Experimental investigation and kinetics of tomato peel pyrolysis: Performance, combustion and emission characteristics of bio-oil blends in diesel engine

Abstract

Pyrolysis of tomato peel waste in an indigenous Auger reactor is reported. Tomato peel was subjected to elemental analysis and physicochemical characterisation. The higher heating value of the tomato peel was estimated to be 22.50 MJ kg−1. Thermogravimetric analysis of tomato peel was performed to estimate the temperature of pyrolysis process. Thermal cracking of tomato peel was carried out at different temperatures ranging from 450 °C to 650 °C. The bio oil yield was found to 14%, 17.5%, 32%, 40% and 36% at 450 °C, 500 °C, 550 °C, 600 °C and 650 °C respectively. Kinetic modelling of the tomato peel pyrolysis was performed with three different model free methods to evaluate the activation energy. The activation energy of tomato peel pyrolysis at different heating rates, 5 °C min−1, 10 °C min−1, 15 °C min−1, 20 °C min−1 and 25 °C min−1 were reported to be 112.7 kJ mol−1, 113.85 kJ mol−1 and 234.47 kJ mol−1 respectively by Kissinger, Kissinger Akahira Sunose and Ozawa Flynn Wall models. Tomato peel oil was subjected to Gas chromatography - Mass spectroscopy and Fourier transform infrared spectroscopy analysis to determine the compounds and functional groups. The kinematic viscosity of the tomato peel oil was found to be 11.82 cSt. The flash point of the tomato peel oil was estimated to be 94 °C. Different blends of tomato peel oil and diesel were subjected to testing in a 4-stroke water cooled open chamber diesel engine to evaluate the performance and emission characteristics analysis. The Brake thermal efficiency of 5% blend of tomato peel oil was estimated to be 31.5% under full load condition. Carbon Monoxide emissions of tomato peel oil blends were found to be lesser in comparison with diesel fuel. Techno-economic analysis of the tomato peel pyrolysis was also reported.