Stability Assessment of Regenerated Hierarchical ZSM-48 Zeolite Designed by Post-Synthesis Treatment for Catalytic Cracking of Light Naphtha

Abstract

Hierarchical ZSM-48, a one-dimensional pore system zeolite with the presence of mesopores, was obtained by post-synthesis alkaline and acid treatments. Hierarchical ZSM-48 exhibited excellent hexane cracking activity compared to parent ZSM-48, which can be attributed to better diffusion as a result of the created mesoporosity. Moreover, the post-synthesis treatment allowed for manipulation of the distribution of active sites. Consequently, better stability and higher propylene selectivity were accomplished. The spent catalyst was regenerated by removing the deposited coke from the pores, and the regenerated catalyst was characterized again to investigate the recyclability of the hierarchical structure achieved. Parent ZSM-48 showed the same textural and acidic properties after regeneration, while the structure of the post-treated sample suffered from serious defects. The defects severely decreased the number of active sites as measured by pyridine Fourier transform infrared spectroscopy and caused major structural collapse as observed by scanning electron microscopy and transmission electron microscopy. 65 preparing hierarchical zeolites, especially because the structure 66 of these hierarchical zeolites is suffering from serious defects. 67 The durability and preservation of zeolite properties are highly 68 required for the catalyst, which will be used in FCC or any 69 process because the calculations of material balance of 70 separation units will be based on product selectivity.

Glycerol to Solketal for Fuel Additive: Recent Progress in Heterogeneous Catalysts

“…A higher acetone to glycerol ratio was obtained over a higher acetone to glycerol ratio. Both desilication and dealumination are very effective in improving the catalyst stability of zeolite based catalyst [66][67][68].…”

Peculiarities of Glycerol Conversion to Chemicals Over Zeolite-Based Catalysts

“…The low-cost fabrication of hierarchical zeolites with different topologies were started with three-dimensional (3D) medium pore ZSM-5 (MFI) (Muraza et al, 2013, 2014; Bawah et al, 2018), 3D large Beta (BEA) and 3D large pore FAU. Later, some one-dimensional pore zeolites such as MTW (Sanhoob et al, 2016), MTT (Muraza et al, 2013, 2014), TON (Jamil et al, 2018), and MRE (Ahmed et al, 2017) were also reported elsewhere.…”

“…In addition to activation procedures, stability during chemical reactions, and possible regeneration are expected to suppress the catalyst cost. Ahmed and coworkers reported the decrease of crystallinity of hierarchical MRE zeolite (i.e., ZSM-48) (Ahmed et al, 2017). Typically, the crystallinity of zeolite-based catalysts decreased during regeneration.…”

Nanoporous Sn-Substituted ZSM-48 Nanostructures for Glucose Isomerization

“…37 Up to date, it has been typically applied in n-heptane hydroisomerization, 38 methanol to hydrocarbons, 39 and catalytic cracking of light naphtha. 40 Due to the limited use of the one-dimensional framework of ZSM-48, there have been a few reports demonstrating its catalytic applications, especially when involving with a bulky molecule, such as glucose valorization. The intriguing strategy to overcome this restriction is to introduce the additional larger pores in the zeolite framework, which might open the opportunity of using one-dimensional ZSM-48 in many reactions in the future.…”

“…In particular, the ZSM-48 (*MRE topology) consists of a one-dimensional framework formed by 10-membered ring pores in the diameters of ∼5.6 × 5.3 Å . Up to date, it has been typically applied in n -heptane hydroisomerization, methanol to hydrocarbons, and catalytic cracking of light naphtha . Due to the limited use of the one-dimensional framework of ZSM-48, there have been a few reports demonstrating its catalytic applications, especially when involving with a bulky molecule, such as glucose valorization.…”