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
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
  • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
  • B01J8/0496—Heating or 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
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/02—Apparatus characterised by being constructed of material selected for its chemically-resistant properties
• • 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
  • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
  • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
  • B01J8/0403—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal
  • B01J8/0423—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal through two or more otherwise shaped beds
  • B01J8/0438—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal through two or more otherwise shaped beds the beds being placed next to each other
• • 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
  • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
  • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
  • B01J8/0446—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical
  • B01J8/0449—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more cylindrical beds
  • B01J8/0453—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more cylindrical beds the beds being superimposed one above the other
• • 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
  • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
  • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
  • B01J8/0446—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical
  • B01J8/0476—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more otherwise shaped beds
  • B01J8/048—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more otherwise shaped beds the beds being superimposed one above the other
• • 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
  • 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
  • B01J2208/00212—Plates; Jackets; Cylinders
• • 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
  • B01J2208/00548—Flow
• • 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
  • B01J2208/00548—Flow
  • B01J2208/00557—Flow controlling the residence time inside the reactor vessel
• • 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
  • B01J2208/00628—Controlling the composition of the reactive mixture
• • 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
  • B01J2208/02—Processes carried out in the presence of solid particles; Reactors therefor with stationary particles
  • B01J2208/023—Details
  • B01J2208/024—Particulate material
  • B01J2208/025—Two or more types of catalyst
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/02—Apparatus characterised by their chemically-resistant properties
  • B01J2219/0204—Apparatus characterised by their chemically-resistant properties comprising coatings on the surfaces in direct contact with the reactive components
  • B01J2219/0236—Metal based
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/02—Apparatus characterised by their chemically-resistant properties
  • B01J2219/025—Apparatus characterised by their chemically-resistant properties characterised by the construction materials of the reactor vessel proper
  • B01J2219/0277—Metal based
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/02—Apparatus characterised by their chemically-resistant properties
  • B01J2219/025—Apparatus characterised by their chemically-resistant properties characterised by the construction materials of the reactor vessel proper
  • B01J2219/0277—Metal based
  • B01J2219/0286—Steel
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/02—Apparatus characterised by their chemically-resistant properties
  • B01J2219/025—Apparatus characterised by their chemically-resistant properties characterised by the construction materials of the reactor vessel proper
  • B01J2219/0277—Metal based
  • B01J2219/029—Non-ferrous metals
• • 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
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/12—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of actinides
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall

Definitions

• the present invention relates to a process for the production of chlorine by catalytic gas phase oxidation of hydrogen chloride with oxygen, wherein the reaction is carried out on 18 to 60 catalyst beds connected in series under adiabatic conditions, and a reactor system for carrying out the process.
• the catalyst bed is tempered via the outer wall, and according to DE 10 2004 006 610 A1, the fluidized bed is heated by means of a heat exchanger arranged in the bed.
• the effective heat removal of this process faces problems of non-uniform residence time distribution and catalyst wear, both of which result in a loss of revenue.
• thermostated tube bundle reactors are used which, especially in the case of large reactors, have a very complicated cooling circuit (WO 2004/052776 A1).
• EP 1 170 250 A1 has proposed the use of catalyst fillings in tube bundle reactors which have different activities in different regions of the cooled contact tubes. As a result, the progress of the reaction is slowed down so much that the resulting heat of reaction can be more easily removed via the wall of the catalyst tubes. A similar result should be achieved by the targeted dilution of the catalyst bed with inert material.
• a disadvantage of these solutions is that two or more catalyst systems must be developed and used in the catalyst tubes or that by using inert material, the reactor capacity is impaired.
• the catalysts used initially for the Deacon process for example supported catalysts with the active composition CuCl 2 , had only a low activity. Although the activity could be increased by increasing the reaction temperature, it was disadvantageous that the volatility of the active components at high temperature led to rapid deactivation of the catalyst.
• the oxidation of hydrogen chloride to chlorine is also an equilibrium reaction. The position of the equilibrium shifts with increasing temperature to the detriment of the desired end product.
• catalysts with the highest possible activity are used, which allow the reaction to proceed at low temperature.
• Known highly active catalysts are based on ruthenium.
• DE-A 197 48 299 describes supported catalysts with the active material ruthenium oxide or ruthenium mixed oxide.
• the content of ruthenium oxide is 0.1 wt .-% to 20 wt .-% and the average Particle diameter of ruthenium oxide 1.0 nra to 10.0 nm.
• the reaction is carried out at a temperature between 90 ° C and 150 ° C.
• ruthenium chloride catalysts containing at least one compound of titanium oxide or zirconium oxide, ruthenium-carbonyl complexes, ruthenium salts of inorganic acids, ruthenium-nitosyl complexes, ruthenium-amine complexes , Ruthenium complexes of organic amines or ruthenium-acetylacetonate complexes.
• the reaction is carried out at a temperature between 100 ° C and 500 ° C, preferably 200 ° C and 380 ° C.
• the catalyst is used in a fixed bed or in a fluidized bed.
• the oxygen source used is air or pure oxygen.
• the Deacon reaction remains an exothermic reaction and temperature control is also required in the application of such highly active catalysts.
• the inventors of the present invention have surprisingly found that it is possible to achieve the objects described above by carrying out the reaction on 18 to 60 catalyst beds arranged in series under adiabatic conditions.
• the process gas may in addition to oxygen and hydrogen chloride still have minor components, eg. As nitrogen, carbon dioxide, carbon monoxide or water.
• the hydrogen chloride can upstream production process, eg. As for the production of polyisocyanates, originate and other impurities, eg. B. phosgene.
• carrying out the process under adiabatic conditions on the catalyst beds means that substantially no heat is supplied to the catalyst from the outside in the respective catalyst beds nor is heat removed (with the exception of the heat which is supplied or removed by the reaction gas entering or leaving). , Technically, this is achieved by insulating the catalyst beds in a conventional manner.
• the individual catalyst beds are operated adiabatically, so they are in particular no means of heat dissipation in them are provided.
• the invention also includes the case in which the heat of reaction is removed, for example, by means of heat exchangers connected between the individual catalyst beds.
• catalyst bed is here an arrangement of the catalyst in all known forms, e.g. Fixed bed, fluidized bed or fluidized bed understood. Preferred is a fixed bed arrangement. This comprises a catalyst bed in the true sense, d. H. loose, supported or unsupported catalyst in any form and in the form of suitable packings:
• catalyst bed as used herein also encompasses contiguous areas of suitable packages on a support material or structured catalyst supports. These would be e.g. to be coated ceramic honeycomb carrier with comparatively high geometric surfaces or corrugated layers of metal wire mesh on which, for example, catalyst granules is immobilized.
• Stationary catalyst beds are preferably used in the new process.
• the reaction is carried out at 20 to 40, preferably 22 to 30 consecutive Katal ysatorbetten.
• a preferred further embodiment of the method is characterized in that the process gas mixture emerging from at least one catalyst bed is subsequently passed over at least one heat exchanger arranged downstream of the catalyst bed.
• the method is located after each catalyst bed at least one, preferably a heat exchanger, through which the exiting process gas mixture is passed.
• at least one heat exchanger is located behind at least one catalyst bed.
• at least one, more preferably in each case exactly one heat exchanger is located behind each of the catalyst beds, via which the gas mixture emerging from the catalyst bed is passed.
• the catalyst beds can either be arranged in a reactor or arranged divided into several reactors.
• the arrangement of the catalyst beds in a reactor leads to a reduction in the number of apparatuses used.
• individual ones of the series catalyst beds can be independently replaced or supplemented by one or more catalyst beds in parallel.
• the use of catalyst beds connected in parallel allows in particular their replacement or supplementation during ongoing continuous operation of the process.
• the process according to the invention preferably has 18 to 60 catalyst beds connected in series. Parallel and successively connected catalyst beds can in particular also be combined with one another. However, the process according to the invention particularly preferably has exclusively catalyst beds connected in series.
• the reactors which are preferably used in the process according to the invention can consist of simple containers with one or more thermally insulated catalyst beds, as described, for example, in Ullmann's Encyclopedia of Industrial Chemistry (Fifth, Completely Revised Edition, VoI B4, pages 95-104, pages 210-216) become. This means that it is possible, for example, to use single-stage or multistage fixed-bed reactors, radial-flow reactors or even shallow-bed reactors., However, tube bundle reactors are preferably not used because of the disadvantages described above, since heat is removed from the catalyst beds according to the invention , Such reactor types for receiving the catalyst beds are also unnecessary.
• the catalysts or the catalyst beds thereof are applied in a manner known per se to or between gas-permeable walls of the reactor.
• the empty tube velocity of the gas in the catalyst bed is preferably from 0.1 to 10 m / s in the case of the embodiment using a fixed bed.
• a molar ratio of between 0.25 and 10 equivalents of oxygen per equivalent of hydrogen chloride before entry into the catalyst bed is preferably used.
• the inlet temperature of the material entering a first catalyst bed gas mixture from 150 to 630 ° C, preferably 200-480 0 C.
• the hydrogen chloride and oxygen-containing feed gas stream can also be fed preferably only in front of the first catalyst bed. This has the advantage that the entire feed gas stream can be used for the absorption and removal of the heat of reaction in all catalyst beds. However, it is also possible to meter in hydrogen chloride and / or oxygen into the gas stream before one or more of the catalyst beds following the first catalyst bed as required. In addition, the temperature of the reaction can be controlled via the supply of gas between the catalyst beds used.
• the reaction gas is cooled after at least one of the catalyst beds used, more preferably after each of the catalyst beds used. This is what leads you to that
• Reaction gas through one or more heat exchangers which are behind the respective Catalyst beds are located.
• These may be the heat exchanger known to those skilled in the art, such as, for example, tube bundle, plate ring groove, spiral, finned tube, micro heat exchanger.
• steam is generated on cooling the product gas at the heat exchangers.
• the catalyst beds connected in series are operated at increasing or decreasing average temperature from catalyst bed to catalyst bed.
• the chlorine formed is separated off.
• the separation step usually comprises several stages, namely the separation and, if appropriate, recycling of unreacted hydrogen chloride from the product gas stream of the catalytic hydrogen chloride oxidation, drying of the obtained, essentially chlorine and oxygen-containing stream and the separation of chlorine from the dried stream.
• the separation of unreacted hydrogen chloride and water vapor formed can be carried out by condensation of aqueous hydrochloric acid from the product gas stream of hydrogen chloride oxidation by cooling. Hydrogen chloride can also be absorbed in dilute hydrochloric acid or water.
• the z. T. be entrained with the starting materials, the reaction again fed.
• the recirculated hydrogen chloride and / or oxygen are recycled in front of one or more of the catalyst beds and before, if necessary brought back to the inlet temperature by means of a heat exchanger.
• the cooling of the product gas and the warming-up of the recirculated hydrogen chloride and / or oxygen are carried out by passing the gas streams in counterflow through heat exchangers to one another.
• the new process is preferably operated at a pressure of 1 to 30 bar, preferably from 1 to 20 bar, more preferably from 1 to 15 bar.
• the temperature of the educt gas mixture is preferably before each of the catalyst beds of 150 to 630 ° C, preferably from 200 to 480 0 C, more preferably from 250 to 470 ° C.
• the gas mixture is preferably homogenized before entering the individual catalyst bed.
• the thickness of the flow-through catalyst beds can be chosen the same or different, and is suitably 1 cm to 8 m, preferably 5 cm to 5 m, particularly preferably 30 cm to 2.5 m.
• the catalyst is preferably used immobilized on a support.
• the catalyst preferably contains at least one of the following elements: copper, potassium, sodium, chromium, cerium, gold, bismuth, uranium, ruthenium, rhodium, platinum, and the elements of VIII. Subgroup of the Periodic Table of the Elements. These are preferably used as oxides, halides, or mixed oxides / halides, in particular chlorides or oxides / chlorides. These elements or compounds thereof can be used alone or in any combination.
• Preferred compounds of these elements include copper chloride, copper oxide, potassium chloride, sodium chloride, chromium oxide, bismuth oxide, uranium oxide, ruthenium oxide, ruthenium chloride, ruthenium oxychloride, rhodium oxide.
• the catalyst portion consists completely or partially of ruthenium and / or uranium or compounds thereof, more preferably the catalyst consists of halide and / or oxygen-containing uranium and / or ruthenium compounds.
• all or part of the catalyst portion is uranium oxides such as UO 3 , UO 2 , UO or the non-stoichiometric phases resulting from mixtures of these species such as U 3 O 5 , U 2 O 5 , U 3 O 7 , U 3 O 8 , U 4 ⁇ 9 .
• the carrier fraction may be wholly or partly composed of: titanium oxide, tin oxide, aluminum oxide, zirconium oxide, uranium oxide, vanadium oxide, ceria, chromium oxide, uranium oxide, silicon oxide, silica, carbon nanotubes or a mixture or compound of said substances, in particular mixed oxides such as silicon-aluminum oxides.
• Particularly preferred support materials are tin oxide, carbon nanotubes, uranium oxides such as UO 3 , UO 2 , UO or the non-stoichiometric phases resulting from mixtures of these species, such as U 3 O 5 , U 2 O 5 , U 3 O 7 , U 3 O 8 , U 4 O 9 ..
• the ruthenium-supported catalysts can be obtained, for example, by impregnation of the support material with aqueous solutions of RuCl 3 and optionally a promoter for doping.
• the shaping of the catalyst can take place after or preferably before the impregnation of the support material.
• the catalysts are suitable as promoters alkali metals such as lithium, sodium, potassium, rubidium and cesium, preferably lithium, sodium and potassium, more preferably potassium, alkaline earth metals such as magnesium, calcium, strontium and barium, preferably magnesium and calcium, particularly preferably magnesium, Rare earth metals such as scandium, yttrium, lanthanum, cerium, praseodymium and neodymium, preferably scandium, yttrium, lanthanum and cerium, more preferably lanthanum and cerium, or mixtures thereof.
• alkali metals such as lithium, sodium, potassium, rubidium and cesium, preferably lithium, sodium and potassium, more preferably potassium, alkaline earth metals such as magnesium, calcium, strontium and barium, preferably magnesium and calcium, particularly preferably magnesium, Rare earth metals such as scandium, yttrium, lanthanum, cerium, praseodymium and neodymium, preferably scandium, yt
• the shaped bodies can then be dried at a temperature of 100 to 400 ° C., preferably 100 to 300 ° C., for example under a nitrogen, argon or air atmosphere, and optionally calcined.
• the moldings are first dried at 100 to 150 ° C and then calcined at 200 to 400 ° C.
• the temperature of the catalyst in the catalyst beds is suitably in a range of 150 ° C to 800 ° C, preferably 200 0 C to 450 ° C, more preferably 250 ° C to 400 ° C.
• the control of the temperature in the catalyst beds is preferably carried out by at least one of the following measures:
• the catalysts or the supported catalysts may have any desired form, for. As balls, rods, Raschig rings or granules or tablets.
• composition of the catalysts in the catalyst beds used according to the invention may be identical or different. In a preferred embodiment, the same catalysts are used in each catalyst bed. However, it is also advantageous to use different catalysts in the individual catalyst beds. Thus, in particular in the first catalyst bed, when the concentration of the reaction products is still high, a less active catalyst can be used and in the further catalyst beds the activity of the catalyst can be increased from catalyst bed to catalyst bed.
• the control of the catalyst activity can also be carried out by dilution with inert materials or carrier material.
• 0.1 g / h to 10 g / h of chlorine preferably 0.5 g / h to 5 g / h of chlorine, can be prepared per 1 g of catalyst.
• the inventive method is thus characterized by high space-time yields, combined with a reduction of the apparatus sizes and a simplification of the apparatus or reactors.
• the educt for the process according to the invention is hydrogen chloride, which is e.g. is produced and adopted as by-product from the phosgenation of organic amines, especially diamines to isocyanates, in particular diisocyanates or the gas phase phosgenation of phenol to diphenyl carbonate.
• Oxygen can be supplied as pure oxygen or preferably in the form of an oxygen-containing gas, in particular air.
• the produced chlorine can be used, for example, for the production of phosgene and possibly recycled into connected production processes.
• the process is conducted such that a continuous exchange of a fixed bed catalyst takes place.
• unreacted educt gases are recycled back to the process.
• Unreacted educt gases are in particular hydrogen chloride and oxygen. The process is therefore operated as a cyclic process.
• the invention further provides a reactor system for reacting a gas containing hydrogen chloride and oxygen, at least containing feed lines for hydrogen chloride and oxygen or for a mixture of hydrogen chloride and oxygen and 18 to 60 thermally insulated catalyst beds connected in series.
• the reactor system may also comprise 20 to 40 or 22 to 30 catalyst beds.
• FIG. 2 shows a process according to the invention with 18 catalyst beds in an integrated reactor
• FIG. 1 shows a method according to the invention with 18 catalyst beds divided into separate reactors.
• the educt gases (1, 2) are mixed to gas mixture (3) and fed to the reactor.
• the reactors each comprise a catalyst bed (20).
• the product gases of the reactors (4) are passed through heat exchangers (30).
• the heat exchanger (30) comprises feeds (5) and discharges (6) of cooling medium.
• Fig. 1 it is symbolized that a repeat unit of reactor with catalyst bed (20) and heat exchanger (30) repeated 16 times in total, so that a total of 18 units are shown.
• the product gas mixture is finally subjected to a separation of substances (40) and separated into hydrogen chloride (7), oxygen (8), chlorine (9) and water (10). It is also possible to return unreacted hydrogen chloride gas (7) and oxygen gas (8) back to the reactors. This is not shown here.
• FIG. 2 shows a process according to the invention with 18 catalyst beds in an integrated reactor.
• the reactors each comprise a catalyst bed (20).
• the product gases of the reactors (4) are passed through heat exchangers (30).
• the heat exchanger (30) comprises feeds (5) and discharges (6) of cooling medium.
• FIG. 2 symbolizes that a repeat unit of reactor with catalyst bed (20) and heat exchanger (30) is repeated a total of 16 times, so that a total of 18 units are shown.
• the product gas mixture is finally subjected to a separation of substances (40) and separated into hydrogen chloride (7), oxygen (8), chlorine (9) and water (10). It is also possible to return unreacted hydrogen chloride gas (7) and oxygen gas (8) back to the reactors. This is not shown here.
• Examples 1 and 2 relate to the number of catalyst beds and the temperature profile of the process gas mixture when it reacts in the reaction zones according to the inventive method and is cooled again in downstream heat exchangers. Furthermore, the examples relate to the conversion of HCl obtained.
• the process gas mixture flowed through a total of 24 catalyst stages, ie through 24 reaction zones. After each catalyst stage there was a heat exchanger which cooled the process gas mixture before entering the next catalyst stage.
• the process gas used at the outset was a mixture of HCl (38.5 mol%), O 2 (38.5 mol%) and inert gases (Ar, Cl 2 , N 2 , CO 2 , totaling 23 mol%).
• the inlet pressure of the process gas mixture was 5 bar.
• the length of the catalyst stages, ie the reaction zones was uniformly 7.5 cm.
• the activity of the catalyst was adjusted to be the same in all catalyst stages. The procedure was carried out so that a load of 1, 2 kg of HCl per kg of catalyst and hour was achieved. There was no replenishment of process gas components before the individual catalyst stages.
• the total residence time in the plant was 2.3 seconds.
• the results are shown in FIG.
• the individual catalyst stages are listed on the x-axis, so that a spatial course of developments in the process is visible.
• the temperature of the process gas mixture is indicated on the left y-axis.
• the temperature profile over the individual catalyst stages is shown as a solid line.
• On the right y-axis the total conversion of HCl is indicated.
• the course of the conversion over the individual catalyst stages is shown as a dashed line.
• the inlet temperature of the process gas mixture before the first catalyst stage is about 340 ° C. Due to the exothermic reaction to chlorine gas under adiabatic conditions, the temperature rises to about 370 ° C, before the process gas mixture is cooled by the downstream heat exchanger again. The inlet temperature before the next catalyst stage is about 344 ° C. By exothermic adiabatic reaction, it rises again to about 370 0 C. The sequence of heating and cooling continues.
• the inlet temperatures of the process gas mixture upstream of the individual catalyst stages increase with increasing number of stages. This is possible since the amount of reactants capable of reacting in the later stages of the reaction is lower and accordingly the danger of a through exothermic reaction conditional leaving the optimum temperature range of the process decreases. Consequently, the temperature of the process gas mixture can be kept closer to optimal for the respective composition.
• the process gas mixture flowed through a total of 18 catalyst stages, ie through 18 reaction zones. After each catalyst stage there was a heat exchanger which cooled the process gas mixture before entering the next catalyst stage.
• the process gas used at the outset was a mixture of HCl (38.5 mol%), O 2 (38.5 mol%) and inert gases (Ar, Cl 2 , N 2 , CO 2 , totaling 23 mol%)
• the inlet pressure of the process gas mixture was 5 bar.
• the length of the catalyst stages, ie the reaction zones, was uniformly 15 cm in each case.
• the activity of the catalyst was adjusted to increase with the number of catalyst stages.
• the relative catalyst activities were as follows:
• the procedure was carried out to achieve a load of 1.12 kg of HCl per kg of catalyst per hour. There was no replenishment of process gas components before the individual catalyst calls. The total residence time in the plant was 3.5 seconds.
• On the left y-axis is the temperature of the Process gas mixture specified. The temperature profile over the individual catalyst stages is shown as a solid line.
• On the right y-axis the total conversion of HCl is indicated. The course of the conversion over the individual catalyst stages is shown as a dashed line.
• the inlet temperature of the process gas mixture before the first catalyst stage is about 350 ° C. Due to the exothermic reaction to chlorine gas under adiabatic conditions, the temperature rises to about 370 ° C, before the process gas mixture is cooled by the downstream heat exchanger again. The inlet temperature before the next catalyst stage is again about 350 ° C. By exothermic adiabatic reaction, it rises again to about 370 0 C. The sequence of heating and cooling continues.
• the inlet temperatures of the process gas mixture upstream of the individual catalyst stages increase more slowly with increasing number of stages than in the case of Example 1. Overall, the fluctuation range of the process gas temperatures is even lower.
• the desired lower activity of the catalyst in the early stages makes it possible to introduce the process gas mixture with a higher inlet temperature, without fear of undesired overheating. Consequently, the temperature of the process gas mixture can be kept closer to optimal for the respective composition.

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• 2008
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  • 2008-06-26 CN CN200880024532A patent/CN101687160A/zh active Pending
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