Continuous extraction, of liquids

Sometimes an air bubble enters the tube E and prevents the regular flow of liquid from B -, the air bubble is easily removed by shaking the rubber tube. The flask A is heated (e.g., by a ring burner) so that distillation proceeds at a rapid rate the process is a continuous one. If the liquid to be steam distilled is lighter than water, the receiver must be modified so that the aqueous liquors are drawn off from the bottom (see Continuous Extraction of Liquids, Section 11,44). 

Conglomerate, 25 Congruent melting point, 29 Congo red, 979 Conjugate solutions, 17-20 Consolute temperature, 17, 18, 19, 20 Continuous extraction, of liquids by solvents, 152-154... 

Continuous extractions of liquids. When the organic compounds is more soluble in water than in the organic solvent (i.e. the distribution coefficient between the organic solvent and water is small), very large quantities of organic solvent must be employed to obtain even a moderately efficient extraction. This may be avoided by the use of an apparatus for continuous extraction where only relatively small volumes of solvent are required. 

POROCRITICAL FLUID EXTRACTION A NEW TECHNIQUE FOR CONTINUOUS EXTRACTION OF LIQUIDS WITH NEAR-CRITICAL FLUIDS. Marc Sims, James R. Robinson and Anthony J. Dennis, (Marc Sims SFE, Setec Inc., Tastemaker), 1012 Grayson... 

A new supercritical fluid process has been developed for the continuous extraction of liquids. The most useful solvent employed in the recently patented process is supercritical or near-critical carbon dioxide(l). At the heart of the process are porous membranes. Their porosity combined with a near-critical fluid s high diffusivity create a dynamic non-dispersive contact between solvent and feed liquid. The technique is dubbed porocritical fluid extraction and will be commercialized as the Porocrit Process. 

The turn-key multipurpose high pressure pilot unit shown in picture 1 can be used for the continuous extraction of liquid products in a column with structured packings and for the batch extraction of solids in a extraction vessel. It is assembled using the following proven basic modules (see also figure 1) ... 

As reported in a lot of reviews, extractions with supercritical solvents have a very promising commercial potential. Until now the commercialization is mainly restricted to batchwise extraction of solids with carbon dioxide (e g. decaffeination of coffee and tea, extraction of hop). Laboratory experiments and operation of small-scale pilot plants gave favourable economic values for continuous extraction of liquids with C02 and other gases. Only a few extractions with C02 or C HS are performed already on a small industrial scale. For research purposes and product development a new high pressure counter-current extraction plant was erected. To get greater amounts of product the explosionproof plant was constructed in pilot scale using a special modular concept and an effective visual control system. 

The design of a multi-purpose plant for the continuous extraction of liquids with supercritical fluids is presented. To provide flexibility in order to treat different feedstocks, a modular concept was developed based on experience gained in the operation of bench-scale and pilot plants. Four test systems were chosen in order to determine the proper dimensions for the equipment. Based on experimental data, e.g. measurements of flooding points and maximum flows for various column internals, the design pressure and temperature and heat exchange requirements were determined. The plant was built by a German manufacturer and was operated successfully by a Canadian company in Edmonton, Alberta. 

Continuous Liquid-Liquid Extraction. Continuous extraction of liquid-liquid systems is also possible and particularly valuable when the component to be separated is only slightly soluble in the extraction solvent. The advantage of using continuous extraction is that it can be carried out with a limited amount of solvent. In batchwise extractions a prohibitive number of individual extractions might have to be performed to accomplish the same overall extraction. Specialized apparatus, however, is required for continuous liquid-liquid extraction. 

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