固体酸催化高酸值花椒籽油酯化降酸反应

以甘油为碳源,通过直接炭化-磺化制备了炭基固体酸催化剂。采用傅里叶转换红外光谱(FTIR)、扫描电子显微镜(SEM)、X射线光电子能谱分析(XPS)、X射线衍射(XRD)以及Boehm滴定法等方法对催化剂进行了表征,并将其首次应用于花椒籽油的酯化降酸反应。研究了反应条件对酯化反应的影响,并通过正交试验确定了最佳工艺条件:醇油比为40∶1,催化剂用量为10.0%,反应温度为75℃,反应3.5h,花椒籽油的酸值可以由最初的73.75m KOH/g降到1.63mg KOH/g,符合后续制备生物柴油的碱催化酯交换反应要求(2mg KOH/g);并且该催化剂具有较好的重复利用性。     

地沟油生产生物柴油的工艺研究

本方法是利用固体催化剂(KOH)催化地沟油生产生物柴油的工艺,工艺过程是先预酯化以降低原料的酸价(在2 mg KOH/g以下),然后再酯化反应生产生物柴油,原料油的酸值、水分可达到碱催化合成生物柴油原料油的要求。实验表明,反应醇油比为7∶1,反应温度为58℃,催化剂添加量为1.3%,反应时间为1小时以上生物柴油收率为88%。     

高酸值废油制备生物柴油的研究

以高酸值废弃油脂为原料,以同体酸为催化剂催化酸化油的预酯化反应,KOH催化转酯化反应,较系统地研究了醇-油摩尔比、反应温度、催化剂加入量、反应时间等因素对预酯化效果的影响.其优化的操作条件为:醇-油摩尔比8∶1,反应釜温度75℃,催化剂加入量为10%,反应4 h,高酸值废油的酸值由140 mg/g可降至3.8 ms/g,达到下一步酯交换阶段不出现皂化现象的要求.经KOH催化酯交换和精馏后制得的生物柴油产品部分主要指标达到德国现行生物柴油标准DIN V51606.     

陕西花椒籽油开发生物柴油项目通过评审

由陕西省林业厅协助，西北农林科技大学、陕西科技大学共同承担的“花椒籽油转化为生物柴油的研究”项目，日前通过专家评审。参与评审的专家认为：该项目研究技术达到我国生物质柴油标准。花椒籽油“变成”生物柴油的研究成功，标志着陕西省生物质能源研究进行实质性实施阶段。     

酵母菌为原料制备生物柴油工艺研究

以酵母菌为原料,KOH为催化剂,通过单因素实验,对影响传统两步法制备生物柴油的工艺条件,包括催化剂用量、衍生试剂用量、酯化时间进行考察。利用气相色谱-质谱联用分析平台对制得的生物柴油进行定性定量分析。结果表明,最佳工艺条件为:50 mg酵母菌干粉,KOH含量0.05 mol/L,甲醇用量400μL、酯化时间为3 h。生物柴油主要成分包括肉豆蔻酸甲酯、棕榈酸甲酯、十六烯酸甲酯、硬脂酸甲酯、油酸甲酯。     

非均相催化剂两步法催化潲水油制备生物柴油

对取自餐饮的潲水油进行一系列预处理,脱去其中的胶类、色素、水分等杂质,然后用自制的固体酸、固体碱催化剂经"两步法"工艺将其转化为生物柴油。结果发现,在预酯化反应中,催化剂A用量为6%、醇油摩尔比为12∶1,反应2.5 h后,潲水油的酸值由50 mg KOH.g-1降至2 mg KOH.g-1。通过正交实验得到碱催化酯交换反应最佳条件为:反应时间2 h、反应温度100℃、催化剂B用量6%、醇油摩尔比9∶1,在此条件下转化率达96.4%。表明所制备的固体酸、固体碱催化剂能有效将潲水油转化为生物柴油。     

酵母菌为原料制备生物柴油工艺研究

以酵母菌为原料,KOH为催化剂,通过单因素实验,对影响传统两步法制备生物柴油的工艺条件,包括催化剂用量、衍生试剂用量、酯化时间进行考察。利用气相色谱-质谱联用分析平台对制得的生物柴油进行定性定量分析。结果表明,最佳工艺条件为:50 mg酵母菌干粉,KOH含量0.05 mol/L,甲醇用量400μL、酯化时间为3 h。生物柴油主要成分包括肉豆蔻酸甲酯、棕榈酸甲酯、十六烯酸甲酯、硬脂酸甲酯、油酸甲酯。     

利用废食用油制备生物柴油的研究

对利用废食用油制备生物柴油的预酯化-酯交换工艺进行了研究。结果表明,预酯化的最佳工艺条件为：乙醇用量为80 mL、催化剂浓硫酸用量为1 g、反应时间为3 h、反应温度为70℃;酯交换的最佳工艺条件为：乙醇用量为60 mL、催化剂氢氧化钾用量1 g、反应时间为40 min、反应温度为70℃。在此条件下可使50 mL废食用油的酸值由40.27 mg KOH/g降到1.52 mg KOH/g,粗生物柴油的产率可达93.71%。     

文冠果生物柴油与0号柴油混配物理化性质的研究

该文以文冠果油为原料,KOH为催化剂,利用酯交换法制备生物柴油,并测定了文冠果油的部分理化性质。在此基础上,对文冠果生物柴油与0号柴油混配物(B5、B20、B40、B60、B80、B100)的密度、运动黏度、冷滤点和闪点等理化性质进行了测定。研究结果表明:以酸值为0.640 3mg KOH/g的文冠果油为原料时,通过直接酯交换制备的文冠果生物柴油各项理化性质均符合我国国家标准。生物柴油与0号柴油混配物的性质结果表明,混配物的密度与生物柴油在混配物中的体积分数是线性相关的;可用公式lnη=φ_1lnη_1+φ_2lnη_2预测混配物的运动黏度;随着混配物中生物柴油体积分数的增加,冷滤点依次降低;当生物柴油体积分数小于50%时,闪点随着生物柴油体积分数的增加而缓慢增加,当大于50%后,闪点的增加幅度增大。     

分子筛微波辐射负载CaO催化合成生物柴油

研究微波辐射法制备固体碱催化剂CaO/NaY在合成生物柴油中的应用。结果表明,该催化剂在醇油摩尔比9∶1,催化剂质量分数3%,反应温度65℃,反应时间3 h等条件下,以精制大豆油为原料制备的生物柴油得率可达95%;而以酸值(以KOH计)为4 mg/g和含水质量分数为1.5%的油脂为原料,生物柴油得率可分别达到92.4%和84.8%。催化剂结构表征表明:微波辐射改善了CaO在载体NaY上的分散,其总碱量(H-27)达到3.798mmol/g,是一种固体超强碱。     

微酸强化超临界甲醇法连续化合成生物柴油

超临界甲醇法合成生物柴油的苛刻反应条件制约其大规模工业化。加入微量酸可提高反应速率,降低苛刻的反应条件,且不会带来后续分离问题。实验在温度270—360℃,压力9—15 MPa,停留时间300—1 300 s,醇油摩尔比(20∶1)—(40∶1)的条件下,研究了加入油酸、硬脂酸和微量磷酸对过程的强化,并进行了比较。结果表明:磷酸是最佳的酸性催化剂,在磷酸催化的条件下,最佳反应条件为温度300℃、压力13 MPa、停留时间700 s、醇油摩尔比30∶1,磷酸加入量为使大豆油酸价为15 mg/g(以每g大豆油KOH质量计)的加入量。在此条件下,脂肪酸甲酯的收率达到95%以上。     

有机碱催化制备生物柴油的条件优化

对比酸碱催化机理选用有机碱作为催化剂,研究有机碱催化制备生物柴油的条件,使反应条件温和,催化剂回收容易。通过对反应时间、温度、压力等条件考察酯交换反应及水解反应,可得到生物柴油脂肪酸甲酯含量达到96%,酸值为0.8～0.9 mg KOH/g。     

Study of variables affecting the synthesis of biodiesel from Madhuca Indica oil

Biodiesel derived from non‐edible Madhuca Indica oil (MIO) seems to be a better alternative to diesel oil in India. In the present work, effects of reaction variables such as mass ratio of methanol to oil, catalyst concentration, reaction time and reaction temperature on biodiesel yield were studied. The acid value of the commercially available MIO is high, and hence a two‐step process was used to produce biodiesel from MIO. In the first step, the acid value of the MIO was reduced to less than 1 mg KOH/g, using acid‐catalyzed transesterification. In the second step, the pretreated MIO was converted to biodiesel using alkaline‐catalyzed transesterification. From the experimental results, it is observed that the optimized conditions for biodiesel production are a 1 : 4 mass ratio of methanol to oil, 55 °C reaction temperature, 120 min of reaction time, and 1% sodium hydroxide catalyst. The properties of the MIO biodiesel were found to be within the biodiesel limits of the European Union. Hence, the MIO biodiesel can be used as a substitute for diesel for the sustainable development of rural areas and as a renewable fuel.     

An ideal feedstock, kusum (Schleichera triguga) for preparation of biodiesel: Optimization of parameters

Kusum (Schleichera triguga), a non-edible oil bearing plant has been used as an ideal feedstock for biodiesel development in the present study. Various physical and chemical parameters of the raw oil and the fatty acid methyl esters derived have been tested to confirm its suitability as a biodiesel fuel. The fatty acid component of the oil was tested by gas chromatography. The acid value of the oil was determined by titration and was found to 21.30 mg KOH/g which required two step transesterification. Acid value was brought down by esterification using sulfuric acid (H₂SO₄) as a catalyst. Thereafter, alkaline transesterification was carried out using potassium hydroxide (KOH) as catalyst for conversion of kusum oil to its methyl esters. Various parameters such as molar ratio, amount of catalyst and reaction time were optimized and a high yield (95%) of biodiesel was achieved. The high conversion of the feedstock into esters was confirmed by analysis of the product on gas chromatograph-mass spectrometer (GC-MS). Viscosity and acid value of the product biodiesel were determined and found to be within the limits of ASTM D 6751 specifications. Elemental analysis of biodiesel showed presence of carbon, hydrogen, oxygen and absence of nitrogen and sulfur after purification. Molar ratio of methanol to oil was optimized and found to be 10:1 for acid esterification, and 8:1 for alkaline transesterification. The amounts of H₂SO₄ and KOH, 1% (v/v) and 0.7% (w/w), respectively, were found to be optimum for the reactions. The time duration of 1 h for acid esterification followed by another 1 h for alkaline transesterification at 50 ± 0.5 °C was optimum for synthesis of biodiesel.     

两步法催化高酸价微藻油脂制备生物柴油

研究了两步法催化高酸价微藻油脂制备生物柴油的工艺条件。测定从产油栅藻培养物中提取的油脂的化学成分,发现油脂的游离脂肪酸含量分布在10%~32%,极性脂含量分布在21%~46%。以此高酸价、高极性脂含量油脂,经过酸预酯化-碱催化转酯化两步法制备生物柴油。其最优反应条件为:30%的醇加入量,1%油质量的硫酸催化反应2 h,其油脂酸价可从初始酸值的17~46 mg/g降低至2 mg/g以下;随后,在醇油物质的量之比为12:1,催化剂氢氧化钾用量为油质量的2%,65℃条件下反应30min,制备所得生物柴油中脂肪酸甲酯的质量分数可达96.6%,甘油三酯的转化效率接近100%。根据《柴油机燃料调合用生物柴油》国家标准,测定了微藻生物柴油产品的品质指标,发现其密度、运动黏度、酸价、氧化安定性等各项指标均符合国家标准(GB/T 20828-2007);热值为39.76 MJ/kg,符合欧盟生物柴油标准(EN 14214)。     

Synthesis of economically viable biodiesel from waste frying oils (WFO)

In present communication, waste frying oil (WFO) has been used as a feedstock for biodiesel synthesis. WFO, procured from a local Indian restaurant possessed an acid value of 0.84 mg KOH/g, which is low enough for single step transesterification reaction. Biodiesel (fatty acid methyl esters) was washed after transesterification reaction and the yield got lowered substantially (from 96% to 86.36%) after water washing owing to loss of esters. 30:100 vol% (methanol to oil), 0.6 wt% NaOCH₃, 60°C temperature and 600 rpm agitation in 1 h reaction time was found to be optimum for transesterification reaction. ¹H NMR spectrum showed a high conversion (95.19%) of fatty acids in WFO to biodiesel in 2 h reaction time. Almost complete conversion (99.68%) was attained in 2 h reaction time. © 2011 Canadian Society for Chemical Engineering     

Two approaches in preparation for cogeneration α‐tocopherol and biodiesel from cottonseed

A two‐step process and a direct alkaline transesterification process in preparation for cogeneration α‐tocopherol and biodiesel (fatty acid methyl esters, FAME) from cottonseeds were studied in this article. The effects of some factors on recovery of α‐tocopherol and conversion of cottonseed oil (triacylglycerols, TAGs) to biodiesel in the two processes were systematically studied by single factor experiments and orthogonal design method. In the two‐step process, α‐tocopherol and biodiesel were produced from extraction with two‐phase solvent followed by base‐catalysed transesterification. Approximately 95.5% TAGs was converted into biodiesel, and 1.008 mg/g (wet basis) α‐tocopherol was detected on the condition: 1:3 petroleum ether/methanol volume rate, 40°C extraction temperature; 7:1 methanol/cottonseed oil molar ratio, 1.1% KOH (w/v) concentration in methanol and 60°C esterification temperature. And in the direct alkaline transesterification reaction, 98.3% conversion of TAGs and 0.986 mg/g content of α‐tocopherol could be achieved at 60°C in 2 h. Both of the two processes were feasible from the economic point of view for further utilisation of cottonseed. © 2011 Canadian Society for Chemical Engineering     

Low boiling point organic amine-catalyzed transesterification of cottonseed oil to biodiesel with trace amount of KOH as co-catalyst

The effect of addition of trace amount of KOH as co-catalyst on low boiling point organic amine-catalyzed transesterification for biodiesel production was investigated. Three different organic amines, tri-ethylamine, di-ethylamine and tert-butylamine, were used as catalysts, and the maximum amount of KOH that could be added to these organic amine-catalyzed systems was 367.1 mg/kg oil. Under such circumstance, KOH could be left in the resultant biodiesel and no washing was needed to remove it as the concentration of K⁺ in the biodiesel met EN 14214 standards. Addition of trace amount of co-catalyst KOH with an amount of 367.1 mg/kg oil resulted in the organic amine-catalyzed transesterification under milder reaction conditions than those without addition of KOH to achieve >90% yield of methyl ester. Furthermore, side reactions that occurred in the pure organic amine-catalyzed systems could not be detected after addition of trace amount of KOH, as evidenced by the NMR results.     

Use of Phagotrophic Microalga Ochromonas danica to Pretreat Waste Cooking Oil for Biodiesel Production

In this study, the feasibility of pretreatment and/or upgrading of waste cooking oil (WCO) using the microalga Ochromonas danica was investigated. Two WCO samples with initial acid values (AV) of 10.7 mg KOH/g (~5.4 % FFA content) and 3.9 mg KOH/g (~2.0 % FFA content) were examined. The algal cells engulfed oil droplets and grew rapidly on both WCO samples. The cell growth rates on WCO were compared with the rates on olive oil, with or without surfactant addition to make the oil droplets smaller and easier for algal ingestion. Comparison was also made with the growth rate in a sugar‐based medium. More importantly, contacting the WCO with the phagotrophic O. danica cells was found to decrease the acid values of the remaining oil by 2.8 and 2.4 mg KOH/g WCO, respectively. The O. danica‐pretreated WCO, with lower acid values, are potentially better feedstock for biodiesel production.