Multi-attribute decision-making approach for Aegle marmelos pyrolysis process using TOPSIS and Grey Relational Analysis: Assessment of engine emissions through novel Infrared thermography

This research focuses on the selection of the optimum process parameters for Aegel marmelos (AM) pyrolysis experiment based on multi-objective decision-making techniques. This investigation presents the optimization report for obtaining maximum pyrolysis oil from AM de-oiled seed cake through thermochemical conversion (pyrolysis) process. The pyrolysis process has been conducted according to L-27 orthogonal array with chosen input control factors such as pyrolysis temperature (degrees C), heating rate (degrees C/min) and biomass particle size (mm). The output response parameters measured are the bio-oil yield, bio-char yield and biogas yield. The multi-objective decision-making approach namely Technique for order preference by similarity to ideal solution (TOPSIS) and Grey relational analysis (GRA) techniques are employed to determine the optimum pyrolysis process parameters to maximize the yield of AM bio-oil. The optimized values of pyrolysis temperature (PT), heating rate (HR) and feedstock particle size (PS) are 600 degrees C, 10 degrees C/min and 0.6 mm. At peak engine loading condition, 20% AM bio-oil + 80% diesel fuel blend (AM20) emit lower carbon dioxide (CO2 = 8.68%) and oxides of nitrogen (NOx = 1401 ppm) emissions as compared with diesel (D) CO2 (10.33%) and NOx (1511 ppm) emissions. The association between exhaust gas temperature and NOx emission was inferred using a novel approach of thermal imager by sensing the infrared rays from the hot surface of the exhaust port. Infrared thermal images are captured during the engine operations fuelled with bio-oil at the optimum pyrolysis conditions concluded by TOPSIS and GRA results (PT = 600 degrees C, HR = 10 degrees C/min and PS = 0.6 mm). According to the thermal imaging result, AM20 blend produces the lower amount of NOx emissions compared with neat diesel and it is suggested that AM bio-oil can be used as engine fuel instead in order to preserve the ecosystem stability and biodiversity. (C) 2019 Elsevier Ltd. All rights reserved.