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10MPa,反应时间6min,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%.     

棕榈油碱催化制备生物柴油实验研究

用氢氧化钾作催化剂,考察了反应温度、催化剂用量、醇油摩尔比、反应时间对棕榈油和甲醇制备生物柴油产率的影响。结果表明,最佳反应条件为:反应温度40℃,催化剂用量0.6%,醇油摩尔比6∶1,反应时间2.0 h。此时,生物柴油产率可达97.82%。     

棕榈油碱催化制备生物柴油实验研究

用氢氧化钾作催化剂,考察了反应温度、催化剂用量、醇油摩尔比、反应时间对棕榈油和甲醇制备生物柴油产率的影响。结果表明,最佳反应条件为:反应温度40℃,催化剂用量0.6%,醇油摩尔比6∶1,反应时间2.0 h。此时,生物柴油产率可达97.82%。     

超临界甲醇制备生物柴油的研究

以菜籽油为原料,在超临界甲醇中制备了生物柴油,采用正交实验考察了反应温度、醇油摩尔比和反应时间对生物柴油收率的影响.结果表明,各因素对生物柴油收率影响的显著性顺序为:反应温度》醇油摩尔比》反应时间;最佳工艺条件为:反应温度300℃、醇油摩尔比42∶1、反应时间20 min,在此条件下生物柴油的收率达到97.95%.     

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。     

耦合闪蒸的连续超临界甲醇法制备生物柴油

在耦合闪蒸装置的管式反应器中,以菜籽酸化油为原料,采用超临界甲醇法连续制备生物柴油,同时绝热闪蒸回收甲醇,考察了醇油摩尔比、反应温度、反应压力、反应时间以及闪蒸压力对生物柴油收率、甲醇回收率及气相中甲醇含量的影响。结果显示,在醇油摩尔比35∶1,反应温度300℃,反应压力13 MPa,反应时间600 s的最优条件下,生物柴油收率可达83.1%(以菜籽酸化油质量计);在最优条件及闪蒸压力为常压条件下,闪蒸甲醇回收率可达90.5%,气相中甲醇含量达97.7%;对闪蒸回收的甲醇循环使用5次后,甲醇回收率为86.8%,回收甲醇中甲醇的质量分数为93.7%,该组成的回收甲醇对生物柴油收率无明显影响。     

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%.     

盐地碱蓬油制备生物柴油工艺条件研究

以盐地碱蓬油为原料制备生物柴油.通过正交实验研究了反应温度、催化剂用量、醇油摩尔比、反应时间、搅拌强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:搅拌强度>反应时间>催化剂用量>醇油摩尔比>反应温度.盐地碱蓬油制备生物柴油的最佳工艺参数为:搅拌强度为1 800 r/min,反应时间60min,催化剂KOH用量为盐地碱蓬油质量的1%,醇油摩尔比6/1,反应温度65℃.在该工艺条件下,生物柴油产率达到97.03%.     

蓖麻油质生物柴油的制备工艺研究

研究了蓖麻油在KOH的催化下与甲醇发生酯交换反应来制备生物柴油的研究。通过醇油比、反应时间、温度和催化剂用量等进行了单因素实验及正交实验的研究;结果表明蓖麻油制备生物柴油的最佳工艺为:醇油摩尔比为7∶1,催化剂用量为蓖麻油重的0. 8%,温度为35℃,时间为2 h,在此实验条件下最佳的产率为93. 74%。通过极差分析,影响蓖麻油质生物柴油合成的主要因素为反应时间和反应温度,醇油摩尔比的影响最小。     

复合固体酸催化餐饮废油合成生物柴油的研究

通过酯转换反应生成脂肪酸甲酯即生物柴油的研究,考察了催化剂混合摩尔比、催化剂用量、醇油摩尔比、反应温度、反应时间等因素对生物柴油产率的影响;采用甘油铜比色法测定甘油含量来反映生物柴油的产率;采用红外光谱测试技术对酯交换产物进行分析.     

Preparation of biodiesel from soybean oil using supercritical methanol and co-solvent

Transesterification of soybean oil in supercritical methanol has been carried out in the absence of catalyst. A co-solvent was added to the reaction mixture in order to decrease the operating temperature, pressure and molar ratio of alcohol to vegetable oil. With propane as co-solvent in the reaction system, there was a significant decrease in the severity of the conditions required for supercritical reaction, which makes the production of biodiesel using supercritical methanol viable as an industrial process. A high yield of methyl esters (biodiesel) was observed and the production process is environmentally friendly. Furthermore the co-solvent can be reused after suitable pretreatment.     

Noncatalytic Biodiesel Fuel Production from Croton megalocarpus Oil

Biodiesel is currently considered as the most promising substitute for diesel fuel because of its similar properties to diesel. This study presents the use of the supercritical methanol method in the production of biodiesel from Croton megalocarpus oil. The reaction parameters such as methanol‐to‐oil ratio, reaction temperature and reaction time were varied to obtain the optimal reaction conditions by design of experiment, specifically, response surface methodology based on three‐variable central composite design with α = 2. It has been shown that it is possible to achieve methyl ester yields as high as 74.91 % with reaction conditions such as 50:1 methanol‐to‐oil molar ratio, 330 °C reaction temperature and a reaction period of 20 min. However, Croton‐based biodiesel did not sustain higher temperatures due to decomposition of polyunsaturated methyl linoleate, which is dominant in biodiesel. Lower yields were observed when higher temperatures were used during the optimization process. The supercritical methanol method showed competitive biodiesel yields when compared with catalytic methods.     

叔戊醇体系酶促大豆油制备生物柴油

叔戊醇作为反应介质,固定化脂肪酶Novozym 435催化大豆油与甲醇的转酯反应制备生物柴油。叔戊醇消除了反应底物甲醇及反应副产物甘油对酶活的负面影响。定量分析表明,叔戊醇与油脂的体积比为1,甲醇与油脂的摩尔比为3,2%脂肪酶,反应体系含水量2%,40 ℃、180 r/min条件下反应15 h,生物柴油得率可达97%。在最适条件下反应进行160批次,酶仍保持了较高的活性和良好的稳定性。     

Use of supercritical methanol/carbon dioxide mixtures for biodiesel production

The use of supercritical conditions for the production of biodiesel from both vegetables oils and waste-oils may be of great industrial interest because it can be carried out without those catalysts necessary in the conventional transesterification process, therefore avoiding a complex separation between the product and the catalyst. However, the use of supercritical alcohol requires higher operating temperatures and pressures. In this work, CO₂ was added to the reaction mixture in order to reduce the operating conditions (temperature, pressure and molar ratio of alcohol to vegetable oil). The novelty of using CO₂ may have two advantages: a possible combination of supercritical CO₂ extraction of the oil and its subsequent transesterification reaction without CO₂ depressurization, and a reduction of the supercritical temperature and pressure of the mixture. The effects of temperature (280-350 °C), pressure (140-280 bar), methanol-to-oil molar ratio (20-30), CO₂-to-methanol molar ratio (0.05-0.2) and residence time (0-45minutes) on the yield of methyl esters (biodiesel) were studied in a batch reactor, obtaining in all cases a relatively low increase in the yield when CO₂ was present in the medium. The yields of biodiesel were tested with three vegetable oils used as model compounds (palm, sunflower and borage), obtaining similar results.     

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%。     

Biodiesel synthesis from waste vegetable oil via transesterification reaction in supercritical methanol

Response surface methodology (RSM) was applied to analyze the effect of four independent variables (molar ratio of methanol to oil, reaction temperature, pressure and time) on the yield of the biodiesel production via supercritical methanol (SCM) method. Waste vegetable oil (WVO) was used as raw material and transesterification reaction was performed in a supercritical batch reactor. The central composite rotatable design was used to maximize the yield of the biodiesel. The optimal values of variables were determined by RSM to be 33.8:1 (methanol/oil molar ratio) 271.1 °C, 23.1 MPa and 20.4 min reaction time for the maximum predicted yield of 95.27% (g/g). Moreover, an irreversible first order kinetic model was successfully correlated to the experimental transesterification data with 3.37 (s⁻¹) and 31.71 (kJ/mol) as the frequency factor and activation energy of the process.     

Variables Affecting the Production of Standard Biodiesel

Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. The oils must be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and European biodiesel standards. It is also believed that sodium hydroxide can never be used as the catalyst because it causes soap formation, which either lowers the yield or raises the acid number and makes product isolation difficult. Methods for producing standard biodiesel from low-acid-number soybean oil, in one chemical reaction using sodium hydroxide and a cosolvent, were recently reported. This study reports the effects of variables on the acid numbers and chemically bound glycerol contents of the products which led to the methods. These variables were the molar ratio of alcohol to oil, catalyst concentration, cosolvent volume, and reaction time. The alcohol-to-oil molar ratio must be at least 14, and the sodium hydroxide concentration should be at least 1.2 wt% (based on oil), to meet the necessary acid number and glycerol contents of the biodiesel. The volume of tetrahydrofuran cosolvent used must be 90–130% of that required to just create complete miscibility at the beginning of the reactions.     

Phase diagrams for vegetable oil/methanol mixtures

Based on the analysis of literature data, a number of vegetable oils most promising for biodiesel synthesis were selected. The studies of the phase state and calculations of the phase diagrams for methanol/oil were performed in a wide range of temperature, pressure and alcohol/oil molar ratios. The conditions to provide supercritical state of the reaction mixture at vegetable oil conversion were found.     

Biodiesel production using supercritical methanol/carbon dioxide mixtures in a continuous reactor

Fatty acid methyl esters (biodiesel) were produced by the transesterification of triglycerides with compressed methanol (critical point at 240 °C and 81 bar) in the presence of solid acids as heterogeneous catalyst (SAC-13). Addition of a co-solvent, supercritical carbon dioxide (critical point at 31 °C and 73 bar), increased the rate of the supercritical alcohols transesterification, making it possible to obtain high biodiesel yields at mild temperature conditions. Experiments were carried out in a fixed bed reactor, and reactions were studied at 150-205 °C, mass flow rate 6-24 ml/min at a pressure of 250 bar. The molar ratio of methanol to oil, and catalyst amount were kept constant (9 g). The reaction temperature and space time were investigated to determine the best way for producing biodiesel. The results obtained show that the observed reaction rate is 20 time faster than conventional biodiesel production processes. The temperature of 200 °C with a reaction time of 2 min were found to be optimal for the maximum (88%) conversion to methyl ester and the free glycerol content was found below the specification limits.     

响应面法优化碱催化酯交换反应制备生物柴油工艺研究

根据中心组合试验设计原理，通过30个试验，其中有6个样本的中心点，以甲酯含量作为响应值。考察反应时间、催化剂用量、反应温度和醇油摩尔比对碱催化酯交换反应的影响，确定碱催化酯交换反应制备生物柴油的二阶多项式模型。试验结果很好地拟合模型及对99％以上的差异做了解释，优化工艺参数的反应时间为45min、催化剂用量为1．5％、反应温度50℃、醇油摩尔比为7．5，试验值在95％的置信区间符合预测值。结果表明，RSM优化的模型适合于碱催化酯交换反应制备生物柴油工艺，能够预测不同条件下碱催化酯交换反应得到甲酯含量。