CN-119793527-B - Regeneration method of metal modified mordenite catalyst for methanol amination reaction

CN119793527BCN 119793527 BCN119793527 BCN 119793527BCN-119793527-B

Abstract

The invention discloses a regeneration method of a metal modified mordenite catalyst used in methanol amination reaction, belonging to the technical field of catalyst regeneration. The catalyst regeneration method comprises the steps of firstly removing non-framework aluminum in a catalyst by using an organic acid solution, then washing by using an organic solvent to remove residual organic acid and part of carbon deposit after acid treatment, then oxidizing the carbon deposit on the surface of the catalyst by using a hydrogen peroxide solution and inert mixed gas containing ozone, and finally reducing active metal components in the catalyst by using hydrogen. The regeneration method can effectively remove carbon deposit on the surface of the catalyst at low temperature, reduce the generation of non-framework aluminum on the surface of mordenite in the regeneration process, effectively prolong the service life of the catalyst, and keep good reaction performance of the regenerated catalyst in the amination reaction of methanol.

Inventors

GUO JIANGFENG
FU QI
ZHANG YUPING
WANG YANJIANG
LI TONGJI

Assignees

湖北三峡实验室
湖北兴发化工集团股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241213

Claims (11)

1. A process for regenerating a metal modified mordenite catalyst for use in a methanol amination reaction comprising the steps of: 1) Sequentially soaking the metal modified mordenite catalyst with reduced activity in an organic acid solution, filtering and drying, wherein the organic acid solution is one or more selected from 4-chloro-3-nitrobenzoic acid, p-nitrotoluene phthalic acid, 4-bromophthalic acid and 2,2' -dithiodibenzoic acid; 2) Washing the dried catalyst by adopting an organic solvent, filtering and drying, 3) Filling the dried and cooled catalyst in a fixed bed reactor, firstly, programming the temperature of the reactor to 70-90 ℃ under inert atmosphere, and after the temperature is stable, introducing hydrogen peroxide solution for treatment for 10-16 hours, wherein the concentration of the hydrogen peroxide solution is 5% -20%; 4) Introducing an inert gas purging pipeline, programming the temperature of the reactor to 105-115 ℃, and continuously introducing an inert mixed gas containing ozone for treatment for 6-24 hours after the temperature is stabilized by 2h ℃; 5) And (3) introducing an inert gas purging pipeline, programming the temperature of the reactor to 400-550 ℃, and continuously introducing hydrogen for treatment for 6-20 h after the temperature is stabilized to 0.5-1 h, so as to obtain the regenerated catalyst.
2. The method for regenerating a metal modified mordenite catalyst used in a methanol amination reaction according to claim 1, wherein the metal modified mordenite catalyst is alkaline earth metal and transition metal modified mordenite, the mass of alkaline earth metal element is 20% -60% of that of mordenite, the mass of transition metal element is 1% -5% of that of mordenite, the silicon-aluminum ratio of mordenite is 5% -60, the alkaline earth metal element is one or more selected from barium and calcium, and the transition metal element is one or more selected from nickel, cobalt, copper and zinc.
3. The method for regenerating a metal modified mordenite catalyst used in a methanol amination reaction according to claim 1, wherein the organic acid solution has a pH range of 4 to 6.
4. A method of regenerating a metal modified mordenite catalyst used in a methanol amination reaction according to claim 1 wherein the organic solvent is selected from one or more of ethanol, diethyl ether, chloroform.
5. The method for regenerating a metal-modified mordenite catalyst used in a methanol amination reaction according to claim 1, wherein the temperature rising rate is 1-40 ℃ per minute.
6. The method for regenerating a metal-modified mordenite catalyst used in a methanol amination reaction according to claim 5, wherein the temperature rising rate is 5-8 ℃ per minute.
7. The method for regenerating a metal modified mordenite catalyst used in a methanol amination reaction according to claim 1, wherein the concentration of ozone in the inert atmosphere containing ozone is 3-50%, and the inert atmosphere is one or a combination of more than two of argon, nitrogen and helium.
8. A method for preparing methylamine by catalyzing amination of methanol, which is characterized by comprising the following steps: s1, regenerating a metal modified mordenite catalyst with reduced activity according to the regeneration method of any one of claims 1-7 to obtain a metal modified mordenite catalyst; s2, introducing the mixed liquid of methanol and liquid ammonia into a preheater for vaporization, and then introducing the vaporized mixed liquid into a fixed bed reactor filled with the metal modified mordenite catalyst obtained in the step S1 for reaction to obtain mixed products of different methylamines.
9. The method of claim 8, wherein the vaporization temperature is 200-300 ℃.
10. The method according to claim 8, wherein the reaction temperature is 350-450 ℃ and the reaction pressure is 1-3 MPa.
11. The method of claim 8, wherein the molar ratio of liquid ammonia to methanol is 1.2-2:1.

Description

Regeneration method of metal modified mordenite catalyst for methanol amination reaction Technical Field The invention belongs to the technical field of catalyst regeneration, and particularly relates to a method for regenerating a metal modified mordenite catalyst used in a methanol amination reaction. Background Methylamine is an important fine chemical product and is often used as an intermediate for water treatment agents, pesticides, medicines, surfactants and solvents. The method for preparing methylamine by amination of methanol is a main mode for industrially producing methylamine due to the advantages of easily available raw materials, low price, environment-friendly process and the like. The limitation of thermodynamic equilibrium, the proportion of equilibrium catalysts such as zirconium oxide, tungsten oxide and the like for catalyzing the amination reaction of methanol to generate monomethylamine (MMA), dimethylamine (DMA) and Trimethylamine (TMA) can not meet the market demand, so the Mordenite (MOR), ZSM-5 and the like with shape-selective catalytic function are the research hot spots in recent years. The alcohol amination mechanism generally comprises three sequential steps, 1) dehydrogenation of an alcohol to form an aldehyde/ketone, 2) C-N coupling of the aldehyde/ketone with ammonia to form an imine, and 3) hydrogenation of the imine to form an amine. In the alcohol ammoniation process, the dehydrogenation step is considered to be the block rate step. The alkaline earth metal and transition metal modified mordenite catalyst can improve the reaction performance of methanol amination in terms of modifying pore channel structure, regulating acid property, increasing dehydrogenation active site and the like, but as the reaction time is prolonged, the selectivity of trimethylamine and the conversion rate of methanol are gradually reduced, so that the catalyst deactivation is mainly caused by three aspects of 1) coke generation, namely that organic matters adsorbed on the surface of the catalyst are coked and charred, the pore structure of the catalyst is blocked and the reaction active site is covered, 2) sintering of metal elements, namely that the high temperature and high pressure reaction conditions lead to agglomeration of metal particles, the active site is reduced, and 3) dealumination of a zeolite framework, namely that water vapor generated in the reaction system can gasify part of coke, but leads to dealumination of the zeolite framework and formation of amorphous aluminum species. The method for removing the coke on the surface of the catalyst is commonly used in industry, namely high-temperature oxidation for removing the coke by controlling the oxygen concentration, and the regeneration method is carried out under the condition of high temperature, so that the dealumination of zeolite and the sintering of metal are still aggravated, although the local temperature flying generated by the oxidation of the coke in the regeneration process can be avoided. Therefore, the most ideal regeneration method of the metal modified mordenite catalyst for methanol amination reaction is to combine low-temperature controllable combustion of coke, removal of non-framework aluminum and reduction of transition metal elements. Disclosure of Invention In view of the above, it is an object of the present invention to provide a process for regenerating a metal modified mordenite catalyst for use in a methanol amination reaction. The invention is realized by adopting the following technical scheme: The method for regenerating the metal modified mordenite catalyst used in the methanol amination reaction comprises the steps of firstly removing non-framework aluminum from metal modified mordenite with reduced activity by using an organic acid solution, then washing by using an organic solvent, filtering and drying, filling the dried catalyst into a fixed bed, introducing hydrogen peroxide solution and inert mixed gas containing ozone, oxidizing at low temperature and reducing by using hydrogen, and finally obtaining the regenerated catalyst. A process for regenerating a metal modified mordenite catalyst for use in a methanol amination reaction comprising the steps of: 1) Sequentially soaking the metal modified mordenite catalyst with reduced activity in an organic acid solution, and then filtering and drying; 2) Washing the dried catalyst by adopting an organic solvent, filtering and drying, 3) Filling the dried and cooled catalyst into a fixed bed reactor, firstly, programming the temperature of the reactor to 70-90 ℃ in an inert atmosphere, and after the temperature is stable, introducing hydrogen peroxide solution for treatment for 10-16 hours; 4) Introducing an inert gas purging pipeline, programming the temperature of the reactor to 105-115 ℃, and continuously introducing an inert mixed gas containing ozone for treatment for 6-24 hours after the temperature is stabilized by 2h ℃; 5) And (3) introducing