"人工神经网络"方法用于超临界流体萃取模拟

在15－30MPa和303－323K条件下，用超临界CO2流体萃取沙棘籽油，结果表明，最高沙棘油收率（30MPa,308K)可达到90％以上，对过程进行动力学模拟，建立了超临界萃取过程的人工神经网络（ANN）模型，以MATLAB软件为平台，编制了SFE－ANN模拟程序系统，采用3层BP网络结构，以压力，温度、萃取时间为输入，以萃取出油量为输出对网络进行训练，由此得到的网络可以对萃取速率和单位时间床高方向的萃取出油量进行准确的模拟和预测，与实验结果比较证明，训练样本集误差为0．2％，测试样本集误差为0．5％，模拟误差小于6％。     

超临界CO_2萃取大豆油的实验研究

采用超临界CO2 萃取技术进行了大豆油的萃取实验。在压力为 2 0～ 30MPa、温度为 30 8～ 32 3K的范围内 ,考察了萃取压力、萃取温度、流体流量和物料预处理方式等条件对出油率的影响。在本文实验范围内 ,大豆油的最佳萃取工艺条件为 :压力 30MPa ,温度 313K ,物料状态为约 0 .4mm厚的大豆片。流体流量只影响萃取速率 ,而不影响最终的出油率     

超临界二氧化碳萃取枸杞籽油的实验研究与数值模拟

建立了一套超临界流体萃取枸杞籽油的实验流程。以二氧化碳为萃取剂,考察了萃取压力、操作温度、二氧化碳流量及原料颗粒度等因素对枸杞籽油萃取率的影响。确定了较佳的萃取工艺条件:压力30MPa,温度313～318K,枸杞籽颗粒40～50目,二氧化碳流量0.3～0.4m3/h时枸杞籽油萃取率最高,可达15.5%。基于萃取器微分单元和固态颗粒微分单元质量守恒原理,建立了微分方程,利用直线推动力近似理论拟合总传质推动力及平衡吸收常数,化简方程,对部分实验结果进行数值模拟。     

邻羟基苯甲酸和邻甲氧基苯甲酸在超临界CO2中的溶解度研究

采用流动法测定和研究了邻羟基苯甲酸和邻甲氧基苯甲酸在308K、328K下,10．0～24．0MPa范围内,在纯超临界CO2中的溶解度,并简要分析分子极性和结构特点对固体溶质溶解度大小的影响。同时,将超临界流体视为膨胀液体,根据溶液理论,建立了计算溶质在超临界流体中溶解度的膨胀液体模型。应用该模型对试验数据进行回归,得到了令人满意的结果。     

超临界CO_2流体萃取牡丹鲜花提取物工艺研究

为研究超临界二氧化碳流体萃取牡丹鲜花提取物的工艺,以牡丹鲜花提取物得率为衡量工艺参数的指标,采用正交试验确定超临界二氧化碳流体萃取的最佳条件。结果发现,超临界二氧化碳流体萃取的最佳工艺为:萃取压力30 MPa、萃取温度55℃;分离器I压力8 MPa、分离器I温度65℃;分离器Ⅱ压力8 MPa、分离器II温度20℃。其中牡丹鲜花浸膏平均得率为0.405%,牡丹鲜花提取液的平均得率为8.95%。     

超临界CO2萃取胡椒油实验研究与数值模拟

建立了超临界流体萃取胡椒油实验装置,以CO2为萃取剂,考察了萃取压力、温度、CO2流量及原料颗粒大小等因素对胡椒油萃取率的影响,并由此确定了较佳的萃取工艺条件:压力22—26 MPa,温度313—323 K,胡椒颗粒度30—40目,CO2流量0.3—0.4 m3/h,胡椒油累积萃取率可达80%—90%。基于萃取器微分单元和固态原料颗粒微分单元质量守恒原理,建立了微分方程,利用直线推动力近似理论拟合总传质推动力及平衡吸收常数,化简方程,对实验结果进行了数值模拟。     

二氧化碳超临界萃取乙基香兰素粗制品的研究

采用二氧化碳超临界萃取乙基香兰素粗品,研究萃取压力、萃取温度、萃取时间、流体流量等工艺条件对萃取效率和产品质量的影响.得出最佳工艺条件,采用萃取压力25～30 MPa,萃取温度55～60℃,流体流量5 L/h,萃取5～6 h,萃取效率可以达到95％,可以得到质量分数大于95％的乙基香兰素产品.     

超临界流体CO_2提取虎杖中的有效成分

以大黄素为指标对虎杖中的有效成分进行超临界流体CO2萃取。用正交设计法考察了最优萃取条件。影响超临界流体萃取率的主要因素依次是:动态流量、温度、压力、时间;确定了大黄素的最佳萃取条件是:萃取压力25 MPa,萃取温度55℃,动态流量8 kg/h,萃取时间30 m in。超临界流体萃取大黄素的提取率达0.36%。     

动力学模拟超临界流体从香椿叶中萃取黄酮类化合物

首先介绍了三种动力学模拟超临界流体萃取的模型(经验模型、基于热传递类推的模型以及基于微分质量平衡的模型),然后模拟了在超声存在的条件下超临界流体从香椿叶中萃取黄酮类化合物的动力学过程,最后通过该例子展示了现有大多数动力学模型的缺点.     

二氧化碳超临界萃取酸性水溶液中3-甲氧基-4-羟基苯甲醛的研究

采用二氧化碳超临界萃取酸性水溶液中3-甲氧基-4-羟基苯甲醛(香兰素),含有3-甲氧基-4-羟基苯甲醛的水溶液与超临界二氧化碳流体在萃取柱中连续逆流混合,研究得出最佳工艺条件:压力(22～26)MPa;萃取温度55～60℃,超临界流体与原料液体质量比5.5:1,此条件下,萃取效率95%以上,可以得到质量分教大于90%的产品.     

Soybean oil extraction in belt extractors with miscella recirculation

This work presents a mathematical model for soybean oil extraction in a belt extractor with miscella recirculation. The mathematical model consists of partial differential and algebraic equations and it takes into account the extractor dimension and the physical properties of the solid and miscella. Experimental data collected in an industrial process in Stead State were used to check the model validity. The model was solved using the Finite Difference Method in a computational routine developed in Maple™ and it was compared with the Method of Ideal Stages. The results are coherent and consistent with the extraction phenomena and they can be used to evaluate the influence of several parameters and to obtain the soybean oil concentration profile in any of the phases and parts of the extractor, either in vertical or horizontal arrangement.     

乙醇抽提大豆油之研究

<正> 大豆产于我国已有长久历史,产量向居世界第一位.据1949年统计,全世界大豆产量为501,700,000英斛(bushel)(1 bushel=8加侖),中国产量为245,200,000英斛,约占全世界产量二分之一弱;1935—1939年世界平均产量为464,300,000英斛,中国为369,111,000英斛,约佔四分之三强,故大豆为我国国宝之一.大豆不但含有丰富之蛋白质等,为极佳之食品,且平均含油量达18%左右,为吾国同胞食油之主要来源.     

Solvent extraction of vegetable oils: Numerical and experimental study

A process for the extraction of vegetable oils from soybean seeds with a solvent was developed experimentally. The extraction was carried out in a continuous, fixed-bed extractor. A non-dimensional transient model was applied to simulate the mass transfer process which occurs during the extraction in a packed bed column. The governing dimensionless differential equations were numerically solved using the method of finite volumes. The numerical results were compared with data obtained from the experimental extraction, presenting good agreement. The values obtained numerically for the total oil mass extracted in the fluid phase presented a maximum error of 20%, when compared to the experimental data. The greatest discrepancy was observed at the end of the extraction. This maximum error can be considered small due to the use of a simple numerical model.     

Chlorine-Containing compounds as copper catalyst poisons

The effect of chlorine-containing substances on the rate of the copper chromite-catalyzed hydrogenation of soybean oil has been investigated. Using chlorinated soybean oil as a model substance, it was found that amounts corresponding to 25, 50 and 90 ppm Cl markedly decreased the rate of hydrogenation when added to a 0.5% Cu run at 170 C. Similar effects were found with various chlorinated alkanes. It was also found that the refined and bleached soybean oil contained noticeable amounts of an unknown catalyst poison. This made if difficult to calculate specific poisoning constants for chlorine (% Cu/ppm Cl). Attempts have been made to estimate minimal values for this constant.     

The Brazilian soybean situation and its impact on the world oils market

Brazil has come from obscurity to become the worlds second largest producer and exporter of soybeans. Internal crushing has also expanded rapidly and become more specialized in soybean crushing. In 1978 Brazilian soybean crushing capacity reached about 14 million metric tons (MT). Domestic oil and meal price ceilings and bean export restric-tions have had a significant effect on the growth in Brazil’s crushing capacity. Since 1975 exports of both soybean meal and oil have received favored export treatment relative to soybeans. Brazil is likely to continue restrictions on bean exports to ensure availability of beans to their crushers. Brazil’s annual soybean production is likely to grow from the 12 million metric tons in 1977 to over 15 million tons by 1982, with exports of 1-2 million tons. Meal exports are expected to grow by 1-2 million tons and oil exports marginally from 1978 levels by 1982. The long run soybean production will depend on how much expansion occurs in the Central West, where the soil is less fertile and production and transport costs are much higher. Substantial expansion there will require higher world soybean prices, construction of marketing and transportation infrastructure, and subsidization of input costs. 1Journal Paper No. 7507, Indiana Agricultural Experiment Station. Revision of paper presented at the Commodity Oil Markets’ Symposium at the AOCS Meeting, St. Louis, May 1978.     

Concentration of Natural Vitamin E Using a Continuous Countercurrent Supercritical CO2 Extraction‐Distillation Dual Column

A continuous countercurrent supercritical CO₂ extraction‐distillation dual‐column process was developed to extract and concentrate natural vitamin E (VE) from soybean oil deodorizer distillate (SODD). The experimental results demonstrated that process parameters such as extraction pressure, temperature, and solvent‐to‐feed ratio significantly impacted on the extraction efficiency of natural VE. A new five‐parameter mass transfer model for the continuous countercurrent supercritical CO₂ extraction‐distillation dual‐column process was presented based on the Penetration and Double‐Film theories. The calculated values of the mathematical model agreed well with the experimental data, with absolute average relative deviation values of less than 25 %.     

Composition of oils extracted from potato chips by supercritical fluid extraction

To determine effects of two extraction procedures on oil compositions, tocopherols, monoacylglycerol, diacylglycerol, triacylglycerol, free fatty acids, polymers and polar components were determined in oils after extraction from potato chips by either supercritical carbon dioxide or hexane. Potato chips were fried in cottonseed oil or low linolenic acid soybean oil and sampled after 1, 10 and 20 h of oil use. Both extraction methods recovered comparable amounts of oil from the potato chips. Compositions of triacylglycerol and non‐triacylglycerol components including tocopherols, monomer, polymer, monoacylglycerol, diacylglycerol were similar for samples of chips fried in either oil except for the δ‐tocopherol data for potato chips fried in the low linolenic acid soybean oil used for 10 h of frying. There were some differences between the composition of low linolenic acid soybean oil extracted from the potato chips compared to the fryer oil at the 20 h sampling time. These results showed that the supercritical carbon dioxide extraction gave similar results to hexane extraction in yield and composition of oils from potato chips.     

Hexane elimination from soybean oil by continuous packed tower processing with supercritical CO2

Hexane elimination is the most energy-consuming step in the industrial extraction of soybean oil. It utilizes three sets of equipment: two evaporation stages in series followed by a stripper at a pressure of about 0.07 bar. The final hexane residue in the oil is about 1000 ppm. We propose an alternative to the present process for hexane elimination, based on the extraction of the soybean oil/hexane mixture with supercritical CO₂ in a continuous countercurrent packed tower. In this work, we tested a soybean oil/hexane mixture feed containing 10% by weight of hexane. Various pressures and temperatures of the column were tested to reduce hexane residue in the oil. The extraction process was demonstrated to be very effective for hexane separation. Indeed, at the bottom of the column we recovered soybean oil containing quantities of hexane as low as 20 ppm when we operated at 120 bar, 40°C. The effect of process parameters is also discussed.     

Analysis of the oil extraction process in soybeans: A new continuous procedure

Soybean oil extraction techniques were studied in which solvent was recirculated or pumped once through a suspension of soybean tissue. Both refractive index and ultraviolet absorbance were used to monitor the extraction continuously. Slices of soybean tissue showed rapid extraction from damaged tissue, followed by slow extraction from intact tissue. When soybean flakes were extracted, a continuously decreasing rate was noted. When solvent was forced through flakes, extraction was more rapid than when solvent was allowed to diffuse in and out of flakes. Reextraction of partially defatted flakes showed that the last soybean oil to be extracted was not inherently resistant to extraction. The adsorption of soybean oil to defatted flakes may account for slow removal of small quantities of oil at the end of the extraction.