Abstract:
Tire-derived oil usually consists of small amounts of petrochemicals, some large aromatic hydrocarbons and sulfur compounds. In order to improve the quality of tire-derived oil. catalysts are necessary in pyrolysis process. This work was divided into two parts. In the first part, the effect of acid density of mesoporous MCM-48 in waste tire pyrolysis was investigated. In the second part, mesoporous SiMCM-48 was placed as a lower bed catalyst (first layer) while a zeolite was placed consecutively as an upper bed catalyst (second layer). The effects of zeolites properties; that are. acidity (HBETA and HY) and pore size (HZSM-5 and HBETA), were investigated. The results showed that using Si-MCM-48 can remove the large aromatic hydrocarbons and sulfur compounds in tire-derived oil more greatly than the Al-MCM-48 catalysts. Moreover, the decreasing Si/Al ratio of Al-MCM-48 catalysts was found to enhance the sulfur removal in oils. Therefore, large molecules in tirederived oil can be handled by using mesoporous Si-MCM-48 whereas the Bronsted acid sites of Al-MCM-48 are necessary for sulfur removal ability of catalysts. Additionally, for the uses of double beds of catalysts, it was found that HBETA used in the second layer that has a lower acidity provided a higher concentration of petrochemicals than HY. and also provided a formation of poly-aromatic hydrocarbons. On the other hand, HZSM-5 that has a medium pore used in the second layer provided a higher concentration of petrochemicals than HBETA and HY. and decreased poly-aromatic hydrocarbons. Therefore, the double layer of Si-MCM-48/HZSM-5 gave the highest concentration of petrochemicals and reduction of large molecules among all catalysts.
