SU1202609A1 - Method of preparing nickel-chromium catalyst - Google Patents

Description

This invention relates to a method for preparing a nickel chromium catalyst.

The aim of the invention is to simplify and create a drainless process due to the fact that drying and calcination is carried out by spraying a mixture of solutions of nickel nitrate and ammonium dichromate on a heated nozzle of inert material in a fluidized bed mode at 710-740 0 and closed circulation heat carrier - inert gas through a fluidized bed ..

An example. Prepare a mixture of solutions of nickel compounds and chromate based on proportion: as of 1 May. waters take 5 May, h, nickel nitrate and 1 mah. ammonium bichromate. At the specified ratio of raw materials, a catalyst of composition is obtained, wt%: N.063; 27.

An inert coolant, such as nitrogen, is heated in an electric heater to 120 ° C and is fed to the spraying of the mixture of solutions in a fountain kiln. In the gushing furnace, in a fluidized bed, there is an aluminum chip with a particle size of 2-3 mm. To maintain the particles in a fluidized state, an inert gaseous coolant — nitrogen, preheated to 330 ° C in an electric heater — is also supplied to the bottom.

The nitrogen velocity at the beginning of boiling is 0.22 m / s, the actual nitrogen velocity is 0.66 m / s, the number of fluidization is 3, the porosity of the bed is 0.5, the temperature in the bed. The consumption of nitrogen for spraying 1 l of a solution of 6.65.

In the spouting furnace, drops of the solution fall on the aluminum crumb. Water evaporates instantly. At the same time, thermal decomposition and chemical interaction of nickel nitrate and ammonium dichromate occur with the formation of a catalytically active composition with a developed surface.

The whole process of formation of the catalytic mass takes a few seconds. Due to the low continuity of the process, the nickel crystals do not have time to be enlarged, the nickel is in a fine state 2026092

Research institutes, and the catalyst as a result of this becomes more active. A recommended process temperature of 310-340 ° C is justified by the fact that

5 at a lower temperature not

the complete decomposition of nickel and chromium salts is achieved, and at a higher temperature, sintering of the pores, the capillary, is carried out;

 About nickel crystals, the reduction of the active surface and, as a consequence, a decrease in catalyst activity.

The boiling regime depends on the material, the particle size of the fluidized bed and the nature of the heat carrier.

The particles of the formed catalyst are carried away by the flow of heat-transfer agent to the dust collectors, where they are separated from the gas and then mixed with graphite. The resulting mass is reduced and molded by known methods.

Gas - coolant is passed

25 through the heat exchanger - condenser and after purification of nitrogen oxides in the apparatus with a gas blower, it is again fed through an electric heater to the fountain kiln. In this way,

30 gas - coolant makes a closed circulation in the system without vosbosov in the atmosphere.

Example 2. A mixture of solutions of nickel and chromium compounds is prepared as in Example I.

An inert coolant, for example, nitrogen, is heated in an electric heater up to 130 ° C and is fed to the spraying of the mixture of solutions in a fountain kiln. In a flowing furnace in the fluidized bed state there are balls of quartz with a size of 2 mm. To keep the balls in a fluidized state, an inert gaseous coolant, nitrogen, preheated before in an electric heater, is supplied to the bottom 2 of the furnace. Nitrogen velocity at the beginning of boiling 0.24 m / s

JQ is the actual nitrogen velocity of 0.65 m / s, fluidization of 3, the porosity of the layer is 0.5, the temperature in the layer is 330 C. The consumption of nitrogen for spraying 1 liter of solution 6.65.

55 in the gushing furnace drops of solution fall on quartz beads. Water evaporates instantly. Thermal decomposition occurs simultaneously.

and chemical interaction of nickel nitrate and ammonium bichromate with the formation of a catalytically active composition with a developed surface. The remaining operations are carried out in Example 1,

Example 3 A mixture of solutions of nickel and chromium compounds is prepared as in Example 1. An inert heat carrier, such as nitrogen, is heated in an electric heater to 130 ° C and fed to the spraying of the mixture of solutions in a flowing kiln. In the gushing furnace, corundum particles 1.5 mm in size are in the fluidized bed state. To maintain the particles in a fluidized state, an inert gaseous coolant, nitrogen, preheated to 340 ° C in an electric heater, is supplied to the lower part of the furnace. The nitrogen velocity at the beginning of boiling is 0.24 m / s, the actual nitrogen velocity is 0.48 m / s, the number of fluidization is 2, the porosity of the bed is 0.5, the temperature in the bed is 330 ° C. The consumption of nitrogen for spraying 1 l of a solution of 6.65 nm / h.

In the gushing furnace, droplets of the solution fall on corundum particles. Water evaporates instantaneously, thermal decomposition and chemical interactions occur simultaneously. Catalyst Quality Indicator

The specific active (nickel) surface

Catalytic activity, measured by the rate of benzene hydrogenation at 100 ° C and at,. ben angry

gk-r.h

Crushing strength, kg / cm

VNIIPI Order 8347/6 540 Subsidiary Branch of the PPP Patent, Uzhgorod, Projecto st., 4

Nickel nitrate with ammonium biochromate to form a catalytically active composition with a developed surface. The remaining operations are carried out according to Example 1. The table shows the indicators of the quality of the catalysts obtained by the proposed and known methods.

From the above data it can be seen that the proposed method provides a high quality catalyst.

The proposed method is simplified compared to a known method by eliminating the steps of precipitation, filtering, washing the precipitate and drying and calcining the catalyst mass in one stage, for a short time, at high speed.

In the method of preparation of the catalyst according to Example 2, there are no discharges of harmful substances into the water bodies and the atmosphere: the coolant makes a closed circulation, the evaporated water is condensed from the heat transfer gas and again used to prepare initial solutions of nickel and chromium salts. Due to this, there are no emissions of gases into the atmosphere and discharge of polluted waters into water bodies.

On the proposed method.

By a known method

25.0

5-5,5

30-46

Claims (1)

(54) METHOD FOR PREPARING A NICKEL CHROME CATALYST FOR benzene hydrogenation, including mixing solutions of nickel nitrate and ammonium dichromate, drying, calcining, reducing and shaping the catalyst mass, characterized in that, in order to simplify the process and create a drainless process, drying and calcining carried out by spraying a mixture of solutions on a heated nozzle of an inert material with a coolant - inert gas in g fluidized bed mode at 310-340 ° C and closed circulation of the coolant - inert gas through boiling layer.