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Process for preparing aniline compounds through hydrogenation of nitrobenzene compounds in multistage fluidized bed

A technology of aniline compounds and nitrobenzenes, which is applied in the chemical industry, can solve the problems of large fluctuations in production tasks, gas velocity fluctuations, space velocity fluctuations of catalysts, narrow gas velocity ranges, complex structures, etc., and achieve multi-stage fluidized bed structure reduction , the proportion of qualified products increased, and the effect of reducing the difficulty of control operations

Inactive Publication Date: 2017-08-25
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this technology uses a catalyst with a relatively uniform particle size, and multi-stage fluidized bed operation relies on higher gas velocities
This leads to not only a very complex structure of this type of fluidized bed, but also a narrow range of applicable gas velocity
It cannot well adapt to the needs of large fluctuations in production tasks in production (often resulting in large fluctuations in gas velocity and catalyst space velocity)
Also prevents devices designed for large scale from effectively operating at low loads

Method used

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  • Process for preparing aniline compounds through hydrogenation of nitrobenzene compounds in multistage fluidized bed
  • Process for preparing aniline compounds through hydrogenation of nitrobenzene compounds in multistage fluidized bed
  • Process for preparing aniline compounds through hydrogenation of nitrobenzene compounds in multistage fluidized bed

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The gas inlet 2, the gas outlet 6, the component system 4, the heat exchange system 3, the transverse porous distribution plate 5, the overflow pipe 7, etc. figure 1 A fluidized bed 1 consisting of two stages.

[0024] Fill the two-stage fluidized bed with double-sieve catalyst (nickel / silicon oxide, particle size distribution of 10-400 microns, double-sieve distribution with 60 microns, 200 microns as the peak center, and 60 microns as the peak center group The mass fraction in the catalyst is 10%), the catalyst and the multi-stage fluidized bed are heated to 180°C with high-temperature gas (air), and the oxygen content in the outlet gas of the fluidized bed is less than 0.5%. The catalyst was reduced at 180° C. for 10 hours at a gas velocity of 0.03 m / s by feeding a mixture of hydrogen and nitrogen (the volume content of hydrogen was 10%). Heat hydrogen together with nitrobenzene to 190°C, pass it into the fluidized bed, and control the catalyst space velocity to 0....

Embodiment 2

[0027] The gas inlet 2, the gas outlet 6, the component system 4, the heat exchange system 3, the transverse porous distribution plate 5, the overflow pipe 7, etc. figure 2 A fluidized bed 1 consisting of three stages.

[0028] Fill the three-stage fluidized bed with a double-sieve catalyst (copper-nickel / silica gel, particle size distribution of 10-350 microns, double-sieve distribution with 70 microns, 250 microns as the peak center, and a group with 70 microns as the peak center The mass fraction in the catalyst as a whole is 30%), the catalyst and the multi-stage fluidized bed are heated to 180° C. with high-temperature gas (nitrogen), and the oxygen in the outlet gas of the fluidized bed is purged by an inert gas (nitrogen). The content is less than 0.5%. The catalyst was reduced at 180° C. for 24 hours by feeding a mixture of hydrogen and nitrogen (the volume content of hydrogen was 10%), and the gas velocity was 0.05 m / s. Heat hydrogen together with methylnitrobenzen...

Embodiment 3

[0031] The gas inlet 2, the gas outlet 6, the component system 4, the heat exchange system 3, the transverse porous distribution plate 5, the overflow pipe 7, etc. image 3 A fluidized bed 1 consisting of four stages.

[0032]Fill the four-stage fluidized bed with double-sieve catalysts (gold-copper / alumina, particle size distribution of 15-450 microns, double-sieve distribution with 80 microns, 300 microns as the peak center, and 80 microns as the peak center The mass fraction of the component in the catalyst is 40%), the catalyst and the multi-stage fluidized bed are heated to 195 °C with high-temperature gas (air), and the fluidized bed outlet gas is purged by an inert gas (nitrogen or argon). The oxygen content is less than 0.5%. The catalyst was reduced at 200° C. for 12 hours by feeding a mixture of hydrogen and nitrogen (the volume content of hydrogen was 20%), and the gas velocity was 0.03 m / s. Heat hydrogen together with chloronitrobenzene to 200°C, pass it into the...

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Abstract

The invention discloses a process for preparing aniline compounds through hydrogenation of nitrobenzene compounds in a multistage fluidized bed. The used catalyst has a double screening characteristic (respectively taking 60-80 microns and 200-300 microns as peak centers), size grading is performed under the gas velocity action, a coarse particle catalyst stacked bed is formed on the lower section of the multistage fluidized bed, and a fine particle catalyst bed is formed on the upper section of the multistage fluidized bed. Moreover, due to the arrangement of an overflow pipe, each catalyst bed section is kept highly stable. Due to an independent heat exchange system, the temperature of each section is kept controllable. The initial fast reaction and strong head transfer function can be realized, and the aim of later advanced gas conversion is achieved. The process disclosed by the invention has the advantages of simplicity in control, high operating flexibility, wide adaptive gas velocity range, high raw material conversion rate (more than 99.990%), high product selectivity (more than 99.40%) and the like.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a process for preparing aniline compounds by hydrogenating nitrobenzene compounds in a multi-stage fluidized bed. Background technique [0002] Aniline is a very important class of chemical products. With the wide application of polyurethane in the fields of construction, automobiles, electrical appliances and packaging materials, the output of methyl diisocyanate (MDI for short, prepared from aniline), the main raw material of polyurethane, has increased rapidly, resulting in a substantial increase in the consumption of aniline. . In addition, methylaniline is the main raw material for preparing another type of isocyanate TDI. Diaminobenzene and chloroaniline are important raw materials for pesticides, organic pigments, pharmaceuticals, and rubber antioxidants. The annual demand for these important chemicals is about 5 million tons. [0003] And the common industri...

Claims

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Application Information

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IPC IPC(8): C07C209/36C07C211/46C07C213/02C07C215/76C07C211/52C07C211/47C07C211/56B01J8/26
CPCC07C209/36B01J8/26C07C209/365C07C213/02C07C211/46C07C215/76C07C211/52C07C211/47C07C211/56
Inventor 骞伟中魏飞
Owner TSINGHUA UNIV
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