Thermo catalytic Conversion of Waste Engine oil to Fuel and Chemicals

Abstract

newline Waste management is a serious issue worldwide. Tones of non-biodegradable wastes such as waste plastics and waste engine oil are produced every day. The direct disposal of these wastes into the environment creates serious problems which are faced by different countries now a day. Thermochemical conversion is one of the possible technologies which can convert waste to energy in the form of solid, liquid, and gas. In the present investigation, waste engine oil (WEO) was selected as raw material. Initially, the WEO was characterized and confirmed the change in the characteristic properties compared to fresh engine oil. The effect of temperature in the thermal degradation using TGA at three heating rates showed that the WEO active pyrolytic zone laid between 200 oC to 465 oC. The maximum degradation was 98.86 % with a char yield of 1.135 % at 10 oC min-1. As the heating rate increased, the rate of degradation was reduced with increasing the char yield. The thermal degradation kinetics and thermodynamic parameters were calculated using Coats-Redfern method and assuming that the degradation followed 1st order reaction. The thermal pyrolysis of WEO was done within the temperature range of 450 oC to 575 oC which resulted in a higher yield of pyrolytic oil (76.73 %) at 550 oC. The pyrolytic oil was having calorific value of 42.42 MJ kg-1 and a viscosity of 18.21 cSt which is a composition of 32.97 % alkanes, 7.97 % cycloalkanes, 11.9 % alkenes, 4.78 % PAH and 41.21 % aromatic compounds. It was observed that thermal pyrolysis reduced the concentration of heavy metal present in the feed sample except for Ti, Cr, Sr, Co, Al, and As. The morphological and elemental analysis of thermal pyrolytic char indicated the use of char as a catalyst as it contains a higher amount of Ca.