Process engineering economic evaluation of the ethanol extraction of cottonseed: Preliminary analysis

This preliminary analysis was undertaken to determine if the operations being developed for the aqueous ethanol extraction of cottonseed oil are economical and whether further research of this process should be pursued. Results of the conversion of hypothetical hexane extraction plants to ethanol extraction, in the plant capacity range of 300-600 tons of cottonseed flakes/day and operating 150-350 days annually, show that two unconventional operations, namely, chill-separation of miscella exiting the extractor and reduction of oil in recycled ethanol by reverse osmosis, require less energy and are less expensive than conventional alternatives. However, additional work is needed to determine the overall efficiency of an alcohol process as compared to a conventional hexane process.     

An aqueous ethanol extraction process for cottonseed oil

A bench-top process for the extraction of cottonseed flakes with aqueous ethanol has been developed. The process consists of cottonseed meat flaking, drying and extraction with boiling, aqueous ethanol (95% by volume) at atmospheric pressure. The resulting miscella is chilled, producing free oil, emulsified oil and mucilaginous gum. The heterogeneous solution is processed through a phase separator where free and emulsified oil and gum are separated from oil-lean miscella. The oil and gum phases are treated with caustic soda and centrifuged to produce semirefined oil containing about 4% volatiles. The miscella phase, containing about 3.3% lipid-like material and 1% petroleum ether insolubles, is reheated and recycled to the extractor. After the marc is pressed foots are added, and it is desolventized to produce a meal having a residual oil content less than 1%. Although not yet otpimized, the process shows potential for scaleup to pilot plant processing and adaptability to current oil mill solvent operations. Presented at the AOCS annual meeting, Chicago, May 1983.     

Solvent extraction of oil from soybean flour II— pilot plant and two-solvent extractions

The process of grinding soybeans to a fine flour and extracting the flour with hexane was studied on a pilot plant scale. The crude oil from the pilot plant study had 15 ppm phosphorus and was suitable for physical refining after a light acid pretreatment and bleaching. The refined oil showed a Lovibond color of 1.4 yellow and 0.3 red. The pilot plant study also showed that grinding of the soybeans and the separation of solid from miscella were the most difficult steps in solvent extraction with fine flour. A laboratory study on separation of miscella from meal by aqueous ethanol reduced the hold-up volume, but it did not remove all the miscella. A test with betacarotene showed that only the miscella outside the flour particles was displaced. Aqueous ethanol solutions used as a second solvent extracted additional nontriglyceride materials (primarily phospholipids) from the meal. Also, the free fatty acid content of the oil was increased with aqueous ethanol solution wash. The quality of the extracted crude oil was lowered by using a second solvent, but it had the advantage of needing only one centrifugation to separate miscella from meal.     

Phase equilibrium data pertaining to the extraction of cottonseed oil with ethanol and 2-propanol

Summary Basic phase relation data have been obtained relative to the extraction of cottonseed oil with ethanol and 2-propanol, especially as affected by water in the solvent. Mutual solubility diagrams have been constructed for cottonseed oil with ethanol and 2-propanol of various aqueous concentrations. Tie-line data at 30° C. have been obtained for the ternary ethanol-cotton-seed oil-water and 2-propanol-cottonseed oil-water systems. These combined data will be of assistance in the selection of the most desirable temperatures and moisture concentrations in the solvent extraction of cottonseed with these alcohols. Comparison with results previously published for soybean oil suggests that the mutual solubility data for cottonseed oil and aqueous ethanols are applicable to other vegetable oils over a wide range of iodine values. In general, the results indicate that 2-propanol is the more desirable solvent since complete miscibility with the oil can be attained at temperatures below its normal boiling point even at moisture contents as high as 10% by weight whereas ethanol can tolerate only about 1.5% of water. High moisture contents result in more effective separation of the oil from the solvent when the miscella is cooled after extraction. Constant boiling aqueous ethanol and 2-propanol present the disadvantage of requiring greater than atmospheric pressure during extraction in order to attain complete miscibility with the oil. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Ethanol extraction of oil,gossypol and aflatoxin from cottonseed

Commercial processing of cottonseed requires hexane to extract and recover edible oil. Gossypol and aflatoxin are not removed from extracted meals. A bench-top extraction process with 95% (vol/vol) aqueous ethanol (EtOH) solvent has been developed that extracts all three of the above materials with a much less volatile solvent. In this process, cottonseed is pretreated and extracted with ambient 95% EtOH to remove gossypol and then extracted with hot 95% EtOH to extract oil and aflatoxin. Membranes and adsorption columns are used to purify the various extract streams, so that they can be recycled directly. A representative extracted meal contained a total gossypol content of 0.47% (a 70% reduction) and 3 ppb aflatoxin (a 95% reduction). Residual oil content was approximately 2%. Although the process is technically feasible, it is presently not economical unless a mill has a continual, serious aflatoxin contamination problem. However, if a plant cannot meet the hexane emission standards under the Clean Air Act of 1990, this process could provide a safer solvent that may expand the use and increase the value of cottonseed meal as a feed for nonruminants. Presented in part at the AOCS annual meeting, Toronto, Canada, May 1992.     

The extraction of wheat germs,milkweed seeds,and cottonseed by trichloroethylene

Summary Specific gravity-concentration data have been determined for wheat germ oil, milkweed seed oil, and cottonseed oil miscellas where trichloroethylene is used as a solvent. Extraction rate data at two temperatures and pilot plant runs on wheat germs, cottonseed, cottonseed meats, and milkweed seeds indicate increasing extraction time in the order given.     

液液萃取技术在低浓度乙醇水溶液样品检测前处理中的应用

采用液液萃取技术浓缩水中的低浓度乙醇后,用气相色谱法进行测定。首先优化以甲基叔丁基醚(MTBE)为萃取剂的萃取条件:初始乙醇溶液的质量分数win=1.032%、水相与有机相的体积比5∶1,萃取温度291.2 K,搅拌速度为200 r/min.在此基础上,分别加入固体无机盐和离子液体强化液液萃取过程,结果表明固体无机盐K2CO3的盐效应最为明显;随着盐浓度的增加,萃取后有机相中乙醇的质量分数wo也随之增大,从而实现对乙醇水溶液的显著浓缩作用。盐效应的分离机理进一步通过红外光谱分析和量子化学计算,从分子结构和分子间相互作用力方面进行解释,因而实验、理论分析和计算结果保持一致。该样品检测前处理方法具有重现性好、准确度高、快速、简便的特点,且无工业放大效应,为分析水中低浓度有机物提供参考价值。本文中将化工分离过程强化技术应用于样品检测前处理中,体现了化学工程与分析化学的跨学科结合。     

Modeling the solvent extraction of oilseeds

A computer model and an experimental procedure for generating data needed in the model have been developed for the oilseed extraction process. The experiments are relatively simple and are performed with a bench-top extractor. Experimental results and modeling calculations are presented for the extraction of cottonseed using hexane, isopropanol and ethanol. The calculations show that in an alcohol extraction using a chill separation, isopropanol’s greater oil miscibility allows for a lower solvent-to-feed ratio than does ethanol. Using the latter solvent, however, achieves lower residual lipids in the extracted meal because recycled ethanol contains less oil than recycled isopropanol. Presented in part at the AOCS meeting in Honolulu, HI, in 1986.     

Supercritical carbon dioxide extraction of cottonseed with co-solvents

Extraction of cottonseed lipids with supercritical carbon dioxide (SC-CO₂) was conducted with and without a cosolvent, ethanol or 2-propanol (IPA). At 7000 psi and 80°C, the reduced pressure, temperature and density of SC-CO₂ was at 6.5, 1.17 and 1.85, respectively; the specific gravity was 0.87. Under these conditions, CO₂ is denser than most liquid extraction agents such as hexane, ethanol and IPA. The extraction of cottonseed with SC-CO₂ gave a yield of more than 30% (moisture-free basis). This is comparable to yields obtained by the more commonly used solvent, hexane. The crude cottonseed oil extracted by SC-CO₂ was visually lighter than refined cottonseed oil. This was substantiated by colorimetric measurements. No gossypol was detected in the crude oil. However, crude oil extracted by SC-CO₂, to which less than 5% of ethanol or IPA as co-solvent was added, containedca. 200 ppm of gossypol, resulting in the typical dark color of cottonseed crude oil with gossypol. CO₂ extracted a small amount of cottonseed phosphatides, about one-third of that extracted by pure ethanol, IPA or hexane. A second extraction with 100% ethanol or IPA after the initial SC-CO₂ extraction produced a water-soluble lipid fraction that contained a significant amount of gossypol, ranging between 1500 and 5000 ppm. Because pure gossypol is practically insoluble in water, this fraction is believed to be made up of gossypol complexed with polysaccharides and phosphatides. Partially presented at the AOCS 1993 Annual Meeting & Expo in Anaheim, California.     

Solvent extraction of aflatoxins from contaminated agricultural products

Solvent extraction of agricultural products has been suggested as an effective means of removing aflatoxins from mold-damaged commodities. The use of various polar solvents such as the azeotrope of acetone-hexane-water and of 2-propanol-water, aqueous acetone, and aqueous ethanol has been reported in the literature. This paper examines the overall aspects of solvent extraction, in particular the use of the azeotrope of 2-propanol-water, to remove aflatoxins from prepress solvent extracted cottonseed meal.     

Solvent extraction of meat offal

Summary Data are presented to show the effect of the various operating variables on the extraction of meat and bone scrap both in the laboratory and in a pilot plant model of the Iowa State College extractor. From the data presented it has been concluded that the extraction takes place mainly by a washing process with slight diffusion. A possible correlation is suggested for comparing laboratory and pilot plant data. formerly graduate assistant, Iowa Engineering Experiment Station, Iowa State College, Ames, Iowa     

Solvent extraction of cottonseed and peanut oils. VIII. Effects of moisture on the preparation and flaking of cottonseed

Conclusions The results indicate that 9 to 10% moisture in the meats is the best level for the preparation of cottonseed into flakes for solvent extraction. At lower moisture the flakes contain more fines before and after agitation in solvent, and the percolation rate of solvent through a flake bed is lower because of reduced particle size. At higher moisture the amount of oil in the hulls from the beater is greater. Also the flakes produce more fines, and the percolation rate becomes slower because of the softness and pliability of the flaked meat. It is likely that in commercial continuous operations this packing or balling up tendency of the flaked meats may lead to periodic channeling or plugging in the extractor, dryer, conveyors, and filters. These conclusions have been applied in the continuous pilot plant solvent extraction of three lots of prime cottonseed. The results substantiate the findings herein and will be reported in a separate publication. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Water accumulation in the alcohol extraction of cottonseed

The critical moisture content of cottonseed flakes extracted with an aqueous alcohol solvent can be defined as that flake moisture level at which the flakes lose no moisture during extraction. This study shows that the critical moisture content for aqueous ethanol (92%, w/w) is 3%. For aqueous isopropanol (88%, w/w) this value is 6%. If the moisture contents of the flakes are above these levels, then the solvents pick up moisture. For moisture contents below this level, the flakes adsorb moisture and actually dry the alcohol. It is proposed that this latter capability can be used as a basis for a method to control water accumulation in aqueous alcohol solvent extractions.     

Ultrasonic extraction of ferulic acid from Angelica sinensis

In this paper, the extraction of ferulic acid, a pharmacologically active ingredient from the root of Angelica sinensis with ultrasonic extraction was investigated. Percolation and supercritical fluid extraction (SFE) were also employed to make comparisons with ultrasonic extraction. Three variables, which including the concentration of solvent, the ratio of solvent volume to sample (mL/g), and extraction time, were found to have great influence on ultrasonic extraction. The optimum extraction conditions were using pure ethanol with a ratio of solvent volume to sample 8:1 (mL/g) and extraction time of 30 min. Under the optimum extraction conditions, the extraction yield could reach 6.5% mass fraction, which was higher than that of SFE process with ethanol as co‐solvent and nearly a content of ferulic acid 1.0%; both the yield and the content of ferulic acid were higher than those obtained by percolation. Moreover, the time of ultrasonic extraction was significantly shortened. Overall, Ultrasonic extraction was shown to be highly efficient in the extraction of ferulic acid from Angelica sinensis.     

Ultrasonic extraction of ferulic acid from Ligusticum chuanxiong

The extraction of ferulic acid, a pharmacologically active ingredient from the root of Ligusticum chuanxiong, with ultrasonic extraction was investigated. Percolation and supercritical fluid extraction (SFE) were employed to make comparisons with ultrasonic extraction. Three variables, which included the concentration of solvent, the ratio of solvent volume/sample (mL/g), and extraction time, were found to have a great influence on ultrasonic extraction. The optimum extraction was with pure ethanol with a solvent volume/sample ratio 8:1 (mL/g) and extraction time of 30 min. Under the optimum extraction conditions, the extraction yield could reach 8.8% which was higher than that using SFE with ethanol as co-solvent and a content of ferulic acid of 0.7%; both the yield and the content were higher than those obtained by percolation. Ultrasonic extraction significantly shortened the time required for the extraction process. Overall, ultrasonic extraction was shown to be highly efficient in the extraction of ferulic acid from Ligusticum chuanxiong.     

双液相萃取棉籽油制备脂肪酸甲酯

以双液相萃取技术处理棉籽,在得到脱毒棉粕的同时得到含有高质量毛油的非极性相。以非极性相作为与甲醇进行酯交换反应的原料,得到脂肪酸甲酯和甘油。考察了非极性相溶剂石油醚与棉籽油的比例对酯交换转化率和洗涤粗产品用水量的影响,确定了石油醚与棉籽油的最佳质量比为3,在此条件下,洗涤用水量可降低一半。考察了醇油比、催化剂用量、反应温度、反应时间等参数对转化率的影响。应用正交实验的方法找出酯交换反应的适宜条件为：醇油比6：1,催化剂用量1.1％,反应温度60℃,反应时间120min。在此反应条件下,产物中脂肪酸甲酯的含量可达97.4％。     

Production of ethanol by continuous fermentation and liquid–liquid extraction

A continuous pilot plant was constructed for fermentation production of ethanol, using liquid–liquid extraction to remove the product and with recycle of the fermented broth raffinate. The plant was operated for up to 18 days with feed glucose concentrations in the range 10·0–45·8% (w/w). The solvent was n-dodecanol and immobilised yeast was used to overcome the problem of emulsification. The concentration of by-products in the fermented broth had no adverse effect on the rate of ethanol production. A mathematical model to predict the time required for achievement of 99% of the steady-state by-products concentrations was shown to be in good agreement with the experimentally determined concentration of the main by-product, glycerol. At a feed glucose concentration of 45·8% (w/w), the aqueous purge was equivalent to 2·8 m³ of effluent per m³ of ethanol produced and represented a 78% reduction in the volume of the aqueous purge compared with using a feed containing 10% (w/w) glucose.     

淫羊藿超声提取工艺优化

目的:优选淫羊藿的超声提取工艺。方法:以淫羊藿苷的提取率为指标,高效液相色谱检测含量,应用正交试验优化淫羊藿的最佳超声提取工艺条件。结果:影响提取的主次因素为ABDC(A:乙醇浓度;B:物料比;C:提取温度;D:提取时间)。最佳提取条件为:超声功率为300W、60%乙醇溶液、液固比25:1、提取时间60min、提取温度50℃。根据优选工艺验证实验表明,有效成分提取率94.88%,重现性较好。结论:优选得到的工艺稳定可行。     

Subcritical co‐solvents extraction of lipid from wet microalgae pastes of Nannochloropsis sp.

In this paper subcritical co‐solvents extraction (SCE) of algal lipid from wet pastes of Nannochloropsis sp. is examined. The influences of five operating parameters including the ratio between ethanol to hexane, the ratio of mixed solvents to algal biomass (dry weight), extraction temperature, pressure, and time were investigated. The determined optimum extraction conditions were 3:1 (hexane to ethanol ratio), 10:1 ratio (co‐solvents to microalgae (dry weight) ratio), 90°C, 1.4 MPa, and 50 min, which could produce 88% recovery rate of the total lipids. In addition, electron micrographs of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were conducted to show that the algal cell presented shrunken, collapsed with some wrinkles and microholes after SCE extraction. The main composition of total lipids extracted under the optimum conditions was TAG which represented more than 80%. And the fatty acid profile of triglycerides revealed that C16:0 (35.67 ± 0.2%), C18:1 (26.84 ± 0.044%) and C16:1 (25.96 ± 0.011%) were dominant. Practical applications: The reported method could save energy consumption significantly through avoiding deep dewatering (for example drying). The composition of the extracted lipid is suitable for the production of high quality biodiesel.