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  Selective hydrogenation process and catalystUSPTO Application #: 20060084830Title: Selective hydrogenation process and catalyst Abstract: 0.1-5 0-25 Group IIA & B 0-1.5 0-2.5 Group IA 0-5 0-10 Ag 0.01-0.1 0.005-0.2 Pd 0.0-0.6 0-1 Cu 4-11 3-15 Ni wt. % wt. % Component Preferably Range of component A supported catalyst for selective hydrogenation of acetylenes comprising 3-15 wt. % Ni promoted with 0.005-0.2 Pd on a support. The catalyst is prepared by depositing nickel promoted with palladium on a support, containing one or more optional elements from copper, silver, Group IA (Li, Na, K, Rb, Cs, Fr) and Group IIA (Be, Mg, Ca, Sr, Ba, Ra) and B(Zn, Cd,) of the periodic table of elements and characterized as: (end of abstract) Agent: Kenneth H. Johnson - Houston, TX, US Inventor: J. Yong Ryu USPTO Applicaton #: 20060084830 - Class: 585259000 (USPTO) Related Patent Categories: Chemistry Of Hydrocarbon Compounds, Adding Hydrogen To Unsaturated Bond Of Hydrocarbon, I.e., Hydrogenation, Hydrocarbon Is Contaminant In Desired Hydrocarbon, Hydrogenation Of Diolefin Or Triple Bond The Patent Description & Claims data below is from USPTO Patent Application 20060084830. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to the selective removal of acetylenic compounds from hydrocarbon streams using specific Ni-based catalysts and the process of making the catalysts. The process is particularly useful in cleaning up MAPD (methyl acetylene and propadiene) and acetylene in crude mixed olefin streams or phenylacetylene in crude styrene streams by selective hydrogenation in the presence of the Ni-based catalyst. [0003] 2. Related Information [0004] Acetylenic impurities such as acetylene, methyl acetylene, vinyl acetylene, ethyl acetylene, and 2-methyl-1-buten-3-yne are found in various crude mixed C.sub.2-C.sub.5 streams, for example in the manufacture of olefins such as ethylene, propylene, butadiene and isoprene. These acetylenic impurities need to be removed with a minimum loss of the useful olefinic materials, i.e., ethylene, propylene, butenes, butadiene, isoprene and the like. [0005] For example, 1,3-butadiene is an important raw material used to produce various polymers such as butadiene-styrene copolymer. One of the processes for producing 1,3-butadiene is co-production of various olefins by steam cracking of petroleum fractions. The crude mixed C.sub.4 stream from a steam cracker is selectively hydrogenated to partially remove C.sub.4 acetylenic compounds. The selectively hydrogenated stream is sent to the 1,3-butadiene recovery unit where solvent extractive distillation techniques are used to separate 1,3-butadiene from the rest of components in the mixed stream. Solvent extractive distillation is expensive to operate and energy consumption is intensive. [0006] Complete removal of C.sub.4 acetylenic compounds in the stream with high recovery of 1,3-butadiene is highly desirable to reduce the production cost of 1,3-butadiene and produce a premium quality product for polymer production. However, formerly it was technically impossible to completely remove C.sub.4 acetylenes in crude mixed streams by selective hydrogenation without unacceptably high loss of 1,3-butadiene due to over-hydrogenation of 1,3-butadiene. Therefore, an improved inexpensive process via a highly active and selective catalyst is highly desirable to produce premium quality 1,3-butadiene without paying a penalty for high loss of 1,3-butadiene due to over-hydrogenation. [0007] The preferred technique for the purification in commercial practice is the selective hydrogenation of acetylenic compounds over hydrogenation catalysts. Supported Pd, Ni, Cu and Co catalysts are known as useful for the hydrogenation of acetylenes (Handbook of Commercial Catalysts, pp. 105-138, Howard F. Rase, CRC Press, 2000). The most preferred catalysts in prior commercial applications of selective hydrogenation of acetylenes are palladium-based catalysts such as Pd, Pd/Pb, Pd/Ag or Pd/Au on a support such as alumina and the copper catalysts on a support such as alumina. Pd catalysts were the most preferred catalysts because of high activity and higher selectivity compared with other known metal catalysts. [0008] However, palladium-based catalysts are not selective enough to completely remove C.sub.4 acetylenes without an unacceptable amount of 1,3-butadiene loss due to over-hydrogenation. Another inherent problem of palladium-based catalysts is the loss and migration of palladium due to the formation of soluble Pd complex compounds by the reaction of Pd atoms on the catalyst surface with vinyl acetylene, if the hydrogenation is carried out with a liquid phase. Silver and gold have been used to minimize the loss of palladium and reduce catalytic polymerization of acetylenic compounds. [0009] The copper-based catalysts are very selective so that the recovery of 1,3-butadiene from the mixed stream is very high compared with palladium-base catalysts. The activity of copper catalysts is very low compared with palladium-based catalysts, and a large volume of catalyst and large reactor are required. Also because the deposition of heavy carbonaceous materials on the catalyst occurs quickly, frequent regeneration of catalysts necessitates multiple reactors. [0010] Ni catalysts in any form are very active catalysts for selective hydrogenation of acetylenes and dienes. According to R. S. Mann et al. (Can. J. Chem. 46, p. 623, 1968), Ni and Ni--Cu alloy catalysts are effective for methyl acetylene hydrogenation. The catalytic activity rapidly increases with addition of copper to nickel up to 25 wt. % in alloy catalyst. The selectivity to propylene and extent of polymerization increase with the increase of copper in the alloy. Nickel-based catalysts have been used in commercial processes for the selective hydrogenation of acetylenic impurities in mixed steams of olefins and diolefins. [0011] Despite recent improvements made in the performance of catalysts, still further improvement is desired for the selective hydrogenation of acetylenic compounds in a C.sub.2 or C.sub.3 mixed olefin stream to improve selectivity, activity and catalyst cycle time for the production of large volume olefins such as propylene and ethylene. For the commercial production of large volume commodities, such as propylene, even small improvements in selectivity of MAPD to propylene or catalyst activity is highly desirable. SUMMARY OF THE INVENTION [0012] Briefly the present catalyst is a supported catalyst for selective hydrogenation of acetylenes comprising Ni deposited with a promoting amount of Pd on an aluminum oxide support, which contains mixed oxides of MAI.sub.2O.sub.4 with spinel structures, where M is any divalent cation, preferably comprising 3-15 wt. % Ni promoted with 0.005-0.2 Pd on a support. The catalysts are prepared by depositing nickel promoted with palladium on a support, containing one or more optional elements from copper, silver, Group IA (Li, Na, K, Rb, Cs, Fr) and Group IIA (Be, Mg, Ca, Sr, Ba, Ra) and B (Zn, Cd) of the periodic table of elements and characterized as: TABLE-US-00002 Range of component Preferably Component wt. % wt. % Ni 3-15 4-11 Cu 0-1 0.01-0.6 Pd 0.005-0.2 0.01-0.1 Ag 0-10 0-5 Group IA 0-2.5 0-1.5 Group IIA & B 0-25 0.1-5 Where the weight % of the active components are based on the total weight of active components and support. [0013] A promoting amount of Pd means an amount less than 10% of the Ni present. DETAILED DESCRIPTION [0014] The catalysts are useful for hydrogenation reactions such as selective hydrogenation to remove acetylenic impurities in various mixed streams of C.sub.2-C.sub.12 olefins, diolefins and styrene, and hydrogenation of benzene to cyclohexane. Passing a mixture of a hydrocarbon feed stream and hydrogen gas through a catalytic reaction zone or a series of two catalytic reaction zones which carries out hydrogenation reactions such as the selective hydrogenation of acetylenic compounds. A catalytic reaction zone may contain one catalyst or several different catalysts. If the selective hydrogenation is carried out in a series of two catalytic reaction zones, optionally the catalyst in the second reaction zone may contain Cu as a promoter and modifier. The poisoning effects of organic mercaptans and organo-mercuric compounds for the nickel catalysts promoted with Cu in the second catalytic reaction zone are neutralized in the first catalytic reaction zone. A portion of the catalyst in the first catalytic reaction zone is sacrificed as a guard bed for the poisonous impurities. The improvement made for the hydrogenation process in this invention is higher selectivity or higher recovery of the useful materials such as mono-olefins, diolefins, or both, than those processes based on conventional nickel catalysts or conventional palladium-based catalysts. The C.sub.4 acetylenic impurities in a mixed crude butadiene stream can be completely removed by selective hydrogenation with higher recovery of 1,3-butadiene in the present process, than prior art nickel catalysts. Therefore, this invention allows elimination of one of two extractive distillation columns, resulting in simpler and cheaper separation of 1,3-butadiene from the mixed stream. [0015] The catalyst is particularly useful for removing MAPD or acetylene in crude mixed C.sub.2-C.sub.3 olefin streams and phenyl acetylene in crude styrene stream by selective hydrogenation. Methyl acetylene/propadiene (MAPD) is not a compound but covers the unstable compounds methyl acetylene and propadiene which may be depicted as follows: [0016] The improvement is made by depositing Ni promoted with palladium and preferably copper on a support. The catalyst may contain one or more optional elements from Group I and Group II, such as Ag, Ca, Mg, etc. When silver is used as an optional component, silver is deposited on a support in any of following methods; prior-deposition or post-deposition to deposition of nickel, co-deposition with nickel, combinations of two or all of these. The optional components, other than Ag are deposited on alumina prior to deposition of active metal components Ni, Cu, Pd and Ag. Deposition of Ni on a support can be carried out by performing either a single or multiple impregnations in any method. [0017] A preferred catalyst is a supported catalyst for selective hydrogenation of acetylenes selected from the group consisting of 3-15 wt. % Ni, 0.005-0.2 Pd, 0.0-1 wt. % copper, 0.0-10 wt. % Ag, 0-1.5 of at least one member of Group IA and 0.0-25 wt. % of at least one member of Group IIA and IIB deposited on a support, more preferably selected from the group consisting of 4-11 wt. % Ni, 0.01-0.1 Pd, 0.01-0.6 wt. % copper, 0.0-5 wt. % Ag, 0.0-1.5 of at least one member of Group IA and 0.1-5 wt. % of at least one member of Group IIA and IIB deposited on a support. [0018] The preferred support will have BET surface area from about 10 to 100 m 2/g, preferably from about 12 to 75 m 2/g. Examples of such supports are alumina, silica, beta-silicon carbide, carbon, mixed metal oxides, ceramics, various structured materials for column packing, etc. The preferred alumina is prepared by calcining at a temperature from about 1000 to 1250.degree. C. The diameter of a preferred shaped support is from 0.2 mm to 3 mm, preferably from 0.4 to 2.5 mm, most preferably from 0.7 mm to 1.5 mm. The preferred alumina is alpha, theta, delta-alumina or a mixture of these, which have BET surface area, preferably from 10 to about 75 m 2/g. Additional optional elements are any elements from Group 1 and 11 in the Periodic Table. [0019] A preferred support is aluminum oxide, which contains mixed oxides of MAI.sub.2O.sub.4 with spinel structures, where M is any divalent cation, such as Mg, Ca, Zn, Ni, Co, Cu, Mn, etc. Also, up to 30% of aluminum in mixed oxides can be replaced with Ga or In. The content of spinel in aluminum oxide support can be any amount, but preferably from 0.1% to 50%, most preferably from 0.2% to 20%. [0020] When catalyst containing optional elements are prepared with alumina support, one or more elements from Group II is deposited on preferably gamma or eta-alumina and then calcined at from about 900 to 1250.degree. C. to prepare a spinel containing alumina support. One can also prepare other divalent ions such as copper, nickel or copper-nickel spinel containing alumina support in a similar manner. Continue reading... Full patent description for Selective hydrogenation process and catalyst Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Selective hydrogenation process and catalyst patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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