end of the cyclone downcomers, each of which, as usual, has an angled pipe end and a loose, at an angle ⁇ to the vertical, which is different from 0, has suspended flap.
• the flap must lie completely on the angled, adjoining the cyclone downpipe lower pipe end; thus, this must be angled beyond the vertical position.
• the lower end of the cyclone downcomer is closed with a trickle valve to reduce or prevent gas bypass over it.
• the inventors have recognized that it is possible to design the flap so that the separated solid additionally seals the flap against a gas bypass, while at the same time ensuring that the cyclone is not flooded by separated solid matter. Contrary to the view held in the trade publication "Hydrocarbon Processing", May 2007, pp. 75-84 that the flap weight has no influence on the gas bypass, it was found that the torque of the flap, wherein the angle of attack of the flap to the vertical and enter the flap weight, in the above range of about 2 to 300 N / m 2 a minimal gas bypass and thus a minimal loss of expensive catalyst results.
• the angle ⁇ of the flap to the vertical is set in particular in a range between 1 and 5 ° and can vary in a relatively large range, from about 0.1 to 100 kg, because of the flap size depends, which in turn depends on the outlet opening of the tube.
• the flaps are designed so that they have a torque in the range between 10 and 200 N / m 2 , in particular in the range between 30 and 100 N / m 2 . More preferably, the flaps are designed so that they have an increasing torque with increasing position of the corresponding cyclone in the cascade. Preferably, one to five cascades of cyclones are used, in particular two to three cascades of cyclones.
• each cascade comprises two to three cyclones.
• identical cyclones can be used. In case of several cascades these can be identical to each other.
• the product gas stream which is already largely purified in one or more cascades of cyclones, can additionally be conducted via a filter arranged outside the fluidized-bed reactor. This may in particular be designed so that it retains catalyst particles with a diameter ⁇ 15 microns.
• nickel chloride which can form during the reaction, is retained in the external filter. The process is advantageously carried out under the injection of inert gas.
• Preferred is in the equipped with flaps cyclones - At the inner wall of the angled Rohrend Anlagenes, at the point A, where the extension of the center line of the cyclone downcomer pipe meets the inner wall and / or - at a point B, which is located downstream of the point A, and / or
• Inert gas sparging may be carried out at any of the three sites A to C alone or in any combination of sites A, B and C.
• a further advantage of inert gas flushing is that it is possible to check the function of a trickle valve via a differential pressure measurement between two gassing lines or a differential pressure measurement between a gassing line and the reactor head, since the pressure loss is a measure of the separation between the two measuring points Amount of solids is.
• FIG. 1 shows the schematic illustration of a preferred embodiment of a cyclone for use in the method according to the invention
• FIG. 2 shows a preferred embodiment of a trickle valve with representation of the suspension for the flap, with partial representation of the suspension for the flap in Figure 2A
• Figure 3 is a schematic representation of a plan view of a flap
• Figure 4 is a schematic representation of a pilot plant, the one to
• FIGS. 5 to 7 show the results of tests with the pilot plant shown in FIG. 4, with different flap weights.
• Figure 1 shows schematically a cyclone 1 with a cylindrical upper part 2 with tangential inlet 3 for the product gas mixture, which tapers via a conical part 4 to a cyclone downfall tube 5, with central dip tube 6 in the upper part of the cyclone for the discharge of entrained catalyst particles liberated product gas mixture, as well as with a trickle valve 7 at the lower end of the cyclone downcomer 5, comprising an angled pipe end 8, which is formed in two pieces in the preferred embodiment shown in the figure, as well as a loosely suspended at an angle ⁇ to the vertical flap 9th
• FIG. 2 shows an enlarged view of the lower end of a cyclone downpipe 5 with a Trickle Valve 7 adjoining it, which comprises an angled pipe end piece 8.
• a cyclone downpipe 5 with a Trickle Valve 7 adjoining it, which comprises an angled pipe end piece 8.
• an inlet pipe for inert gas is arranged by way of example.
• the angled pipe end 8 terminates at an angle ⁇ , the slightly, in the present example by 3 °, deviates from the vertical.
• a suspension device 10 for the flap not shown in Figure 2 (reference numeral 9 in Figure 1) is provided.
• FIG. 2A shows an enlarged view of the suspension device 10.
• Figure 3 shows the schematic representation of a preferred embodiment of a flap 9, with two exemplary openings 11 in the upper region of the flap 9, via which the flap 9 is suspended in corresponding suspension devices 10.
• Figure 4 shows the schematic representation of a pilot plant that simulates a cyclone downpipe 5 with trickle valve 7. About a solids dosage 12 solid is metered into the cyclone downcomer, the pressure maintenance 13 simulates the negative pressure in the cyclone downcomer and the separated solid is weighed on the balance 14.
• Figures 5 to 7 show the results of the embodiments, which were carried out on a pilot plant shown in Figure 4.
• test A and B the product is metered into the downpipe at a rate of 30 kg / h at a set and regulated vacuum of 850 mbar.
• a small amount of gassing of about 200 L / h is added via the gassing. The difference between the two tests lies in the flap or its weight.
• experiment A see diagram experiment A
• only the flap about 3 kg net weight
• the drop tube is thus empty after each opening and accordingly the amount of leakage gas is high.
• experiment C see diagram experiment C
• the particles are also metered in at 30 kg / h and gassed at about 200 L / h. From about 1 - 1, 5 h, the solid trickles out continuously but slowly out of the cyclone downpipe. During this time, there are no significant fluctuations in pressure or in the amount of leakage gas. This means that the particles held by the heavy flap in the cyclone downcomer seal the flap opening.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)

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• 2010
  • 2010-07-28 EP EP10737322A patent/EP2462054A1/de not_active Withdrawn
  • 2010-07-28 CN CN2010800390549A patent/CN102482082A/zh active Pending
  • 2010-07-28 KR KR1020127005860A patent/KR20120054616A/ko not_active Application Discontinuation
  • 2010-07-28 US US13/389,081 patent/US20120134913A1/en not_active Abandoned
  • 2010-07-28 JP JP2012523290A patent/JP2013500926A/ja not_active Withdrawn
  • 2010-07-28 BR BR112012002613A patent/BR112012002613A2/pt not_active IP Right Cessation
  • 2010-07-28 WO PCT/EP2010/060943 patent/WO2011015503A1/de active Application Filing

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