Fuel products from pyrolysis of physic nut Jatropha Curcas L. waste

Abstract

This research investigated the effects of different operating conditions, such as sample size, final temperature and hold times, on properties of solid chars, liquid bio-oil and gas prepared by vertical fixed bed pyrolysis of extracted Physic nut (Jatropha curcas L.) waste. The size fraction of Physic nut residue was varied from 0.43-0.50, 0.50-0.85, 0.85-1.80 and 1.80-3.60 mm. The variable studied was final temperature (400, 500, 600, 700 and 800℃) and retention time (0.25, 2 and 4 hours) in isothermal and dynamic pyrolysis. The results showed that suitable pyrolysis condition was 800℃ for 15 minutes with 90.01% fixed carbon, 24.23% yield, 4.34% volatile matter and 4.87% ash. Physic nut waste char was activated by physical and chemical means using carbondioxide gas and by alkaline solution such as KOH and NaOH, respectively. Investigating parameters were activation temperature, activation time particle size of Physic nut residue char, and ratio of char per alkaline solution. The experimental results revealed that the suitable condition for physical activation was at 600℃ for 1 hour using char with the size of 0.43-0.50 mm; whereas the appropriate condition for chemical activation using either KOH or NaOH as an activating agents was at 700℃ for 1 hour using char with same size. Activated carbon prepared from KOH however gave higher quality than that from NaOH owing to stronger alkaline of KOH solution. The maximum liquid product of 21.35% was observed at the pyrolysis temperature of 900℃ for 1 hour under dynamic heating and 61.54% under isothermal heating at 500℃. The bio-oil 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. Liquid tar from pyrolysis are complex mixture of condensable hydr℃arbons which include single ring to five ring aromatic compounds along with other oxygen containing hydr℃arbons. Tar can be eliminated by thermal cracking or by the use of catalysts. The catalytic gasification pr℃ess is an attractive technological alternative to deal with tar and to produce high yield of syn-gas. This research has proved the usefulness and effectiveness of calcined olivine and nickel based steam reforming catalysts on decreasing tar yield and achieve high conversion. Olivine and Ni/Olivine were chosen as a catalyst because of their activity in tar cracking. Phosphor olivine (LiFePO4) support was synthesized by co-precipitation method. The Ni/Olivine was carried out by wet impregnation of synthesized olivine supports with Ni(NO3)2 solution. Olivine and 5%Ni/Olivine displayed excellent reforming capability when applied to in-situ gasification/reforming of glycerol waste. Complete conversion of carbon and hydrogen in materials to product gas as well as superior selectivity of preferred gas species may be achieved with catalyst at 600℃