RU2064840C1 - Method of catalyst preparation - Google Patents

Abstract

FIELD: chemistry, petrochemical industry, oil refinery; hydrogen-bearing gasses purification in presence of catalysts in particular. SUBSTANCE: powder of active oxide of aluminum with 0.1 - 0.3 mass % of sodium oxide, is mixed with salts of nickel, molybdenum and nitric acid. Nitric acid is introduced two times with ratio of portions from 2.64 : 1 to 10.8 : 1. Catalyst has following shares of components: nickel oxide 1.5 - 2.5, molybdenum oxide 5.0 - 8.0, aluminum oxide - balance. EFFECT: improved qualities of catalysts. 2 tbl

Description

 The present invention relates to the field of purification of hydrogen-containing gases from sulfur, in particular, hydrotreatment of raw materials for the production of hydrogen by steam conversion of refinery gases. Fluctuations in refinery gases make specific demands on the hydrotreatment catalyst.

The closest in technical essence and the achieved result to the proposed technical solution is an aluminum-nickel-molybdenum catalyst containing 4.5% wt. NiO and 17.8% by weight of MoO ₃ [2] The method of its preparation consists in mixing alumina powder with nickel and molybdenum salts with the addition of nitric acid, followed by molding, drying and calcination.

The disadvantages of this catalyst and the method of its preparation are:
high content of active components (4-5% and 17-19-19 wt.% oxides of Nickel and molybdenum, respectively);
low efficiency, expressed in an uncontrolled increase in temperature in the catalyst bed when it is used in the process of hydrotreating a refinery gas with a methane equivalent of M = 0.15;
The disadvantage of the method of preparation of the catalyst [2] is the restriction on the use as a carrier of active alumina with a sodium oxide content of not more than 0.1 mass;
The aim of the proposed technical solution is to increase the efficiency of the catalyst by eliminating an uncontrolled increase in temperature in the catalyst bed, reducing the content of active components in the catalyst, expanding the raw material base of the carrier.

This goal is achieved by the fact that in the method of preparing the catalyst by mixing the powder of active alumina containing sodium oxide with nickel nitrate, nitric acid and ammonium molybdenum acid, nitric acid is introduced in two doses, namely, after the introduction of nickel nitrate and after the introduction of ammonium molybdenum at the ratio of the first and second servings from 2.64: 1 to 10.8: 1, the active alumina contains 0.1% 0.30% wt. sodium oxide, and salts of the active components are introduced in an amount providing a content of 5-8% wt. in the catalyst. MoO ₃ and 1.5-2.5 wt. NiO.

Comparative analysis with the prototype shows that the claimed technical solution differs from the prototype in that the catalyst contains 5-8 wt. MoO ₃ and 1.5-2.5 masses of NiO against 17.8% wt. MoO ₃ and 4.5% wt. NiO, and the method for its preparation includes the introduction of nitric acid in two doses instead of one and the use of aluminum oxide with a sodium oxide content of 0.1-0.30% by weight. instead of 0.10% wt.

 In the study of other well-known technical solutions in the art, signs that distinguish the claimed invention from the prototype were not identified. Thus, they provide the claimed technical solution according to the criteria of "novelty" and "significant differences".

 Examples of the implementation of the proposed technical solution.

 EXAMPLE 1

 358.8 g of active alumina powder with a content of 0.22% sodium oxide (98% by weight of the powder has a size of less than 50 μm) was loaded into the working bath of the kneading machine, 38.4 g of nickel hexahydrate was added, mixed for 15 minutes. 108 ml of 10% nitric acid were added, mixed for 15 minutes, 38.0 g of ammonium molybdenum acid were added to the mixture, stirred for 25 minutes, 10 ml of 10% nitric acid was added and mixed for 15 minutes until a homogeneous mass was obtained.

 The catalyst mass was formed by extrusion through a die with a diameter of 3.2 mm.

The extrudates were air-dried, dried at a temperature of 120 ^{° C.} for 2 hours, calcined at a temperature of 550 ^{° C.} for 8 hours.

The composition of the catalyst:
7.9% wt. MoO ₃
2.1% wt. Nio
0.21% wt. Na ₂ O
The rest is Al ₂ O ₃ .

 Evaluation of the effectiveness of the catalyst in the process of hydrotreatment of raw materials for the production of hydrogen was carried out as follows.

Since the uncontrolled increase in temperature in the catalyst bed during the hydrotreatment of raw materials for hydrogen production is associated with exothermic hydrocracking processes, the quantity used as an indicator of the effectiveness of the catalyst
ΔT increase in the temperature of the onset of hydrocracking of model raw materials in comparison with that for the catalyst of the prototype.

 A mixture of n-hexane with hydrogen in a molar ratio of 1: 6, which corresponds to a refinery gas with a methane equivalent of M = 0.15, was used as model raw material.

 The process was carried out in a microflow installation according to OST 38.01130, p.p. 12.1-12.2 a.b.

 The beginning of the hydrocracking process was fixed chromatographically by the appearance of peaks in the chromatograms corresponding to the yield of methane and ethane.

ΔT = T ₂ -T ₁ ,
Where
T _{1 the} temperature of the onset of hydrocracking of n-hexane on the prototype catalyst;
T _{2 the} temperature of the onset of hydrocracking of n-hexane on the catalyst according to the proposed technical solution.

T ₁ = 450 ^o C.

The criterion of catalyst efficiency is ΔT = 10 ^° C.

For the catalyst according to example 1
T ₂ = 465 ^o C, hence ΔT = 15 ^° C.

 The strength of the catalyst, determined by cracking the granules with a knife, is 1.20 kg / mm in diameter.

 In the table. 1 and 2 are also other examples of implementation (2-4) of the proposed technical solution, as well as a comparative prototype catalyst GO-30-7.

 As can be seen from the embodiments of the catalyst and the method of its preparation, the proposed catalyst contains active components in an amount of 2.5-3.5 times less than in the prototype catalyst.

The effectiveness of the catalyst for the selected parameter of temperature reduction during the hydrocracking of n-hexane exceeds the criterion value by 5-31 ^o C, and relative to the prototype catalyst is 15-41 ^o C.

 At the same time, the raw material base of the carrier was expanded by the content of sodium oxide impurities in it up to 0.3% wt. against 0.1% in the prototype method.

Claims (1)

 A method of preparing a catalyst, comprising mixing an active alumina powder containing sodium oxide with nickel nitrate, introducing nitric acid into the mixture and then mixing it with ammonium molybdenum acid, forming, drying and calcining the catalyst, characterized in that nitric acid is introduced in two steps, this second portion is administered after the introduction of ammonium molybdenum in the ratio of the first and second portions of 2.64 10.8 1, and the active alumina contains 0.1 to 0.3 wt. sodium oxide, and the resulting catalyst contains, by weight. Nickel oxide 1.5 2.5
Molybdenum oxide 5.0 8.0
Alumina Else

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