Extraction and characterization of waste plastic pyrolysis oil for diesel engines

In this research work, the fuel extraction process from waste plastics through the thermal cracking method is explored. The pyrolysis process was carried out at a wide range of temperatures in the absence of oxygen. About 78% (w/w) of the liquid yield was extracted between the effective pyrolysis temperatures of 370 degrees C - 380 degrees C, resulting in a calorific value of 38.53 MJ/kg. The obtained plastic pyrolysis fuel was then characterized by thermogravimetric study, FTIR and GC-MS analysis. Thermogravimetric analysis indicates that the structures of natural plastic break at 200 degrees C and fully decompose at 300 degrees C. The presence of alkanes and aromatic components in the plastic pyrolysis fuel was confirmed through FTIR analysis. Further GC-MS studies on fuel samples have proven that hydrocarbon compounds exist within the C7-C40 range. Plastic pyrolysis fuel obtained from waste plastics is found to have similar fuel properties to diesel. The plastic pyrolysis fuel was tested in a single cylinder four stroke variable compression ratio diesel engine with different blends of plastic pyrolysis fuel and diesel ranging from 0% to 100% at varied engine loads ranging from 25% to 100%. The engine performance and exhaust emissions were studied and compared with conventional diesel fuel operation. The research revealed that the engine can operate on plastic pyrolysis fuel at full load, has a 6% improvement in brake thermal efficiency as well as 4% reduction in UBHC and 2% reduction of CO emissions, albeit NOx emissions were significantly greater. The results confirmed that plastic pyrolysis fuel could be a viable replacement option for diesel.

Automated summary

This research explores the process of extracting fuel from waste plastics through thermal cracking method, and finds that plastic pyrolysis fuel has similar fuel properties to diesel. The engine test results demonstrate that the plastic pyrolysis fuel can be used at full load with improved combustion efficiency and reduced emissions.