掺杂镧的固体酸制备及其催化合成生物柴油的应用研究

发布时间：2018-07-23 14:14

【摘要】：近年来,随着人们生活质量的提高,对环境要求越来越高,希望在低碳、低污染环境中生活、学习和工作。生物柴油作为一种环保、可再生的生物质能源,可直接代替石油等矿物能源,对环境保护和资源节约具有重要意义。目前,地沟油可与甲醇经碱催化可合成绿色能源生物柴油;但地沟油酸值太高,合成生物柴油过程中,地沟油中的游离脂肪酸易与碱性物质发生皂化反应,极大地影响了生物柴油的产率。因此,亟需解决高酸值问题。固体酸催化剂可以降低地沟油的酸值,且较均相酸性催化剂具有易分离、对设备腐蚀程度小,对合成生物柴油起着巨大作用。本论文以高酸值地沟油为原料,重点研究了固体酸的制备与表征、酯化反应合成酯化油及酯交换反应合成生物柴油整个应用过程。本论文研究成果有助于促进生物柴油产业技术水平的进步和产品质量的提高,创造良好的经济效益和环境效应。主要研究内容如下:(1)本论文以活性炭为基质、TiO_2和La_2O_3为改性剂、浓硫酸为活化剂,采用高温磺化法制备复合型稀土改性固体酸SO_4~(2-)/C-TiO_2-La_2O_3。探讨La_2O_3的质量分数、磺化反应温度、磺化反应时间对固体酸催化剂制备条件的影响。通过实验结果表明,固体酸催化剂制备SO_4~(2-)/C-TiO_2-La_2O_3的最佳工艺条件为:La_2O_3的质量分数为3%(以活性炭质量计,下同)、磺化温度为200℃、磺化时间为10 h。(2)采用扫描电镜(SEM)、透射电镜(TEM)、红外光谱(FT-IR)、X射线衍射(XRD)、比表面积(BET)、能谱分析(EDS)、热重分析(DTG)分别对固体酸进行表征分析。固体酸SO_4~(2-)/C-TiO_2-La_2O_3最佳制备条件:La_2O_3的质量分数为3%、磺化时间为10 h、磺化温度为200℃;固体酸SO_4~(2-)/C-TiO_2-La_2O_3的比表面积最大、粒径最小,分别为53.82 m2/g和156.91 nm;固体酸SO_4~(2-)/C-TiO_2-La_2O_3的酸位中心数量最多;固体酸SO_4~(2-)/C-TiO_2-La_2O_3中的O、S、Ti、La原子比其他三种固体酸多;固体酸SO_4~(2-)/C-TiO_2-La_2O_3热稳定性最强。(3)通过比较四种固体酸SO_4~(2-)/C、SO_4~(2-)/C-TiO_2、SO_4~(2-)/C-La_2O_3、SO_4~(2-)/C-TiO_2-La_2O_3的催化活性,固体酸SO_4~(2-)/C-TiO_2-La_2O_3的催化活性相对其他三种固体酸要高一些,因此,选择固体酸SO_4~(2-)/C-TiO_2-La_2O_3为催化剂,催化经处理过的地沟油与甲醇发生酯化反应,酯化率作为衡量对象,考察固体酸SO_4~(2-)/C-TiO_2-La_2O_3的质量分数、反应时间、反应温度、甲醇与地沟油的比对酯化率的影响。结果指明:固体酸SO_4~(2-)/C-TiO_2-La_2O_3的质量分数为2.5%(以地沟油的质量计,下同)、酯化反应的时间为4 h、酯化反应的温度为65℃、甲醇与地沟油的质量比为1:5,在此条件下酯化率最大,达到95.64%,将地沟油的酸值从18.97mg(KOH)/g下降至1.10 mg(KOH)/g,得到酯化油,酯化油为后续的酯交换反应使用。(4)以碱性催化剂NaOH为酯交换反应的催化剂,将NaOH与甲醇配制成NaOH-甲醇溶液,与酯化油在一定的条件下发生酯交换反应,以粗品生物柴油得率为考察目标,探讨催化剂NaOH的质量分数(以酯化油质量计,下同)、酯交换反应时间、酯交换反应温度、甲醇与酯化油的质量比四个因素对粗品生物柴油层得率的影响。结果表明,合成生物柴油的最佳条件是:催化剂NaOH的质量分数为0.4%、酯交换反应的时间为1 h、酯交换反应的温度为65℃、醇油质量比为3:20,此时粗品生物柴油的得率为95.90%。(5)检测产品生物柴油的凝点为-2℃、运动粘度为5.0 mm2/s、铜片腐蚀度为1级、密度为878 Kg/m3、闭口闪点为160℃、胶质为1000 mg/100mL、酸值为0.28 mg(KOH)/g、硫含量为0.02%(W/W)、十六烷值为44,其性能基本符合国标。因此,合成的生物柴油具有一定的研究价值和使用价值。
[Abstract]:In recent years, with the improvement of people's quality of life, the demand for the environment is getting higher and higher, hoping to live, study and work in low carbon and low pollution environment. As a kind of environmental protection and renewable biomass energy, biodiesel can directly replace petroleum and other mineral energy. It is of great significance to environmental protection and resource conservation. In the process of synthetic biodiesel, the free fatty acids in the gutter oil are easily saponified with the basic substances, which greatly affects the yield of biodiesel. Therefore, the high acid value problem is urgently needed. The solid acid catalyst can reduce the acid value of the gutter oil and is more than the same. The homogeneous acid catalyst is easy to be separated and has a small corrosion degree to the equipment. It plays a great role in the synthesis of biodiesel. This paper focuses on the preparation and characterization of solid acid, esterification synthesis of esterified oil and ester exchange reaction to synthesize biodiesel oil. Improving the technological level of biodiesel industry and improving the quality of products to create good economic and environmental effects. The main contents are as follows: (1) this paper uses activated charcoal as matrix, TiO_2 and La_2O_3 as modifier, concentrated sulfuric acid as activator, and the preparation of compound rare earth modified solid acid SO_4~ (2-) /C-TiO_2-La by high temperature sulfonated method The effect of the mass fraction of La_2O_3, the temperature of sulfonation reaction and the time of sulfonation reaction on the preparation conditions of solid acid catalyst were investigated by _2O_3.. The optimum process conditions for the preparation of SO_4~ (2-) /C-TiO_2-La_2O_3 by solid acid catalyst were as follows: the mass fraction of La_2O_3 was 3% (with the activated carbon mass meter, the same below), the sulfonation temperature was 200, and the sulfonation was sulfonated. The time was 10 h. (2) by scanning electron microscope (SEM), transmission electron microscope (TEM), infrared spectroscopy (FT-IR), X ray diffraction (XRD), specific surface area (BET), energy spectrum analysis (EDS) and thermogravimetric analysis (DTG), respectively. The optimum preparation conditions for solid acid SO_4~ (2-) /C-TiO_2-La_2O_3 were 3%, 10 sulfonated and sulfonated. The specific surface area of solid acid SO_4~ (2-) /C-TiO_2-La_2O_3 is the largest and the particle size is the lowest, 53.82 m2/g and 156.91 nm respectively. The solid acid SO_4~ (2-) /C-TiO_2-La_2O_3 has the largest number of acid sites, and the O of solid acid SO_4~ (2-) /C-TiO_2-La_2O_3 is more than the other three kinds of solid acids. Solid acids are more than solid acids. (3) by comparing the catalytic activity of four solid acids SO_4~ (2-) /C, SO_4~ (2-) /C-TiO_2, SO_4~ (2-) /C-La_2O_3, SO_4~ (2-) /C-TiO_2-La_2O_3, the catalytic activity of solid acids is higher than that of the other three solid acids. The effect of the esterification reaction and the esterification rate on the esterification rate of SO_4~ (2-) /C-TiO_2-La_2O_3 of solid acid, reaction time, reaction temperature, and the ratio of methanol to gutter oil were investigated. The results indicated that the mass fraction of solid acid SO_4~ (2-) / C-TiO_2-La_2O_3 was 2.5% (with the quality of gutter oil, The esterification reaction time is 4 h, the esterification reaction temperature is 65, the mass ratio of methanol to the gutter oil is 1:5, and the esterification rate is maximum, reaching 95.64%. The acid value of the gutter oil decreases from 18.97mg (KOH) /g to 1.10 Mg (KOH) /g. The esterified oil is obtained and the ester oil is used for the subsequent ester exchange reaction. (4) the alkaline catalyst NaOH is the ester. The catalyst of the exchange reaction was made up of NaOH and methanol into a NaOH- methanol solution, and the esterified oil was transesterified under certain conditions. The mass fraction of the catalyst NaOH (with the esterified oil mass, the same below), the ester exchange reaction time, the transesterification reaction temperature, the methanol and the quality of the esterified oil were investigated. The effect of four factors on the yield of crude biodiesel is measured. The results show that the optimum conditions for the synthesis of biodiesel are as follows: the mass fraction of the catalyst NaOH is 0.4%, the time of the transesterification is 1 h, the temperature of the transesterification is 65, the mass ratio of the alcohol oil is 3:20, and the yield of the crude biodiesel is 95.90%. (5) for the detection of the bio diesel fuel. The oil condensation point is -2 C, the moving viscosity is 5 mm2/s, the copper plate corrosion degree is 1, the density is 878 Kg/m3, the closing flash point is 160 C, the gum is 1000 mg/100mL, the acid value is 0.28 Mg (KOH) /g, the sulfur content is 0.02% (W/W), and the sixteen alkanes value is 44. The performance of the synthetic biodiesel has certain research value and use value.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE667;TQ426

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