Method for preparing a shell-type catalyst

0001The invention relates to a method for producing a Coated catalyst in which a non-porous inorganic carrier material with low surface of less than 80 m² per g measured by the BET method with a catalytically active shell is provided.

0002Metals, preferably noble metals, are bound to a carrier in elemental form or as oxides in many technical The method used for catalysis. The catalyst support one can use porous or non-porous materials.

0003In the impregnation of carrier materials with the aqueous Metal salt solutions, followed by reduction of the salt , the metal on the carrier in the form of a shell, which the carrier completely envelops, are deposited. From these coated catalysts is known to inter alia Selective hydrogenations and oxidation reactions with Oxygen in the gas phase are particularly suitable.

0004One application of particular interest here includes the selective hydrogenation of acetylene, in particular the Purification of hydrogen chloride gas stream within the Oxychlorierungsprozesskreislaufes for the preparation of Vinyl chloride.

0005Vinyl chloride is either purely thermally or in the presence of catalysts at elevated temperature of 1,2-dichloroethane with elimination of hydrogen chloride produced. After separation of the main amount of the vinyl chloride falls to a hydrogen chloride gas, which normally contains up to 3000 Vppm acetylene. Before returning said hydrogen chloride in the oxychlorination is required, in an intermediate stage, the interfering Acetylene of the gas mixture to the greatest possible extent remove. This takes place by catalytic hydrogenation, the essential requirement as far as possible the Distance of acetylene (Restacetylengehalt <30 Vppm) thereof by selective hydrogenation to the is recyclable oxychlorination of ethylene.

0006The process conditions for the purification of Hydrogen chloride gas stream described in EP 0052271 B1 and US 4,388,278 described in detail. Usually, with a significant excess of hydrogen in a temperature range of 120-180 ° C in Pressure ranges 6-20 bar abs. hydrogenated.

0007For the cleaning of the hydrogen chloride gas stream by selective Hydrogenation of acetylene contained in it come packed bed catalysts for use. It is about preferably palladium-containing catalysts. catalyst formulations on alumina for this application known but in their performance potential / Selectivity and stability restricted.

0008In patent DE 30 37 047 C2 is a fixed bed catalyst described, which is characterized in that the Catalyst by impregnating silicon carbide as Support material with a solution of a palladium salt, and drying and reducing the palladium salt with Hydrogen is produced. This catalyst is on a comparatively expensive supporting material prepared.

0009EP-O 576 944 A1 discloses by depositing a Alloy by PVD (physical vapor deposition) and / or chemical vapor deposition (CVD) on a mold body produced coated catalysts.

0010As support nonporous moldings are made of glass, Quartz glass, ceramics, titania, zirconia, Alumina, aluminum silicates, borates, Stealit, Magnesium silicate, silica, silicates, metal, Carbon, eg., Graphite or mixtures of these Materials in question. The force applied to the mold body Alloy layer contains at least one metal preferably is very susceptible to oxidation, such as silicon, Aluminum, zirconium or titanium. The layer thickness is Range from 100 nm to 50 microns.

0011Finally, EP 0755718 A1 describes a method for the production of loaded non-porous support materials, wherein not porous inorganic support materials abrasion resistant coating with metal and / or metal oxide let by highly dilute aqueous solutions at least a metal compound on the heated mold body applies, so that the water can evaporate immediately, and then at an elevated temperature, if necessary, calcined.

0012From DE 32 00 483 A1 is a method for producing silica-shaped body, in which one to an inorganic base material is a mixture of soluble and not applying soluble silica. The resulting moldings can be used as a carrier for find different catalyst materials application.

0013It is of the described application Hydrogen chloride gas treatment by selective Acetylene hydrogenation also described a catalyst which as a carrier material silica used (Chem-Ing.-Tech. 59 (1987) No. 8, S. 645-647). This catalyst is, as the other formulations, with respect to its Performance of (space velocity load) limited.

0014Starting from this prior art, it was an object the invention provides a method for producing a Schalenkatalysatos of the aforementioned type is available to provide that a simple way to create a Catalyst enables the example for said Application at elevated space velocities (GHSV > 3000 / h) can be used.

0015This object is achieved by a generic A process for preparing a shell catalyst, which the features of the characterizing part of the Claim 1 having. Expedient refinements of Method of the invention are described in the main claim, made dependent claims under protection.

0016Characterized in that, in the preparation of a coated catalyst wherein a non-porous inorganic carrier material, which has a BET surface area of ​​less than 80 m² per g which is provided with a catalytically active shell will, initially at the first step, a suspension of at least one water-soluble noble metal compound and a water-insoluble substantially Coating compound is dried onto the carrier material and then at the second step, the resulting cupped coated substrate in a reductive effective gas flow is activated, it is possible in simple and not readily foreseeable to a product create, which meets the aforementioned objectives.

0017In particular, it can considered surprising are that it is possible by the method of the invention is a non-porous support material in a single Operation with active and Coating Material simultaneously to coat. These surface active advantageous Structure according to the invention in a surprisingly simple Way available.

0018In this case, the preparation method of the invention differ and the previously known prior Technology disclosed manufacturing processes for coated catalysts considerably. Thus, in the EP 0,576,944 the Deposition of a noble metal alloy by PVD or CVD in achieved a high vacuum. For this purpose are relatively expensive technologies and equipment needed.

0019EP 0755718 A1 separates water-soluble metal compounds or metal salts wherein the metal content is limited to 2 wt .-%, in a moving bed on Carrier material from, the boundary condition exists that ensuring the immediate evaporation of the solvent water have to be. In contrast to the process known from EP 0755718 The method according to the present invention Suspensions of a water soluble material and a substantially water-insoluble material on a nonporous support dried up. This is a Another structure of the coated catalyst thus available probably, in any case, however, the coated Coated catalyst particularly easily available.

0020The method according to the invention under the coated non-porous inorganic Support materials include particularly advantageous granules, Moldings or ceramic support. Good results can be on with ceramic carriers, particularly those Aluminum oxide and / or silicate-based, can be achieved. furthermore are low the most diverse aluminum silicates, Alumina itself, silicon carbide contents of Alumina and silica, zirconia, with or without Contents of alumina and silica, titanium dioxide with and without aluminum oxide and silicon dioxide, For example, corundum, feldspar, mica, steatite, Ceramic stone tools, glass, quartz, etc.

0021In a particular embodiment, the method is the Invention is characterized in that as carrier materials Moldings of glass, quartz, ceramic, silicon dioxide, Alumina, graphite, shape coals, metal or steatite be used. Of these, are of enhanced Interest moldings based on SiO₂ and / or Al₂O₃,

0022Of great interest as carrier materials in the process according to the invention are also SiO₂granulates of different to name grits.

0023The outer shape of the carrier of the present invention produced coated catalyst usable materials may be varied in nature. So it can be to Granules, shaped bodies in the form of spheres, tablets and / or act strands. In an expedient variant the inventive process are support materials in the form of Hohlextrudaten, Vollextrudaten, balls, Granules, tablets and / or extrudates used. The Support materials can also serve as extrudate, as Hollow extrudate, a tube section, as rings or used lens shape.

0024In a particular variant granules shaped Materials coated in the process of the invention. Good to very good cup preparations were particular to ceramic materials (aluminosilicates) under the obtained invention.

0025Depending on the desired end use of the coated catalysts may be rollable carrier materials beneficial. In this case balls are particularly preferred.

0026The particle to be coated the Support materials is in itself not critical and can vary over a wide range. The carrier have preferably particle diameter in the range of 0.5 to 50 mm. Particularly preferably, the range 1 is to 20 mm.

0027In one variant of the range of> 1 mm is quite particularly preferred. Also particle diameter of less 0.5 mm are sometimes driven in dependence on the Application useful.

0028The BET surface area according to the invention with a shell to verse Henden inorganic carrier materials is lower than 80 m²/ G, which close to a non-porous support leaves. More desirably, it is when support materials having a BET surface area of ​​<30 m²/G, preferably <10 m²be / g used.

0029In addition the BET surface of the support material is also the Pore ​​volume in a particularly advantageous modification of the The inventive method of some importance. So is featuring an advantageous variant of the method the invention characterized in that carrier materials having a Pore ​​volume <0.5 ml / g are used. particularly appropriate is to support materials with a pore volume <0.1 ml / g to use.

0030The non-porous inorganic support materials According to the invention produced coated catalyst come in useful embodiment of a very low Fe₂O₃-Salary. Preferred are Fe₂O₃-contents of <0.5 wt .-% based on the weight of the support material.

0031In the production of a shell catalyst according to the invention in a first step, together with the Coating material a water-soluble noble metal compound dried onto the support material. "Water-soluble" in the context of the invention are Compounds, when calculated in a concentration as metal, of 0.01, preferably 0.05 wt .-% in water can be solved from 30 ° C.

0032In water-soluble precious metal compounds comprise, preferably water-soluble compounds of Ru, Rh, Pd, Ag, Os, Ir, Pt and / or Au.

0033Preferably, oxides, hydroxides, carbonates, Halides, nitrates, organic acid salts and / or other common complex compounds used, which the Precious metal ions. The soluble Noble metal compounds can be u. U. also to acids, such as hexachloro palladium solutions act. Preferably used according to the invention Noble metal salt solutions that contain palladium. Especially preferred are palladium salt solutions such as palladium chloride and palladium nitrate solutions.

0034Basically, the precious metal content of the method of Invention employed soluble precious metal compounds Although random and depends on the one hand, for example, For availability, but it is particularly emphasized, that the method of the invention in a particularly advantageous variant is characterized in that the water-soluble noble metal compound as an aqueous solution containing the precious metal compound, calculated as metal, is used in a concentration of> 1 wt .-%. Still more preferably it is, when noble metal solutions having a Content of> 5% noble metal, calculated as metal, be used. Solutions which have a content of <1% have precious metal, would in unusually large quantities be applied. From this it would be a prolonged Auftrocknungszeit result to a corresponding To achieve precious metal content in the catalyst shell.

0035As already stated, it is in the soluble Noble metal compounds used according to the invention are preferably those which, in a concentration in terms of metal, of at least 0.01 wt .-% in water can be solved from 30 ° C.

0036In contrast, it concerns with the substantially water-insoluble coating compounds that simultaneously with the water soluble precious metal compound to the Support material be dried to such Compounds in in bevozugter embodiment of a Concentration, calculated as metal, of less than can be 4 wt .-% dissolved in water of 30 ° C.

0037These coating compounds have therefore a poor water solubility, resulting in the suspension results, which is applied in the first step.

0038The inventively employable Coating Materials include finely divided inorganic compounds are metal-oxide type used. Preferably SiO₂. Al₂O₃, TiO₂ and / or ZrO₂, Particularly preferred among these are SiO₂ and Al₂O₃Is very particularly preferably SiO₂,

0039To create the shell of the present invention can be prepared Coated catalyst are preferably materials with an average Agglomeratgrößenbereich to 15 microns, preferably having an agglomerate size in the range of 2 to 10 microns used. is very particularly preferred to use of finely divided silicas with a Agglomeratgrößenbereich 3-7 microns.

0040Larger agglomerates / particles are generally for Preparation is not particularly advantageous since it causes by their size, not a homogeneous, firmly adhering, can form abrasion-resistant shell.

0041The metal oxides used preferably have a Surface area ranging from 50 to 500 m²/ G, preferably 100 to 300 m²/ G and a tamped density (according to DIN / ISO 787 / 11XI, JISK 5101/18) in the range of 10 to 800 g / l, preferably 50 to 500 g / l.

0042More desirably, silicas, which the corresponding said surface and tamped densities exhibit.

0043Under the use of said metal oxides prepared shell catalysts are referred to it Scanning electron microscope images recorded very homogeneous, show Scholl education except Macro bays (in the aufgecoateten materials can accumulate) on the support surface also no Cracking. At very high magnification to recognize a largely homogeneous grain structure.

0044The shell thickness produced in accordance with the invention can shell catalysts rather over a wide range be specifically controlled. Preferably it is in the range from 0.1 to 20 microns. Particularly preferred ranges are from 0.5 to 10 microns. Extremely advantageous is when the Shell thickness> 1 .mu.m.

0045The ratio of water-soluble noble metal compound and substantially insoluble in water Coating compound in the aufzutrocknenden to the carrier material Suspension is variable over a wide range. Particularly preferred is a method of the invention, the is characterized in that the water-soluble Precious metal compound and the water substantially insoluble coating compound, each based on the Metal content, in a weight ratio of noble metal compound Coating to compound ranging from 0.1: 1 to 1 used:. 5 It is especially advantageous Variant in which the noble metal compound and the Coating compound in a weight ratio in the range are used 1: from 0.5: 1 to. 2

0046Further advantageous is when the noble metal compound, based on the total weight of the coated catalyst, in a weight ratio, calculated as metal, in the range from 0.0001: 1 to 0.02: 1 is used.

0047Moreover, it is of particular importance when the Coating compound, based on the total weight of Coated catalyst and calculated as metal, in a Weight ratio in the preferred range of 0.0005: 1 1 is used: to 0.005.

0048The content of metal, in particular palladium or platinum the coated catalyst as in accordance with the method of Invention can be produced, is preferably at most 1 wt .-% metal, preferably in the range between 0.1 and 0.5 wt .-% metal. Metal contents, in particular palladium contents, below 0.1 wt .-% are not useful because of the Catalyst in a row abrasion loads in real use could lose precious metal under process conditions and thus too short with too low precious metal content would have service life. Higher precious metal content than 1 wt .-% are not particularly useful, since this in the present coated catalysts as a result of to unnecessary very small surface of the substrate Location accumulations of the precious metal under liability reduction could result and thus also no great Performance potential is recorded. The content of coating materials, in the producible according to the invention Shell preparations is preferably in the range of 0.05 to 1 wt .-%, expressed as metal. particular preference The amount is 0.05 to 0.5 wt .-%, expressed as Metal, based on the total catalyst weight. at this scale Extension of the preferred fine Coating Materials results in a surprisingly good adhesion effect.

0049According to the second step of the process according to the invention the shell formulations were reductively in a effective gas flow to the activated coated catalysts implemented. This treatment consists in the selective A reaction of the alloy components with a gas or Gas mixture at a higher temperature.

0050In particular, it is preferred that a hydrogen containing gas stream is used for activation.

0051To improve the adhesion between the carrier and aufzutrocknendem Material, it is possible the person skilled in the common adhesion promoters, eg., water glass, add. These are added to the suspension and the the same process step applied to the support.

0052It is equally possible that the suspension extra Doping compounds be added to certain Influences the activity / selectivity of the catalyst to enable.

0053The invention also provides the use of in accordance with the procedure described herein available Coated catalysts for selective hydrogenation of acetylene in gas streams. Specifically vorteilig is the invention herstellare coated catalyst in gas streams in Purification of hydrogen chloride gas in the vinyl chloride process used.

0054Preferably, therefore, an invention within the Shell catalyst prepared by drying on a Suspension of a noble metal salt solution, preferably Palladium salt solution with a finely divided material, preferably silica and subsequent reduction with a reductively effective, preferably containing hydrogen Gas obtained, the low on support materials Interface is based and which is characterized by a high activity and selectivity at high space velocities up 8000 / h, preferably in the range 2000-6000 / h, in which Purification of hydrogen chloride gas stream by selective Hydrogenation of acetylene contained in it to ethylene distinguished.

0055The process conditions are particularly useful:<sl><li>Temperature range 100 - 200 ° C, preferably 100-160 ° C; </li><li>Pressure range for hydrogen chloride gas stream (process pressure) 1 to 15 bar absolute, preferably 6 -. 12 bar, depending on the Process pressure for the oxychlorination;</li><li>Dwell time 2 - 15 sec. (At operating conditions and Empty pipe);</li><li>Hydrogen: acetylene ratio 1: 1 to 6: 1, preferably 2: 1 to 4: 1;</li><li>The invention by way of examples below will Reference to the accompanying figures 1-3 further explained.</li></sl>

0056Show the pictures<dl tsize="8"><dt>Fig. 1:</dt><dd>Sales / selectivity / abrasion behavior of Inventive coated catalyst in Depending on the coating material ratio;</dd><dt>Fig. 2:</dt><dd>Sales / selectivity of the catalyst in accordance with Comparative Example 1 depending on the Space velocity;</dd><dt>Fig. 3:</dt><dd>Sales / selectivity of the invention Catalyst according to Example 2 (coated catalyst) depending upon the Space velocity;</dd></dl><sl><li>Fig. 1 shows the dependence of the performance potential (Turnover / Selekltivität) and the abrasion of a coated catalyst according to the invention, prepared with a Palladium salt solution on a SiO₂Granulate grit 3-5 mm, of the content of silica having an average Agglomerate size of 7 um. The conversion and selectivity data were determined in a laboratory test apparatus at 130 ° C. The test gas used had the following composition:</li><li>Hydrogen 0.5% / 0.2% acetylene / 99.3% nitrogen.</li></sl>

0057The figure clearly shows that at levels of> 0.25 Wt .-% silica a significant increase abrasion occurs without substantial conversion and selectivity gains can be reported. From silica contents of 0.1 .-% are already significant sales increases in increased space velocity with respect to a The catalyst is prepared without addition of silica to recorded. Thus is the most preferred Silica component, based on the total catalyst weight of the exemplary catalyst in 0.1 - 0.3 wt .-% of silica preferably used.

0058A coated catalyst described particularly preferred composition from 0.1 to 1 wt .-% Pd and 0.1 to 1 wt .-% silica on a non-porous SiO₂-Carrier the grain size 3-5 mm, and the low surface of &lt;1m²/ G characterized by a very high activity and Selectivity at space velocities up to 8000 / h, preferably 2000 - 6000 / h, in the example applied selective hydrogenation of acetylene in a hydrogen chloride gas stream under the described process conditions from.

0059The increased activity of the invention Catalyst is a result of the improved Fine distribution of the preferably applied Silica shell integrated precious metal. The silica effects a fine distribution effect these promotional Surface enlargement. In contrast, when porous carrier materials impregnated the additional superficial carrier reactive centers an additional Potential for undesirable side reactions.

0060owns The Schalenkatalystor the present invention an expanded activity potential. For example selected application in the hydrogen chloride gas cleaning be high Acetylenumsätze up in a GHSV range of 8000 / h. The selectivities to ethylene lie over 60%.

0061In the preparation of the coated catalysts of present invention, the drying of the Suspension of noble metal salt, preferably a Palladium salt, and particulate coating material, preferably Silica, giving as a final training a homogeneous shell in a moving bed; ie the Suspension of noble metal salt and preferably silica is thoroughly mixed together with the carrier and the Solution water under external heating removed by distillation.

0062By the production method and the formation of a superficial peel are also various doping and adhesion-promoting additives easily possible with the appropriate Effects on the shell and modification the performance. Preferred doping additives are known from the literature (eg DLTrimm, Design of Industrial Catalysts, Elsevier Scientific Publ. Comp., 1980 p.229 ff).

Preparation of the catalyst on an industrial scale

<b>Comparative Example 1:</b>

-Standardkatalysator Without Kieselsäurezusatz-

0063The preparation of this catalyst is in a moving Bed. Etched and acid washed SiO₂-Granules is presented in the preparation drum. Among continuously übergleitetem nitrogen stream is the appropriate amount (0.15 wt .-% Pd based on Catalyst weight) of palladium chloride solution in the Drum added. By supplying pressure steam (140 ° C) in the outer shell of the preparation drum is the Palladium salt solution with a rotating drum to the support dried up. The reduction is carried out by passing over a excess hydrogen gas stream in periodically rotating preparation drum. The Wasserstoffgastrom is a nitrogen gas stream in subsequent Cooling replaced.

0064The catalyst obtained by this preparation methodology has a gray-glossy extremely thin outer noble metal shell of &lt;1 micron.

<b>Example 2:</b>

- Production of the coated catalyst -

0065In deviation from the standard preparation of the catalyst in Example 1 of the coated catalyst is by submitting 0.5 t dry SiO₂Granulate started. Thereafter, the 0.25 wt .-% of the catalyst corresponding amount of dry silica submitted in the preparation drum.

0066It is appropriate to 0.15 wt .-% of the catalyst Amount of palladium nitrate solution in the preparation drum added. After an action under nitrogen blanketing in rotating drum closes Drying up to at 140 ° C in Example. 1 The reduction is carried out by supplying forming gas (5% hydrogen in Nitrogen) in the bed of the dried Catalyst.

0067The catalyst obtained is deep black and matt.In Table 1 shows the in Preparation Example 1 and 2 described catalysts in terms of their physical properties compared.<tables><table><tgroup cols="3"><tbody><row><entry align="center"><b>Parameter:</b></entry><entry align="center"><b>The catalyst of Comparative Example 1 -Standardkatalysator-</b></entry><entry align="center"><b>A catalyst according to Example 2 -Schalenkatalysator-</b></entry></row><row><entry align="left">Pd content [wt .-%]</entry><entry align="center">0.15</entry><entry align="center">0.15</entry></row><row><entry align="left">Silica content [wt .-%]</entry><entry align="center">0</entry><entry align="center">0.25</entry></row><row><entry align="left">Appearance</entry><entry align="center">gray / glossy</entry><entry align="center">Matt black</entry></row><row><entry align="left">Output [wt .-%] ASTM D 4058-87</entry><entry align="center">0,2 - 0,3</entry><entry align="center">0.4 to 0.5</entry></row><row><entry align="left">BET surface area [m²/G]</entry><entry align="center">no adsorption</entry><entry align="center">&lt;1</entry></row><row><entry align="left">CO adsorption [10^-2 ml / g]</entry><entry align="center">0.3</entry><entry align="center">1.25</entry></row></tbody></tgroup></table></tables>

<b>Performance Comparison:</b>

Example I

Comparative Experiments 1 and 2

0068The described under Comparative Example 1 and Example 2 Catalysts was in a pilot test plant on her back tested conversion and selectivity potential.

0069The pilot test system is configured as a bypass reactor system to a existing hydrogenation unit for cleaning the Chlorvasserstoffgasstroms within the vinyl chloride production plant attached, so that an up to 2000 ppm acetylene containing real hydrochloric gas flow directly to the Catalysts can be applied. There are two Reactors installed in parallel, so that in a reactor Reference catalyst can be tested while in the parallel reactor introduced new developments can be. Thus, a direct comparison with fluctuating plant conditions and qualities of Hydrogen chloride possible. The reactors are designed to that they can be filled with 2 liters of catalyst. they are heated by heating coils with pressure steam. Hydrogen is flexibly metered with a rotameter and each reactor has centered on a temperature measurement ( in the catalyst bed), which for temperature control can be used.

0070The maximum zuleitbare flow of hydrogen chloride amounts per reactor 16 Nm³/H. The reaction gas after the Reactors is separately a gas chromatographic Analysis supplied.

<b>performance Comparison</b>

0071Those described in Comparative Example 1 and Example 2 Catalysts were several months in the pilot test facility tested under varying parameters. claim the primary benchmarking was, inter alia, the fixing of the Turnover and exploring the corresponding Space velocity as a direct measure of performance. The comparable settings are shown in Table 2 and 3 collected.<tables><table><tgroup cols="3"><tbody><row><entry namest="1" nameend="3">Setting I:</entry></row><row><entry align="center"><b>Compare Size:</b></entry><entry align="center"><b>The catalyst of Comparative Example 1 -Standardkatalysator- reactor A</b></entry><entry align="center"><b>A catalyst according to Example 2 -Schalenkatalysator- reactor B</b></entry></row><row><entry align="left">Runtime [weeks]</entry><entry align="right">8th</entry><entry align="right">8th</entry></row><row><entry align="left">temperature</entry><entry align="right">130</entry><entry align="right">130</entry></row><row><entry align="left">H₂ : C₂H₂-Relationship</entry><entry align="right">2</entry><entry align="right">2</entry></row><row><entry align="left">sales C₂H₂ [%]</entry><entry align="right">90</entry><entry align="right">91</entry></row><row><entry align="left">Selectivity to C₂H₄ [%]</entry><entry align="right">51</entry><entry align="right">63</entry></row><row><entry align="left"><b>GHSV [1 / h]</b></entry><entry align="right"><b>750</b></entry><entry align="right"><b>4500</b></entry></row></tbody></tgroup></table></tables><tables><table><tgroup cols="3"><tbody><row><entry namest="1" nameend="3">Setting II:</entry></row><row><entry align="center"><b>Compare Size:</b></entry><entry align="center"><b>The catalyst of Comparative Example 1 -Standardkatalysator- reactor A</b></entry><entry align="center"><b>A catalyst according to Example 2 -Schalenkatalysator- reactor B</b></entry></row><row><entry align="left">Runtime [weeks]</entry><entry align="right">12</entry><entry align="right">12</entry></row><row><entry align="left">temperature</entry><entry align="right">130</entry><entry align="right">135</entry></row><row><entry align="left">H₂ : C₂H₂molar ratio</entry><entry align="right">2</entry><entry align="right">2</entry></row><row><entry align="left">sales C₂H₂ [%]</entry><entry align="right">70</entry><entry align="right">73</entry></row><row><entry align="left">Selectivity to C₂H₄ [%]</entry><entry align="right">52</entry><entry align="right">61</entry></row><row><entry align="left"><b>GHSV [1 / h]</b></entry><entry align="right"><b>1500</b></entry><entry align="right"><b>6000</b></entry></row></tbody></tgroup></table></tables>

0072The illustrated in Tables 2 and 3 performance comparison fixed sales clearly shows the increased Performance potential of the coated catalyst according to this Invention in the application of Hydrogen chloride gas cleaning. The coated catalyst can in 4 - 6 times higher space velocities in used simultaneous ethylene selectivity profit will.

<b>Sales / selectivity behavior</b>

0073The conversion and selectivity behavior of in Example 1 and Catalysts 2 were described in various detects space velocities and in Table 4 collected. <tables><table><tgroup cols="6"><tbody><row><entry namest="1" nameend="6">Default: Temperature (bed center): 130 ° C; H₂ : C₂H₂ Molar ratio = 2</entry></row><row><entry namest="1" nameend="3" align="center"><b>The catalyst of Comparative Example 1 - A reactor Standardkatalysator-</b></entry><entry namest="4" nameend="6" align="center"><b>A catalyst according to Example 2 - Schalenkatalysator- reactor B</b></entry></row><row><entry align="center">GHSV</entry><entry align="center">Sales of C₂H₂ [%]</entry><entry align="center">Selectivity to C₂H₄ [%]</entry><entry align="center">GHSV</entry><entry align="center">Sales of C₂H₂ [%]</entry><entry align="center">Selectivity to C₂H₄ [%]</entry></row><row><entry align="left">750</entry><entry align="right">90</entry><entry align="right">52</entry></row><row><entry align="left">1000</entry><entry align="right">82</entry><entry align="right">57</entry></row><row><entry align="left">1500</entry><entry align="right">70</entry><entry align="right">52</entry></row><row><entry align="left">2250</entry><entry align="right">60</entry><entry align="right">64</entry><entry align="right">2250</entry><entry align="right">100</entry><entry align="right">39</entry></row><row><entry align="left" /><entry align="right" /><entry align="right" /><entry align="right">4500</entry><entry align="right">91</entry><entry align="right">63</entry></row><row><entry align="left">6000</entry><entry align="right">16</entry><entry align="right">60</entry><entry align="right">6000</entry><entry align="right">73</entry><entry align="right">61</entry></row></tbody></tgroup></table></tables>

<b>Graphical representation in Fig.2 and 3</b>

0074The sales / selectivity behavior of the inventive Coated catalyst shows that over the Standard catalyst (prior art), far Higher space velocities can be applied without revenue dips occur. In high GHSV range from 4000 / h results in very advantageous, preferred sales and Selectivity constellations.