Catalytic Cracking of n-Hexadecane Using Carbon Nanostructures/Nano-Zeolite-Y Composite Catalyst

Abstract

Zeolite-based catalysts are usually utilized in the form of a composite with binders, such as alumina, silica, clay, and others. However, these binders are usually known to block the accessibility of the active sites in zeolites, leading to a decreased effective surface area and agglomeration of zeolite particles. The aim of this work is to utilize carbon nanostructures (CNS) as a binding material for nano-zeolite-Y particles. The unique properties of CNS, such as its high surface area, thermal stability, and flexibility of its fibrous structure, makes it a promising material to hold and bind the nano-zeolite particles, yet with a contemporaneous accessibility of the reactants to the porous zeolite structure. In the current study, a nano-zeolite-Y/CNS composite catalyst was fabricated through a ball milling approach. The catalyst possesses a high surface area of 834 m2/g, which is significantly higher than the conventional commercial cracking catalysts. Using CNS as a binding material provided homogeneous distribution of the zeolite nanoparticles with high accessibility to the active sites and good mechanical stability. In addition, CNS was found to be an effective binding material for nano-zeolite particles, solving their major drawback of agglomeration. The nano-zeolite-Y/CNS composite showed 80% conversion for hexadecane catalytic cracking into valuable olefins and hydrogen gas, which was 14% higher compared to that of pure nano-zeolite-Y particles.

Catalytic Activation of Polyethylene Model Compounds Over Metal‐Exchanged Beta Zeolites

“…Heterogeneous catalytic routes for deconstruction of polymers including polyethylene are appealing due to the ease of separation of products from the catalyst, enabling continuous operation of heterogeneous catalytic reactors. Many heterogeneous catalysts for polyethylene decomposition have been studied, but most proposed pathways require temperatures in excess of 500 °C, [8] co-processing with H 2 , [9][10][11][12][13][14][15] and/or precious metal catalysts. [9][10][11]16] Strategies involving H 2 co-processing, often referred to as hydrocracking, are partic-ularly notable as they truncate polymer chains by replacing CÀ C bonds with CÀ H bonds.…”

“…Such a process, if operable at low temperatures (� 300 °C), would dramatically attenuate energy and resource demands of plastics decomposition. Deactivation of depolymerization catalysts with time on stream is common to many reports, [8,13,17] and identification and development of deactivation-resistant catalysts is important for depolymerization process scalability.…”