Extraction auxiliary equipment

Auxiliary equipment and fittings that require seals, gaskets, diaphragms, filter media, and membranes should exclude materials that permit the possibility of extractable, shedding, and microbial activity. 

AUXILIARY EQUIPMENT. The dispersed phase in an extraction tower is allowed to coalesce at some point into a continuous layer from which one product stream is withdrawn. The interface between this layer and the predominant continuous phase is set in an open section at the top or bottom of a packed tower in a sieve-plate tower it is set in an open section near the top of the tower when the light phase is dispersed. If the heavy phase is dispersed, the interface is kept near the bottom of the tower. The interface level may be automatically controlled by a vented overflow leg for the heavy phase, as in a continuous gravity decanter. In large columns the interface is often held at the desired point by a level controller actuating a valve in the heavy-liquid discharge line. 

Evaporation, distillation, and extraction processes are carried out in several stages. Even reactions are carried out in several vessels. Since each stage requires its own auxiliary equipment, telescoping the stages could be highly beneficial. Performing all the reactions in one pot followed by isolation is the most ideal situation. Fermentation is an example of this philosophy, where complex products are formed from simple chemicals. 

Fig.16 Auxiliary equipment for changing worn parts (O. K. Mammut crusher), a hammer lifting device, b hammer spindle extracting device, c discharge grid extracting device...

Automatic Samplers—An automatic sampler includes not only the automatic sampling device that extracts the samples from the line, but also a suitable probe, connecting lines, auxiliary equipment, and a container in which the sample is collected. It must maintain sample integrity. Refer to API MPMS Chapter 8.2. Automatic samplers are classified as follows ... 

Residence time can be as short as 10 sec. One 750 gpm unit is said to have a total liquid holdup of 200 gal. From 3-10 stages per unit have been reported, although Table 14.8 shows a range of 1.8-7.7. A 65 in. dia casing can accommodate throughputs up to 25,000 gal/hr. An economic comparison of a Podbielniak with other extractors is made in Table 14.5(b). Although its basic cost is high, it requires few auxiliaries so that the overall cost of an extraction plant is not drastically out of line in every instance. Nevertheless, this equipment is used primarily when short residence time and other characteristic features are indispensable. 

Methylene chloride is used in many paint and varnish stripping formulations, as a solvent for cold cleaning of metal parts, as an extraction solvent for heat sensitive substances, as an extraction media for pharmaceutical products, as a solvent to clean polyurethane molding equipment, as an auxiliary blowing agent for flexible polyurethane foam, and as a solvent in the manufacture of... 

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