Effect of antioxidant tetraethylenepentamine on pyrolysis, oxidation, and emission behavior of jatropha biodiesel

Antioxidants, such as tetraethylenepentamine (TEPA), are generally used to enhance the oxidation stability of biodiesel, but their impact on the combustion and emissions of biodiesel remains unclear. In this study, the effect of TEPA addition on the pyrolysis, oxidation, and pollutant emission characteristics of jatropha biodiesel, were investigated via employing thermogravimetry coupled with Fourier-transform infrared spectroscopy and mass spectrometry (TG-FTIR-MS) analysis combined with ReaxFF molecular dynamics simulations. The results indicate that TEPA and its pyrolysis products consume reactive radicals produced during the pyrolysis process of biodiesel and thereby slightly inhibit the pyrolysis reactivity. In contrast, under oxidation condition, the addition of TEPA to biodiesel produce more ·OH radical, which can accelerate the oxidation process and promote the formation of formaldehyde, carbon dioxide and water. The premixed flame experiments indicate the addition of TEPA leads to 21.27 % reduction in CO emissions but 22.09 % increase in NO emissions. Moreover, the morphological analysis of soot particles reveals that TEPA addition to biodiesel increased the particle diameter by about 5 nm. Though TEPA can promote the combustion of biodiesel, its negative impact on the pollutant emissions should be taken into consideration for practical application.