Mesoporous MCM-41, MCM-48, SBA-15, and pyrolysis char as catalysts for catalytic pyrolysis of waste tire

Abstract

Due to the fact that aromatic compounds and hetero-atoms such as nitrogen are present, tire-derived oil (TDO) is not suitable for direct uses in a vehicle engine. Additionally, char remaining from pyrolysis is highly obtained, but it has only a few applications. Therefore, the objectives were to (1) design catalysts for removal of heavy compounds in TDO, (2) study the effect of pore size and pore structure of selected catalysts, (3) upgrade pyrolysis char for using as catalyst, and (4) identify N-containing compounds for better understanding in further treatment. The result indicated that aromatic compounds (size 8-16 Å by average) were mainly in gas oil and vacuum gas oil fractions. The selected catalysts, like mesoporous materials, were thus suggested to handle these compounds. Subsequently, mesoporous Al-MCM-41 (33.1 Å) and Al-SBA-15 (60.5 Å) were used to study the effect of pore size whereas mesoporous Si-MCM-41 (hexagonal structure) and Si-MCM-48 (cubic structure) were used to study the effect of pore structure. As a result, the pore size of 33.1 Å and cubic structure gave better removal of heavy compounds, petrochemical productivity, and sulfur removal. Furthermore, pyrolysis chars With and without treatment well performed on improving lighter fractions from conversion of heavy portions. Moreover, identification of nitrogenous compounds in TDO was successfully accomplished using an effective GCxGC/TOF-MS. The detected species were classified into 10 groups. Interestingly, diazabicycloheptenes is a new group, firstly detected in TDO, owing to the high performances of GCxGC/TOF-MS on separation and detection of highly-complex mixtures.