CN-122006801-A - Regeneration method of carbon deposition molecular sieve catalyst

Abstract

The invention discloses a regeneration method of a carbon deposition molecular sieve catalyst, belonging to the field of catalyst regeneration. The invention uses low-pressure plasma to ash the carbon deposition molecular sieve catalyst at low temperature, so that the carbon deposition on the molecular sieve is oxidized and decomposed below 200 o ℃. The low pressure plasma ash regeneration process is performed at low temperatures, much lower than conventional calcination (typically 600 o C) regeneration processes. The method effectively prevents the problem of local high temperature on the surface of the molecular sieve caused by carbon deposition combustion heat release in the traditional high-temperature calcination process, and further suppresses the collapse and structure change of the molecular sieve framework. At the same time, the interaction of the low-pressure plasma and the molecular sieve surface helps to inhibit the generation of carbon deposition. According to the invention, lignite pyrolysis is used for preparing aromatic hydrocarbon as a probe reaction, and the performance evaluation of the catalyst obtained by adopting the traditional calcination regeneration and the low-pressure plasma ashing regeneration is compared, so that the results prove that the performance of the low-pressure plasma ashing regenerated catalyst is higher than that of the traditional calcination regenerated catalyst.

Inventors

• WU XUEMEI
• CAO JINGPEI
• YAN CHUANYONG
• SHI WENJU

Assignees

• 徐州工业职业技术学院

Dates

Publication Date

20260512

Application Date

20260410

Claims (5)

1. 1. The regeneration method of the carbon deposition molecular sieve catalyst is characterized by comprising the following steps of: s1, collecting a carbon deposition molecular sieve catalyst after the reaction of preparing aromatic hydrocarbon by lignite catalytic pyrolysis, and grinding the carbon deposition molecular sieve catalyst to obtain carbon deposition molecular sieve catalyst powder; S2, placing the carbon deposition molecular sieve catalyst powder prepared in the step S1 into a low-pressure plasma generator for ashing regeneration treatment, wherein the treatment temperature is 200 o ℃ at the highest, and the atmosphere is O 2 ; And S3, taking the mass change of the catalyst as a basis for whether the regeneration process is finished or not, and judging that the low-pressure plasma ashing regeneration process is finished when the weight difference of the carbon deposition molecular sieve catalyst measured twice is less than 1% of the mass of the carbon deposition molecular sieve catalyst collected in the step S1.
2. 2. The method for regenerating a carbon deposit molecular sieve catalyst according to claim 1, wherein in step S1, the carbon deposit molecular sieve catalyst is a carbon deposit silicoalumino molecular sieve.
3. 3. The method for regenerating a carbon deposition molecular sieve catalyst according to claim 1, wherein in the step S1, the carbon deposition molecular sieve catalyst is a carbon deposition ZSM-5 molecular sieve catalyst, a carbon deposition H-Y molecular sieve catalyst or a carbon deposition MCM-11 molecular sieve catalyst.
4. 4. The method for regenerating a carbon deposit molecular sieve catalyst according to claim 1, wherein in step S1, the carbon deposit molecular sieve catalyst is ground to a particle size of less than 75 μm.
5. 5. The method for regenerating a carbon molecular sieve catalyst according to claim 1, wherein in the step S2, the frequency of the low-pressure plasma generator is 40KHz, and the flow rate of O 2 is 13mL/min.

Description

Regeneration method of carbon deposition molecular sieve catalyst Technical Field The invention relates to the field of catalyst regeneration, in particular to a regeneration method of a carbon deposition molecular sieve catalyst. Background The brown coal in China has rich reserves, but has the characteristics of high moisture, high ash content, high oxygen content and low heat value, and the direct combustion or gasification has low efficiency and serious pollution. Pyrolysis is an effective way for clean and efficient utilization of lignite, and semicoke, gas, tar and other products can be obtained, but the tar products produced by the traditional coal pyrolysis process are complex, the selectivity of light aromatic hydrocarbon is low, and heavy tar is easy to cause equipment blockage. Therefore, the pyrolysis volatile matters are subjected to catalytic reforming by using a proper catalyst in the pyrolysis process, and reactions such as cracking, deoxidizing, aromatizing and the like are promoted, so that the selectivity and the yield of light aromatic hydrocarbon are remarkably improved, and an alternative scheme can be provided for producing liquid fuel and fine chemicals from non-petroleum resources. At present, the key point of lignite catalytic pyrolysis is to solve the problem of carbon deposition deactivation of a catalyst. The main reasons for carbon deposition are that (1) the acidic center on the surface of the catalyst can cause side reactions (polymerization, cyclization and aromatization) to generate macromolecules such as polycyclic aromatic hydrocarbon, which are difficult to diffuse out from micropores of the catalyst to form carbon deposition and cover active centers to block pore channels, and (2) a great deal of oxygen-containing functional groups and unsaturated hydrocarbons generated by pyrolysis of lignite with high oxygen content and high volatile are subjected to polycondensation reaction in the catalytic process to form heavy tar and carbon deposition precursors, and finally carbon deposition is formed. The traditional method for regenerating the carbon deposition catalyst is high-temperature calcination, but the molecular sieve catalyst particles are sintered and agglomerated in the high-temperature calcination process, and in addition, the carbon deposition combustion in the calcination process can generate local high temperature, so that the molecular sieve structure is changed, and the catalytic activity is reduced. Based on this, many students have made a great deal of study on solving the problem of carbon deposition. For example, patent publication No. CN121103413A discloses a method for improving the selectivity of light aromatic hydrocarbon in a biomass product by catalytic pyrolysis of a zeolite molecular sieve catalyst, which introduces mesopores into a molecular sieve by an alkali treatment or hard template method to improve mass transfer and reduce carbon deposition, patent publication No. CN120984319A discloses a modified ZSM-5 molecular sieve catalyst, a preparation method and application thereof, and the method promotes hydrogen transfer reaction of pyrolysis free radical fragments in a metal position to reduce carbon deposition by carrying metal modification. However, although the above method can improve the anti-carbon deposition capability of the catalyst, the phenomenon of rapid deactivation of the catalyst still exists. Therefore, catalyst regeneration is necessary to improve the economics of the overall process. Disclosure of Invention The invention aims to provide a regeneration method of a carbon deposition molecular sieve catalyst, which can solve the problem that the catalyst for preparing an aromatic hydrocarbon molecular sieve by catalytic pyrolysis of lignite is easy to be deactivated by carbon deposition and remarkably improves the catalytic activity of the regenerated catalyst. In order to achieve the aim, the invention adopts the following technical scheme that the regeneration method of the carbon deposition molecular sieve catalyst comprises the following steps: s1, collecting a carbon deposition molecular sieve catalyst after the reaction of preparing aromatic hydrocarbon by lignite catalytic pyrolysis, and grinding the carbon deposition molecular sieve catalyst to obtain carbon deposition molecular sieve catalyst powder; S2, placing the carbon deposition molecular sieve catalyst powder prepared in the step S1 into a low-pressure plasma generator for ashing regeneration treatment, wherein the treatment temperature is 200 o ℃ at the highest, and the atmosphere is O 2; And S3, taking the mass change of the catalyst as a basis for whether the regeneration process is finished or not, and judging that the low-pressure plasma ashing regeneration process is finished when the weight difference of the carbon deposition catalyst measured twice is less than 1% of the mass of the carbon deposition molecular sieve catalyst collected in the step S1. Preferab