Production of Bio-char from Jatropha-seed Cake via Torrefaction
Date Issued
2012
Date
2012
Author(s)
Hsu, Tsung-Chi
Abstract
Torrefaction is a thermal treatment used to enhance the properties of fuels. In this study, Jatropha curcas L. seed cake after mechanically expelling ectraction of oil (denoted as Jatropha pressed cake or JPC) and the de-oiled JPC after further solvent extraction of residual oil using n-hexane (symboled as JDPC), were examined for their torrefaction performances. The thermogravimetric analysis (TGA) were employed to elucidate the thermal decomposition behaviors of JPC and JDPC. Temperatures with acceptable mass loss of 5-10% of JPC in TGA were in the range of 260-310 °C, suggesting the further tests of the torrefaction at 260, 280 and 300 °C. The torrefaction temperature (Tr) and time (tr) play important roles on the production yield of bio-char. The tr employed were 10 to 60 min. During the torrefaction at a setting temperature Tr, the biomass further lost its mass. The characteristics of torrefied products were measured and assessed. Proper torrefaction conditions were elucidated, considering the balance of enhancing the energy density (ED) while retaining the yield (Ym). The results indicate that at Tr= 260, 280 and 300 °C, ED values of torrefaction products of JPC are 1.25, 1.29 and 1.30, while those of JDPC are 1.28 1.37 and 1.39, respectively. The high heating values per mass in dry basis (HHMD) for the cases using JPC and JDPC are about 5,000-6000 kcal kg-1. The fixed carbon content (MFC) increases after torrefaction, enhancing its coal-alike property. The MFC is highly and positively correlated with HHMD. Employing the appropriate conditions of Tr = 280 °C and tr = 40min, the torrefied products containing negligible sulfur, ash of 9.27 wt.% and HHMW of 5700 kcal kg-1 meet the D quality of coal standards of Taiwan Power Co. with sulfur < 1.1 wt.%, ash < 16 wt.% and HHMW >5000 kcal kg-1.
Subjects
torrefaction
biomass waste
Jatropha curcas L.
bio-char
Type
thesis
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