CATALYTIC CONVERSION OF USED OIL TO HYDROCARBON FUELS IN A FRACTIONATING PYROLYSIS REACTOR

Pyrolysis of used sunflower oil was carried out in the presence of dif ferent amounts of HZSM-5 at 400 and 420 degrees C in a reactor equippe d with a fractionating packed column, the length of which was varied. The products consisted of gaseous and liquid hydrocarbons, acids, CO, CO2, water, and coke. The compositions of the gaseous and liquid produ cts were studied by gas chromatography. The product yields and composi tions were affected by catalyst content, temperature, and column lengt h. Nearly complete conversion (96.6%) of the used oil and the maximum liquid hydrocarbon yield (33%) were obtained at the highest temperatur e (420 degrees C), highest catalyst content (20%), and the lowest colu mn length (180 mm) employed. The aromatic hydrocarbon contents of the liquid hydrocarbon products, which consisted of hydrocarbons of gasoli ne range, were in general lower than those obtained using fixed bed re actors but increased parallel to the increase in catalyst content. Add itional thermal reactions taking place in this type of reactor increas ed with the increase in column length. Although the total conversion a nd total liquid hydrocarbon yields were influenced adversely by these reactions, liquid products with higher isomeric hydrocarbon contents w ere obtained with longer columns.