利用異丙醇以超音波輔助程序產製痲瘋樹籽油生質柴油之研究

Application of ultrasonic irradiation and utilization of isopropanol to manufacture jatropha-oil biodiesel

鄧軒(Syuan Teng)

指導教授 ： 張慶源

國立臺灣大學/工學院/環境工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.10908

摘要

本研究分為兩部分:第一部分探討利用異丙醇(isopropyl alcohol, IPA)於超音波(ultrasonic irradiation, UI)輔助程序進行痲瘋樹籽油(簡稱痲瘋油, JO)之酸催化酯化。探討酯化反應溫度(T)與醇油比(M/O in mol/mol)對於酸價(AV)、密度(ρLO)、動黏度(KV)、生質柴油轉化率(YF)、異丙醇回收量、能源消耗等之影響，並找出最適之酯化反應溫度及醇油比，並以該條件進行後續第二部分之鹼催化轉酯化反應。針對轉酯化反應則探討反應溫度、醇油比、反應時間對於各項油品特性之影響，並找出最適之轉酯化條件。此先酯化再轉酯化之程序稱為兩階段式或兩步驟生質柴油產製程序。
酯化反應之研究結果顯示利用超音波(UI)輔助系統於酸催化酯化反應時，增加醇油比可有效降低油品之酸價，當T=120 ℃並在M/O=5時可將酸價由JO原料油之36.4降低至0.4 mg KOH/g以下，其自由酯肪酸之轉化效率YA為37.4%以上。並可知當溫度高於且接近異丙醇之沸點(82.3 ℃)時，例如在100及120 ℃ 時可將酸價皆降至0.2 mg KOH/g以下，生質柴油轉化率(YF)亦可達到71.4-75.5 %。在各特性之考量下選擇120 ℃為酯化反應之溫度。
轉酯化反應則利用酯化反應所得到之最適醇油比及反應溫度進行後續之研究。當T=80 ℃及t=20 min, 轉酯化反應之最適醇油比為9：1，此時生質柴油轉化率可達到95.87 %，酸價、密度、動黏度分別為95.87 %，0.688 mg KOH/g，892.5 kg/m3，9.548 mm2/s；若超過此醇油比則再增加IPA含量之效果有限。在此反應溫度時可看出在反應時間至20 min時，其反應幾乎已達完全。故增長反應時間對各項特性之效過不顯著，故選擇20 min為轉酯化反應之反應溫度。本研究使用IPA代替甲醇做為產製生質柴油所需之醇類，所產製之痲瘋油生質柴油，其動黏度較高皆無法達到CNS 15072之標準(3.5-5.0 mm2/s)，若需達到此標準則可考慮摻配其他低KV之柴油使用。

關鍵字

痲瘋樹籽油 ； 酯化反應 ； 轉酯化反應 ； 生質柴油 ； 異丙醇 ； 超音波

並列摘要

The study is divided into two parts. The first part examined the acid catalyzed esterification of Jatropha oil (JO) using isopropanol (IPA) via the ultrasonic irradiation (UI) assisted process. The acid value (AV), density (ρLO), kinematic viscosity (KV), yield of biodiesel(YF), isopropyl alcohol recovery and the impact of energy consumption were used to evaluate the effects of reaction temperature (T) and the alcohol/oil molar ratio (M/O) on the esterification. The results of esterification were referred to set the proper conditions to produce biodiesel of second part study, investigating the base(KOH) catalyzed transesterification. In the transesterification process, the effects of T, M/O and reaction time (t) on the biodiesel characteristics study. This combined esterification and transesterification is called two-stage biodiesel manufacture process.
The UI esterification results showed that increased M/O can significantly reduce the acid value of the oil, M/O=5 and T=80 ℃ for example decreasing from36.4 mg-KOH/g of JO reduced to 0.4 mg-KOH/g of esterified oil. It was found that when the temperature is higher than while close to the IPA boiling point (82.3 ℃), for example at 100 and 120 ℃ all the acid value can be reduced lower than 0.2 mg-KOH/g. The biodiesel yields are 75.47 and 71.42%, respectively. To ensure the appropriation of characteristics of products, the esterification temperature was chosen at 120 ℃ to obtain crude ester for the followed transesterification.
For transesterification conditions at T= 80 ℃and t=20 min the proper M/O is 9, offering biodiesel yield YF as high as 95.87 %, with AV=0.688 mg-KOH/g, ρLO =892.5 kg/m3 and KV=9.548 mm2/s while there is no significant improvement with M/O high than 9. The results also indicated that with UI the transesterification is nearly completed in 20 min. The enchancement is minor for further extending AV, density, KV and the reaction time. The use of IPA instead of methanol in biodiesel manufacture of jatropha oil, however, the products yields with KV higher than CNS 15072 standard (3.5-5.0 mm2/s) The IPA based biodiesel may mix with other diesel with low KV to meet the requirement.

並列關鍵字

Jatropha curcas seed oil ； esterification ； biodiesel ； ultrasonic ； transesterification ； IPA

參考文獻

1. Syam, A.M., R. Yunus, T.I.M. Ghazi and T.C.S. Taw (2009). "Methanolysis of Jatropha oil in the presence of potassium hydroxide catalyst." Applied Sciences 9(17): 3161-3165.

2. Achten, W. ( 2010). "Sustainability evaluation of biodiesel from Jatropha curcas L." Heverlee, Belgie: Katholieke Universiteit Leuven, Groep Wetenschap & Technologie; 2010.

3. Achten, W. M. J., L. Verchot, Y. J. Franken, E. Mathijs, V. P. Singh, R. Aerts and B. Muys (2008). "Jatropha bio-diesel production and use." Biomass and Bioenergy 32(12): 1063-1084.

4. Singh, A. K., S. D. Ferando, and R. Hernandez (2007). "Base-Catalyzed Fast Transesterification of Soybean Oil Using Ultrasonication." Energy & Fuels 21: 1161-1164.

5. Atabani, A. E., A. S. Silitonga, I. A. Badruddin, T. M. I. Mahlia, H. H. Masjuki and S. Mekhilef (2012). "A comprehensive review on biodiesel as an alternative energy resource and its characteristics." Renewable and Sustainable Energy Reviews 16(4): 2070-2093.