Catalytic Cracking of Triglyceride-Rich Biomass toward Lower Olefins over a Nano-ZSM-5/SBA-15 Analog Composite

Aromatics and cyclic-hydrocarbons are the significant components of jet fuel with high energy-density. However, conventional technologies for bio-fuel production cannot produce these products without further aromatization and isomerization. In this work, renewable liquid fuel with high content of aromatics and cyclic-hydrocarbons was obtained through aqueous catalytic conversion of biomass sorbitol over Ni-HZSM-5/SBA-15 catalyst. Texture characteristics of the catalyst were determined by physisorption of N2, which indicated its bimodal pore structures were microporous (HZSM-5, pore width: 0.56 nm) and mesoporous (SBA-15, pore width: 8 nm). The surface acidity included weak and strong acid sites, predominantly Lewis type, and was further confirmed by the NH3-TPD and Py-IR analysis. The catalytic performances were tested in a fixed-bed reactor under the conditions of 593 K, WHSV of 0.75 h

Section: Catalyst Characterizationmentioning

confidence: 99%

Jet-Fuel Range Hydrocarbons from Biomass-Derived Sorbitol over Ni-HZSM-5/SBA-15 Catalyst

Weng

Qiu

et al. 2015

“…Then the unreacted precursors are converted to ordered mesoporous SBA-15 by adding surfactant solution and followed by hydrothermal treatment at 200 • C for 24 h. The ZSM-5@SBA-15 zeolite exhibited superior catalytic activity due to its medium acid sites, improved molecular transport efficiency resulting from the hierarchical pore structure and good hydrothermal stability. This special morphology effectively suppressed the secondary reactions among primarily generated light alkenes, thus providing higher light alkene selectivity (93.2%) in the catalytic cracking of triglyceride-rich biomass [29,40].…”

Section: Zeolitic Composites Of Zsm-5 and Other Materialsmentioning

confidence: 99%

Strategies to Enhance the Catalytic Performance of ZSM-5 Zeolite in Hydrocarbon Cracking: A Review

Yang

Yan

2017

ZSM-5 zeolite is widely used in catalytic cracking of hydrocarbon, but the conventional ZSM-5 zeolite deactivates quickly due to its simple microporous and long diffusion pathway. Many studies have been done to overcome these disadvantages recently. In this review, four main approaches for enhancing the catalytic performance, namely synthesis of ZSM-5 zeolite with special morphology, hierarchical ZSM-5 zeolite, nano-sized ZSM-5 zeolite and optimization of acid properties, are discussed. ZSM-5 with special morphology such as hollow, composite and nanosheet structure can effectively increase the diffusion efficiency and accessibility of acid sites, giving high catalytic activity. The accessibility of acid sites and diffusion efficiency can also be enhanced by introducing additional mesopores or macropores. By decreasing the crystal size to nanoscale, the diffusion length can be shortened. The catalytic activity increases and the amount of carbon deposition decreases with the decrease of crystal size. By regulating the acid properties of ZSM-5 with element or compound modification, the overreaction of reactants and formation of carbon deposition could be suppressed, thus enhancing the catalytic activity and light alkene selectivity. Besides, some future needs and perspectives of ZSM-5 with excellent cracking activity are addressed for researchers' consideration.

“…Despite the great success of zeolites in the application for fluid catalytic cracking (FCC), the diffusion limitations have been recognized as a major problem that needs to be solved, especially when processing low quality feedstocks such as heavy oils or biogenic resources. In this area, MZC materials not only help to alleviate the diffusion limitations and to increase the accessibility of acid sites but also help to pre-crack bulky molecules into intermediates that could then enter the pores of zeolites and react on strong acid sites [13,14,31,39,41,50,54,62,64,[85][86][87][88][89][90].…”

Section: Catalytic Crackingmentioning

confidence: 99%

“…85%) while commercial ZSM-5 reaches only about 62%. Furthermore, the performance of the ZSC-24 composite with respect to commercial ZSM-5 and Al-SBA-15 has been evaluated in the cracking of biogenic feedstock, i.e., waste cooking oil under FCC conditions [85]. It was found that the ZSC-24 catalysts are superior, producing the remarkably higher selectivity toward C 2 -C 4 olefins than commercial ZSM-5 and Al-SBA-15 ( Table 1).…”

Section: Catalytic Crackingmentioning

confidence: 99%

Micro/Mesoporous Zeolitic Composites: Recent Developments in Synthesis and Catalytic Applications

Armbruster

Martin

2016

Self Cite

Micro/mesoporous zeolitic composites (MZCs) represent an important class of hierarchical zeolitic materials that have attracted increasing attention in recent years. By introducing an additional mesoporous phase interconnected with the microporosity of zeolites, a hierarchical porous system of MZCs is formed which facilitates molecular transport while preserving the intrinsic catalytic properties of zeolites. Thus, these materials offer novel perspectives for catalytic applications. Over the years, numerous synthesis strategies toward the formation of MZCs have been realized and their catalytic applications have been reported. In this review, the three main synthesis routes, namely direct synthesis using zeolite precursors, recrystallization of zeolites, and zeolitization of preformed mesoporous materials are thoroughly discussed, with focus on prior works and the most recent developments along with prominent examples given from the literature. In addition, the significant improvement in the catalytic properties of MZCs in a wide range of industrially relevant reactions is presented through several representative cases. Some perspectives for the future development of MZCs are also given.