酶催化餐饮业废油脂生产生物柴油的研究

研究了利用餐饮业废油脂和甲醇,在无溶剂系统中通过脂肪酶的转酯作用来生产生物柴油.结果表明,醇油摩尔比为3∶1时甲醇转化率只能达到48%左右,醇油摩尔比低于1∶1时甲醇转化率能达到95%以上,采用分批添加法,甲醇总转化率可以明显提高到80%以上.反应体系的最适初始水活度应控制在0.54～0.75之间,随着反应温度的升高,酯交换反应的速度加快,但酶失活率也随之增大.     

利用大豆毛油合成生物柴油技术研究

研究了利用大豆毛油与甲醇在超临界条件下制备生物柴油的工艺条件,考查了反应温度、压力、醇油摩尔比和反应时间对大豆毛油与甲醇进行酯交换反应转化率的影响,并得到最优反应条件:温度320℃,压力10MPa,醇油摩尔比10∶1,反应时间60min。     

负载型固体碱催化合成甲酯生物柴油的研究

采用浸渍法制备了Na2CO3/高岭土负载型固体碱催化剂,用于催化大豆油与甲醇酯交换反应制备甲酯生物柴油。考察了反应时间、催化剂用量、反应温度和醇油摩尔比对酯交换反应转化率的影响,并通过单因素试验确定了最优工艺条件。结果表明:反应时间4 h、反应温度60℃、催化剂用量3%和醇油摩尔比12∶1条件下,酯交换反应转化率达到90.5%。     

连续化条件下超临界甲醇法制备生物柴油

在连续操作的管式反应器中,以大豆油为原料在压力11～19MPa,温度240～400℃的超临界甲醇条件下进行连续化制备生物柴油的研究。考察了在连续反应条件下醇油摩尔比、压力、温度、停留时间及共溶剂对大豆油转化率的影响。实验结果表明:较高的醇油摩尔比有利于油脂转化率的提高,但当醇油摩尔比超过40:1后提高醇油摩尔比对提高油脂转化率的影响不大;在11～15MPa范围内,压力升高对油脂转化率影响很大,但高于15MPa后压力对转化率的影响减弱;反应温度对油脂转化率有着重要影响,在300℃以上随着温度的升高,油脂转化率有较大幅度的上升,但温度太高油脂会发生分解反应;醇油摩尔比40:1,温度350℃,压力15MPa,停留时间1000s是该实验获得的最佳反应条件,在该条件下油脂转化率可达89%。实验还研究了添加共溶剂四氢呋喃对油脂转化率的影响。     

分子筛型固体碱催化剂用于酯交换反应制备生物柴油

采用等体积浸渍法制备了NaOH/NaX固体碱催化剂,用于催化大豆油与甲醇酯交换反应制备甲酯生物柴油。考察了NaOH负载量、焙烧温度、反应时间、反应温度、催化剂用量和醇油摩尔比对转化率的影响。结果表明,在NaOH负载量25%,焙烧温度500℃,反应时间4 h,反应温度65℃,催化剂用量3%和醇油摩尔比12条件下,转化率达95.3%。     

酸催化制备生物柴油的研究

采用硫酸作催化剂,利用高酸值油脂与甲醇的酯交换反应,制备生物柴油。为了提高收率,采用了两次酯交换反应;考察了醇油摩尔比、催化剂用量、反应温度等因素对收率的影响。结果表明,当醇与油的摩尔比为1∶10,催化剂用量0.5%,反应时间2.0 h,反应温度150℃,压力0.4~0.6 MPa时,生物柴油的收率可达98%。     

碱催化法制备生物柴油工艺研究

在250m l间歇式高压反应器中,以大豆油为原料,研究KOH催化甲醇酯交换反应制备生物柴油的工艺条件。主要考察了醇油摩尔比、反应温度、反应时间、催化剂用量等操作条件对脂肪酸甲酯转化率的影响。结果表明,当KOH用量为1%(wt),醇油摩尔比为5∶1,反应温度为65℃时,反应时间为15m in,脂肪酸甲酯的转化率可以达到92%。     

硅钨酸在麻疯树油合成生物柴油中的应用研究

以麻疯树油与甲醇为原料,以硅钨酸为催化剂,通过酯交换反应制备生物柴油。考察了不同反应温度、反应时间、醇油摩尔比、催化剂质量分数等因素对生物柴油转化率的影响,并采用FT-IR和1H-NMR分别对催化剂进行了表征。研究结果表明：脱水后的硅钨酸具有较强的催化活性,其在反应温度为65℃、反应时间为3 h、醇油摩尔比为12∶1、催化剂质量分数为3.0%时,麻疯树油转化成生物柴油的转化率可达81.7%。     

均相法制备生物柴油的研究

研究了添加四氢呋喃(THF)为共溶剂酸催化一步法酯交换制备生物柴油的实验过程,考察了醇油比、THF的添加量、原料中水及游离酸含量对反应的影响.结果表明,随着醇油摩尔比或THF的加量增大,转化率、收率均增大,酸价降低,最佳醇油摩尔比为21:1,最佳THF的添加质量分数为35%;原料中的水含量对于酯交换反应的副作用较大,随着水含量的增大,转化率明显降低、酸价升高,水质量分数达到1.6%以后转化率低于90%;原料中游离酸含量对反应过程影响较小,游离酸含量增大,转化率和酸价均略有增大.     

碱催化法菜籽油制备生物柴油实验研究

研究了在高压釜中碱催化作用下制备生物柴油的最优工艺条件,考察了条件因素对反应的影响,讨论了在最佳条件下甲醇中的含水量对酯交换转化率的影响.实验结果表明,催化剂用量为菜籽油质量的1.0%,醇油摩尔比为71,反应温度为50℃,反应时间为100min为优化反应条件,甲醇的含水量与转化率呈线性关系,含水量越高,酯转化率越低.     

Transesterification of the crude Jatropha curcas L. oil catalyzed by micro‐NaOH in supercritical and subcritical methanol

Transesterification of the crude Jatropha curcas L. oil catalyzed by micro‐NaOH in supercritical/subcritical methanol was studied. The effects of various reaction variables such as the catalyst content, reaction temperature, reaction pressure and the molar ratio of methanol to oil on the conversion of crude Jatropha curcas L. oil to biodiesel were investigated. The results showed that even micro‐NaOH could noticeably improve this reaction. When NaOH was added from 0.2 to 0.5 to 0.8 wt‐‰ of triacylglycerols, the transesterification rate increased sharply; when the catalyst content was further increased, the reaction rate was just poorly improved. It was observed that increasing the reaction temperature had a favorable influence on the methyl ester yield. For the molar ratio ranging from 18 to 36, the higher the molar ratio of methanol to oil was charged, the faster the transesterification rate seemed. At the fixed stirring rate of 400 rpm, when the catalyst content, reaction temperature, reaction pressure and the molar ratio of methanol to oil were developed at 0.8 wt‐‰ NaOH, 523 K, 7.0 MPa and 24 : 1, respectively, the methyl ester yield could reach 90.5% within 28 min. Further, the kinetics of this reaction was involved and the results showed that it was a pseudo‐first‐order reaction whose apparent activation energy was 84.1 kJ/mol, and the pre‐exponential factor was 2.21×10⁵.     

三油酸甘油酯与甲醇酯交换反应热力学分析

为了揭示酯交换反应的热力学特性,并为动力学研究和生物柴油的工业化生产提供基础数据,采用Benson基团贡献法和其他经验公式计算了三油酸甘油酯与甲醇之间发生的3步连续可逆酯交换反应的焓变、Gibbs自由能变及平衡常数的值,以及在303—338K各值随温度的变化关系。结果表明,在该温度范围内,反应焓接近于0,Gibbs自由能为正值,平衡常数接近于1。说明三油酸甘油酯与甲醇酯交换反应体系的反应热较小,温度对平衡的影响不大。     

海滨锦葵油超临界法制备生物柴油工艺优化

以海滨锦葵油为原料,利用超临界法制备脂肪酸甲酯(生物柴油). 通过单因素实验及正交实验研究了醇/油摩尔比、反应压力、搅拌强度、反应时间、反应温度、水分和酸值等因素对酯交换率的影响. 结果表明,在实验范围内各影响因素对酯交换率的影响依次为：反应温度>反应压力>反应时间>搅拌强度>醇/油摩尔比. 海滨锦葵油超临界法制备生物柴油的最佳工艺条件为：反应温度300℃,反应压力12 MPa,反应时间9 min,搅拌强度300 r/min,醇/油摩尔比30. 在此条件下,酯交换反应3次,酯交换率可达97.62%.     

Single‐step ultrasonic synthesis of biodiesel from crude Jatropha curcas oil

A novel single‐step process with chlorosulfonic acid catalyst for ultrasonic biodiesel synthesis using feedstock with high free fatty acid content is investigated.Jatropha curcas oil has been used as the model feedstock with methanol as alcohol. The distinct merit of chlorosulfonic acid is that it catalyzes both esterification and transesterification reactions. Moreover, chlorosulfonic acid also counteracts inhibition caused by water formed during esterification, which is the cause for very slow kinetics of acid catalyzed transesterification. In addition, sonication of the reaction mixture also causes strong micromixing and emulsification that enhances the transesterification kinetics. Statistical optimization of the process shows 93% yield for 8.5 wt % catalyst, 20:1 alcohol to oil molar ratio and temperature of 333 K. Peculiar feature of this process is that high yield is seen at moderate temperature and molar ratio, which are much smaller than that for conventional sulfuric acid catalyzed processes. The activation energy for the process (57 kJ/mol) is at least 3× lower than the energy for sulfuric acid catalyzed transesterification. The thermodynamic analysis reveals that the net Gibbs energy change for the single‐step process is almost same as that for sulfuric acid catalyzed process. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1572–1581, 2014     

Ultrasonic mixing and closed microwave irradiation-assisted transesterification of soybean oil

The present study employed ultrasonic mixing and closed microwave irradiation to assist transesterification of soybean oil. The purpose was to obtain the optimal ultrasonic mixing and closed microwave irradiation procedure. The optimal reaction conditions including amount of catalyst used, reaction temperature and methanol/oil molar ratio were also investigated to achieve the highest possible conversion rate of biodiesel. Results showed that the optimal procedure involved 1-min ultrasonic mixing and 2-min closed microwave irradiation. The optimal reaction conditions that can reach 97.7% of conversion rate were amount of catalyst used, 1.0 wt%; reaction temperature, 333 K; and methanol/oil molar ratio, 6:1.     

Transesterification of soybean oil with nano-MgO or not in supercritical and subcritical methanol

Nano-MgO can apparently improve the transesterification reaction of soybean oil with supercritical/subcritical methanol. The variables affecting the yield of methyl ester during the transesterification reaction, such as the catalyst content, reaction temperature and the molar ratio of methanol to soybean oil were investigated and compared with those of non-catalyst. When nano-MgO was added from 0.5 wt% to 3 wt%, the transesterification rate increased evidently, while the catalyst content was further enhanced to 5 wt%, little increased in yield. It was observed that increasing the reaction temperature had a favorable influence on methyl ester yield. In addition, for molar ratios of methanol to soybean oil ranging from 6 to 36, the higher molar ratios of methanol to oil was charged, the faster transesterification rate was obtained. When the temperature was increased to 533 K, the transesterification reaction was essentially completed within 10 min with 3 wt% nano-MgO and the methanol/oil molar rate 36:1. Such high reaction rate with nano-MgO was mainly owing to the lower activation energy (75.94 kJ/mol) and the higher stirring.     

SO3H-功能化季铵盐离子液体催化酯交换制备生物柴油

采用两步合成法制备了4种SO3H-功能化季铵盐离子液体,红外与核磁共振光谱表征结果表明,其结构符合理论结构特点. 热稳定性分析表明,其分解温度都在200℃以上,均可作为制备生物柴油的催化剂. 将这4种离子液体用于催化制备生物柴油,其催化活性主要与其阴离子的结构有关,[n-But3N(CH2)3SO3H][CH3SO3]的催化活性最好. 甲醇:三油酸甘油酯摩尔比为12:1、催化剂用量7%(w)、在65℃下反应24 h时,油酸甲酯产率最高(89.65%). 催化剂重复使用性能良好.     

Transesterification of rapeseed oil in subcritical methanol conditions

In this study, transesterification of rapeseed oil using subcritical methanol conditions was studied. The objective of the work was characterizing the methyl esters for its use as biodiesel in compression ignition motors. The variables affecting the methyl ester yield during the transesterification reaction, such as, the catalyst type and content, reaction temperature and pressure, the presence of hexane as co-solvent, the methanol oil molar ratio and the methanol hexane molar ratio were investigated to optimize the reaction conditions. The evolution of the process was followed by gas chromatography, determining the concentration of the methyl esters at different reaction times. The biodiesel was characterized by its density, viscosity, saponification value, iodine value, acidity index and water content, according to ISO norms. High methyl ester yield and fast reaction rate could be obtained even if the reaction pressure was relatively low, which is quite favorable to the production of biodiesel in industry.     

酸性离子液体［(CH2)4SO3HMIM］［HSO4］催化潲水油制备生物柴油的研究

制备了酸性离子液体[(CH₂)₄SO₃HMIM］［HSO₄］并用于催化潲水油制备生物柴油,研究了反应时间、反应温度、醇油物质的量比和剂油物质的量比等对酯交换反应转化率的影响,确定了较适宜的反应条件。结果表明,在反应时间4 h、反应温度140 ℃、醇油物质的量比12和剂油物质的量比0.08条件下,酯交换反应转化率为92.13%。制备的生物柴油达到了中国柴油机燃料调合用生物柴油(BD100)标准GB/T20828-2007。