Pyrolysis of physic nut (Jatropha curcas L.) residue under isothermal and dynamic heating processes

Pyrolysis of physic nut residues was conducted under isothermal and dynamic heating conditions in a vertical fixed bed type reactor at final temperature of 500, 700 and 900 degrees C under N-2. The solid, liquid, and gas products were in the ranges of 26.94-29.04, 9.43-21.36, 51.70-61.54 wt% for slow pyrolysis, while those attained from rapid condition were 11.16-15.25, 15.00-23.43, and 61.3273.84 wt%, respectively. Results indicated that char decreased with increasing temperature and hold time. Char with highest fixed carbon of 85.32% with relatively low volatiles of 9.28% was obtained by pyrolysis at 900 degrees C for 60 min. Release of volatile matter led to development of char porous structure. The maximum liquid product of 21.35% was observed at the pyrolysis temperature of 900 degrees C for 60 min under dynamic heating and 61.54% under isothermal heating at 500 degrees C. Decreasing hold time to 15 min caused 2 times decrease of liquid yields. The liquid product mainly consisted of several fatty acids such as oleic acid, palmitic acid and lignoleic acid in the range of 15-19%, 40-45%, and 25-34%, respectively. Increase in temperature and hold time lead to greater production of hydrogen, carbon monoxide, and light hydrocarbons. Mode of heating displayed significant effect to the product distribution, LHV and H-2/CO ratio. Higher LHV values were obtained at 900 degrees C under rapid pyrolysis condition. Mole ratio of H-2/CO close to unity was found in the case of pyrolysis at 900 degrees C for both slow and rapid trials. The LHV obtained from slow processes were 7.8-15.0 MJ/Nm(3) while those from rapid runs were 14.8-17.2 MJ/Nm(3).