A kind of ruthenium-based ammonia synthesis catalyst and preparation method thereof

A technology of ammonia synthesis and catalyst, applied in the field of ammonia synthesis, can solve the problems of low catalytic activity, poor hydration resistance, small specific surface area, etc., achieve large specific surface area, prevent hydrogen inhibition, and improve low-temperature and low-pressure activity.

Active Publication Date: 2019-09-03
FUZHOU UNIV ASSET MANAGEMENT CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem solved by the present invention is to overcome the defects of small specific surface area, poor hydration resistance and low catalytic activity of existing ruthenium-based ammonia synthesis catalysts with composite oxides as the carrier, and then provide a catalyst with a large specific surface area, Ruthenium-based ammonia synthesis catalyst with good hydration resistance and high catalytic activity and preparation method thereof

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] The preparation method of the ruthenium-based ammonia synthesis catalyst provided by the present embodiment comprises the following steps:

[0030] (1) Dissolve 20g of urea in 100g of water to form a nitrogen-containing solution, load the nitrogen-containing solution on magnesium-aluminum hydrotalcite with a magnesium-aluminum molar ratio of 0.6, heat and dry at 100°C, and Roasting in a nitrogen atmosphere at 190°C for 2 hours to obtain nitrogen-doped magnesium aluminum hydrotalcite, the doping amount of nitrogen element by mass is 5.5% of the mass of magnesium aluminum hydrotalcite;

[0031] (2) The above-mentioned nitrogen-doped magnesium aluminum hydrotalcite was heated to 630°C at a rate of 15°C / min and kept roasted for 1h, and then heated to 700°C at a rate of 3°C / min and kept roasted for 0.75h, and the roasted product It is the catalyst carrier, which contains 30v% spinel phase;

[0032] (3) Heating potassium fluorotantalate and sulfuric acid to above 400°C, and ...

Embodiment 2

[0036] The preparation method of the ruthenium-based ammonia synthesis catalyst provided by the present embodiment comprises the following steps:

[0037] (1) Dissolve 15ml of ammonia water in 90ml of water to form a nitrogen-containing solution, and load the nitrogen-containing solution on magnesium-aluminum hydrotalcite with a magnesium-aluminum molar ratio of 1.7 by an equal-volume impregnation method, heat and dry at 80°C, and Roasting in an ammonia atmosphere at 200°C for 0.5h to obtain nitrogen-doped magnesium aluminum hydrotalcite, the doping amount of nitrogen element by mass is 8% of the mass of magnesium aluminum hydrotalcite;

[0038] (2) The above-mentioned nitrogen-doped magnesium aluminum hydrotalcite was heated to 600°C at a rate of 10°C / min and kept roasted for 3h, and then heated to 710°C at a rate of 5°C / min and kept roasted for 0.5h, and the roasted product It is the catalyst carrier, which contains 45v% spinel phase, and the pore radius distribution is in t...

Embodiment 3

[0043] The preparation method of the ruthenium-based ammonia synthesis catalyst provided by the present embodiment comprises the following steps:

[0044] (1) 12ml of hydrazine hydrate was dissolved in 100ml of water to form a nitrogenous solution, and the nitrogenous solution was loaded on magnesium-aluminum hydrotalcite with a magnesium-aluminum molar ratio of 2.5 by an equal-volume impregnation method, heated and dried at 90°C, and Roasting in an ammonia atmosphere at 200° C. for 1 h to obtain nitrogen-doped magnesium aluminum hydrotalcite, the doping amount of nitrogen element by mass is 10% of the mass of magnesium aluminum hydrotalcite;

[0045] (2) The above-mentioned nitrogen-doped magnesium aluminum hydrotalcite was heated to 650°C at a rate of 5°C / min and kept roasted for 2h, and then heated to 720°C at a rate of 1°C / min and kept roasted for 0.5h, and the roasted product It is the catalyst carrier, which contains 37v% spinel phase;

[0046] (3) Heating potassium fluor...

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Abstract

The invention provides an ammonia synthesis catalyst and a preparation method thereof. The catalyst uses ruthenium as an active component, samarium and tantalum as additives, and a roasted product of nitrogen-doped magnesium aluminum hydrotalcite as a carrier, and the carrier includes spinel The existence of the phase can improve the hydration resistance of the support, while the remaining composite metal oxide solid solution can ensure that the support still has a large enough specific surface area, a uniform pore structure and a pore radius distributed within the mesopore range, plus The nitrogen element doped in the carrier can not only increase the electron density and basic active sites on the surface of the carrier, but also make the active component ruthenium more firmly loaded on the carrier; and tantalum can activate nitrogen gas decomposition Separation, samarium can play a role in inhibiting hydrogen poisoning, and the combination of the above components is beneficial to the synthesis of ammonia, thereby improving the low-temperature and low-pressure activity of the catalyst.

Description

technical field [0001] The invention belongs to the technical field of ammonia synthesis, and in particular relates to a ruthenium-based ammonia synthesis catalyst and a preparation method thereof. Background technique [0002] Ammonia is one of the important inorganic chemical products. Since the German chemist Haber discovered in 1902 that nitrogen and hydrogen can be directly combined into ammonia under high temperature and high pressure in the presence of catalysts, ammonia synthesis catalysts have become a key technology and research focus in the field of ammonia synthesis. [0003] Compared with traditional molten iron ammonia synthesis catalysts, ruthenium-based ammonia synthesis catalysts are known as the second generation of ammonia synthesis catalysts after molten iron catalysts due to their characteristics of low temperature, low pressure and high activity. The ruthenium-based ammonia synthesis catalyst is mainly composed of active metal ruthenium, carrier and aux...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/24B01J35/10C01C1/04
CPCC01C1/0411B01J27/24B01J35/638B01J35/635B01J35/647B01J35/615Y02P20/52
Inventor 江莉龙林建新倪军林炳裕林科
Owner FUZHOU UNIV ASSET MANAGEMENT CO LTD
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