分子蒸馏技术概要.pptx

李彩彩 M201370197分子蒸馏简介相关文献讲解分子蒸馏简介产生背景基本概念原理及特点相关应用一、产生背景一、产生背景1、常规蒸馏、常规蒸馏 通常是指将液相加热至沸腾后再将气相冷凝，从通常是指将液相加热至沸腾后再将气相冷凝，从而实现混合物的分离，其实质是利用了不同物质而实现混合物的分离，其实质是利用了不同物质间的间的沸点差沸点差来完成的。来完成的。常规蒸馏常规蒸馏 热敏性物质的分离无能为力热敏性物质的分离无能为力 2、真空蒸馏、真空蒸馏 将物料放置在一加热釜中蒸发，并在釜外冷凝器将物料放置在一加热釜中蒸发，并在釜外冷凝器后配置上真空系统，由于操作压力的降低，物料后配置上真空系统，由于操作压力的降低，物料的沸点随之下降，从而使操作温度降低。的沸点随之下降，从而使操作温度降低。其蒸发面上的实际操作压力仍然比较高其蒸发面上的实际操作压力仍然比较高 热敏性、高沸点物系的分离无能为力热敏性、高沸点物系的分离无能为力 问题出现了，如何解决？分子蒸馏技术分子蒸馏技术 突破了传统蒸馏利用突破了传统蒸馏利用沸点差沸点差实现分离的实现分离的原理，通过利用原理，通过利用分子运动平均自由程的差分子运动平均自由程的差别别实现物质的分离，从而使物料在远离沸实现物质的分离，从而使物料在远离沸点下进行蒸馏分离成为可能点下进行蒸馏分离成为可能.分子蒸馏分子蒸馏 一种在高真空下操作的蒸馏方法，这时蒸气分子的平均自由程大于蒸发表面与冷凝表面之间的距离，从而可利用料液中各组分蒸发速率的差异，对液体混合物进行分离二、基本概念二、基本概念n分子碰撞分子碰撞 分子与分子之间存在着相互作用力，当两分子离得较远时，分子之间的作用力表现为吸引力，但当两分子接近到一定程度后，分子之间的作用力会改变为排斥力，并随其接近距离的减小，排斥力迅速增加。当两分子接近到一定程度时，排斥力的作用使两分子分开。这种由接近而至排斥分离的过程就是分子的碰撞过程。n分子有效直径分子有效直径 分子在碰撞过程中，两分子质心的最短距离（即发生斥离的质心距离）称为分子有效直径。n分子运动自由程分子运动自由程 一个分子在相邻两次分子碰撞之间所经过的路程n分子运动平均自由程分子运动平均自由程 任一分子在运动过程中都在不断变化自由程，而在一定的外界条件下，不同物质的分子其自由程各不相同。在某时间间隔内自由程的平均值称为平均自由程。n影响分子自由程的因素及分离因素 根据麦克斯韦速度分布，对单一气体的平均自由程可由下述公式进行计算：=2.3310-2*T*p-1*-2式中：T温度 P真空压力分子的直径n分子蒸馏的分离能力 分子蒸馏用分离因素M表示 式中：P1、P2分别为轻重组分的蒸汽压 M1、M2分别为轻重组分的分子量三、原理及特点1、分子蒸馏基本原理分子蒸馏过程（四步曲）(1)扩散：物料分子从液相主体向蒸发表面扩散。注意：液相中的扩散速度是控制分子蒸馏速度的主要因素(2)蒸发：物料分子在液层上自由蒸发速度随温度升高而增大,但分离因素却随温度升高而降低。(3)飞射：分子从蒸发面向冷凝面飞射。该过程中分子可能与残存的空气分子碰撞,也可能相互碰撞,但只要真空度合适,使蒸发分子的平均自由程大于或等于蒸发面与冷凝面之间的距离即可。(4)冷凝：轻分子在冷凝面上冷凝。如果冷凝面的形状合理且光滑并迅速转移,则可以认为冷凝是瞬间完成的分子蒸馏应满足的两个条件：轻、重分子的平均自由程必须要有差异，且差异越大越好；蒸发面与冷凝面间距必须小于轻分子的平均自由程 2、分子蒸馏技术的特点分子蒸馏技术的特点 1.操作温度低 2.蒸气压强低 3.受热时间短 4.不可逆性 5.没有沸腾鼓泡现象 6.分离程度及产品收率高 7.无毒、无害、无污染、无残留3、分子蒸馏的适用范围1.分子蒸馏适用于不同物质分子量差别较大的液体混合物系的分离，特别是同系物的分离，分子量必须要有一定差别。2.分子蒸馏也可用于分子量接近但性质差别较大的物质的分离，如沸点差较大、分子量接近的物系的分离。3.分子蒸馏特别适用于高沸点、热敏性、易氧化（或易聚合）物质的分离4.分子蒸馏适宜于附加值较高或社会效益较大的物质的分离。5.分子蒸馏不适宜于同分异构体的分离4、分子蒸馏技术的局限性由于分子蒸馏要求在高真空下进行分离,所需要的设备成本过高,结构复杂,设计技术要求高,相应的配套设备也多,投资过大,国内尚未见大规模运用;分子蒸馏受设备结构和加热面积的限制,设备体积比常规蒸馏设备体积大,在大规模生产应用中有不少困难。5、分子蒸馏设备n分子蒸馏器的模式（1）降膜式结构简单。液膜靠重力自然分布下降，较厚，效率低，目前已很少使用；（2）刮膜式依靠刮板成膜，较薄，分离效率高，但结构较降膜式复杂。现在国内、外的工业化装置以转子刮膜式为主。（3）离心式依靠离心力成膜，很薄，蒸发效率最高，但结构也最复杂，造价高n分子蒸馏器的模式（1）降膜式分子蒸馏器 液膜厚度小,蒸馏物料可沿蒸发表面流动,停留时间短,热分解的危险性较小,蒸馏过程可以连续进行,生产能力大。很难保证所有的蒸发表面都被液膜均匀覆盖,液体流动时常发生翻滚现象,产生的雾沫也常溅到冷凝面上,影响分离效果。（2）刮膜式蒸发器 其结构的主要特点是在刷膜式釜中设置一聚四氟乙烯制的转动刮板,既保证液体能够均匀覆盖蒸发表面,又可使下流液层得到充分搅动,从而强化了物料的传热和传质过程,提高了分离效能。（3）离心式蒸发器 液膜在旋转的转盘表面形成的液膜极薄且分布均匀,蒸发速率和分离效率很高。受热时间更短,料液热裂解的几率低。连续处理量更大,因此该装置更适合于工业化连续性生产。n分子蒸馏设备分子蒸馏设备：实验室设备实验室设备分子蒸馏设备：中试型设备：中试型设备：MD-S150 分子蒸馏设备：MD-S300 分子蒸馏设备：MD-S500分子蒸馏设备：MD-S900 1000吨吨/年分子蒸馏单甘脂装年分子蒸馏单甘脂装置置分子蒸馏设备：MDL-150（离心式）（离心式）四、相关应用四、相关应用n石油化工方面石油化工方面n塑料工业方面塑料工业方面n食品工业方面食品工业方面n医药行业方面医药行业方面 n香料工业方面香料工业方面 制药1 酸性氯化物酸性氯化物 2 氨基酸酯氨基酸酯 3 葡萄糖衍生物葡萄糖衍生物 4 吲哚吲哚 5 萜酯萜酯 6 天然和合成维生素天然和合成维生素 7 互叶白千层油互叶白千层油 8 辣椒碱辣椒碱 9 大蒜素的精制大蒜素的精制 10 川芎川芎 11 当归当归 12 姜油姜油13 中草药有效成分的提纯中草药有效成分的提纯 化工1 1醇类醇类 2.2.酯酯 3.3.乙二醇醚乙二醇醚 4.4.除草剂除草剂 5.5.全能碳氢化合物全能碳氢化合物 6 6杀虫剂杀虫剂 7.7.硅油硅油 8.8.妥尔革柔油妥尔革柔油 塑料1环氧树脂环氧树脂 2.环氧化油环氧化油 3.异氰酸盐异氰酸盐 4.增塑剂增塑剂 5.稳定剂稳定剂 石油化工1 1盐基油盐基油 2.2.亮库存油亮库存油 3.3.润滑油润滑油 4.4.石蜡油石蜡油 5.5.沥青残留物沥青残留物 6.6.焦油焦油 日化1羊毛酯酸羊毛酯酸 2.羊毛酯醇羊毛酯醇 3.烷基多酣烷基多酣 4.海藻、金雀花、褐苔、鲜花、海藻、金雀花、褐苔、鲜花、根菜根菜作物、辣椒的提取物作物、辣椒的提取物 香料香精1 1广藿香油广藿香油 2.2.玫瑰油玫瑰油 3.3.山苍子油山苍子油 4.4.桉叶油（茶树油）桉叶油（茶树油）5.5.香茅油香茅油 6.6.橙油橙油 7.7.紫罗兰酮紫罗兰酮相关文献讲解 选题背景方法思路结果讨论Fractionation and Characterization of a Petroleum Residue by Molecular Distillation Process一、选题背景一、选题背景1.The upgrading of a high-boiling atmospheric residue or other crude oil fractions is of signifant.2.However,the maximum AEBP achieved for most atmospheric residue by vacuum distillation is 565C3.For higher temperatures a well-established method does not exist.So a methodology based on a molecular distillation(MD)process was implemented：a falling film molecular distillation二、方法思路二、方法思路 1.The falling film molecular distillation prototype was used for fractionating AR-B.2.To verify the efficiency of the molecular distillation process to fractionate the 400 C AR-B,physicochemical properties of the products(four distillate cuts and four residues)were determined.It included the analysis of viscosity,density,SARA fractionating,molecular weight,and elemental composition of fractions.3.To extended the TBP Curve AEBP=456.4+0.1667TMD+1.64*10-4TMD2+4.13*10-6TMD3 This equation is applicable to AEBP above to 540C and the TBP curve presents great continuity from this temperature.三、结果讨论三、结果讨论 1.The converted molecular distillation operating conditions were plotted in association with the TBP curve of the crude oil“B”to extend the curve until 662 C.At this temperature,the distillate yield was 82.0%representing a gain of 11.7%in the amount of distillate when compared to conventional distillation.the MD equipment was capable to generate fractions with a remarkable difference in their composition,satisfying the objective of the process since the components with higher structural complexity were concentrated as the molecular distillation temperature rose.From the SARA analysis,it is expected that the polarity of the residue fractions from MD increase as the fraction became heavier.The end-cut residues(662 C+)had the highest polarity because of the highest asphaltene content among all fractionsConclusion molecular distillation equipment was an efficient way to produce fractions with lower proportion of compounds with complex molecular structures,and the operation conditions of the molecular distillation process generate distillate cuts with an AEBP above 600C without risks of thermal degradation.This is an important result since it increases the scope of the characterization of the crude oil.Enrichment of cuminaldehyde and p-mentha-1,4-dien-7-al in cumin(Cuminum cyminum L.)oil by molecular distillation一、选题背景一、选题背景 In recent years,extensive studies were conducted on functional activities of cumin oil(CUO),including antimicrobial,insect-resistant,antioxidant,stomachic,anti-epileptic,anticancer，and anti-diabetic.The functional activities were determined by the components of the cumin oil.Our preliminary study showed that cuminaldehylde and p-1,4-mentha-dien-7-al were the major components of CUO,and they were probably the active ingredients.So the enrichment of cuminaldehylde and p-1,4-mentha-dien-7-al in CUO was very necessary for its further application in food and pharmaceutical industriesMD:1.with no deterioration of its natural properties2.without using any organic solvents in the purification process3.a preferential choice for separating of heatsensitive active materials二、方法思路二、方法思路1.Cumin essential oil(CEO)was purified by wiped-film MD apparatus2.Suitable values for the two distilling factors,T and P were selected as the independent variables3.The experimental design employed for the analysis was a central composite rotate design(CCRD)（The response variables(Yn)considered were distillates yield(Y1),content of cuminaldehyde in distillates(Y2),content of p-mentha-1,4-dien-7-al in distillates(Y3),content of cuminaldehyde in residues(Y4),content of p-mentha-1,4-dien-7-al in residues(Y5），），X1 and X2 were the coded values of distilling temperature and pressure）4.A quadratic polynomial regression model was assumed for predicting all Yresponses(Y1Y5)Y=A0+A1X1+A2X2+A11X12+A12X1X2+A22X225.Response surface methodology(RSM)and perturbation plots were used for modeling and analyses of the purification process三、结果讨论三、结果讨论Influence of distilling temperature and distilling pressure on the distillates yield Y1=73.65-3.37*X1-14.15*X2+11.89*X1X2-26.16*X121.The region of high distillates yield which could be easily identified from the three-dimensional plot was around 2835and 1330 Pa2.When the temperature was conducted at 35,the distillates yield decreased with the increasing of the distilling pressure(curveB)The distillates yield increased as the distilling temperature increased from 20 to 35,and then decreased over 35(curveA)Conclusions Through comprehensive analysis on the yield and purities of cuminaldehyde andpmentha-1,4-dien-7-al,the optimal parameters were determined as the distilling temperature 30 and distilling pressure 19 Pa.Thedistillates yield,contents of cuminaldehylde andp-mentha-1,4-dien-7-al were 81.23%,38.93%and 55.75%,respectively.MD was a valuable alternative technique for the enrichment of cuminaldehylde and p-mentha-1,4-dien-7-al in cumin oil.谢 谢