Impacts of nickel supported on different zeolites on waste tire-derived oil and formation of some petrochemicals

Tuning the product distribution during the catalytic pyrolysis of waste tires: The effect of the nature of metals and the reaction temperature

“…However, despite the maturity of this process and its indubitable economic and environmental contributions, its greater expansion strongly depends on the potential use of its derived oil, which is often hindered by the physical-chemical complexity of the product mixture obtained. Consequently, a significant number of papers about waste tire pyrolysis have been published recently [7][8][9][10][11][12][13], which are primarily focused on the yield and selectivity toward certain reaction products present in the gas and/or liquid fraction.…”

“…The use of catalysts during pyrolysis has been one of the strategies that have been evaluated in order to drive the reaction toward the desired products. In this framework, zeolites have been the most studied catalysts [9][10][11][12][14][15][16][17][18][19][20], mainly with the objective of increasing the selectivity toward aromatic hydrocarbons. All investigations agree that properties such as (a) acidity/basicity, (b) pore channel structure, (c) size, and (d) Si/Al ratio in zeolites would affect the production of valuable hydrocarbons such as benzene, toluene, xylenes, ethylbenzene, and styrene.…”

Thermal Behavior, Reaction Pathways and Kinetic Implications of Using a Ni/SiO2 Catalyst for Waste Tire Pyrolysis

“…According to the results, the Ni/SiO2 catalyst could be an interesting alternative to obtain a pyrolytic oil enriched with cycloalkenes and/or monocyclic aromatic compounds (mainly BTX) at low temperatures. Besides, Ni-catalyst supported on SiO2 did not promote reactions conducting to the formation of polyaromatic compounds due to its low acidity, compared with bifunctional Ni-catalysts supported on zeolites [17]. This characteristic could enhance the catalyst stability as the coke deposits have been related to the formation of polycyclic aromatics and polar aromatics compounds [10][11][12].…”

“…Other transition metals have been demonstrated to be active for transforming complex mixtures of polymeric residues [13][14][15] and to produce oil with an upgraded composition [16][17][18]. In this regard, nickel showed to promote the activity of zeolites (HZSM-5, HMOR, HY, and HBETA) by enhancing the quality of TPO in reference to its fuel properties [17]. For example, when Ni/HZSM-5 and Ni/HMOR were used as catalysts for WT pyrolysis, a lighter TPO with a higher proportion of gasoline and kerosene and lower sulfur content was obtained.…”

“…In contrast, the Ni/HBETA and Ni/HY promoted heavier fractions with a high proportion of di-, poly-, and polar-aromatics compared to pristine zeolites. However, according to Namchot et al [17], both the channel structure and the acidic characteristics of zeolites governed the product distribution and sulfur removal, so that zeolite properties more than the metallic site strongly influenced catalytic behavior. Therefore, the specific role of Ni sites during the WT pyrolysis is not well understood as well as its kinetic and mechanistic implications remain unsolved.…”