高酸價油品進行兩階段反應產製生質柴油

Biodiesel production from high acid value oils by a two-step process

宋軒達(Hsuan-Ta Sung)

指導教授 ： 陳奕宏

國立臺北科技大學/工程學院/工程科技研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00794

摘要

本研究使用棕櫚污泥油(Palm sludge oil)作為料源，以高溫酯化(High temperature esterification)反應降低油品的酸價(Acid value)，並利用甘油作為反應醇類，使油品中的自由脂肪酸(Free fatty acids)反應生成甘油酯類(Glycerin esters)，並獲得最適化高溫酯化操作條件為醇酸莫爾比0.9、反應溫度250 °C、與反應壓力250 mmHg，在此條件下，反應時間90 min時，酸價可降至0.93 mg KOH/g。高溫酯化後之低酸價油品，經鹼觸媒轉酯化(Transesterification)反應，可轉化成脂肪酸甲基酯(Fatty acids methyl esters)與甘油，而最適化轉酯化操作條件為甲醇實際添加量與理論莫爾比2.5、觸媒劑量1% wcat/woil、反應溫度60 °C、機械攪拌器轉速(ω) 500 rpm、與反應時間1小時，在此條件下，脂肪酸甲基酯產率為94.43%。經轉酯化所獲得之副產物甘油，若再經由適當的純化，即可作為原料投入高溫酯化反應，形成一套循環式生產生質柴油系統，針對此循環系統之最適化原物料酸價範圍作探討，並建議原料初始酸價應在70-120 mg KOH/g較利於循環的進行。此外將棕櫚污泥油與另外三種高酸價油品，棕櫚脂肪酸蒸餾物(Palm fatty acid distillates)、黃豆酸油(Soybean acid oil)、與乳木果油(Shea olein)，分別以高溫酯化/傳統轉酯化製程與傳統酯化/傳統轉酯化製程產製生質柴油，並參考文獻中各油品之脂肪酸組成，對生質柴油的油品進行分析比較。分析結果顯示，兩製程所生產之生質柴油性質並無明顯差異，除了冷濾點(Cold filter plugging point)使用高溫酯化/傳統轉酯化製程普遍低於傳統酯化/傳統轉酯化製程約1-3 °C，而氧化穩定性(Oxidation stability)使用高溫酯化/傳統轉酯化製程較傳統酯化/傳統轉酯化製程長約4-6小時，外觀上高溫酯化/傳統轉酯化製程油品顏色普遍較傳統酯化/傳統轉酯化製程深。

關鍵字

生質柴油 ； 高溫酯化 ； 高酸價油品 ； 甘油 ； 兩階段程序

並列摘要

This research uses palm sludge oil as the raw material and reduces acid value by high temperature esterification. The free fatty acids from oil are esterified by glycerol to create the glycerides. The optimal operation conditions of high temperature esterification are the molar ratio of glycerol to free fatty acids of 9:10, the reaction temperature of 250 °C, and the reaction pressure of 250 mmHg. The acid value would be less than 0.93 mg KOH/g when the reaction time was 90 minutes. The base-catalyzed transesterification of the low acid value oil from high temperature esterification produces fatty acids methyl esters and glycerol. The optimal conditions of transesterification are the molar ratio of methanol to theoretical value of 2.5:1, the catalyst dosages of 1% wcat/woil, the reaction temperature of 60 °C, the rotating speed of 500 rpm, and reaction time for 60 minutes. The yield of fatty acids methyl ester is obtained as 94.43%. The glycerol as the byproduct in the transesterification reaction can be purified to be recovered, and then be used in the high temperature esterification as a raw material. As a result, the system of the cycling production of biodiesel can be established, and the range of original acid value of oils is suggested between 70 and 120 mg KOH/g. Furthermore, other high acid value oils including palm fatty acid distillates, soybean acid oil, and shea olein were used for the high temperature esterification followed by traditional transesterification compared with those obtained by the traditional esterification/transesterification. As a result, the biodiesel properties from those two processes show no significant difference. Nevertheless, the cold filter plugging point of biodiesels from high temperature esterification followed by traditional transesterification generally is lower than those obtained by the traditional esterification/transesterification of 1 to 3 °C. The oxidation stability of biodiesels from high temperature esterification followed by traditional transesterification is greater than those obtained by the traditional esterification/transesterification of 4 to 6 hours. However, the appearance of biodiesels obtained from high temperature esterification followed by traditional transesterification is usually darker than those obtained by traditional esterification/transesterification.

並列關鍵字

Biodiesel ； High temperature esterification ； High acid value oils ； Glycerol ； Two step process

參考文獻

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