Development of Sustainable Biofuel from Seed Waste Using Pyrolysis and Its Sustainability in the Compression Ignition Engine Application

Abstract

In recent decades, conventional diesel engines have faced serious challenges due to the depletion of fossil fuel sources. The current research investigates the feasibility of using waste Acacia nilotica (AN) seed pyrolysis oil as fuel in diesel engines. The pyrolysis investigations were carried out in a batch-type reactor at temperatures ranging from 400 °C to 650 °C, a heating rate of 10 °C/min, and feedstock sizes ranging from 0.2 to 1.7 mm. The maximum oil yield of 49% was obtained at 500 °C with an optimum particle size of 0.5 mm. The characterization of bio-oil was estimated with the help of Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1HNMR), and gas chromatography-mass spectrometry (GC-MS) analysis. FTIR analysis detected aliphatic functional groups in bio-oil. GC-MS analysis determined phenolic, acetic, and cresol compounds in pyrolysis oil. Bio-oil contains 64.78% aliphatic hydrocarbons (HC), according to 1HNMR. Blends of AN and diesel were studied in diesel engines to investigate engine parameters, and the findings were compared to standard diesel. Under full load conditions, the efficiency of the AN10 (10% AN seed pyrolysis oil + 90% diesel) blend was discovered to be 32.8%, which is 2.3% lower than normal diesel, and oxides of nitrogen (NOx) and smoke emissions were low. The findings confirmed that up to 30% of the AN blend can substitute for diesel in compression ignition (CI) engine applications.