Comparative study on pyrolysis of Delonix Regia, Pinewood sawdust and their co-feed for plausible bio-fuels production

Abstract

Individual and co-feed pyrolysis of various weight percentages of two solid waste biomasses, have been carried out in a tubular reactor at 625 °C and 1 bar. Both biomasses considered herein are having average calorific values of 18.33 MJ/kg and 18.5 MJ/kg. Experiments are performed individually on both the biomasses and then the co-feed in the ratio of 25:75, 50:50, and 75:25 taken for co-pyrolysis study. Further to be noted that pyrolysis experiments of each case and their product analyses in addition to feed characterization have been done thrice. These results are presented individually for each run in addition to their average and standard deviation values. The biomass feedstock, bio-oil, and biochar are thoroughly characterized by extensive advanced characterization techniques such as thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectroscopy (GCMS), nuclear magnetic resonance (NMR), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) appropriately, as applicable for each case. The highest heating value of obtained pyrolytic bio-oil is from a co-feed ratio of 50:50 with an average HHV of 20.3 MJ/kg and having only 14.3 wt % of moisture content on average of three repetition experiments. The density of bio-oil obtained in all cases is approximately close to 1 g/cc, whereas their average viscosity varies between 2.07 and 3.61 mPa s. Thus, this study delivers that the rarely researched biomass considered for this study has almost similar potential to produce biofuels as that of extensively researched other biomass and their co-feed (1:1) pyrolysis is optimum for production of improved quality of pyrolytic bio-oil in terms of HHV, pH, density and moisture content.