Thermal balance sheet of plastic pyrolysis oil on a single cylinder DI engine Rupesh Lal Karn a , Suman Aryal a , Barsha Neupane a , Manish Koirala a and Laxman Palikhel a,∗ a Department of Automobile and Mechanical Engineering, Thapathali Campus, Institute of Engineering, Tribhuvan University, Thapathali, Kathmandu, Nepal ARTICLE INFO Article history: Received 07 Mar 2021 Received in revised form 17 Sep 2021 Accepted 21 Sep 2021 Keywords: High-grade plastic oil Thermal balance sheet Heat in jacket cooling water First law of thermodynamics Heat equivalent to brake power Abstract An internal combustion engine can be considered a thermodynamic open system. Investigation on blends of distilled plastic oil was performed on a constant speed diesel engine at various loading conditions. The thermal balance sheet was prepared concerning useful work i.e. heat equivalent to useful work, heat loss in jacket cooling water, heat loss in the exhaust gas, and unaccounted heat i.e. heat loss in radiation. Blends up to 20% by volume of various high-grade plastic fuels were used. The thermal balance sheet indicates that heat equivalent to brake power of 5PDB is higher than diesel at low load and 10PDB has higher HBP than diesel at high load. All blends of PDB indicate higher heat conversion into useful work. The exhaust gas temperature of all blends of high-grade plastic fuel is lower than that of diesel which shows a better conversion rate of produced heat in the cylinder into useful work. ©JIEE Thapathali Campus, IOE, TU. All rights reserved Abbreviations and acronyms 5 PDB : 5% Blend of High-grade plastic oil with 95% diesel 10 PDB : 10% Blend of High-grade plastic oil with 90% diesel 15 PDB : 15% Blend of High-grade plastic oil with 85% diesel 20 PDB : 20% Blend of High-grade plastic oil with 80% diesel 1. Introduction The increase in demand for natural petroleum resources has attracted the interest of many researchers to find a substitute for natural petroleum. Plastic being the byproduct of petroleum products, can be used to pro- duce petroleum-grade oil. Plastic undergoes thermal ∗ Corresponding author: laxmanpalikhel@ioe.edu.np (L. Palikhel) degradation in absence of oxygen to produce oil. Ther- mal degradation in absence of oxygen is thermal py- rolysis. Thermal pyrolysis followed by bypassing the gas with a catalyst is called catalytic pyrolysis. Catalyst commonly used are zeolite, silica-alumina, FCC cata- lyst, alumina, etc. [1] . On thermal pyrolysis of plastic, petroleum grade fuel is obtained which has the same fuel property as that of the diesel [2]. The end product of thermal pyrolysis depends upon the type of plastic feed. The presence of polyethylene increases alkane content, polypropylene increases alkene content and polystyrene increases aromatic content [3]. The oil obtained from thermal pyrolysis contains both the shorter and longer hydrocarbon chain. Oil obtained from thermal pyrolysis goes through fractional distillation to reduce the carbon chain. The distilled oil has good fuel quality and high energy content [4]. Fuel property of blends of plastic oil with diesel up to 20% by volume has comparative fuel property character as that of EN 590 diesel fuel standard. [5]. The engine was able to run with 100% waste plastic oil [6]. The waste plastic pyrolysis oil is a suitable fuel for a diesel engine, without any modification made on the engine, and it has the property equivalent to diesel R. L. Karn et al. / JIEE 2021, Vol. 4, Issue 2. Page 56