Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Halogen or compound containing same
Reexamination Certificate
2002-04-26
2004-08-24
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Halogen or compound containing same
C502S227000, C502S229000, C502S302000, C502S334000, C502S339000, C502S349000
Reexamination Certificate
active
06780814
ABSTRACT:
The present invention relates to a multimetallic hydrocarbons conversion catalyst which has the dual-functions of acidity and hydrogenation-dehydrogenation, and the preparation process thereof. In particular, the present invention relates to a multimetallic reforming catalyst comprising platinum and tin and the preparation process thereof.
Catalytic reforming is one of the most important technologies in the petroleum processing, and the main object thereof is to produce gasoline with high octane number, aromatics with wide applications, and hydrogen with low price. At present, the reforming catalysts widely used in industry are mostly bimetallic reforming catalysts such as Pt—Re, Pt—Sn catalysts. It is shown by research that, compared with Pt—Re catalysts, Pt—Sn catalysts have better low pressure stability, and higher aromatics selectivity, have no necessity to be pre-sulfurized, and are more appropriate for moving bed reforming process. The acidity function in the bimetallic catalysts for isomerization is generally provided by porous acidic oxide supports such as alumina and halogens, and the hydrogenation-dehydrogenation function is generally provided by Group VIII metal components such as platinum or palladium. The incorporation of the second metal component, Re or Sn, can greatly improve the stability of the catalyst and reduce the content of the noble metal, platinum.
Several competing reactions take place during the catalytic reforming procedure. These reactions include dehydrogenation of cyclohexanes to aromatics, dehydroisomerization of alkylcyclopentanes to aromatics, dehydrocyclization of acyclic hydrocarbons to aromatics, hydrocracking of paraffins to lighter hydrocarbons less than C
5
, dealkylation of alkylbenzenes, and isomerization of paraffins. In these reactions, the yield of gasoline would decrease due to the formation of light paraffin gases from hydrocracking; the coking reaction would increase the deactivation rate of the catalyst; and the frequent regeneration of the catalyst would increase the operating cost. Therefore, it is always the object of persons skilled in the art to develop a reforming catalyst and process with high selectivity and low carbon deposit rate, wherein the addition of the third or the forth metal component into the bimetallic catalyst is one of the widely used modifying means in the art.
U.S. Pat. No. 3,915,845 discloses a multimetallic catalyst composition for hydrocarbon conversion, comprising 0.01-2.0 wt % of a Pt Group metal, 0.01-5.0 wt % of Germanium, 0.1-3.5 wt % of a halogen and a lanthanide compound, wherein the atomic ratio of lanthanide element/Platinum Group metal is 0.1-1.25. In the catalyst, the Pt Group metal is present as elemental metal state, while the other metals are present as oxide state. The lanthanide elements used are lanthanum, cerium or neodymium.
U.S. Pat. No. 4,039,477 discloses a hydrotreatment catalyst modified with lanthanide metals and the use thereof. Said catalyst comprises a refractory metal oxide, a Pt Group metal, Sn and at least one metal selected from the group consisting of Y, Th, U, Pr, Ce, La, Nd, Sm, Dy and Gd. This patent improves the activity stability of the catalyst by incorporating lanthanide metals into the catalyst and improves the selectivity of the lanthanide-containing catalyst by suppression of the cracking activity due to the presence of tin. In a specific embodiment, the C
5
+
yield in the conversion of hexanes on a Pt—Sn—Ce containing catalyst with a Ce/Pt weight ratio of 0.37 is greater than that of a Pt—Sn containing catalyst.
U.S. Pat. No. 6,059,960 discloses a Pt—Sn multimetallic reforming catalyst containing lanthanide series, wherein the incorporated lanthanide components are Eu, Yb, Sm, or a mixture of Eu and Yb, and more than 50% of the lanthanide metals in the catalyst is a present as EuO. When the composition of the catalyst is Pt—Sn—Eu, the relative activity and selectivity are better when the atomic ratio of Eu/Pt is between 1.3 and 2.0. The selectivity of the catalyst will be lowered when said ratio is less than 1.3. The activity of the catalyst will be greatly lowered when the atomic ratio of Eu/Pt is higher than 2.0.
It is an object of the present invention to provide a lanthanide-modified Pt—Sn reforming catalyst with high activity, high selectivity and good activity stability.
It is another object of the present invention to provide a process for preparing the catalyst described above.
The inventors have found that the bimetallic reforming catalyst modified by cerium and europium can improve the selectivity and anti-carbon depositing ability of the catalyst, and thereby increase the liquid yield of the reforming reaction and prolong the lifetime of the catalyst. In particular, the multimetallic catalyst according to the present invention comprises the following components on the basis of mass percents:
Group VIII metal
0.01-2.0
Group IVA metal
0.01-5.0
Eu
0.01-10.0
Ce
0.01-10.0
Halogen
0.10-10.0
Refractory inorganic oxide
63.00-99.86.
Said Group VIII metal is selected from the group consisting of Pt, Pd, to Ru, Rb, Ir, Os or the mixtures thereof, with Pt being preferred. The Group VIII metal component is the major active component of the catalyst according to the present invention. The state of the Pt Group metal present in the catalyst may be an elemental metal or a compound, such as the oxide, sulfide, halide, or oxyhalide, etc., or a chemical combination with one or more other components in the catalyst. The preferred content of the Group VIII metal in the catalyst is 0.05-1.0 mass % on the basis of the elemental metal.
The Group IVA metal in the catalyst is preferably Ge or Sn, more preferably Sn. This metal component may be present as an elemental metal, or as a compound, such as the oxide, sulfide, halide, or oxyhalide, etc., or as a physical or chemical combination with other components of the support and the catalyst. The Group IVA metals preferably are present as an oxide state in the catalyst product. On the basis of elemental metal, the preferred content of the Group IVA metals in the catalyst according to the present invention is 0.1-2.0 mass %.
The lanthanide metals contained in the catalyst according to the present invention are a mixture of Ce and Eu. In the catalyst, Ce and Eu may be present as a compound, such as an oxide, hydroxide, halide, oxyhalide, or aluminate, or as a chemical combination with one or more other components in the catalyst. Each content of Ce and Eu in the catalyst preferably is 0.05-2.0 mass % on the basis of elemental metal, and more preferably 0.1-1.0 mass %. The atomic ratio of Eu/Pt in the catalyst according to the present invention is 0.2-3.0:1, preferably 0.2-1.0:1, more preferably 0.5-1.0:1, and the atomic ratio of Ce/Pt is 0.2-5.0:1, preferably 0.5-3.0:1. More than 60% of Ce in the reduced catalyst is present as the +3 valence.
The component used for adjusting the acid amount in the catalyst according to the present invention is a halogen, preferably chlorine. The content of the halogen in the catalyst is preferably 0.2-4.0 mass %.
Said catalyst support, which is generally a porous adsorptive material and has a specific surface area of 30-500 m
2
/g, is selected from refractory inorganic oxides. The porous support should have uniform composition 15 and is refractory under the operating conditions. The term “uniform composition” used herein means that the support is not layered and has no concentration gradient of the intrinsic components. If the support is a mixture of two or more refractory materials, these materials have a relative constant content or a uniform distribution throughout the whole support. The refractory inorganic oxides described in the present invention include:
(1) Refractory inorganic oxides, such as alumina, magnesia, chromia, boron oxide, titania, thoria, zinc oxide, zirconia, or the mixtures of the following two oxides: silica-alumina, silica-magnesia, chromia-alumina, alumina-boron oxide, silica-zirconia;
(2) Various ceramics, various alumine, and various bauxites;
Ma Aizeng
Pan Jincheng
Yang Sennian
China Petroleum & Chemical Corporation
Greenblum & Bernstein P.L.C.
Hailey Patricia L.
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