Molecular sieve manufacturer explains the advantages of ZSM-5 molecular sieve
The thermal stability of ZSM-5 molecular sieve is very high, which is caused by the five-membered ring with stable structure and high silicon-aluminum ratio in the framework. For example, after the sample is calcined at around 850°C for 2 hours, its crystal structure remains unchanged, and it can even withstand a high temperature of 1100°C. ZSM-5 is one of the most thermally stable zeolites, therefore, it is particularly suitable for high temperature processes. For example, when it is used as a hydrocarbon cracking catalyst, it can withstand high temperatures during catalyst regeneration.
ZSM-5 molecular sieve has good acid resistance, it can resist various acids except hydrofluoric acid.
Water vapor stability
When other zeolites are exposed to water vapor and heat, their structures are often destroyed, resulting in irreversible deactivation. Using ZSM-5 as a catalyst for methanol conversion (water is one of the main products) suggests that ZSM-5 is a Water vapor has good stability. The crystallinity of HZSM-5 and HY zeolite was about 70% of that of the fresh catalyst after steam treatment at 540 °C with a partial pressure of 22 mmHg for 24 h, but the framework of HY zeolite was almost completely destroyed under the same conditions.
ZSM-5 has high silicon-aluminum ratio and low surface charge density, and water is a highly polar molecule, so it is not easy to be adsorbed by ZSM-5. Although the diameter of water molecule is smaller than that of n-hexane, the adsorption of n-hexane by ZSM-5 The capacity is generally greater than that of water.
Not easy to deposit carbon.
The effective shape and size of the orifice plate of ZSM-5 and the curvature of the channels prevent the formation and accumulation of huge condensates, and at the same time, there are no cavities (cages) larger than the orifices in the frame of ZSM-5, which restrict the The formation of large condensed molecules of side reactions, thereby reducing the possibility of carbon deposition in the ZSM-5 catalyst. ZSM-5 prevents alkyl aromatic hydrocarbons from entering the pores, so it cannot continue to react in smaller pores during the reaction process, and coke is formed by final polycondensation. Therefore, the carbon deposition rate of ZSM-5 is much slower than that of Y-type and mordenite. almost two orders of magnitude. The carbon capacity of ZSM-5 molecular sieve is also higher.
Hunan Providence New Materials Co., Ltd is a professional molecular sieve manufacturer which can provide USY zeolite, NaY zeolite, REY zeolite, ZSM-5 zeolite, welcome to consult.