水和游离脂肪酸对DBU催化制备生物柴油的影响

以低品质油脂作为生产生物柴油的原料可以有效降低产品的成本。催化剂对原料油中主要杂质游离脂肪酸和水分的耐受程度决定了该工艺对原料油的适应性。本文采用有机碱1,8-二氮杂双环[5,4,0]十一碳-7-烯（DBU）催化酯交换反应制备生物柴油,研究了不同水和游离脂肪酸含量下酯交换反应的转化率、反应后产物两相的组成以及各组分在两相的分配。结果表明,DBU作为催化剂时,对水和游离脂肪酸具有较强的耐受性：水含量小于2%（质量分数,下同）,游离脂肪酸含量小于5%;1.5%左右的水对反应具有促进作用,水含量为1.5%时,酯交换转化率最高可达93.7%。此外,水和游离脂肪酸会降低甲醇、DBU在甲酯相中的分布,这使得甲酯相中甲酯的纯度有所上升。     

麻疯果油制备生物柴油及其经济效益

选用了非食用油麻疯果油为原料,以氢氧化钠、氢氧化钾、甲醇钠为催化荆,通过酯交换法制取生物柴油,研究表明最适宜工艺条件为:醇油比6:1,反应温度60℃,反应时间80min,搅拌强度为600 r/min,催化剂用量为1.2%,转化率达到97%以上,且生物柴油各项理化指标均符合美国和德国测试标准.且从麻疯果的种植到生物柴油的生产整个产业链出发,其原料成本更低,经济效益更大,体现了不与粮争地的优势.     

小桐子油脂肪酸聚酯多元醇及聚氨酯泡沫的制备和性能

研究了脂肪酸环氧-开环-酯化三步反应制备聚酯多元醇,比较了3种不同碘值的脂肪酸原料制备的聚酯多元醇及其聚氨酯泡沫（PUF）性能。脂肪酸碘值越高多元醇的羟值也越高：1#、2#和3#聚酯多元醇羟值分别为：261.47 mgKOH/g、370.28 mgKOH/g和434.49 mgKOH/g。3种多元醇的相对分子量为600～2000。3种泡沫的压缩和弯曲性能与泡沫密度成正比。泡沫SEM分析显示：羟值较高的多元醇泡沫2#和3#泡沫孔结构较规则,以正五边形和正六边形居多;1#泡沫泡孔不规则,易变形。对3种泡沫的TG-DSC、DTG分析结果表明：3种泡沫的热分解温度都约为300 ℃,具有较好热稳定性。     

离子液体催化麻疯树籽油制备生物柴油工艺

离子液体作为绿色液体催化剂具有优良的性能而倍受关注,然而关于离子液体催化合成生物柴油的报道很少。文中以N-甲基咪唑、吡啶为原料,合成N-(4-磺酸基)苄基吡啶硫酸氢根盐离子液体,其结构经IR,1HNMR所证实;以该离子液体为催化剂,催化麻疯树籽油合成生物柴油。在单因子实验基础上,通过正交试验法对反应温度、催化剂的用量、反应时间和醇油摩尔比等影响合成生物柴油的因素进行了优化,同时也对离子液体的稳定性进行了检验。实验结果表明:在反应温度140℃、醇油摩尔比为15∶1、反应时间6 h和催化剂用量为油质量的5%工艺条件下,生物柴油产率可达89.9%,且离子液体的稳定性好,可循环使用5次。此方法制备的生物柴油的主要质量指标与国内外生物柴油生产标准接近。     

废油脂预处理及制备生物柴油研究进展

介绍了废油脂的预处理工艺及我国废油脂的现状,重点阐述了国内外以废油脂为原料经碱法、酸法和酶法酯交换制备生物柴油的研究情况,并对目前存在的问题和相应的解决对策进行了简单的讨论。     

麻疯树籽制备生物柴油的中试研究

以100 L反应釜进行了制备麻疯树生物柴油的中试实验,并研究了反应温度、醇油比、催化剂用量、搅拌速率对转化率的影响。实验结果表明,最佳反应条件为:反应温度60℃,醇油质量比为1∶4.5,催化剂KOH用量为油重1.2%,搅拌速率150 r/min,反应60 min时转化率达到最高值98.3%。所得产品基本达到GB/T20828—2007《柴油机燃料调合用生物柴油(BD100)》所规定的技术要求,净热值达到0#柴油的90.1%。     

微量酸催化麻疯树籽油制备生物柴油(英文)

Biodiesel produced from crude Jatropha curcas L.oil with trace sulfuric acid catalyst(0.02%-0.08% oil) was investigated at 135-184 ℃.Both esterification and transesterification can be well carried out simultane-ously.Factors affecting the process were investigated,which included the reaction temperature,reaction time,the molar ratio of alcohol to oil,catalyst amount,water content,free fatty acid(FFA) and fatty acid methyl ester(FAME) content.Under the conditions at 165 ℃,0.06%(by mass) H2SO4 of the oil mass,1.6 MPa and 20:1 methanol/oil ratio,the yield of glycerol reached 84.8% in 2 hours.FFA and FAME showed positive effect on the transesterification in certain extent.The water mass content below 1.0% did not show a noticeable effect on trans-esterification.Reaction kinetics in the range of 155 ℃ to 175 ℃ was also measured.     

制备生物柴油用高游离脂肪酸花椒籽油的酯化法降酸

花椒籽油要达到制备生物柴油的要求,必须进行降酸处理。简单介绍了降酸前处理中的脱胶和脱色,甲醇酯化降酸的较优工艺为:催化剂浓硫酸浓度为2%,醇油摩尔比为30∶1,反应时间为2.5 h,反应温度为60℃。在此条件下,花椒籽油酸值可由78.91 mg KOH/g降到1.56 mg KOH/g,可以满足后期制备生物柴油要求。     

离子液体催化麻疯树果油制备生物柴油

通过两步法制备了一种酸性功能化离子液体[BSO3HMIM]HSO4,以麻疯树果油为原料,考察了离子液体[BSO3HMIM]HSO4催化下,甲醇和麻疯树果油酯交换制备生物柴油的性能。结果表明,当醇油摩尔比为12,离子液体[BSO3HMIM]HSO4用量为6%,反应时间为5h,反应温度为120℃时,生物柴油收率可达93.4%,且离子液体[BSO3HMIM]HSO4具有较好的重复使用能力,重复使用6次后,生物柴油的收率没有明显降低。     

Optimization of factors affecting esterification of mixed oil with high percentage of free fatty acid

Increased environmental awareness and depletion of resources are driving industry to develop alternative fuels from renewable sources that are environmentally more acceptable. Biodiesel is a non petroleum based fuel that consists of alkyl esters from transestrification of the refined/edible types of vegetable oils alcohol and alkaline catalysts can be used. These catalysts require anhydrous conditions and feed stocks with low levels of free fatty acids (FFAs). Inexpensive feed stocks are used in biodiesel production to reduce its cost and to get rid of waste oils in environmentally friendly way. These oils may contain high levels of FFAs so it cannot be directly used with the base catalysts currently employed. Acid esterification reduces the FFAs content to the desirable level. The major factors that affect the conversion efficiency of the process are molar ratio of alcohol/oil, amount of catalyst, reaction temperature, catalyst type and stirring speed according to reaction duration. For this study, we used a model acid produced by mixing pure oleic acid with mixed oil (50% sunflower + 50% soybean oil). Methanol was used in the experiments due to its low cost. The best conversion efficiency obtained was 96.6% for a molar ratio of 6:1 at a temperature of 60 °C, 2.5% H₂SO₄ and stirring speed of 300 rpm. Finally, different types of waste cooking oil from home and restaurants were used to study the conversion efficiency compared with optimum conditions calculated for model acid oil to be used in biodiesel production with low cost.     

Producing biodiesel from high free fatty acids waste cooking oil assisted by radio frequency heating

Efficient biodiesel conversion from waste cooking oil with high free fatty acids (FFAs) was achieved via a two-stage procedure (an acid-catalyzed esterification followed by an alkali-catalyzed transesterification) assisted by radio frequency (RF) heating. In the first stage, with only 8-min RF heating the acid number of the waste cooking oil was reduced from 68.2 to 1.64 mg KOH/g by reacting with 3.0% H₂SO₄ (w/w, based on oil) and 0.8:1 methanol (weight ratio to waste oil). Then, in the second stage, the esterification product (primarily consisting of triglycerides and fatty acid methyl esters) reacted with 0.91% NaOH (w/w, based on triglycerides) and 14.2:1 methanol (molar ratio to triglycerides) under RF heating for 5 min, and an overall conversion rate of 98.8 ± 0.1% was achieved. Response surface methodology was employed to evaluate the effects of RF heating time, H₂SO₄ dose and methanol/oil weight ratio on the acid-catalyzed esterification. A significant positive interaction between RF heating time and H₂SO₄ concentration on the esterification was observed.     

Reduction of high content of free fatty acid in sludge palm oil via acid catalyst for biodiesel production

In this study, sulphuric acid (H₂SO₄) was used in the pretreatment of sludge palm oil for biodiesel production by an esterification process, followed by the basic catalyzed transesterification process. The purpose of the pretreatment process was to reduce the free fatty acids (FFA) content from high content FFA (> 23%) of sludge palm oil (SPO) to a minimum level for biodiesel production (> 2%). An acid catalyzed esterification process was carried out to evaluate the low content of FFA in the treated SPO with the effects of other parameters such as molar ratio of methanol to SPO (6:1-14:1), temperature (40-80 °C), reaction time (30-120 min) and stirrer speed (200-800 rpm). The results showed that the FFA of SPO was reduced from 23.2% to less than 2% FFA using 0.75% wt/wt of sulphuric acid with the molar ratio of methanol to oil of 8:1 for 60 min reaction time at 60 °C. The results on the transesterification with esterified SPO showed that the yield (ester) of biodiesel was 83.72% with the process conditions of molar ratio of methanol to SPO 10:1, reaction temperature 60 °C, reaction time 60 min, stirrer speed 400 rpm and KOH 1% (wt/wt). The biodiesel produced from the SPO was favorable as compared to the EN 14214 and ASTM D 6751 standard.     

阳离子交换树脂催化酸性油脂酯化脱酸

采用阳离子交换树脂为催化剂研究了酸性油脂的酯化脱酸工艺。分别筛选了001×4,001×7,D113,HD-8,CD-552等几种型号的树脂,其中以CD-552催化效果最好。研究了反应时间、醇酸摩尔比和酸性油脂中催化剂质量分数对CD-552催化酯化脱酸效果的影响。在醇酸摩尔比30∶1,反应温度60℃,树脂质量分数5%和反应时间5 h的工艺条件下,酸性油脂经CD-552催化酯化脱酸后,酸值从10.97 mg/g降低到0.689 mg/g。反应后树脂易分离,能够循环使用,有效地解决了传统的脱酸催化剂不足,对以酸性油脂为原料的生物柴油的生产具有应用前景。     

Study on the composition of rice bran oil and its higher free fatty acids value

The compositions of rice bran oils (RBO) and three commercial vegetable oils were investigated. For refined groundnut oil, refined sunflower oil, and refined safflower oil, color values were 1.5–2.0 Lovibond units, unsaponifiable matter contents were 0.15–1.40%, tocopherol contents were 30–60 mg%, and FFA levels were 0.05–0.10%, whereas refined RBO samples showed higher values of 7.6–15.5 Lovibond units for color, 2.5–3.2% for unsaponifiable matter, 48–70 mg% for tocopherols content, and 0.14–0.55% for FFA levels. Of the four oils, only RBO contained oryzanol, ranging from 0.14 to 1.39%. Highoryzanol RBO also showed higher FFA values compared with the other vegetable oils studied. The analyses of FA and glyceride compositions showed higher palmitic, oleic, and linoleic acid contents than reported values in some cases and higher partial glycerides content in RBO than the commonly used vegetable oils. Consequently, the TG level was 79.9–92% in RBO whereas it was >95% in the other oils studied. Thus, refined RBO showed higher FFA values, variable oryzanol contents, and higher partial acylglycerol contents than commercial vegetable oils having lower FFA values and higher TG levels. The higher oryzanol levels in RBO may contribute to the higher FFA values in this oil.     

Methylation of wood fatty and resin acids for production of biodiesel

The purpose of the present paper is to evaluate the potentiality of the wood oil of Oriental spruce (Spruce orientalis) for biodiesel production. Two methods have been applied for obtained wood oil with and without solvent such as separation of crude tall oil from sulfate soaps by Kraft pulping process. Production of biodiesel from wood oil follows two steps, first extraction of oil using a solvent (acetone) and then base catalyzed (KOH) or non-catalytic supercritical methanol transesterification. This paper studied the effect of temperature on transesterification of wood oil to find the optimum temperature of maximum biodiesel yield. Transesterification of the wood oils were performed in a 100-mL cylindrical autoclave using supercritical methanol. In a typical run, the autoclave was charged with a given amount of the wood oil (20-25 g) and alcohol (20-50 g) with changed molar ratios at 500, 525, 550 and 575 K. The yield of the biodiesel produced under optimal condition is 96-98%.     

Lipase‐catalyzed production of biodiesel from rice bran oil

Biodiesel has attracted considerable attention as an alternative fuel during the past decades. The main hurdle to the commercialization of biodiesel is the cost of the raw material. Use of an inexpensive raw material such as rice bran oil is an attractive option to lower the cost of biodiesel. Two commercially available immobilized lipases, Novozym 435 and IM 60, were employed as catalyst for the reaction of rice bran oil and methanol. Novozym 435 was found to be more effective in catalyzing the methanolysis of rice bran oil. Methanolysis of refined rice bran oil and fatty acids (derived from rice bran oil) catalyzed by Novozym 435 (5% based on oil weight) can reach a conversion of over 98% in 6 h and 1 h, respectively. Methanolysis of rice bran oil with a free fatty acid content higher than 18% resulted in lower conversions (<68%). A two‐step lipase‐catalyzed methanolysis of rice bran oil was developed for the efficient conversion of both free fatty acid and acylglycerides into fatty acid methyl ester. More than 98% conversion can be obtained in 4–6 h depending on the relative proportion of free fatty acid and acylglycerides in the rice bran oil. Inactivation of lipase by phospholipids and other minor components was observed during the methanolysis of crude rice bran oil. Simultaneous dewaxing/degumming proved to be efficient in removing phospholipids and other minor components that inhibit lipase activity from crude rice bran oil. Copyright © 2005 Society of Chemical Industry     

Determination of free fatty acids in palm oil by near-infrared reflectance spectroscopy

A near-infrared (NIR) spectroscopy calibration was developed for the determination of free fatty acids (FFA) in crude palm oil and its fractions based on the NIR reflectance approach. A range of FFA concentrations was prepared by hydrolyzing oil with 0.15% (w/w) lipase in an incubator at 60°C (200 rpm). Sample preparation was performed in Dutch cup, and the spectra were measured in duplicate for each sample. The optimized calibration models were constructed with multiple linear regression analysis based on C=O overtone regions from 1850–2050 nm. The best wavelength combinations were 1882, 2010, and 2040 nm. Multiple correlation coefficients squared (R ²) were: 0.994 for crude palm oil, 0.961 for refined-bleached-deodorized (RBD) palm olein, and 0.971 for RBD palm oil. Calibrations were validated with an independent set of 8–10 samples. R ² of validation were 0.997, 0.943, and 0.945, respectively. The developed method was rapid, with a total analysis time of 5 min, and environmentally friendly, and its accuracy was generally good for raw-material quality control.