Production of Biodiesel with Seed Soybean and Supercritical Ethanol

This paper presents a study of biodiesel production by a non-catalytical process. The innovation in this study is the use of novel materials for production: seed soybean (Glycine Max) “in natura” and ethanol in a supercritical state. To conduct the experiments, a bench reactor with a capacity of 150 mL, resistant to pressure of up to 300 bar and temperature of 350°C was developed. The fractional factorial experimental design () was used to evaluate the temperature, seed granulometry, molar ratio ethanol/oil and water percent of the mixture. The best yield observed was that of 94.07%, 10 minutes after the reactor entered a supercritical condition. Significant effects on seed granulometry, molar ratio ethanol, oil and temperature were verified. From the proposed process, biodiesel and toasted soybean seed were obtained. To purify the biodiesel sample it was necessary to use ultra-centrifugation to separate seed particles, and rotoevaporation to separate the fatty acid ethyl ester and unreacted ethanol. The chemical analyses were conducted directly by gas chromatography. The yield was calculated in accordance with concentrations obtained in the chromatographic analysis and seed mass of the experiment. Also checked was the presence of palmitate esters, stearate, oleate, linoleate and linolenate. By analyzing the ester composition it was possible to assess whether a good quality biodiesel was available. The roasted soybean seeds obtained after the reaction showed a calorific potential of 2203.17 kcal/kg and also be used as fuel.

Extending Functionality of Microalgae and Transesterification under Supercritical Fluid Conditions

The experimental data on supercritical CO2 extraction of microalgae are presented. It is confirmed that microalgae contains omega-3 fatty acid components. Phase equilibria data are presented for the triolein-methanol (T = 413 K, P = 5.8 - 11.9 MPa) and ethyl eicosapentaenoate-carbon dioxide (T = 313 - 333 K, P = 10 - 21 MPa) binary systems. The scheme of the batch-type experimental setup for supercritical transesterification of oils is presented. Temperature and molar ratio dependences of non-refined palm oil yield to fatty acid methyl esters (FAME) are presented for T = 563 - 693 K, methanol to palm oil molar ratio 39:1. Experiments on ultrasonic emulsification of rapeseed oil-ethanol mixture (molar ratios 150:1 - 7:1) were conducted. Research data on ultrasonic emulsion stability are presented for the time range of 0 - 40 minutes after ultrasonication completion. Correlation is defined between FAME yield of emulsified reaction mixtures and the emulsion grain size. FAME yields are compared for emulsified and non-emulsified reaction mixtures.

Influence of Fatty Acid Profiles during Supercritical Transesterification of Conventional and Non-Conventional Feedstocks: A Review

In this study, the influence of fatty acids of both conventional and non-conventional oils in supercritical transesterification method has been reviewed. Literature on oils such as moringa oleifera, manketti, croton megalocarpus, palm and soybean has been reviewed to establish an understanding of the supercritical transesterification that employed methanol as alcohol. This study reveals that lower yield of methyl esters is observed when higher temperatures are employed in oils that are highly dominated with polyunsaturated fatty acids, such as manketti and croton megalocarpus. And the reason is that poly-unsaturated fatty acids that are present in the oils decompose easily at higher temperatures and thus reduce the methyl esters yield.

Improvement of Biodiesel Product Yield during Simple Consecutive-Competitive Reactions

Biodiesel is a renewable fuel that can be made from vegetable oil and waste restaurant greases by catalysed transesterification reactions. Over 5 billion gallons of biodiesel was produced in 2010. The European Union and United States are seeing the sigmoidal portion of the growth curve in biodiesel production. Economic analysis such as profitability and annualized worth (AW) of a biodiesel plant in Taiwan is presented. With the revenue from glycerine byproduct recovery and with lower raw material costs, biodiesel may be profitable especially during days of higher gasoline prices. Multiple reactions of the consecutive-competive type may be used to model the methonolysis of trigylcerides. The reaction rate constant ratios and residence time in the reactor are important parameters in determining higher selectivity of FAME, fatty acid methyl ester product yield over glycerol by-product production. Illustrations of higher FAME yield, higher glycerol yield and cross-over from FAME to glycerol are shown for some values of reaction rate constant ratios and reaction scheme from triglycerides to diglycerides, monoglycerides and glycerol along with formation of FAME in each step by addition of methanol and catalyst is shown. Product distribution curves are presented in Figures 2-5 for different values or reaction rate constant ratios.

酯交换法制备生物柴油的研究进展

综述了酯交换制备生物柴油的方法 ,详细介绍了酯交换法中各种酯交换过程制备生物柴油的研究进展 。

生物柴油的超临界制备工艺研究

生物柴油作为一种可再生能源,可以由动植物油通过酯化反应来制备,它在燃料特性方面与矿物柴油有着十分相似的品质,能满足欧洲2号排放标准,有优良的环境特性,是一种利于环境保护的绿色燃油。探索了在超临界条件下,以甲醇和植物油为原料进行酯交换反应的制备工艺。结果表明最佳工艺条件为:甲醇与大豆油摩尔比为50:1,反应温度320℃,反应压力12-18MPa,反应时间 12-15 min。植物油可再生,甲醇可循环使用,反应无污染物排出,该工艺属于绿色化学工艺。

生物柴油制备技术的研究进展

生物柴油不仅燃烧性能与石油柴油相当,且具有环境友好、资源可再生的优点,是替代石油柴油的理想燃料之一。综述了热裂解法和酯交换法(包括化学催化法、酶催化法和超临界法)制备生物柴油的最新研究进展,并探讨了各种制备方法的优缺点和应用前景。为降低生物柴油成本,应采用廉价原料(如废油脂)。对于酸值高的废油脂,宜采用固体酸和离子液体等环境友好催化剂。

超临界甲醇中制备生物柴油

研究了超临界甲醇法制备生物柴油中反应条件对甲酯生成率的影响。结果表明,醇油摩尔比越大,大豆油转化率越高;升温有助于提高反应速率,在临界温度239℃附近,温度的影响尤其明显;当压力高于13.5 MPa时,压力对反应的影响不明显;原料油中,不同脂肪酸酯甲酯化的速率不同,按亚油酸酯、油酸酯、棕榈酸酯、硬脂酸酯的顺序依次降低;大豆油中w(游离油酸)<50%时,不影响反应转化率;原料油中w(H2O)<20%时对反应影响不大。当醇油摩尔比为42∶1,反应温度280℃,反应1 h,油脂转化率可达78%。

油菜籽与超临界甲醇原位萃取-酯交换反应制备生物柴油

以油菜籽和甲醇为原料,在甲醇的超临界状态下进行原位萃取-酯交换反应制备生物柴油,研究了产物的主要组成以及反应温度、反应压力和原料比对生物柴油产率的影响。结果表明,产物主要由亚油酸甲酯、油酸甲酯、棕榈酸甲酯、硬脂肪酸甲酯和亚麻酸甲酯构成;并发现反应温度、反应压力以及菜籽与甲醇的质量比是影响甲酯产率的主要因素,在菜籽与甲醇质量比为1∶4,反应压力和反应温度分别为14 MPa和280℃时,萃取和酯交换反应可同时在10 m in内完成,且油菜籽中所含的油脂转化率可达到94.3%。

酯交换制油酸甲酯的基团贡献法热力学分析

采用基团贡献法和赵氏经验公式(ΔSv=AslgTb+Bs)计算了三油酸甘油酯与甲醇之间发生的三步连续可逆酯交换反应的标准摩尔反应焓、标准摩尔熵、标准摩尔反应Gibbs函数和标准平衡常数,并分析了酯交换反应转化率的影响因素。结果表明,酯交换反应是放热反应,低温和高压有利于反应的进行。酯交换反应的转化率在甲醇液相时受温度和压力的影响较小,醇油比增大可以提高反应的转化率,当醇油比为20∶1时转化率达到98.8%。酯交换反应的转化率在甲醇气相时,随着压力的增大而增大,随着温度的增大而减小。通过计算结果与实验数据进行比较,表明本文提出的分析方法是可行的。

超临界甲醇法制备生物柴油

研究了超临界甲醇法制备生物柴油中温度、醇油摩尔比、反应时间和助溶剂对甲酯生成率的影响,同时研究了加入少量的KOH以降低反应的苛刻条件。在超临界甲醇反应温度350℃,醇油摩尔比为42∶1的优化反应条件下,10 min后脂肪酸甲酯的产率达到95.0%以上;300℃时加入CO2和正己烷可以提高甲基酯的转化率;在160℃的亚临界状态下、醇油摩尔比为24∶1时,加入质量分数为0.1%的KOH,20 min后脂肪酸甲酯的转化率也达到了98.5%以上。

超临界法制备生物柴油

探索了温度、甲醇和油脂摩尔比、不同碳链的醇以及水和游离脂肪酸对超临界甲醇法制备生物柴油的影响。结果表明:300℃1、5MPa、醇油摩尔比15和1 h的反应时间较为合理。同时发现,油料中所含水和游离脂肪酸对普通的酸、碱催化法有较大影响,对超临界法则没有明显影响。经过减压精馏、水洗和干燥后的生物柴油产品性能符合美国生物柴油标准。

甘油三乙酸酯超临界酯交换反应及其动力学研究

研究了在超临界条件下甘油三乙酸酯与甲醇或乙醇的酯交换反应,分别考察了超临界状态下醇油摩尔比和温度对反应的影响。实验结果表明,甲醇或乙醇与甘油三乙酸酯的摩尔比为14、反应温度为350℃、反应时间为20m in时,乙酸甲酯或乙酸乙酯的收率分别达100%和60%。对超临界状态下动力学的研究结果表明,甘油三乙酸酯与甲醇或乙醇的酯交换反应为拟一级反应,在相同的反应条件下,采用甲醇时酯交换反应速率比用乙醇时快,相应的甘油三乙酸酯的转化率也高;甘油三乙酸酯在超临界甲醇或乙醇中酯交换反应的表观活化能分别为58.7 kJ/mol和75.1 kJ/mol,甘油三乙酸酯与甲醇酯交换反应的活化能低于与乙醇酯交换反应的活化能,表明碳链短的醇更易进行酯交换反应。

超临界法制备生物柴油的研究

生物柴油的制备方法有直接混合法、微乳液法、高温裂解法和酯交换反应法。针对超临界流体技术制备生物柴油的技术,分别介绍了超临界流体中化学反应的特点,国内外对超临界法制备生物柴油的研究进展,超临界法制备生物柴油的装置及工艺,影响超临界流体制备生物柴油的因素,如温度、醇油比、游离脂肪酸和水等,超临界流体制备生物柴油的工业化应用状况;展望了超临界流体技术制备生物柴油的发展趋势。

废弃油脂超临界法制备生物柴油研究

以废弃油脂为原料,利用超临界法制备生物柴油。通过单因素实验及正交实验研究了醇油摩尔比、反应压力、催化剂用量、反应时间、反应温度等因素对生物柴油产率的影响。结果表明,在实验范围内各影响因素对生物柴油产率作用的大小依次为:反应温度>反应压力>催化剂用量>反应时间>醇油摩尔比。废弃油脂超临界法制备生物柴油的最佳工艺条件为:反应温度240℃,反应压力10 MPa,反应时间6 min,催化剂用量0.06%,醇油摩尔比40/1。在此条件下,生物柴油产率达到99.37%。

超临界条件连续操作制备生物柴油的初步研究

生物柴油是用动植物油脂或长链脂肪酸与甲醇等低碳醇合成的脂肪酸酯。是一种新兴的替代能源。对在压力9～21MPa、温度260～400℃的超临界甲醇条件下在连续化装置中制备生物柴油进行了探索性研究。讨论了不同的反应时间、温度、压力及摩尔比对大豆油转化率的影响。实验结果表明，连续操作的转化率比超临界条件下高压釜中间歇式操作低，这主要是由于甲醇与大豆油的混合状况不好引起的，井提出了在甲醇中添加有机溶剂、采用更好的混合器等改进方法。

生物柴油开发与应用

综论了国内外生物柴油的生产现状,对生物柴油的原料及不同原料的生物柴油性状进行了比较,介绍了化学酯交换、生物酶催化和超临界甲醇法等生物柴油的生产工艺,简述了生物柴油未来发展的趋势以及研究方向。

KF/MMT固体碱催化剂的制备及催化酯交换反应

采用蒙脱土(MMT)为载体,通过浸渍法制备了KF/MMT固体碱催化剂,将其应用于大豆油制备生物柴油的酯交换反应中。通过XRD、FTIR、Hammett指示剂法、N2吸附-脱附、SEM等方法对KF/MMT催化剂结构进行了表征,并考察了酯交换反应条件对生物柴油产率的影响。结果表明:负载的KF与载体蒙脱土之间存在相互作用,催化剂表面存在Al—O—K活性中心;以KF/MMT为催化剂,在催化剂用量4%,醇油摩尔比12∶1,反应温度65℃,反应时间2.5 h条件下,生物柴油产率达到97.4%。

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。