SU1204252A1 - Method of preparing nickel catalyst for conversion of natural gas with steam - Google Patents

Description

The invention relates to methods for the preparation of nickel catalysts for the conversion of natural gas with steam and can be used in the processes for producing hydrogen containing process gas.

The aim of the invention is to obtain a catalyst with increased resistance to overgrazing due to the introduction of an additional step.

 PRI me R 1 (comparative).

The catalyst is prepared according to a known method.

96 kg of ground alumina, 12.6 kg of calcium nitrate, 6.3 kg of magnesium nitrate and 30 kg of petroleum coke (fraction less than 0.5 mm) are thoroughly mixed. 30% nitric acid is poured into the mixture with continuous stirring until homogeneous elastic mass.At 130 weight.h. dry weight (including petroleum coke) requires 30-37 parts by weight. 30% nitric acid.

Pellets of the carrier are formed from the mass on the screw press, which is carried out for 10–12 h, dried at 100–120 ° C, and calcined at 1400 ° C. The prepared carrier is impregnated three times with a solution of nickel and aluminum nitrate salts for 20 min. 122 kg Ni (N0,) 6 and 46 kg A1 (N0j) 3 9 HjO) with calcination after each impregnation at 380-400 s for the decomposition of nitrates. Then the catalyst is reduced in a stream of hydrogen at. The catalyst has the following composition, may.% Nickel oxide 10; calcium oxide 3, magnesium oxide 1; alumina rest.

EXAMPLE 2 The catalyst is prepared as in Example 1 and after reduction with hydrogen at 400-700 ° C, it is further calcined in a stream of hydrogen at 700 G for 4 hours. The composition of the catalyst is the same as in Example 1.

Froze The catalyst is prepared analogously to example 1, after reduction, further calcined in a stream of hydrogen at 3 hours.

EXAMPLE 4 The catalyst is prepared analogously to example 1 and is further calcined at 900 ° C for 2 hours.

2042522

EXAMPLE 5 The catalyst is prepared analogously to example 1 and is further calcined at 1000 ° C 1h.

5 Approx. The test of the activity of the catalysts is carried out on a weight kinetic installation, which allows continuous control of the carbonization rate of the catalyst 10 during the reaction. Carbonic acid gas was used as an oxidizing agent; methane or natural gas was used as a coking agent.

15 A portion of the catalyst (0.2 g) is placed in a quartz basket in the flow reactor of the weighing unit, heated to 700 ° C in a stream of hydrogen. After reaching constant weight

20, the temperature is reduced to 500 ° C and natural gas is fed into the reactor. In a stream of natural gas (flow rate of 0.1 l / min) the catalyst is kept for 30 minutes. At the same time, it progresses to the corner.

25 catalyst life, speed W | which is controlled by weight change. Then the sms of natural and carbon dioxide is fed into the reactor.

in the ratio of 1: 4 and increase the temperature to 600 C, In the current of this mixture

the catalyst is kept for 30 minutes, and the speed Wj of its carbonization with the mixture is controlled by the change in weight. The value of about characterizes the tendency of the catalyst to

carbonized. With increasing oi, the propensity for carbonization increases. Since the activity of the nickel high-temperature catalyst in the hydrocarbon conversion reaction in the kinetic region is proportional to the nickel surface, the activity of the catalysts is estimated by the rate of coal deposition in the methane decomposition reaction, which is strictly proportional to the nickel contact surface.

The table presents the results of the effect of calcination in a hydrogen medium on the catalyst activity at

temperature 500 С, general speed 1000 СН.

With an increase in the temperature of the treatment of catalysts in a hydrogen medium, the activity of the fresh catalyst decreases slightly.

After 5 h of the activity of the proposed and well-known catalyz

The ditch becomes the same, and the activity of the known decreases more strongly than the activity of the proposed one. This is explained by the fact that pretreatment with hydrogen stabilizes the structure with kata. Known not heated by 1.25. Proposal - 700 4 1.28

800

900 1000

2 1

1204252..

lysator. A slight decrease in catalyst activity is accompanied by a substantial decrease in the catalyst's tendency; K is carbonized, which is of great importance for the performance properties of the catalyst.

Coaling activity

, g

pure methane, min

III

0.015 0.015

0.013 0.013

1.04

0.015 0.014

0.013

0,860,014 0,0140,013

0,390,013 0,0140,013

Claims (1)

METHOD FOR PREPARING A NICKEL CATALYST FOR CONVERSION OF NATURAL GAS WITH WATER VAPOR by molding granules of an alumina-based support followed by drying and calcining of the carrier by repeatedly impregnating the support with nickel and aluminum nitrates and calcining after each impregnation and reduction with hydrogen, with the aim of producing a catalyst with increased resistance to carbonization, the catalyst after reduction is additionally calcined in a stream _of hydrogen at 800-1000 C for