Manufacture of Jatropha-oil Biodiesel via Semi-continuous Ultrasonic Irradiation Transesterification
Date Issued
2015
Date
2015
Author(s)
Tian, Sz-Ying
Abstract
In this study, jatropha oil was used in a two-stage transesterification process with assistance of ultrasound irradiation (UI) to manufacture jatropha-oil biodiesel (JOB). The main properties measured inclued, acid value (AV), water content (mW), kinematic viscosity (KV), density (ρO), heating value (H) and cold filter plugging point (CFPP). In the first-stage of esterification, the reaction conditions were set using including molar ratio of isopropanol (IPA) to raw jatropha oil (JOR) (MIPA/JOR) = 5, reaction temperature (TE) = 120 ℃, volume of H2SO4 (VH2SO4) = 1.02 mL, injection flow rate of mixture of IPA and H2SO4 (QE) = 1.5 mL/min, reaction time at constant TE (tE) = 59.08 min and input JOR = 200 g. In order to observe the influence of alcohols on properties and yield (YF) of transesterification, the second-stage of transesterification was constracted by using either IPA or methanol (MOH) in different transesterification reaction temperature (TT), molar ratio of alcohol to product of esterification (JOE) (MIPA / JOE or MMOH / JOE) and reaction time (tT). Finally, the optimal temperature, molar ratio and reaction time of the transesterification reaction could be found. According to experimental result, AV of JOB with IPA is slightly higher than that of JOE. The AV of JOB decreases with increasing MIPA / JOE. At the conditions of TT = 80 ℃ and tT = 180 min with the optimal MIPA / JOE of 9, the yield is 96.06 % with AV = 0.429 mg KOH/g, KV = 4.01 mm2/s, ρO = 872.47 kg/m3, H = 29.88 MJ/kg and CFPP = -3.5 ℃. The best AV (lowest) and yield (highest) are achieved at TT = 80 ℃ with other properties satisfied with CNS 15072 standards. The best reaction time is 90 min. As reaction time further increases, AV rises a little and yield drops slightly. For transesterification with MOH at TT = 60 ℃, MMOH / JOE = 6 is the optimal condition. There is no evident impact on increasing yield and reducing AV by increasing MMOH/JOE. The oils made by transesterification with reaction times longer than 10 min are similar. At the conditions of TT = 60 ℃, MMOH / JOE = 6 and tT = 10 min, the biodiesel YF is 97.08 % with AV = 0.097 mg KOH/g, KV = 4.40 mm2/s, ρO = 881.50 kg/m3, H = 38.14 MJ/kg and CFPP = -1 ℃. Compared with IPA, the use of MOH needs shorten tT, lower TT and less MMOH / JOE. It produces JOB with lower AV, but higher CFPP. The properties and YF by using MOH or IPA as alcohol for esterification are similar. Because IPA can come from the waste stream, one may thus use IPA in the first-stage esterification, while MOH employ in the second-stage transesterification. This not only achieves waste recycling but also satisfies with CNS 15072 standard.
Subjects
Biodiesel, Jatropha oil, Two-stage transesterification, Methanol, Isopropanol, Ultrasound
SDGs
Type
thesis
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